7 CFR 319.55-3 - Ports of entry.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Rice Rules and Regulations § 319.55-3 Ports of entry. (a) For importations of seed or paddy rice from the Republic of Mexico, permits will be issued for entry... Quarantine Programs. (b) For importations of rice straw and rice hulls from all foreign countries, permits...

7 CFR 319.55-2 - Application for permit.

Code of Federal Regulations, 2010 CFR

2010-01-01

... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Rice Rules and Regulations § 319.55-2 Application for permit. (a) Application for a permit to import seed or paddy rice from Mexico or rice straw or rice hulls from any country, may be made to the Plant Protection and Quarantine Programs, indicating in...

7 CFR 319.55-2 - Application for permit.

Code of Federal Regulations, 2011 CFR

2011-01-01

... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Rice Rules and Regulations § 319.55-2 Application for permit. (a) Application for a permit to import seed or paddy rice from Mexico or rice straw or rice hulls from any country, may be made to the Plant Protection and Quarantine Programs, indicating in...

7 CFR 319.55-3 - Ports of entry.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Rice Rules and Regulations § 319.55-3 Ports of entry. (a) For importations of seed or paddy rice from the Republic of Mexico, permits will be issued for entry... Quarantine Programs. (b) For importations of rice straw and rice hulls from all foreign countries, permits...

In vivo thermoterapy: attempt to eliminate virus in potato tuber

NASA Astrophysics Data System (ADS)

Ayu Astarini, Ida; Margareth, Deborah; Temaja, I. Gede Rai Maya

2018-03-01

Potato is one of an important vegetable crop in Indonesia, including Bali. Main potato production areas in Bali are at Bedugul region, 1.200 m above sea level. Potato production in Bali continued to decrease due to diseases infection, such as early blight, late blight, black leg and virus diseases. Potato farmers in Bali usually set aside their harvest as seed potatoes, resulting in virus diseases being carried out on the next planting seasons and eventually would decrease potato production both in quantity and quality. Four types of virus were confirmed: PVY, PVX, PVS and PRLV. A number of studies have reported thermotherapy technique has been employed to eliminate potato virus in vitro. However, this technique is not readily available for farmers, since there is no established tissue culture laboratory to support. Therefore, there is an urgent need to develop a more practical method. The objective of this study was to eliminate virus on seed potatoes using thermotherapy on tuber. Seed potatoes with 1 cm sprout which were virus positive were placed on sterile charred rice paddy husk, and then put into a humidified incubator. Tubers were exposed to 37°C for four days followed by 34°C for three days alternately for two weeks and three weeks duration. Four tubers received heat exposure regime for each virus type. After thermotherapy, potato tubers were transferred to pots containing charred rice paddy husk and maintain for three weeks until new leaves emerge for virus analyses. Results show that seed tubers experienced delayed growth after thermotherapy. Control plants sprout one week after thermotherapy, while treated plants were not yet sprouting. Experiment is currently underway. It is expected that heat treatment on tuber will give a practical method for farmers to eliminate virus of seed potatoes.

Antifungal evaluation studies of copper sulfide nano-aquaformulations and its impact on seed quality of rice ( Oryzae sativa)

NASA Astrophysics Data System (ADS)

Sidhu, Anjali; Barmota, Heena; Bala, Anju

2017-11-01

Surface capped copper sulfide nano-aquaformulations were prepared by in situ combination of copper ions with sulfide ions using sonochemical method, followed by microwave irradiations, in the presence of capping agents. Prepared nano-aquaformulations were characterized for particle size, morphology and optical properties. The in vitro antifungal evaluations studies indicated multifold efficacy against Alternaria alternata, Drechslera oryzae and Curvularia lunata in comparison to standard used. The in vivo seed treatment on discoloured paddy seeds showed the optimum results on application @ 7μg/ml for 2 h in case of citrate capped copper sulfide nanoformulation (NCuS3). Significant reduction in seed rot and seedling blight was observed with favourable effect on germination and growth parameters at this concentration.

Paddys Run Streambank Stabilization Project at the Fernald Preserve, Harrison, OH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hooten, Gwendolyn; Hertel, Bill; Homer, John

The Fernald Preserve is a former uranium-processing plant that underwent extensive remediation pursuant to CERCLA and is now managed by the US DOE Office of Legacy Management. While remediation of buildings and soil contamination was completed in 2006, aquifer remediation is ongoing. Paddys Run is a second-order stream that runs to the south along the western side of the Fernald Preserve. The Paddys Run watershed encompasses nearly 41 km2 (16 mi2), including most of the Fernald site. Field personnel conducting routine site inspections in March 2014 observed that Paddys Run was migrating east via bank erosion into the “Pit 3more » Swale,” an area of known surface-water contamination. The soil there was certified pursuant to site regulatory agreements and meets all final remediation levels. However, weekly surface-water monitoring is conducted from two puddles within the swale area, when water that exceeds the final remediation levels is present. Paddys Run had migrated east approximately 4 m (13 ft) in 2 years and was approximately 29 m (95 ft) from the sample location. This rapid migration threatened existing conditions that allowed for continued monitoring of the swale area and also threatened Paddys Run water quality. Therefore, DOE and regulators determined that the east bank of Paddys Run required stabilization. This was accomplished with a design that included the following components: relocation of approximately 145 m (475 ft) of streambed 9 m (30 ft) west, installation of a rock toe along the east bank, installation of two cross-vane in-stream grade-control structures, stabilization of a portion of the east bank using soil encapsulated lifts, and regrading, seeding, and planting within remaining disturbed areas. In an effort to take advantage of low-flow conditions in Paddys Run, construction was initiated in September 2014. Weather delays and subsurface flow within the Paddys Run streambed resulted in an interim shutdown of the project area in December 2014. Construction activities resumed in April 2015, with completion in November 2015. To date, this stabilization project has been successful. The regraded bank and streambed have remained stable, and no compromise to installed cross-vanes, the rock toe, or the soil encapsulated lifts has been observed.« less

Simulating water and nitrogen loss from an irrigated paddy field under continuously flooded condition with Hydrus-1D model.

PubMed

Yang, Rui; Tong, Juxiu; Hu, Bill X; Li, Jiayun; Wei, Wenshuo

2017-06-01

Agricultural non-point source pollution is a major factor in surface water and groundwater pollution, especially for nitrogen (N) pollution. In this paper, an experiment was conducted in a direct-seeded paddy field under traditional continuously flooded irrigation (CFI). The water movement and N transport and transformation were simulated via the Hydrus-1D model, and the model was calibrated using field measurements. The model had a total water balance error of 0.236 cm and a relative error (error/input total water) of 0.23%. For the solute transport model, the N balance error and relative error (error/input total N) were 0.36 kg ha -1 and 0.40%, respectively. The study results indicate that the plow pan plays a crucial role in vertical water movement in paddy fields. Water flow was mainly lost through surface runoff and underground drainage, with proportions to total input water of 32.33 and 42.58%, respectively. The water productivity in the study was 0.36 kg m -3 . The simulated N concentration results revealed that ammonia was the main form in rice uptake (95% of total N uptake), and its concentration was much larger than for nitrate under CFI. Denitrification and volatilization were the main losses, with proportions to total consumption of 23.18 and 14.49%, respectively. Leaching (10.28%) and surface runoff loss (2.05%) were the main losses of N pushed out of the system by water. Hydrus-1D simulation was an effective method to predict water flow and N concentrations in the three different forms. The study provides results that could be used to guide water and fertilization management and field results for numerical studies of water flow and N transport and transformation in the future.

Compost maturity and nitrogen availability by co-composting of paddy husk and chicken manure amended with clinoptilolite zeolite.

PubMed

Latifah, Omar; Ahmed, Osumanu Haruna; Susilawati, Kassim; Majid, Nik Muhamad

2015-04-01

The availability of paddy husk from rice processing plants remains high owing to increase in the worldwide rice consumption. Increasing demand for chicken products leads to poultry wastes production. Co-composting of the aforementioned wastes could solve the indiscriminate disposal of these wastes. Thus, co-composting of paddy husk and chicken slurry with clinoptilolite zeolite and urea as additive was carried out. Clinoptilolite zeolite was used to enhance ammonium and nitrate retention in the compost. Temperature of the compost was monitored three times daily for 55 days. Cation exchange capacity, organic matter, ash, humic acids, pH, total C, N, C/N ratio; total P, exchangeable Ca, Mg, K, NH4+, NO3-, and heavy metals contents were determined using standard procedures. pH, total N, humic acids, ash, NH4+, NO3-, P, Ca, Mg, and K contents increased but the salinity, heavy metals contents, and microbial population were low after the co-composting process. Zea mays L. (test crop) seed germination rate in distilled water and the compost were not significantly different. Growth of Spinach oleracea (test crop) on a peat-based growing medium and the compost was also not significantly different. These findings were possible because the clinoptilolite zeolite used in co-composting reduced accumulation of heavy metals that may have damage effects on the test crops. Mature compost with good agronomic properties can be produced by co-composting chicken slurry and paddy husk using clinoptilolite zeolite and urea as additives. © The Author(s) 2015.

Expression of barley SUSIBA2 transcription factor yields high-starch low-methane rice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, J.; Hu, C.; Yan, X.

Atmospheric methane is the second most important greenhouse gas after carbon dioxide, and is responsible for about 20% of the global warming effect since pre-industrial times. Rice paddies are the largest anthropogenic methane source and produce 7–17% of atmospheric methane. Warm waterlogged soil and exuded nutrients from rice roots provide ideal conditions for methanogenesis in paddies with annual methane emissions of 25–100-million tonnes. This scenario will be exacerbated by an expansion in rice cultivation needed to meet the escalating demand for food in the coming decades4. There is an urgent need to establish sustainable technologies for increasing rice production whilemore » reducing methane fluxes from rice paddies. However, ongoing efforts for methane mitigation in rice paddies are mainly based on farming practices and measures that are difficult to implement5. Despite proposed strategies to increase rice productivity and reduce methane emissions4,6, no high-starch low-methane-emission rice has been developed. Here we show that the addition of a single transcription factor gene, barley SUSIBA2, conferred a shift of carbon flux to SUSIBA2 rice, favouring the allocation of photosynthates to aboveground biomass over allocation to roots. The altered allocation resulted in an increased biomass and starch content in the seeds and stems, and suppressed methanogenesis, possibly through a reduction in root exudates. Three-year field trials in China demonstrated that the cultivation of SUSIBA2 rice was associated with a significant reduction in methane emissions and a decrease in rhizospheric methanogen levels. SUSIBA2 rice offers a sustainable means of providing increased starch content for food production while reducing greenhouse gas emissions from rice cultivation. Approaches to increase rice productivity and reduce methane emissions as seen in SUSIBA2 rice may be particularly beneficial in a future climate with rising temperatures resulting in increased methane emissions from paddies.« less

Expression of barley SUSIBA2 transcription factor yields high-starch low-methane rice

NASA Astrophysics Data System (ADS)

Su, J.; Hu, C.; Yan, X.; Jin, Y.; Chen, Z.; Guan, Q.; Wang, Y.; Zhong, D.; Jansson, C.; Wang, F.; Schnürer, A.; Sun, C.

2015-07-01

Atmospheric methane is the second most important greenhouse gas after carbon dioxide, and is responsible for about 20% of the global warming effect since pre-industrial times. Rice paddies are the largest anthropogenic methane source and produce 7-17% of atmospheric methane. Warm waterlogged soil and exuded nutrients from rice roots provide ideal conditions for methanogenesis in paddies with annual methane emissions of 25-100-million tonnes. This scenario will be exacerbated by an expansion in rice cultivation needed to meet the escalating demand for food in the coming decades. There is an urgent need to establish sustainable technologies for increasing rice production while reducing methane fluxes from rice paddies. However, ongoing efforts for methane mitigation in rice paddies are mainly based on farming practices and measures that are difficult to implement. Despite proposed strategies to increase rice productivity and reduce methane emissions, no high-starch low-methane-emission rice has been developed. Here we show that the addition of a single transcription factor gene, barley SUSIBA2 (refs 7, 8), conferred a shift of carbon flux to SUSIBA2 rice, favouring the allocation of photosynthates to aboveground biomass over allocation to roots. The altered allocation resulted in an increased biomass and starch content in the seeds and stems, and suppressed methanogenesis, possibly through a reduction in root exudates. Three-year field trials in China demonstrated that the cultivation of SUSIBA2 rice was associated with a significant reduction in methane emissions and a decrease in rhizospheric methanogen levels. SUSIBA2 rice offers a sustainable means of providing increased starch content for food production while reducing greenhouse gas emissions from rice cultivation. Approaches to increase rice productivity and reduce methane emissions as seen in SUSIBA2 rice may be particularly beneficial in a future climate with rising temperatures resulting in increased methane emissions from paddies.

[Distribution characteristics of copper in soil and rape around Tongling mining area].

PubMed

Shen, Chang-Gao; Gao, Chao; Wang, Deng-Feng; Wang, Lei; Chen, Fu-Rong

2007-10-01

Soil and rape samples around Tongling mining area were collected, and their copper (Cu) contents were investigated. The results showed that the upland soil developed on the slope deposit around the mining area as well as the paddy soil distributed in lower reaches was heavily polluted by Cu, while the fluvo-aquic soil further from the mining area was less contaminated. Though the Cu content in paddy soil and upland soil was nearly the same, its bioavailability was higher in paddy soil, due to the Cu pollution of irrigated water. There was a significant correlation between available and total Cu in these three types of soil. The activation rate of soil Cu (percentage of available Cu in total Cu) was 15.0% on average, which was positively correlated with soil total Cu and organic matter while negatively correlated with soil pH and Mn. The average Cu content in rape seed and stalk was 4.0 and 5.8 mg x kg(-1), respectively. The rape Cu content increased obviously with increasing soil available Cu content when the soil available Cu content was relatively low, but the Cu absorption and accumulation by rape decreased gradually when the soil available copper content was higher than 30 mg x kg(-1).

Assessing energy efficiencies and greenhouse gas emissions under bioethanol-oriented paddy rice production in northern Japan.

PubMed

Koga, Nobuhisa; Tajima, Ryosuke

2011-03-01

To establish energetically and environmentally viable paddy rice-based bioethanol production systems in northern Japan, it is important to implement appropriately selected agronomic practice options during the rice cultivation step. In this context, effects of rice variety (conventional vs. high-yielding) and rice straw management (return to vs. removal from the paddy field) on energy inputs from fuels and consumption of materials, greenhouse gas emissions (fuel and material consumption-derived CO(2) emissions as well as paddy soil CH(4) and N(2)O emissions) and ethanol yields were assessed. The estimated ethanol yield from the high-yielding rice variety, "Kita-aoba" was 2.94 kL ha(-1), a 32% increase from the conventional rice variety, "Kirara 397". Under conventional rice production in northern Japan (conventional rice variety and straw returned to the paddy), raising seedlings, mechanical field operations, transportation of harvested unhulled brown rice and consumption of materials (seeds, fertilizers, biocides and agricultural machinery) amounted to 28.5 GJ ha(-1) in energy inputs. The total energy input was increased by 14% by using the high-yielding variety and straw removal, owing to increased requirements for fuels in harvesting and transporting harvested rice as well as in collecting, loading and transporting rice straw. In terms of energy efficiency, the variation among rice variety and straw management scenarios regarding rice varieties and rice straw management was small (28.5-32.6 GJ ha(-1) or 10.1-14.0 MJ L(-1)). Meanwhile, CO(2)-equivalent greenhouse gas emissions varied considerably from scenario to scenario, as straw management had significant impacts on CH(4) emissions from paddy soils. When rice straw was incorporated into the soil, total CO(2)-equivalent greenhouse gas emissions for "Kirara 397" and "Kita-aoba" were 25.5 and 28.2 Mg CO(2) ha(-1), respectively; however, these emissions were reduced notably for the two varieties when rice straw was removed from the paddy fields in an effort to mitigate CH(4) emissions. Thus, rice straw removal avers itself a key practice with respect to lessening the impacts of greenhouse gas emissions in paddy rice-based ethanol production systems in northern Japan. More crucially, the rice straw removed is available for ethanol production and generation of heat energy with a biomass boiler, all elements required for biomass-to-ethanol transformation steps including saccharification, fermentation and distillation. This indicates opportunities for further improvement in energy efficiency and reductions in greenhouse gas emissions under whole rice plant-based bioethanol production systems. Copyright © 2010 Elsevier Ltd. All rights reserved.

Relationships among bulk soil physicochemical, biochemical, and microbiological parameters in an organic alfalfa-rice rotation system.

PubMed

Lopes, Ana R; Bello, Diana; Prieto-Fernández, Ángeles; Trasar-Cepeda, Carmen; Manaia, Célia M; Nunes, Olga C

2015-08-01

The microbial communities of bulk soil of rice paddy fields under an ancient organic agriculture regimen, consisting on an alfalfa-rice rotation system, were characterized. The drained soil of two adjacent paddies at different stages of the rotation was compared before rice seeding and after harvesting. The relationships among the soil microbial, physicochemical, and biochemical parameters were investigated using multivariate analyses. In the first year of rice cropping, aerobic cultivable heterotrophic populations correlated with lineages of presumably aerobic bacteria (e.g., Sphingobacteriales, Sphingomonadales). In the second year of rice cropping, the total C content correlated with presumable anaerobic bacteria (e.g., Anaerolineae). Independently of the year of rice cropping, before rice seeding, proteolytic activity correlated positively with the cultivable aerobic heterotrophic and ammonifier populations, the soil catabolic profile and with presumable aerobes (e.g., Sphingobacteriales, Rhizobiales) and anaerobes (e.g., Bacteroidales, Anaerolineae). After harvesting, strongest correlations were observed between cultivable diazotrophic populations and bacterial groups described as comprising N2 fixing members (e.g., Chloroflexi-Ellin6529, Betaproteobacteria, Alphaproteobacteria). It was demonstrated that chemical parameters and microbial functions were correlated with variations on the total bacterial community composition and structure occurring during rice cropping. A better understanding of these correlations and of their implications on soil productivity may be valid contributors for sustainable agriculture practices, based on ancient processes.

Mass loading and partitioning of dioxins in irrigation runoff from Japanese paddy fields: combination usage of the CALUX assay with HRGC/HRMS.

PubMed

Kanematsu, Masakazu; Shimizu, Yoshihisa; Sato, Keisuke; Kim, Suejin; Suzuki, Tasuma; Park, Baeksoo; Saino, Reiko; Nakamura, Masafumi

2009-08-01

Lack of understanding of dioxins mass loading into the aquatic environment motivated the quantitative investigation of dioxins runoff from paddy fields during one entire irrigation period in the Minakuchi region, Japan. Combination use of the chemically activated luciferase gene expression (CALUX) bioassay together with high resolution gas chromatography and high resolution mass spectrometry (HRGC/HRMS) enabled efficient investigation of dioxins contamination. The result shows that the congener profile in irrigation runoff is quite similar to those in paddy soil samples and that 1,3,6,8-/1,3,7,9-TeCDD and OCDD derived from pesticides (i.e., pentachlorophenol (PCP) and chloronitrophen (CNP)) are predominant congeners in irrigation runoff. Although it is not surprising that dioxins concentration was strongly dependent on the suspended solids (SS) and the particulate organic carbon (POC) concentration, the dioxins toxic equivalency (TEQ) concentration was extremely high in irrigation runoff (max: 16,380 pg/L, corresponding to 12 pg WHO-TEQ/L) due to runoff of highly contaminated paddy soils. The results imply that dioxins concentration in a river must be monitored considering soil contamination level, land use, and soil runoff events. Using experimental data and a theoretical model, the mass loading of dioxins from the paddy fields by irrigation runoff was estimated to be 1.50 x 10(-2)% of total amount of dioxins accumulated in the paddy fields. Given the results of other researches, it is implied the following: 1) large portion of paddy soils released into the river appear to be settled on the riverbed due to small water flux, and, then, washed out and transported by rainfall runoff after irrigation period, 2) rainfall runoff itself also wash out paddy soils directly from paddy fields. Combination use of the CALUX bioassay with HRGC/HRMS is demonstrated as an alternative strategy to assess dioxins contamination in the environment.

Impact of Rice Paddy Areas Decrease on Local Climate over Taiwan

NASA Astrophysics Data System (ADS)

Lo, M. H.; Wen, W. H.; Chen, C. C.

2014-12-01

Agricultural irrigation practice is one of the important anthropogenic processes in the land surface modeling. Irrigation can decrease local surface temperature with alternating surface energy partitioning. Rice paddy is the major food crop in Asian monsoon region and rice is grown under flooded conditions during the growing season; hence, the rice paddy can be considered as an open water body, which has more impacts on the surface energy budget than other cropland does. In this study, we explore how the rice paddy area changes affect Taiwan's regional climate from both observational data and numerical modeling exercise. The Weather Research and Forecasting (WRF) model is utilized to explore impacts of rice paddy area changes on the regional climate, and energy and water budget changes. In addition, temperature datasets from six automatic weather stations in the northern Taiwan and two stations in the southern Taiwan are analyzed in this study to explore how the Daily Temperature Range (DTR) changes with the decreased rice paddy areas. Previous studies show that due to the urban heat island effect, aerosol direct and indirect effects, and global warming, the DTR has decreased in the past 4 decades observed from most of the weather stations around Taiwan. However, the declined rice paddy area may increase the DTR with higher Bowen ratio during the daytime. Preliminary results show that DTR is decreased in weather stations near the urban area, but increased in weather stations near fallow areas in the past 20 years. It shows that different land use changes may have opposite impacts on local and regional climate.

Annual methane and nitrous oxide emissions from rice paddies and inland fish aquaculture wetlands in southeast China

NASA Astrophysics Data System (ADS)

Wu, Shuang; Hu, Zhiqiang; Hu, Tao; Chen, Jie; Yu, Kai; Zou, Jianwen; Liu, Shuwei

2018-02-01

Inland aquaculture ponds have been documented as important sources of atmospheric methane (CH4) and nitrous oxide (N2O), while their regional or global source strength remains unclear due to lack of direct flux measurements by covering more typical habitat-specific aquaculture environments. In this study, we compared the CH4 and N2O fluxes from rice paddies and nearby inland fish aquaculture wetlands that were converted from rice paddies in southeast China. Both CH4 and N2O fluxes were positively related to water temperature and sediment dissolved organic carbon, but negatively related to water dissolved oxygen concentration. More robust response of N2O fluxes to water mineral N was observed than to sediment mineral N. Annual CH4 and N2O fluxes from inland fish aquaculture averaged 0.51 mg m-2 h-1 and 54.78 μg m-2 h-1, amounting to 42.31 kg CH4 ha-1 and 2.99 kg N2O-N ha-1, respectively. The conversion of rice paddies to conventional fish aquaculture significantly reduced CH4 and N2O emissions by 23% and 66%, respectively. The emission factor for N2O was estimated to be 0.46% of total N input in the feed or 1.23 g N2O-N kg-1 aquaculture production. The estimate of sustained-flux global warming potential of annual CH4 and N2O emissions and the net economic profit suggested that such conversion of rice paddies to inland fish aquaculture would help to reconcile the dilemma for simultaneously achieving both low climatic impacts and high economic benefits in China. More solid direct field measurements from inland aquaculture are in urgent need to direct the overall budget of national or global CH4 and N2O fluxes.

Rapid in situ assessment for predicting soil quality using an algae-soaked disc seeding assay.

PubMed

Nam, Sun-Hwa; Moon, Jongmin; Kim, Shin Woong; Kim, Hakyeong; Jeong, Seung-Woo; An, Youn-Joo

2017-11-16

The soil quality of remediated land is altered and this land consequently exerts unexpected biological effects on terrestrial organisms. Therefore, field evaluation of such land should be conducted using biological indicators. Algae are a promising new biological indicator since they are a food source for organisms in higher soil trophic levels and easily sampled from the soil. Field evaluation of soil characteristics is preferred to be testing in laboratory conditions because many biological effects cannot be duplicated during laboratory evaluations. Herein, we describe a convenient and rapid algae-soaked disc seeding assay for assessing soil quality in the field based on soil algae. The collection of algae is easy and rapid and the method predicts the short-term quality of contaminated, remediated, and amended farm and paddy soils. The algae-soaked disc seeding assay is yet to be extensively evaluated, and the method cannot be applied to loamy sand soil in in situ evaluations. The algae-soaked disc seeding assay is recommended for prediction of soil quality in in situ evaluations because it reflects all variations in the environment. The algae-soaked disc seeding assay will help to develop management strategies for in situ evaluation.

Genome-Wide Association of Rice Blast Disease Resistance and Yield-Related Components of Rice.

PubMed

Wang, Xueyan; Jia, Melissa H; Ghai, Pooja; Lee, Fleet N; Jia, Yulin

2015-12-01

Robust disease resistance may require an expenditure of energy that may limit crop yield potential. In the present study, a subset of a United States Department of Agriculture rice core collection consisting of 151 accessions was selected using a major blast resistance (R) gene, Pi-ta, marker and was genotyped with 156 simple sequence repeat (SSR) markers. Disease reactions to Magnaporthe oryzae, the causal agent of rice blast disease, were evaluated under greenhouse and field conditions, and heading date, plant height, paddy and brown seed weight in two field environments were analyzed, using an association mapping approach. A total of 21 SSR markers distributed among rice chromosomes 2 to 12 were associated with blast resistance, and 16 SSR markers were associated with seed weight, heading date, and plant height. Most noticeably, shorter plants were significantly correlated with resistance to blast, rice genomes with Pi-ta were associated with lighter seed weights, and the susceptible alleles of RM171 and RM6544 were associated with heavier seed weight. These findings unraveled a complex relationship between disease resistance and yield-related components.

Sustainability of terraced paddy fields in traditional satoyama landscapes of Japan.

PubMed

Fukamachi, Katsue

2017-11-01

Terraced paddy fields are essential components of the traditional cultural landscape of Japan, the satoyama landscape. They have been sustainably cultivated in a variety of ecological and social environments through time, and are highly valued as local resources with multiple functions. This paper reviews the recent nationwide movement for conservation of satoyama landscapes and shows that over the last decades, the government has increasingly created policies based on national regulation or international frameworks that concern the culture and environment in rural areas. Recent measures for the sustainability of terraced paddy fields do not only focus on rice terraces, but are directed at each satoyama landscape as a whole under careful consideration of how landscape elements are connected while taking into account the unique features of each area. Nevertheless, it has become difficult to ensure the continued use and maintenance of terraced rice paddies both in depopulated and suburban satoyama landscapes. The motivation for conserving satoyama landscapes, including those with terraced rice paddies, can be found in the awareness and appreciation of the unique characteristics of each locality that offer opportunities that can only be experienced in that particular area. A satoyama landscape that offers such opportunities allows continuity of traditional practices while integrating necessary changes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Community structure and soil pH determine chemoautotrophic carbon dioxide fixation in drained paddy soils.

PubMed

Long, Xi-En; Yao, Huaiying; Wang, Juan; Huang, Ying; Singh, Brajesh K; Zhu, Yong-Guan

2015-06-16

Previous studies suggested that microbial photosynthesis plays a potential role in paddy fields, but little is known about chemoautotrophic carbon fixers in drained paddy soils. We conducted a microcosm study using soil samples from five paddy fields to determine the environmental factors and quantify key functional microbial taxa involved in chemoautotrophic carbon fixation. We used stable isotope probing in combination with phospholipid fatty acid (PLFA) and molecular approaches. The amount of microbial (13)CO2 fixation was determined by quantification of (13)C-enriched fatty acid methyl esters and ranged from 21.28 to 72.48 ng of (13)C (g of dry soil)(-1), and the corresponding ratio (labeled PLFA-C:total PLFA-C) ranged from 0.06 to 0.49%. The amount of incorporationof (13)CO2 into PLFAs significantly increased with soil pH except at pH 7.8. PLFA and high-throughput sequencing results indicated a dominant role of Gram-negative bacteria or proteobacteria in (13)CO2 fixation. Correlation analysis indicated a significant association between microbial community structure and carbon fixation. We provide direct evidence of chemoautotrophic C fixation in soils with statistical evidence of microbial community structure regulation of inorganic carbon fixation in the paddy soil ecosystem.

Quantifying seasonal variation of leaf area index using near-infrared digital camera in a rice paddy

NASA Astrophysics Data System (ADS)

Hwang, Y.; Ryu, Y.; Kim, J.

2017-12-01

Digital camera has been widely used to quantify leaf area index (LAI). Numerous simple and automatic methods have been proposed to improve the digital camera based LAI estimates. However, most studies in rice paddy relied on arbitrary thresholds or complex radiative transfer models to make binary images. Moreover, only a few study reported continuous, automatic observation of LAI over the season in rice paddy. The objective of this study is to quantify seasonal variations of LAI using raw near-infrared (NIR) images coupled with a histogram shape-based algorithm in a rice paddy. As vegetation highly reflects the NIR light, we installed NIR digital camera 1.8 m above the ground surface and acquired unsaturated raw format images at one-hour intervals between 15 to 80 º solar zenith angles over the entire growing season in 2016 (from May to September). We applied a sub-pixel classification combined with light scattering correction method. Finally, to confirm the accuracy of the quantified LAI, we also conducted direct (destructive sampling) and indirect (LAI-2200) manual observations of LAI once per ten days on average. Preliminary results show that NIR derived LAI agreed well with in-situ observations but divergence tended to appear once rice canopy is fully developed. The continuous monitoring of LAI in rice paddy will help to understand carbon and water fluxes better and evaluate satellite based LAI products.

Performance of duckweed and effective microbes in reducing arsenic in paddy and paddy soil

NASA Astrophysics Data System (ADS)

Ng, C. A.; Wong, L. Y.; Lo, P. K.; Bashir, M. J. K.; Chin, S. J.; Tan, S. P.; Chong, C. Y.; Yong, L. K.

2017-04-01

In this study phytoremediation plant (duckweed) and effective microbes were used to investigate their effectiveness in reducing arsenic concentration in paddy soil and paddy grain. The results show that using duckweed alone is a better choice as it could decrease the arsenic concentration in paddy by 27.697 % and 8.268 % in paddy grain and paddy husk respectively. The study also found out that the concentration of arsenic in soil would affect the performance of duckweed and also delayed the reproduction rate of duckweed. Using the mixture of effective microbes and duckweed together to decrease arsenic in paddy was noticed having the least potential in reducing the arsenic concentration in paddy.

Evaluation of Heavy Metal Exposure to Soil and Paddy Plant around the Closed Municipal Solid Waste Landfill: Case Study at Gunung Tugel Landfill, Banyumas-Central Java

NASA Astrophysics Data System (ADS)

Kasam; Rahmawati, Suphia; Mulya Iresha, Fajri; Wacano, Dhandhun; Farida Fauziah, Ida; Afif Amrullah, Muhammad

2018-01-01

This work was focused on assessing the exposure of heavy metal from closed municipal solid waste (MSW) landfill on soil and paddy plants. This study aimed to determine heavy metal content whether at the soil in the around Gunung Tugel landfill included and accumulated in the paddy plant tissues. The investigated metals include chromium (Cr), copper (Cu), cadmium (Cd), iron (Fe), and zinc (Zn). The samples were acid-digested before the desired elements were measured using Atomic Absorption Spectrophotometry (AAS). The results are presented as distribution map of the landfill area based on the total heavy metals content distribution in the soil and paddy plants. The samples shown that the concentrations of heavy metals around Gunung Tugel landfill are 6.27-34.71 mg/kg, 0.17-0.42 mg/kg, 28.29-48.69 mg/kg, 18,997.26-32,572.29 mg/kg, 342.74-834.49 mg/kg, 136.10-290.14 mg/kg at the top soil and 0.00-1.70 mg/kg, 0.00-0.26 mg/kg, 0.79-10.46 mg/kg, 13.88-61.46 mg/kg, 18.79-50.56 mg/kg, 87.27-273.22 mg/kg at the paddy for Cr, Cd, Cu, Fe, Mn, and Zn respectively. According to the results, The Gunung Tugel landfill is not a direct source of heavy metal pollution at paddy plant in the landfill area, but through surface water and soil media. Rainfall around landfill is quite high ie more 2000 mm/year of rainfall and soil permeability is 1.0 cm/sec.

Evolution of regional to global paddy rice mapping methods: A review

NASA Astrophysics Data System (ADS)

Dong, Jinwei; Xiao, Xiangming

2016-09-01

Paddy rice agriculture plays an important role in various environmental issues including food security, water use, climate change, and disease transmission. However, regional and global paddy rice maps are surprisingly scarce and sporadic despite numerous efforts in paddy rice mapping algorithms and applications. With the increasing need for regional to global paddy rice maps, this paper reviewed the existing paddy rice mapping methods from the literatures ranging from the 1980s to 2015. In particular, we illustrated the evolution of these paddy rice mapping efforts, looking specifically at the future trajectory of paddy rice mapping methodologies. The biophysical features and growth phases of paddy rice were analyzed first, and feature selections for paddy rice mapping were analyzed from spectral, polarimetric, temporal, spatial, and textural aspects. We sorted out paddy rice mapping algorithms into four categories: (1) Reflectance data and image statistic-based approaches, (2) vegetation index (VI) data and enhanced image statistic-based approaches, (3) VI or RADAR backscatter-based temporal analysis approaches, and (4) phenology-based approaches through remote sensing recognition of key growth phases. The phenology-based approaches using unique features of paddy rice (e.g., transplanting) for mapping have been increasingly used in paddy rice mapping. Current applications of these phenology-based approaches generally use coarse resolution MODIS data, which involves mixed pixel issues in Asia where smallholders comprise the majority of paddy rice agriculture. The free release of Landsat archive data and the launch of Landsat 8 and Sentinel-2 are providing unprecedented opportunities to map paddy rice in fragmented landscapes with higher spatial resolution. Based on the literature review, we discussed a series of issues for large scale operational paddy rice mapping.

Mapping paddy rice planting area in rice-wetland coexistent areas through analysis of Landsat 8 OLI and MODIS images

PubMed Central

Zhou, Yuting; Xiao, Xiangming; Qin, Yuanwei; Dong, Jinwei; Zhang, Geli; Kou, Weili; Jin, Cui; Wang, Jie; Li, Xiangping

2016-01-01

Accurate and up-to-date information on the spatial distribution of paddy rice fields is necessary for the studies of trace gas emissions, water source management, and food security. The phenology-based paddy rice mapping algorithm, which identifies the unique flooding stage of paddy rice, has been widely used. However, identification and mapping of paddy rice in rice-wetland coexistent areas is still a challenging task. In this study, we found that the flooding/transplanting periods of paddy rice and natural wetlands were different. The natural wetlands flood earlier and have a shorter duration than paddy rice in the Panjin Plain, a temperate region in China. We used this asynchronous flooding stage to extract the paddy rice planting area from the rice-wetland coexistent area. MODIS Land Surface Temperature (LST) data was used to derive the temperature-defined plant growing season. Landsat 8 OLI imagery was used to detect the flooding signal and then paddy rice was extracted using the difference in flooding stages between paddy rice and natural wetlands. The resultant paddy rice map was evaluated with in-situ ground-truth data and Google Earth images. The estimated overall accuracy and Kappa coefficient were 95% and 0.90, respectively. The spatial pattern of OLI-derived paddy rice map agrees well with the paddy rice layer from the National Land Cover Dataset from 2010 (NLCD-2010). The differences between RiceLandsat and RiceNLCD are in the range of ±20% for most 1-km grid cell. The results of this study demonstrate the potential of the phenology-based paddy rice mapping algorithm, via integrating MODIS and Landsat 8 OLI images, to map paddy rice fields in complex landscapes of paddy rice and natural wetland in the temperate region. PMID:27688742

Mapping paddy rice planting area in rice-wetland coexistent areas through analysis of Landsat 8 OLI and MODIS images.

PubMed

Zhou, Yuting; Xiao, Xiangming; Qin, Yuanwei; Dong, Jinwei; Zhang, Geli; Kou, Weili; Jin, Cui; Wang, Jie; Li, Xiangping

2016-04-01

Accurate and up-to-date information on the spatial distribution of paddy rice fields is necessary for the studies of trace gas emissions, water source management, and food security. The phenology-based paddy rice mapping algorithm, which identifies the unique flooding stage of paddy rice, has been widely used. However, identification and mapping of paddy rice in rice-wetland coexistent areas is still a challenging task. In this study, we found that the flooding/transplanting periods of paddy rice and natural wetlands were different. The natural wetlands flood earlier and have a shorter duration than paddy rice in the Panjin Plain, a temperate region in China. We used this asynchronous flooding stage to extract the paddy rice planting area from the rice-wetland coexistent area. MODIS Land Surface Temperature (LST) data was used to derive the temperature-defined plant growing season. Landsat 8 OLI imagery was used to detect the flooding signal and then paddy rice was extracted using the difference in flooding stages between paddy rice and natural wetlands. The resultant paddy rice map was evaluated with in-situ ground-truth data and Google Earth images. The estimated overall accuracy and Kappa coefficient were 95% and 0.90, respectively. The spatial pattern of OLI-derived paddy rice map agrees well with the paddy rice layer from the National Land Cover Dataset from 2010 (NLCD-2010). The differences between Rice Landsat and Rice NLCD are in the range of ±20% for most 1-km grid cell. The results of this study demonstrate the potential of the phenology-based paddy rice mapping algorithm, via integrating MODIS and Landsat 8 OLI images, to map paddy rice fields in complex landscapes of paddy rice and natural wetland in the temperate region.

Evolution of regional to global paddy rice mapping methods

NASA Astrophysics Data System (ADS)

Dong, J.; Xiao, X.

2016-12-01

Paddy rice agriculture plays an important role in various environmental issues including food security, water use, climate change, and disease transmission. However, regional and global paddy rice maps are surprisingly scarce and sporadic despite numerous efforts in paddy rice mapping algorithms and applications. In this presentation we would like to review the existing paddy rice mapping methods from the literatures ranging from the 1980s to 2015. In particular, we illustrated the evolution of these paddy rice mapping efforts, looking specifically at the future trajectory of paddy rice mapping methodologies. The biophysical features and growth phases of paddy rice were analyzed first, and feature selections for paddy rice mapping were analyzed from spectral, polarimetric, temporal, spatial, and textural aspects. We sorted out paddy rice mapping algorithms into four categories: 1) Reflectance data and image statistic-based approaches, 2) vegetation index (VI) data and enhanced image statistic-based approaches, 3) VI or RADAR backscatter-based temporal analysis approaches, and 4) phenology-based approaches through remote sensing recognition of key growth phases. The phenology-based approaches using unique features of paddy rice (e.g., transplanting) for mapping have been increasingly used in paddy rice mapping. Based on the literature review, we discussed a series of issues for large scale operational paddy rice mapping.

Periphyton: an important regulator in optimizing soil phosphorus bioavailability in paddy fields.

PubMed

Wu, Yonghong; Liu, Junzhuo; Lu, Haiying; Wu, Chenxi; Kerr, Philip

2016-11-01

Periphyton is ubiquitous in paddy field, but its importance in influencing the bioavailability of phosphorus (P) in paddy soil has been rarely recognized. A paddy field was simulated in a greenhouse to investigate how periphyton influences P bioavailability in paddy soil. Results showed that periphyton colonizing on paddy soil greatly reduced P content in paddy floodwater but increased P bioavailability of paddy soil. Specifically, all the contents of water-soluble P (WSP), readily desorbable P (RDP), algal-available P (AAP), and NaHCO 3 -extractable P (Olsen-P) in paddy soil increased to an extent compared to the control (without periphyton) after fertilization. In particular, Olsen-P was the most increased P species, up to 216 mg kg -1 after fertilization, accounting for nearly 60 % of total phosphorus (TP) in soil. The paddy periphyton captured P up to 1.4 mg g -1 with Ca-P as the dominant P fraction and can be a potential crop fertilizer. These findings indicated that the presence of periphyton in paddy field benefited in improving P bioavailability for crops. This study provides valuable insights into the roles of periphyton in P bioavailability and migration in a paddy ecosystem and technical support for P regulation.

Development of bulk density, total C distribution and OC saturation in fine mineral fractions during paddy soil evolution

NASA Astrophysics Data System (ADS)

Wissing, Livia; Kölbl, Angelika; Cao, Zhi-Hong; Kögel-Knabner, Ingrid

2010-05-01

Paddy soils are described as important accumulator for OM (Zhang and He, 2004). In southeast China, paddy soils have the second highest OM stocks (Zhao et al, 1997) and thus a large proportion of the terrestrial carbon is conserved in wetland rice soils. The paddy soil management is believed to be favorable for accumulation of organic matter, as its content in paddy soils is statistically higher than that of non-paddy soils (Cai, 1996). However, the mechanism of OM storage and the development of OM distribution during paddy soil evolution is largely unknown. The aim of the project is to identify the role of organo-mineral complexes for the stabilization of organic carbon during management-induced paddy soil formation in a chronosequence ranging from 50 to 2000 years of paddy soil use. The soil samples were analysed for bulk density, total organic carbon (TOC) and total inorganic carbon (TIC) concentrations of bulk soils and the concentration of organic carbon as well as the organic carbon stocks of physical soil fractions. First results indicate distinctly different depth distributions between paddy and non-paddy (control) sites. The paddy soils are characterized by relatively low bulk densities in the puddled layer (between 0.9 and 1.3 g cm-3) and high values in the plough pan (1.4 to 1.6 g cm-3) and the non-paddy soils by relatively homogeneous values throughout the profiles (1.3 to 1.4 g cm-3). In contrast to the carbonate-rich non-paddy sites, we found a significant loss of carbonates during paddy soil formation, resulting in decalcification of the upper 20 cm after 100 yr of paddy soil use, and decalcification of the total soil profile in 700, 1000 and 2000 yr old paddy soils. The calculation of the organic carbon stocks of each horizon indicate that paddy sites always have higher values in topsoils compared to non-paddy sites, and show increasing values with increasing soil age. The capacity of fine mineral fractions to preserve OC was calculated according to Hassink (1997). The potential capacity of paddy soil fraction to preserve OC is independently from soil age between 30 and 35.4 g OC (kg soil)-1. However, the calculated saturation level increases from 11.7 to 19.9 g OC (kg soil)-1 from 50 to 2000 y old paddy sites respectively. With increasing duration of paddy soil use, the fine fractions indicate an increasing saturation level from 33.1% to 56.2% of the potential capacity to preserve OC. This underlines the importance of fine fractions for increasing OC storage during paddy soil evolution. Conclusively, paddy soil management leads to an accelerated soil development compared to non-irrigated cropland sites. In addition, increasing OC stocks, especially in the fine mineral associated OM fractions underline the relevance of paddy soil management for OC sequestration. References Cai Z. (1996). Effect of land use on organic carbon storage in soils in eastern China. Water Air Soil Pollut 91, 383-393. Hassink J. (1997). The capacity of soil to preserve organic C and N by their association with clay and silt particles. Plant and Soil 191, 77-87. Zhang M., He Z. (2004). Long-term changes in organic carbon and nutrients of an Ultisol under rice cropping in southeast China. Geoderma 118, 167-179. Zhao C. (1996). Effect of land use on organic carbon storage in soils in eastern China. Water Air Soil Pollut 91, 383-393.

Promoting Effects of a Single Rhodopseudomonas palustris Inoculant on Plant Growth by Brassica rapa chinensis under Low Fertilizer Input

PubMed Central

Wong, Wai-Tak; Tseng, Ching-Han; Hsu, Shu-Hua; Lur, Huu-Sheng; Mo, Chia-Wei; Huang, Chu-Ning; Hsu, Shu-Chiung; Lee, Kung-Ta; Liu, Chi-Te

2014-01-01

Several Rhodopseudomonas palustris strains have been isolated from rice paddy fields in Taiwan by combining the Winogradsky column method and molecular marker detection. These isolates were initially screened by employing seed germination and seedling vigor assays to evaluate their potential as inoculants. To fulfill the demand in the present farming system for reducing the application of chemical fertilizers, we assessed the plant growth-promoting effects of the R. palustris YSC3, YSC4, and PS3 inoculants on Brassica rapa chinensis (Chinese cabbage) cultivated under a half quantity of fertilizer. The results obtained showed that supplementation with approximately 4.0×106 CFU g−1 soil of the PS3 inoculant at half the amount of fertilizer consistently produced the same plant growth potential as 100% fertility, and also increased the nitrogen use efficiency of the applied fertilizer nutrients. Furthermore, we noted that the plant growth-promotion rate elicited by PS3 was markedly higher with old seeds than with new seeds, suggesting it has the potential to boost the development of seedlings that were germinated from carry-over seeds of poor quality. These beneficial traits suggest that the PS3 isolate may serve as a potential PGPR inoculant for integrated nutrient management in agriculture. PMID:25130882

Spatial landuse planning using land evaluation and dynamic system to define sustainable area of paddy field: Case study in Karawang Regency, West Java, Indonesia

NASA Astrophysics Data System (ADS)

Widiatmaka, Widiatmaka; Ambarwulan, Wiwin; Firmansyah, Irman; Munibah, Khursatul; Santoso, Paulus B. K.

2015-04-01

Indonesia is the country with the 4th largest population in the worlds; the population reached more than 237 million people. With rice as the staple food for more than 95 percent of the population, there is an important role of paddy field in Indonesian food security. Actually, paddy field in Java has produced 52,6% of the total rice production in Indonesia, showing the very high dependence of Indonesia on food production from paddy fields in Java island. Karawang Regency is one of the regions in West Java Province that contribute to the national food supply, due to its high soil fertility and its high extent of paddy field. Dynamics of land use change in this region are high because of its proximity to urban area; this dynamics has led to paddy field conversion to industry and residential landuse, which in turn change the regional rice production capacity. Decreasing paddy field landuse in this region could be serve as an example case of the general phenomena which occurred in Javanese rice production region. The objective of this study were: (i) to identify the suitable area for paddy field, (ii) to modelize the decreasing of paddy field in socio-economic context of the region, and (iii) to plan the spatial priority area of paddy field protection according to model prediction. A land evaluation for paddy was completed after a soil survey, while IKONOS imagery was analyzed to delineate paddy fields. Dynamic system model of paddy field land use is built, and then based on the model built, the land area of paddy field untill 2040 in some scenarios was developped. The research results showed that the land suitability class for paddy fields in Karawang Regency ranged from very suitable (S1) to marginally suitable (S3), with various land characteristics as limiting factors. The model predicts that if the situation of paddy field land use change continues in its business as usual path, paddy field area that would exist in the region in 2040 will stay half of the recent area. Based on the model, the scenario were developed for the protection of priority area. With such scenario, paddy field remains close to the value predicted oficially. Spatial information then can play a role by presenting the scenario spatially. Combining spatial information with land suitability, priority areas of paddy field protection can be delineated. Policies that followed also then be compiled, including the location of protection. Key-words: Land evaluation, food security, spatial information

Mapping paddy rice distribution using multi-temporal Landsat imagery in the Sanjiang Plain, northeast China

PubMed Central

XIAO, Xiangming; DONG, Jinwei; QIN, Yuanwei; WANG, Zongming

2016-01-01

Information of paddy rice distribution is essential for food production and methane emission calculation. Phenology-based algorithms have been utilized in the mapping of paddy rice fields by identifying the unique flooding and seedling transplanting phases using multi-temporal moderate resolution (500 m to 1 km) images. In this study, we developed simple algorithms to identify paddy rice at a fine resolution at the regional scale using multi-temporal Landsat imagery. Sixteen Landsat images from 2010–2012 were used to generate the 30 m paddy rice map in the Sanjiang Plain, northeast China—one of the major paddy rice cultivation regions in China. Three vegetation indices, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Land Surface Water Index (LSWI), were used to identify rice fields during the flooding/transplanting and ripening phases. The user and producer accuracies of paddy rice on the resultant Landsat-based paddy rice map were 90% and 94%, respectively. The Landsat-based paddy rice map was an improvement over the paddy rice layer on the National Land Cover Dataset, which was generated through visual interpretation and digitalization on the fine-resolution images. The agricultural census data substantially underreported paddy rice area, raising serious concern about its use for studies on food security. PMID:27695637

A satellite-based assessment of the effects of demonetization on the 2016-2017 Indian paddy and wheat agricultural seasons

NASA Astrophysics Data System (ADS)

Lin, M.; Singh, N.; Mueller, N. D.; Huybers, P. J.

2017-12-01

Demonetization invalidated 86% of the currency in circulation in India on November 8, 2016, in the midst of the harvesting and sale of the monsoon kharif paddy or rice crop and the commencement of the winter rabi wheat-growing season. Regions of the Indo-Gangetic Plain, the breadbasket of India, and Northeastern India, the rice bowl, show signatures of satellite-observed vegetation activity consistent with a delayed rice harvest and a delayed wheat sowing, apparent over regions with heavy rice-cropping, wheat-cropping, or both. Compared to previous years, these signatures are anomalous after accounting for the temporal increases in agricultural productivity and for the influence of the preceding monsoon rainfall. Delays in the crop production calendar can be expected from the lack of cash, as both labor and inputs such as seed, fuel, fertilizer, machine rentals, are paid in cash for the rural population, the majority of whom do not have regular access to banking. Although 2016-2017 boasted a strong monsoon and subsequently high and even record productivity, the overall production figures could mask heterogeneity in farmers' ability to recoup their investments as a function of their financial access.

Soil type-depending effect of paddy management: composition and distribution of soil organic matter

NASA Astrophysics Data System (ADS)

Urbanski, Livia; Kölbl, Angelika; Lehndorff, Eva; Houtermans, Miriam; Schad, Peter; Zhang, Gang-Lin; Rahayu Utami, Sri; Kögel-Knabner, Ingrid

2016-04-01

Paddy soil management is assumed to promote soil organic matter accumulation and specifically lignin caused by the resistance of the aromatic lignin structure against biodegradation under anaerobic conditions during inundation of paddy fields. The present study investigates the effect of paddy soil management on soil organic matter composition compared to agricultural soils which are not used for rice production (non-paddy soils). A variety of major soil types, were chosen in Indonesia (Java), including Alisol, Andosol and Vertisol sites (humid tropical climate of Java, Indonesia) and in China Alisol sites (humid subtropical climate, Nanjing). This soils are typically used for rice cultivation and represent a large range of soil properties to be expected in Asian paddy fields. All topsoils were analysed for their soil organic matter composition by solid-state 13C nuclear magnetic resonance spectroscopy and lignin-derived phenols by CuO oxidation method. The soil organic matter composition, revealed by solid-state 13C nuclear magnetic resonance, was similar for the above named different parent soil types (non-paddy soils) and was also not affected by the specific paddy soil management. The contribution of lignin-related carbon groups to total SOM was similar in the investigated paddy and non-paddy soils. A significant proportion of the total aromatic carbon in some paddy and non-paddy soils was attributed to the application of charcoal as a common management practise. The extraction of lignin-derived phenols revealed low VSC (vanillyl, syringyl, cinnamyl) values for all investigated soils, being typical for agricultural soils. An inherent accumulation of lignin-derived phenols due to paddy management was not found. Lignin-derived phenols seem to be soil type-dependent, shown by different VSC concentrations between the parent soil types. The specific paddy management only affects the lignin-derived phenols in Andosol-derived paddy soils which are characterized by significantly higher VSC values compared to their parent soil types. However, the higher organic carbon concentrations in Andosol and Alisol (China)-derived paddy soils compared to their parent soil types, could not be explained by an enrichment of lignin-derived phenols. It seems that site specific incorporation of crop residues and properties of the parent soil types are likely more important for organic carbon contents and soil organic matter composition than the effect of paddy management itself.

Photolytic and photocatalytic degradation of quinclorac in ultrapure and paddy field water: identification of transformation products and pathways.

PubMed

Pareja, Lucía; Pérez-Parada, Andrés; Agüera, Ana; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, Amadeo R

2012-05-01

Quinclorac (QNC) is an effective but rather persistent herbicide commonly used in rice production. This herbicide presents a mean persistence in the environment so its residues are considered of environmental relevance. However, few studies have been conducted to investigate its environmental behavior and degradation. In the present work, direct photolysis and TiO(2) photocatalysis of the target compound in ultrapure and paddy field water were investigated. After 10h photolysis in ultrapure water, the concentration of QNC declined 26% and 54% at 250 and 700 W m(-2), respectively. However, the amount of quinclorac in paddy field water remained almost constant under the same irradiation conditions. QNC dissipated completely after 40 min of TiO(2) photocatalysis in ultrapure water, whereas 130 min were necessary to degrade 98% of the initial concentration in paddy field water. Possible QNC photolytic and photocatalytic degradation pathways are proposed after structure elucidation of the main transformation products, through liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry and exact mass measurements. Pyridine ring hydroxylation at C-9 followed by ring opening and/or oxidative dechlorination were the key steps of QNC degradation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effect of ferrihydrite biomineralization on methanogenesis in an anaerobic incubation from paddy soil

NASA Astrophysics Data System (ADS)

Zhuang, Li; Xu, Jielong; Tang, Jia; Zhou, Shungui

2015-05-01

Microbial reduction of Fe(III) can be one of the major factors controlling methane production from anaerobic sedimentary environments, such as paddy soils and wetlands. Although secondary iron mineralization following Fe(III) reduction is a process that occurs naturally over time, it has not yet been considered in methanogenic systems. This study performed a long-term anaerobic incubation of a paddy soil and ferrihydrite-supplemented soil cultures to investigate methanogenesis during ferrihydrite biomineralization. The results revealed that the long-term effect of ferrihydrite on methanogenesis may be enhancement rather than suppression documented in previous studies. During initial microbial ferrihydrite reduction, methanogenesis was suppressed; however, the secondary minerals of magnetite formation was simultaneous with facilitated methanogenesis in terms of average methane production rate and acetate utilization rate. In the phase of magnetite formation, microbial community analysis revealed a strong stimulation of the bacterial Geobacter, Bacillus, and Sedimentibacter and the archaeal Methanosarcina in the ferrihydrite-supplemented cultures. Direct electric syntrophy between Geobacter and Methanosarcina via conductive magnetite is the plausible mechanism for methanogenesis acceleration along with magnetite formation. Our data suggested that a change in iron mineralogy might affect the conversion of anaerobic organic matter to methane and might provide a fresh perspective on the mitigation of methane emissions from paddy soils by ferric iron fertilization.

Evaluation of evapotranspiration on paddy rice using non-weighting lysimeters under the different air temperature

NASA Astrophysics Data System (ADS)

Oh, D.; Ryu, J. H.; Cho, J.

2017-12-01

Estimation of the crop evapotranspiration (ETc), as a representative of crop water needs, is important for not only high crop productivity, but also improving irrigation water management. In farm lands crop coefficient (Kc), the ratio of ETc to potential ET, is often used to simply estiamte ETc. However, the traits of Kc under the global warming condition will different with current one because plant transpiration and surface evaporaiton will be changed by the alternative crop growth and evaporative energy. In this study, Non-Weighting Lysimeter (NWL) was used to directly estimate ETc under the warmed condition, particularly for paddy riace which has one of lower water use efficiency. The different air t emperature (Ta) conditions for the NWL were provided by Temperature Gradient Chamber (TGC), which was formed gradually warmed conditions. The water body evporation and paddy rice evapotransipiration in the NWL were at the two places of ambient Ta (AT) and AT+3° in the TGC. In addition, we installed Infra-Red thermometer (IRT) to understand the surface energy balance. The result was shown that the different partitioning of evaporation and transpiration of paddy rice at the AT+3°, comparing at AT. Further, the water use efficiency, the ratio of yield to total ET, was also decreased in the warmed condition. These experiments for paddy rice ET in the warmed conditions during growth period will be useful to understand the effect of global warming on the hydrological cycle and manamge the irrigation schedule for more efficient water use.

Lignin decomposition and microbial community in paddy soils: effects of alternating redox conditions

NASA Astrophysics Data System (ADS)

Cerli, Chiara; Liu, Qin; Hanke, Alexander; Kaiser, Klaus; Kalbitz, Karsten

2013-04-01

Paddy soils are characterised by interchanging cycles of anaerobic and aerobic conditions. Such fluctuations cause continuous changes in soil solution chemistry as well as in the composition and physiological responses of the microbial community. Temporary deficiency in oxygen creates conditions favourable to facultative or obligates anaerobic bacteria, while aerobic communities can thrive in the period of water absence. These alterations can strongly affect soil processes, in particular organic matter (OM) accumulation and mineralization. In submerged soils, lignin generally constitutes a major portion of the total OM because of hampered degradation under anoxic conditions. The alternating redox cycles resulting from paddy soil management might promote both degradation and preservation of lignin, affecting the overall composition and reactivity of total and dissolved OM. We sampled soils subjected to cycles of anoxic (rice growing period) and oxic (harvest and growth of other crops) conditions since 700 and 2000 years. We incubated suspended Ap material, sampled from the two paddy plus two corresponding non-paddy control soils under oxic and anoxic condition, for 3 months, interrupted by a short period of three weeks (from day 21 to day 43) with reversed redox conditions. At each sampling time (day 2, 21, 42, 63, 84), we determined lignin-derived phenols (by CuO oxidation) as well as phospholipids fatty acids contents and composition. We aimed to highlight changes in lignin decomposition as related to the potential rapid changes in microbial community composition. Since the studied paddy soils had a long history of wet rice cultivation, the microbial community should be well adapted to interchanging oxic and anoxic cycles, therefore fully expressing its activity at both conditions. In non-paddy soil changes in redox conditions caused modification of quantity and composition of the microbial community. On the contrary, in well-established paddy soils the microbial community appeared to be affected by alternating redox conditions more in quantity that in quality. Bacteria represented the largest portion of the living microorganisms, responding promptly to changes in soil redox status. However we did not detect any sign of lignin biodegradation. Relative short (3 weeks) changes in redox conditions had no effect on lignin decomposition or oxidation state. Also, lignin was not altered during oxic incubation. Since fungi represented only small portion of the microbial biomass in the studied soils, they were obviously not capable to cause much degradation, even under favourable conditions. On the contrary, changes in redox conditions strongly affected lignin extractability, regardless of the initial content and direction of change in both paddy and non-paddy soils. This was likely a result of (partial) dissolution and/or pH-induced changes of the surface properties of Fe and Mn hydrous oxides causing the release of mineral-associated lignin-derived phenols. Thus, we speculate that oxidised lignin fragments produced during the (oxic) dry period do not remain in the soils but percolate with water drainage during the flooding period.

Effects of paddy rice agriculture on the seasonal dynamics of atmospheric methane concentration

NASA Astrophysics Data System (ADS)

Zhang, G.; Xiao, X.; Dong, J.; Zhang, Y.; Xin, F.; Zhou, Y.; Wang, J.; Wu, X.; Moore, B., III

2017-12-01

Methane (CH4) is an important greenhouse gas (GHG) and may account for 20 % of anticipated global warming. The atmospheric CH4 concentration was nearly constant from 1999 to 2006, following with a strong growth resumed since 2007. Previous study attributed the increase in CH4 to agriculture. Specifically, paddy rice agriculture is a significant source of CH4, but large uncertainty still exists on methane emission estimates from rice paddies, largely due to lack of detailed geospatial datasets of rice paddies. In this study, based on a pixel- and phenology-based image analysis system with multi-temporal MODIS imagery (MODIS-RICE), we generated the paddy rice map in 2005 to document the spatiotemporal pattern of paddy rice dynamics in Monsoon Asia, which accounts for more than 90% of the global rice production. Furthermore, we examined the effects of paddy rice agriculture on atmospheric CH4 concentration over Monsoon Asia, by comparing atmospheric CH4 concentration data from SCIAMACHY sensor and the paddy rice maps in 2005. We found a significant spatial consistency between spatial patterns of paddy rice and atmospheric CH4 concentration. Based on the high resolution paddy rice map, different seasonal dynamics of CH4 concentration, including single, double to triple peaks, were found based on the rice paddy distribution information. That suggests paddy rice agriculture contributes substantially to the spatial and seasonal pattern of atmospheric CH4 concentration in Monsoon Asia. This study provides satellite evidence for seasonal cycle of CH4 dynamics at regional scale, and suggests that shifting regime of paddy rice agriculture and cropping intensity could affect the seasonal dynamics and spatial pattern of atmospheric methane concentration.

Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography-quadrupole-linear ion trap-mass spectrometry.

PubMed

Pareja, Lucía; Martínez-Bueno, M J; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, A R

2011-07-29

A multiresidue method was developed for the quantification and confirmation of 70 pesticides in paddy field water. After its filtration, water was injected directly in a liquid chromatograph coupled to a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). The list of target analytes included organophosphates, phenylureas, sulfonylureas, carbamates, conazoles, imidazolinones and others compounds widely used in different countries where rice is cropped. Detection and quantification limits achieved were in the range from 0.4 to 80 ng L(-1) and from 2 to 150 ng L(-1), respectively. Correlation coefficients for the calibration curves in the range 0.1-50 μg L(-1) were higher than 0.99 except for diazinon (0.1-25 μg L(-1)). Only 9 pesticides presented more than 20% of signal suppression/enhancement, no matrix effect was observed in the studied conditions for the rest of the target pesticides. The method developed was used to investigate the occurrence of pesticides in 59 water samples collected in paddy fields located in Spain and Uruguay. The study shows the presence of bensulfuron methyl, tricyclazole, carbendazim, imidacloprid, tebuconazole and quinclorac in a concentration range from 0.08 to 7.20 μg L(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

Diversity and activity of nitrogen fixing archaea and bacteria associated with micro-environments of wetland rice

NASA Astrophysics Data System (ADS)

Schmidt, Hannes; Woebken, Dagmar

2017-04-01

Wetland rice is one of the world's most important crop plants. The cultivation on waterlogged paddy soils is strongly limited by nitrogen (N), which is typically supplied by industrial fertilizers that are not only costly but also exhibit hazardous effects on the environment. It has been reported that "Biological Nitrogen Fixation" through N2-fixing bacteria and archaea (diazotrophs) can alleviate the N-shortage in rice cultivation, thus carrying out an important ecosystem function. However, our understanding of the diversity and in situ N2 fixation activity of diazotrophs in flooded rice fields is still rudimentary. Moreover, knowledge on the impact of biochemical gradients established by root activity (i.e. exudation, radial oxygen loss) on the functioning of N-fixing microorganisms in paddy soil ecosystems is limited. We aimed at studying underlying processes on biologically relevant scales. Greenhouse studies were performed to identify key factors that control rice-diazotroph association and related N2 fixation activities. Paddy soils of different geographical origin were cultivated with two commercially used genotypes of wetland rice. Samples were separated into bulk soil, rhizosphere soil, rhizoplane, and roots at flowering stage of rice plant development. These samples were subjected to functional assays and various molecular biological techniques in order to analyze the associated diazotroph communities. Based on Illumina amplicon sequencing of nifH genes and transcripts, we show that the diversity and potential activity of diazotroph communities varies according to micro-environments. We will comparatively discuss the influence of (a) the soil microbial "seed bank" and (b) plant genotype in shaping the respective microbiomes and selecting for potentially active diazotrophs. Actual N2 fixation activities of soil-genotype combinations and micro-environments will be shown on the basis of incubation assays using 15N2-containing atmospheres. Areas of potential N-transfer between diazotrophs and rice roots will be presented via the detection and visualization of spatial colonization patterns of selected diazotrophic groups on rice rhizoplanes. Our approach will help to increase the understanding of the contribution of Biological Nitrogen Fixation to rice cultivation in paddy soil ecosystems.

Testing estimation of water surface in Italian rice district from MODIS satellite data

NASA Astrophysics Data System (ADS)

Ranghetti, Luigi; Busetto, Lorenzo; Crema, Alberto; Fasola, Mauro; Cardarelli, Elisa; Boschetti, Mirco

2016-10-01

Recent changes in rice crop management within Northern Italy rice district led to a reduction of seeding in flooding condition, which may have an impact on reservoir water management and on the animal and plant communities that depend on the flooded paddies. Therefore, monitoring and quantifying the spatial and temporal variability of water presence in paddy fields is becoming important. In this study we present a method to estimate dynamics of presence of standing water (i.e. fraction of flooded area) in rice fields using MODIS data. First, we produced high resolution water presence maps from Landsat by thresholding the Normalised Difference Flood Index (NDFI) made: we made it by comparing five Landsat 8 images with field-obtained information about rice field status and water presence. Using these data we developed an empirical model to estimate the flooding fraction of each MODIS cell. Finally we validated the MODIS-based flooding maps with both Landsat and ground information. Results showed a good predictability of water surface from Landsat (OA = 92%) and a robust usability of MODIS data to predict water fraction (R2 = 0.73, EF = 0.57, RMSE = 0.13 at 1 × 1 km resolution). Analysis showed that the predictive ability of the model decreases with the greening up of rice, so we used NDVI to automatically discriminate estimations for inaccurate cells in order to provide the water maps with a reliability flag. Results demonstrate that it is possible to monitor water dynamics in rice paddies using moderate resolution multispectral satellite data. The achievement is a proof of concept for the analysis of MODIS archives to investigate irrigation dynamics in the last 15 years to retrieve information for ecological and hydrological studies.

Novel groups and unique distribution of phage phoH genes in paddy waters in northeast China

PubMed Central

Wang, Xinzhen; Liu, Junjie; Yu, Zhenhua; Jin, Jian; Liu, Xiaobing; Wang, Guanghua

2016-01-01

Although bacteriophages are ubiquitous in various environments, their genetic diversity is primarily investigated in pelagic marine environments. Corresponding studies in terrestrial environments are few. In this study, we conducted the first survey of phage diversity in the paddy ecosystem by targeting a new viral biomarker gene, phoH. A total of 424 phoH sequences were obtained from four paddy waters generated from a pot experiment with different soils collected from open paddy fields in northeast China. The majority of phoH sequences in paddy waters were novel, with the highest identity of ≤70% with known phoH sequences. Four unique groups (Group α, Group β, Group γ and Group δ) and seven new subgroups (Group 2b, Group 3d, Group 3e, Group 6a, Group 6b, Group 6c and Group 6d) were formed exclusively with the clones from the paddy waters, suggesting novel phage phoH groups exist in the paddy ecosystem. Additionally, the distribution proportions of phoH clones in different groups varied among paddy water samples, suggesting the phage community in paddy fields is biogeographically distributed. Furthermore, non-metric multidimensional scaling analysis indicated that phage phoH assemblages in paddy waters were distinct from those in marine waters. PMID:27910929

Annual Changes of Paddy Rice Planting Areas in Northeastern Asia from MODIS images in 2000-2014

NASA Astrophysics Data System (ADS)

Xiao, X.; Zhang, G.; Dong, J.; Menarguez, M. A.; Kou, W.; Jin, C.; Qin, Y.; Zhou, Y.; Wang, J.; Moore, B., III

2014-12-01

Knowledge of the area and spatial distribution of paddy rice is important for assessment of food security, management of water resources, estimation of greenhouse gas (methane) emissions, and understanding avian influenza virus transmission. Over the past two decades, paddy rice cultivation has expanded northward in temperate and cold temperate zones, particularly in Northeastern China. There is a need to quantify and map changes in paddy rice planting areas in Northeastern Asia (Japan, North and South Korea, and northeast China) at annual interval. We developed a pixel- and phenology-based image analysis system, MODIS-RICE, to map the paddy rice in Northeastern Asia by using multi-temporal MODIS thermal and surface reflectance imagery. Paddy rice fields during the flooding and transplanting phases have unique physical and spectral characteristics, which make it possible for the development of an automated and robust algorithm to track flooding and transplanting phases of paddy rice fields over time. In this presentation, we will show the MODIS-based annual maps of paddy rice planting area in the Northeastern Asia from 2000-2014 (500-m spatial resolution). Accuracy assessments using high-resolution images show that the resultant paddy rice map of Northeastern Asia had a comparable accuracy to the existing products, including 2010 Landsat-based National Land Cover Dataset (NLCD) of China, the 2010 RapidEye-based paddy rice map in North Korea, and the 2010 AVNIR-2-based National Land Cover Dataset in Japan in terms of both area and spatial pattern of paddy rice. This study has demonstrated that our novel MODIS-Rice system, which use both thermal and optical MODIS data over a year, are simple and robust tools to identify and map paddy rice fields in temperate and cold temperate zones.

Integration of logistic regression and multicriteria land evaluation to simulation establishment of sustainable paddy field zone in Indramayu Regency, West Java Province, Indonesia

NASA Astrophysics Data System (ADS)

Nahib, Irmadi; Suryanta, Jaka; Niedyawati; Kardono, Priyadi; Turmudi; Lestari, Sri; Windiastuti, Rizka

2018-05-01

Ministry of Agriculture have targeted production of 1.718 million tons of dry grain harvest during period of 2016-2021 to achieve food self-sufficiency, through optimization of special commodities including paddy, soybean and corn. This research was conducted to develop a sustainable paddy field zone delineation model using logistic regression and multicriteria land evaluation in Indramayu Regency. A model was built on the characteristics of local function conversion by considering the concept of sustainable development. Spatial data overlay was constructed using available data, and then this model was built upon the occurrence of paddy field between 1998 and 2015. Equation for the model of paddy field changes obtained was: logit (paddy field conversion) = - 2.3048 + 0.0032*X1 – 0.0027*X2 + 0.0081*X3 + 0.0025*X4 + 0.0026*X5 + 0.0128*X6 – 0.0093*X7 + 0.0032*X8 + 0.0071*X9 – 0.0046*X10 where X1 to X10 were variables that determine the occurrence of changes in paddy fields, with a result value of Relative Operating Characteristics (ROC) of 0.8262. The weakest variable in influencing the change of paddy field function was X7 (paddy field price), while the most influential factor was X1 (distance from river). Result of the logistic regression was used as a weight for multicriteria land evaluation, which recommended three scenarios of paddy fields protection policy: standard, protective, and permissive. The result of this modelling, the priority paddy fields for protected scenario were obtained, as well as the buffer zones for the surrounding paddy fields.

Soil removal as a decontamination practice and radiocesium accumulation in tadpoles in rice paddies at Fukushima.

PubMed

Sakai, Masaru; Gomi, Takashi; Nunokawa, Masanori; Wakahara, Taeko; Onda, Yuichi

2014-04-01

We investigated the biological accumulation of radiocesium in tadpoles [Rana (Pelophylax) porosa porosa] in rice paddies with and without decontamination practice at Fukushima. Radiocesium was accumulated in surface part of soils both in the control and decontaminated paddies one year after decontamination. Mean (134)Cs and (137)Cs concentrations in tadpoles in the control and decontaminated paddies were 3000 and 4500, and 600 and 890 Bq/kg dry weight, respectively. Radiocesium concentrations in surface soil (0-5 cm depth) and tadpoles in the decontaminated paddy were five times smaller than in the control paddy. These results suggest that decontamination practice can reduce radiocesium concentrations in both soil and tadpoles. However, at the decontaminated paddy, radiocesium concentrations in surface soils became 3.8 times greater one year after decontamination, which indicates that monitoring the subsequent movement of radiocesium in rice paddies and surrounding areas is essential for examining contamination propagation. Copyright © 2014 Elsevier Ltd. All rights reserved.

A new method for indirectly estimating infiltration of paddy fields in situ

NASA Astrophysics Data System (ADS)

Xu, Yunqiang; Su, Baolin; Wang, Hongqi; He, Jingyi

2018-06-01

Infiltration is one of the major procedures in water balance research and pollution load estimation in paddy fields. In this study, a new method for indirectly estimating infiltration of paddy fields in situ was proposed and implemented in Taihu Lake basin. Since when there were no rainfall, irrigation and artificial drainage, the water depth variation process of a paddy field is only influenced by evapotranspiration and infiltration (E + F). Firstly, (E + F) was estimated by deciding the steady decreasing rate of water depth; then the evapotranspiration (ET) of the paddy field was calculated by using the crop coefficient method with the recommended FAO-56 Penman-Monteith equation; finally, the infiltration of the paddy field was obtained by subtracting ET from (E + F). Results show that the mean infiltration of the studied paddy field during rice jointing-booting period was 7.41 mm day-1, and the mean vertical infiltration and lateral seepage of the paddy field were 5.46 and 1.95 mm day-1 respectively.

Solubility and leaching risks of organic carbon in paddy soils as affected by irrigation managements.

PubMed

Xu, Junzeng; Yang, Shihong; Peng, Shizhang; Wei, Qi; Gao, Xiaoli

2013-01-01

Influence of nonflooding controlled irrigation (NFI) on solubility and leaching risk of soil organic carbon (SOC) were investigated. Compared with flooding irrigation (FI) paddies, soil water extractable organic carbon (WEOC) and dissolved organic carbon (DOC) in NFI paddies increased in surface soil but decreased in deep soil. The DOC leaching loss in NFI field was 63.3 kg C ha⁻¹, reduced by 46.4% than in the FI fields. It indicated that multi-wet-dry cycles in NFI paddies enhanced the decomposition of SOC in surface soils, and less carbon moved downward to deep soils due to less percolation. That also led to lower SOC in surface soils in NFI paddies than in FI paddies, which implied that more carbon was released into the atmosphere from the surface soil in NFI paddies. Change of solubility of SOC in NFI paddies might lead to potential change in soil fertility and sustainability, greenhouse gas emission, and bioavailability of trace metals or organic pollutants.

Biodegradation of vegetable and agrowastes by Pleurotus sapidus: a novel strategy to produce mushroom with enhanced yield and nutrition.

PubMed

Singh, M P; Singh, V K

2012-12-22

Edible oyster mushroom Pleurotus sapidus was cultivated, on pea pod shell, cauliflower leaves, radish leaves, brassica straw in various combinations of paddy straw. The mushroom failed to grow on these vegetable wastes separately. However, it grew very well on these vegetable wastes when mixed with various combinations of paddy straw as substrate. Total yield and biological efficiency of the mushroom cultivated on substrate containing 20% and 30% vegetable wastes mixed with 70% and 80% (w/w) of paddy straw was found to be better, when compared with yield and efficiency obtained with paddy straw alone (100%). The protein content in the fruit bodies was found to be higher in the mushroom grown on paddy straw mixed with vegetable wastes than that obtained with paddy straw alone. Similarly, six amino acids (Leu, Ile, Val, Thr, Met and Phe) showed a significant increase when the mushroom was grown on a mixed substrate containing both vegetable wastes and paddy straw. On the contrary, the total sugar and reducing sugar content declined in the mushroom grown on the mixture of paddy straw and other wastes, when compared with the results obtained with paddy straw alone.

Effects of long-term pig manure application on antibiotics, abundance of antibiotic resistance genes (ARGs), anammox and denitrification rates in paddy soils.

PubMed

Rahman, M Mizanur; Shan, Jun; Yang, Pinpin; Shang, Xiaoxia; Xia, Yongqiu; Yan, Xiaoyuan

2018-05-09

Previous studies of long-term manure applications in paddy soil mostly focused on the effects on denitrification, occurrence of antibiotics and antibiotic resistance genes (ARGs) without considering the effects on anaerobic ammonium oxidation (anammox). Here, we investigated the potential rates of anammox and denitrification, occurrence of antibiotics and AGRs in response to three fertilization regimes (C, no fertilizer; N, mineral fertilizer; and NM, N plus pig manure) in six long-term paddy experiment sites across China. The potential rates of anammox (0.11-3.64 nmol N g -1 h -1 ) and denitrification (1.5-29.05 nmol N g -1 h -1 ) were correlated with the abundance of anammox genes (hzsB) and denitrification functional genes (narG, nirK, nirS and nosZ), respectively. The anammox and denitrification rates were affected by soil organic carbon (SOC) and significantly (p < 0.05) increased in NM treatments relative to those in N treatments. Although pig manure application increased antibiotic concentrations and abundance of ARGs compared with N treatments, the increased antibiotics did not directly affect the anammox and denitrification rates. Our results suggested that long-term pig manure application significantly increased antibiotic concentrations, abundance of ARGs, and rates of anammox and denitrification, and that the effects of pig manure-derived antibiotics on anammox and denitrification were marginal. This is the first report that investigates the effects of long-term pig manure application on anammox in paddy soils. More attention should be paid to the potential ecological risk of increased ARGs caused by pig manure application in paddy soils. Copyright © 2018 Elsevier Ltd. All rights reserved.

Soil aggregate and organic carbon distribution at dry land soil and paddy soil: the role of different straws returning.

PubMed

Huang, Rong; Lan, Muling; Liu, Jiang; Gao, Ming

2017-12-01

Agriculture wastes returning to soil is one of common ways to reuse crop straws in China. The returned straws are expected to improve the fertility and structural stability of soil during the degradation of straw it selves. The in situ effect of different straw (wheat, rice, maize, rape, and broad bean) applications for soil aggregate stability and soil organic carbon (SOC) distribution were studied at both dry land soil and paddy soil in this study. Wet sieving procedures were used to separate soil aggregate sizes. Aggregate stability indicators including mean weight diameter, geometric mean diameter, mean weight of specific surface area, and the fractal dimension were used to evaluate soil aggregate stability after the incubation of straws returning. Meanwhile, the variation and distribution of SOC in different-sized aggregates were further studied. Results showed that the application of straws, especially rape straw at dry land soil and rice straw at paddy soil, increased the fractions of macro-aggregate (> 0.25 mm) and micro-aggregate (0.25-0.053 mm). Suggesting the nutrients released from straw degradation promotes the growing of soil aggregates directly and indirectly. The application of different straws increased the SOC content at both soils and the SOC mainly distributed at < 0.53 mm aggregates. However, the contribution of SOC in macro- and micro-aggregates increased. Straw-applied paddy soil have a higher total SOC content but lower SOC contents at > 0.25 and 0.25-0.053 mm aggregates with dry land soil. Rape straw in dry land and rice straw in paddy field could stabilize soil aggregates and increasing SOC contents best.

Using eDNA to detect the distribution and density of invasive crayfish in the Honghe-Hani rice terrace World Heritage site

PubMed Central

Yang, Chunyan; Wang, Lin; Wang, Wenzhi; Zhao, Guigang; Geng, Yupeng; Yu, Douglas W.

2017-01-01

The Honghe-Hani landscape in China is a UNESCO World Natural Heritage site due to the beauty of its thousands of rice terraces, but these structures are in danger from the invasive crayfish Procambarus clarkii. Crayfish dig nest holes, which collapse terrace walls and destroy rice production. Under the current control strategy, farmers self-report crayfish and are issued pesticide, but this strategy is not expected to eradicate the crayfish nor to prevent their spread since farmers are not able to detect small numbers of crayfish. Thus, we tested whether environmental DNA (eDNA) from paddy-water samples could provide a sensitive detection method. In an aquarium experiment, Real-time Quantitative polymerase chain reaction (qPCR) successfully detected crayfish, even at a simulated density of one crayfish per average-sized paddy (with one false negative). In a field test, we tested eDNA and bottle traps against direct counts of crayfish. eDNA successfully detected crayfish in all 25 paddies where crayfish were observed and in none of the 7 paddies where crayfish were absent. Bottle-trapping was successful in only 68% of the crayfish-present paddies. eDNA concentrations also correlated positively with crayfish counts. In sum, these results suggest that single samples of eDNA are able to detect small crayfish populations, but not perfectly. Thus, we conclude that a program of repeated eDNA sampling is now feasible and likely reliable for measuring crayfish geographic range and for detecting new invasion fronts in the Honghe Hani landscape, which would inform regional control efforts and help to prevent the further spread of this invasive crayfish. PMID:28505200

Using eDNA to detect the distribution and density of invasive crayfish in the Honghe-Hani rice terrace World Heritage site.

PubMed

Cai, Wang; Ma, Zhuxin; Yang, Chunyan; Wang, Lin; Wang, Wenzhi; Zhao, Guigang; Geng, Yupeng; Yu, Douglas W

2017-01-01

The Honghe-Hani landscape in China is a UNESCO World Natural Heritage site due to the beauty of its thousands of rice terraces, but these structures are in danger from the invasive crayfish Procambarus clarkii. Crayfish dig nest holes, which collapse terrace walls and destroy rice production. Under the current control strategy, farmers self-report crayfish and are issued pesticide, but this strategy is not expected to eradicate the crayfish nor to prevent their spread since farmers are not able to detect small numbers of crayfish. Thus, we tested whether environmental DNA (eDNA) from paddy-water samples could provide a sensitive detection method. In an aquarium experiment, Real-time Quantitative polymerase chain reaction (qPCR) successfully detected crayfish, even at a simulated density of one crayfish per average-sized paddy (with one false negative). In a field test, we tested eDNA and bottle traps against direct counts of crayfish. eDNA successfully detected crayfish in all 25 paddies where crayfish were observed and in none of the 7 paddies where crayfish were absent. Bottle-trapping was successful in only 68% of the crayfish-present paddies. eDNA concentrations also correlated positively with crayfish counts. In sum, these results suggest that single samples of eDNA are able to detect small crayfish populations, but not perfectly. Thus, we conclude that a program of repeated eDNA sampling is now feasible and likely reliable for measuring crayfish geographic range and for detecting new invasion fronts in the Honghe Hani landscape, which would inform regional control efforts and help to prevent the further spread of this invasive crayfish.

Temporal changes of radiocesium in irrigated paddy fields and its accumulation in rice plants in Fukushima.

PubMed

Yang, Baolu; Onda, Yuichi; Wakiyama, Yoshifumi; Yoshimura, Kazuya; Sekimoto, Hitoshi; Ha, Yiming

2016-01-01

About half of the total paddy field area, which is the dominant agricultural land in Fukushima Prefecture, was contaminated by radiocesium released by the Fukushima Daiichi Nuclear Power Plant accident. In this study, we investigated the temporal changes of radiocesium in soil, irrigation water, and rice plant in two adjacent rice paddies, with and without surface-soil-removal, in Fukushima Prefecture for over three years (2012-2014) after the nuclear accident. Our results showed that radiocesium migrated into 24-28 cm soil layers and that the activity concentration of radiocesium in paddy soils showed a significant reduction in 2014. The newly added radiocesium to paddies through irrigation water contributed only a maximum value of 0.15% and 0.75% of the total amount present in control and decontaminated paddies, respectively, throughout the study period. The radiocesium activity concentration in suspended sediment in irrigation water exponentially decreased, and the effective half-lives (Teff) for (137)Cs and (134)Cs were 1.3 and 0.9 years, respectively. Additionally, the average suspended sediment concentration in irrigation water increased between 2012 and 2014, suggesting that enhanced soil erosion had occurred in the surrounding environment. Radiocesium accumulation in rice plant also decreased with time in both paddies. However, the concentration ratio of radiocesium for rice plant in the decontaminated paddy increased compared with control paddy, despite approximately 96% of fallout radiocesium removed in paddy soil. Further analysis is required to clarify the reasons of high concentration ratio of radiocesium for rice plant in the decontaminated paddy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of CH4 Emission from Rice Paddy Soils between Coastal Zone and Inland Regions

NASA Astrophysics Data System (ADS)

Sun, M.; Li, X.

2016-12-01

Numerous measurements of methane (CH4) emission fluxes have been carried out in rice paddy soil between coastal zone and inland regions. However, the differences of CH4 emission from rice paddy soils in these two locations were unavailable. A database of CH4 emission in paddy rice was compiled from previous published references and field observations with major parameters including water regimes, fertilizer application, CH4 fluxes, and environmental variables. Results showed that CH4 emission from inland paddy fields was significantly higher than that in the coastal zone (p < 0.05). Fertilizer application and water management played an important role in CH4 emission. The application of organic fertilizer and continuous flooding significantly promoted CH4 emission from paddy fields. CH4 fluxes showed significantly positive correlations with organic matter, total nitrogen, available potassium and annual temperature (R2 = 0.39, 0.53, 0.27 and 0.23, p < 0.05), and negative correlations with pH and available phosphorus (R2 = 0.29 and 0.37, p < 0.05). Significant differences occurred in available potassium between inland and coastal rice paddy (p < 0.05), which might account for the difference of CH4 emission between inland and coastal rice paddy. The contrasting of CH4 fluxes between inland and coastal wetlands could improve our understanding of the roles of rice paddies in the regional CH4 regulation. Our results also have implications for informing rice paddy management and climate change policy making the efforts being made by agricultural organizations and enterprises to restore coastal rice paddies for mitigating CH4 emissions.

Impact of S fertilizers on pore-water Cu dynamics and transformation in a contaminated paddy soil with various flooding periods.

PubMed

Yang, Jianjun; Zhu, Shenhai; Zheng, Cuiqing; Sun, Lijuan; Liu, Jin; Shi, Jiyan

2015-04-09

Impact of S fertilization on Cu mobility and transformation in contaminated paddy soils has been little reported. In this study, we investigated the dynamics and transformation of dissolved and colloidal Cu in the pore water of a contaminated paddy soil after applying ammonium sulphate (AS) and sulfur coated urea (SCU) with various flooding periods (1, 7 and 60 days). Compared to the control soil, the AS-treated soil released more colloidal and dissolved Cu over the entire flooding period, while the SCU-treated soil had lower colloidal Cu after 7-day flooding but higher colloidal and dissolved Cu after 60-day flooding. Microscopic X-ray fluorescence (μ-XRF) analysis found a close relationship between Fe and Cu distribution on soil colloids after 60-day flooding, implying the formation of colloidal Fe/Cu sulphide coprecipitates. Cu K-edge X-ray absorption near-edge structure (XANES) spectroscopy directly revealed the transformation of outer-sphere complexed Cu(II) species to Cu(II) sulphide and reduced Cu2O in the colloids of S-treated soils after 60-day flooding. These results demonstrated the great influence of S fertilization on pore-water Cu mobility by forming Cu sulphide under flooding conditions, which facilitated our understanding and control of Cu loss in contaminated paddy soils under S fertilization. Copyright © 2015 Elsevier B.V. All rights reserved.

Dissipation and residues of emamectin benzoate study in paddy under field conditions.

PubMed

Li, Minghui; Chen, Weitao; Li, Mengyi; Han, Lijun

2011-12-01

The objective of this experiment was not only to provide a simple residue analytical method to evaluate the safe application rate of Emamectin Benzoate for paddy crops but also to give a suitable recommended dosage in paddy crops. Paddy samples were detected using HPLC-MS/MS. The half-lives of emamectin benzoate in paddy plants, water and soil were 2.04-8.66 days, 2.89-4.95 days and 3.65-5.78 days with a dissipation rate of 90% over 7 days after application, respectively. Low residues and short half-life suggested that Emamectin Benzoate could be safely used in paddy crops with the suitable dosage and application.

Comparative larvivorous performances of mosquitofish, Gambusia affinis, and juvenile Sacramento blackfish, Orthodon microlepidotus, in experimental paddies.

PubMed

Cech, J J; Linden, A L

1987-03-01

Mosquitofish, Sacramento blackfish, or combinations of both species were stocked in experimental paddies. Cultured Culex tarsalis larvae, stocked weekly into each paddy, and wild Anopheles freeborni larvae were counted by dipping. At the end of the 12 week experiment, paddies were drained and the remaining fish and visible invertebrates counted. Data show the highest number of mosquito larvae in the blackfish-stocked paddies. This low larvivorous ability of blackfish may result from their rapid growth to ca. 70 mm standard length and a consequent shift to a filtering mode of feeding. Although blackfish populations decreased from one-third to one-half of their stocked levels and mosquitofish populations increased to very high levels, mosquito control seemed to be a function of species rather than just the number of predatory fish. The lower number of larvae in the control paddies compared with the blackfish paddies might be attributable to predatory invertebrate communities.

Microscopic Structural Changes in Paddy Straw Pretreated with Trichoderma reesei MTCC 164 and Coriolus versicolor MTCC 138.

PubMed

Phutela, Urmila Gupta; Sahni, Nidhi

2013-06-01

The present study reports the pretreatment of paddy straw by Trichoderma reesei MTCC 164 and Coriolus versicolor MTCC 138 to observe the changes in chemical composition and its correlation with change of surface structure, morphology and porosity of paddy straw. Compared with untreated straw, cellulose decreased by 15.9 and 19.3 % in T. reesei MTCC 164 and C. versicolor MTCC 138 pretreated paddy straw respectively. Lignin content increased by 41.4 % in T. reesei pretreated paddy straw whereas decreased by 19.1 % in C. versicolor pretreated straw. The microscopic structural changes were examined by scanning electron microscopy under reasonable conditions. Results showed that digestibility of paddy straw are increased by treating paddy straw with both the cultures. Both surface area and pore size of treated straw were increased partially due to solubilization of silica components.

[Genetic diversity of psbA of cyanophage from paddy floodwater in northeast China].

PubMed

Jing, Ruiyong; Cao, Kun; Liu, Junjie; Liu, Judong; Jin, Jian; Liu, Xiaobing; Wang, Guanghua

2017-01-04

To provide scientific data for studying the ecology of cyanophage, we studied the genetic diversity of psbA of cyanophage from paddy floodwater in northeast China and its phylogenetic positions. Membrane separation and concentration of cyanophage, PCR-cloning-sequencing were applied to study the diversity of psbA of cyanophage from paddy floodwater in northeast China. In total 17 psbA sequences of cyanophage were obtained. Novel cyanophages were found by phylogenetic analysis. Compared to those of Japanese paddy floodwater, marine and lakes, psbA gene assemblage of paddy floodwater in northeast China was significantly different. This is the first report to study genetic diversity of cyanophage from paddy floodwater in northeast China with a molecular marker of psbA by PCR-cloning-sequencing. The novel psbA assembly of cyanophage was found in paddy floodwater in northeast China.

A Preliminary Study to Forecast Japanese Encephalitis Vector Abundance in Paddy Growing Area, with the Aid of Radar Satellite Images.

PubMed

Raju, K Hari Kishan; Sabesan, Shanmugavelu; Rajavel, Aladu Ramakrishnan; Subramanian, Swaminathan; Natarajan, Ramalingam; Thenmozhi, Velayutham; Tyagi, Brij Kishore; Jambulingam, Purushothaman

2016-02-01

Vector mosquitoes of Japanese encephalitis (JE) breed mostly in rice fields, and human cases occur scattered over extended rural rice-growing areas. From this, one may surmise an ecological connection with the irrigation facilities and paddy cultivation. Furthermore, it has been hypothesized that a particular stage of paddy growth is a premonitory sign that can lead to a markedly increased population of the vector mosquitoes. The present study aimed to forecast the vector abundance by monitoring the paddy growth using remote sensing and geographical information systems. The abundance of the JE vector Culex tritaeniorhynchus peaked when the paddy crop was at its heading stage and dipped when the crop reached the maturing stage. A significant positive correlation was observed between paddy growth and adult density (r = 0.73, p < 0.008). The sigma naught values (σ0) derived from satellite images of paddy fields ranged from -18.3 (during transplantation stage) to approximately -10 (during the noncultivation period). A significant positive correlation was observed between σ0 and paddy growth stages (r = 0.87, p < 0.05) and adult vector density (r = 0.74, p = 0.04). The σ0 value observed during the vegetative and flowering stages of paddy growth ranged from -17.6 to -17.16, at which period the vector density started building up. This could be the spectral signature that denotes the "risk," following which a high vector abundance is expected during heading stage of the paddy.

Mapping paddy rice planting area in cold temperate climate region through analysis of time series Landsat 8 (OLI), Landsat 7 (ETM+) and MODIS imagery

NASA Astrophysics Data System (ADS)

Qin, Yuanwei; Xiao, Xiangming; Dong, Jinwei; Zhou, Yuting; Zhu, Zhe; Zhang, Geli; Du, Guoming; Jin, Cui; Kou, Weili; Wang, Jie; Li, Xiangping

2015-07-01

Accurate and timely rice paddy field maps with a fine spatial resolution would greatly improve our understanding of the effects of paddy rice agriculture on greenhouse gases emissions, food and water security, and human health. Rice paddy field maps were developed using optical images with high temporal resolution and coarse spatial resolution (e.g., Moderate Resolution Imaging Spectroradiometer (MODIS)) or low temporal resolution and high spatial resolution (e.g., Landsat TM/ETM+). In the past, the accuracy and efficiency for rice paddy field mapping at fine spatial resolutions were limited by the poor data availability and image-based algorithms. In this paper, time series MODIS and Landsat ETM+/OLI images, and the pixel- and phenology-based algorithm are used to map paddy rice planting area. The unique physical features of rice paddy fields during the flooding/open-canopy period are captured with the dynamics of vegetation indices, which are then used to identify rice paddy fields. The algorithm is tested in the Sanjiang Plain (path/row 114/27) in China in 2013. The overall accuracy of the resulted map of paddy rice planting area generated by both Landsat ETM+ and OLI is 97.3%, when evaluated with areas of interest (AOIs) derived from geo-referenced field photos. The paddy rice planting area map also agrees reasonably well with the official statistics at the level of state farms (R2 = 0.94). These results demonstrate that the combination of fine spatial resolution images and the phenology-based algorithm can provide a simple, robust, and automated approach to map the distribution of paddy rice agriculture in a year.

Change of PAHs with evolution of paddy soils from prehistoric to present over the last six millennia in the Yangtze River Delta region, China.

PubMed

Zhang, Jin; Cornelia, Mueller-Niggemann; Wang, Minyan; Cao, Zhihong; Luo, Xiping; Wong, Minghung; Chen, Wei

2013-04-01

To evaluate the influence of hydroponics management on soil organic components with evolution of paddy soil over the last six millennia, PAHs, as a biomarker, as well as total organic carbon content were used to explore changes of paddy soil organic carbon in two entirely buried ancient paddy soil profiles. The results showed that hydroponics management can cause organic carbon deposition in rice paddy. The changing of total PAH concentrations was not always in accordance with the changing of total organic carbon contents in layers of the buried ancient paddy soils. The PAHs in 6280 BP prehistoric paddy soil layer was 3-ring>5-ring>4-ring>6-ring, while in layers of the present paddy soil and the prehistoric upland were 3-ring>4-ring>5-ring>6-ring. The contribution of phenanthrene to total PAHs in two profiles and the increasing ratio of phenanthrene to alkylated PAHs from parent material/6280 BP prehistoric upland to 6280 BP paddy suggested substantial increase of the anthropogenic influence of hydroponics management on rice paddy soil. And in view of the (14)C age and bioremains in the two profiles, it was only possible for PAHs to be derived from hydroponics management with evolution of the paddy soils form the Neolithic age. Cadalene could be used as an indicator for biological sources of PAHs released by rice plant residues, and benzo[g,h,i]fluoranthene and benzo[g,h,i]perylene for pyrogenic sources released by field vegetation fires. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Optimization on Paddy Crops in Central Java (with Solver, SVD on Least Square and ACO (Ant Colony Algorithm))

NASA Astrophysics Data System (ADS)

Parhusip, H. A.; Trihandaru, S.; Susanto, B.; Prasetyo, S. Y. J.; Agus, Y. H.; Simanjuntak, B. H.

2017-03-01

Several algorithms and objective functions on paddy crops have been studied to get optimal paddy crops in Central Java based on the data given from Surakarta and Boyolali. The algorithms are linear solver, least square and Ant Colony Algorithms (ACO) to develop optimization procedures on paddy crops modelled with Modified GSTAR (Generalized Space-Time Autoregressive) and nonlinear models where the nonlinear models are quadratic and power functions. The studied data contain paddy crops from Surakarta and Boyolali determining the best period of planting in the year 1992-2012 for Surakarta where 3 periods for planting are known and the optimal amount of paddy crops in Boyolali in the year 2008-2013. Having these analyses may guide the local agriculture government to give a decision on rice sustainability in its region. The best period for planting in Surakarta is observed, i.e. the best period is in September-December based on the data 1992-2012 by considering the planting area, the cropping area, and the paddy crops are the most important factors to be taken into account. As a result, we can refer the paddy crops in this best period (about 60.4 thousand tons per year) as the optimal results in 1992-2012 where the used objective function is quadratic. According to the research, the optimal paddy crops in Boyolali about 280 thousand tons per year where the studied factors are the amount of rainfalls, the harvested area and the paddy crops in 2008-2013. In this case, linear and power functions are studied to be the objective functions. Compared to all studied algorithms, the linear solver is still recommended to be an optimization tool for a local agriculture government to predict paddy crops in future.

Mapping paddy rice planting area in cold temperate climate region through analysis of time series Landsat 8 (OLI), Landsat 7 (ETM+) and MODIS imagery.

PubMed

Qin, Yuanwei; Xiao, Xiangming; Dong, Jinwei; Zhou, Yuting; Zhu, Zhe; Zhang, Geli; Du, Guoming; Jin, Cui; Kou, Weili; Wang, Jie; Li, Xiangping

2015-07-01

Accurate and timely rice paddy field maps with a fine spatial resolution would greatly improve our understanding of the effects of paddy rice agriculture on greenhouse gases emissions, food and water security, and human health. Rice paddy field maps were developed using optical images with high temporal resolution and coarse spatial resolution (e.g., Moderate Resolution Imaging Spectroradiometer (MODIS)) or low temporal resolution and high spatial resolution (e.g., Landsat TM/ETM+). In the past, the accuracy and efficiency for rice paddy field mapping at fine spatial resolutions were limited by the poor data availability and image-based algorithms. In this paper, time series MODIS and Landsat ETM+/OLI images, and the pixel- and phenology-based algorithm are used to map paddy rice planting area. The unique physical features of rice paddy fields during the flooding/open-canopy period are captured with the dynamics of vegetation indices, which are then used to identify rice paddy fields. The algorithm is tested in the Sanjiang Plain (path/row 114/27) in China in 2013. The overall accuracy of the resulted map of paddy rice planting area generated by both Landsat ETM+ and OLI is 97.3%, when evaluated with areas of interest (AOIs) derived from geo-referenced field photos. The paddy rice planting area map also agrees reasonably well with the official statistics at the level of state farms ( R 2 = 0.94). These results demonstrate that the combination of fine spatial resolution images and the phenology-based algorithm can provide a simple, robust, and automated approach to map the distribution of paddy rice agriculture in a year.

Hazardous gases and oxygen depletion in a wet paddy pile: an experimental study in a simulating underground rice mill pit, Thailand.

PubMed

Yenjai, Pornthip; Chaiear, Naesinee; Charerntanyarak, Lertchai; Boonmee, Mallika

2012-01-01

During the rice harvesting season in Thailand, large amounts of fresh paddy are sent to rice mills immediately after harvesting due to a lack of proper farm storage space. At certain levels of moisture content, rice grains may generate hazardous gases, which can replace oxygen (O(2)) in the confined spaces of underground rice mill pits. This phenomenon has been observed in a fatal accident in Thailand. Our study aimed to investigate the type of gases and their air concentrations emitted from the paddy piles at different levels of moisture content and duration of piling time. Four levels of moisture content in the paddy piles were investigated, including dry paddy group (< 14% wet basis (wb)), wet paddy groups (22-24, 25-27 and 28-30%wb). Our measurements were conducted in 16 experimental concrete pits 80 × 80 cm wide by 60 cm high. Gases emitted were measured with an infrared spectrophotometer and a multi-gas detector every 12 h for 5 days throughout the experiment. The results revealed high levels of carbon dioxide (CO(2)) (range 5,864-8,419 ppm) in all wet paddy groups, which gradually increased over time. The concentration of carbon monoxide (CO), methane (CH(4)), nitromethane (CH(3)NO(2)) and nitrous oxide (N(2)O) in all wet paddy groups increased with piling time and with moisture content, with ranges of 11-289; 2-8; 36-374; and 4-26 ppm, respectively. The highest levels of moisture content in the paddy piles were in the range 28-30%wb. Nitrogen dioxide (NO(2)) concentrations were low in all paddy groups. The percentage of O(2) in the wet paddy groups decreased with piling time and moisture content (from 18.7% to 4.1%). This study suggested that hazardous gases could be emitted in moist paddy piles, and their concentrations could increase with increasing moisture content and piling time period.

Mapping paddy rice planting area in northeastern Asia with Landsat 8 images, phenology-based algorithm and Google Earth Engine

PubMed Central

Dong, Jinwei; Xiao, Xiangming; Menarguez, Michael A.; Zhang, Geli; Qin, Yuanwei; Thau, David; Biradar, Chandrashekhar; Moore, Berrien

2016-01-01

Area and spatial distribution information of paddy rice are important for understanding of food security, water use, greenhouse gas emission, and disease transmission. Due to climatic warming and increasing food demand, paddy rice has been expanding rapidly in high latitude areas in the last decade, particularly in northeastern (NE) Asia. Current knowledge about paddy rice fields in these cold regions is limited. The phenology- and pixel-based paddy rice mapping (PPPM) algorithm, which identifies the flooding signals in the rice transplanting phase, has been effectively applied in tropical areas, but has not been tested at large scale of cold regions yet. Despite the effects from more snow/ice, paddy rice mapping in high latitude areas is assumed to be more encouraging due to less clouds, lower cropping intensity, and more observations from Landsat sidelaps. Moreover, the enhanced temporal and geographic coverage from Landsat 8 provides an opportunity to acquire phenology information and map paddy rice. This study evaluated the potential of Landsat 8 images on annual paddy rice mapping in NE Asia which was dominated by single cropping system, including Japan, North Korea, South Korea, and NE China. The cloud computing approach was used to process all the available Landsat 8 imagery in 2014 (143 path/rows, ~3290 scenes) with the Google Earth Engine (GEE) platform. The results indicated that the Landsat 8, GEE, and improved PPPM algorithm can effectively support the yearly mapping of paddy rice in NE Asia. The resultant paddy rice map has a high accuracy with the producer (user) accuracy of 73% (92%), based on the validation using very high resolution images and intensive field photos. Geographic characteristics of paddy rice distribution were analyzed from aspects of country, elevation, latitude, and climate. The resultant 30-m paddy rice map is expected to provide unprecedented details about the area, spatial distribution, and landscape pattern of paddy rice fields in NE Asia, which will contribute to food security assessment, water resource management, estimation of greenhouse gas emissions, and disease control. PMID:28025586

Mapping paddy rice planting area in northeastern Asia with Landsat 8 images, phenology-based algorithm and Google Earth Engine.

PubMed

Dong, Jinwei; Xiao, Xiangming; Menarguez, Michael A; Zhang, Geli; Qin, Yuanwei; Thau, David; Biradar, Chandrashekhar; Moore, Berrien

2016-11-01

Area and spatial distribution information of paddy rice are important for understanding of food security, water use, greenhouse gas emission, and disease transmission. Due to climatic warming and increasing food demand, paddy rice has been expanding rapidly in high latitude areas in the last decade, particularly in northeastern (NE) Asia. Current knowledge about paddy rice fields in these cold regions is limited. The phenology- and pixel-based paddy rice mapping (PPPM) algorithm, which identifies the flooding signals in the rice transplanting phase, has been effectively applied in tropical areas, but has not been tested at large scale of cold regions yet. Despite the effects from more snow/ice, paddy rice mapping in high latitude areas is assumed to be more encouraging due to less clouds, lower cropping intensity, and more observations from Landsat sidelaps. Moreover, the enhanced temporal and geographic coverage from Landsat 8 provides an opportunity to acquire phenology information and map paddy rice. This study evaluated the potential of Landsat 8 images on annual paddy rice mapping in NE Asia which was dominated by single cropping system, including Japan, North Korea, South Korea, and NE China. The cloud computing approach was used to process all the available Landsat 8 imagery in 2014 (143 path/rows, ~3290 scenes) with the Google Earth Engine (GEE) platform. The results indicated that the Landsat 8, GEE, and improved PPPM algorithm can effectively support the yearly mapping of paddy rice in NE Asia. The resultant paddy rice map has a high accuracy with the producer (user) accuracy of 73% (92%), based on the validation using very high resolution images and intensive field photos. Geographic characteristics of paddy rice distribution were analyzed from aspects of country, elevation, latitude, and climate. The resultant 30-m paddy rice map is expected to provide unprecedented details about the area, spatial distribution, and landscape pattern of paddy rice fields in NE Asia, which will contribute to food security assessment, water resource management, estimation of greenhouse gas emissions, and disease control.

Evaluating health of paddy rice field ecosystem with remote sensing and GIS in Lower Yangtze River Plain, China

NASA Astrophysics Data System (ADS)

Li, Jingjing; Qin, Zhihao; Li, Wenjuan; Lin, Lu

2008-10-01

A paddy rice ecosystem is a farming system composed of paddy, animals, microbes and other environmental factors in specific time and space, with particular temporal and spatial dynamics. Since paddy rice is a main grain crop to feed above half of population in China, the performance of paddy rice ecosystem is highly concerned to yield level of paddy and food supply safety in China. Therefore, monitoring the performance of paddy rice ecosystem is very important to obtain the required information for evaluation of ecosystem health. In the study we intend to develop an approach to monitor the ecosystem performance spatially and dynamically in a regional scale using MODIS remote sensing data and GIS spatial mapping. On the basis of key factors governing the paddy rice ecosystem, we accordingly develop the following three indicators for the evaluation: Crop growing index (CGI), environmental Index (EI), and pests-diseases index (PDI). Then, we integrated the three indicators into a model with different weight coefficients to calculate Comprehensive ecosystem health index (CEHI) to evaluate the performance and functioning of paddy rice ecosystem in a regional scale. CGI indicates the health status of paddy rice calculated from the normalizing enhanced vegetation Index (EVI) retrieved from MODIS data. EI is estimated from temperature Index (TI) and precipitation Index (PI) indicating heat and water stress on the rice field. PDI reflects the damage brought by pests and diseases, which can be estimated using the information obtained from governmental websites. Applying the approach to Lower Yangtze River Plain, we monitor and evaluate the performance of paddy rice ecosystem in various stages of rice growing period in 2006. The results indicated that the performance of the ecosystem was generally very encouraging. During booting stage and heading and blooming stage, the health level was the highest in Anhui province, which is the main paddy rice producer in the region. During stage of yellow ripeness, Jiangsu province had the lowest level of performance. Yield level of paddy rice in 2006 confirms that the applicability of the proposed approach for a rapid evaluation and monitoring of agricultural ecosystem performance in Lower Yangtze River Plain. As a result, the new approach could supply scientific basis for relevant departments taking policies and measures to make sure stable development of paddy yield.

Moisture content measurement in paddy

NASA Astrophysics Data System (ADS)

Klomklao, P.; Kuntinugunetanon, S.; Wongkokua, W.

2017-09-01

Moisture content is an important quantity for agriculture product, especially in paddy. In principle, the moisture content can be measured by a gravimetric method which is a direct method. However, the gravimetric method is time-consuming. There are indirect methods such as resistance and capacitance methods. In this work, we developed an indirect method based on a 555 integrated circuit timer. The moisture content sensor was capacitive parallel plates using the dielectric constant property of the moisture. The instrument generated the output frequency that depended on the capacitance of the sensor. We fitted a linear relation between periods and moisture contents. The measurement results have a standard uncertainty of 1.23 % of the moisture content in the range of 14 % to 20 %.

Detection of pesticides residues in water samples from organic and conventional paddy fields of Ledang, Johor, Malaysia

NASA Astrophysics Data System (ADS)

Abdullah, Md Pauzi; Othman, Mohamed Rozali; Ishak, Anizan; Nabhan, Khitam Jaber

2016-11-01

Pesticides have been used extensively by the farmers in Malaysia during the last few decades. Sixteen water samples, collected from paddy fields both organic and conventional, from Ledang, Johor, were analyzed to determine the occurrence and distribution of organochlorine (OCPs) and organophosphorus (OPPs) pesticide residues. GC-ECD instrument was used to identify and determine the concentrations of these pesticide residues. Pesticide residues were detected in conventional fields in the range about 0.036-0.508 µg/L higher than detected in organic fields about 0.015-0.428 µg/L. However the level of concentration of pesticide residues in water sample from both paddy fields are in the exceed limit for human consumption, according to European Economic Commission (EEC) (Directive 98/83/EC) at 0.1 µg/L for any pesticide or 0.5 µg/L for total pesticides. The results that the organic plot is still contaminated with pesticides although pesticides were not use at all in plot possibly from historical used as well as from airborne contamination.

Mapping Early, Middle and Late Rice Extent Using Sentinel-1A and Landsat-8 Data in the Poyang Lake Plain, China

PubMed Central

Wu, Mingquan; Wang, Li

2018-01-01

Areas and spatial distribution information of paddy rice are important for managing food security, water use, and climate change. However, there are many difficulties in mapping paddy rice, especially mapping multi-season paddy rice in rainy regions, including differences in phenology, the influence of weather, and farmland fragmentation. To resolve these problems, a novel multi-season paddy rice mapping approach based on Sentinel-1A and Landsat-8 data is proposed. First, Sentinel-1A data were enhanced based on the fact that the backscattering coefficient of paddy rice varies according to its growth stage. Second, cropland information was enhanced based on the fact that the NDVI of cropland in winter is lower than that in the growing season. Then, paddy rice and cropland areas were extracted using a K-Means unsupervised classifier with enhanced images. Third, to further improve the paddy rice classification accuracy, cropland information was utilized to optimize distribution of paddy rice by the fact that paddy rice must be planted in cropland. Classification accuracy was validated based on ground-data from 25 field survey quadrats measuring 600 m × 600 m. The results show that: multi-season paddy rice planting areas effectively was extracted by the method and adjusted early rice area of 1630.84 km2, adjusted middle rice area of 556.21 km2, and adjusted late rice area of 3138.37 km2. The overall accuracy was 98.10%, with a kappa coefficient of 0.94. PMID:29324647

Populations of Rice Grain Bug, Paraeuscosmetus pallicomis, (Hemiptera: Lygaeidae) in Weed-free Paddy Field, Weedy Paddy Field and Paddy Dykes.

PubMed

Abdullah, Tamrin; Nasruddin, Andi; Agus, Nurariaty

2017-07-01

Research on the populations of rice grain bug Paraeuscosmetus pallicomis Dallas (Hemiptera: Lygaeidae) in paddy field ecosystems was performed with the aim to determine the populations of rice grain bug in weed-free paddy field, weedy paddy field, and paddy dykes. Experiment was carried out in the village of Paccellekang in the district of Patallasang of Gowa Regency in South Sulawesi, Indonesia. Observations were performed during the milky grain stage (85 days after planting), the mature grain stage (105 days after planting), and one day after harvest (115 days after transplanting). Results showed that 85 days after the transplanting, the populations of rice grain bug was significantly higher in the weedy paddy field compared to weed-free field and paddy dykes with total numbers of 1.75, 3.53, and 0.31 insects per 2 hills, respectively. Similarly, 105 days after the transplanting, 2.53, 5.53, and 0.11 insects per hill, respectively. However, one day after the harvest (115 days after transplanting) the number of insects in weed-free field decreased, while in the dykes increased, and the weedy plot still had the highest number of insects per 2 hills. Our results suggested that weeds played an important role in regulating the bug population by providing alternative shelter and foods for the insect.

Populations of Rice Grain Bug, Paraeuscosmetus pallicomis, (Hemiptera: Lygaeidae) in Weed-free Paddy Field, Weedy Paddy Field and Paddy Dykes

PubMed Central

Abdullah, Tamrin; Nasruddin, Andi; Agus, Nurariaty

2017-01-01

Research on the populations of rice grain bug Paraeuscosmetus pallicomis Dallas (Hemiptera: Lygaeidae) in paddy field ecosystems was performed with the aim to determine the populations of rice grain bug in weed-free paddy field, weedy paddy field, and paddy dykes. Experiment was carried out in the village of Paccellekang in the district of Patallasang of Gowa Regency in South Sulawesi, Indonesia. Observations were performed during the milky grain stage (85 days after planting), the mature grain stage (105 days after planting), and one day after harvest (115 days after transplanting). Results showed that 85 days after the transplanting, the populations of rice grain bug was significantly higher in the weedy paddy field compared to weed-free field and paddy dykes with total numbers of 1.75, 3.53, and 0.31 insects per 2 hills, respectively. Similarly, 105 days after the transplanting, 2.53, 5.53, and 0.11 insects per hill, respectively. However, one day after the harvest (115 days after transplanting) the number of insects in weed-free field decreased, while in the dykes increased, and the weedy plot still had the highest number of insects per 2 hills. Our results suggested that weeds played an important role in regulating the bug population by providing alternative shelter and foods for the insect. PMID:28890757

[Effects of mechanical transplanting of rice with controlled release bulk blending fertilizer on rice yield and soil fertility].

PubMed

Zhang, Xuan; Ding, Jun-Shan; Liu, Yan-Ling; Gu, Yan; Han, Ke-Feng; Wu, Liang-Huan

2014-03-01

Abstract: A 2-year field experiment with a yellow-clay paddy soil in Zhejiang Province was conducted to study the effects of different planting measures combined with different fertilization practices on rice yield, soil nutrients, microbial biomass C and N and activities of urease, phosphatase, sucrase and hydrogen peroxidase at the maturity stage. Results showed that mechanical transplanting of rice with controlled release bulk blending (BB) fertilizer (BBMT) could achieve a significantly higher mean yield than traditional manual transplanting with traditional fertilizer (TFTM) and direct seeding with controlled release BB fertilizer (BBDS) by 16.3% and 27.0%, respectively. The yield by BBMT was similar to that by traditional manual transplanting with controlled release BB fertilizer (BBTM). Compared with TFTM, BBMT increased the contents of soil total-N, available N, available P and microbial biomass C, and the activities of urease, sucrase and hydrogen peroxidase by 21.5%, 13.6%, 41.2%, 27.1%, 50.0%, 22.5% and 46.2%, respectively. Therefore, BBMT, a simple high-efficiency rice cultivation method with use of a light-weighted mechanical transplanter, should be widely promoted and adopted.

Dissolved carbon and nitrogen dynamics in paddy fields under different water management practices and implications on green-house gas emissions

NASA Astrophysics Data System (ADS)

Miniotti, Eleonora; Said-Pullicino, Daniel; Bertora, Chiara; Pelissetti, Simone; Sacco, Dario; Grignani, Carlo; Lerda, Cristina; Romani, Marco; Celi, Luisella

2013-04-01

The alternation of oxidizing and reducing conditions in paddy soils results in considerable complexity in the biogeochemical cycling of elements and their interactions, influencing important soil processes. Water management practices may play an important role in controlling the loss of nutrients from rice paddies to surface and subsurface waters, as well as soil organic matter (SOM) stabilization and the emission of green-house gases (GHG) such as methane and nitrous oxide. The aim of this study was therefore to evaluate the interaction between changes in soil redox conditions and element cycling in temperate paddy soils as a function of different water management practices. The research was carried out within an experimental platform (1.2 ha) located at the Rice Research Center of Ente Nazionale Risi (Castello d'Agogna, PV, NW Italy) where three water management practices are being compared with two plots for each treatment. These included (i) rice cultivation under traditional submerged conditions (FLD); (ii) seeding under dry soil conditions and flooding delayed by about 40 days (DRY); (iii) seeding under dry soil conditions and rotational irrigation (IRR). Surface and subsurface (25, 50 and 75 cm) water samples were collected at regular intervals over the cropping season from V-notch weirs and porous ceramic suction cups installed in each plot, and subsequently analyzed for DOC, SUVA, Fe(II), ammonium and nitrate-N. Moreover, methane and nitrous oxide fluxes were measured in situ by the closed-chamber technique. DOC concentrations in soil solutions were generally higher in FLD and DRY treatments with respect to IRR throughout the cropping season. Higher DOC contents after field flooding in FLD and DRY treatments also corresponded with greater concentrations of reduced Fe, higher SUVA values, lower Eh values and higher pH values, suggesting that desorption of more aromatic, mineral-associated SOM could be responsible for the observed increase in DOC. These trends were not observed in the IRR treatment. The differences in DOC contents and in Eh trend between treatments could possibly explain the increasing trend in cumulative methane emissions in the order IRR<

Spatiotemporal patterns of paddy rice croplands in China and India from 2000 to 2015.

PubMed

Zhang, Geli; Xiao, Xiangming; Biradar, Chandrashekhar M; Dong, Jinwei; Qin, Yuanwei; Menarguez, Michael A; Zhou, Yuting; Zhang, Yao; Jin, Cui; Wang, Jie; Doughty, Russell B; Ding, Mingjun; Moore, Berrien

2017-02-01

Due to rapid population growth and urbanization, paddy rice agriculture is experiencing substantial changes in the spatiotemporal pattern of planting areas in the two most populous countries-China and India-where food security is always the primary concern. However, there is no spatially explicit and continuous rice-planting information in either country. This knowledge gap clearly hinders our ability to understand the effects of spatial paddy rice area dynamics on the environment, such as food and water security, climate change, and zoonotic infectious disease transmission. To resolve this problem, we first generated annual maps of paddy rice planting areas for both countries from 2000 to 2015, which are derived from time series Moderate Resolution Imaging Spectroradiometer (MODIS) data and the phenology- and pixel-based rice mapping platform (RICE-MODIS), and analyzed the spatiotemporal pattern of paddy rice dynamics in the two countries. We found that China experienced a general decrease in paddy rice planting area with a rate of 0.72 million (m) ha/yr from 2000 to 2015, while a significant increase at a rate of 0.27mha/yr for the same time period happened in India. The spatial pattern of paddy rice agriculture in China shifted northeastward significantly, due to simultaneous expansions in paddy rice planting areas in northeastern China and contractions in southern China. India showed an expansion of paddy rice areas across the entire country, particularly in the northwestern region of the Indo-Gangetic Plain located in north India and the central and south plateau of India. In general, there has been a northwesterly shift in the spatial pattern of paddy rice agriculture in India. These changes in the spatiotemporal patterns of paddy rice planting area have raised new concerns on how the shift may affect national food security and environmental issues relevant to water, climate, and biodiversity. Copyright © 2016 Elsevier B.V. All rights reserved.

Performance Study of Fluidized Bed Dryer with Immersed Heater for Paddy Drying

NASA Astrophysics Data System (ADS)

Suherman, S.; Azaria, N. F.; Karami, S.

2018-03-01

This paper investigated the performance of fluidized bed dryer with immersed heater for paddy drying. The influence of drying temperature and the temperature of immersed heater on drying curve, thermal efficiency, and quality of paddy was investigated. The fixed operating conditions are drying time of 60 minutes, paddy weight of 200 grams and the air velocity of 0.4 m/s. The variables are drying temperature and the temperature immersed heater namely 50, 60, 70, 80, 90 (°C). The results show addition immersed heater will increase drying rates. No constant drying rate was found. Increasing the temperature will decrease the utilized energy. The thermal efficiency decreases with increasing temperature. The increasing temperature and use immersed heater will decrease the residual moisture content, increase damaged and yellow paddy grain, and increase red paddy grain.

Carbon and 14C distribution in tropical and subtropical agricultural soils

NASA Astrophysics Data System (ADS)

Prastowo, Erwin; Grootes, Pieter; Nadeau, Marie

2016-04-01

Paddy soil management affects, through the alternating anoxic and oxic conditions it creates, the transport and stabilisation of soil organic matter (SOM). Irrigation water may percolate more organic materials - dissolved (DOM) and colloidal - into the subsoil during anoxic conditions. Yet a developed ploughpan tends to prevent C from going deeper in the subsoil and partly decouple C distribution in top and sub soil. We investigate the influence of different soil type and environment. We observed the C and 14C distribution in paddy and non-paddy soil profiles in three different soil types from four different climatic regions of tropical Indonesia, and subtropical China. Locations were Sukabumi (Andosol, ca. 850 m a.s.l), Bogor (clayey Alisol, ca. 240 m a.s.l), and Ngawi (Vertisol, ca. 70 m a.s.l) in Jawa, Indonesia, and Cixi (Alisol(sandy), ca. 4 - 6 m a.s.l) in Zhejiang Province, China. We compared rice paddies with selected neighbouring non-paddy fields and employed AMS 14C as a tool to study C dynamics from bulk, alkali soluble-humic, and insoluble humin samples, and macrofossils (plant remains, charcoal). Our data suggest that vegetation type determines the quantity and quality of biomass introduced as litter and root material in top and subsoil, and thus contributes to the soil C content and profile, which fits the 14C signal distribution, as well as 13C in Ngawi with C4 sugar cane as upland crop. 14C concentrations for the mobile humic acid fraction were generally higher than for bulk samples from the same depth, except when recent plant and root debris led to high 14C levels in near-surface samples. The difference in sampling, - averaged layer for bulk sample and 1-cm layer thickness for point sample - shows gradients in C and 14C across the layers, which could be a reason for discrepancies between the two. High 14C concentrations - in Andosol Sukabumi up to 111 pMC - exceed the atmospheric 14CO2concentration in the sampling year in 2012 (˜ 103 pMC) and reflect stored organic material from earlier years with a higher atmospheric bomb 14C content. Direct inputs of plant material into the subsoil is indicated by young organic remains with more than 103 pMC below 0.8 m depth. In combination with 13C observation, it is quite obvious that introduction of young C took place in both paddy and non-paddy.

Paddy straw as a substrate for the cultivation of Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W.Curt.:Fr.) P. Karst. in India.

PubMed

Veena, S S; Pandey, Meera

2011-01-01

Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum, is generally cultivated on hardwood logs or sawdust/woodchips based formulations. More than 100 million tonnes of paddy straw is being produced in India per year, and almost 50% of the straw is potentially available for growing mushrooms. In the present study an attempt was made to use paddy straw as a substrate to cultivate G. lucidim. Different proportions of paddy straw were mixed with 0, 22.5%, 45%, and 67.5% sawdust and 10% rice bran. Spawn run period, fruiting initiation period, yield, moisture content, dry recovery, and fruiting body characteristics were recorded and compared. Fructification was observed with all the substrate formulations and they did not show any significant difference in yield. The highest biological efficiency (BE) (29.9%) was observed with the combination sawdust:paddy straw:rice bran 22.5:67.5:10, followed by saw dust:paddy straw:rice bran 45:45:10 with BE 27.3%. The current study demonstrated for the first time that the cultivation of G. lucidum is possible with paddy straw as the base substrate and indicated the enormous potential of paddy straw for the cultivation of G. lucidum.

Mapping paddy rice planting area in wheat-rice double-cropped areas through integration of Landsat-8 OLI, MODIS, and PALSAR images.

PubMed

Wang, Jie; Xiao, Xiangming; Qin, Yuanwei; Dong, Jinwei; Zhang, Geli; Kou, Weili; Jin, Cui; Zhou, Yuting; Zhang, Yao

2015-05-12

As farmland systems vary over space and time (season and year), accurate and updated maps of paddy rice are needed for studies of food security and environmental problems. We selected a wheat-rice double-cropped area from fragmented landscapes along the rural-urban complex (Jiangsu Province, China) and explored the potential utility of integrating time series optical images (Landsat-8, MODIS) and radar images (PALSAR) in mapping paddy rice planting areas. We first identified several main types of non-cropland land cover and then identified paddy rice fields by selecting pixels that were inundated only during paddy rice flooding periods. These key temporal windows were determined based on MODIS Land Surface Temperature and vegetation indices. The resultant paddy rice map was evaluated using regions of interest (ROIs) drawn from multiple high-resolution images, Google Earth, and in-situ cropland photos. The estimated overall accuracy and Kappa coefficient were 89.8% and 0.79, respectively. In comparison with the National Land Cover Data (China) from 2010, the resultant map better detected changes in the paddy rice fields and revealed more details about their distribution. These results demonstrate the efficacy of using images from multiple sources to generate paddy rice maps for two-crop rotation systems.

Mercury methylation in rice paddies and its possible controlling factors in the Hg mining area, Guizhou province, Southwest China.

PubMed

Zhao, Lei; Qiu, Guangle; Anderson, Christopher W N; Meng, Bo; Wang, Dingyong; Shang, Lihai; Yan, Haiyu; Feng, Xinbin

2016-08-01

Understanding mercury (Hg) methylation/demethylation processes and the factors controlling methylmercury (MeHg) production within the rice paddy ecosystem of Hg mining areas is critical to assess the risk of MeHg contamination in rice grain. Two typical Hg-contaminated mining sites, a current-day artisanal site (Gouxi) and an abandoned site (Wukeng), were chosen in this study. We qualified the in situ specific methylation/demethylation rate constants in rice paddy soil during a complete rice-growing season. Our results demonstrate that MeHg levels in rice paddy soil were a function of both methylation and demethylation processes and the net methylation potential in the rice paddy soil reflected the measured MeHg production at any time point. Sulfate stimulating the activity of sulfate-reducing bacteria was a potentially important metabolic pathway for Hg methylation in rice paddies. We suggest that bioavailable Hg derived from new atmospheric deposition appears to be the primary factor regulating net MeHg production in rice paddies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fipronil application on rice paddy fields reduces densities of common skimmer and scarlet skimmer

PubMed Central

Kasai, Atsushi; Hayashi, Takehiko I.; Ohnishi, Hitoshi; Suzuki, Kazutaka; Hayasaka, Daisuke; Goka, Koichi

2016-01-01

Several reports suggested that rice seedling nursery-box application of some systemic insecticides (neonicotinoids and fipronil) is the cause of the decline in dragonfly species noted since the 1990s in Japan. We conducted paddy mesocosm experiments to investigate the effect of the systemic insecticides clothianidin, fipronil and chlorantraniliprole on rice paddy field biological communities. Concentrations of all insecticides in the paddy water were reduced to the limit of detection within 3 months after application. However, residuals of these insecticides in the paddy soil were detected throughout the experimental period. Plankton species were affected by clothianidin and chlorantraniliprole right after the applications, but they recovered after the concentrations decreased. On the other hand, the effects of fipronil treatment, especially on Odonata, were larger than those of any other treatment. The number of adult dragonflies completing eclosion was severely decreased in the fipronil treatment. These results suggest that the accumulation of these insecticides in paddy soil reduces biodiversity by eliminating dragonfly nymphs, which occupy a high trophic level in paddy fields. PMID:26979488

Energy and environmental impact analysis of rice cultivation and straw management in northern Thailand.

PubMed

Yodkhum, Sanwasan; Sampattagul, Sate; Gheewala, Shabbir H

2018-04-17

Rice cultivation and energy use for rice production can produce the environmental impacts, especially related to greenhouse gas (GHG) emissions. Also, rice straw open burning by farmers generally practiced after harvesting stage in Thailand for removing the residues in the rice field is associated with emissions of air pollutants, especially particulate matter formation that affects human health and global climate. This study assessed the environmental burdens, consisting of GHG emissions, energy use, and particulate matter formation (PM10), from rice cultivation in Thailand by life cycle assessment (LCA) and compared the environmental burdens of rice straw management scenarios: open burning, incorporation into soil, and direct combustion for electricity generation. The data were collected from the rice production cooperative in Chiang Mai province, northern Thailand, via onsite records and face-to-face questionnaires in 2016. The environmental impacts were evaluated from cradle-to-farm gate. The results showed that the total GHG emissions were 0.64 kg CO 2 -eq per kilogram of paddy rice, the total energy use was 1.80 MJ per kilogram of paddy rice and the PM10 emissions were 0.42 g PM10-eq per kilogram of paddy rice. The results of rice straw management scenarios showed that rice straw open burning had the highest GHG and PM10 emissions. However, rice straw utilization by incorporation into soil and direct combustion for electricity generation could reduce these impacts substantially.

Northward expansion of paddy rice in northeastern Asia during 2000-2014.

PubMed

Dong, J; Xiao, X; Zhang, G; Menarguez, M A; Choi, C Y; Qin, Y; Luo, P; Zhang, Y; Moore, B

2016-04-28

Paddy rice in monsoon Asia plays an important role in global food security and climate change. Here we documented annual dynamics of paddy rice areas in the northern frontier of Asia, including Northeastern (NE) China, North Korea, South Korea, and Japan, from 2000-2014 through analysis of satellite images. The paddy rice area has increased by 120% (2.5 to 5.5 million ha) in NE China, in comparison to a decrease in South Korea and Japan, and the paddy rice centroid shifted northward from 41.16 °N to 43.70 °N (~310 km) in this period. Market, technology, policy, and climate together drove the rice expansion in NE China. The increased use of greenhouse nurseries, improved rice cultivars, agricultural subsidy policy, and a rising rice price generally promoted northward paddy rice expansion. The potential effects of large rice expansion on climate change and ecological services should be paid more attention in the future.

Methane and Nitrous Oxide Emissions Reduced Following Conversion of Rice Paddies to Inland Crab-Fish Aquaculture in Southeast China.

PubMed

Liu, Shuwei; Hu, Zhiqiang; Wu, Shuang; Li, Shuqing; Li, Zhaofu; Zou, Jianwen

2016-01-19

Aquaculture is an important source of atmospheric methane (CH4) and nitrous oxide (N2O), while few direct flux measurements are available for their regional and global source strength estimates. A parallel field experiment was performed to measure annual CH4 and N2O fluxes from rice paddies and rice paddy-converted inland crab-fish aquaculture wetlands in southeast China. Besides N2O fluxes dependent on water/sediment mineral N and CH4 fluxes related to water chemical oxygen demand, both CH4 and N2O fluxes from aquaculture were related to water/sediment temperature, sediment dissolved organic carbon, and water dissolved oxygen concentration. Annual CH4 and N2O fluxes from inland aquaculture averaged 0.37 mg m(-2) h(-1) and 48.1 μg m(-2) h(-1), yielding 32.57 kg ha(-1) and 2.69 kg N2O-N ha(-1), respectively. The conversion of rice paddies to aquaculture significantly reduced CH4 and N2O emissions by 48% and 56%, respectively. The emission factor for N2O was estimated to be 0.66% of total N input in the feed or 1.64 g N2O-N kg(-1) aquaculture production in aquaculture. The conversion of rice paddies to inland aquaculture would benefit for reconciling greenhouse gas mitigation and agricultural income increase as far as global warming potentials and net ecosystem economic profits are of concomitant concern. Some agricultural practices such as better aeration and feeding, and fallow season dredging would help to lower CH4 and N2O emissions from inland aquaculture. More field measurements from inland aquaculture are highly needed to gain an insight into national and global accounting of CH4 and N2O emissions.

Preliminary Study on the Radar Vegetation Index (RVI) Application to Actual Paddy Fields by ALOS/PALSAR Full-polarimetry SAR Data

NASA Astrophysics Data System (ADS)

Yamada, Y.

2015-04-01

Kim and van Zyl (2001) proposed a kind of radar vegetation index (RVI). RVI = 4*min(λ1, λ2, λ3) / (λ1 + λ2 + λ3) They modified the equation as follows. (2009) RVI = 8 * σ0hv / (σ0hh + σ0vv +σ0hv ) by L-band full-polarimetric SAR data. They applied it into rice crop and soybean. (Y.Kim, T.Jackson et al., 2012) They compared RVI for L-, C- and X-bands to crop growth data, LAI and NDVI. They found L-band RVI was well correlated with Vegetation Water Content, LAI and NDVI. But the field data were collected by the multifrequency polarimetric scatterometer. The platform height was 4.16 meters from the ground. The author tried to apply the method to actual paddy fields near Tsukuba science city in Japan using ALOS/PALSAR, full-polarimetry L-band SAR data. The staple crop in Eastern Asia is rice and paddy fields are dominant land use. A rice-planting machine comes into wide use in this areas. The young rice plants were bedded regularly ridged line in the paddy fields by the machine. The space between two ridges of rice plants is about 30 cm and the wave length of PALSAR sensor is about 23 cm. Hence the Bragg scattering will appear depending upon the direction of the ridges of paddy fields. Once the Bragg scattering occurs, the backscattering values from the pixels should be very high comparing the surrounding region. Therefore the radar vegetation index (RVI) would be saturated. The RVI did not follow the increasing of vegetation anymore. Japan has launched ALOS-2 satellite and it has PALSAR-2, L-band SAR. Therefore RVI application product by PALSAR-2 will be watched with deep interest.

[Research on characteristics of soil clay mineral evolution in paddy field and dry land by XRD spectrum].

PubMed

Zhang, Zhi-dan; Li, Qiao; Luo, Xiang-li; Jiang, Hai-chao; Zheng, Qing-fu; Zhao, Lan-po; Wang, Ji-hong

2014-08-01

The present paper took the typical saline-alkali soil in Jilin province as study object, and determinated the soil clay mineral composition characteristics of soil in paddy field and dry land. Then XRD spectrum was used to analyze the evolutionary mechanism of clay mineral in the two kinds of soil. The results showed that the physical and chemical properties of soil in paddy field were better than those in dry land, and paddy field would promote the weathering of mineral particles in saline-alkali soil and enhance the silt content. Paddy field soil showed a strong potassium-removal process, with a higher degree of clay mineral hydration and lower degree of illite crystallinity. Analysis of XRD spectrum showed that the clay mineral composition was similar in two kinds of soil, while the intensity and position of diffraction peak showed difference. The evolution process of clay mineral in dry land was S/I mixture-->vermiculite, while in paddy field it was S/I mixture-->vermiculite-->kaolinite. One kind of hydroxylated 'chlorite' mineral would appear in saline-alkali soil in long-term cultivated paddy field. Taking into account that the physical and chemical properties of soil in paddy field were better then those in dry land, we could know that paddy field could help much improve soil structure, cultivate high-fertility soil and improve saline-alkali soil. This paper used XRD spectrum to determine the characteristics of clay minerals comprehensively, and analyzed two'kinds of land use comparatively, and was a new perspective of soil minerals study.

The Spatiotemporal pattern and driving forces of the paddy in the Northeastern China

NASA Astrophysics Data System (ADS)

Du, G.; Li, Q.; Chun, X.

2017-12-01

The cropland is the production place that protects the regional food security, and the paddy is the main part of the cropland. Since the 21st century, the China's socio-economy has been grown, the structure of the cropland has significantly changed. The Northeast region has gradually become one of the major commodity grain production bases. Meanwhile, the paddy also has gradually increased year by year. Therefore, it is necessary that analyze the tempo-spatial characteristics and the influencing factors of the northeast in China, and the results provide the basis that reveals the change of cropland structure and its causes.In this study, we use the spatial models of GIS and mathematical statistics methods to analyze the tempo-spatial characteristics and the influencing facts of the paddy in the Northeastern China with the spatial data from 2000 to 2015. In order to fully characterize the spatiotemporal characteristics of the paddy, we choose single land use type dynamic degree and land use extension index to quantitatively describe the change degree and the speed of the regional paddy, and the characteristics are visualized with "3S" means. Meanwhile, the relative change rate and the center of gravity model are chosen to explore the region differences and the distribution of the distribution center of paddy field change in Northeast China. In addition, in order to further reveal the cause of the paddy change, we use the OLS, SAM or SEM models to analyze the main influencing factors of spatiotemporal variation of the paddy field.

Radiocesium discharge from paddy fields with different initial scrapings for decontamination after the Fukushima Dai-ichi Nuclear Power Plant accident.

PubMed

Wakahara, Taeko; Onda, Yuich; Kato, Hiroaki; Sakaguchi, Aya; Yoshimura, Kazuya

2014-11-01

To explore the behavior of radionuclides released after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011, and the distribution of radiocesium in paddy fields, we monitored radiocesium (Cs) and suspended sediment (SS) discharge from paddy fields. We proposed a rating scale for measuring the effectiveness of surface soil removal. Our experimental plots in paddy fields were located ∼40 km from the FDNPP. Two plots were established: one in a paddy field where surface soil was not removed (the "normally cultivated paddy field") and the second in a paddy field where the top 5-10 cm of soil was removed before cultivation (the "surface-removed paddy field"). The amounts of Cs and SS discharge from the paddy fields were continuously measured from June to August 2011. The Cs soil inventory measured 3 months after the FDNPP accident was approximately 200 kBq m(-2). However, after removing the surface soil, the concentration of Cs-137 decreased to 5 kBq m(-2). SS discharged from the normally cultivated and surface-removed paddy fields after puddling (mixing of soil and water before planting rice) was 11.0 kg and 3.1 kg, respectively, and Cs-137 discharge was 630,000 Bq (1240 Bq m(-2)) and 24,800 Bq (47.8 Bq m(-2)), respectively. The total amount of SS discharge after irrigation (natural rainfall-runoff) was 5.5 kg for the normally cultivated field and 70 kg for the surface-removed field, and the total amounts of Cs-137 discharge were 51,900 Bq (102 Bq m(-2)) and 165,000 Bq (317 Bq m(-2)), respectively. During the irrigation period, discharge from the surface-removed plot showed a twofold greater inflow than that from the normally cultivated plot. Thus, Cs inflow may originate from the upper canal. The topsoil removal process eliminated at least approximately 95% of the Cs-137, but upstream water contaminated with Cs-137 flowed into the paddy field. Therefore, to accurately determine the Cs discharge, it is important to examine Cs inflow from the upper channel. Furthermore, puddling and irrigation processes inhibit the discharge of radiocesium downstream. This indicates that water control in paddy fields is an important process in the prevention of river pollution and radionuclide transfer.

A quadratic regression modelling on paddy production in the area of Perlis

NASA Astrophysics Data System (ADS)

Goh, Aizat Hanis Annas; Ali, Zalila; Nor, Norlida Mohd; Baharum, Adam; Ahmad, Wan Muhamad Amir W.

2017-08-01

Polynomial regression models are useful in situations in which the relationship between a response variable and predictor variables is curvilinear. Polynomial regression fits the nonlinear relationship into a least squares linear regression model by decomposing the predictor variables into a kth order polynomial. The polynomial order determines the number of inflexions on the curvilinear fitted line. A second order polynomial forms a quadratic expression (parabolic curve) with either a single maximum or minimum, a third order polynomial forms a cubic expression with both a relative maximum and a minimum. This study used paddy data in the area of Perlis to model paddy production based on paddy cultivation characteristics and environmental characteristics. The results indicated that a quadratic regression model best fits the data and paddy production is affected by urea fertilizer application and the interaction between amount of average rainfall and percentage of area defected by pest and disease. Urea fertilizer application has a quadratic effect in the model which indicated that if the number of days of urea fertilizer application increased, paddy production is expected to decrease until it achieved a minimum value and paddy production is expected to increase at higher number of days of urea application. The decrease in paddy production with an increased in rainfall is greater, the higher the percentage of area defected by pest and disease.

Organic fertilizer application increases the soil respiration and net ecosystem carbon dioxide absorption of paddy fields under water-saving irrigation.

PubMed

Yang, Shihong; Xiao, Ya Nan; Xu, Junzeng

2018-04-01

Quantifying carbon sequestration in paddy soil is necessary to understand the effect of agricultural practices on carbon cycles. The objective of this study was to assess the effect of organic fertilizer addition (MF) on the soil respiration and net ecosystem carbon dioxide (CO 2 ) absorption of paddy fields under water-saving irrigation (CI) in the Taihu Lake Region of China during the 2014 and 2015 rice-growing seasons. Compared with the traditional fertilizer and water management (FC), the joint regulation of CI and MF (CM) significantly increased the rice yields and irrigation water use efficiencies of paddy fields by 4.02~5.08 and 83.54~109.97% (p < 0.05). The effects of organic fertilizer addition on soil respiration and net ecosystem CO 2 absorption rates showed inter-annual differences. CM paddy fields showed a higher soil respiration and net CO 2 absorption rates during some periods of the rice growth stage in the first year and during most periods of the rice growth stage in the second year. These fields also had significantly higher total CO 2 emission through soil respiration (total R soil ) and total net CO 2 absorption compared with FC paddy fields (p < 0.05). The total R soil and net ecosystem CO 2 absorption of CM paddy fields were 67.39~91.55 and 129.41~113.75 mol m -2 , which were 27.66~135.52 and 12.96~31.66% higher than those of FC paddy fields. The interaction between water and fertilizer management had significant effects on total net ecosystem CO 2 absorption. The frequent alternate wet-dry cycles of CI paddy fields increased the soil respiration and reduced the net CO 2 absorption. Organic fertilizer promoted the soil respiration of paddy soil but also increased its net CO 2 absorption and organic carbon content. Therefore, the joint regulation of water-saving irrigation and organic fertilizer is an effective measure for maintaining yield, increasing irrigation water use efficiency, mitigating CO 2 emission, and promoting paddy soil fertility.

How Well Do SiF And Other Vegetation Spectral Indices Track Temporal Variations of Canopy Photosynthesis in A Paddy Rice

NASA Astrophysics Data System (ADS)

Kaige, Y.; Ryu, Y.; Kimm, H.; Huang, Y.; Jiang, C.; Hwang, Y.; Kim, J.; Kang, M.

2016-12-01

Recent advancements in remote sensing of SiF opened new opportunities to directly estimate canopy photosynthesis at regional scales. Observing SiF at canopy scale in the field, however, is at very initial stage. In this study, we report SiF and hyperspectral reflectance (400-900 nm) data concurrently measured every 10 sec across the whole growing season in a paddy rice, South Korea. The study site experienced water management via irrigation and drainage and showed a peak LAI of 7. We test whether SiF and a range of different vegetation spectral indices (VIs) well capture half-hourly variations in canopy photosynthesis quantified from an eddy flux tower. During the growing season, we found that SiF showed tight linear relationship to APAR (r2=0.7), and moderate linear relationship to GPP (r2=0.5). Both NDVI, EVI and PRI showed logarithmic relationships to GPP (r2<0.5) and were all saturated at LAI>4. SiF showed linear relationship to GPP even at higher LAI. We conclude that SiF is a better index in predicting temporal variations in canopy photosynthesis than the other VIs in the paddy rice site.

Paddy farmer households’ participation and food security level in special effort program in Seputih Raman sub-district of Central Lampung Regency

NASA Astrophysics Data System (ADS)

Rangga, K. K.; Syarief, Y. A.

2018-03-01

The objectives of this study are to study the participation of paddy farmers in the Special Effort program to increase paddy production, to study the level of household food security of paddy farmers, and to analyze the correlation between farmer participation and food security level of paddy farmers. The location was chosen purposively in Seputih Raman sub-district. The data were collected from December 2016 to February 2017. The population of this study was paddy farmers who participating in Special Effort program. The hypothesis was tested by using Spearman’s Rank correlation test. Farmer household’s food security was measured objectively based on the share of household’s food expenditure and subjectively based on the opinion, views, and attitudes or farmers’ opinions on food availability, food distribution, and household food consumption. This research showed that farmers’ participation in Special Effort program in Seputih Raman Sub Ditrict, Central Lampung Regency belonged to medium classification, household food security either objectively or subjectively was in food resistant condition of medium classification, and there was significant correlation between farmers’ participation and food security level of paddy farmer household.

Global Rice Watch: Spatial-temporal dynamics, driving factors, and impacts of paddy rice agriculture in the world

NASA Astrophysics Data System (ADS)

Xiao, X.; Dong, J.; Zhang, G.; Xin, F.; Li, X.

2017-12-01

Paddy rice croplands account for more than 12% of the global cropland areas, and provide food to feed more than 50% of the world population. Spatial patterns and temporal dynamics of paddy rice croplands have changed remarkably in the past decades, driven by growing human population and their changing diet structure, land use (e.g., urbanization, industrialization), climate, markets, and technologies. In this presentation, we will provide a comprehensive review of our current knowledge on (1) the spatial patterns and temporal dynamics of paddy rice croplands from agricultural statistics data and remote sensing approaches; (2) major driving factors for the observed changes in paddy rice areas, including social, economic, climate, land use, markets, crop breeding technology, and farming technology; and (3) major impacts on atmospheric methane concentration, land surface temperature, water resources and use, and so on. We will highlight the results from a few case studies in China and monsoon Asia. We will also call for a global synthesis analysis of paddy rice agriculture, and invite researchers to join the effort to write and edit a book that provides comprehensive and updated knowledge on paddy rice agriculture.

Effects of seed mixture sowing with resistant and susceptible rice on population dynamics of target planthoppers and non-target stemborers and leaffolders.

PubMed

Li, Zhuo; Wan, Guijun; Wang, Long; Parajulee, Megha N; Zhao, Zihua; Chen, Fajun

2018-07-01

The widespread planting of insect-resistant crops has caused a dramatic shift in agricultural landscapes, thus raising concerns about the potential impact on both target and non-target pests worldwide. In this study, we examined the potential effects of six seed mixture ratios of insect-resistance dominance [100% (R100), 95% (S05R95), 90% (S10R90), 80% (S20R80), 60% (S40R60), and 0% (S100)] on target and non-target pests in a 2-year field trial in southern China. The occurrence of the target pests Nilaparvata lugens and Sogatella furcifera decreased with an increase in the ratio of resistant rice, and mixture ratios with ≥90% resistant rice significantly increased the pest suppression efficiency, with the lowest occurrences of the non-target pests Sesamia inferens, Chilo suppressalis and Cnaphalocrocis medinalis for S100 and S10R90 seed mixture ratios. Furthermore, there were no significant differences in the 1000-grain dry weight and grain yield between R100 and other treatments with ≥80% resistant seeds in the mixture (S20R80, S10R90 and S05R95). S10R90 produced a good yield and provided the most effective control of both target and non-target pests, with the potential to significantly reduce the application of chemical pesticides for integrated pest management in paddy fields. It is further presumed that the strategy of seed mixture with resistant and susceptible rice would be advantageous for rice yield stability. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Ammonia Volatilization from Urea-Application Influenced Germination and Early Seedling Growth of Dry Direct-Seeded Rice

PubMed Central

Qi, Xiaoli; Wu, Wei; Shah, Farooq; Peng, Shaobing; Huang, Jianliang; Cui, Kehui; Liu, Hongyan; Nie, Lixiao

2012-01-01

Poor seed germination and early seedling growth associated with urea-induced soil ammonia volatilization are major constraints in the adoption of dry direct-seeded rice. To directly examine soil ammonia volatilization and its damage to seed germination and early seedling growth of dry direct-seeded rice when urea is applied at seeding, two Petri-dish incubation experiments and a field experiment were conducted. Ammonia volatilization due to urea application significantly reduced seed germination and early seedling growth of dry direct-seedling rice. NBPT significantly reduced ammonia volatilization following urea application. The application of ammonium sulfate, instead of urea at seeding, may mitigate poor crop establishment of dry direct-seeded rice. Root growth of dry direct-seeded rice was more seriously inhibited by soil ammonia volatilization than that of shoot. Results suggest that roots are more sensitive to soil ammonia toxicity than shoots in dry direct-seeded rice system when N is applied as urea at seeding. PMID:22454611

Study on paddy rice yield estimation based on multisource data and the Grey system theory

NASA Astrophysics Data System (ADS)

Deng, Wensheng; Wang, Wei; Liu, Hai; Li, Chen; Ge, Yimin; Zheng, Xianghua

2009-10-01

The paddy rice is our important crops. In study of the paddy rice yield estimation, compared with the scholars who usually only take the remote sensing data or meteorology as the influence factors, we combine the remote sensing and the meteorological data to make the monitoring result closer reality. Although the gray system theory has used in many aspects, it is applied very little in paddy rice yield estimation. This study introduces it to the paddy rice yield estimation, and makes the yield estimation model. This can resolve small data sets problem that can not be solved by deterministic model. It selects some regions in Jianghan plain for the study area. The data includes multi-temporal remote sensing image, meteorological and statistic data. The remote sensing data is the 16-day composite images (250-m spatial resolution) of MODIS. The meteorological data includes monthly average temperature, sunshine duration and rain fall amount. The statistical data is the long-term paddy rice yield of the study area. Firstly, it extracts the paddy rice planting area from the multi-temporal MODIS images with the help of GIS and RS. Then taking the paddy rice yield as the reference sequence, MODIS data and meteorological data as the comparative sequence, computing the gray correlative coefficient, it selects the yield estimation factor based on the grey system theory. Finally, using the factors, it establishes the yield estimation model and does the result test. The result indicated that the method is feasible and the conclusion is credible. It can provide the scientific method and reference value to carry on the region paddy rice remote sensing estimation.

Assessment of heavy metals (Cd and Pb) and micronutrients (Cu, Mn, and Zn) of paddy (Oryza sativa L.) field surface soil and water in a predominantly paddy-cultivated area at Puducherry (Pondicherry, India), and effects of the agricultural runoff on the elemental concentrations of a receiving rivulet.

PubMed

Reddy, M Vikram; Satpathy, Deepmala; Dhiviya, K Shyamala

2013-08-01

The concentrations of toxic heavy metals-Cd and Pb and micronutrients-Cu, Mn, and Zn were assessed in the surface soil and water of three different stages of paddy (Oryza sativa L.) fields, the stage I-the first stage in the field soon after transplantation of the paddy seedlings, holding adequate amount of water on soil surface, stage II-the middle stage with paddy plants of stem of about 40 cm length, with sufficient amount of water on the soil surface, and stage III-the final stage with fully grown rice plants and very little amount of water in the field at Bahour, a predominantly paddy cultivating area in Puducherry located on the southeast Coast of India. Comparison of the heavy metal and micronutrient concentrations of the soil and water across the three stages of paddy field showed their concentrations were significantly higher in soil compared with that of water (p < 0.05) of the fields probably because of accumulation and adsorption in soil. The elemental concentrations in paddy soil as well as water was in the ranking order of Cd > Mn > Zn > Cu > Pb indicating concentration of Cd was maximum and Pb was minimum. The elemental concentrations in both soil and water across the three stages showed a ranking order of stage II > stage III > stage I. The runoff from the paddy fields has affected the elemental concentrations of the water and sediment of an adjacent receiving rivulet.

Effect of mixed soil microbiomes on pyrene removal and the response of the soil microorganisms.

PubMed

Wang, Beibei; Teng, Ying; Xu, Yongfeng; Chen, Wei; Ren, Wenjie; Li, Yan; Christie, Peter; Luo, Yongming

2018-05-28

Mixed soil microbiomes were established by introducing aliquots of a paddy soil into a red soil. The new mixed microbiomes effectively metabolized high-molecular-weight polycyclic aromatic hydrocarbons (PAHs, pyrene) in the soil mixtures. The pyrene removal efficiencies were 19% and 98%, respectively, in the original red soil and the paddy soil. The pyrene removal effectiveness by the mixed microbial community was enhanced by increasing the amount of paddy soil inoculant and the pyrene removal rates were 93%, 58% and 27% in paddy soil/red soil mixtures of 1:1, 3:7 and 1:9 (w/w), respectively. Supplementation with sterile paddy soil and nutrients changed the soil environment but the pyrene removal efficiency was not enhanced, indicating that the microbial composition largely determined the extent of pyrene removal. Moreover, the pyrene removal rate was positively related to the pyrene dioxygenase gene (nidA) abundance. The greater the percentage of the paddy soil in the soil mixture the greater the similarity of the mixed microbiome to that of the original paddy soil itself. The community of the inoculated sterile paddy soil was similar to that of the red soil and the community diverged from those of the red soil and the paddy soil with increasing culture time. After culture for 42 days, some enriched genera were responsible for PAH degradation, notably Nevskia, Ralstonia, Gemmatimonas and Lysobacter, while some genera have no clear classification information or category name at the genus level, such as f__Acidobacteriaceae and o__JG30-KF-AS9. This study is very important in recognizing the role of natural soil in the formation of a mixed microbiome to stimulate the degradation of PAHs in a soil with low intrinsic PAH degradation capability. Copyright © 2018 Elsevier B.V. All rights reserved.

A comparison of methane emissions following rice paddies conversion to crab-fish farming wetlands in southeast China.

PubMed

Hu, Zhiqiang; Wu, Shuang; Ji, Cheng; Zou, Jianwen; Zhou, Quansuo; Liu, Shuwei

2016-01-01

Rice paddies and aquaculture wetlands are typical agricultural wetlands that constitute one of the important sources of atmospheric methane (CH4). Traditional transplanted rice paddies have been experiencing conversion to pond aquaculture wetlands for pursuing higher economic benefits over the past decades in southeast China. A parallel field experiment was carried out to compare CH4 emissions from a transplanted rice paddy and its converted crab-fish farming wetland in southeast China. Over the rice-growing season, CH4 fluxes averaged 1.86 mg m(-2) h(-1) from rice paddies, and 1.14 and 0.50 mg m(-2) h(-1) for the treatments with or without aquatic vegetation present in the crab-fish farming wetlands, respectively. When averaged across the treatments, seasonal CH4 emissions from crab-fish framing wetlands were 52% lower than those from rice paddies. The CH4 fluxes were negatively related to water dissolved oxygen (DO) concentration but positively related to soil/sediment dissolved organic carbon (DOC) content in crab-fish farming wetlands. Dependence of CH4 fluxes on DO or DOC was intensified by the aquatic vegetation presence. By extrapolating the present CH4 emission rate with the current rice paddy-converted aquaculture cultivation area, the seasonal CH4 emissions from inland aquaculture wetlands during the critical farming stage (20 June to 18 October) were estimated to be 33.6 Gg ha(-1) in southeast China in 2012. Rice paddies conversion to crab-fish farming wetlands might have reduced CH4 emissions by 22-54% in mainland China. Results of this study suggest that the conversion of transplanted rice paddies to crab-fish aquaculture wetlands for higher economic benefits would also lead to a lower ecosystem CH4 release rate.

Mapping paddy rice planting areas through time series analysis of MODIS land surface temperature and vegetation index data

PubMed Central

Zhang, Geli; Xiao, Xiangming; Dong, Jinwei; Kou, Weili; Jin, Cui; Qin, Yuanwei; Zhou, Yuting; Wang, Jie; Menarguez, Michael Angelo; Biradar, Chandrashekhar

2016-01-01

Knowledge of the area and spatial distribution of paddy rice is important for assessment of food security, management of water resources, and estimation of greenhouse gas (methane) emissions. Paddy rice agriculture has expanded rapidly in northeastern China in the last decade, but there are no updated maps of paddy rice fields in the region. Existing algorithms for identifying paddy rice fields are based on the unique physical features of paddy rice during the flooding and transplanting phases and use vegetation indices that are sensitive to the dynamics of the canopy and surface water content. However, the flooding phenomena in high latitude area could also be from spring snowmelt flooding. We used land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to determine the temporal window of flooding and rice transplantation over a year to improve the existing phenology-based approach. Other land cover types (e.g., evergreen vegetation, permanent water bodies, and sparse vegetation) with potential influences on paddy rice identification were removed (masked out) due to their different temporal profiles. The accuracy assessment using high-resolution images showed that the resultant MODIS-derived paddy rice map of northeastern China in 2010 had a high accuracy (producer and user accuracies of 92% and 96%, respectively). The MODIS-based map also had a comparable accuracy to the 2010 Landsat-based National Land Cover Dataset (NLCD) of China in terms of both area and spatial pattern. This study demonstrated that our improved algorithm by using both thermal and optical MODIS data, provides a robust, simple and automated approach to identify and map paddy rice fields in temperate and cold temperate zones, the northern frontier of rice planting. PMID:27667901

Mapping paddy rice planting areas through time series analysis of MODIS land surface temperature and vegetation index data.

PubMed

Zhang, Geli; Xiao, Xiangming; Dong, Jinwei; Kou, Weili; Jin, Cui; Qin, Yuanwei; Zhou, Yuting; Wang, Jie; Menarguez, Michael Angelo; Biradar, Chandrashekhar

2015-08-01

Knowledge of the area and spatial distribution of paddy rice is important for assessment of food security, management of water resources, and estimation of greenhouse gas (methane) emissions. Paddy rice agriculture has expanded rapidly in northeastern China in the last decade, but there are no updated maps of paddy rice fields in the region. Existing algorithms for identifying paddy rice fields are based on the unique physical features of paddy rice during the flooding and transplanting phases and use vegetation indices that are sensitive to the dynamics of the canopy and surface water content. However, the flooding phenomena in high latitude area could also be from spring snowmelt flooding. We used land surface temperature (LST) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to determine the temporal window of flooding and rice transplantation over a year to improve the existing phenology-based approach. Other land cover types (e.g., evergreen vegetation, permanent water bodies, and sparse vegetation) with potential influences on paddy rice identification were removed (masked out) due to their different temporal profiles. The accuracy assessment using high-resolution images showed that the resultant MODIS-derived paddy rice map of northeastern China in 2010 had a high accuracy (producer and user accuracies of 92% and 96%, respectively). The MODIS-based map also had a comparable accuracy to the 2010 Landsat-based National Land Cover Dataset (NLCD) of China in terms of both area and spatial pattern. This study demonstrated that our improved algorithm by using both thermal and optical MODIS data, provides a robust, simple and automated approach to identify and map paddy rice fields in temperate and cold temperate zones, the northern frontier of rice planting.

21 CFR 882.4700 - Neurosurgical paddie.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Neurosurgical paddie. 882.4700 Section 882.4700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4700 Neurosurgical paddie. (a) A...

21 CFR 882.4700 - Neurosurgical paddie.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Neurosurgical paddie. 882.4700 Section 882.4700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4700 Neurosurgical paddie. (a) A...

Northward expansion of paddy rice in northeastern Asia during 2000-2014

NASA Astrophysics Data System (ADS)

Dong, J.; Xiao, X.; Zhang, G.; Menarguez, M. A.; Choi, C. Y.; Qin, Y.; Luo, P.; Zhang, Y.; Moore, B.

2016-04-01

Paddy rice in monsoon Asia plays an important role in global food security and climate change. Here we documented annual dynamics of paddy rice areas in the northern frontier of Asia, including northeastern (NE) China, North Korea, South Korea, and Japan, from 2000 to 2014 through analysis of satellite images. The paddy rice area has increased by 120% (2.5 to 5.5 million ha) in NE China, in comparison to a decrease in South Korea and Japan, and the paddy rice centroid shifted northward from 41.16°N to 43.70°N (~310 km) in this period. Market, technology, policy, and climate together drove the rice expansion in NE China. The increased use of greenhouse nurseries, improved rice cultivars, agricultural subsidy policy, and a rising rice price generally promoted northward paddy rice expansion. The potential effects of large rice expansion on climate change and ecosystem services should be paid more attention to in the future.

Fate of 14C-labeled dissolved organic matter in paddy and upland soils in responding to moisture.

PubMed

Chen, Xiangbi; Wang, Aihua; Li, Yang; Hu, Lening; Zheng, Hua; He, Xunyang; Ge, Tida; Wu, Jinshui; Kuzyakov, Yakov; Su, Yirong

2014-08-01

Soil organic matter (SOM) content in paddy soils is higher than that in upland soils in tropical and subtropical China. The dissolved organic matter (DOM) concentration, however, is lower in paddy soils. We hypothesize that soil moisture strongly controls the fate of DOM, and thereby leads to differences between the two agricultural soils under contrasting management regimens. A 100-day incubation experiment was conducted to trace the fate and biodegradability of DOM in paddy and upland soils under three moisture levels: 45%, 75%, and 105% of the water holding capacity (WHC). (14)C labeled DOM, extracted from the (14)C labeled rice plant material, was incubated in paddy and upland soils, and the mineralization to (14)CO2 and incorporation into microbial biomass were analyzed. Labile and refractory components of the initial (14)C labeled DOM and their respective half-lives were calculated by a double exponential model. During incubation, the mineralization of the initial (14)C labeled DOM in the paddy soils was more affected by moisture than in the upland soils. The amount of (14)C incorporated into the microbial biomass (2.4-11.0% of the initial DOM-(14)C activity) was less affected by moisture in the paddy soils than in the upland soils. At any of the moisture levels, 1) the mineralization of DOM to (14)CO2 within 100 days was 1.2-2.1-fold higher in the paddy soils (41.9-60.0% of the initial DOM-(14)C activity) than in the upland soils (28.7-35.7%), 2) (14)C activity remaining in solution was significantly lower in the paddy soils than in the upland soils, and 3) (14)C activity remaining in the same agricultural soil solution was not significantly different among the three moisture levels after 20 days. Therefore, moisture strongly controls DOM fate, but moisture was not the key factor in determining the lower DOM in the paddy soils than in the upland soils. The UV absorbance of DOM at 280 nm indicates less aromaticity of DOM from the paddy soils than from the upland soils. At any of the moisture levels, much more labile DOM was found in paddy soils (34.3-49.2% of the initial (14)C labeled DOM) compared with that in upland soils (19.4-23.9%). This demonstrates that the lower DOM content in the paddy soil compared with that in the upland soil is probably determined by the less complex components and structure of the DOM. Copyright © 2014 Elsevier B.V. All rights reserved.

Effects of changing redox conditions on the dynamics of dissolved organic matter and CO2 in paddy soils

NASA Astrophysics Data System (ADS)

Hanke, Alexander; Cao, Zhi Hong; Liu, Qin; Muhr, Jan; Kalbitz, Karsten

2010-05-01

The current knowledge about dissolved organic matter (DOM) dynamics in soils and its dependence on different C pools based mainly on observations and experiments in aerobic environments. We have only a limited understanding about the effects of changing redox conditions on production and composition of DOM although this fraction of soil organic matter is important for greenhouse gas emission and carbon storage in soils. In many ecosystems temporal and spatial changes of oxic and anoxic conditions are evident and might even increase in future. It is assumed that changing redox conditions are the key drivers of DOM dynamics in such ecosystems. More detailed we tested the following hypotheses: Anoxic conditions result in relative DOM accumulation due to less mineralization of already produced DOM Close relationship between DOM production and CO2 emission 14C signature of CO2 enables the identification of different C pools degraded at oxic and anoxic conditions We chose paddy soils as a model ecosystem because these soils are anoxic during the rice growing period and oxic during harvest and growth of other crops. Furthermore, paddy soils have oxic and anoxic horizons. Soils of a unique chronosequence of paddy soil evolution (50 to 2000 years, China) were studied in direct comparison to non-paddy soils of the same age. In these soils, exposed to different redox conditions over defined periods of times, the dynamics of DOM, CO2, 14C of the CO2 and other redox sensitive elements were followed in laboratory experiments. In the latter redox conditions were changed every 3 weeks from oxic to anoxic and vice versa. Besides analysis of the composition of the soil solution and the gas phase we determined differences in C pools being respired at oxic and anoxic conditions by 14C AMS of the CO2. The measured redox potentials of -50 mV to 250mV at anoxic conditions and 350 mV to 550 mV at oxic conditions were in the expected range and proofed the appropriate setting of the chosen incubation method. PH values varied between 5.5 and 7.5, where anoxic samples had higher values than oxic ones. We further observed only small DOC contents of less than 1mg per g C. Under anoxic conditions as well as among the non-paddy soils DOC production was slightly higher than their respective counterparts. However, we could not find large effects of the time of rice cultivation. Nevertheless, the 2000 year old paddy soil showed highest DOC and CO2 production. The increase of DOC and CO2 production was strongest when the oxic period disrupted the anoxic conditions. 14C data revealed that CO2 respired from the 700 year old paddy soil was much older than from the 2000 year old paddy soil independently from redox condition. Furthermore, C mineralized at anoxic conditions was older than at oxic ones. During the incubation experiment the C consumption shifted from older pools to younger ones. We conclude that DOM accumulated at anoxic conditions will be quickly mineralized at oxic conditions. The influence of soil development on the C dynamics was less important than expected, thus fresh organic matter seems to play a more decisive role. The unexpected large decomposition of old organic matter at anoxic conditions hints to changes in the microbial community involved.

Object-Based Paddy Rice Mapping Using HJ-1A/B Data and Temporal Features Extracted from Time Series MODIS NDVI Data

PubMed Central

Singha, Mrinal; Wu, Bingfang; Zhang, Miao

2016-01-01

Accurate and timely mapping of paddy rice is vital for food security and environmental sustainability. This study evaluates the utility of temporal features extracted from coarse resolution data for object-based paddy rice classification of fine resolution data. The coarse resolution vegetation index data is first fused with the fine resolution data to generate the time series fine resolution data. Temporal features are extracted from the fused data and added with the multi-spectral data to improve the classification accuracy. Temporal features provided the crop growth information, while multi-spectral data provided the pattern variation of paddy rice. The achieved overall classification accuracy and kappa coefficient were 84.37% and 0.68, respectively. The results indicate that the use of temporal features improved the overall classification accuracy of a single-date multi-spectral image by 18.75% from 65.62% to 84.37%. The minimum sensitivity (MS) of the paddy rice classification has also been improved. The comparison showed that the mapped paddy area was analogous to the agricultural statistics at the district level. This work also highlighted the importance of feature selection to achieve higher classification accuracies. These results demonstrate the potential of the combined use of temporal and spectral features for accurate paddy rice classification. PMID:28025525

Carbon Dioxide Flux from Rice Paddy Soils in Central China: Effects of Intermittent Flooding and Draining Cycles

PubMed Central

Liu, Yi; Wan, Kai-yuan; Tao, Yong; Li, Zhi-guo; Zhang, Guo-shi; Li, Shuang-lai; Chen, Fang

2013-01-01

A field experiment was conducted to (i) examine the diurnal and seasonal soil carbon dioxide (CO2) fluxes pattern in rice paddy fields in central China and (ii) assess the role of floodwater in controlling the emissions of CO2 from soil and floodwater in intermittently draining rice paddy soil. The soil CO2 flux rates ranged from −0.45 to 8.62 µmol.m−2.s−1 during the rice-growing season. The net effluxes of CO2 from the paddy soil were lower when the paddy was flooded than when it was drained. The CO2 emissions for the drained conditions showed distinct diurnal variation with a maximum efflux observed in the afternoon. When the paddy was flooded, daytime soil CO2 fluxes reversed with a peak negative efflux just after midday. In draining/flooding alternating periods, a sudden pulse-like event of rapidly increasing CO2 efflux occured in response to re-flooding after draining. Correlation analysis showed a negative relation between soil CO2 flux and temperature under flooded conditions, but a positive relation was found under drained conditions. The results showed that draining and flooding cycles play a vital role in controlling CO2 emissions from paddy soils. PMID:23437170

Risk assessment of lambda-cyhalothrin on aquatic organisms in paddy field in China.

PubMed

Gu, Bao G; Wang, Hui M; Chen, William L; Cai, Dao J; Shan, Zheng J

2007-06-01

This study was carried out to assess the risk of lambda-cyhalothrin to aquatic organisms used in paddy field, and to provide assistance in the ecological risk management of lambda-cyhalothrin. The acute toxicities of five individual formulations of lambda-cyhalothrin to four aquatic species were investigated in the laboratory, as well as in a simulated paddy field-pond ecosystem, and the results implicated that lambda-cyhalothrin is highly toxic to fish, and to a greater extent to shrimp. There were differences in the toxicities to each aquatic organisms among different formulations. lambda-Cyhalothrin degraded rapidly in the environment, with half-lives of different formulations in paddy field water (0.23-0.53 days), pond water (0.38-0.63 days), and paddy field soil (0.96-7.35 days), respectively. The water overflow from the paddy field following a simulated rainstorm 12h after application of lambda-cyhalothrin did not cause injury to fish, clam or crab, but was severely hazardous to shrimp. Additionally, no injury to shrimp was found when simulated overflow occurred 4 days after application. These results suggest that the environmental risk of lambda-cyhalothrin to aquatic organisms can be reduced by (1) developing a relatively safe formulation such as a suspension concentrate, and/or (2) controlling the drainage time of the paddy field.

Enhancing Nitrogen Availability, Ammonium Adsorption-Desorption, and Soil pH Buffering Capacity using Composted Paddy Husk

NASA Astrophysics Data System (ADS)

Latifah, O.; Ahmed, O. H.; Abdul Majid, N. M.

2017-12-01

Form of nitrogen present in soils is one of the factors that affect nitrogen loss. Nitrate is mobile in soils because it does not absorb on soil colloids, thus, causing it to be leached by rainfall to deeper soil layers or into the ground water. On the other hand, temporary retention and timely release of ammonium in soils regulate nitrogen availability for crops. In this study, composted paddy husk was used in studies of soil leaching, buffering capacity, and ammonium adsorption and desorption to determine the: (i) availability of exchangeable ammonium, available nitrate, and total nitrogen in an acid soil after leaching the soil for 30 days, (ii) soil buffering capacity, and (iii) ability of the composted paddy husk to adsorb and desorb ammonium from urea. Leaching of ammonium and nitrate were lower in all treatments with urea and composted paddy husk compared with urea alone. Higher retention of soil exchangeable ammonium, available nitrate, and total nitrogen of the soils with composted paddy husk were due to the high buffering capacity and cation exchange capacity of the amendment to adsorb ammonium thus, improving nitrogen availability through temporary retention on the exchange sites of the humic acids of the composted paddy husk. Nitrogen availability can be enhanced if urea is amended with composted paddy husk.

Object-Based Paddy Rice Mapping Using HJ-1A/B Data and Temporal Features Extracted from Time Series MODIS NDVI Data.

PubMed

Singha, Mrinal; Wu, Bingfang; Zhang, Miao

2016-12-22

Accurate and timely mapping of paddy rice is vital for food security and environmental sustainability. This study evaluates the utility of temporal features extracted from coarse resolution data for object-based paddy rice classification of fine resolution data. The coarse resolution vegetation index data is first fused with the fine resolution data to generate the time series fine resolution data. Temporal features are extracted from the fused data and added with the multi-spectral data to improve the classification accuracy. Temporal features provided the crop growth information, while multi-spectral data provided the pattern variation of paddy rice. The achieved overall classification accuracy and kappa coefficient were 84.37% and 0.68, respectively. The results indicate that the use of temporal features improved the overall classification accuracy of a single-date multi-spectral image by 18.75% from 65.62% to 84.37%. The minimum sensitivity (MS) of the paddy rice classification has also been improved. The comparison showed that the mapped paddy area was analogous to the agricultural statistics at the district level. This work also highlighted the importance of feature selection to achieve higher classification accuracies. These results demonstrate the potential of the combined use of temporal and spectral features for accurate paddy rice classification.

Field investigation to assess nutrient emission from paddy field to surface water in river catchment

NASA Astrophysics Data System (ADS)

Kogure, Kanami; Aichi, Masaatsu; Zessner, Matthias

2015-04-01

In order to maintain good river environment, it is remarkably important to understand and to control nutrient behavior such as Nitrogen and Phosphorus. Our former research dealing with nutrient emission analysis in the Tone River basin area in Japan, in addition to urban and industrial waste water, nutrient emission from agricultural activity is dominant pollution source into the river system. Japanese style agriculture produces large amount of rice and paddy field occupies large areas in Japanese river basin areas. While paddy field can deteriorate river water quality by outflow of fertilizer, it is also suggested that paddy field has water purification function. As we carried out investigation in the Tone River Basin area, data were obtained which dissolved nitrogen concentration is lower in discharging water from paddy field than inflowing water into the field. Regarding to nutrient emission impact from paddy field, sufficient data are required to discuss quantitatively seasonal change of material behavior including flooding season and dry season, difference of climate condition, soil type, and rice species, to evaluate year round comprehensive impact from paddy field to the river system. In this research, field survey in paddy field and data collection relating rice production were carried out as a preliminary investigation to assess how Japanese style paddy field contributes year round on surface water quality. Study sites are three paddy fields located in upper reach of the Tone River basin area. The fields are flooded from June to September. In 2014, field investigations were carried out three times in flooding period and twice in dry period. To understand characteristics of each paddy field and seasonal tendency accompanying weather of agricultural event, short term investigations were conducted and we prepare for further long term investigation. Each study site has irrigation water inflow and outflow. Two sites have tile drainage system under the field and TD water can be sampled for infiltrating water measurement. We installed monitoring wells to measure ground water level and water quality. Inflow, outflow, flooding water, infiltrating water, and ground water were measured and sampled. Regarding to parameters, temperature, pH, EC, DO and COD, main ions were measured to understand characteristic of water quality and transformation processes. Inorganic forms of nitrogen and phosphorus were also measured, as behavior and balance of nitrogen and phosphorus are focused on. We observed following points by taking data of water quality; seasonal trend, changes occurred according to agricultural events like irrigation and fertilization. Nitrogen in ground water tends to high in June due to fertilizer. It is thought because farmers fertilize the filed before transplanting at the beginning of flooding season. Regarding to dissolved inorganic nitrogen, higher concentrations were observed in inflow water than in flooding water and outflow water. Though it needs discussion in loads as well as flow measurement, this suggests that nutrients are absorbed in paddy field and less nutrients are emitted after irrigation water passing through paddy field. Based on this research we are planning continuous investigation to assess environmental impact from paddy field.

Estimation of the rice-planting field in Bangladesh by satellite remote sensing

NASA Astrophysics Data System (ADS)

Furuta, E.; Suzuki, G.; Yamassaki, M.; Teraoka, T.; Fujiwara, H.; Ogino, Y.; Akashi, M.; Lahrita, L.; Naruse, N.; Takahashi, Y.

2016-12-01

In Bangladesh, price of rice has been unstable due to a large increase in production. To control the price can become a political issue, because rice agriculture is one of the most important industries in Bangladesh, whereas the total area of the paddy field is accurately unknown, owing to unsustainable and on-site surveys for the area (1). Satellite remote sensing is an effective solution to research the all area of domestic paddy field. Microwave satellite imaging has a large merit to be observable regardless of the weather conditions, however, research institutions have been limited to observing continuously since the cost is high for developing countries, such as Bangladesh. This study aims to establish the way to grasp the paddy field using optical satellite images for free of charge (Landsat-8). We have focused on seasonal changes in the water and the vegetation indices obtained from paddy fields. We have performed image calculations of Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) of the well-known paddy field in Bangladesh Rice Research Institute. We found that there are seasonal changes of NDVI and NDWI calculated from paddy field. The characteristics are as follows; the NDVI and the NDWI values varies by 0.17-0.25 up and 0.11-0.19 down, respectively, at the transition from the dry to the rainy season, on the other hand, the NDVI and the NDWI changes by 0.21-0.29 down and 0.09-0.17 up from the rainy to the dry season. These features make us to distinguish the paddy field from the other cultivated area. The decrease of NDVI means that rice bares, The increase of NDWI can be interpreted that the paddy field is covered with water for the preparation for planting it. Our estimated area of paddy field in Bangladesh (85,900km ) corresponds well with the previous reported value of 117,700km (1). We have established the way to grasp the paddy field using optical satellite images for free of charge, on the bases of the seasonal changes of NDVI and NDWI. Ref: 1.FAOSTAT 2013

Effects of water management, connectivity, and surrounding land use on habitat use by frogs in rice paddies in Japan.

PubMed

Naito, Risa; Yamasaki, Michimasa; Lmanishi, Ayumi; Natuhara, Yosihiro; Morimoto, Yukihiro

2012-09-01

In Japan, rice paddies play an important role as a substitute habitat for wetland species, and support rich indigenous ecosystems. However, since the 1950s, agricultural modernization has altered the rice paddy environment, and many previously common species are now endangered. It is urgently necessary to evaluate rice paddies as habitats for conservation. Among the species living in rice paddies, frogs are representative and are good indicator species, so we focused on frog species and analyzed the influence of environmental factors on their habitat use. We found four frog species and one subspecies (Hyla japonica, Pelophylax nigromaculatus, Glandirana rugosa, Lithobates catesbeianus, and Pelophylax porosa brevipoda) at our study sites in Shiga prefecture. For all but L. catesbeianus, we analyzed the influence of environmental factors related to rice paddy structure, water management and availability, agrochemical use, connectivity, and land use on breeding and non-breeding habitat use. We constructed generalized additive mixed models with survey date as the smooth term and applied Akaike's information criterion to choose the bestranked model. Because life histories and biological characteristics vary among species, the factors affecting habitat use by frogs are also expected to differ by species. We found that both breeding and non-breeding habitat uses of each studied species were influenced by different combinations of environmental factors and that in most cases, habitat use showed seasonality. For frog conservation in rice paddies, we need to choose favorable rice paddy in relation to surrounding land use and apply suitable management for target species.

Global rain-fed, irrigated, and paddy croplands: A new high resolution map derived from remote sensing, crop inventories and climate data

NASA Astrophysics Data System (ADS)

Salmon, J. Meghan; Friedl, Mark A.; Frolking, Steve; Wisser, Dominik; Douglas, Ellen M.

2015-06-01

Irrigation accounts for 70% of global water use by humans and 33-40% of global food production comes from irrigated croplands. Accurate and timely information related to global irrigation is therefore needed to manage increasingly scarce water resources and to improve food security in the face of yield gaps, climate change and extreme events such as droughts, floods, and heat waves. Unfortunately, this information is not available for many regions of the world. This study aims to improve characterization of global rain-fed, irrigated and paddy croplands by integrating information from national and sub-national surveys, remote sensing, and gridded climate data sets. To achieve this goal, we used supervised classification of remote sensing, climate, and agricultural inventory data to generate a global map of irrigated, rain-fed, and paddy croplands. We estimate that 314 million hectares (Mha) worldwide were irrigated circa 2005. This includes 66 Mha of irrigated paddy cropland and 249 Mha of irrigated non-paddy cropland. Additionally, we estimate that 1047 Mha of cropland are managed under rain-fed conditions, including 63 Mha of rain-fed paddy cropland and 985 Mha of rain-fed non-paddy cropland. More generally, our results show that global mapping of irrigated, rain-fed, and paddy croplands is possible by combining information from multiple data sources. However, regions with rapidly changing irrigation or complex mixtures of irrigated and non-irrigated crops present significant challenges and require more and better data to support high quality mapping of irrigation.

Development of an Improved Irrigation Subroutine in SWAT to Simulate the Hydrology of Rice Paddy Grown under Submerged Conditions

NASA Astrophysics Data System (ADS)

Muraleedharan, B. V.; Kathirvel, K.; Narasimhan, B.; Nallasamy, N. D.

2014-12-01

Soil Water Assessment Tool (SWAT) is a basin scale, distributed hydrological model commonly used to predict the effect of management decisions on the hydrologic response of watersheds. Hydrologic response is decided by the various components of water balance. In the case of watersheds located in south India as well as in several other tropical countries around the world, paddy is one of the dominant crop controlling the hydrologic response of a watershed. Hence, the suitability of SWAT in replicating the hydrology of paddy fields needs to be verified. Rice paddy fields are subjected to flooding method of irrigation, while the irrigation subroutines in SWAT are developed to simulate crops grown under non flooding conditions. Moreover irrigation is represented well in field scale models, while it is poorly represented within watershed models like SWAT. Reliable simulation of flooding method of irrigation and hydrology of the fields will assist in effective water resources management of rice paddy fields which are one of the major consumers of surface and ground water resources. The current study attempts to modify the irrigation subroutine in SWAT so as to simulate flooded irrigation condition. A field water balance study was conducted on representative fields located within Gadana, a subbasin located in Tamil Nadu (southern part of India) and dominated by rice paddy based irrigation systems. The water balance of irrigated paddy fields simulated with SWAT was compared with the water balance derived by rice paddy based crop growth model named ORYZA. The variation in water levels along with the soil moisture variation predicted by SWAT was evaluated with respect to the estimates derived from ORYZA. The water levels were further validated with field based water balance measurements taken on a daily scale. It was observed that the modified irrigation subroutine was able to simulate irrigation of rice paddy within SWAT in a realistic way compared to the existing method.

Changes of paddy rice planting areas in Northeastern Asia from 1986 to 2014 based on Landsat data

NASA Astrophysics Data System (ADS)

Dong, J.; Xiao, X.; Kou, W.; Qin, Y.; Wang, J.; Zhang, G.; Jin, C.; Zhou, Y.; Menarguez, M. A.; Moore, B., III

2014-12-01

Paddy rice is an important cereal crop and main grain source for more than half of the global human population. However, knowledge about its area and spatial pattern is still limited due to large changes in agriculture in different regions; for example, higher latitude areas underwent increase (e.g., northeastern China) and decrease (e.g., South Korea) of paddy rice planting areas due to climatic warming, urbanization and other drivers. It is necessary to track paddy rice planting area changes in these regions in the past decades. We developed a pixel- and phenology-based image analysis system, Landsat-RICE, to map the paddy rice by using Landsat imagery. The algorithm was based on the unique physical and spectral characteristics of paddy rice fields during the flooding and transplanting phases. First, Landsat images are preprocessed and time series vegetation indices (NDVI, EVI, and LSWI) are generated. Second, MODIS Land Surface Temperature (LST) data were used to define thermal plant growing season (0 oC, 5 oC and 10 oC), which provides a guide for selection of Landsat images within the period of flooding and transplanting. Third, several non-cropland land cover maps (e.g., permanent water bodies, built-up and barren lands, sparsely vegetated lands, and evergreen vegetation) are produced through analysis of Landsat-based vegetation indices within the plant growing season and combined as a mask. Fourthly, vegetation index data within the time window of flooded and rice transplanting were analyzed to identify flood/transplanting signals. Finally, the maps of paddy rice planting areas were generated through overlying the results from Step 3 and 4. Paddy rice planting area changes were investigated in some hotspots of Northeastern Asia from 1986 to 2014 at 30-m spatial resolution and 5-year interval. This study has demonstrated that our newly developed Landsat-Rice system is robust and effective for tracking paddy rice changes in cold temperate and temperate zones.

Influence of overwintering Tundra Swan against soil nutrients in winter-flooded paddy fields

NASA Astrophysics Data System (ADS)

Somura, H.; Mori, T.

2017-12-01

Over thousands of Tundra Swans visit winter-flooded paddy fields in the study area every year for overwintering from November to March. They roost in the paddy fields during the night and forage in the paddy and surrounding fields during the day since 2004, when farmers began using winter-flooded paddy fields. Before 2004, the swans visited the area for foraging during the day and roosted at nearby lakes, wetlands, and sandbars along rivers during the night. When the swans visited the paddy fields, the water gradually became green and began to emit ammonia odor. In the previous study (Somura et al., 2015), the mean concentrations of nitrogen, phosphorus, suspended sediment, and total organic carbon were higher in the overwintering season than during the irrigation season. TN was mainly present in the form of NH4-N, and its concentrations increased gradually and peaked in January or February. The peak N concentrations coincided with an increase in the number of birds. So bird excrement was thought to have affected the concentrations of N. Further, TP and PO4-P concentrations were influenced by the bird droppings and showed similar trend as those of TN. However, we didn't evaluate influence of the bird feces against soil nutrients at that time. In this study, we conducted soil sampling before and after overwintering and tried to clarify their influences. As a result, it was understood that there was statistically significant differences among the paddy fields before and after overwintering in some elements such as available phosphate and C/N ratio. It means that the bird feces will affect to the nutrient in the paddy soil. However the relationship between the total number of birds in the paddy fields during the period and soil nutrients were unclear yet. Thus further study should be conducted.

Bioremediation of vegetable and agrowastes by Pleurotus ostreatus: a novel strategy to produce edible mushroom with enhanced yield and nutrition.

PubMed

Singh, V K; Singh, M P

2014-12-24

Pleurotus ostreatus was grown on paddy straw as well as other vegetable and agricultural wastes i.e. pea pod shell, cauliflower leaves, radish leaves and brassica straw in various combinations with paddy straw. The mushroom did not grow on the vegetable wastes separately. The cumulative yield and biological efficiency of the edible oyster mushroom P. ostreatus grown on substrate containing paddy straw in various combinations with different vegetable wastes i.e. 20% and 30 % vegetable wastes mixed with 80% and 70% (w/w) of paddy straw was found to be better, when compared with yield and biological efficiency obtained on paddy straw (100%) alone. The protein content and six essential amino acid contents (Leu, Ile, Val, Thr, Met, Phe) showed a significant increase and total sugar and reducing sugar contents showed decrease in the mushroom fruit bodies grown at different combinations of vegetable wastes with paddy straw as compared to paddy straw alone. However, there was not any significant change in moisture content of mushroom cultivated on different groups of wastes. Hence, results of this investigation suggest that the vegetable wastes which are generally left to rot in situ in many cities and villages causing outbreak of diseases can be bioremediated by edible mushroom P. ostreatus. The added advantage is that we get edible mushroom fruit body with improved nutrition.

Simulation on Change Law of Runoff, Sediment and Non-point Source Nitrogen and Phosphorus Discharge under Different Land uses Based on SWAT Model: A Case Study of Er hai Lake Small Watershed

NASA Astrophysics Data System (ADS)

Tong, Xiao Xia; Lai Cui, Yuan; Chen, Man Yu; Hu, Bo; Xu, Wen Sheng

2018-05-01

The Er yuan watershed of Er hai district is chosen as the research area, the law of runoff and sediment and non-point source nitrogen and phosphorus discharges under different land uses during 2001 to 2014 are simulated based on SWAT model. Results of simulation indicate that the order of total runoff yield of different land use type from high to low is grassland, paddy fields, dry land. Specifically, the order of surface runoff yield from high to low is paddy fields, dry land, grassland, the order of lateral runoff yield from high to low is paddy fields, dry land, grassland, the order of groundwater runoff yield from high to low is grassland, paddy fields, dry land. The orders of sediment and nitrogen and phosphorus yield per unit area of different land use type are the same, grassland> paddy fields> dry land. It can be seen, nitrogen and phosphorus discharges from paddy fields and dry land are the main sources of agricultural non-point pollution of the irrigated area. Therefore, reasonable field management measures which can decrease the discharge of nitrogen and phosphorus of paddy fields and dry land are the key to agricultural non-point source pollution prevention and control.

Modelling the fate of pesticides in paddy rice-fish pond farming system in Northern Vietnam

NASA Astrophysics Data System (ADS)

Lamers, M.; Nguyen, N.; Streck, T.

2012-04-01

During the last decade rice production in Vietnam has tremendously increased due to the introduction of new high yield, short duration rice varieties and an increased application of pesticides. Since pesticides are toxic by design, there is a natural concern on the possible impacts of their presence in the environment on human health and environment quality. In North Vietnam, lowland and upland rice fields were identified to be a major non-point source of agrochemical pollution to surface and ground water, which are often directly used for domestic purposes. Field measurements, however, are time consuming, costly and logistical demanding. Hence, quantification, forecast and risk assessment studies are hampered by a limited amount of field data. One potential way to cope with this shortcoming is the use of process-based models. In the present study we developed a model for simulating short-term pesticide dynamics in combined paddy rice field - fish pond farming systems under the specific environmental conditions of south-east Asia. Basic approaches and algorithms to describe the key underlying biogeochemical processes were mainly adopted from the literature to assure that the model reflects the current standard of scientific knowledge and commonly accepted theoretical background. The model was calibrated by means of the Gauss-Marquardt-Levenberg algorithm and validated against measured pesticide concentrations (dimethoate and fenitrothion) during spring and summer rice crop season 2008, respectively, of a paddy field - fish pond system typical for northern Vietnam. First simulation results indicate that our model is capable to simulate the fate of pesticides in such paddy - fish pond farming systems. The model efficiency for the period of calibration, for example, was 0.97 and 0.95 for dimethoate and fenitrothion, respectively. For the period of validation, however, the modeling efficiency slightly decreased to 0.96 and 0.81 for dimethoate and fenitrothion, respectively. In our presentation we will picture key model features and algorithms and demonstrate that our model provides a useful and appropriate tool for analyzing and quantifying the transport and behavior of pesticides in paddy rice farming systems.

More CH4 is emitted during the fallow than during the growing season in a Mediterranean rice agrosystems

NASA Astrophysics Data System (ADS)

Martínez-Eixarch, Maite; Ibàñez, Carles; Alcaraz, Carles; Viñas, Marc; Aranda, Xavier; Saldaña, J. Antonio

2017-04-01

Paddy rice fields are an important source of greenhouse gas emissions (GHG) as they contribute 5 to 20 % of the global anthropogenic CH4 emissions. The Ebre Delta (Catalonia, NE Spain) is one of the most important wetland complexes in the Western Mediterranean with 65 % of its area covered by rice fields. The results herein presented assess the annual pattern of CH4 emissions from paddy rice in Ebre Delta, including the growing and fallow seasons as well as the major environmental variables modulating such emissions. Fifteen rice fields covering the geo-physical variability of the Ebre Delta were selected for GHG monitoring. Common agronomic management was practiced: water direct-seeding, permanent flooding and moderate mineral fertilization during the growing season and straw incorporation, progressive drainage of the fields after the harvest. Fields are left fallow during the winter. GHG were monthly sampled, from May to December in 2015. In each field, three closed chambers were used; from each of these, four gas samples were taken over a 30-minute period. Simultaneously, hydrological regime, soil physic-chemical parameters and plant cover were measured. GHG were analysed by gas chromatography. A Generalized linear model analysis (GLM) was performed to assess the most important influencing factors on CH4 emissions. An information-theoretic approach was used to find the best approximating models. Overall, the CH4 emissions showed a bi-modal pattern, with peaks in July-August and in October. Emissions rates ranged from 2.1 ± 0.5 to 7.5 ± 1.4 mg C-CH4 m-2 h-1 in the growing season (May to September) and from 25.0 ± 5.7 to 20.1 ± 3.3 mg C-CH4 m-2 h-1 at post-harvest (October to December). In total, 314 kg C-CH4 ha-1 were emitted from Ebre Delta rice fields, of which 70 % during post-harvest. Larger off-season emissions were likely induced by straw incorporation. The results of the GLM-IT analysis revealed that during the growing season, soil Eh and water level were the most important factors influencing CH4 emissions, followed by soil temperature and plant cover, with similar degree of importance. During the fallow season, soil redox and water level were also the most important factors, along with air temperature. Throughout the growing and fallow seasons, soil Eh was negatively related to CH4 emissions whereas temperature and plant cover positively. Interestingly, water level showed a contrasting effect on CH4 emissions: positive during the growing season and negative the fallow. Traditionally, most of the research on GHG mitigation options in paddy rice has been focused on the rice growing period and less attention has been paid to the post-harvest season. The higher contribution of the fallow season to the total annual CH4 emissions evidenced in our study suggests that more effort should be made on this season when aiming at mitigating CH4 emissions, being water and straw management the key factors. Accordingly, we also recommend the inclusion of the fallow season for GHG inventories from paddy rice, usually neglected, to avoid CH4 emissions underestimations.

Model development for nutrient loading estimates from paddy rice fields in Korea.

PubMed

Jeon, Ji-Hong; Yoon, Chun G; Ham, Jong-Hwa; Jung, Kwang-Wook

2004-01-01

A field experiment was performed to evaluate water and nutrient balances in paddy rice culture operations during 2001-2002. The water balance analysis indicated that about half (50-60%) of the total outflow was lost by surface drainage, with the remainder occurring by evapotranspiration (490-530 mm). The surface drainage from paddy fields was mainly caused by rainfall and forced-drainage, and in particular, the runoff during early rice culture periods depends more on the forced-drainage due to fertilization practices. Most of the total phosphorus (T-P) inflow was supplied by fertilization at transplanting, while the total nitrogen (T-N) inflow was supplied by the three fertilizations, precipitation. and from the upper paddy field, which comprised 13-33% of the total inflow. Although most of the nutrient outflow was attributed to plant uptake. nutrient loss by surface drainage was substantial, comprising 20% for T-N and 10% for T-P. Water and nutrient balances indicate that reduction of surface drainage from paddy rice fields is imperative for nonpoint source pollution control. The simplified computer model, PADDIMOD, was developed to simulate water and nutrient (T-N and T-P) behavior in the paddy rice field. The model predicts daily ponded water depth, surface drainage, and nutrient concentrations. It was formulated with a few equations and simplified assumptions, but its application and a model fitness test indicated that the simulation results reasonably matched the observed data. It is a simple and convenient planning model that could be used to evaluate BMPs of paddy rice fields alone or in combination with other complex watershed models. Application of the PADDIMOD to other paddy rice fields with different agricultural environments might require further calibration and validation.

Nitrogen and phosphorus effluent loads from a paddy-field district adopting collective crop rotation.

PubMed

Hama, T; Aoki, T; Osuga, K; Sugiyama, S; Iwasaki, D

2012-01-01

Japanese paddy rice systems commonly adopt the rotation of vegetables, wheat and soybeans with paddy rice. Crop rotation may, however, increase the nutrient load in effluent discharged from the district because more fertilizer is applied to the rotation crops than is applied to paddy crops. We investigated a paddy-field district subject to collective crop rotation and quantified the annual nutrient load of effluent from the district in three consecutive years. The total annual exports of nitrogen and phosphorus over the investigation period ranged from 30.3 to 40.6 kg N ha(-1) and 2.62 to 3.13 kg P ha(-1). The results suggest that rotation cropping increases the effluent nutrient load because applied fertilizer is converted to nitrate, and surface runoff is increased due to the absence of shuttering boards at the field outlets.

Effect of water and heat transport processes on methane emissions from paddy soils: a process-based model analysis

NASA Astrophysics Data System (ADS)

Rizzo, Anacleto; Boano, Fulvio; Revelli, Roberto; Ridolfi, Luca

2013-04-01

High CH4 fluxes are emitted from paddy fields worldwide and represent a considerable issue for the rice production eco-sustainability. Water and heat transport fluxes are known to strongly influence biogeochemical cycles in wetland environments, and therefore also CH4 emissions from paddy soils. Water percolation affects the dynamics of many compounds (e.g. DOC, O2) influencing CH4 fate. On the other hand, heat fluxes strongly influence CH4 production in submerged rice crops, and lowering ponding water temperature (LPWT) can reduce microbial activities and consequently decrease CH4 emissions. Moreover, as long as the optimal temperature range for rice growth is maintained, LPWT can lower CH4 emissions without rice yield limitation. Hence, a process-based model is proposed and applied to investigate the role of water flow on CH4 emissions, and to analyse the efficiency of LPWT as mitigation strategy for CH4 production and release. The process-based model relies on a system of partial differential mass balance equations to describe the vertical dynamics of the chemical compounds leading to CH4 production. Many physico-chemical processes and features characteristic of paddy soil are included: paddy soil stratigraphy; spatio-temporal variations of plant-root compartment; water and heat transport; SOC decomposition; heterotrophic reactions in both aerobic and anaerobic conditions; root radial oxygen loss; root solute uptake; DOC root exudation; plant-mediated, ebullition, and diffusion gas exchange pathways. LPWT is included as a temperature shift subtracted directly to the ponding water temperature. Model results confirm the importance of water flow on CH4 emission, since simulations that do not include water fluxes show a considerable overestimation of CH4 emissions due to a different DOC spatio-temporal dynamics. Particularly, when water fluxes are not modeled the overestimation can reach 67 % of the total CH4 emission over the whole growing season. Moreover, model results also suggest that roots influence CH4 dynamics principally due to their solute uptake, while root effect on advective flow plays a minor role. In addition, the analysis of CH4 transport fluxes show the limiting effect of upward dispersive transport fluxes on the downward CH4 percolation. Finally, LPWT is confirmed to be a valid mitigation strategy for CH4 emissions from paddy soils, since the reduction of CH4 emission reach about -50 % with a LPWT equal to only 2°C over the whole growing season.

Water-saving ground cover rice production system reduces net greenhouse gas fluxes in an annual rice-based cropping system

NASA Astrophysics Data System (ADS)

Yao, Z.; Du, Y.; Tao, Y.; Zheng, X.; Liu, C.; Lin, S.; Butterbach-Bahl, K.

2014-11-01

To safeguard food security and preserve precious water resources, the technology of water-saving ground cover rice production system (GCRPS) is being increasingly adopted for rice cultivation. However, changes in soil water status and temperature under GCRPS may affect soil biogeochemical processes that control the biosphere-atmosphere exchanges of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2). The overall goal of this study is to better understand how net ecosystem greenhouse gas exchanges (NEGE) and grain yields are affected by GCRPS in an annual rice-based cropping system. Our evaluation was based on measurements of the CH4 and N2O fluxes and soil heterotrophic respiration (CO2 emissions) over a complete year, and the estimated soil carbon sequestration intensity for six different fertilizer treatments for conventional paddy and GCRPS. The fertilizer treatments included urea application and no N fertilization for both conventional paddy (CUN and CNN) and GCRPS (GUN and GNN), and solely chicken manure (GCM) and combined urea and chicken manure applications (GUM) for GCRPS. Averaging across all the fertilizer treatments, GCRPS increased annual N2O emission and grain yield by 40 and 9%, respectively, and decreased annual CH4 emission by 69%, while GCRPS did not affect soil CO2 emissions relative to the conventional paddy. The annual direct emission factors of N2O were 4.01, 0.09 and 0.50% for GUN, GCM and GUM, respectively, and 1.52% for the conventional paddy (CUN). The annual soil carbon sequestration intensity under GCRPS was estimated to be an average of -1.33 Mg C ha-1 yr-1, which is approximately 44% higher than the conventional paddy. The annual NEGE were 10.80-11.02 Mg CO2-eq ha-1 yr-1 for the conventional paddy and 3.05-9.37 Mg CO2-eq ha-1 yr-1 for the GCRPS, suggesting the potential feasibility of GCRPS in reducing net greenhouse effects from rice cultivation. Using organic fertilizers for GCRPS considerably reduced annual emissions of CH4 and N2O and increased soil carbon sequestration, resulting in the lowest NEGE (3.05-5.00 Mg CO2-eq ha-1 yr-1). Accordingly, water-saving GCRPS with organic fertilizer amendments was considered the most promising management regime for simultaneously achieving relatively high grain yield and reduced net greenhouse gas emission.

Water-saving ground cover rice production system reduces net greenhouse gas fluxes in an annual rice-based cropping system

NASA Astrophysics Data System (ADS)

Yao, Z.; Du, Y.; Tao, Y.; Zheng, X.; Liu, C.; Lin, S.; Butterbach-Bahl, K.

2014-06-01

To safeguard food security and preserve precious water resources, the technology of water-saving ground cover rice production system (GCRPS) is being increasingly adopted for the rice cultivation. However, changes in soil water status and temperature under GCRPS may affect soil biogeochemical processes that control the biosphere-atmosphere exchanges of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2). The overall goal of this study is to better understand how net ecosystem greenhouse gas exchanges (NEGE) and grain yields are affected by GCRPS in an annual rice-based cropping system. Our evaluation was based on measurements of the CH4 and N2O fluxes and soil heterotrophic respiration (CO2 emission) over a complete year, as well as the estimated soil carbon sequestration intensity for six different fertilizer treatments for conventional paddy and GCRPS. The fertilizer treatments included urea application and no N fertilization for both conventional paddy (CUN and CNN) and GCRPS (GUN and GNN), solely chicken manure (GCM) and combined urea and chicken manure applications (GUM) for GCRPS. Averaging across all the fertilizer treatments, GCRPS increased annual N2O emission and grain yield by 40% and 9%, respectively, and decreased annual CH4 emission by 69%, while GCRPS did not affect soil CO2 emissions relative to the conventional paddy. The annual direct emission factors of N2O were 4.01, 0.087 and 0.50% for GUN, GCM and GUM, respectively, and 1.52% for the conventional paddy (CUN). The annual soil carbon sequestration intensity under GCRPS was estimated to be an average of -1.33 Mg C ha-1 yr-1, which is approximately 44% higher than the conventional paddy. The annual NEGE were 10.80-11.02 Mg CO2-eq ha-1 yr-1 for the conventional paddy and 3.05-9.37 Mg CO2-eq ha-1 yr-1 for the GCRPS, suggesting the potential feasibility of GCRPS in reducing net greenhouse effect from rice cultivation. Using organic fertilizers for GCRPS considerably reduced annual emissions of CH4 and N2O and increased soil carbon sequestration, resulting in the lowest NEGE (3.05-5.00 Mg CO2-eq ha-1 yr-1). Accordingly, water-saving GCRPS with organic fertilizer amendments was considered the most promising management regime for simultaneously achieving relatively high grain yield and reduced net greenhouse gas emission.

Rodent Depredation -- A Direct Seeding Problem

Treesearch

O. Gordon Langdon; William P. LeGrande

1965-01-01

Foresters have known for a long time that seed-eating rodents, birds, and insects must be circumvented before direct seeding can be successful. Advances have been made in reducing losses in the direct seeding of pine by the use of chemical repellents, and in several areas of the South recommended concentrations have been satisfactory. Direct seeding is now on an...

Similarities in chemical composition of soil organic matter across a millennia-old paddy soil chronosequence as revealed by advanced solid-state NMR spectroscopy

USDA-ARS?s Scientific Manuscript database

Soil organic matter (SOM) accumulation in paddy soils has aroused considerable attention due to its vital significance in global food, energy, climate, and environmental issues. Considerable progress has been made toward the understanding of changes in the quantity of SOM in paddy soils over a mille...

[Characteristics of paddy field nitrogen leakage and runoff in rice-duck farming system].

PubMed

Yu, Xiang; Wang, Qiang-sheng; Wang, Shao-hua; Liu, Zheng-hui; Wang, Xia-wen; Ding, Yan-feng

2009-01-01

A field experiment was conducted to study the characteristics of paddy field nitrogen (N) leakage and runoff under rice-duck farming (MRD), conventional farming (MR), and conventional farming with flooding (CK). Comparing with that under MR, the paddy field under MRD had a notable decrease of N (especially NO3- -N) concentration in its leaked liquid; but this concentration was tended to be increased, compared with that under CK. After 7-9 days of fertilization, the NH4+ -N and NO3- -N concentrations in paddy field surface water were higher under MRD than under MR. However, owing to the no draining and the higher band, the paddy field under MRD had a notable reduction of drainage, resulting in a marked decrease of N runoff than that under MR. Comparing with MR, the paddy field under MRD had an addition of nitrogen supply from duck dung, a reduction of N leakage and runoff, a lesser application of chemical nitrogen fertilizer, and more nitrogen uptake by rice plant. Both the reduction of N input and that of N output in rice-duck farming system were nearly equal in quantity.

Understanding the ecological background of rice agriculture on the Ningshao Plain during the Neolithic Age: pollen evidence from a buried paddy field at the Tianluoshan cultural site

NASA Astrophysics Data System (ADS)

Li, Chunhai; Zheng, Yunfei; Yu, Shiyong; Li, Yongxiang; Shen, Huadong

2012-03-01

The progressive rise of atmospheric CH4 level since 5 ka has been hypothesized to result from human agricultural activities that turned forested lands, which would otherwise be a carbon sink, into paddy fields. Increasing numbers of Neolithic cultural sites unearthed in coastal eastern China, providing unique opportunities to test this hypothesis. Here, we present detailed pollen data from a buried paddy field at Tianluoshan cultural site on the Ningshao Plain, eastern China, to reconstruct the ecological conditions associated with the establishment of paddy fields. Stratigraphic data, radiocarbon ages, and pollen analyses show that vegetation underwent six phases of evolution and paddy fields were developed from 7000 to 4200 cal. yr BP. We found no evidence of slash-and-burn agriculture at the study site. Together with no presence of the irrigation system, our pollen data suggest the paddy fields at this site originated from wetlands. Hence, our findings do not support the hypothesis that anthropogenic-induced deforestation play ed a significant role in the rise of the atmospheric CH4 rise since the middle Holocene.

Measuring and modeling the temporal dynamics of nitrogen balance in an experimental-scale paddy field

NASA Astrophysics Data System (ADS)

Tseng, C.; Lin, Y.

2013-12-01

Nitrogen balance involves many mechanisms and plays an important role to maintain the function of nature. Fertilizer application in agriculture activity is usually seen as a common and significant nitrogen input to environment. Improper fertilizer application on paddy field can result in great amount of various types of nitrogen losses. Hence, it is essential to understand and quantify the nitrogen dynamics in paddy field for fertilizer management and pollution control. In this study, we develop a model which considers major transformation processes of nitrogen (e.g. volatilization, nitrification, denitrification and plant uptake). In addition, we measured different types of nitrogen in plants, soil and water at plant growth stages in an experimental-scale paddy field in Taiwan. The measurement includes total nitrogen in plants and soil, and ammonium-N (NH4+-N), nitrate-N (NO3--N) and organic nitrogen in water. The measured data were used to calibrate the model parameters and validate the model for nitrogen balance simulation. The results showed that the model can accurately estimate the temporal dynamics of nitrogen balance in paddy field during the whole growth stage. This model might be helpful and useful for future fertilizer management and pollution control in paddy field.

Mitigating methane emission from paddy soil with rice-straw biochar amendment under projected climate change

PubMed Central

Han, Xingguo; Sun, Xue; Wang, Cheng; Wu, Mengxiong; Dong, Da; Zhong, Ting; Thies, Janice E.; Wu, Weixiang

2016-01-01

Elevated global temperatures and increased concentrations of carbon dioxide (CO2) in the atmosphere associated with climate change will exert profound effects on rice cropping systems, particularly on their greenhouse gas emitting potential. Incorporating biochar into paddy soil has been shown previously to reduce methane (CH4) emission from paddy rice under ambient temperature and CO2. We examined the ability of rice straw-derived biochar to reduce CH4 emission from paddy soil under elevated temperature and CO2 concentrations expected in the future. Adding biochar to paddy soil reduced CH4 emission under ambient conditions and significantly reduced emissions by 39.5% (ranging from 185.4 mg kg−1 dry weight soil, dws season−1 to 112.2 mg kg−1 dws season−1) under simultaneously elevated temperature and CO2. Reduced CH4 release was mainly attributable to the decreased activity of methanogens along with the increased CH4 oxidation activity and pmoA gene abundance of methanotrophs. Our findings highlight the valuable services of biochar amendment for CH4 control from paddy soil in a future that will be shaped by climate change. PMID:27090814

Phylogenetic Distribution of the Capsid Assembly Protein Gene (g20) of Cyanophages in Paddy Floodwaters in Northeast China

PubMed Central

Jing, Ruiyong; Liu, Junjie; Yu, Zhenhua; Liu, Xiaobing; Wang, Guanghua

2014-01-01

Numerous studies have revealed the high diversity of cyanophages in marine and freshwater environments, but little is currently known about the diversity of cyanophages in paddy fields, particularly in Northeast (NE) China. To elucidate the genetic diversity of cyanophages in paddy floodwaters in NE China, viral capsid assembly protein gene (g20) sequences from five floodwater samples were amplified with the primers CPS1 and CPS8. Denaturing gradient gel electrophoresis (DGGE) was applied to distinguish different g20 clones. In total, 54 clones differing in g20 nucleotide sequences were obtained in this study. Phylogenetic analysis showed that the distribution of g20 sequences in this study was different from that in Japanese paddy fields, and all the sequences were grouped into Clusters α, β, γ and ε. Within Clusters α and β, three new small clusters (PFW-VII∼-IX) were identified. UniFrac analysis of g20 clone assemblages demonstrated that the community compositions of cyanophage varied among marine, lake and paddy field environments. In paddy floodwater, community compositions of cyanophage were also different between NE China and Japan. PMID:24533125

Sequestration of organic nitrogen in a paddy soil chronosequence as assessed by amino sugars molecular markers

NASA Astrophysics Data System (ADS)

Roth, Philipp; Lehndorff, E.; Cao, Z.; Amelung, W.

2010-05-01

Available nitrogen is a limiting factor in paddy rice systems due to ammonia volatilization, denitrification and stabilization in organic complexes. Soil organic nitrogen (SON) might therefore constitute a critical component of the nitrogen cycle in rice systems. The objective of this study was to elucidate the role of microorganisms for the sequestration of paddy N in organic forms. For this purpose we analyzed amino sugars as markers for the residues of bacteria and fungi in a chronosequence of soils that were used for paddy rice production for a period of 0 to 2000 years in the Hangzhou bay area in Southeast China. Within the soil profile, amino sugar concentrations were generally highest in the puddled Ap horizon and decreased with increasing depth along with organic carbon concentrations regardless of the time of rice cultivation. Nevertheless, a sharp increase of total amino sugar concentration from 0.1 g kg-1 to 0.3 g kg-1 was observed in the Ah horizon when comparing tidal wetland to salt marsh that had been impoldered 30 years ago, indicating an increasing importance of microbial residues in SON stabilization following the conversion of the semiaquatic marsh to a terrestrial system. With increased time of paddy rice cropping, amino sugar concentrations continued to increase up to a maximum of 2.1 g kg-1 after 300 years of paddy cultivation but declined again to 1 g kg-1 in soils with 700-2000 years history of cultivation despite increasing organic matter accumulation. Changes in the composition of the amino sugars were also most pronounced at initial stages of paddy rice management. The proportions of glucosamine (abundant in fungal chitin) decreased during the first 50 years of cultivation relative to mainly galactosamine (abundant in bacterial gums) and muramic acid (abundant in bacterial peptidoglycan), that remained at constantly low levels. At later stages of paddy rice cultivation, the ratios of glucosamine to galactosamine and to muramic acid re-increased. We conclude that microorganisms significantly contribute to the sequestration of paddy N in organic forms during the first 300 years of cropping, within an increasing contribution of bacteria as cropping time proceeds. At even longer periods of paddy rice cultivation, there appears to be a backshift to lower concentrations of microbial residues with higher proportions of fungal N remaining.

Influence of bird feces to water quality in paddy fields during winter season

NASA Astrophysics Data System (ADS)

Somura, H.; Takeda, I.; Masunaga, T.; Mori, Y.; Ide, J.

2009-12-01

Thousands of migratory birds such as tundra swan came to the paddy fields for overwintering in recent years in the study area. They stayed in paddy fields during night time for sleeping and used around the fields as a feeding ground during day time. During the birds stay, it was observed that water pooled in the paddy fields gradually turned green and gave off a bad smell. In this study, we tried to estimate the influence of the bird’s feces to water quality in the paddy fields. The study area is in the southeastern portion of Matsue City in Shimane Prefecture, Japan. In several paddy fields, puddling procedure was executed after harvesting rice and then water was stored in the paddy fields during winter season. This is because of being easier of farming activities such as weeding next season and of avoiding using pesticide for weeding with rising of environmental awareness. Water in the paddy fields was collected once or twice a month from the target fields and analyzed nitrogen, phosphorus, and organic carbon in 2007. In the study in 2006, as water was sampled once a week and the changes in the water quality had been grasped, we paid attention to behavior of the birds in a day in the field investigation in 2007. The number of the birds was counted once an hour from visible 7 am to 6 pm once a month. In addition to this, fresh feces were sampled from the fields and analyzed the contents of nitrogen, phosphorus, and organic carbon in the feces. As results, average water qualities of TN, TP, and TOC from November 2007 to March 2008 showed very high concentrations compared with a river water concentration used as irrigation water. More than 70% of TN in the water was ammonia nitrogen. Moreover, comparing with a standard fertilizer amount of nitrogen and phosphorus for paddy fields during irrigation period, it was estimated that the amount of nitrogen excreted by the bird’s feces during the winter season was equivalent to the standard fertilizer amount and the amount of phosphorus was about 30% of the standard amount. From these results, it was concluded that feces and urine from the birds influenced a lot to the water quality in the paddy fields.

Wetland biomass crops: Studies in natural and managed stands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, N.J.

1989-01-01

Wetlands dominated by Typha spp. and other emergent macrophytes are some of the most productive natural systems in the temperate zone. The subject of this thesis is the selection and management of potential emergent biomass crops and is presented in the following three chapters: (1) The Productivity of Typha spp. in Managed Stands in Minnesota, (II) The Establishment of Typha spp. on a Northern Minnesota Peatland, and (III) Wetland Species Yield Comparisons. Typha rhizomes were planted in a series of 1.5 m{sup 2} paddies. Variables investigated included planting density, fertilizer application rate and seasonal changes in above and below-ground biomass,more » shoot height and density. Yield increased with increased planting density. Maximum shoot dry weight occurred in August while maximum below ground dry weight was obtained in October. Trial plots were established on a northern Minnesota peatland using both rhizomes and seed. The influence of planting density, substrate preparation and fertilizer application on the seasonal development and productivity of trial plots was investigated. Through extensive literature surveys and sampling natural stands, five species were identified for further screening including: Carex atherodes, Phragmites australis, Scirpus fluviatilis, Sparganium eurycarpum and Spartina pectinata. These species, along with planting stock from five productive Typha stands were planted in 1.5 m{sup 2} paddies to compare productivity and growth characteristics under identical conditions. Trial plots of Phragmites, Scirpus and Sparganium were also established on excavated peatland plots.« less

Evaluation of weed control efficacy and crop safety of the new HPPD-inhibiting herbicide-QYR301.

PubMed

Wang, Hengzhi; Liu, Weitang; Zhao, Kongping; Yu, Hui; Zhang, Jia; Wang, Jinxin

2018-05-21

QYR301, 1,3-Dimethyl-1H-pyrazole-4-carboxylic acid 4-[2-chloro-3-(3,5-dimethyl-pyrazol-1-ylmethyl)-4-methanesulfonyl-benzoyl]-2,5-dimethyl-2H-pyrazol-3-yl ester, is a novel HPPD-inhibiting herbicide and was evaluated to provide a reference for post-emergence (POST) application under greenhouse and field conditions. The crop safety (180 and 360 g active ingredient (a.i.) ha -1 treatments) experiment revealed that wheat, paddy, garlic and corn were the only four crops without injury at both examined herbicide rates. The weed control efficacy (60 and 120 g a.i. ha -1 ) experiment showed that QYR301 exhibited high efficacy against many weeds, especially weeds infesting paddy fields. Furthermore, it is interesting that both susceptible and multiple herbicide resistant Echinochloa crus-galli (L.) Beauv. and Echinochloa phyllopogon (Stapf) Koss, two notorious weed species in paddy field, remained susceptible to QYR301. Further crop tolerance results indicated that 20 tested paddy hybrids displayed different levels of tolerance to QYR301, with the japonica paddy hybrids having more tolerance than indica paddy hybrids under greenhouse conditions. Results obtained from field experiments showed that QYR301 POST at 135 to 180 g a.i. ha -1 was recommended to provide satisfactory full-season control of E. crus-galli and Leptochloa chinensis (L.) Nees and to maximize rice yields. These findings indicate that QYR301 possesses great potential for the management of weeds in paddy fields.

Seasonal variation of carbon dioxide and methane exchange between rice paddy fields and atmosphere in Japan

NASA Astrophysics Data System (ADS)

Kokubo, R.

2017-12-01

Rice paddy fields spread throughout Asia and play an important role in terms of regulating greenhouse gases on the ground. Rice paddies have the potential to either increase or decrease the net balance of greenhouse gases in the atmosphere. In the rice growth period, rice paddy fields are sources of CH4, whereas they generally act as a sink of CO2. However, the behavior of greenhouse gases during fallow periods has not been well understood. A field experiment was conducted at a rice paddy field in Fuchu, central Japan in 2014. We evaluated CO2 and CH4 fluxes in the rice paddy field using the eddy covariance method. Except for 20 days after transplanting (DAT), temporal CO2 fluxes showed negative values during a rice growth period whereas they showed positive values throughout a fallow period. The positive CO2 fluxes at 2 emissions by respiration of rice plants and soil microorganisms than CO2 uptake by photosynthesis of rice plants. In the middle of the growing season at around DAT=50, CO2 emission became dominant again because flooded water was temporarily drained in the rice paddy field. Seasonal CH4 fluxes during a growth period were regulated by water management and plant growth stages. During a fallow period, however, the field was kept a non-flooded condition that resulted in an aerobic soil condition and thus very low CH4 emission.

Sources of nitrous and nitric oxides in paddy soils: nitrification and denitrification.

PubMed

Lan, Ting; Han, Yong; Roelcke, Marco; Nieder, Rolf; Car, Zucong

2014-03-01

Rice-paddies are regarded as one of the main agricultural sources of N 2O and NO emissions. To date, however, specific N2O and NO production pathways are poorly understood in paddy soils. (15)N-tracing experiments were carried out to investigate the processes responsible for N2O and NO production in two paddy soils with substantially different soil properties. Laboratory incubation experiments were carried out under aerobic conditions at moisture contents corresponding to 60% of water holding capacity. The relative importance of nitrification and denitrification to the flux of N2O was quantified by periodically measuring and comparing the enrichments of the N2O, NH(+)4-N and NO(-)3-N pools. The results showed that both N2O and NO emission rates in an alkaline paddy soil with clayey texture were substantially higher than those in a neutral paddy soil with silty loamy texture. In accordance with most published results, the ammonium N pool was the main source of N2O emission across the soil profiles of the two paddy soils, being responsible for 59.7% to 97.7% of total N2O emissions. The NO(-)3-N pool of N2O emission was relatively less important under the given aerobic conditions. The rates of N2O emission from nitrification (N2On) among different soil layers were significantly different, which could be attributed to both the differences in gross N nitrification rates and to the ratios of nitrified N emitted as N2O among soil layers. Furthermore, NO fluxes were positively correlated with the changes in gross nitrification rates and the ratios of NO/N2O in the two paddy soils were always greater than one (from 1.26 to 6.47). We therefore deduce that, similar to N2O, nitrification was also the dominant source of NO in the tested paddy soils at water contents below 60% water holding capacity. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Distribution of tetraether lipids in agricultural soils - differentiation between paddy and upland management

NASA Astrophysics Data System (ADS)

Mueller-Niggemann, Cornelia; Rahayu Utami, Sri; Marxen, Anika; Mangelsdorf, Kai; Bauersachs, Thorsten; Schwark, Lorenz

2016-03-01

Rice paddies constitute almost a fifth of global cropland and provide more than half of the world's population with staple food. At the same time, they are a major source of methane and therewith significantly contribute to the current warming of Earth's atmosphere. Despite their apparent importance in the cycling of carbon and other elements, however, the microorganisms thriving in rice paddies are insufficiently characterized with respect to their biomolecules. Hardly any information exists on human-induced alteration of biomolecules from natural microbial communities in paddy soils through varying management types (affecting, e.g., soil or water redox conditions, cultivated plants). Here, we determined the influence of different land use types on the distribution of glycerol dialkyl glycerol tetraethers (GDGTs), which serve as molecular indicators for microbial community structures, in rice paddy (periodically flooded) and adjacent upland (non-flooded) soils and, for further comparison, forest, bushland and marsh soils. To differentiate local effects on GDGT distribution patterns, we collected soil samples in locations from tropical (Indonesia, Vietnam and Philippines) and subtropical (China and Italy) sites. We found that differences in the distribution of isoprenoid GDGTs (iGDGTs) as well as of branched GDGTs (brGDGTs) are predominantly controlled by management type and only secondarily by climatic exposition. In general, upland soil had higher crenarchaeol contents than paddy soil, which by contrast was more enriched in GDGT-0. The GDGT-0 / crenarchaeol ratio, indicating the enhanced presence of methanogenic archaea, was 3-27 times higher in paddy soils compared to other soils and increased with the number of rice cultivation cycles per year. The index of tetraethers consisting of 86 carbons (TEX86) values were 1.3 times higher in upland, bushland and forest soils than in paddy soils, potentially due to differences in soil temperature. In all soils brGDGT predominated over iGDGTs with the relative abundance of brGDGTs increasing from subtropical to tropical soils. Higher branched vs. isoprenoid tetraether (BIT) values in paddy soils compared to upland soils together with higher BIT values in soils from subtropical climates indicated effects on the amounts of brGDGT induced by differences in management as well as climate. In acidic soils cyclization ratio of branched tetraethers (CBT) values correlated well with soil pH. In neutral to alkaline soils, however, no correlation but an offset in CBT between paddy and upland managed soils was detected. This is interpreted as indicating soil moisture exerting an additional control on the CBT in these soils. Lower modified methylation index of branched tetraether (MBT') values and temperatures calculated from this (TMC) in paddy soils compared to upland soils are attributed to a management-induced (e.g. enhanced soil moisture via flooding) effect on mean annual soil temperature (MST).

Soil quality assessment in long-term direct seed

USDA-ARS?s Scientific Manuscript database

Producers in the Pacific Northwest are adopting direct seed farming to reduce soil erosion, improve soil quality and increase water infiltration. Some direct seed producers are concerned with reaching the yield and profit potential expected with long-term direct seed, and this may be due to soil st...

Comparative Transcriptomic Analysis in Paddy Rice under Storage and Identification of Differentially Regulated Genes in Response to High Temperature and Humidity.

PubMed

Zhao, Chanjuan; Xie, Junqi; Li, Li; Cao, Chongjiang

2017-09-20

The transcriptomes of paddy rice in response to high temperature and humidity were studied using a high-throughput RNA sequencing approach. Effects of high temperature and humidity on the sucrose and starch contents and α/β-amylase activity were also investigated. Results showed that 6876 differentially expressed genes (DEGs) were identified in paddy rice under high temperature and humidity storage. Importantly, 12 DEGs that were downregulated fell into the "starch and sucrose pathway". The quantitative real-time polymerase chain reaction assays indicated that expression of these 12 DEGs was significantly decreased, which was in parallel with the reduced level of enzyme activities and the contents of sucrose and starch in paddy rice stored at high temperature and humidity conditions compared to the control group. Taken together, high temperature and humidity influence the quality of paddy rice at least partially by downregulating the expression of genes encoding sucrose transferases and hydrolases, which might result in the decrease of starch and sucrose contents.

Spatial Analysis to Determine Paddy Field Changes in Indonesia: A Case Study in Suburban Areas of Jakarta

NASA Astrophysics Data System (ADS)

Putri Utami, Nadia; Ahamed, Tofael

2018-05-01

Karawang, a suburban area of Greater Jakarta, is known as the second largest rice-producing region in West Java, Indonesia. However, expansion of urban sprawl and industrial area from Greater Jakarta have created rapid agricultural land use/cover changes, especially paddy field, in Karawang. This study analyzed the land use/cover changes of paddy field from 2000 to 2016. Landsat 4-5 TM and Landsat 8 OLI/TIRS images were acquired from USGS Earth Explorer, UTM zone 48 south. Satellite image pre-processing, ground truth data collection, supervised maximum likelihood classifications, and Post-Classification Comparison (PCC) were performed in ArcGIS 10.3®. It was observed between 2000 and 2016, urban area increased 4.46% (8530 ha) from initial area of 10,004 ha. Meanwhile paddy field decreased 3.18% (6091 ha) from initial area of 115,720 ha. The spatial analysis showed that paddy field in the fringe of urban area are more susceptible for changes.

Evaluation of thermophilic fungal consortium for paddy straw composting.

PubMed

Kumar, Adesh; Gaind, Sunita; Nain, Lata

2008-06-01

Out of 10 thermophilic fungi isolated from wheat straw, farm yard manure, and soil, only three showed highest cellobiase, carboxymethyl cellulase, xylanase, and FPase activities. They were identified as Aspergillus nidulans (Th(4)), Scytalidium thermophilum (Th(5)), and Humicola sp. (Th(10)). A fungal consortium of these three fungi was used to compost a mixture (1:1) of silica rich paddy straw and lignin rich soybean trash. The composting of paddy straw for 3 months, during summer period in North India, resulted in a product with C:N ratio 9.5:1, available phosphorus 0.042% and fungal biomass 6.512 mg of N-acetyl glucosamine/100 mg of compost. However, a C:N ratio of 10.2:1 and highest humus content of 3.3% was achieved with 1:1 mixture of paddy straw and soybean trash. The fungal consortium was effective in converting high silica paddy straw into nutritionally rich compost thereby leading to economical and environment friendly disposal of this crop residue.

Ammonia Volatilization Losses from Paddy Fields under Controlled Irrigation with Different Drainage Treatments

PubMed Central

He, Yupu; Yang, Shihong; Wang, Yijiang

2014-01-01

The effect of controlled drainage (CD) on ammonia volatilization (AV) losses from paddy fields under controlled irrigation (CI) was investigated by managing water table control levels using a lysimeter. Three drainage treatments were implemented, namely, controlled water table depth 1 (CWT1), controlled water table depth 2 (CWT2), and controlled water table depth 3 (CWT3). As the water table control levels increased, irrigation water volumes in the CI paddy fields decreased. AV losses from paddy fields reduced due to the increases in water table control levels. Seasonal AV losses from CWT1, CWT2, and CWT3 were 59.8, 56.7, and 53.0 kg N ha−1, respectively. AV losses from CWT3 were 13.1% and 8.4% lower than those from CWT1 and CWT2, respectively. A significant difference in the seasonal AV losses was confirmed between CWT1 and CWT3. Less weekly AV losses followed by TF and PF were also observed as the water table control levels increased. The application of CD by increasing water table control levels to a suitable level could effectively reduce irrigation water volumes and AV losses from CI paddy fields. The combination of CI and CD may be a feasible water management method of reducing AV losses from paddy fields. PMID:24741349

Effect of land use pattern change from paddy soil to vegetable soil on the adsorption-desorption of cadmium by soil aggregates.

PubMed

Zhang, Qiu; Li, Zhongwu; Huang, Bin; Luo, Ninglin; Long, Lingzhi; Huang, Mei; Zhai, Xiuqing; Zeng, Guangming

2017-01-01

The influence of land use change from paddy soil to vegetable soil on the adsorption-desorption behavior of Cd in soil aggregates and the variation in soil properties were investigated. The vegetable soil was characterized by lower pH, organic matter content, cation exchange capacity (CEC), free iron oxides, manganese oxides, and catalase activity and higher urease activity compared with the paddy soil. In the isothermal adsorption and desorption experiments, the adsorption characteristics of Cd of the two soils could be well described by Langmuir and Freundlich equations. The adsorption capacity of vegetable soil decreased 22.72 %, and the desorption rate increased 35 % with respect to paddy soil. Therefore, conversion from paddy to vegetable field can reduce the adsorption ability to Cd of the soil to a certain extent. Both the two soils reached the maximum adsorption capacity and the minimum desorption rate in the <0.002-mm faction. The adsorption capacity of Cd in paddy and vegetable soils exhibited great reliance on the content of CEC. Desorption rate was negatively correlated with the four indicators: organic matter, CEC, free iron oxides, and manganese oxides, and specific adsorption was primarily controlled by soil organic matter and manganese oxides.

Ammonia volatilization losses from paddy fields under controlled irrigation with different drainage treatments.

PubMed

He, Yupu; Yang, Shihong; Xu, Junzeng; Wang, Yijiang; Peng, Shizhang

2014-01-01

The effect of controlled drainage (CD) on ammonia volatilization (AV) losses from paddy fields under controlled irrigation (CI) was investigated by managing water table control levels using a lysimeter. Three drainage treatments were implemented, namely, controlled water table depth 1 (CWT1), controlled water table depth 2 (CWT2), and controlled water table depth 3 (CWT3). As the water table control levels increased, irrigation water volumes in the CI paddy fields decreased. AV losses from paddy fields reduced due to the increases in water table control levels. Seasonal AV losses from CWT1, CWT2, and CWT3 were 59.8, 56.7, and 53.0 kg N ha(-1), respectively. AV losses from CWT3 were 13.1% and 8.4% lower than those from CWT1 and CWT2, respectively. A significant difference in the seasonal AV losses was confirmed between CWT1 and CWT3. Less weekly AV losses followed by TF and PF were also observed as the water table control levels increased. The application of CD by increasing water table control levels to a suitable level could effectively reduce irrigation water volumes and AV losses from CI paddy fields. The combination of CI and CD may be a feasible water management method of reducing AV losses from paddy fields.

Nondestructive evaluation of Bakwan paddy grains moisture content by means of spectrophotometry

NASA Astrophysics Data System (ADS)

Makky, M.; Putry, R. E.; Nakano, K.; Santosa

2018-03-01

Paddy grains moisture content (MC) strongly correlated to the physical properties of rice after being milled. Incorrect MC will cause higher percentage of broken rice and prompts the grains to be more fragile. In general, paddy grains with 13 – 14% MC are ideal for post-harvest processing. The objective of this study is to measure the MC of intact paddy grain from CV. Bakwan by means of non-destructive evaluation using NIR spectral assessment. Paddy grains samples with identical MC were put into 30 mm tube glass and measured using NIR spectrophotometer. The electromagnetic radiation absorbance under consideration upon spectral measurement fell between 1000 and 2500 nm. The grains’ actual MC was then measured by primary method, based on weight measurement i.e. oven method. In this study, the spectral data of the grains was then processed by means of Principal Component Analysis (PCA) before correlated with its MCs by Partial Least Square (PLS) method. The model calibration obtained correlation (r) of 0.983 and RMSEC of 1.684. Moreover, model validation produced correlation (r) of 0.973, RMSEP of 2.095, and bias of 0.2, indicating that the MC of paddy grains can be precisely identified by non-destructive evaluation using spectral analysis.

[Response of mineralization of dissolved organic carbon to soil moisture in paddy and upland soils in hilly red soil region].

PubMed

Chen, Xiang-Bi; Wang, Ai-Hua; Hu, Le-Ning; Huang, Yuan; Li, Yang; He, Xun-Yang; Su, Yi-Rong

2014-03-01

Typical paddy and upland soils were collected from a hilly subtropical red-soil region. 14C-labeled dissolved organic carbon (14C-DOC) was extracted from the paddy and upland soils incorporated with 14C-labeled straw after a 30-day (d) incubation period under simulated field conditions. A 100-d incubation experiment (25 degrees C) with the addition of 14C-DOC to paddy and upland soils was conducted to monitor the dynamics of 14C-DOC mineralization under different soil moisture conditions [45%, 60%, 75%, 90%, and 105% of the field water holding capacity (WHC)]. The results showed that after 100 days, 28.7%-61.4% of the labeled DOC in the two types of soils was mineralized to CO2. The mineralization rates of DOC in the paddy soils were significantly higher than in the upland soils under all soil moisture conditions, owing to the less complex composition of DOC in the paddy soils. The aerobic condition was beneficial for DOC mineralization in both soils, and the anaerobic condition was beneficial for DOC accumulation. The biodegradability and the proportion of the labile fraction of the added DOC increased with the increase of soil moisture (45% -90% WHC). Within 100 days, the labile DOC fraction accounted for 80.5%-91.1% (paddy soil) and 66.3%-72.4% (upland soil) of the cumulative mineralization of DOC, implying that the biodegradation rate of DOC was controlled by the percentage of labile DOC fraction.

Socio-economic impacts of irrigated agriculture in Mbarali District of south west Tanzania

NASA Astrophysics Data System (ADS)

Mwakalila, Shadrack

Irrigation has been found to be central in curbing food scarcity not only in Tanzania but also in many other developing countries. It has been proved that continued reliability on rainfall in agriculture cannot sustain the increase in population. This study examines the impacts of smallholder irrigated agriculture in improving social and economic benefits in Igurusi Ward of Mbarali District which is located in the southern-western part of Tanzania. The study applies the Participatory Rural Appraisal Framework for data collection. The study was confined to five villages in Igurusi ward which are Majenje, Igurusi, Chamoto, Uhambule and Mahango. The study examined critically paddy production for smallholder farmers that practice irrigation and those who cultivates rain-fed paddy. The study examined both existing traditional and modern irrigation systems. It was found that, most of the respondents (79%) practice irrigated agriculture in paddy production while the remaining 21% practice rain-fed agriculture. Forty percent of households that practice irrigated agriculture harvest paddy two seasons per year. The return to labour in paddy production for smallholder farmers who irrigate their paddy fields is about US 2.5/manday which is above the poverty line of US 1.0/day. The smallest return to labour (US $ 0.85/manday) is obtained by an average smallholder farmer who cultivates rain-fed paddy using hand hoe and family labour. The potential implication of the current irrigation systems is that if irrigation is managed properly it may lead to sustainable increases in small farmer’s productivity and income, thus alleviating rural poverty.

The economics of irrigated paddy in Usangu Basin in Tanzania: water utilization, productivity, income and livelihood implications

NASA Astrophysics Data System (ADS)

Kadigi, Reuben M. J.; Kashaigili, Japhet J.; Mdoe, Ntengua S.

Globally, there is a general lack of consensus on how the available water resources can be allocated efficiently and equitably among its competing uses. In irrigated agriculture, this decodes to the central question of how this sector can be balanced in the manner that it produces more ‘crops per drop’ using less water and releasing adequate water for use by other sectors while concurrently enhancing rural income and livelihoods. This requires that the values and costs of irrigated agriculture, at all levels, are well understood and appropriate interventions made. Based on this ground, this paper presents an economic analysis of the value of irrigated paddy in Usangu basin. It attempts to answer the question of what will be the effects if farmers in Usangu stop producing irrigated paddy. The analysis shows that: (a) about 576 mm 3 of water--currently consumed in paddy irrigation, or 345.6 mm 3--traded inter-regionally as “virtual water” would be utilized in alternative ways, either as evaporation from seasonal swamps within the basin or made available for other intersectoral uses, (b) there will be a shrinkage in the annual paddy supply (both at the local and national levels) of about 105,000 t of paddy (66,000 t of rice)-equivalent to 14.4% of the total annual paddy production in Tanzania, (c) an opportunity cost of about US15.9 million will be incurred annually (equivalent to US530.95 per annum per household practicing irrigated paddy in Usangu), and d) the country’s current account of the balance of payments will be affected by an average of US$15.9 million per annum. The effect will either be in form of annual decline in rice exports or increase in imports depending on the country’s supply and demand for rice.

Long term continuous field survey to assess nutrient emission impact from irrigated paddy field into river catchment

NASA Astrophysics Data System (ADS)

Kogure, Kanami; Aichi, Masaatsu; Zessner, Matthias

2017-04-01

In order to achieve good river environment, it is very important to understand and to control nutrient behavior such as Nitrogen and Phosphorus. As we could reduce impact from urban and industrial activities by wastewater treatment, pollution from point sources are likely to be controlled. Besides them, nutrient emission from agricultural activity is dominant pollution source into the river system. In many countries in Asia and Africa, rice is widely cultivated and paddy field covers large areas. In Japan 54% of its arable land is occupied with irrigated paddy field. While paddy field can deteriorate river water quality due to fertilization, it is also suggested that paddy field can purify water. We carried out field survey in middle reach of the Tone River Basin with focus on a paddy field IM. The objectives of the research are 1) understanding of water and nutrient balance in paddy field, 2) data collection for assessing nutrient emission. Field survey was conducted from June 2015 to October 2016 covering two flooding seasons in summer. In our measurement, all input and output were measured regarding water, N and P to quantify water and nutrient balance in the paddy field. By measuring water quality and flow rate of inflow, outflow, infiltrating water, ground water and flooding water, we tried to quantitatively understand water, N and P cycle in a paddy field including seasonal trends, and changes accompanied with rainy events and agricultural activities like fertilization. Concerning water balance, infiltration rate was estimated by following equation. Infiltration=Irrigation water + Precipitation - Evapotranspiration -Outflow We estimated mean daily water balance during flooding season. Infiltration is 11.9mm/day in our estimation for summer in 2015. Daily water reduction depth (WRD) is sum of Evapotranspiration and Infiltration. WRD is 21.5mm/day in IM and agrees with average value in previous research. Regarding nutrient balance, we estimated an annual N and P balance. N and P surplus are calculated by difference between input and output in a paddy field. As to nutrient balance in 2015 surplus shows minus value between input as fertilizer and output as rice product. However, by taking account of input via irrigation water as nutrient source, N and P input and output balance with errors by 9% and 14%. Results of long term continuous survey suggest that irrigation water is one of nutrient sources in rice cultivation.

Transformation of marine sediment to paddy soil: Primary marine, lacustrine, and land plant lipids

NASA Astrophysics Data System (ADS)

Mueller-Niggemann, Cornelia; Cao, Zhihong; Schwark, Lorenz

2010-05-01

More than fifty percent of the world's population feeds on rice. The continuous population increase and urban sprawl leads to an ever-increasing demand for new rice cultivation area, in particular China. For centuries suitable coastal areas in China have been exploited for land reclamation, i.e. conversion of coastal marine and lacustrine marshlands into rice paddy fields. Flooded rice paddies are considered one of the major biogenic sources of methane into the atmospheric. Methane is thought to be about 30 times more efficient as greenhouse gas, when compared to carbon dioxide. Overall, rice fields are assumed to contribute app. 10-25% to global CH4 production. It is thus paramount importance to study the effects of increasing rice cultivation and land reclamation in China. For global carbon cycle investigation, it is crucial whether paddy soils, due to their large extent and higher carbon turnover, serve as carbon (CO2) sinks or sources. Here we present results from a chronosequence study of paddy soils with different and well known starting dates of cultivation, in the Zhejiang province (Yangtze River delta) by land reclamation through the building of protective dikes over the past 2000 years. Two end members of natural sediments subjected to land reclamation, a marine tidal mudflat in the Yangtze delta and a coastal lake, represent the substrate on which the paddy soil evolution started. Dike systems were constructed 2000, 1000, 700, 300, 100, and 50 years before present. We are thus able to follow the evolution of rice paddy soils developed on marine sediments using eight well defined tie-points. This chronosequence is then used for assessing the relative proportion of primary marine or lacustrine organic matter preserved in present day soils and to identify the amount and composition of organic matter added since cultivation started. Paddy soil management introduces rice plants debris and exudates as well as rice-associated microbial biomass (covered in a separate contribution) into soils. Management practises involve burning of rice straw on fields, thus adding biomass combustion residues that either may be particularly stable (e.g. PAH) or highly reactive (alkenes resulting from dehydration of alcohols). Bulk parameters reveal that the five field replicates taken at each site are highly compatible, with standard deviations usually between 0.1 to 5.0 % depending on site and/or parameter. This is better than expected and proves that the samples are representative for each cropping site. The n- and isoalkane composition also proved to be very systematic and reproducible. The marine end-member shows a broad n-alkane envelope from nC13 to nC40, with a maximum of nC31 and low abundance of nC17 and nC32+ alkanes. The lacustrine site also reveals a broad n-alkane envelope and a maximum of nC31 but shows higher relative abundance of nC17, nC23 and nC25 alkanes in addition to a C20-HBI. These biomarkers for aquatic macrophytes and diatoms were also found in minor proportions in paddy soils due to flooding with lacustrine water. Paddy n-alkane patterns were dominated by nC29 which systematically increased in abundance for older paddy soils. Paddy soil n-alkane patterns from the chronosequence are similar and related to the marine pattern. Combustion of rice straw on the field is a common management practise for nutrient return to soils. A rice straw ash sample collected in the field revealed a series of nC13 to nC37 n-alkane/alkene doublets with low odd over even predominance. As no alkenes were found in paddy soils, very fast diagenetic conversion of reactive alkenes must occur. Soil organic matter and aliphatics content increased six fold over a cultivation time of 2000 years, identifying paddies as CO2 sinks in the global carbon cycle.

Direct seeding of shortleaf pine

Treesearch

Corinne S. Mann; David Gwaze

2007-01-01

Direct seeding is a potentially viable method for regenerating shortleaf pine, but it has not been used extensively. In Missouri, an estimated 10,000 acres have been direct-seeded with shortleaf pine; half of which are at Mark Twain National Forest. Direct seeding offers a flexible and efficient alternative to planting as a way to restore shortleaf pine in the Ozarks....

Direct seeding

Treesearch

Richard M. Godman; G. A. Mattson

1992-01-01

At present, direct seeding of hardwoods in the Lake States is more of a supplemental than a primary means of artificial regeneration. Direct seeding may be used to augment a poor seed crop or increase the proportion of a preferred species. In the future, it will no doubt play a bigger role-in anticipation of this we need to collect and store the amounts of seed needed...

Sci-Thur PM – Brachytherapy 02: Positional accuracy in Pd-103 permanent breast seed implant (PBSI) brachytherapy at the Tom Baker Cancer Centre (TBCC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frederick, Amy; Watt, Elizabeth; Peacock, Michael

Purpose: This retrospective study aims to quantify the positional accuracy of seed delivery in permanent breast seed implant (PBSI) brachytherapy at the Tom Baker Cancer Centre (TBCC). Methods: Treatment planning and post-implant CT scans for 5 patients were rigidly registered using the MIM Symphony™ software (MIM Software, Cleveland, OH) and used to evaluate differences between planned and implanted seed positions. Total and directional seed displacements were calculated for each patient in a clinically relevant ‘needle coordinate system’, defined relative to the angle of fiducial needle insertion. Results: The overall average total seed displacement was 10±8 mm. Systematic seed displacements weremore » observed in individual patients and the magnitude and direction of these offsets varied among patients. One patient showed a significant directional seed displacement in the shallow-deep direction compared with the other four patients. With the exception of this one patient outlier, no significant systematic directional displacements in the needle coordinate system were observed for this cohort; the average directional displacements were −1±5 mm, 2±3 mm, and −2±4 mm in the shallow-deep, up-down, and right-left directions respectively. Conclusion: With the exception of one patient outlier, the magnitude of seed displacements were relatively consistent among patients. The results indicate that the shallow-deep direction possesses the largest uncertainty for the seed delivery method used at the TBCC. The relatively large uncertainty in seed placement in this direction is expected, as this is the direction of needle insertion. Further work will involve evaluating deflections of delivered needle tracks from their planned positions.« less

Characterizing spatiotemporal dynamics of methane emissions from rice paddies in Northeast China from 1990 to 2010.

PubMed

Zhang, Yuan; Su, Shiliang; Zhang, Feng; Shi, Runhe; Gao, Wei

2012-01-01

Rice paddies have been identified as major methane (CH(4)) source induced by human activities. As a major rice production region in Northern China, the rice paddies in the Three-Rivers Plain (TRP) have experienced large changes in spatial distribution over the recent 20 years (from 1990 to 2010). Consequently, accurate estimation and characterization of spatiotemporal patterns of CH₄ emissions from rice paddies has become an pressing issue for assessing the environmental impacts of agroecosystems, and further making GHG mitigation strategies at regional or global levels. Integrating remote sensing mapping with a process-based biogeochemistry model, Denitrification and Decomposition (DNDC), was utilized to quantify the regional CH(4) emissions from the entire rice paddies in study region. Based on site validation and sensitivity tests, geographic information system (GIS) databases with the spatially differentiated input information were constructed to drive DNDC upscaling for its regional simulations. Results showed that (1) The large change in total methane emission that occurred in 2000 and 2010 compared to 1990 is distributed to the explosive growth in amounts of rice planted; (2) the spatial variations in CH₄ fluxes in this study are mainly attributed to the most sensitive factor soil properties, i.e., soil clay fraction and soil organic carbon (SOC) content, and (3) the warming climate could enhance CH₄ emission in the cool paddies. The study concluded that the introduction of remote sensing analysis into the DNDC upscaling has a great capability in timely quantifying the methane emissions from cool paddies with fast land use and cover changes. And also, it confirmed that the northern wetland agroecosystems made great contributions to global greenhouse gas inventory.

Characterizing Spatiotemporal Dynamics of Methane Emissions from Rice Paddies in Northeast China from 1990 to 2010

PubMed Central

Zhang, Yuan; Su, Shiliang; Zhang, Feng; Shi, Runhe; Gao, Wei

2012-01-01

Background Rice paddies have been identified as major methane (CH4) source induced by human activities. As a major rice production region in Northern China, the rice paddies in the Three-Rivers Plain (TRP) have experienced large changes in spatial distribution over the recent 20 years (from 1990 to 2010). Consequently, accurate estimation and characterization of spatiotemporal patterns of CH4 emissions from rice paddies has become an pressing issue for assessing the environmental impacts of agroecosystems, and further making GHG mitigation strategies at regional or global levels. Methodology/Principal Findings Integrating remote sensing mapping with a process-based biogeochemistry model, Denitrification and Decomposition (DNDC), was utilized to quantify the regional CH4 emissions from the entire rice paddies in study region. Based on site validation and sensitivity tests, geographic information system (GIS) databases with the spatially differentiated input information were constructed to drive DNDC upscaling for its regional simulations. Results showed that (1) The large change in total methane emission that occurred in 2000 and 2010 compared to 1990 is distributed to the explosive growth in amounts of rice planted; (2) the spatial variations in CH4 fluxes in this study are mainly attributed to the most sensitive factor soil properties, i.e., soil clay fraction and soil organic carbon (SOC) content, and (3) the warming climate could enhance CH4 emission in the cool paddies. Conclusions/Significance The study concluded that the introduction of remote sensing analysis into the DNDC upscaling has a great capability in timely quantifying the methane emissions from cool paddies with fast land use and cover changes. And also, it confirmed that the northern wetland agroecosystems made great contributions to global greenhouse gas inventory. PMID:22235268

In-Situ Quantification of Microbial Processes Controlling Methane Emissions From Rice Plants

NASA Astrophysics Data System (ADS)

Schroth, M. H.; Cho, R.; Zeyer, J. A.

2011-12-01

Methane is an important greenhouse gas contributing to global warming. Among other sources, rice (paddy) soils represent a major nonpoint source of biogenic methane. In flooded paddy soils methane is produced under anaerobic conditions. Conversely, methanotrophic microorganisms oxidize methane to carbon dioxide in the root zone of rice plants, thus reducing overall methane emissions to the atmosphere. We present a novel combination of methods to quantify methanogenesis and methane oxidation in paddy soils and to link methane turnover to net emissions of rice plants. To quantify methane turnover in the presence of high methane background concentrations, small-scale push-pull tests (PPTs) were conducted in paddy soils using stable isotope-labeled substrates. Deuterated acetate and 13-C bicarbonate were employed to discern and quantify acetoclastic and hydrogenotrophic methanogenesis, while 13-C methane was employed to quantify methane oxidation. During 2.5 hr-long PPTs, 140 mL of a test solution containing labeled substrates and nonreactive tracers (Ar, Br-) was injected into paddy soils of potted rice plants. After a short rest period, 480 mL of test solution/pore water mixture was extracted from the same location. Methane turnover was then computed from extraction-phase breakthrough curves of substrates and/or products, and nonreactive tracers. To link methane turnover to net emissions, methane emissions from paddy soils and rice plants were individually determined immediately preceding PPTs using static flux chambers. We will present results of a series of experiments conducted in four different potted rice plants. Preliminary results indicate substantial variability in methane turnover and net emission between different rice plants. The employed combination of methods appears to provide a robust means to quantitatively link methane turnover in paddy soils to net emissions from rice plants.

Waterlogging accelerates the loss of soil organic carbon from abandoned paddy fields in the hilly terrain in subtropical China.

PubMed

Xie, Xiao Li; Wang, Wei; Tian, Wen Wen; Xie, Ke Jun

2017-11-06

Paddy soils have been widely recognized as important carbon sinks. However, paddy field abandonment is increasing in the hilly area in subtropical China. Soil waterlogging and weed burning are common practices in abandoned paddy fields, which could affect vegetation cover and carbon sequestration. An rice cultivation experiment was ceased in 2006, and four new treatments were applied as waterlogging (W), drainage (D), waterlogging combined with burning (WB), and drainage combined with burning (DB). Waterlogging altered the vegetation cover and caused an associated change in biomass. Paspalum paspaloides, Murdannia triquetra, and Bidens frondosa dominated W and WB plots, and Microstegium vimineum and Bidens frondosa dominated D and DB plots. Abandonment of paddy fields led to a rapid decrease in soil organic carbon (SOC), and waterlogging accelerates SOC loss which should be attributed mainly to alteration of the vegetation cover. Six years' rice cultivation increased SOC content by 13.5% (2.4 g kg -1 ) on average. In contrast, six years' abandonment reduced SOC content by 14.5% (3.0 g kg -1 ) on average. Decline rate of SOC was 0.38, 0.64, 0.30, and 0.65 g kg -1 a -1 for D, W, DB, and WB, respectively. Such results indicate a significant risk of SOC loss from abandoned paddy fields.

Metagenomic analysis revealed highly diverse microbial arsenic metabolism genes in paddy soils with low-arsenic contents.

PubMed

Xiao, Ke-Qing; Li, Li-Guan; Ma, Li-Ping; Zhang, Si-Yu; Bao, Peng; Zhang, Tong; Zhu, Yong-Guan

2016-04-01

Microbe-mediated arsenic (As) metabolism plays a critical role in global As cycle, and As metabolism involves different types of genes encoding proteins facilitating its biotransformation and transportation processes. Here, we used metagenomic analysis based on high-throughput sequencing and constructed As metabolism protein databases to analyze As metabolism genes in five paddy soils with low-As contents. The results showed that highly diverse As metabolism genes were present in these paddy soils, with varied abundances and distribution for different types and subtypes of these genes. Arsenate reduction genes (ars) dominated in all soil samples, and significant correlation existed between the abundance of arr (arsenate respiration), aio (arsenite oxidation), and arsM (arsenite methylation) genes, indicating the co-existence and close-relation of different As resistance systems of microbes in wetland environments similar to these paddy soils after long-term evolution. Among all soil parameters, pH was an important factor controlling the distribution of As metabolism gene in five paddy soils (p = 0.018). To the best of our knowledge, this is the first study using high-throughput sequencing and metagenomics approach in characterizing As metabolism genes in the five paddy soil, showing their great potential in As biotransformation, and therefore in mitigating arsenic risk to humans. Copyright © 2015 Elsevier Ltd. All rights reserved.

Clay stabilization by using gypsum and paddy husk ash with reference to UCT and CBR value

NASA Astrophysics Data System (ADS)

Roesyanto; Iskandar, R.; Hastuty, I. P.; Dianty, W. O.

2018-02-01

Clays that have low shear strength need to be stabilized in order to meet the technical requirements to serve as a subgrade material. One of the usual soil stabilization methods is by adding chemicals such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and paddy husk ash. The research goals were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% paddy husk ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT value of original soil was 1.41 kg/cm2. While the CBR soaked and unsoaked values of original soil were 4.41% and 6.23% respectively. The research results showed the addition of paddy husk ash decreased the value of unconfined compressive strength as well as CBR. The stabilized soil by 2% gypsum and 0% paddy husk ash gave maximum UCT value of 1.67 kg/cm2, while the maximum value of CBR were found 6.71% for CBR soaked and 8.00% for CBR unsoaked. The addition of paddy husk ash did not alter the soil classification according to AASHTO or USCS, even degrade the engineering properties of original soil.

Electricity Generation in Microbial Fuel Cell (MFC) by Bacterium Isolated from Rice Paddy Field Soil

NASA Astrophysics Data System (ADS)

Fakhirruddin, Fakhriah; Amid, Azura; Salim, Wan Wardatul Amani Wan; Suhaida Azmi, Azlin

2018-03-01

Microbial fuel cell (MFC) is an alternative approach in generating renewable energy by utilising bacteria that will oxidize organic or inorganic substrates, producing electrons yielded as electrical energy. Different species of exoelectrogenic bacteria capable of generating significant amount of electricity in MFC has been identified, using various organic compounds for fuel. Soil sample taken from rice paddy field is proven to contain exoelectrogenic bacteria, thus electricity generation using mixed culture originally found in the soil, and pure culture isolated from the soil is studied. This research will isolate the exoelectrogenic bacterial species in the rice paddy field soil responsible for energy generation. Growth of bacteria isolated from the MFC is observed by measuring the optical density (OD), cell density weight (CDW) and viable cell count. Mixed bacterial species found in paddy field soil generates maximum power of 77.62 μW and 0.70 mA of current. In addition, the research also shows that the pure bacterium in rice paddy field soil can produce maximum power and current at 51.32 μW and 0.28 mA respectively.

Heavy Metals Uptake by Asian Swamp Eel, Monopterus albus from Paddy Fields of Kelantan, Peninsular Malaysia: Preliminary Study

PubMed Central

Yin, Sow Ai; Ismail, Ahmad; Zulkifli, Syaizwan Zahmir

2012-01-01

Swamp eel, Monopterus albus is one of the common fish in paddy fields, thus it is suitable to be a bio-monitor for heavy metals pollution studies in paddy fields. This study was conducted to assess heavy metals levels in swamp eels collected from paddy fields in Kelantan, Malaysia. The results showed zinc [Zn (86.40 μg/g dry weight)] was the highest accumulated metal in the kidney, liver, bone, gill, muscle and skin. Among the selected organs, gill had the highest concentrations of lead (Pb), cadmium (Cd) and nickel (Ni) whereas muscle showed the lowest total metal accumulation of Zn, Pb, copper (Cu), Cd and Ni. Based on the Malaysian Food Regulation, the levels of Zn and Cu in edible parts (muscle and skin) were within the safety limits. However, Cd, Pb and Ni exceeded the permissible limits. By comparing with the maximum level intake (MLI), Pb, Ni and Cd in edible parts can still be consumed. This investigation indicated that M. albus from paddy fields of Kelantan are safe for human consumption with little precaution. PMID:24575231

Rapid Measurement of Soil Carbon in Rice Paddy Field of Lombok Island Indonesia Using Near Infrared Technology

NASA Astrophysics Data System (ADS)

Kusumo, B. H.; Sukartono, S.; Bustan, B.

2018-02-01

Measuring soil organic carbon (C) using conventional analysis is tedious procedure, time consuming and expensive. It is needed simple procedure which is cheap and saves time. Near infrared technology offers rapid procedure as it works based on the soil spectral reflectance and without any chemicals. The aim of this research is to test whether this technology able to rapidly measure soil organic C in rice paddy field. Soil samples were collected from rice paddy field of Lombok Island Indonesia, and the coordinates of the samples were recorded. Parts of the samples were analysed using conventional analysis (Walkley and Black) and some other parts were scanned using near infrared spectroscopy (NIRS) for soil spectral collection. Partial Least Square Regression (PLSR) Models were developed using data of soil C analysed using conventional analysis and data from soil spectral reflectance. The models were moderately successful to measure soil C in rice paddy field of Lombok Island. This shows that the NIR technology can be further used to monitor the C change in rice paddy soil.

Geofractionation of heavy metals and application of indices for pollution prediction in paddy field soil of Tumpat, Malaysia.

PubMed

Sow, Ai Yin; Ismail, Ahmad; Zulkifli, Syaizwan Zahmir

2013-12-01

The present study investigates the concentration of Pb, Cd, Ni, Zn, and Cu in the paddy field soils collected from Tumpat, Kelantan. Soil samples were treated with sequential extraction to distinguish the anthropogenic and lithogenic origin of Pb, Cd, Ni, Zn, and Cu. ELFE and oxidizable-organic fractions were detected as the lowest accumulation of Pb, Cd, Ni, Zn, and Cu. Therefore, all the heavy metals examined were concentrated, particularly in resistant fraction, indicating that those heavy metals occurred and accumulated in an unavailable form. The utilization of agrochemical fertilizers and pesticides might not elevate the levels of heavy metals in the paddy field soils. In comparison, the enrichment factor and geoaccumulation index for Pb, Cd, Ni, Zn, and Cu suggest that these heavy metals have the potential to cause environmental risk, although they present abundance in resistant fraction. Therefore, a complete study should be conducted based on the paddy cycle, which in turn could provide a clear picture of heavy metals distribution in the paddy field soils.

Actual Condition of Paddy Field Levee Maintenance by Various Farm Households including Large-scale Farming in the Developed Land Renting Area

NASA Astrophysics Data System (ADS)

Sakata, Yasuyo

The survey of interview, resource acquisition, photographic operation, and questionnaire were carried out in the “n” Community in the “y” District in Hakusan City in Ishikawa Prefecture to investigate the actual condition of paddy field levee maintenance in the area where land-renting market was proceeding, large-scale farming was dominant, and the problems of geographically scattered farm-land existed. In the study zone, 1) an agricultural production legal person rent-cultivated some of the paddy fields and maintained the levees, 2) another agricultural production legal person rent-cultivated some of the soy bean fields for crop changeover and land owners maintained the levees. The results indicated that sufficient maintenance was executed on the levees of the paddy fields cultivated by the agricultural production legal person, the soy bean fields for crop changeover, and the paddy fields cultivated by the land owners. Each reason is considered to be the managerial strategy, the economic incentive, the mutual monitoring and cross-regulatory mechanism, etc.

Pre-sowing Seed Treatments in Direct-seeded Early Rice: Consequences for Emergence, Seedling Growth and Associated Metabolic Events under Chilling Stress

NASA Astrophysics Data System (ADS)

Wang, Weiqin; Chen, Qian; Hussain, Saddam; Mei, Junhao; Dong, Huanglin; Peng, Shaobing; Huang, Jianliang; Cui, Kehui; Nie, Lixiao

2016-01-01

Double direct-seeding for double rice cropping is a simplified, labor saving, and efficient cropping system to improve multiple-crop index and total rice production in central China. However, poor crop establishment of direct-seeded early rice due to chilling stress is the main obstacle to wide spread of this system. A series of experiments were conducted to unravel the effects of pre-sowing seed treatments on emergence, seedling growth and associated metabolic events of direct-seeded early rice under chilling stress. Two seed priming treatments and two seed coating treatments were used in all the experiments. A non-treated control treatment was also maintained for comparison. In both the field and growth chamber studies, seed priming with selenium or salicylic acid significantly enhanced the emergence and seedling growth of rice compared with non-treated control. Nevertheless, such positive effects were not apparent for seed coating treatments. Better emergence and vigorous seedling growth of rice after seed priming was associated with enhanced α-amylase activity, higher soluble sugars contents, and greater respiration rate in primed rice seedlings under chilling stress. Taking together, these findings may provide new avenues for understanding and advancing priming-induced chilling tolerance in direct-seeded early rice in double rice cropping system.

Microbial Community and Functional Structure Significantly Varied among Distinct Types of Paddy Soils But Responded Differently along Gradients of Soil Depth Layers

PubMed Central

Bai, Ren; Wang, Jun-Tao; Deng, Ye; He, Ji-Zheng; Feng, Kai; Zhang, Li-Mei

2017-01-01

Paddy rice fields occupy broad agricultural area in China and cover diverse soil types. Microbial community in paddy soils is of great interest since many microorganisms are involved in soil functional processes. In the present study, Illumina Mi-Seq sequencing and functional gene array (GeoChip 4.2) techniques were combined to investigate soil microbial communities and functional gene patterns across the three soil types including an Inceptisol (Binhai), an Oxisol (Leizhou), and an Ultisol (Taoyuan) along four profile depths (up to 70 cm in depth) in mesocosm incubation columns. Detrended correspondence analysis revealed that distinctly differentiation in microbial community existed among soil types and profile depths, while the manifest variance in functional structure was only observed among soil types and two rice growth stages, but not across profile depths. Along the profile depth within each soil type, Acidobacteria, Chloroflexi, and Firmicutes increased whereas Cyanobacteria, β-proteobacteria, and Verrucomicrobia declined, suggesting their specific ecophysiological properties. Compared to bacterial community, the archaeal community showed a more contrasting pattern with the predominant groups within phyla Euryarchaeota, Thaumarchaeota, and Crenarchaeota largely varying among soil types and depths. Phylogenetic molecular ecological network (pMEN) analysis further indicated that the pattern of bacterial and archaeal communities interactions changed with soil depth and the highest modularity of microbial community occurred in top soils, implying a relatively higher system resistance to environmental change compared to communities in deeper soil layers. Meanwhile, microbial communities had higher connectivity in deeper soils in comparison with upper soils, suggesting less microbial interaction in surface soils. Structure equation models were developed and the models indicated that pH was the most representative characteristics of soil type and identified as the key driver in shaping both bacterial and archaeal community structure, but did not directly affect microbial functional structure. The distinctive pattern of microbial taxonomic and functional composition along soil profiles implied functional redundancy within these paddy soils. PMID:28611747

Microbial Community and Functional Structure Significantly Varied among Distinct Types of Paddy Soils But Responded Differently along Gradients of Soil Depth Layers.

PubMed

Bai, Ren; Wang, Jun-Tao; Deng, Ye; He, Ji-Zheng; Feng, Kai; Zhang, Li-Mei

2017-01-01

Paddy rice fields occupy broad agricultural area in China and cover diverse soil types. Microbial community in paddy soils is of great interest since many microorganisms are involved in soil functional processes. In the present study, Illumina Mi-Seq sequencing and functional gene array (GeoChip 4.2) techniques were combined to investigate soil microbial communities and functional gene patterns across the three soil types including an Inceptisol (Binhai), an Oxisol (Leizhou), and an Ultisol (Taoyuan) along four profile depths (up to 70 cm in depth) in mesocosm incubation columns. Detrended correspondence analysis revealed that distinctly differentiation in microbial community existed among soil types and profile depths, while the manifest variance in functional structure was only observed among soil types and two rice growth stages, but not across profile depths. Along the profile depth within each soil type, Acidobacteria , Chloroflexi , and Firmicutes increased whereas Cyanobacteria , β -proteobacteria , and Verrucomicrobia declined, suggesting their specific ecophysiological properties. Compared to bacterial community, the archaeal community showed a more contrasting pattern with the predominant groups within phyla Euryarchaeota , Thaumarchaeota , and Crenarchaeota largely varying among soil types and depths. Phylogenetic molecular ecological network (pMEN) analysis further indicated that the pattern of bacterial and archaeal communities interactions changed with soil depth and the highest modularity of microbial community occurred in top soils, implying a relatively higher system resistance to environmental change compared to communities in deeper soil layers. Meanwhile, microbial communities had higher connectivity in deeper soils in comparison with upper soils, suggesting less microbial interaction in surface soils. Structure equation models were developed and the models indicated that pH was the most representative characteristics of soil type and identified as the key driver in shaping both bacterial and archaeal community structure, but did not directly affect microbial functional structure. The distinctive pattern of microbial taxonomic and functional composition along soil profiles implied functional redundancy within these paddy soils.

Eco-toxicity and metal contamination of paddy soil in an e-wastes recycling area.

PubMed

Jun-hui, Zhang; Hang, Min

2009-06-15

Paddy soil samples taken from different sites in an old primitive electronic-waste (e-waste) processing region were examined for eco-toxicity and metal contamination. Using the environmental quality standard for soils (China, Grade II) as reference, soil samples of two sites were weakly contaminated with trace metal, but site G was heavily contaminated with Cd (6.37 mg kg(-1)), and weakly contaminated with Cu (256.36 mg kg(-1)) and Zn (209.85 mg kg(-1)). Zn appeared to be strongly bound in the residual fraction (72.24-77.86%), no matter the soil was metal contaminated or not. However, more than 9% Cd and 16% Cu was present in the non-residual fraction in the metal contaminated soils than in the uncontaminated soil, especially for site G and site F. Compared with that of the control soil, the micronucleus rates of site G and site F soil treatments increased by 2.7-fold and 1.7-fold, respectively. Low germination rates were observed in site C (50%) and site G (50%) soil extraction treated rice seeds. The shortest root length (0.2377 cm) was observed in site G soil treated groups, which is only 37.57% of that of the control soil treated groups. All of the micronucleus ratio of Vicia faba root cells, rice germination rate and root length after treatment of soil extraction indicate the eco-toxicity in site F and G soils although the three indexes are different in sensitivity to soil metal contamination.

Distribution of tetraether lipids in agricultural soils - differentiation between paddy and upland management

NASA Astrophysics Data System (ADS)

Mueller-Niggemann, C.; Utami, S. R.; Marxen, A.; Mangelsdorf, K.; Bauersachs, T.; Schwark, L.

2015-10-01

Insufficient knowledge of the composition and variation of isoprenoid and branched glycerol dialkyl glycerol tetraethers (GDGTs) in agricultural soils exists, despite of the potential effect of different management types (e.g. soil/water and redox conditions, cultivated plants) on GDGT distribution. Here, we determined the influence of different soil management types on the GDGT composition in paddy (flooded) and adjacent upland (non-flooded) soils, and if available also forest, bushland and marsh soils. To compare the local effects on GDGT distribution patterns, we collected comparable soil samples in various locations from tropical (Indonesia, Vietnam and Philippines) and subtropical (China and Italy) sites. We found that differences in the distribution of isoprenoid GDGTs (iGDGTs) as well as of branched GDGTs (brGDGTs) are predominantly controlled by management type and only secondarily by climatic exposition. In general upland soil had higher crenarchaeol contents than paddy soil, which on the contrary was more enriched in GDGT-0. The GDGT-0 / crenarchaeol ratio was 3-27 times higher in paddy soil and indicates the enhanced presence of methanogenic archaea, which were additionally linked to the number of rice cultivation cycles per year (higher number of cycles was coupled with an increase in the ratio). The TEX86 values were 1.3 times higher in upland, bushland and forest soils than in paddy soils. In all soils brGDGT predominated over iGDGTs, with the relative abundance of brGDGTs increasing from subtropical to tropical soils. Higher BIT values in paddy soils compared to upland soils together with higher BIT values in soil from subtropical climates indicate effects on the amounts of brGDGT through differences in management as well as climatic zones. In acidic soil CBT values correlated well with soil pH. In neutral to alkaline soils, however, no apparent correlation but an offset between paddy and upland managed soils was detected, which may suggest that soil moisture may exert an additional control on the CBT in these soils. Lower MBT' values and calculated temperatures (TMC) in paddy soils compared to upland soils may indicate a management (e.g. enhanced soil moisture through flooding practises) induced effect on mean annual soil temperature (MST).

Direct seeding woody species for restoration of bottomlands

Treesearch

Daniel J. Twedt

2006-01-01

I direct seeded (broadcast) seeds of 39 species of trees and shrubs using an ATV-mounted rotary spreader to initiate restoration of bottomland forest on retired agricultural sites. Four sites were planted during February, 2000, and 13 additional sites were planted during April and May, 2001. After two growing seasons, stem density of direct-seeded species varied...

[Effect of tillage system on soil animal, microorganism and enzyme activity in paddy field].

PubMed

Gao, Ming; Zhou, Baotong; Wei, Chaofu; Xie, Deti; Zhang, Lei

2004-07-01

A long-term experiment showed that under ridge-no-tillage, the amount of soil animal in 0 - 20 cm layer was 14700 ind. x m(-2), while under no-tillage and fallow in winter, paddy-upland rotation, and conventional tillage, it was 10450, 7950 and 6275 ind. x m(-2), respectively. Soil microbial biomass and microbial biomass N were more in spring and autumn, and less in summer. Soil enzyme activity was higher in surface soil layer and lower in bottom soil layer. The amount of soil animal, microbial biomass and microbial biomass N and soil enzyme activity was in order of ridge-no-tillage > paddy-upland rotation > no-tillage and fallow in winter > conventional tillage. The results also indicated that ridge-no-tillage was advantageous to improve soil ecological environment and soil fertility in paddy field.

Effects of biochar on dechlorination of hexachlorobenzene and the bacterial community in paddy soil.

PubMed

Song, Yang; Bian, Yongrong; Wang, Fang; Herzberger, Anna; Yang, Xinglun; Gu, Chenggang; Jiang, Xin

2017-11-01

Anaerobic reductive dechlorination is an important degradation pathway for chlorinated organic contaminants in paddy soil. This study investigated the effects of amending paddy soil with wheat straw biochar on both the dechlorination of hexachlorobenzene (HCB), a typical highly chlorinated contaminant, and on the structure of soil bacteria communities. Soil amendment of 0.1% biochar did not significantly affect the dechlorination of HCB in the soil. However, biochar amendment at higher application levels (5%) stimulated the dechlorination of HCB in the first month of anaerobic incubation and inhibited the dechlorination of HCB after that period. The stimulation effect may be ascribed to the graphite carbon and carbon-centered persistent radicals, which are redox active, in biochar. The inhibiting effect could be partly ascribed to the reduced bioavailability of HCB in biochar-amended soils. High-throughput sequencing revealed that the amendment of biochar changed the soil bacterial community structure but not the bacterial abundances and diversities. The relative abundance of Dehalococcoidaceae in the tested soils showed a significant relationship with the dechlorination percentages of HCB, indicating that Dehalococcoidaceae may be the main HCB-dechlorinating bacteria in the studied paddy soil. The results indicated that low application levels of biochar did not affect the dechlorination of HCB in the paddy soil, while high application levels of biochar mainly inhibited the dechlorination of HCB due to the reduced bioavailability of HCB and the reduced abundances of certain dechlorinating bacteria in the biochar-amended paddy soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial Community and Greenhouse Gas Fluxes from Abandoned Rice Paddies with Different Vegetation.

PubMed

Kim, Sunghyun; Lee, Seunghoon; McCormick, Melissa; Kim, Jae Geun; Kang, Hojeong

2016-10-01

The area of rice paddy fields has declined continuously in East Asian countries due to abandonment of agriculture and concurrent socioeconomic changes. When they are abandoned, rice paddy fields generally transform into wetlands by natural succession. While previous studies have mainly focused on vegetation shifts in abandoned rice paddies, little information is available about how these changes may affect their contribution to wetland functions. As newly abandoned fields proceed through succession, their hydrology and plant communities often change. Moreover, the relationships between these changes, soil microbial characteristics, and emissions of greenhouse gasses are poorly understood. In this study, we examined changes over the course of secondary succession of abandoned rice paddies to wetlands and investigated their ecological functions through changes in greenhouse gas fluxes and microbial characteristics. We collected gas and soil samples in summer and winter from areas dominated by Cyperaceae, Phragmites, and Sphagnum in each site. We found that CO2 emissions in summer were significantly higher than those in winter, but CH4 and N2O emission fluxes were consistently at very low levels and were similar among seasons and locations, due to their low nutrient conditions. These results suggest that microbial activity and abundance increased in summer. Greenhouse gas flux, soil properties, and microbial abundance were not affected by plant species, although the microbial community composition was changed by plant species. This information adds to our basic understanding of the contribution of wetlands that are transformed from abandoned rice paddy systems.

Total mercury and methylmercury concentrations over a gradient of contamination in earthworms living in rice paddy soil.

PubMed

Abeysinghe, Kasun S; Yang, Xiao-Dong; Goodale, Eben; Anderson, Christopher W N; Bishop, Kevin; Cao, Axiang; Feng, Xinbin; Liu, Shengjie; Mammides, Christos; Meng, Bo; Quan, Rui-Chang; Sun, Jing; Qiu, Guangle

2017-05-01

Mercury (Hg) deposited from emissions or from local contamination, can have serious health effects on humans and wildlife. Traditionally, Hg has been seen as a threat to aquatic wildlife, because of its conversion in suboxic conditions into bioavailable methylmercury (MeHg), but it can also threaten contaminated terrestrial ecosystems. In Asia, rice paddies in particular may be sensitive ecosystems. Earthworms are soil-dwelling organisms that have been used as indicators of Hg bioavailability; however, the MeHg concentrations they accumulate in rice paddy environments are not well known. Earthworm and soil samples were collected from rice paddies at progressive distances from abandoned mercury mines in Guizhou, China, and at control sites without a history of Hg mining. Total Hg (THg) and MeHg concentrations declined in soil and earthworms as distance increased from the mines, but the percentage of THg that was MeHg, and the bioaccumulation factors in earthworms, increased over this gradient. This escalation in methylation and the incursion of MeHg into earthworms may be influenced by more acidic soil conditions and higher organic content further from the mines. In areas where the source of Hg is deposition, especially in water-logged and acidic rice paddy soil, earthworms may biomagnify MeHg more than was previously reported. It is emphasized that rice paddy environments affected by acidifying deposition may be widely dispersed throughout Asia. Environ Toxicol Chem 2017;36:1202-1210. © 2016 SETAC. © 2016 SETAC.

High abundance and diversity of nitrite-dependent anaerobic methane-oxidizing bacteria in a paddy field profile.

PubMed

Zhou, Leiliu; Wang, Yu; Long, Xi-En; Guo, Jianhua; Zhu, Guibing

2014-11-01

The discovery of nitrite-dependent anaerobic methane oxidation (n-damo) mediated by 'Candidatus Methylomirabilis oxyfera' with nitrite and methane as substrates has connected biogeochemical carbon and nitrogen cycles in a new way. The paddy fields often carry substantial methane and nitrate, thus may be a favorable habitat for n-damo bacteria. In this paper, the vertical-temporal molecular fingerprints of M. oxyfera-like bacteria, including abundance and community composition, were investigated in a paddy soil core in Jiangyin, near the Yangtze River. Through qPCR investigation, high abundance of M. oxyfera-like bacteria up to 1.0 × 10(8) copies (g d.w.s.)(-1) in summer and 8.5 × 10(7) copies (g d.w.s.)(-1) in winter was observed in the ecotone of soil and groundwater in the paddy soil core, which was the highest in natural environments to our knowledge. In the ecotone, the ratio of M. oxyfera-like bacteria to total bacteria reached peak values of 2.80% in summer and 4.41% in winter. Phylogenetic analysis showed n-damo bacteria in the paddy soil were closely related to M. oxyfera and had high diversity in the soil/groundwater ecotone. All of the results indicated the soil/groundwater ecotone of the Jiangyin paddy field was a favorable environment for the growth of n-damo bacteria. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Numerical simulation of ozone concentration profile and flow characteristics in paddy bulks.

PubMed

Pandiselvam, Ravi; Chandrasekar, Veerapandian; Thirupathi, Venkatachalam

2017-08-01

Ozone has shown the potential to control stored product insect pests. The high reactivity of ozone leads to special problems when it passes though an organic medium such as stored grains. Thus, there is a need for a simulation study to understand the concentration profile and flow characteristics of ozone in stored paddy bulks as a function of time. Simulation of ozone concentration through the paddy grain bulks was explained by applying the principle of the law of conservation along with a continuity equation. A higher ozone concentration value was observed at regions near the ozone diffuser whereas a lower concentration value was observed at regions away from the ozone diffuser. The relative error between the experimental and predicted ozone concentration values for the entire bin geometry was less than 42.8%. The simulation model described a non-linear change of ozone concentration in stored paddy bulks. Results of this study provide a valuable source for estimating the parameters needed for effectively designing a storage bin for fumigation of paddy grains in a commercial scale continuous-flow ozone fumigation system. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Physicochemical Characteristics of Artificial Rice from Composite Flour: Modified Cassava Starch, Canavalia ensiformis and Dioscorea esculenta

NASA Astrophysics Data System (ADS)

Sumardiono, Siswo; Pudjihastuti, Isti; Handayani, Noer Abyor; Kusumayanti, Heny

2018-02-01

Indonesia is the third largest country on the global paddy rice production and also considered as a rice importer. Even, Indonesia has the biggest per capita consumption of paddy rice (140 kg of paddy rice per person per year). Product diversification using local commodities. Artificial rice is potential to be developed as a new value product using different types of grains. It is one of appropriate solutions for reducing imported rice rate. Artificial rice was produced using high nutrition composite flours (modified cassava starch, corn, Canavalian ensiformis, and Dioscorea esculenta). This study consists of three main stages, preparation of composite flour, formulation, and artificial rice production using hot extruder capacity 10 kg/day. The objectives of this studies were to investigate some formulation in compare with commercial paddy rice. Artificial rice has been successfully conducted using prototype of hot extruder with the temperature 95°C. Physical analyses (color and water absorption) were carried out to artificial rice product and commercial paddy rice. Chemical analyses (nutrition and amylose content) of product will be also presented in this study. The best formulation of artificial rice was achieved in 80% modified cassava starch, 10% Canavalian ensiformis, and 10% Dioscorea esculenta, respectively.

Impacts of the herbicide butachlor on the larvae of a paddy field breeding frog (Fejervarya limnocharis) in subtropical Taiwan

USGS Publications Warehouse

Liu, Wan-Yi; Wang, Ching-Yuh; Wang, Tsu-Shing; Fellers, Gary M.; Lai, Bo-Chi; Kam, Yeong-Choy

2011-01-01

Butachlor is the most commonly used herbicide on paddy fields in Taiwan and throughout Southeast Asia. Since paddy fields provide habitat for pond breeding amphibians, we examined growth, development, time to metamorphosis, and survival of alpine cricket frog tadpoles (Fejervarya limnocharis) exposed to environmentally realistic concentrations of butachlor. We documented negative impacts of butachlor on survival, development, and time to metamorphosis, but not on tadpole growth. The 96 h LC50 for tadpoles was 0.87 mg/l, much lower than the 4.8 mg/l recommended dosage for application to paddy fields. Even given the rapid breakdown of butachlor, tadpoles would be exposed to concentrations in excess of their 96 h LC50 for an estimated 126 h. We also documented DNA damage (genotoxicity) in tadpoles exposed to butachlor at concentrations an order of magnitude less than the 4.8 mg/l recommended application rate. We did not find that butachlor depressed cholinesterase activity of tadpoles, unlike most organophosphorus insecticides. We conclude that butachlor is likely to have widespread negative impacts on amphibians occupying paddy fields with traditional herbicide application.

Ameliorants to immobilize Cd in rice paddy soils contaminated by abandoned metal mines in Korea.

PubMed

Ok, Yong Sik; Kim, Sung-Chul; Kim, Dong-Kuk; Skousen, Jeffrey G; Lee, Jin-Soo; Cheong, Young-Wook; Kim, Su-Jung; Yang, Jae E

2011-01-01

The cadmium (Cd) content of rice grain grown in metal-contaminated paddy soils near abandoned metal mines in South Korea was found to exceed safety guidelines (0.2 mg Cd kg⁻¹) set by the Korea Food and Drug Administration (KFDA). However, current remediation technologies for heavy metal-contaminated soils have limited application with respect to rice paddy soils. Laboratory and greenhouse experiments were conducted to assess the effects of amending contaminated rice paddy soils with zerovalent iron (ZVI), lime, humus, compost, and combinations of these compounds to immobilize Cd and inhibit Cd translocation to rice grain. Sequential extraction analysis revealed that treatment with the ameliorants induced a 50-90% decrease in the bioavailable Cd fractions when compared to the untreated control soil. When compared to the control, Cd uptake by rice was decreased in response to treatment with ZVI + humus (69%), lime (65%), ZVI + compost (61%), compost (46%), ZVI (42%), and humus (14%). In addition, ameliorants did not influence rice yield when compared to that of the control. Overall, the results of this study indicated that remediation technologies using ameliorants effectively reduce Cd bioavailability and uptake in contaminated rice paddy soils.

Analysis of rice policy based on presidential instruction on household food security: simultaneous equation model

NASA Astrophysics Data System (ADS)

Sembiring, S. A.

2018-02-01

The objective of this research is to analyze the impacts of rice policy on the household food security. The research used cross section data, were collected from 74 respondent as determined by purposive sampling in Sei Rejo villages, the Sub District of Sei Rampah, Serdang Bedagai District in the Province of North Sumatera. Rice policy model specification uses the simultaneous equations consisting of 6 structural equations and 6 identity equations which was estimated using Two Stages Least Squares (2SLS) method. The results show that the effectiveness of government purchase price of dried harvest paddy gave a positive impact on paddy planted area and lead to an increase paddy production and an increase of the rice production gave a positive impact on household rice availability and household rice surplus, and the increase of household rice surplus gave the quantity of Raskin decrease, whereas the increase of fertilizers gave a negative impact on paddy planted area and lead to decrease paddy production and to decrease in rice production was followed by an decrease in household rice availability and household rice surplus, and the decrease of household rice surplus gave the quantity of Raskin increase.

Impacts of the herbicide butachlor on the larvae of a paddy field breeding frog (Fejervarya limnocharis) in subtropical Taiwan.

PubMed

Liu, Wan-Yi; Wang, Ching-Yuh; Wang, Tsu-Shing; Fellers, Gary M; Lai, Bo-Chi; Kam, Yeong-Choy

2011-03-01

Butachlor is the most commonly used herbicide on paddy fields in Taiwan and throughout Southeast Asia. Since paddy fields provide habitat for pond breeding amphibians, we examined growth, development, time to metamorphosis, and survival of alpine cricket frog tadpoles (Fejervarya limnocharis) exposed to environmentally realistic concentrations of butachlor. We documented negative impacts of butachlor on survival, development, and time to metamorphosis, but not on tadpole growth. The 96 h LC(50) for tadpoles was 0.87 mg/l, much lower than the 4.8 mg/l recommended dosage for application to paddy fields. Even given the rapid breakdown of butachlor, tadpoles would be exposed to concentrations in excess of their 96 h LC(50) for an estimated 126 h. We also documented DNA damage (genotoxicity) in tadpoles exposed to butachlor at concentrations an order of magnitude less than the 4.8 mg/l recommended application rate. We did not find that butachlor depressed cholinesterase activity of tadpoles, unlike most organophosphorus insecticides. We conclude that butachlor is likely to have widespread negative impacts on amphibians occupying paddy fields with traditional herbicide application.

Modelling landscape change in paddy fields using logistic regression and GIS

NASA Astrophysics Data System (ADS)

Franjaya, E. E.; Syartinilia; Setiawan, Y.

2018-05-01

Paddy field in karawang district, as an important agricultural land in west java, has been decreased since 1994. From previous study, paddy fields dominantly turned into built area. The changes were almost occured in the middle area of the district where roadways, industries, settlements, and commercial buildings were existed. These were estimated as driving forces. But, we still need to prove it. This study aimed to construct the paddy field probability change model, subsequently the driving forces will be obtained. GIS combined with logistic regression using environmental variables were used as main method in this study. Ten environmental variables were elevation 0–500 m, elevation>500 m, slope<8%, slope>8%, CBD, build up area, river, irrigation, toll and national roadway, and collector and local roadway. The result indicated that four variables were significantly played as driving forces (slope>8%, CBD area, build up area, and collector and local roadway). Paddy field has high, medium, and low probability to change which covered about 27.8%, 7.8%, and 64.4% area in Karawang respectively. Based on landscape ecology, the recommendation that suitable with landscape change is adaptive management.

A study of the sources and sinks of methane and methyl chloroform using a global three-dimensional Lagrangian tropospheric tracer transport model

NASA Technical Reports Server (NTRS)

Taylor, John A.; Brasseur, G. P.; Zimmerman, P. R.; Cicerone, R. J.

1991-01-01

Sources and sinks of methane and methyl chloroform are investigated using a global three-dimensional Lagrangian tropospheric tracer transport model with parameterized hydroxyl and temperature fields. Using the hydroxyl radical field calibrated to the methyl chloroform observations, the globally averaged release of methane and its spatial and temporal distribution were investigated. Two source function models of the spatial and temporal distribution of the flux of methane to the atmosphere were developed. The first model was based on the assumption that methane is emitted as a proportion of net primary productivity (NPP). The second model identified source regions for methane from rice paddies, wetlands, enteric fermentation, termites, and biomass burning based on high-resolution land use data. The most significant difference between the two models were predictions of methane fluxes over China and South East Asia, the location of most of the world's rice paddies, indicating that either the assumption that a uniform fraction of NPP is converted to methane is not valid for rice paddies, or that NPP is underestimated for rice paddies, or that present methane emission estimates from rice paddies are too high.

Growth and Seed Production of Sawtooth Oak (Quercus acutissima) 22 Years After Direct Seeding

Treesearch

J.C.G. Goelz; D.W. Carlson

1997-01-01

Sawtooth oak (Quercus acutissima Carruth.) was direct seeded at two locations, one with a poorly drained clay soil and the other with a well-drained silty clay loam. For comparison, Nuttall oak (Q. nuttallii Palmer) was direct seeded on the poorly drained clay soil. On the well-drained silty clay loam, sawtooth oak was 18 ft...

Simultaneous enantioselective determination of phenylpyrazole insecticide flufiprole and its chiral metabolite in paddy field ecosystem by ultra-high performance liquid chromatography/tandem mass spectrometry.

PubMed

Li, Jing; Zhang, Yuting; Cheng, Youpu; Yuan, Shankui; Liu, Lei; Shao, Hui; Li, Hui; Li, Na; Zhao, Pengyue; Guo, Yongze

2016-03-20

A novel and sensitive ultra-high performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous enantioselective determination of flufiprole and its hydrolysis metabolite in paddy field ecosystem. The separation and determination were performed using reversed-phase chromatography on a novel cellulose chiral stationary phase, a Lux Cellulose-4 (150 mm × 2.0 mm) column, under isocratic conditions at 0.25 mL/min flow rate. The effects of other four different polysaccharide-based chiral stationary phases (CSPs) on the separation and simultaneous enantioseparation of the two target compounds were also evaluated. The elution orders of the eluting enantiomers were identified by an optical rotation detector. Modified QuEChERS (acronym for Quick, Easy, Cheap, Effective, Rugged and Safe) method and solid-phase extraction (SPE) were used for the enrichment and cleanup of paddy water, rice straw, brown rice and paddy soil samples, respectively. Parameters including the matrix effect, linearity, precision, accuracy and stability were evaluated. Under the optimal conditions, the mean recoveries for all enantiomers from the above four sample matrix were ranged from 83.6% to 107%, with relative standard deviations (RSD) in the range of 1.0-5.8%. Coefficients of determination R(2)≥0.998 were achieved for each enantiomer in paddy water, rice straw, brown rice and paddy soil matrix calibration curves within the range of 5-500 μg/kg. The limits of quantification (LOQ) for all stereoisomers in the above four matrices were all below 2.0 μg/kg. The methodology was successfully applied for simultaneously enantioselective analysis of flufiprole enantiomers and their chiral metabolite in the real samples, indicating its efficacy in investigating the environmental stereochemistry of flufiprole in paddy field ecosystem. Copyright © 2016 Elsevier B.V. All rights reserved.

The variations of Oxidation-Reduction Potential in paddy soil and effects on the methane emission from a periodically irrigated paddy field.

NASA Astrophysics Data System (ADS)

Yagi, K.; Iwata, T.; Wakikuromaru, N.

2014-12-01

Paddy fields are one of the most important eco-system in monsoon Asia and one of the largest source of CH4 emission. CH4 has significant contribution to the global warming next to CO2 and its greenhouse effect is about 21 times as large as same amount of CO2. CH4 is generated by decomposition of organic matter in soil under anaerobic condition. Oxidation-Reduction Potential (ORP) is the most suitable index representing soil aerobic condition. Or, CH4 is more generated under lower ORP conditions. In this study, ORP in paddy soil was measured during rice cultivated season at a periodically irrigated paddy field, and some effects on the methane flux from the paddy soil was investigated. 3-days flood and 4-days drained condition were regularly repeated at the site from late-June to early October. ORP under flooded condition was measured during irrigated term in 2013 at two mode; regular interval measurement every 2 weeks and intensive measurements during two flooded periods. Methane flux was also measured by the aerodynamic gradient technique. ORP showed rapid decrease when irrigation water was introduced in the paddy field, and lower ORP was shown under the longer flooded condition. From the seasonal-term point of view, lower ORP was shown in later rice season. ORP was suitably modeled as a function of irrigation time. During an irrigation period for four days, higher methane emissions were shown under lower OPR conditions as shown in Fig.1. From the seasonal-term point of view, however, no significant relationship between ORP and methane fluxes. Rapid rise of CH4 flux in early August and gradual decrease between late August and September were shown. It is suggested that seasonal change of methane flux is affected by seasonal changes of soil temperature or the growth level of rice plants.

Selenium inhibits sulfate-mediated methylmercury production in rice paddy soil.

PubMed

Wang, Yong-Jie; Dang, Fei; Zhao, Jia-Ting; Zhong, Huan

2016-06-01

There is increasing interest in understanding factors controlling methylmercury (MeHg) production in mercury-contaminated rice paddy soil. Sulfate has been reported to affect MeHg biogeochemistry under anoxic conditions, and recent studies revealed that selenium (Se) could evidently reduce MeHg production in paddy soil. However, the controls of sulfate and Se on net MeHg production in paddy soil under fluctuating redox conditions remain largely unknown. Microcosm experiments were conducted to explore the effects of sulfate and Se on net MeHg production in rice paddy soil. Soil was added with 0-960 mg/kg sulfate, in the presence or absence of 3.0 mg/kg selenium (selenite or selenate), and incubated under anoxic (40 days) or suboxic conditions (5 days), simulating fluctuating redox conditions in rice paddy field. Sulfate addition moderately affected soil MeHg concentrations under anoxic conditions, while reoxidation resulted in evidently higher (18-40%) MeHg levels in sulfate amended soils than the control. The observed changes in net MeHg production were related to dynamics of sulfate and iron. However, Se could inhibit sulfate-mediated MeHg production in the soils: Se addition largely reduced net MeHg production in the soils (23-86%, compared to the control), despite of sulfate addition. Similarly, results of the pot experiments (i.e., rice cultivation in amended soils) indicated that soil MeHg levels were rather comparable in Se-amended soils during rice growth period, irrespective of added sulfate doses. The more important role of Se than sulfate in controlling MeHg production was explained by the formation of HgSe nanoparticles irrespective of the presence of sulfate, confirmed by TEM-EDX and XANES analysis. Our findings regarding the effects of sulfate and Se on net MeHg production in rice paddy soil together with the mechanistic explanation of the processes advance our understanding of MeHg dynamics and risk in soil-rice systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Control of arsenic mobilization in paddy soils by manganese and iron oxides.

PubMed

Xu, Xiaowei; Chen, Chuan; Wang, Peng; Kretzschmar, Ruben; Zhao, Fang-Jie

2017-12-01

Reductive mobilization of arsenic (As) in paddy soils under flooded conditions is an important reason for the relatively high accumulation of As in rice, posing a risk to food safety and human health. The extent of As mobilization varies widely among paddy soils, but the reasons are not well understood. In this study, we investigated As mobilization in six As-contaminated paddy soils (total As ranging from 73 to 122 mg kg -1 ) in flooded incubation and pot experiments. Arsenic speciation in the solution and solid phases were determined. The magnitude of As mobilization into the porewater varied by > 100 times among the six soils. Porewater As concentration correlated closely with the concentration of oxalate-extractable As, suggesting that As associated with amorphous iron (oxyhydr)oxides represents the potentially mobilizable pool of As under flooded conditions. Soil containing a high level of manganese oxides showed the lowest As mobilization, likely because Mn oxides retard As mobilization by slowing down the drop of redox potential upon soil flooding and maintaining a higher arsenate to arsenite ratio in the solid and solution phases. Additions of a synthetic Mn oxide (hausmannite) to two paddy soils increased arsenite oxidation, decreased As mobilization into the porewater and decreased As concentrations in rice grain and straw. Consistent with previous studies using simplified model systems or pure mineral phases, the present study shows that Mn oxides and amorphous Fe (oxyhydr)oxides are important factors controlling reductive As mobilization in As-contaminated paddy soils. In addition, this study also suggests a potential mitigation strategy using exogenous Mn oxides to decrease As uptake by rice in paddy soils containing low levels of indigenous Mn oxides, although further work is needed to verify its efficacy and possible secondary effects under field conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like polychlorinated biphenyls in rice straw smoke and their origins in Japan.

PubMed

Minomo, Kotaro; Ohtsuka, Nobutoshi; Nojiri, Kiyoshi; Hosono, Shigeo; Kawamura, Kiyoshi

2011-08-01

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) contained in the smoke generated from rice straw burning in post-harvest paddy fields in Japan were analyzed to determine their congener profiles. Both the apportionment of toxic equivalent (TEQ) by using indicative congeners and the comparison of the homolog profiles showed that the PCDDs/PCDFs/DL-PCBs present in the rice-straw smoke were greatly influenced by those present as impurities in pentachlorophenol (PCP) and chlornitrofen (CNP, 4-nitrophenyl-2,4,6-trichlorophenyl ether) formulations that had been widely used as herbicides in paddy fields in Japan. Further, in order to investigate the effects of paddy-field soil on the PCDDs/PCDFs/DL-PCBs present in rice-straw smoke, PCDD/PCDF/DL-PCB homolog profiles of rice straw, rice-straw smoke and paddy-field soil were compared. Rice-straw smoke was generated by burning rice straw on a stainless-steel tray in a laboratory. The results suggested that the herbicides-originated PCDDs/PCDFs/DL-PCBs and the atmospheric PCDDs/PCDFs/DL-PCBs contributed predominantly to the presence of PCDDs/PCDFs/DL-PCBs in the rice-straw smoke while the contribution of PCDDs/PCDFs/DL-PCBs formed during rice straw burning was relatively minimal. The major sources of the PCDDs/PCDFs/DL-PCBs found in the rice-straw smoke were attributed primarily to the paddy-field soil adhered to the rice straw surface and secondarily to the air taken by the rice straw. The principal component analysis supported these conclusions. It is concluded that rice straw burning at paddy fields acts as a driving force in the transfer of PCDDs/PCDFs/DL-PCBs from paddy-field soil to the atmosphere. Copyright © 2011 Elsevier Ltd. All rights reserved.

A repellent to reduce mouse damage to longleaf pine seed

Treesearch

Dale L. Nolte; James P. Barnett

2000-01-01

Direct seeding is a potential method for reforestation of pines on many southern sites. The success of direct seeding, however, depends, at least in part, in reducing seed predation by birds and rodents. We conducted a series of tests to assess the efficacy of capsicum and thiram in reducing mouse damage to longleaf pine (Pinus palustris) seeds....

JPRS Report, China

DTIC Science & Technology

1989-10-31

technology of deep and inclined well drilling on land and sea, and the popularization of break spinning and air-jet weaving. Apart from this, 70 percent of...husked sorghum; millet and millet con- verted to husked millet , and other raw grains and raw grains converted to grain products. Tubers included sweet...threshed, but that had not yet been milled, and that could be directly eaten without being processed. Wheat, paddy, soybeans, sorghum, millet , corn, broad

Grazing disturbance increases transient but decreases persistent soil seed bank.

PubMed

Ma, Miaojun; Walck, Jeffrey L; Ma, Zhen; Wang, Lipei; Du, Guozhen

2018-04-30

Very few studies have examined whether the impacts of grazing disturbance on soil seed banks occur directly or indirectly through aboveground vegetation and soil properties. The potential role of the seed bank in alpine wetland restoration is also unknown. We used SEM (structural equation modeling) to explore the direct effect of grazing disturbance on the seed bank and the indirect effect through aboveground vegetation and soil properties. We also studied the role of the seed bank on the restoration potential in wetlands with various grazing intensities: low (fenced, winter grazed only), medium (seasonally grazed), and high (whole-year grazed). For the seed bank, species richness and density per plot showed no difference among grazing intensities for each depth (0-5, 5-10, 10-15 cm) and for the whole depth (0-15 cm) in spring and summer. There was no direct effect of grazing disturbance on seed bank richness and density both in spring and summer, and also no indirect effect on the seed bank through its direct effect on vegetation richness and abundance. Grazing disturbance indirectly increased spring seed bank density but decreased summer seed bank density through its direct effect (negative correlation) on soil moisture and total nitrogen and its indirect effect on vegetation abundance. Species composition of the vegetation changed with grazing regime, but that of the seed bank did not. An increased trend of similarity between the seed bank and aboveground vegetation with increased grazing disturbance was found in the shallow depth and in the whole depth only in spring. Although there was almost no change in seed bank size with grazing intensities, grazing disturbance increased the quantity of transient seeds but decreased persistent seeds. Persistent seeds stored in the soil could play a crucial role in vegetation regeneration and in restoration of degraded wetland ecosystems. The seed bank should be an integral part of alpine wetland restoration programs. © 2018 by the Ecological Society of America.

Can't see the forest for the rice: factors influencing spatial variations in the density of trees in paddy fields in northeast Thailand.

PubMed

Watanabe, Moriaki; Vityakon, Patma; Rambo, A Terry

2014-02-01

The widespread presence of trees in paddy fields is a unique feature of Northeast Thailand's agricultural landscape. A survey of spatial variability in the density of trees in paddy fields in the Northeast Region was conducted utilizing high resolution satellite images and found that the mean density in the whole region was 12.1 trees/ha (varying from a high of 44.6 trees/ha to a low of 0.8 trees/ha). In general, tree densities are higher in the southeastern part of the region and much lower in the northern central part. Tree density was influenced by multiple factors including: (1) the history of land development, with more recently developed paddy fields having higher densities, (2) topography, with fields located at higher topographical positions having a higher mean density of trees, (3) access to natural forest resources, with fields in areas located close to natural forests having higher densities, (4) amount of annual rainfall, with fields in areas with higher average annual rainfall having higher tree densities, and (5) landholding size, with fields in areas with larger-sized landholdings having more trees. However, there is a considerable extent of co-variation among these factors. Although trees remain an important element of the paddy field landscape in the Northeast, it appears that their density has been declining in recent years. If this trend continues, then the vast "invisible forest" represented by trees in paddy fields may truly disappear, with negative consequences for the villagers' livelihoods, biodiversity conservation, and carbon sequestration in the rural ecosystem.

A weighted least squares estimation of the polynomial regression model on paddy production in the area of Kedah and Perlis

NASA Astrophysics Data System (ADS)

Musa, Rosliza; Ali, Zalila; Baharum, Adam; Nor, Norlida Mohd

2017-08-01

The linear regression model assumes that all random error components are identically and independently distributed with constant variance. Hence, each data point provides equally precise information about the deterministic part of the total variation. In other words, the standard deviations of the error terms are constant over all values of the predictor variables. When the assumption of constant variance is violated, the ordinary least squares estimator of regression coefficient lost its property of minimum variance in the class of linear and unbiased estimators. Weighted least squares estimation are often used to maximize the efficiency of parameter estimation. A procedure that treats all of the data equally would give less precisely measured points more influence than they should have and would give highly precise points too little influence. Optimizing the weighted fitting criterion to find the parameter estimates allows the weights to determine the contribution of each observation to the final parameter estimates. This study used polynomial model with weighted least squares estimation to investigate paddy production of different paddy lots based on paddy cultivation characteristics and environmental characteristics in the area of Kedah and Perlis. The results indicated that factors affecting paddy production are mixture fertilizer application cycle, average temperature, the squared effect of average rainfall, the squared effect of pest and disease, the interaction between acreage with amount of mixture fertilizer, the interaction between paddy variety and NPK fertilizer application cycle and the interaction between pest and disease and NPK fertilizer application cycle.

Diversity of Cultivable Methane-Oxidizing Bacteria in Microsites of a Rice Paddy Field: Investigation by Cultivation Method and Fluorescence in situ Hybridization (FISH)

PubMed Central

Dianou, Dayéri; Ueno, Chihoko; Ogiso, Takuya; Kimura, Makoto; Asakawa, Susumu

2012-01-01

The diversity of cultivable methane-oxidizing bacteria (MOB) in the rice paddy field ecosystem was investigated by combined culture-dependent and fluorescence in situ hybridization (FISH) techniques. Seven microsites of a Japanese rice paddy field were the focus of the study: floodwater, surface soil, bulk soil, rhizosphere soil, root, basal stem of rice plant, and rice stumps of previous harvest. Based on pmoA gene analysis and transmission electron microscopy (TEM), four type I, and nine type II MOB isolates were obtained from the highest dilution series of enrichment cultures. The type I MOB isolates included a novel species in the genus Methylomonas from floodwater and this is the first type I MOB strain isolated from floodwater of a rice paddy field. In the type I MOB, two isolates from stumps were closely related to Methylomonas spp.; one isolate obtained from rhizosphere soil was most related to Methyloccocus-Methylocaldum-Methylogaea clade. Almost all the type II MOB isolates were related to Methylocystis methanotrophs. FISH confirmed the presence of both types I and II MOB in all the microsites and in the related enrichment cultures. The study reported, for the first time, the diversity of cultivable methanotrophs including a novel species of type I MOB in rice paddy field compartments. Refining growth media and culture conditions, in combination with molecular approaches, will allow us to broaden our knowledge on the MOB community in the rice paddy field ecosystem and consequently to implement strategies for mitigating CH4 emission from this ecosystem. PMID:22446309

Reducing CH4 emission from rice paddy fields by altering water management

NASA Astrophysics Data System (ADS)

Sudo, S.; Itoh, M.

2010-12-01

Percentage of atmospheric methane emitted form rice paddy is estimated at 60Tg/yr (20 - 100Tg/yr) which is near 10% of total global methane emission of 535Tg/yr (410 - 660Tg) (IPCC(1995), and which is near 30% of anthropogenic CH4 emission. Thus, mitigation of CH4 emission is urgently required. CH4 in paddy soil is emanated by the activities of anaerobic bacteria which is called methane producer through reduction of CO2 or decomposition of acetic acid, and it is transported to atmosphere through soil or paddy water surface. It is effective to control methane emission from rice paddy that period is extended on intermittent drainage, composted rice straw is incorporated as fertilizer instead of flesh one, or other. However, empirical approach of these kinds of experiments had not been sufficient because such a kind of experiment required significant times and efforts. In this study, we conducted demonstrative experiments to verify the effects of water management method differences in order to reduce CH4 emission from rice paddy at 9 experimental sites in 8 prefectures. In this, we used new gas analyzer which can measure CH4, CO2 and N2O at once developed by National Institute for Agro-Environmental Sciences (NIAES), Japan. In this report, we show the results in two years of this study. 'Nakaboshi' (mid-season-drainage) is one of cultivation methods in rice paddy that surface water in paddy field is once drained for about 10 days and the field is maintained like upland field to give adequate stress to rice plant for better harvest qualities and yields. Our targeted evaluation was dependencies of Nakaboshi periods lengths and Nakaboshi periods to CH4 emission reduction amounts for total cultivation periods within harvest yield maintained. The longer length of Nakaboshi period was extended, the lesser CH4 emitted even after when Nakaboshi period lasted, as a whole. In some cases, for example in Kagoshima, exceptional phenomena of that significant high emission were observed at a later stage of cultivation season (around the end of August). Adjusting of Nakaboshi periods did not make effective performance in such cases. In most of cases, emission increase of N2O was not found during prolonged Nakaboshi period.

Identification of transplanting stage of rice using Sentinel-1 data

NASA Astrophysics Data System (ADS)

Hongo, C.; Tosa, T.; Tamura, E.; Sigit, G.; Barus, B.

2017-12-01

As the adaptation of climate change, the Government of Indonesia has launched agricultural insurance program for damage of rice by drought, flood and pest and disease. For assessment of the damage ratio and calculation of indemnity, extraction of paddy field and identification of transplanting stage are key issues. In this research, we conducted identification of rice transplanting stage in dry season of 2015, using data from Sentinel-1, for paddy in Cianjur, West Java, Indonesia. As the first step, time series order of backscattering coefficient was analyzed about paddy, forest, villages and fish farming ponds with use of Sentinel-1 data acquired on April 1, April 13, April 25, May 7, May 19, June 24, July 18 and August 11. The result shows that the backscattering coefficient of paddy substantially decreased from data on May 7 and reached minimum value and then after increased toward June. A paddy area showing this change was almost the same area where rice was at harvesting stage and we did field investigation work from August 11 to 13. Considering a growth period of rice in our research site was about 110 days, so the result supported the fact that transplantation of rice was done around May 7. On the other hand, backscattering coefficient of forest, villages and fish farming ponds was constant and showed clear difference from the coefficient of paddy. As the next step, minimum and maximum value of backscattering coefficient were extracted from the data of May 7, May 19 and June 24, respectively. Then increase amount was calculated by deducting the minimum value from the maximum. Finally, using the minimum value of backscattering coefficient and the increased amount, a classification of image was made to identify transplanting stage through maximum likelihood method, decision tree method and threshold setting method (regression analysis by 3σ-rule). As the result, the maximum likelihood method made the most accurate distinguishment about transplanting stage while the decision tree method showed tendency to underestimate a paddy area already planted. As to the threshold setting method (regression analysis by 3σ-rule), its distinguishment accuracy was better than those of other methods about a paddy area adjacent to forest and villages of which backscattering coefficient was influenced by other sources' coefficients.

Spatial and Temporal Variations of Rice Paddy as Influenced by Climate Change in the Sanjiang Plain, Northeastern China

NASA Astrophysics Data System (ADS)

Chen, J.; Liu, Q.; Ma, L.; Hou, S.; Tao, B.

2014-12-01

The Sanjiang Plain is located in the eastern part of Heilongjiang Province, Northeastern China, and represents one of major agricultural regions nationwide. Over past decades, this region has seen intensive cropland reclamation and a sharp shrinkage of natural vegetation and water bodies, driven by not only policy-making and economic development, but also a warming climate. However, it still remains unclear how climate change has influenced the magnitude and spatial patterns of land use changes. In this study, we examined spatial and temporal variations of rice paddy planting area during 1980-2008 through an integration of the remote-sensing images, the census data, and other existing land use/cover data sets. The daily gridded climate data sets were generated by using an interpolation method of thin plate smoothing splines, based on observations from over 70 meteorological stations across the study area. Our results suggest that the rice paddy planting area increased by more than 10-fold during 1980-2008, with more obvious upward trends during two sub-periods, i.e. 1995-1998 and 2004-2008. Further analyses indicated that the rice paddy planting area accounted for approximately 20.3% of total cropland area in 2008, increasing more than seven-fold as compared to 1980. When investigating spatially, we found that the planting boundary of rice paddy expanded northward for roughly 2 degree, comparing to 1984 when most of rice paddies were found in the north of the 48o N. Most of increases of rice paddy planting area occurred in the northeast of the study region. The climate analyses showed a significant warming trend, with a slightly decrease in precipitation. During the study period, the suitable areas for rice production increased about 25% and expanded northward clearly. Our study demonstrated how climate change influenced the magnitude and spatial patterns of rice paddy planting area in the Sanjiang Plain, which could provide scientific information for the environmental assessment and related policy-making. It implies that climate change could result in substantial land use/cover changes through climate adaption strategies that humans adopted. While, how to compromise those adaption strategies and environmental sustainability (e.g., preserving water resources and biodiversity) need further invstigation.

Root-Derived Short-Chain Suberin Diacids from Rice and Rape Seed in a Paddy Soil under Rice Cultivar Treatments

PubMed Central

Ji, Haishi; Ding, Yuanjun; Liu, Xiaoyu; Li, Lianqing; Zhang, Dengxiao; Li, Zichuan; Sun, Jingling; Lashari, Muhammad Siddique; Joseph, Stephen; Meng, Yuanduo; Kuzyakov, Yakov; Pan, Genxing

2015-01-01

Suberin-derived substituted fatty acids have been shown to be potential biomarkers for plant-derived carbon (C) in soils across ecosystems. Analyzing root derived suberin compounds bound in soil could help to understand the root input into a soil organic carbon pool. In this study, bound lipids were extracted and identified in root and topsoil samples. Short-chain suberin diacids were quantified under rice (Oryza sativa L.) and rape (Brassica campestris) rotations with different cultivar combinations in a Chinese rice paddy. After removal of free lipids with sequential extraction, the residual bound lipids were obtained with saponification and derivatization before analysis using gas chromatography–mass spectrometry (GC-MS). Diacids C16 and C18 in bound lipids were detected both in rice and rape root samples, while diacids C20 and C22 were detected only in rape root samples. Accordingly, diacids were quantified in both rhizosphere and bulk soil (0–15 cm). The amount of total root-derived diacids in bulk soil varied in a range of 5.6–9.6 mg/kg across growth stages and crop seasons. After one year-round rice-rape rotation, root-derived suberin diacids were maintained at a level of 7–9 mg/kg in bulk soil; this was higher under a super rice cultivar LY than under a hybrid cultivar IIY. While concentrations of the analyzed diacids were generally higher in rhizosphere than in bulk soil, the total diacid (DA) concentration was higher at the time of rape harvest than at rice harvest, suggesting that rape roots made a major contribution to the preservation of diacids in the paddy. Moreover, the net change in the concentration and the ratios of C16:0 DA to C18:1 DA, and of C16:0 DA to C18:0 DA, over a whole growing season, were greater under LY than under IIY, though there was no difference between cultivars within a single growth stage. Overall, total concentration of root-derived suberin diacids was found to be positively correlated to soil organic carbon concentration both for bulk soil and rhizosphere. However, the turnover and preservation of the root suberin biomolecules with soil property and field conditions deserve further field studies. PMID:25961557

Root-Derived Short-Chain Suberin Diacids from Rice and Rape Seed in a Paddy Soil under Rice Cultivar Treatments.

PubMed

Ji, Haishi; Ding, Yuanjun; Liu, Xiaoyu; Li, Lianqing; Zhang, Dengxiao; Li, Zichuan; Sun, Jingling; Lashari, Muhammad Siddique; Joseph, Stephen; Meng, Yuanduo; Kuzyakov, Yakov; Pan, Genxing

2015-01-01

Suberin-derived substituted fatty acids have been shown to be potential biomarkers for plant-derived carbon (C) in soils across ecosystems. Analyzing root derived suberin compounds bound in soil could help to understand the root input into a soil organic carbon pool. In this study, bound lipids were extracted and identified in root and topsoil samples. Short-chain suberin diacids were quantified under rice (Oryza sativa L.) and rape (Brassica campestris) rotations with different cultivar combinations in a Chinese rice paddy. After removal of free lipids with sequential extraction, the residual bound lipids were obtained with saponification and derivatization before analysis using gas chromatography-mass spectrometry (GC-MS). Diacids C16 and C18 in bound lipids were detected both in rice and rape root samples, while diacids C20 and C22 were detected only in rape root samples. Accordingly, diacids were quantified in both rhizosphere and bulk soil (0-15 cm). The amount of total root-derived diacids in bulk soil varied in a range of 5.6-9.6 mg/kg across growth stages and crop seasons. After one year-round rice-rape rotation, root-derived suberin diacids were maintained at a level of 7-9 mg/kg in bulk soil; this was higher under a super rice cultivar LY than under a hybrid cultivar IIY. While concentrations of the analyzed diacids were generally higher in rhizosphere than in bulk soil, the total diacid (DA) concentration was higher at the time of rape harvest than at rice harvest, suggesting that rape roots made a major contribution to the preservation of diacids in the paddy. Moreover, the net change in the concentration and the ratios of C16:0 DA to C18:1 DA, and of C16:0 DA to C18:0 DA, over a whole growing season, were greater under LY than under IIY, though there was no difference between cultivars within a single growth stage. Overall, total concentration of root-derived suberin diacids was found to be positively correlated to soil organic carbon concentration both for bulk soil and rhizosphere. However, the turnover and preservation of the root suberin biomolecules with soil property and field conditions deserve further field studies.

Effect of Drying on Heavy Metal Fraction Distribution in Rice Paddy Soil

PubMed Central

Qi, Yanbing; Huang, Biao; Darilek, Jeremy Landon

2014-01-01

An understanding of how redox conditions affect soil heavy metal fractions in rice paddies is important due to its implications for heavy metal mobility and plant uptake. Rice paddy soil samples routinely undergo oxidation prior to heavy metal analysis. Fraction distribution of Cu, Pb, Ni, and Cd from paddy soil with a wide pH range was investigated. Samples were both dried according to standard protocols and also preserved under anaerobic conditions through the sampling and analysis process and heavy metals were then sequentially extracted for the exchangeable and carbonate bound fraction (acid soluble fraction), iron and manganese oxide bound fraction (reducible fraction), organic bound fraction (oxidizable fraction), and residual fraction. Fractions were affected by redox conditions across all pH ranges. Drying decreased reducible fraction of all heavy metals. Curesidual fraction, Pboxidizable fraction, Cdresidual fraction, and Niresidual fraction increased by 25%, 33%, 35%, and >60%, respectively. Pbresidual fraction, Niacid soluble fraction, and Cdoxidizable fraction decreased 33%, 25%, and 15%, respectively. Drying paddy soil prior to heavy metal analysis overestimated Pb and underestimated Cu, Ni, and Cd. In future studies, samples should be stored after injecting N2 gas to maintain the redox potential of soil prior to heavy metal analysis, and investigate the correlation between heavy metal fraction distribution under field conditions and air-dried samples. PMID:24823670

Risk Assessment of Heavy Metals Contamination in Paddy Soil, Plants, and Grains (Oryza sativa L.) at the East Coast of India

PubMed Central

Satpathy, Deepmala; Reddy, M. Vikram; Dhal, Soumya Prakash

2014-01-01

Heavy metals known to be accumulated in plants adversely affect human health. This study aims to assess the effects of agrochemicals especially chemical fertilizers applied in paddy fields, which release potential toxic heavy metals into soil. Those heavy metals get accumulated in different parts of paddy plant (Oryza sativa L.) including the grains. Concentrations of nonessential toxic heavy metals (Cd, Cr, and Pb) and the micronutrients (Cu, Mn, and Zn) were measured in the paddy field soil and plant parts. Mn and Cd are found to be accumulated more in shoot than in root. The metal transfer factors from soil to rice plant were significant for Pb, Cd, Cu, Cr, Mn, and Zn. The ranking order of bioaccumulation factor (BAF) for heavy metals was Zn > Mn > Cd > Cu > Cr > Pb indicating that the accumulation of micronutrients was more than that of nonessential toxic heavy metals. The concentrations of heavy metals were found to be higher in paddy field soils than that of the nearby control soil but below permissible limits. The higher Health Index (HI) values of rice consuming adults (1.561) and children (1.360) suggest their adverse health effects in the near future. PMID:24995308

Resistance of Rice Varieties to the Stored-Product Insect, Sitophilus zeamais (Coleoptera: Curculionidae).

PubMed

Antunes, Catarina; Mendes, Raquel; Lima, Arlindo; Barros, Graça; Fields, Paul; Da Costa, Luísa Beirão; Rodrigues, José Carlos; Silva, Maria José; Correia, Augusto Manuel; Carvalho, Maria Otilia

2016-02-01

Four common Portuguese rice varieties--Thaibonnet, Gladio, Albatros, and Eurosis--were tested for their relative susceptibility to Sitophilus zeamais Motschulsky, a common pest of stored rice in Portugal and in tropical countries. Physical (moisture content, hardness, length, and width) and chemical (by attenuated total reflection-Fourier transform infrared spectroscopy) properties of rice kernels were measured. Insect bioassays measured median developmental time, Dobie's index of susceptibility, percentage of damaged grains and weight loss, and progeny developed. This was done for paddy, brown rice, and polished rice for each variety. There were small, but significant, differences in insect resistance among the varieties. However, it was different for paddy and polished rice. In paddy, these differences were correlated with hull damage, and Eurosis was the most susceptible variety. In polished rice, resistance was correlated with hardness, and Thaibonnet was the most susceptible variety. In general, paddy rice was more resistant to insect attack, followed by polished rice and then brown rice. Paddy kernels selected with undamaged hull were completely resistant to attack. Implications for IPM and breeding for resistant varieties are discussed. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Improvement of red pepper yield and soil environment by summer catch aquatic crops in greenhouses

NASA Astrophysics Data System (ADS)

Du, X. F.; Wang, L. Z.; Peng, J.; Wang, G. L.; Guo, X. S.; Wen, T. G.; Gu, D. L.; Wang, W. Z.; Wu, C. W.

2016-08-01

To investigate effects of the rotation of summer catch crops on remediation retrogressed soils in continuous cropping, a field experiment was conducted. Rice, water spinach, or cress were selected as summer catch crops; bare fallow during summer fallow was used as the control group. Results showed that aquatic crops grown in summer fallow period could effectively reduce soil bulk density and pH, facilitate soil nutrient release, and improve soil physical and chemical properties compared with those grown in fallow period. Paddy-upland rotation could improve soil microbial members and increase bacterial and actinomycete populations; by contrast, paddy-upland rotation could reduce fungal populations and enhance bacterium-to-fungus ratio. Paddy-upland rotation could also actively promote activities of soil enzymes, such as urease, phosphatase, invertase, and catalase. The proposed paddy-upland rotation significantly affected the growth of red pepper; the yield and quality of the grown red pepper were enhanced. Summer catch crops, such as rice, water spinach, and cress significantly increased pepper yield in the following growing season by 15.4%, 10.2% and 14.0%, respectively, compared with those grown in fallow treatment. Therefore, the proposed paddy-upland crop rotation could be a useful method to alleviate continuous cropping problems involved in cultivating red pepper in greenhouses.

Efficient Arsenic Methylation and Volatilization Mediated by a Novel Bacterium from an Arsenic-Contaminated Paddy Soil.

PubMed

Huang, Ke; Chen, Chuan; Zhang, Jun; Tang, Zhu; Shen, Qirong; Rosen, Barry P; Zhao, Fang-Jie

2016-06-21

Microbial arsenic (As) methylation and volatilization are important processes controlling the As biogeochemical cycle in paddy soils. To further understand these processes, we isolated a novel bacterial strain, SM-1, from an As-contaminated paddy soil. SM-1 showed strong As methylation and volatilization abilities, converting almost all arsenite (10 μM) to dimethylarsenate and trimethylarsenic oxide in the medium and trimethylarsine gas into the headspace within 24 h, with trimethylarsine accounting for nearly half of the total As. On the basis of the 16S rRNA sequence, strain SM-1 represents a new species in a new genus within the family Cytophagaceae. Strain SM-1 is abundant in the paddy soil and inoculation of SM-1 greatly enhanced As methylation and volatilization in the soil. An arsenite methyltransferase gene (ArarsM) was cloned from SM-1. When expressed in Escherichia coli, ArArsM conferred the As methylation and volatilization abilities to E. coli and increased its resistance to arsenite. The high As methylation and volatilization abilities of SM-1 are likely attributed to an efficient ArArsM enzyme coupled with low arsenite efflux. These results suggest that strain SM-1 plays an important role in As methylation and volatilization in the paddy soil and has a great potential for As bioremediation.

Assessment of indoor pollutants generated from bio and synthetic fuels in selected villages of Burdwan, West Bengal.

PubMed

Mondal, N K; Bhaumik, R; Das, C R; Aditya, P; Datta, J K; Banerjee, A; Das, K

2013-09-01

The objective of the present study was to access the pollutant generated from bio-fuels like bamboo sticks, cow dung, paddy straw, carbon dust cake, gobar gas, jute stick, and mustard stick and synthetic fuel like LPG during cooking in rural villages of Burdwan, West Bengal, India and its fluctuation in living room. The average SO2 released from the fuels was found in the following order: bamboo stick > cow dung > paddy straw > carbon cake > gobar gas > jute stick > LPG > mustard stick; NO2 emission was in the following order : mustard stick > carbon dust cake > paddy straw > cow dung cake > LPG, jute stick > gobar gas > bamboo stick > and SPM was obtained in the following sequence: cow dung cake > bamboo stick > carbon dust cake > gobar gas > LPG > mustard stick > paddy straw > jute stick, respectively. The highest living room to kitchen room (L/K) ratio of SO2, NO, and SPM was found in LPG, gobar gas, jute stick respectively in 2009 and followed by bamboo stick > paddy straw > jute stick > cow dung cake, respectively in 2010. Results of this study suggest that different fuels released different amount of air pollutants, but more extensive study is needed to confirm the relationship between fuels and released air pollutants.

[Long-term effects of tillage methods on heavy metal accumulation and availability in purple paddy soil].

PubMed

Chang, Tong-Ju; Cui, Xiao-Qiang; Ruan, Zhen; Zhao, Xiu-Lan

2014-06-01

A long-term experiment, conducted at Southwest University since 1990, was used to evaluate the effect of tillage methods on the total and available contents of heavy metals (Fe, Mn, Cu, Zn, Pb, Cd) in the profile of purple paddy soil and the contents of those metals in root, stem leaf and brown rice. The experiment included five tillage methods: conventional tillage, paddy-upland rotation, no-tillage and fallow in winter, ridge-no-tillage and compartments-no-tillage. The results showed that the total concentrations of Fe, Cu, Zn, Pb and Cd in the soil profile had no significant differences among five treatments, but it was found that total Mn has a significant decline in 0-20 cm under conventional tillage, paddy-upland rotation and no-tillage and fallow in winter compared with ridge-no-tillage and compartments-no-tillage. The availability of Fe, Cu, Zn, Pb and Cd decreased with the increase of soil depth in all treatments, but the availability of Mn was found to be the highest in the 20-40 cm layers except those in the paddy-upland rotation. In the ploughed layer, the contents of available Fe, Mn was the highest in paddy-upland rotation, while the contents of available Zn and Pb was the highest in conventional tillage, but tillage treatments had not significant influence to the contents of available Cu. Correlation analysis showed that available Fe was significantly negatively related to the pH values and significantly negatively related to the organic matter of soils, available Mn was significantly negatively related to the pH values and organic matter of soils, whereas the available Zn was significantly positively related to total Zn. The contents of Fe, Mn in rice root, the contents of Fe, Mn, Cu and Cd in rice straw and Cu in brown rice were higher under paddy-upland rotation, ridge-no-tillage and compartments-no-tillage than those in conventional tillage and no-tillage and fellow in winter. Paddy-upland rotation can significantly lower the migration coefficient value of Cd in brown rice, and the Pb, Cd concentration in brown rice in the treatment of paddy-upland rotation was lower than the upper limit (< 0.2 mg x kg(-1)) of the National Standard for Food Hygiene for Cd concentration. The content of Fe in root was significantly and negatively related with soil pH and significantly and positively related with soil available Fe, the content of Mn in root was significantly negatively related with soil pH and significantly positively related with soil available Mn, the content of Mn in straw was significantly negatively related with soil pH, significantly positively related with soil total Mn and significantly positively related with soil available Mn, the content of Cu in straw and brown rice was significantly negatively related with soil pH, the content of Zn was significant related with soil pH and significant related with soil CEC. The content of Fe in root, Mn in root and straw and Cd in straw was positively related with soil available Fe, Mn and Cd, respectively, but was negatively related with pH in plough layer soil, Zn in straw was also negatively related with plough layer soil pH. From the results as above, it is concluded that different tillage methods can change the values of soil pH, alter the availability of heavy metal in soils, consequently affect uptake of heavy metal by rice. Of the tillage methods, paddy-upland rotation could increase the availability of Fe and Mn, but decrease the availability of Zn, Pb and Cd in purple paddy soils. Paddy-upland rotation can also increase the contents of Fe, Mn in rice root and straw, but decrease Cd content in brown rice, and could reduce the Pb, Cd contents in brown rice in a certain extent, however, attention should be given to long-term paddy-upland rotation cause of leaching of soil surface Mn.

Direct seeding of fine hardwood tree species

Treesearch

Lenny D. Farlee

2013-01-01

Direct seeding of fine hardwood trees has been practiced in the Central Hardwoods Region for decades, but results have been inconsistent. Direct seeding has been used for reforestation and afforestation based on perceived advantages over seedling planting, including cost and operational efficiencies, opportunities for rapid seedling establishment and early domination...

Seed distribution of four co-occurring grasses around Artemisia halodendron shrubs in a sandy habitat

NASA Astrophysics Data System (ADS)

Li, Feng-Rui; Zhao, Wen-Zhi; Kang, Ling-Fen; Liu, Ji-Liang; Huang, Zhi-Gang; Wang, Qi

2009-05-01

In a natural population of the perennial semi-shrub Artemisia halodendron in a shifting sandy habitat in the Horqin Desert of eastern Inner Mongolia, six isolated adult A. halodendron individuals of similar canopy size were chosen as target plants. The density of seeds in the top 5 cm soil depth around shrubs was measured using transects aligned to the four main wind directions and at different distances from the shrub base on both the windward and leeward sides. The effects of shrub presence on seed distribution of four co-occurring grasses were examined by linking seed distribution to seed traits. Of the four species, Setaris viridis and Eragrostis pilosa had small but similar seed mass, while Chloris virgata and Aristida adscensionis had large but similar seed mass. The species were grouped into two cohorts: small-seeded vs. large-seeded cohorts, and shrub presence effects on seed distribution of both cohorts were examined. We found marked difference in the seed distribution pattern among species, especially between the small-seeded and large-seeded cohorts. The small-seeded cohort had significantly higher seed accumulation on the windward than the leeward sides in the most and least prevailing wind directions and much higher seed accumulation on the leeward than the windward sides in the second and third most prevailing wind directions, while opposite patterns occurred in the large-seeded cohort. Four species also showed marked variation in the seed distribution pattern among transects and between windward and leeward sides of each transect. This study provided further evidence that shrubs embedded in a matrix of herbaceous plants is a key cause of spatial heterogeneity in seed availability of herbaceous species. However, seed distribution responses to the presence of shrubs will vary with species as well as with wind direction, sampling position (windward vs. leeward sides of the shrub) and distance from the shrub.

Evaluation of ferrolysis in arsenate adsorption on the paddy soil derived from an Oxisol.

PubMed

Jiang, Jun; Dai, Zhaoxia; Sun, Rui; Zhao, Zhenjie; Dong, Ying; Hong, Zhineng; Xu, Renkou

2017-07-01

Iron oxides are dominant effective adsorbents for arsenate in iron oxide-rich variable charge soils. Oxisol-derived paddy soils undergo intensive ferrolysis, which results in high leaching and transformation of iron oxides. However, little information is available concerning the effect of ferrolysis on arsenate adsorption by paddy soil and parent Oxisol. In the present study, we examined the arsenate affinity of soils using arsenate adsorption/desorption isotherms, zeta potential, adsorption kinetics, pH effect and phosphate competition experiments. Results showed that ferrolysis in an alternating flooding-drying Oxisol-derived paddy soil resulted in a significant decrease of free iron oxides and increase of amorphous iron oxides in the surface and subsurface layers. There were more reactive sites exposed on amorphous than on crystalline iron oxides. Therefore, disproportionate ratios of arsenate adsorption capacities and contents of free iron oxides were observed in the studied Oxisols compared with paddy soils. The Gibbs free energy values corroborated that both electrostatic and non-electrostatic adsorption mechanisms contributed to the arsenate adsorption by bulk soils, and the kinetic adsorption data further suggested that the rate-limiting step was chemisorption. The zeta potential of soil colloids decreased after arsenate was adsorbed on the surfaces, forming inner-sphere complexes and thus transferring their negative charges to the soil particle surfaces. The adsorption/desorption isotherms showed that non-electrostatic adsorption was the main mechanism responsible for arsenate binding to the Oxisol and derived paddy soils, representing 91.42-94.65% of the adsorption capacities. Further studies revealed that arsenate adsorption was greatly inhibited by increasing suspension pH and incorporation of phosphate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodegradation of paddy straw obtained from different geographic locations by means of Phlebia spp. for animal feed.

PubMed

Sharma, Rakesh Kumar; Arora, Daljit Singh

2011-02-01

Various cereal straws are used as feed by supplementing the green forage or other feed stuffs. An experiment was designed to see the effect of different geographic locations and climatological conditions on biochemical constituents, fungal degradation and in vitro digestibility of paddy straw. Paddy straw (PS) obtained from three different geographic locations of India was subjected to solid state fermentation using four white rot fungi i.e. Phlebia brevispora, P. fascicularia, P. floridensis and P. radiata. Changes in the biochemical constituents like water soluble content, hemicellulose, cellulose, lignin, total organic matter, and in vitro digestibility of paddy straw was analyzed over a period of 60 days along with lignocellulolytic enzymes i.e. laccase, xylanase and carboxymethyl cellulase. All the fungi degraded the straw samples and enhanced the in vitro digestibility. The paddy straw, obtained from north western zone (NWZ) suffered a maximum loss (228 g/kg) of lignin by P. radiata, while a maximum enhancement of in vitro digestibility from 185 to 256 g/kg was achieved by P. brevispora, which also caused minimum loss in total organic matter (98 g/kg). In PS obtained from central eastern zone (CEZ) and north eastern zone (NEZ), a maximum amount of lignin (210 and 195 g/kg, respectively) was degraded by P. floridensis and resulted into a respective enhancement of in vitro digestibility from 172 to 246 g/kg and 188 to 264 g/kg. The study demonstrates that geographic locations not only affect the biochemical constituents of paddy straw but the fungal degradation of fibers, their in vitro digestibility and lignocellulolytic enzyme activity of the fungus may also vary.

Effect of allelopathic rice varieties combined with cultural management options on paddy field weeds.

PubMed

Kong, Chui-Hua; Hu, Fei; Wang, Peng; Wu, Jing-Lun

2008-03-01

A number of techniques, including cultural management, allelopathy and bioherbicide, have been considered as alternatives for synthetic herbicides, but successful weed control will require the careful integration of these multiple techniques. This study was conducted to assess the use of allelopathic rice varieties in combination with cultural management options on paddy weeds, in order to develop an allelopathy-based technique to reduce herbicide use in paddies. The weed-suppressive effects of the rice varieties tested varied highly with allelopathic trait, planting pattern and cultural management including planting density, flooding depth and duration and supply of nitrogen. Allelopathic rice varieties PI312777 and Huagan-1 demonstrated much stronger weed suppression than the non-allelopathic variety Huajianxian under the same planting pattern and cultural management. Their weed-suppressive effect was increased with cultural management options. In particular, if integrated cultural management options of allelopathic rice varieties included a low-dose (bensulfuron-methyl, 25 g AI ha(-1), a third of the recommended dose) herbicide application, the emergence and growth of most weeds found in paddy fields was completely controlled. No grain yield reduction for allelopathic varieties occurred under integrated cultural management options, whereas with the non-allelopathic variety a reduction of up to 45-60% was measurable even with the low-dose herbicide application. The allelopathic potential of rice varieties will likely have a great impact on paddy weed control if integrated with cultural management options and application of low doses of herbicides. Therefore, it is feasible to reduce herbicide input in paddies if allelopathic rice is grown under integrated cultural management practices. (c) 2008 Society of Chemical Industry.

Arsenic contamination in the food chain and its risk assessment of populations residing in the Mekong River basin of Cambodia.

PubMed

Phan, Kongkea; Sthiannopkao, Suthipong; Heng, Savoeun; Phan, Samrach; Huoy, Laingshun; Wong, Ming Hung; Kim, Kyoung-Woong

2013-11-15

In the present study, we investigated the potential arsenic exposure of Cambodian residents from their daily food consumption. Environmental and ecological samples such as paddy soils, paddy rice (unhusked), staple rice (uncooked and cooked), fish and vegetables were collected from Kandal, Kratie and Kampong Cham provinces in the Mekong River basin of Cambodia. After acid-digestion, digestates were chemically analyzed by inductively coupled plasma mass spectrometry. Results revealed that the means of total arsenic concentration ([As]tot) in paddy soils and paddy rice from Kandal were significantly higher than those from Kampong Cham province (t-test, p<0.05). Moreover, a significant positive correlation between the [As]tot in paddy soils and paddy rice was found (r(14) = 0.826, p<0.01). Calculations of arsenic intake from food consumption indicated that the upper end of the range of the daily dose of inorganic arsenic for Kandal residents (0.089-8.386 μg d(-1) kg(-1) body wt.) was greater than the lower limits on the benchmark dose for a 0.5% increased incidence of lung cancer (BMDL0.5 is equal to 3.0 μg d(-1) kg(-1) body wt.). The present study suggests that the residents in Kandal are at risk of arsenic intake from their daily food consumption. However, the residents in Kratie and Kampong Cham provinces are less likely to be exposed to arsenic through their daily dietary intake. To the best of our knowledge, this is the first report estimating the daily intake and daily dose of inorganic arsenic from food consumption in the Mekong River basin of Cambodia. Copyright © 2012 Elsevier B.V. All rights reserved.

[Effect of flooding time on community structure and abundance of Geobacteraceae in paddy soil].

PubMed

You, Jiaohua; Xia, Shuhong; Wang, Baoli; Qu, Dong

2011-06-01

The dynamic characteristics of community structure and relative abundance of Geobacteraceae were investigated to understand their response to microbial iron (III) reducing in flooded paddy soil. The paddy soil was incubated anaerobically and the amount of Fe(II) was determined during the flooding incubation. We retrieved Geobacteraceae sequences from clone libraries constructed for different time points (1 h and day 1, 5, 10, 20 and 30) after flooding of the paddy soil. The diversity and community structure were analyzed by using RFLP method, and the relative abundance of Geobacteraceae was detected by real-time PCR. Microbial reduction of iron (III) changed greatly in early time and was stable after incubated for 20 d in paddy soil. The largest iron reduction potential was 10.16 mg/g with a Vmax of 1.064 mg/(g x d) at the time of 4.84 d whereas this process achieved plateau after 20 days flooding. Diversity of Geobacteraceae, given by alpha indices, fluctuated during the flooding incubation. Two peaks of diversity were observed in treatments of 5 d and 20 d respectively, while significant low diversity appeared in samples of 10 d and 30 d. Beta indices described the differences between community structures of Geobacteraceae and hence reflected the variation of the flooding situation over time. In all samples, 10 RFLP-based preponderant types were found, which fell into clade 1 and clade 2 of Geobacteraceae. The relative abundance of Geobacteraceae was the lowest in 1 d (1.20% ) and the highest in 20 d (4.54%). The dynamic variation of Geobacteraceae diversity, community structure and abundance are closely related to microbial iron (III) reducing in flooding paddy soil.

Characterization, identification and application of lactic Acid bacteria isolated from forage paddy rice silage.

PubMed

Ni, Kuikui; Wang, Yanping; Li, Dongxia; Cai, Yimin; Pang, Huili

2015-01-01

There has been growing interest to develop forage rice as a new feed resource for livestock. This study was to characterize the natural population of lactic acid bacteria (LAB) and select potentially excellent strains for paddy rice silage preparation in China. One hundred and twenty-six strains were isolated and screened from paddy rice silage prepared using a small-scale fermentation system, and ninety-nine of these isolates were considered to be LAB based on their Gram-positive and catalase-negative morphology and the production of most of their metabolic products as lactic acid. These isolates were divided into eight groups (A-H) on the basis of their morphological and biochemical characteristics. The Group A to H strains were identified as Lactobacillus (L.) plantarum subsp. plantarum (species ratio: 8.1%), L. casei (5.1%), Leuconostoc (Ln.) pseudomesenteroides (11.1%), Pediococcus (P.) pentosaceus (24.2%), Enterococcus (E.) mundtii (12.1%), Lactococcus (Lc.) garvieae (15.2%), E. faecium (9.1%) and Lc. lactis subsp. lactis (15.2%) based on sequence analyses of their 16S rRNA and recA genes. P. pentosaceus was the most abundant member of the LAB population in the paddy rice silage. A selected strain, namely L. casei R 465, was found to be able to grow under low pH conditions and to improve the silage quality with low pH and a relatively high content of lactic acid. This study demonstrated that forage paddy rice silage contains abundant LAB species and its silage can be well preserved by inoculation with LAB, and that strain R 465 can be a potentially excellent inoculant for paddy rice silage.

Characterization, Identification and Application of Lactic Acid Bacteria Isolated from Forage Paddy Rice Silage

PubMed Central

Ni, Kuikui; Wang, Yanping; Li, Dongxia; Cai, Yimin; Pang, Huili

2015-01-01

There has been growing interest to develop forage rice as a new feed resource for livestock. This study was to characterize the natural population of lactic acid bacteria (LAB) and select potentially excellent strains for paddy rice silage preparation in China. One hundred and twenty-six strains were isolated and screened from paddy rice silage prepared using a small-scale fermentation system, and ninety-nine of these isolates were considered to be LAB based on their Gram-positive and catalase-negative morphology and the production of most of their metabolic products as lactic acid. These isolates were divided into eight groups (A-H) on the basis of their morphological and biochemical characteristics. The Group A to H strains were identified as Lactobacillus (L.) plantarum subsp. plantarum (species ratio: 8.1%), L. casei (5.1%), Leuconostoc (Ln.) pseudomesenteroides (11.1%), Pediococcus (P.) pentosaceus (24.2%), Enterococcus (E.) mundtii (12.1%), Lactococcus (Lc.) garvieae (15.2%), E. faecium (9.1%) and Lc. lactis subsp. lactis (15.2%) based on sequence analyses of their 16S rRNA and recA genes. P. pentosaceus was the most abundant member of the LAB population in the paddy rice silage. A selected strain, namely L. casei R 465, was found to be able to grow under low pH conditions and to improve the silage quality with low pH and a relatively high content of lactic acid. This study demonstrated that forage paddy rice silage contains abundant LAB species and its silage can be well preserved by inoculation with LAB, and that strain R 465 can be a potentially excellent inoculant for paddy rice silage. PMID:25803578

pH regulates ammonia-oxidizing bacteria and archaea in paddy soils in Southern China.

PubMed

Li, Hu; Weng, Bo-Sen; Huang, Fu-Yi; Su, Jian-Qiang; Yang, Xiao-Ru

2015-07-01

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrogen cycling. However, the effects of environmental factors on the activity, abundance, and diversity of AOA and AOB and the relative contributions of these two groups to nitrification in paddy soils are not well explained. In this study, potential nitrification activity (PNA), abundance, and diversity of amoA genes from 12 paddy soils in Southern China were determined by potential nitrification assay, quantitative PCR, and cloning. The results showed that PNA was highly variable between paddy soils, ranging from 4.05 ± 0.21 to 9.81 ± 1.09 mg NOx-N kg(-1) dry soil day(-1), and no significant correlation with soil parameters was found. The abundance of AOA was predominant over AOB, indicating that AOA may be the major members in aerobic ammonia oxidation in these paddy soils. Community compositions of AOA and AOB were highly variable among samples, but the variations were best explained by pH. AOA sequences were affiliated to the Nitrosopumilus cluster and Nitrososphaera cluster, and AOB were classified into the lineages of Nitrosospira and Nitrosomonas, with Nitrosospira being predominant over Nitrosomonas, accounting for 83.6 % of the AOB community. Moreover, the majority of Nitrosomonas was determined in neutral soils. Canonical correspondence analysis (CCA) analysis further demonstrated that AOA and AOB community structures were significantly affected by pH, soil total organic carbon, total nitrogen, and C/N ratio, suggesting that these factors exert strong effects on the distribution of AOB and AOA in paddy soils in Southern China. In conclusion, our results imply that soil pH was a key explanatory variable for both AOA and AOB community structure and nitrification activity.

Spatial distribution of heavy metal contamination in soils near a primitive e-waste recycling site.

PubMed

Quan, Sheng-Xiang; Yan, Bo; Yang, Fan; Li, Ning; Xiao, Xian-Ming; Fu, Jia-Mo

2015-01-01

The total concentrations of 12 heavy metals in surface soils (SS, 0-20 cm), middle soils (MS, 30-50 cm) and deep soils (DS, 60-80 cm) from an acid-leaching area, a deserted paddy field and a deserted area of Guiyu were measured. The results showed that the acid-leaching area was heavily contaminated with heavy metals, especially in SS. The mean concentrations of Ni, Cu, Zn, Cd, Sn, Sb and Pb in SS from the acid-leaching area were 278.4, 684.1, 572.8, 1.36, 3,472, 1,706 and 222.8 mg/kg, respectively. Heavy metal pollution in the deserted paddy field was mainly concentrated in SS and MS. The average values of Sb in SS and MS from the deserted paddy field were 16.3 and 20.2 mg/kg, respectively. However, heavy metal contamination of the deserted area was principally found in the DS. Extremely high concentrations of heavy metals were also observed at some special research sites, further confirming that the level of heavy metal pollution was very serious. The geoaccumulation index (Igeo) values revealed that the acid-leaching area was severely polluted with heavy metals in the order of Sb > Sn > Cu > Cd > Ni > Zn > Pb, while deserted paddy field was contaminated predominately by metals in the order of Sb > Sn > Cu. It was obvious that the concentrations of some uncommon contaminants, such as Sb and Sn, were higher than principal contaminants, such as Ni, Cu, Zn and Pb, suggesting that particular attention should be directed to Sn and Sb contamination in the future research of heavy metals in soils from e-waste-processing areas. Correlation analysis suggested that Li and Be in soils from the acid-leaching area and its surrounding environment might have originated from other industrial activities and from batteries, whereas Ni, Cu, Zn, Cd, Pb, Sn and Sb contamination was most likely caused by uncontrolled electronic waste (e-waste) processing. These results indicate the significant need for optimisation of e-waste-dismantling technologies and remediation of polluted soil environment.

Effects of sulfur in flooded paddy soils: Implications for iron chemistry and arsenic mobilization

NASA Astrophysics Data System (ADS)

Avancha, S.; Boye, K.

2013-12-01

In the Mekong delta in Cambodia, naturally occurring arsenic (amplified by erosion in the Himalaya Mountains) in paddy soils is mobilized during the seasonal flooding. As a consequence, rice grown on the flooded soils may take up arsenic and expose people eating the rice to this carcinogenic substance. Iron and sulfur both interact strongly with arsenic in paddy soils: iron oxides are strong adsorbents for arsenic in oxic conditions, and sulfur (in the form of sulfide) is a strong adsorbent under anoxic conditions. In the process of reductive dissolution of iron oxides, arsenic, which had been adsorbed to the iron oxides, is released. Therefore, higher levels of reduced iron (ferrous iron) will likely correlate with higher levels of mobilized arsenic. However, the mobilized arsenic may then co-precipitate with or adsorb to iron sulfides, which form under sulfate-reducing conditions and with the aid of certain microbes already present in the soil. In a batch experiment, we investigated how these processes correlate and which has the greatest influence on arsenic mobilization and potential plant availability. The experiment was designed to measure the effects of various sources of sulfur (dried rice straw, charred rice straw, and gypsum) on the iron and arsenic release in an arsenic-contaminated paddy soil from Cambodia under flooded conditions. The two types of rice straw were designed to introduce the same amount of organic sulfur (7.7 μg/g of soil), but different levels of available carbon, since carbon stimulates microbial activity in the soil. In comparison, two different levels of gypsum (calcium sulfate) were used, 7.7 and 34.65 μg/g of soil, to test the effect of directly available inorganic sulfate without carbon addition. The soil was flooded with a buffer solution at pH 7.07 in airtight serum vials and kept as a slurry on a shaker at 25 °C. We measured pH, alkalinity, ferrous iron, ferric iron, sulfide, sulfate, total iron, sulfur, and arsenic in the aqueous phase on days 1, 3, 8, 15, 22, 29 and 38 from the start of the experiment.

Tier I Rice Model - Version 1.0 - Guidance for Estimating Pesticide Concentrations in Rice Paddies

EPA Pesticide Factsheets

Describes a Tier I Rice Model (Version 1.0) for estimating surface water exposure from the use of pesticides in rice paddies. The concentration calculated can be used for aquatic ecological risk and drinking water exposure assessments.

Microbial community analysis in rice paddy soils irrigated by acid mine drainage contaminated water.

PubMed

Sun, Min; Xiao, Tangfu; Ning, Zengping; Xiao, Enzong; Sun, Weimin

2015-03-01

Five rice paddy soils located in southwest China were selected for geochemical and microbial community analysis. These rice fields were irrigated with river water which was contaminated by Fe-S-rich acid mine drainage. Microbial communities were characterized by high-throughput sequencing, which showed 39 different phyla/groups in these samples. Among these phyla/groups, Proteobacteria was the most abundant phylum in all samples. Chloroflexi, Acidobacteria, Nitrospirae, and Bacteroidetes exhibited higher relative abundances than other phyla. A number of rare and candidate phyla were also detected. Moreover, canonical correspondence analysis suggested that pH, sulfate, and nitrate were significant factors that shaped the microbial community structure. In addition, a wide diversity of Fe- and S-related bacteria, such as GOUTA19, Shewanella, Geobacter, Desulfobacca, Thiobacillus, Desulfobacterium, and Anaeromyxobacter, might be responsible for biogeochemical Fe and S cycles in the tested rice paddy soils. Among the dominant genera, GOUTA19 and Shewanella were seldom detected in rice paddy soils.

[Effects of different multiple cropping systems on paddy field weed community under long term paddy-upland rotation].

PubMed

Yang, Bin-Juan; Huang, Guo-Qin; Xu, Ning; Wang, Shu-Bin

2013-09-01

Based on a long term field experiment, this paper studied the effects of different multiple cropping systems on the weed community composition and species diversity under paddy-upland rotation. The multiple cropping rotation systems could significantly decrease weed density and inhibited weed growth. Among the rotation systems, the milk vetch-early rice-late maize --> milk vetchearly maize intercropped with early soybean-late rice (CCSR) had the lowest weed species dominance, which inhibited the dominant weeds and decreased their damage. Under different multiple cropping systems, the main weed community was all composed of Monochoia vaginalis, Echinochloa crusgalli, and Sagittaria pygmae, and the similarity of weed community was higher, with the highest similarity appeared in milk vetch-early rice-late maize intercropped with late soybean --> milk vetch-early maize-late rice (CSCR) and in CCSR. In sum, the multiple cropping rotations in paddy field could inhibit weeds to a certain extent, but attentions should be paid to the damage of some less important weeds.

Nitrogen removal function of recycling irrigation system.

PubMed

Hitomi, T; Yoshinaga, I; Feng, Y W; Shiratani, E

2006-01-01

The purpose of this study was to clarify the nitrogen (N) purification capacity of a paddy field in a recycling irrigation system. Irrigation water was sampled at 12-h intervals during the irrigation period from April to September 2003. In addition, ponded water in a paddy field was collected at three points (inlet, centre and outlet). Total amounts of N were 30.7 kg ha(-1) in inflow and 27.8 kg ha(-1) in outflow. Thus, the net outflow load was -2.9 kg ha(-1). The N removal rate constant when N removal is expressed as a 1st-order kinetic was 0.017-0.024 m d(-1). This value is close to values of wetlands and paddy fields in the literature. We found a good correlation between recycling ratio and N removal effect. These results indicate that the recycling irrigation system accumulates N in the irrigation/drainage system, and thus the paddy field does a good job of water purification by removing N.

The effects of rice canopy on the air-soil exchange of polycyclic aromatic hydrocarbons and organochlorine pesticides using paired passive air samplers.

PubMed

Wang, Yan; Wang, Shaorui; Luo, Chunling; Li, Jun; Ming, Lili; Zhang, Gan; Li, Xiangdong

2015-05-01

The rice canopy in paddy fields can influence the air-soil exchange of organic chemicals. We used paired passive air samplers to assess the exchange of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in a paddy field, South China. Levels of OCPs and light PAHs were generally higher under the canopy than above it. We found that the rice canopy can physically obstruct the evaporation of most OCPs and light PAHs, and can also act as a barrier to the gaseous deposition of p,p'-DDT and heavy PAHs. Paddy fields can behave as a secondary source of OCPs and light PAHs. The homolog patterns of these two types of chemical varied slightly between the air below and above the rice canopy, implying contributions of different sources. Paired passive air samplers can be used effectively to assess the in situ air-soil exchange of PAHs and OCPs in subtropical paddy fields. Copyright © 2015 Elsevier Ltd. All rights reserved.

Seed Placement in Permanent Breast Seed Implant Brachytherapy: Are Concerns Over Accuracy Valid?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morton, Daniel, E-mail: dmorton@bccancer.bc.ca; Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia; Hilts, Michelle

Purpose: To evaluate seed placement accuracy in permanent breast seed implant brachytherapy (PBSI), to identify any systematic errors and evaluate their effect on dosimetry. Methods and Materials: Treatment plans and postimplant computed tomography scans for 20 PBSI patients were spatially registered and used to evaluate differences between planned and implanted seed positions, termed seed displacements. For each patient, the mean total and directional seed displacements were determined in both standard room coordinates and in needle coordinates relative to needle insertion angle. Seeds were labeled according to their proximity to the anatomy within the breast, to evaluate the influence of anatomicmore » regions on seed placement. Dosimetry within an evaluative target volume (seroma + 5 mm), skin, breast, and ribs was evaluated to determine the impact of seed placement on the treatment. Results: The overall mean (±SD) difference between implanted and planned positions was 9 ± 5 mm for the aggregate seed population. No significant systematic directional displacements were observed for this whole population. However, for individual patients, systematic displacements were observed, implying that intrapatient offsets occur during the procedure. Mean displacements for seeds in the different anatomic areas were not found to be significantly different from the mean for the entire seed population. However, small directional trends were observed within the anatomy, potentially indicating some bias in the delivery. Despite observed differences between the planned and implanted seed positions, the median (range) V{sub 90} for the 20 patients was 97% (66%-100%), and acceptable dosimetry was achieved for critical structures. Conclusions: No significant trends or systematic errors were observed in the placement of seeds in PBSI, including seeds implanted directly into the seroma. Recorded seed displacements may be related to intrapatient setup adjustments. Despite observed seed displacements, acceptable postimplant dosimetry was achieved.« less

Agamermis unka (Mermithidae) Parasitism of Nilaparvata lugens in Rice Fields in Korea

PubMed Central

Choo, Ho Yul; Kaya, Harry K.; Kim, Jeong Boo

1989-01-01

The mermithid Agamermis unka, a parasite of the brown planthopper (BPH), was found in many rice paddies in Gyeongnam Province, Korea. Nematode parasitism of adult BPH varied from year to year, reaching as high as 50% in paddies not treated with an insecticide. Parasitism was lower in insecticide-treated paddies. Generally, mermithid parasitism was higher in BPH adults collected from the lower part (19%) compared with adults collected from the upper part (8%) of the rice plant and in brachypterous (57%) compared with macropterous forms (8%). No difference in parasitism between first (54%) and second (57%) generation was observed. PMID:19287605

Detection of fumonisin producing Fusarium verticillioides in paddy (Oryza sativa L.) using polymerase chain reaction (PCR)

PubMed Central

Maheshwar, P.K.; Moharram, S. Ahmed; Janardhana, G.R.

2009-01-01

The study reports the occurrence of fumonisin producing Fusarium verticillioides in 90 samples of stored paddy (Oryza sativa L.) collected from different geographical regions of Karnataka, India. Fumonisin producing F. verticillioides was identified based on micromorphological characteristics and PCR using two sets of primers. One set of primers was F. verticillioides species specific, which selectively amplified the intergenic space region of rDNA. The other set of primers was specific to fumonisin producing F. verticillioides. Eight paddy samples were positive for F. verticillioides. Eleven isolates obtained from these samples were capable of producing fumonisin. PMID:24031332

Tier 1 Rice Model for Estimating Pesticide Concentrations in Rice Paddies

EPA Science Inventory

The Tier 1 Rice Model estimates screening level aquatic concentrations of pesticides in rice paddies. It is a simple pesticide soil:water partitioning model with default values for water volume, soil mass, and organic carbon. Pesticide degradation is not considered in the mode...

How the Air Force Should Stay Engaged in Computer Vision Technology Development

DTIC Science & Technology

2007-04-01

present individuals. The survey 29 Paddy Comyn, "Sensing Forward to a Driverless Future," The Irish...34 Military Embedded Systems (2006). Comyn, Paddy. "Sensing Forward to a Driverless Future." The Irish Times 21 February 2007. Dakley, Norman C. The

Biological research by optically pumped far infrared lasers

NASA Astrophysics Data System (ADS)

Zhengyu, Mi

1989-05-01

The FIR breeding for paddy rice, black bean and wheat, the chlorophyll mutation of paddy rice induced by optically pumped FIR laser, etc., are presented. The results of SDS electrophoresis analysis of soluble proteins of Drosophita melanrgaster irradiated by optically pumped FIR laser are described and discussed.

In vitro sterilization technique on embryo of black Toraja rice

NASA Astrophysics Data System (ADS)

Haring, F.; Riadi, M.; Rafiuddin; Sjahril, R.; Muchlis, A. R.

2018-05-01

Toraja black rice has a high anthocyanin content, a water-soluble pigments, with antioxidant activity. Toraja black rice has a variety of seeds colour in one panicles such as full black (the outside and inside the rice), medium black (the outside and slightly inside rice) and a little black (only the outside of rice). Embryo culture in vitro is one way to grow plants in sterile conditions. The presence of contamination and the death of the embryo require in vitro embryo culture. The sterilization technique is a very important first step to eliminate contamination and the death of embryos. This research aims to determine the right material composition for sterilization of black rice’s embryo. The experiment was done by growing black rice on half strength MS media with the treatment of three method of sterilization, i.e.: S1 (70% alcohol for 5 minutes, 3% and 2% Chlorox each for 10 minutes,), S2 (70% alcohol for 3 minutes, 2% Clorox for 10 minutes) and S3 (70% alcohol for 3 minutes and 1% Clorox for 15 minutes). The materials used are rice seedlings that have been cut in two and opened the pericarp of paddy grain, leaving a piece of rice that has a complete embryo. The best sterilization for Toraja black rice embryo culture was using the S3 composition. Best germination was seen on the seeds with full and medium black color.

Elevated CO2 facilitates C and N accumulation in a rice paddy ecosystem.

PubMed

Guo, Jia; Zhang, Mingqian; Wang, Xiaowen; Zhang, Weijian

2015-03-01

Elevated CO2 can stimulate wetland carbon (C) and nitrogen (N) exports through gaseous and dissolved pathways, however, the consequent influences on the C and N pools are still not fully known. Therefore, we set up a free-air CO2 enrichment experiment in a paddy field in Eastern China. After five year fumigation, we studied C and N in the plant-water-soil system. The results showed: (1) elevated CO2 stimulated rice aboveground biomass and N accumulations by 19.1% and 12.5%, respectively. (2) Elevated CO2 significantly increased paddy soil TOC and TN contents by 12.5% and 15.5%, respectively in the 0-15 cm layer, and 22.7% and 26.0% in the 15-30 cm soil layer. (3) Averaged across the rice growing period, elevated CO2 greatly increased TOC and TN contents in the surface water by 7.6% and 11.4%, respectively. (4) The TOC/TN ratio and natural δ15N value in the surface soil showed a decreasing trend under elevated CO2. The above results indicate that elevated CO2 can benefit C and N accumulation in paddy fields. Given the similarity between the paddies and natural wetlands, our results also suggest a great potential for long-term C and N accumulation in natural wetlands under future climate patterns. Copyright © 2015. Published by Elsevier B.V.

A paddy eco-ditch and wetland system to reduce non-point source pollution from rice-based production system while maintaining water use efficiency.

PubMed

Xiong, Yujiang; Peng, Shizhang; Luo, Yufeng; Xu, Junzeng; Yang, Shihong

2015-03-01

Non-point source (NPS) pollution from agricultural drainage has aroused widespread concerns throughout the world due to its contribution to eutrophication of water bodies. To remove nitrogen (N) and phosphorus (P) from agricultural drainage in situ, a Paddy Eco-ditch and Wetland System (PEDWS) was designed and built based on the characteristics of the irrigated rice district. A 2-year (2012-2013) field experiment was conducted to evaluate the performance of this system in Gaoyou Irrigation District in Eastern China. The results showed that the reduction in water input in paddy field of the PEDWS enabled the maintenance of high rice yield; it significantly increased irrigation water productivity (WPI), gross water productivity (WPG), and evapotranspiration water productivity (WPET) by 109.2, 67.1, and 17.6%, respectively. The PEDWS dramatically decreased N and P losses from paddy field. Compared with conventional irrigation and drainage system (CIDS), the amount of drainage water from PEDWS was significantly reduced by 56.2%, the total nitrogen (TN) concentration in drainage was reduced by 42.6%, and thus the TN and total phosphorus (TP) losses were reduced by 87.8 and 70.4%. PEDWS is technologically feasible and applicable to treat nutrient losses from paddy fields in situ and can be used in similar areas.

Aging well: methanotrophic potential and community structure along a paddy soil chronosequence of 2000 years.

NASA Astrophysics Data System (ADS)

Ho, Adrian; Frenzel, Peter

2010-05-01

Given that rice paddies are anthropogenic methane sources and the inevitable need to increase rice production to sustain human population growth, it is pertinent to identify the effects of long term agriculture on the selection of methanotrophs. Methanotrophs play a crucial role in mitigating methane emission from rice paddies. Therefore, we analyzed the methanotroph community along a chronosequence of paddy soils from China covering recently reclaimed sites to paddies under permanent agriculture since 2000 years (Cheng et al., 2009; doi:10.1016/j.geoderma.2009.03.016). Maximum potential methane oxidation rate (PMOR) increased monotonically with age. Our results also showed that long-term agriculture imposes a selection pressure on different groups of methanotrophs. In contrast to younger soils, type Ib methanotrophs were observed to multiply in correspondence with increasing PMOR in ancient soils, while other groups showed a relatively stable community composition as revealed by pmoA-based fingerprints (T-RFLP) and quantitative PCR. Cloning and sequencing the pmoA (a key gene in methane oxidation), the soils were found to harbour known and putative methanotrophs, ammonium-oxidizing bacteria, and interestingly, sequences affiliated to Crenothrix, a methane oxidizer with an unusual pmoA (Stoecker et al., 2006; doi:10.1073/pnas.0506361103). In summary, long-term agriculture shapes the community and allows for an elevated level of potential methane oxidation.

Microbial electricity generation in rice paddy fields: recent advances and perspectives in rhizosphere microbial fuel cells.

PubMed

Kouzuma, Atsushi; Kaku, Nobuo; Watanabe, Kazuya

2014-12-01

Microbial fuel cells (MFCs) are devices that use living microbes for the conversion of organic matter into electricity. MFC systems can be applied to the generation of electricity at water/sediment interfaces in the environment, such as bay areas, wetlands, and rice paddy fields. Using these systems, electricity generation in paddy fields as high as ∼80 mW m(-2) (based on the projected anode area) has been demonstrated, and evidence suggests that rhizosphere microbes preferentially utilize organic exudates from rice roots for generating electricity. Phylogenetic and metagenomic analyses have been conducted to identify the microbial species and catabolic pathways that are involved in the conversion of root exudates into electricity, suggesting the importance of syntrophic interactions. In parallel, pot cultures of rice and other aquatic plants have been used for rhizosphere MFC experiments under controlled laboratory conditions. The findings from these studies have demonstrated the potential of electricity generation for mitigating methane emission from the rhizosphere. Notably, however, the presence of large amounts of organics in the rhizosphere drastically reduces the effect of electricity generation on methane production. Further studies are necessary to evaluate the potential of these systems for mitigating methane emission from rice paddy fields. We suggest that paddy-field MFCs represent a promising approach for harvesting latent energy of the natural world.

Assessment of the air-soil partitioning of polycyclic aromatic hydrocarbons in a paddy field using a modified fugacity sampler.

PubMed

Wang, Yan; Luo, Chunling; Wang, Shaorui; Liu, Junwen; Pan, Suhong; Li, Jun; Ming, Lili; Zhang, Gan; Li, Xiangdong

2015-01-06

Rice, one of the most widely cultivated crops, has received great attention in contaminant uptake from soil and air, especially for the special approaches used for its cultivation. The dry-wet alternation method can influence the air-soil partitioning of semivolatile organic compounds (SVOCs) in the paddy ecosystem. Here, we modified a fugacity sampler to investigate the air-surface in situ partitioning of ubiquitous polycyclic aromatic hydrocarbons (PAHs) at different growth stages in a suburban paddy field in South China. The canopy of rice can form a closed space, which acts like a chamber that can force the air under the canopy to equilibrate with the field surface. When we compared the fugacities calculated using a fugacity model of the partition coefficients to the measured fugacities, we observed similar trends in the variation, but significantly different values between different growing stages, especially during the flooding stages. However, the measured and calculated fugacity fractions were comparable when uncertainties in our calculations were considered, with the exception of the high molecular weight (HMW) PAHs. The measured fugacity fractions suggested that the HMW PAHs were also closed to equilibrium between the paddy field and atmosphere. The modified fugacity sampler provided a novel way of accurately determining the in situ air-soil partitioning of SVOCs in a wet paddy field.

Influence of the nonexchangeable potassium of mica on radiocesium uptake by paddy rice.

PubMed

Eguchi, Tetsuya; Ohta, Takeshi; Ishikawa, Tetsuya; Matsunami, Hisaya; Takahashi, Yoshihiko; Kubo, Katashi; Yamaguchi, Noriko; Kihou, Nobuharu; Shinano, Takuro

2015-09-01

A pot cultivation experiment was conducted to elucidate the influence of the nonexchangeable potassium (K) of mica on radiocesium ((137)Cs) uptake by paddy rice (Oryza sativa L. cv. Koshihikari), and to evaluate the potential of mica application as a countermeasure to reduce radiocesium transfer from soil to paddy rice. The increase in the exchangeable K concentrations of soils, measured before planting, due to mica (muscovite, biotite, and phlogopite) application was negligible. However, in trioctahedral mica (biotite and phlogopite)-treated soil, the release of nonexchangeable K from the mica interlayer maintained the soil-solution K at a higher level during the growing season in comparison to the control, and consequently decreased the (137)Cs transfer factor for brown rice (TF). The sodium tetraphenylboron (TPB)-extractable K concentration of the soils, measured before planting, was strongly negatively correlated with the TF, whereas the exchangeable K concentration of the soils, also measured before planting, was not correlated with the TF. Therefore, we conclude that TPB-extractable K is more reliable than exchangeable K as a basis of fertilizer recommendations for radiocesium-contaminated paddy fields. Phlogopite-treated soils exhibited higher TPB-extractable K concentrations and lower TF values than biotite-treated soils. We thus conclude that phlogopite application is an effective countermeasure to reduce radiocesium uptake in paddy rice. Copyright © 2015 Elsevier Ltd. All rights reserved.

Self-seeding ring optical parametric oscillator

DOEpatents

Smith, Arlee V [Albuquerque, NM; Armstrong, Darrell J [Albuquerque, NM

2005-12-27

An optical parametric oscillator apparatus utilizing self-seeding with an external nanosecond-duration pump source to generate a seed pulse resulting in increased conversion efficiency. An optical parametric oscillator with a ring configuration are combined with a pump that injection seeds the optical parametric oscillator with a nanosecond duration, mJ pulse in the reverse direction as the main pulse. A retroreflecting means outside the cavity injects the seed pulse back into the cavity in the direction of the main pulse to seed the main pulse, resulting in higher conversion efficiency.

Recent direct seeding trials in the pine region

Treesearch

H.A. Fowells; G.H. Schubert

1951-01-01

Direct seeding is a highly desirable method of regeneration. It is more economical and more flexible in both time and place than the planting of trees. In California, however, direct seeding generally has been an ineffective method of regeneration. Early trials by the Forest Service with broadcast sowing and spot sowing invariably failed to produce an adequate stand of...

Dynamics of dense direct-seeded stands of southern pines

Treesearch

J.C.G. Goelz

2006-01-01

Direct seeding of southern pines is an effective method of artificial regeneration, producing extremely dense stands when survival exceeds expectations. Long-term studies of dense direct-seeded stands provide ideal data for exploring development of stands as they approach the limit of maximum stand density. I present data from seven studies with ages of stands ranging...

Role of cosubstrate and bioaccessibility played in the enhanced anaerobic biodegradation of organochlorine pesticides (OCPs) in a paddy soil by nitrate and methyl-β-cyclodextrin amendments.

PubMed

Ye, Mao; Sun, Mingming; Ni, Ni; Chen, Yinwen; Liu, Zongtang; Gu, Chengang; Bian, Yongrong; Hu, Feng; Li, Huixin; Kengara, Fredrick Orori; Jiang, Xin

2014-01-01

The present study was conducted to investigate the anaerobic biodegradation potential of biostimulation by nitrate (KNO3) and methyl-β-cyclodextrin (MCD) addition on an aged organochlorine pesticide (OCP)-contaminated paddy soil. After 180 days of incubation, total OCP biodegradation was highest in soil receiving the addition of nitrate and MCD simultaneously and then followed by nitrate addition, MCD addition, and control. The highest biodegradation of chlordanes, hexachlorocyclohexanes, endosulfans, and total OCPs was 74.3, 63.5, 51.2, and 65.1%, respectively. Meanwhile, MCD addition significantly increased OCP bioaccessibility (p < 0.05) evaluated by Tenax TA extraction and a three-compartment model method. Moreover, the addition of nitrate and MCD also obtained the highest values of soil microbial activities, including soil microbial biomass carbon and nitrogen, ATP production, denitrifying bacteria count, and nitrate reductase activity. Such similar trend between OCP biodegradation and soil-denitrifying activities suggests a close relationship between OCP biodegradation and N cycling and the indirect/direct involvement of soil microorganisms, especially denitrifying microorganisms in the anaerobic biodegradation of OCPs.

A successful direct seeding of sugar pine.

Treesearch

William I. Stein

1957-01-01

In southwestern Oregon, the first pilot-scale direct seeding of sugar pine produced a well-stocked stand of seedlings on a 45-acre tract. Control of seed-eating rodents was accomplished by spot-baiting with 1080-treated wheat before seeding, by spot-baiting with thallium sulfate-treated wheat in late December, and by broadcast-baiting with 1080-treated wheat in early...

Direct seeding of lemon-gum eucalyptus, redwood, and brushbox in Hawaii

Treesearch

Gerald A. Waiters

1970-01-01

Direct seeding has economic and silvicultural advantages over planted seedlings. To see if three selected timber species could be direct-seeded, trials were held at Kulani Camp, island of Hawaii. After 1 year, lemon-gum eucalyptus had fair stocking and height growth, but redwood and brushbox had not progressed satisfactorily. Mulch had no real effect on either stocking...

Oleoresin Capsicum has Potential as a Rodent Repellent in Direct Sedding Longleaf Pine

Treesearch

James P. Barnett

1998-01-01

Direct seeding of southern pines has been a versatile and inexpensive alternative to planting on many reforestation sites across the South. Successful direct seeding has required that seeds be coated with thiram to repel birds, and with endrin to repel rodents. Endrin, which is extremely toxic, is no longer produced in the United States. Therefore, a substitute is...

Direct seeding trials of three major timber species in Hawaii

Treesearch

Gerald A. Waiters; Craig D. Whitesell

1971-01-01

Trials are underway to detemine the feasibility of direct seeding timber species to specific sites. Three major timber species were direct seeded on a moist, cindery, low-elevation site on the island of Hawaii. After 1 year, West Indies mahogany and monkey-god had acceptable stocking; stocking of lemon-gum eucalyptus was considered poor. All thee species made rapid...

Effects of rodent species, seed species, and predator cues on seed fate

NASA Astrophysics Data System (ADS)

Sivy, Kelly J.; Ostoja, Steven M.; Schupp, Eugene W.; Durham, Susan

2011-07-01

Seed selection, removal and subsequent management by granivorous animals is thought to be a complex interaction of factors including qualities of the seeds themselves (e.g., seed size, nutritional quality) and features of the local habitat (e.g. perceived predator risk). At the same time, differential seed selection and dispersal is thought to have profound effects on seed fate and potentially vegetation dynamics. In a feeding arena, we tested whether rodent species, seed species, and indirect and direct predation cues influence seed selection and handling behaviors (e.g., scatter hoarding versus larder hoarding) of two heteromyid rodents, Ord's kangaroo rat ( Dipodomys ordii) and the Great Basin pocket mouse ( Perognathus parvus). The indirect cue was shrub cover, a feature of the environment. Direct cues, presented individually, were (1) control, (2) coyote ( Canis latrans) vocalization, (3) coyote scent, (4) red fox ( Vulpes vulpes) scent, or (5) short-eared owl ( Asio flammeus) vocalization. We offered seeds of three sizes: two native grasses, Indian ricegrass ( Achnatherum hymenoides) and bluebunch wheatgrass ( Pseudoroegneria spicata), and the non-native cereal rye ( Secale cereale), each in separate trays. Kangaroo rats preferentially harvested Indian ricegrass while pocket mice predominately harvested Indian ricegrass and cereal rye. Pocket mice were more likely to scatter hoard preferred seeds, whereas kangaroo rats mostly consumed and/or larder hoarded preferred seeds. No predator cue significantly affected seed preferences. However, both species altered seed handling behavior in response to direct predation cues by leaving more seeds available in the seed pool, though they responded to different predator cues. If these results translate to natural dynamics on the landscape, the two rodents are expected to have different impacts on seed survival and plant recruitment via their different seed selection and seed handling behaviors.

Effects of rodent species, seed species, and predator cues on seed fate

USGS Publications Warehouse

Sivy, Kelly J.; Ostoja, Steven M.; Schupp, Eugene W.; Durham, Susan

2011-01-01

Seed selection, removal and subsequent management by granivorous animals is thought to be a complex interaction of factors including qualities of the seeds themselves (e.g., seed size, nutritional quality) and features of the local habitat (e.g. perceived predator risk). At the same time, differential seed selection and dispersal is thought to have profound effects on seed fate and potentially vegetation dynamics. In a feeding arena, we tested whether rodent species, seed species, and indirect and direct predation cues influence seed selection and handling behaviors (e.g., scatter hoarding versus larder hoarding) of two heteromyid rodents, Ord's kangaroo rat (Dipodomys ordii) and the Great Basin pocket mouse (Perognathus parvus). The indirect cue was shrub cover, a feature of the environment. Direct cues, presented individually, were (1) control, (2) coyote (Canis latrans) vocalization, (3) coyote scent, (4) red fox (Vulpes vulpes) scent, or (5) short-eared owl (Asio flammeus) vocalization. We offered seeds of three sizes: two native grasses, Indian ricegrass (Achnatherum hymenoides) and bluebunch wheatgrass (Pseudoroegneria spicata), and the non-native cereal rye (Secale cereale), each in separate trays. Kangaroo rats preferentially harvested Indian ricegrass while pocket mice predominately harvested Indian ricegrass and cereal rye. Pocket mice were more likely to scatter hoard preferred seeds, whereas kangaroo rats mostly consumed and/or larder hoarded preferred seeds. No predator cue significantly affected seed preferences. However, both species altered seed handling behavior in response to direct predation cues by leaving more seeds available in the seed pool, though they responded to different predator cues. If these results translate to natural dynamics on the landscape, the two rodents are expected to have different impacts on seed survival and plant recruitment via their different seed selection and seed handling behaviors.

Water balance of rice plots under three different water treatments: monitoring activity and experimental results

NASA Astrophysics Data System (ADS)

Chiaradia, Enrico Antonio; Romani, Marco; Facchi, Arianna; Gharsallah, Olfa; Cesari de Maria, Sandra; Ferrari, Daniele; Masseroni, Daniele; Rienzner, Michele; Battista Bischetti, Gian; Gandolfi, Claudio

2014-05-01

In the agricultural seasons 2012 and 2013, a broad monitoring activity was carried out at the Rice Research Centre of Ente Nazionale Risi (CRR-ENR) located in Castello d'Agogna (PV, Italy) with the purpose of comparing the water balance components of paddy rice (Gladio cv.) under different water regimes and assessing the possibility of reducing the high water inputs related to the conventional practice of continuous submergence. The experiments were laid out in six plots of about 20 m x 80 m each, with two replicates for each of the following water regimes: i) continuous flooding with wet-seeded rice (FLD), ii) continuous flooding from around the 3-leaf stage with dry-seeded rice (3L-FLD), and iii) surface irrigation every 7-10 days with dry-seeded rice (IRR). One out of the two replicates of each treatment was instrumented with: water inflow and outflow meters, set of piezometers, set of tensiometers and multi-sensor moisture probes. Moreover, an eddy covariance station was installed on the bund between the treatments FLD and IRR. Data were automatically recorded and sent by a wireless connection to a PC, so as to be remotely controlled thanks to the development of a Java interface. Furthermore, periodic measurements of crop biometric parameters (LAI, crop height and rooting depth) were performed in both 2012 and 2013 (11 and 14 campaigns respectively). Cumulative water balance components from dry-seeding (3L-FLD and IRR), or flooding (FLD), to harvest were calculated for each plot by either measurements (i.e. rainfall, irrigation and surface drainage) or estimations (i.e. difference in the field water storage, evaporation from both the soil and the water surface and transpiration), whereas the sum of percolation and capillary rise (i.e. the 'net percolation') was obtained as the residual term of the water balance. Incidentally, indices of water application efficiency (evapotranspiration over net water input) and water productivity (grain production over net water input) were calculated for each treatment. The outcomes show that the water application efficiencies of all treatments were higher in 2013 than in 2012 (by 23%, 25% and 4% for FLD, 3L-FLD, and IRR respectively). These results could be ascribed to the higher groundwater level observed in 2013 (about 10-15 cm closer to the soil surface), likely due to the conversion of the field beyond the monitored plots from soybean to flooded rice. Moreover, a small increase of the water application efficiency of 3L-FLD was found if compared to FLD (3% on average), while the water application efficiency of IRR was, on average, higher by 67% compared to FLD. The good performance of IRR is related to lower percolation rates and a relevant contribution of capillary rise due to the shallow groundwater table maintained by the continuous submergence of the surrounding paddy fields. The performed experiment highlighted that significant improvement in the water use efficiency at the field scale can be achieved. However, a widespread adoption of water regimes different from continuous flooding should be carefully evaluated by a larger-scale approach since a consequent drop in the groundwater table depth could have repercussions on the potential gains themselves.

Persistence behaviour of thiamethoxam and lambda cyhalothrin in transplanted paddy.

PubMed

Barik, Suhrid Ranjan; Ganguly, Pritam; Kunda, Samir Kumar; Kole, Ramen Kumar; Bhattacharyya, Anjan

2010-10-01

A field study was conducted in Pre-Kharif season 2007 on paddy to determine the persistence of thiamethoxam (12.6%) and lambda cyhalothrin (9.4%) [in a 'Readymix' formulation Alika 247 ZC], following the application of 33 g. a.i. ha⁻¹ (T₁) and 66 g. a.i. ha⁻¹ (T₂). Spraying of insecticide was done during milking stage of the crop (63 days after transplantation). Thiamethoxam and lambda cyhalothrin residues were estimated by HPLC and GLC respectively. The half-life values were 5.2-5.8 and 4.8 days for thiamethoxam and lambda cyhalothrin respectively. No residue was detected in the harvested paddy, straw, grain, and soil samples.

Twenty Years of Prescribed Burning Influence the Development of Direct-Seeded Longleaf Pine on a Wet Pine Site in Louisiana

Treesearch

James D. Haywood; Harold E. Grelen

2000-01-01

Prescribed burning treatments were applied over a 20 yr period in a commonly randomized field study to determine the effects of various fire regimes on vegetation in a direct seeded standof longleaf pine (Pinus palustris Mill.). Seeding was done in November 1968. The study area was broadcast-burned about 16 months after seeding. The initial...

Quantitation of Indoleacetic Acid Conjugates in Bean Seeds by Direct Tissue Hydrolysis 1

PubMed Central

Bialek, Krystyna; Cohen, Jerry D.

1989-01-01

Gas chromatography-selected ion monitoring-mass spectral analysis using [13C6]indole-3-acetic acid (IAA) as an internal standard provides an effective means for quantitation of IAA liberated during direct strong basic hydrolysis of bean (Phaseolus vulgaris L.) seed powder, provided that extra precautions are undertaken to exclude oxygen from the reaction vial. Direct seed powder hydrolysis revealed that the major portion of amide IAA conjugates in bean seeds are not extractable by aqueous acetone, the solvent used commonly for IAA conjugate extraction from seeds and other plant tissues. Strong basic hydrolysis of plant tissue can be used to provide new information on IAA content. Images Figure 1 PMID:16666783

CADMIUM SOLUBILITY IN PADDY SOILS: EFFECTS OF SOIL OXIDATION, METAL SULFIDES AND COMPETITIVE IONS.

EPA Science Inventory

Cadmium (Cd) is a non-essential element for human nutrition and is an agricultural soil contaminant. Cadmium solubility in paddy soils affects Cd accumulation in the grain of rice. This is a human health risk, exacerbated by the fact that rice grains are deficient in iron (Fe) an...

Dissipation of clomazone, imazapyr and imazapic herbicides in paddy water under two rice flood management regimes

USDA-ARS?s Scientific Manuscript database

Pesticides are frequently detected in rivers, lakes and groundwater sources in regions where rice is cultivated in Brazil. The transport of these compounds to water sources is strongly related to the irrigation system adopted in paddy fields. However, information on the dissipation of clomazone, ima...

Soil Physicochemical and Biological Properties of Paddy-Upland Rotation: A Review

PubMed Central

Lv, Teng-Fei; Chen, Yong; Westby, Anthony P.; Ren, Wan-Jun

2014-01-01

Paddy-upland rotation is an unavoidable cropping system for Asia to meet the increasing demand for food. The reduction in grain yields has increased the research interest on the soil properties of rice-based cropping systems. Paddy-upland rotation fields are unique from other wetland or upland soils, because they are associated with frequent cycling between wetting and drying under anaerobic and aerobic conditions; such rotations affect the soil C and N cycles, make the chemical speciation and biological effectiveness of soil nutrient elements varied with seasons, increase the diversity of soil organisms, and make the soil physical properties more difficult to analyze. Consequently, maintaining or improving soil quality at a desirable level has become a complicated issue. Therefore, fully understanding the soil characteristics of paddy-upland rotation is necessary for the sustainable development of the system. In this paper, we offer helpful insight into the effect of rice-upland combinations on the soil chemical, physical, and biological properties, which could provide guidance for reasonable cultivation management measures and contribute to the improvement of soil quality and crop yield. PMID:24995366

A Technique of Fuzzy C-Mean in Multiple Linear Regression Model toward Paddy Yield

NASA Astrophysics Data System (ADS)

Syazwan Wahab, Nur; Saifullah Rusiman, Mohd; Mohamad, Mahathir; Amira Azmi, Nur; Che Him, Norziha; Ghazali Kamardan, M.; Ali, Maselan

2018-04-01

In this paper, we propose a hybrid model which is a combination of multiple linear regression model and fuzzy c-means method. This research involved a relationship between 20 variates of the top soil that are analyzed prior to planting of paddy yields at standard fertilizer rates. Data used were from the multi-location trials for rice carried out by MARDI at major paddy granary in Peninsular Malaysia during the period from 2009 to 2012. Missing observations were estimated using mean estimation techniques. The data were analyzed using multiple linear regression model and a combination of multiple linear regression model and fuzzy c-means method. Analysis of normality and multicollinearity indicate that the data is normally scattered without multicollinearity among independent variables. Analysis of fuzzy c-means cluster the yield of paddy into two clusters before the multiple linear regression model can be used. The comparison between two method indicate that the hybrid of multiple linear regression model and fuzzy c-means method outperform the multiple linear regression model with lower value of mean square error.

Direct seeding woody species for restoration of bottomlands

USGS Publications Warehouse

Twedt, D.J.; Connor, Kristina F

2006-01-01

I direct seeded (broadcast) seeds of 39 species of trees and shrubs using an ATV-mounted rotary spreader to initiate restoration of bottomland forest on retired agricultural sites. Four sites were planted during February, 2000, and 13 additional sites were planted during April and May, 2001. After two growing seasons, stem density of direct-seeded species varied greatly among study plots (range = 0 to 888 stems/ha) but averaged only 110 stems/ha. I recommend that future efforts at direct seeding focus on seven shrub species (Amorpha fruticosa L., Cephalanthus occidentalis L., Cornus spp., Crataegus spp., Ilex decidua Walt., Morus rubra L., and Prunus spp.) and seven tree species (Celtis laevigata Willd., Diospyros virginiana L., Fraxinus spp., Gleditsia triacanthos L., Robinia pseudoacacia L., Taxodium distichum (L.) Rich, and Ulmus spp.) that successfully established in these trials.

Red Oak (Quercus rubra, L.) acron collection, nursery culture and direct seeding: A literature review

Treesearch

Daniel C. Dey

1995-01-01

The artificial regeneration of red oak by planting or direct seeding is an important method for restoring oak in ecosystems where it has been lost as a result of past management practices. Planting and direct seeding can also be used to supplement natural oak regeneration and to ensure that sufficient oak reproduction is in place when overstories are removed through...

Potential Contribution of Anammox to Nitrogen Loss from Paddy Soils in Southern China

PubMed Central

Yang, Xiao-Ru; Li, Hu; Nie, San-An; Su, Jian-Qiang; Weng, Bo-Sen; Zhu, Gui-Bing; Yao, Huai-Ying; Gilbert, Jack A.

2014-01-01

The anaerobic oxidation of ammonium (anammox) process has been observed in diverse terrestrial ecosystems, while the contribution of anammox to N2 production in paddy soils is not well documented. In this study, the anammox activity and the abundance and diversity of anammox bacteria were investigated to assess the anammox potential of 12 typical paddy soils collected in southern China. Anammox bacteria related to “Candidatus Brocadia” and “Candidatus Kuenenia” and two novel unidentified clusters were detected, with “Candidatus Brocadia” comprising 50% of the anammox population. The prevalence of the anammox was confirmed by the quantitative PCR results based on hydrazine synthase (hzsB) genes, which showed that the abundance ranged from 1.16 × 104 to 9.65 × 104 copies per gram of dry weight. The anammox rates measured by the isotope-pairing technique ranged from 0.27 to 5.25 nmol N per gram of soil per hour in these paddy soils, which contributed 0.6 to 15% to soil N2 production. It is estimated that a total loss of 2.50 × 106 Mg N per year is linked to anammox in the paddy fields in southern China, which implied that ca. 10% of the applied ammonia fertilizers is lost via the anammox process. Anammox activity was significantly correlated with the abundance of hzsB genes, soil nitrate concentration, and C/N ratio. Additionally, ammonia concentration and pH were found to be significantly correlated with the anammox bacterial structure. PMID:25416768

Quantitative analyses of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) large-subunit genes (cbbL) in typical paddy soils.

PubMed

Xiao, Ke-Qing; Bao, Peng; Bao, Qiong-Li; Jia, Yan; Huang, Fu-Yi; Su, Jian-Qiang; Zhu, Yong-Guan

2014-01-01

The Calvin cycle is known to be the major pathway for CO2 fixation, but our current understanding of its occurrence and importance in paddy soils is poor. In this study, the diversity of three ribulose-1,5-bisphosphate carboxylase/oxygenase large-subunit genes (cbbLG, cbbLR, cbbM) was investigated by clone library, T-RFLP, qPCR, and enzyme assay in five paddy soils in China. The cbbLG sequences revealed a relatively low level of diversity and were mostly related to the sequences of species from Thiobacillus. In contrast, highly diverse cbbLR and cbbM sequences were dispersed on the phylogenetic trees, and most of them were distantly related to known sequences, even forming separate clusters. Abundances of three cbbL genes ranged from 10(6) to 10(9) copies g(-1) soil, and cbbLR outnumbered cbbM and cbbLG in all soil samples, indicating that cbbLR may play a more important role than other two cbbL genes. Soil properties significantly influenced cbbL diversity in five paddy soils, of which clay content, C/N ratio, CEC, pH, and SOC correlated well with variations in microbial composition and abundance. In summary, this study provided a comparison of three cbbL genes, advancing our understanding of their role in carbon sequestration and nutrient turnover in the paddy soil. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Influence of heavy metals and PCBs pollution on the enzyme activity and microbial community of paddy soils around an e-waste recycling workshop.

PubMed

Tang, Xianjin; Hashmi, Muhammad Z; Long, Dongyan; Chen, Litao; Khan, Muhammad I; Shen, Chaofeng

2014-03-14

Due to the emerging environmental issues related to e-waste there is concern about the quality of paddy soils near e-waste workshops. The levels of heavy metals and PCBs and their influence on the enzyme activity and microbial community of paddy soils obtained from the immediate vicinity of an e-waste workshop were investigated in the present study. The results indicated that the heavy metal and PCB pollution did not differ significantly with an increase of the sampling point distances (5 to 30 m). The concentration of Cd (2.16 mg·kg-1) and Cu (69.2 mg·kg-1) were higher, and the PCB pollution was also serious, ranging from 4.9 to 21.6 μg·kg-1. The highest enzyme activity was found for urease compared to phosphatase and catalase, and a fluctuating trend in soil enzyme activity was observed in soils from different sampling sites. The microbial analysis revealed that there was no apparent correlation between the microbial community and the pollutants. However, a slight influence for soil microbial communities could be found based on DGGE, the Shannon index and PCA analysis. The present study suggests that the contamination stress of heavy metals and PCBs might have a slight influence on microbial activity in paddy soils. This study provides the baseline data for enzyme activities and microbial communities in paddy soil under the influence of mixed contamination.

Phosphorus content as a function of soil aggregate size and paddy cultivation in highly weathered soils.

PubMed

Li, Baozhen; Ge, Tida; Xiao, Heai; Zhu, Zhenke; Li, Yong; Shibistova, Olga; Liu, Shoulong; Wu, Jinshui; Inubushi, Kazuyuki; Guggenberger, Georg

2016-04-01

Red soils are the major land resource in subtropical and tropical areas and are characterized by low phosphorus (P) availability. To assess the availability of P for plants and the potential stability of P in soil, two pairs of subtropical red soil samples from a paddy field and an adjacent uncultivated upland were collected from Hunan Province, China. Analysis of total P and Olsen P and sequential extraction was used to determine the inorganic and organic P fractions in different aggregate size classes. Our results showed that the soil under paddy cultivation had lower proportions of small aggregates and higher proportions of large aggregates than those from the uncultivated upland soil. The portion of >2-mm-sized aggregates increased by 31 and 20 % at Taoyuan and Guiyang, respectively. The total P and Olsen P contents were 50-150 and 50-300 % higher, respectively, in the paddy soil than those in the upland soil. Higher inorganic and organic P fractions tended to be enriched in both the smallest and largest aggregate size classes compared to the middle size class (0.02-0.2 mm). Furthermore, the proportion of P fractions was higher in smaller aggregate sizes (<2 mm) than in the higher aggregate sizes (>2 mm). In conclusion, soils under paddy cultivation displayed improved soil aggregate structure, altered distribution patterns of P fractions in different aggregate size classes, and to some extent had enhanced labile P pools.

Influence of Heavy Metals and PCBs Pollution on the Enzyme Activity and Microbial Community of Paddy Soils around an E-Waste Recycling Workshop

PubMed Central

Tang, Xianjin; Hashmi, Muhammad Z.; Long, Dongyan; Chen, Litao; Khan, Muhammad I.; Shen, Chaofeng

2014-01-01

Due to the emerging environmental issues related to e-waste there is concern about the quality of paddy soils near e-waste workshops. The levels of heavy metals and PCBs and their influence on the enzyme activity and microbial community of paddy soils obtained from the immediate vicinity of an e-waste workshop were investigated in the present study. The results indicated that the heavy metal and PCB pollution did not differ significantly with an increase of the sampling point distances (5 to 30 m). The concentration of Cd (2.16 mg·kg−1) and Cu (69.2 mg·kg−1) were higher, and the PCB pollution was also serious, ranging from 4.9 to 21.6 μg·kg−1. The highest enzyme activity was found for urease compared to phosphatase and catalase, and a fluctuating trend in soil enzyme activity was observed in soils from different sampling sites. The microbial analysis revealed that there was no apparent correlation between the microbial community and the pollutants. However, a slight influence for soil microbial communities could be found based on DGGE, the Shannon index and PCA analysis. The present study suggests that the contamination stress of heavy metals and PCBs might have a slight influence on microbial activity in paddy soils. This study provides the baseline data for enzyme activities and microbial communities in paddy soil under the influence of mixed contamination. PMID:24637907

Generation of methane from paddy fields and cattle in India, and its reduction at source

NASA Astrophysics Data System (ADS)

Bandyopadhyay, T. K.; Goyal, P.; Singh, M. P.

Methane (CH4) is a saturated organic gas. About 500 Tg yr -1 methane is generated globally. It is evident that 70% of the total emission have anthropogenic sources. The paddy fields contribute a significant portion of the total methane generated. About 20% of the total methane is generated from the paddy fields. In India, methane efflux rate is negative to 49 mg m -2 hr -1. The mean CH4 flux from Indian paddy fields is calculated to be 4.0 Tgyr -1. Livestock, and in particular ruminants are one of the important sources of methane emission on a global scale. There are two sources of methane emission from live stock: (1) from digestive process of ruminants, (2) from animal wastes. The estimated value of methane emission from digestive process of ruminants in India accounts for 6.47 Tgyr -1, and animal wastes accounts for 1.60 Tgyr -1. Total generation of methane from animals in India is about 8.0 Tg yr -1 . In paddy fields the key of controlling methane emission lies in the control of irrigation water. The methane emission can be decreased drastically if the field is under dry conditions for a few days at the end of tillering. In the case of livestock, reduction of methane emission can be done by (1) increasing the intake of the animal, (2) modifying the composition of the diet, (3) eliminating protozoa in rumen, (4) improving fibre digestion efficiency and (5) inhibiting activity of methanogenic bacteria.

Discrepant responses of methane emissions to additions with different organic compound classes of rice straw in paddy soil.

PubMed

Tan, Wenbing; Yu, Hanxia; Huang, Caihong; Li, Dan; Zhang, Hui; Jia, Yufu; Wang, Guoan; Xi, Beidou

2018-07-15

Crop straw incorporation has become a prevailing agricultural practice that guarantees the food production and security. There is a significant body of work on the effects of straw incorporation on the methane (CH 4 ) emissions in paddy fields. However, it is unclear whether there are diverse links between CH 4 emission dynamics and incorporations of different organic compound classes of straw to paddy fields. In this study, soil incubations were conducted to assess the respective effect of incorporations of hydrolysable amino acid (HAA), dilute-acid extractable carbohydrate (DAC), lipid and acid-insoluble organic matter (AIOM) fractions of rice straw on the CH 4 emission in paddy soil. It is revealed that incorporations of HAA and DAC fractions exert the greatest intensities to stimulate the CH 4 emissions, which mainly takes place in the early period of incubation; on contrary, the incorporation of lipid fraction exerts the lowest intensity and mainly takes place in the late period. The pattern of CH 4 emission after incorporation of AIOM fraction occurs peaks both in the early and late periods of incubation. Our findings highlight that the time of occurrence and intensity of effects of rice straw incorporation on CH 4 emissions vary significantly depending on the different organic compound classes of rice straw, which may be key to proposing a promising management strategy for mitigating CH 4 emissions in paddy fields in the context of straw incorporation. Copyright © 2018 Elsevier B.V. All rights reserved.

H2-Producing Bacterial Community during Rice Straw Decomposition in Paddy Field Soil: Estimation by an Analysis of [FeFe]-Hydrogenase Gene Transcripts.

PubMed

Baba, Ryuko; Asakawa, Susumu; Watanabe, Takeshi

2016-09-29

The transcription patterns of [FeFe]-hydrogenase genes (hydA), which encode the enzymes responsible for H2 production, were investigated during rice straw decomposition in paddy soil using molecular biological techniques. Paddy soil amended with and without rice straw was incubated under anoxic conditions. RNA was extracted from the soil, and three clone libraries of hydA were constructed using RNAs obtained from samples in the initial phase of rice straw decomposition (day 1 with rice straw), methanogenic phase of rice straw decomposition (day 14 with rice straw), and under a non-amended condition (day 14 without rice straw). hydA genes related to Proteobacteria, Firmicutes, Bacteroidetes, Chloroflexi, and Thermotogae were mainly transcribed in paddy soil samples; however, their proportions markedly differed among the libraries. Deltaproteobacteria-related hydA genes were predominantly transcribed on day 1 with rice straw, while various types of hydA genes related to several phyla were transcribed on day 14 with rice straw. Although the diversity of transcribed hydA was significantly higher in the library on day 14 with rice straw than the other two libraries, the composition of hydA transcripts in the library was similar to that in the library on day 14 without rice straw. These results indicate that the composition of active H2 producers and/or H2 metabolic patterns dynamically change during rice straw decomposition in paddy soil.

Influence of dissolved organic matter on sorption and desorption of MCPA in ferralsol.

PubMed

Wu, Dongming; Yun, Yonghuan; Jiang, Lei; Wu, Chunyuan

2018-03-01

MCPA (4-chloro-2-methylphenoxyacetic acid) is an acidic herbicide, widely used in paddy fields. The presence of dissolved organic matter (DOM) modifies the sorption-desorption of herbicides in soils. In this study, effects of DOM on sorption- desorption of MCPA were tested using three typical ferralsol soil types from China: rhodic ferralsol, haplic ferralsol and paddy soil. DOM preparations were extracted from the paddy soil (DOM P ), from a compost mixture of cassava stems with chicken manure (DOM C ), and from rice straw (DOM R ). Sorption-desorption of MCPA in the tested soil types was shown to follow pseudo first-order kinetics, and the calculated isotherm data fitted well with a Freundlich equilibrium model in the range of the studied concentrations. MCPA was weakly sorbed by the soils, producing low Freundlich coefficient values (K f ) (0.854 to 4.237). The presence of DOM reduced the K f whereby DOM C had the strongest and DOM R the weakest effect. Presence of DOM also promoted MCPA desorption from the soils, again with DOM C having the strongest effect and DOM R the weakest. DOM coating changed the soil particle surface, as demonstrated by electron microscopy, and DOM also directly interacted with MCPA, as shown by Fourier-transform infrared spectroscopy. The experimental data were interpreted to suggest a competing sorption of DOM to ferralsol and an increased solubility of MCPA in the presence of DOM. The results indicate that the environmental risk of MCPA leaching to groundwater and surface flow is increased by presence of DOM, for instance as a result of organic fertilizer use. Copyright © 2017. Published by Elsevier B.V.

[Effects of irrigation of untreated livestock farm wastewater on accumulation and vertical mig- ration of nitrogen and phosphorus in paddy soil].

PubMed

Zhang, Ming-kui; Ahmed Elgodah; Bao, Chen-yan

2014-12-01

Although a series of process techniques for treating wastewater from livestock and poultry breeding have been developed in China and overseas, it is still common in China's rural areas for utilization of the untreated wastewater to irrigate farmland directly because of economic reasons. The impact of untreated wastewater irrigation on accumulation and vertical migration of nitrogen and phosphorus in paddy soil is concerned. Consequently, four representative paddy fields with different histories of livestock farm wastewater irrigation (0, 4, 7, 13 years) were selected for collecting profile soil samples to study the effects of long-term irrigation of untreated livestock farm wastewater on various forms of nitrogen and phosphorus in the soils at different vertical depths. As compared with control field without any irrigation of wastewater, long-term irrigation of untreated livestock farm wastewater significantly increased the accumulation of N and P in the soils with increasing the irrigation year, and the increment of total P in the soil was greater than that of total N. Total P content in surface soil from fields with 4, 7, and 13 years irrigation was increased by 43.6%, 95.2%, and 148.4%, while total N increased by 7.6%, 16.9%, and 28.4%, respectively. Different forms of soil N were increased in order of NH4+ -N, NO3- -N > acid hydrolyzable N > non-acid hydrolyzable N, and soil available P changed much more than total P. Long-term irrigation of untreated livestock farm wastewater could promote vertical migration of soil nitrogen and phosphorus, and increase the pollution risk for groundwater.

Molecular detection of pathogenic leptospiral protein encoding gene (lipL32) in environmental aquatic biofilms.

PubMed

Vinod Kumar, K; Lall, C; Vimal Raj, R; Vedhagiri, K; Vijayachari, P

2016-04-01

Leptospirosis is a zoonotic disease often encountered during post-monsoon season due to exposure with contaminated water. Leptospires have long been regarded as solitary organisms that persist in soil and aquatic environments. Here, the presence of leptospires in the aquatic biofilm exposed in the paddy field, sewers and stagnant rain water was demonstrated. Biofilm samples from paddy field water, submerged paddy leaves, sewers and stagnant rain waters from urban and rural areas were collected. Total genomic DNA was extracted and pathogenic leptospiral specific gene amplification was carried out to determine the spatial distribution of the bacteria. The degree of pathogenic Leptospira in biofilms from paddy field surface water, submerged leaf, were 33·3% and 27·2% respectively, whereas in rural and urban area, the sampling sites such as stagnant rain water, domestic sewer and collective sewers showed 11·1%, 13% and 16·6% with leptospires respectively. Higher proportion of pathogenic Leptospira in aquatic ecosystems, such as paddy field, could be one of the main factors for the occurrence of disease, more among the agricultural workers. This study would help to identify various survival strategies of leptospires in the environment and thus disease transmission. Little is known regarding the mechanisms by which pathogenic leptospires persist in aqueous environment, outside the mammalian host. In this view this is the first report of the distribution of Leptospira in environmental biofilm such as sewers and paddy leaf surfaces. This ability of pathogenic Leptospira to survive in aquatic ecosystems especially in biofilms could be one of the main factors which facilitate its survival in the environment, and thus disease transmission among the risk groups, such as sewage and agriculture worker. This study will encourage researchers in the field to consider biofilm as an important factor, when detecting leptospires in environment. © 2015 The Society for Applied Microbiology.

Observation of methane fluxes using eddy covariance technique and relaxed eddy accumulation techniques simultaneously over rice paddies in Taiwan

NASA Astrophysics Data System (ADS)

Tang, M.; Tsai, J.; Tsuang, B.; Feng, P.; Kuo, P.

2012-12-01

In the past decades, more and more attention was given to the increase of atmospheric methane concentration from the scientific community. Methane is one of greenhouse gases with a global warming potential 21 times greater than carbon dioxide on a 100-year horizon. Rice paddy fields were considered as a major source for methane and so far there are few studies where the eddy covariance (EC) technique has been used to measure methane fluxes from rice paddy fields, especially in Asia. Therefore, in this study we used EC technique and relaxed eddy accumulation (REA) method simultaneously to observe the methane fluxes over rice paddy, fertilized with pig manure, in Taiwan from 22th February to 5th June in 2012. A suit of Micrometeorologial variables and water table depth were measured in conjunction with the fluxes. The results showed that the rice paddy field was source of methane during most of the study period and the observed methane fluxes ranged between - 0.5 and 13 μg m-2 s-1. and the maximum values usually occurred in the afternoon. A significant methane emission was observed in the first one and a half month after transplanting. Comparison of daily methane fluxes measured by EC and REA showed generally good agreement between both methods with a coefficient of determination of 0.81, although the magnitude of methane fluxes measured by REA were slightly lower than those by EC. During the continuous flooded period, the methane fluxes can be depicted well by a function of soil temperature with an exponential form. Sudden pulses of methane fluxes were observed when drained for the removal of obstruction which hindered the methane diffuse from the soil to the atmosphere. During fallow period between growth periods, the paddy fields was a sink of methane where the methane uptake was about 0.5μg m-2 s-1 around noon.

Spatial distribution and temporal variability of arsenic in irrigated rice fields in Bangladesh. 2. Paddy soil.

PubMed

Dittmar, Jessica; Voegelin, Andreas; Roberts, Linda C; Hug, Stephan J; Saha, Ganesh C; Ali, M Ashraf; Badruzzaman, A Borhan M; Kretzschmar, Ruben

2007-09-01

Arsenic-rich groundwater from shallow tube wells is widely used for the irrigation of boro rice in Bangladesh and West Bengal. In the long term this may lead to the accumulation of As in paddy soils and potentially have adverse effects on rice yield and quality. In the companion article in this issue, we have shown that As input into paddy fields with irrigation water is laterally heterogeneous. To assess the potential for As accumulation in soil, we investigated the lateral and vertical distribution of As in rice field soils near Sreenagar (Munshiganj, Bangladesh) and its changes over a 1 year cycle of irrigation and monsoon flooding. At the study site, 18 paddy fields are irrigated with water from a shallow tube well containing 397 +/- 7 microg L(-1) As. The analysis of soil samples collected before irrigation in December 2004 showed that soil As concentrations in paddy fields did not depend on the length of the irrigation channel between well and field inlet. Within individual fields, however, soil As contents decreased with increasing distance to the water inlet, leading to highly variable topsoil As contents (11-35 mg kg(-1), 0-10 cm). Soil As contents after irrigation (May 2005) showed that most As input occurred close to the water inlet and that most As was retained in the top few centimeters of soil. After monsoon flooding (December 2005), topsoil As contents were again close to levels measured before irrigation. Thus, As input during irrigation was at least partly counteracted by As mobilization during monsoon flooding. However, the persisting lateral As distribution suggests net arsenic accumulation over the past 15 years. More pronounced As accumulation may occur in regions with several rice crops per year, less intense monsoon flooding, or different irrigation schemes. The high lateral and vertical heterogeneity of soil As contents must be taken into account in future studies related to As accumulation in paddy soils and potential As transfer into rice.

Stabilization by hydrophobic protection as a molecular mechanism for organic carbon sequestration in maize-amended rice paddy soils.

PubMed

Song, X Y; Spaccini, R; Pan, G; Piccolo, A

2013-08-01

The hydrophobic components of soil organic matter (SOM) are reckoned to play an important role in the stabilization of soil organic carbon (SOC). The contribution of hydrophobic substances to SOC sequestration was evaluated in four different paddy soils in the South of China, following a 6-month incubation experiment with maize straw amendments. Soil samples included: a well developed paddy soil (TP) derived from clayey lacustrine deposits in the Tai Lake plain of Jiangsu; an acid clayey paddy soil (RP) derived from red earth in the rolling red soil area of Jiangxi; a weakly developed neutral paddy soil (PP) formed on Jurassic purple shale from Chongq; and a calcic Fluvisol (MS) derived from riverine sediments from a wetland along the Yangtze valley of Anhui, China. The SOC molecular composition after 30 and 180 days of incubation, was determined by off-line thermochemolysis followed by gas chromatography-mass spectrometry analysis. Lignin, lipids and carbohydrates were the predominant thermochemolysis products released from the treated soils. A selective preservation of hydrophobic OM, including lignin and lipids, was shown in maize amended soils with prolonged incubation. The decomposition of lignin and lipids was significantly slower in the TP and RP soils characterized by a larger content of extractable iron oxyhydrates (Fed) and lower pH. The overall increase in hydrophobic substances in maize incubated samples was correlated, positively, with total content of clay and Fed, and, negatively, with soil pH. Moreover, yields of both lignin and lipid components showed a significant relationship with SOC increase after incubation. These findings showed that the larger the lipid and lignin content of SOM, the greater was the stability of SOC, thereby suggesting that OM hydrophobic components may have an essential role in controlling the processes of OC sequestration in paddy soils of South China. Copyright © 2013 Elsevier B.V. All rights reserved.

Wind-dispersed seed deposition patterns and seedling recruitment of Artemisia halodendron in a moving sandy land.

PubMed

Li, Feng-Rui; Wang, Tao; Zhang, Ai-Sheng; Zhao, Li-Ya; Kang, Ling-Fen; Chen, Wen

2005-07-01

Artemisia halodendron is a native sub-shrub that occurs mainly in moving and semi-fixed sandy lands in Inner Mongolia, China. Information on the spatial patterns of wind-dispersed seed deposition and seedling recruitment of A. halodendron inhabiting moving sandy lands is very limited. The aim of this study was to examine wind-dispersed seed deposition patterns and post-dispersal recruitment of A. halodendron seedlings. * The spatial patterns of wind-dispersed seed deposition and seedling recruitment of A. halodendron were examined by investigating the numbers of deposited seeds, emerged and surviving seedlings using sampling points at a range of distances from the parent plant in eight compass directions for two consecutive growing seasons. * Wind-dispersed seed deposition showed considerable variation between directions and years. Wind transported A. halodendron seeds only a few meters away from the parent plant in all eight directions. Seedling emergence and establishment also showed between-direction and between-year variability, but the spatial pattern of seedling distribution differed from that of seed deposition. Only a very small fraction (<1 %) of the deposited seeds emerged in the field and survived for long enough to be included in our seedling censuses at the end of the growing season. * The spatial variation in wind speed and frequency strongly affects the pattern of seed deposition, although the variation in seed deposition does not determine the spatial pattern of seedling recruitment. Seeds of A. halodendron are not dispersed very well by wind. The low probability of recruitment success for A. halodendron seedlings suggests that this species does not rely on seedling recruitment for its persistence and maintenance of population.

Comparison of Different Methods for Separation of Haploid Embryo Induced through Irradiated Pollen and Their Economic Analysis in Melon (Cucumis melo var. inodorus)

PubMed Central

Baktemur, Gökhan; Taşkın, Hatıra; Büyükalaca, Saadet

2013-01-01

Irradiated pollen technique is the most successful haploidization technique within Cucurbitaceae. After harvesting of fruits pollinated with irradiated pollen, classical method called as “inspecting the seeds one by one” is used to find haploid embryos in the seeds. In this study, different methods were used to extract the embryos more easily, quickly, economically, and effectively. “Inspecting the seeds one by one” was used as control treatment. Other four methods tested were “sowing seeds direct nutrient media,” “inspecting seeds in the light source,” “floating seeds on liquid media,” and “floating seeds on liquid media after surface sterilization.” Y2 and Y3 melon genotypes selected from the third backcross population of Yuva were used as plant material. Results of this study show that there is no statistically significant difference among methods “inspecting the seeds one by one,” “sowing seeds direct CP nutrient media,” and “inspecting seeds in the light source,” although the average number of embryos per fruit is slightly different. No embryo production was obtained from liquid culture because of infection. When considered together with labor costs and time required for embryo rescue, the best methods were “sowing seeds directly in the CP nutrient media“ and ”inspecting seeds in the light source.” PMID:23818825

[Effects of marshland reclamation on evapotranspiration in the Sanjiang Plain].

PubMed

Jia, Zhi-jun; Zhang, Wen; Huang, Yao; Zhao, Xiao-song; Song, Chang-chun

2010-04-01

Extensive reclamation of marshland into cropland has had tremendous effects on the ecological environment in the Sanjiang Plain. Observations over marshland, rice paddy and soybean field were made with eddy covariance measuring systems from May to October in 2005, 2006 and 2007. The objective of this study was to identify the effects of the conversion of marshland to cropland on evapotranspiration in the Sanjiang Plain. The results showed that the diurnal variation curves of latent heat flux were single peaked in marshland, rice paddy and soybean field. The daily maximum latent heat flux increased by 14%-130% in rice paddy in the three measuring years, however, in soybean field, it increased by 3%-77% in 2006 but decreased by 25%-40% in 2005 and 2007 by comparison with that in marshland. This difference was due to the change of leaf area index when marshland was reclaimed into cropland. Seasonal change of latent heat flux was identical for the three land use types. Daily averaged latent heat flux of rice paddy, from May to October, showed 38%-53% increase compared with that of marshland, which resulted from the increase in net radiation and leaf area index. When marshland was reclaimed into soybean field, the variation of daily averaged latent heat flux depended primarily on precipitation. Precipitation was the main factor that controlled evapotranspiration over soybean field which was usually in condition of soil water deficit. Drought caused 11%-17% decrease of daily averaged latent heat flux over soybean field in 2005 and 2007, while sufficient precipitation caused 22% increase in 2006, comparing to marshland. Similarly, during the growing season from June to September, total evapotranspiration of rice paddy increased by 24%-51% compared with that of marshland, and the total evapotranspiration of soybean field decreased by 19%-23% in 2005 and 2007 and increased by 19% in 2006. It is concluded that the evapotranspiration changes significantly when the marshland was reclaimed into rice paddy or soybean field in the Sanjiang Plain. Compared to marshland, the evapotranspiration is higher in rice paddy and soybean filed with sufficient precipitation, while lower in soybean field under drought. These changes are found to be highly related to the variations of net radiation, leaf area index and precipitation.

Backscattering and vegetation water content response of paddy crop at C-band using RISAT-1 satellite data

NASA Astrophysics Data System (ADS)

Kumar, Pradeep; Prasad, Rajendra; Choudhary, Arti; Gupta, Dileep Kumar; Narayan Mishra, Varun; Srivastava, Prashant K.

2016-04-01

The study about the temporal behaviour of vegetation water content (VWC) is essential for monitoring the growth of a crop to improve agricultural production. In agriculture, VWC could possibly provide information that can be used to infer water stress for irrigation decisions, vegetation health conditions, aid in yield estimation and assessment of drought conditions (Penuelas et al., 1993). The VWC is an important parameter for soil moisture retrieval in microwave remote sensing (Srivastava et al., 2014). In the present study, the backscattering and VWC response of paddy crop has been investigated using medium resolution (MRS) radar imaging satellite-1 (RISAT-1) synthetic aperture radar (SAR) data in Varanasi, India. The VWC of paddy crop was measured at its five different growth stages started from 15 July 2013 to 23 October 2013 from the transplanting to maturity stage during Kharif season. The whole life of paddy crop was divided into three different major growth stages like vegetative stage, reproductive stage and ripening stage. During vegetative stage, the backscattering coefficients were found increasing behaviour until the leaves became large and dense due to major contribution of stems and the interaction between the stems and water underneath the paddy crop. During reproductive stage, the backscattering coefficients were found to increase slowly due to random scattering by vertical leaves. The increase in the size of leaves cause to cover most of the spaces between plants resulted to quench the contributions from the stems and the water underneath. At the maturity stage, the backscattering showed its decreasing behaviour. The VWC of paddy crop was found increasing up to vegetative to reproductive stages (28 September 2013) and then started decreasing during the ripening (maturity) stage. Similar behaviour was obtained between backscattering coefficients and VWC that showed an increasing trend from vegetative to reproductive stage and then lowering down at ripening stage at HH- and HV- polarizations. It is concluded that HH- polarized backscattering coefficients using RISAT-1 data are more sensitive in comparison to HV- polarized backscattering coefficients. The C-band, RISAT-1 backscattering coefficients may be useful for the retrieval of VWC of paddy crop to monitor its growth stages. Keywords: SAR, C-band, dual polarimetric, RISAT-1, VWC, paddy References: Penuelas, J., Filella, I., Biel, C., Serrano, L., & Save, R. (1993). The reflectance at the 950-970 mm region as an indicator of plant water status. International Journal of Remote Sensing, 14:1887-1905. Srivastava , P. K., Han, D., Rico-Ramirez, M. A., O'Neill, P., Islam, T., & Gupta, M. (2014). Assessment of SMOS soil moisture retrieval parameters using tau-omega algorithms for soil moisture deficit estimation. Journal of Hydrology 519:574-587

Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide

NASA Astrophysics Data System (ADS)

Praphulla Chandra, Boggarapu; Sinha, Vinayak

2016-04-01

In the North West Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October-November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r ≥ 0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62 ± 0.18 ppb), benzene (2.51 ± 0.28 ppb), toluene (3.72 ± 0.41 ppb), C8-aromatics (2.88 ± 0.30 ppb), C9-aromatics (1.55 ± 0.19 ppb) and CO (552 ± 113 ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97 ± 0.17 ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6 ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of benzene and ensure compliance with the NAAQS. Calculations of excessive lifetime cancer risk due to benzene amount to 25 and 10 per million inhabitants for children and adults, respectively, exceeding the USEPA threshold of 1 per million inhabitants. Annual exposure to isocyanic acid was close to 1 ppb, the concentration considered to be sufficient to enhance risks for cardiovascular diseases and cataracts. This study makes a case for urgent mitigation of post-harvest paddy residue fires as the unknown synergistic effect of multi-pollutant exposure due to emissions from this anthropogenic source may be posing grave health risks to the population of the N.W. IGP. This work has been published very recently and the citation to the complete work is: B.P. Chandra, Vinayak Sinha, Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide, Environment International, Volume 88, March 2016, Pages 187-197, ISSN 0160-4120, http://dx.doi.org/10.1016/j.envint.2015.12.025.

Direct seeding in northern forest types

Treesearch

Ralph H. Griffin

1977-01-01

Two direct-seeding experiments were established to determine the effect of time of seeding (spring 1962 versus fall 1962), type of seedbed (prepared versus unprepared), and species (red pine (Pinus resinosa Ait.) versus white spruce (Picea glauca (Moench) Voss)) upon the success attained in the reforestation of a pine-barren site...

Urbanization dramatically altered the water balances of a paddy field dominated basin in southern China

Treesearch

L. Hao; G. Sun; Y. Liu; J. Wan; M. Qin; H. Qian; C. Liu; R. John; P. Fan; J. Chen

2015-01-01

Rice paddy fields provide important ecosystem services (e.g., food production, water retention, carbon sequestration) to a large population globally. However, these benefits are declining as a result of rapid environmental and socioeconomic transformations characterized by population growth, urbanization, and climate change in many Asian countries. This case study...

Toward optimal soil organic carbon sequestration with effects of agricultural management practices and climate change in Tai-Lake paddy soils of China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Liming; Zhuang, Qianlai; He, Yujie

Understanding the impacts of climate change and agricultural management practices on soil organic carbon (SOC) dynamics is critical for implementing optimal farming practices and maintaining agricultural productivity. This study examines the influence of climate and agricultural management on carbon sequestration potentials in Tai-Lake Paddy soils of China using the DeNitrification-DeComposition (DNDC) model, with a high-resolution soil database (1:50,000). Model simulations considered the effects of no tillage, increasing manure application, increasing/decreasing of N-fertilizer application and crop residues, water management, and climatic shifts in temperature and precipitation. We found that the carbon sequestration potential for the 2.32 Mha paddy soils of themore » Tai-Lake region varied from 4.71 to 44.31 Tg C during the period 2001-2019, with an annual average SOC changes ranged from 107 to 1005 kg C ha -1 yr -1. The sequestration potential significantly increased with increasing application of N-fertilizer, manure, conservation tillage, and crop residues. To increase soil C sequestration in this region, no-tillage and increasing of crop residue return to soils and manure application are recommended. Our analysis of climate impacts on SOC sequestration suggests that the rice paddies in this region will continue to be a carbon sink under future warming conditions. In addition, because the region’s annual precipitation (>1200 mm) is high, we also recommend reducing irrigation water use for these rice paddies to conserve freshwater in the Tai-Lake region.« less

Effect of Functionalised and Non-Functionalised Carbon Nanotubes-Urea Fertilizer on the Growth of Paddy.

PubMed

Yatim, Norazlina Mohamad; Shaaban, Azizah; Dimin, Mohd Fairuz; Yusof, Faridah; Razak, Jeefferie Abd

2018-03-01

The roles of multi-walled carbon nanotubes (MWNTs) and functionalised multiwalled carbon nanotubes (fMWNTs) in enhancing the efficacy of urea fertilizer (UF) as plant nutrition for local MR219 paddy variety was investigated. The MWNTs and fMWNTs were grafted onto UF to produce UF-MWNTs fertilizer with three different conditions, coded as FMU1 (0.6 wt. % fMWNTs), FMU2 (0.1 wt. % fMWNTs) and MU (0.6 wt. % MWNTs. The batches of MR219 paddy were systematically grown in accordance to the general practice performed by the Malaysian Agricultural Research and Development Institute (MARDI). The procedure was conducted using a pot under exposure to natural light at three different fertilization times; after a certain number of days of sowing (DAS) at 14, 35 and 55 days. Interestingly, it was found that the crop growth of plants treated with FMU1 and FMU2 significantly increased by 22.6% and 38.5% compared to plants with MU addition. Also, paddy treated with FMU1 produced 21.4% higher number of panicles and 35% more grain yield than MU while paddy treated with FMU2 gave 28.6% more number of panicles and 36% higher grain yield than MU, which implies the advantage of fMWNTs over MWNTs to be combined with UF as plant nutrition. The chemical composition and morphology of UF-MWNTs fertilizers which is further characterised by FTiR and FESEM confirmed the successful and homogeneous grafting of UF onto the fMWNTs.

Purification of contaminated paddy fields by clean water irrigation over two decades.

PubMed

Tai, Yiping; Lu, Huanping; Li, Zhian; Zhuang, Ping; Zou, Bi; Xia, Hanping; Wang, Faming; Wang, Gang; Duan, Jun; Zhang, Jianxia

2013-10-01

Paddy fields near a mining site in north part of Guangdong Province, PR China, were severely contaminated by heavy metals as a result of wastewater irrigation from the tailing pond. The following clean water irrigation for 2 decades produced marked rinsing effect, especially on Pb and Zn. Paddy fields continuously irrigated with wastewater ever since mining started (50 years) had 1,050.0 mg kg−1 of Pb and 810.3 mg kg−1 of Zn for upper 20 cm soil, in comparison with 215.9 mg kg−1 of Pb and 525.4 mg kg−1 of Zn, respectively, with clean water irrigation for 20 years. Rinsing effect mainly occurred to a depth of upper 40 cm, of which the soil contained highest metals. Copper and Cd in the farmlands were also reduced due to clean water irrigation. Higher availability of Pb might partly account for more Pb transferred from the tailing pond to the farmland and also more Pb removal from the farmland as a result of clean water irrigation. Neither rice in the paddy field nor dense weeds in the uncultivated field largely took up the metals. However, they might contribute to activate metals differently, leading to a different purification extent. Rotation of rice and weed reduced metal retention in the farmland soil, in comparison with sole rice growth. Harvesting of rice grain (and partially rice stalk) only contributed small fraction of total amount of removed metal. In summary, heavy metal in paddy field resulting from irrigation of mining wastewater could be largely removed by clean water irrigation for sufficient time.

Monitoring of selected pesticides residue levels in water samples of paddy fields and removal of cypermethrin and chlorpyrifos residues from water using rice bran.

PubMed

Bhattacharjee, Shubhra; Fakhruddin, A N M; Chowdhury, M A Z; Rahman, M A; Alam, M K

2012-08-01

Consumption of pesticides associated foods increased in recent decades in Bangladesh. Most of the pesticides come from paddy, as rice is the main food items here and about 70 % pesticides are used only on paddy fields. Water samples of paddy fields and Kaliganga River of Manikganj district were analyzed to provide base line data on cypermethrin, chlorpyrifos and diazinon residue by using high performance liquid chromatography. Levels of Cypermethrin, chlorpyrifos and diazinon detected in the paddy field water samples were (0.605 ± 0.011 μg/L), (0.06 ± 0.001 μg/L) and (0.039 ± 0.002 μg/L), respectively. 0.11 ± 0.003 μg/L of cypermethrin and 0.012 ± 0.0006 μg/L of chlorpyrifos were also identified in the water samples of Kaligonga River. Diazinon residue was not detected in the river water samples. The detected concentrations of pesticide residues in the river water were below the accepted maximum residue limit (MRL) value of drinking water (0.1 μg/l) adopted by the FAO/WHO Codex Alimentarius Commission. Cypermethrin and chlorpyrifos were chosen for decontamination through rice bran, as it was found in river water. Two gm rice bran could easily decontaminated 95.6 % and 96.4 % of cypermethrin and chlorpyrifos. The result of this study showed that pesticide residue was detected in water samples were below the MRLs value, which can easily be decontaminated through absorption of rice bran.

Polar and non-polar organic aerosols from large-scale agricultural-waste burning emissions in Northern India: Implications to organic mass-to-organic carbon ratio.

PubMed

Rajput, Prashant; Sarin, M M

2014-05-01

This study focuses on characteristics of organic aerosols (polar and non-polar) and total organic mass-to-organic carbon ratio (OM/OC) from post-harvest agricultural-waste (paddy- and wheat-residue) burning emissions in Northern India. Aerosol samples from an upwind location (Patiala: 30.2°N, 76.3°E) in the Indo-Gangetic Plain were analyzed for non-polar and polar fractions of organic carbon (OC1 and OC2) and their respective mass (OM1 and OM2). On average, polar organic aerosols (OM2) contribute nearly 85% of the total organic mass (OM) from the paddy- and wheat-residue burning emissions. The water-soluble-OC (WSOC) to OC2 ratio, within the analytical uncertainty, is close to 1 from both paddy- and wheat-residue burning emissions. However, temporal variability and relatively low WSOC/OC2 ratio (Av: 0.67±0.06) is attributed to high moisture content and poor combustion efficiency during paddy-residue burning, indicating significant contribution (∼30%) of aromatic carbon to OC2. The OM/OC ratio for non-polar (OM1/OC1∼1.2) and polar organic aerosols (OM2/OC2∼2.2), hitherto unknown for open agricultural-waste burning emissions, is documented in this study. The total OM/OC ratio is nearly identical, 1.9±0.2 and 1.8±0.2, from paddy- and wheat-residue burning emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of red mud based passivator on the transformation of Cd fraction in acidic Cd-polluted paddy soil and Cd absorption in rice.

PubMed

Li, Hui; Liu, Yan; Zhou, Yaoyu; Zhang, Jiachao; Mao, Qiming; Yang, Yuan; Huang, Hongli; Liu, Zhaohui; Peng, Qinghui; Luo, Lin

2018-06-04

Highly effective, economical, and replicable ways of Cd-polluted paddy field remediation (in situ) are urgently needed. In this work, a yearlong field experiment (both early and late rice) was conducted to investigate the effects of red mud based passivator [red mud, diatomite, and lime (5:3:2)] on remediation of an acidic Cd-polluted paddy field in Hunan Province. Compared with the control, the addition of red mud based passivator in the early and late rice reduced Cd concentration in each part of the rice plant (with the most significant decrease rate of 59.18% and 72.11% for brown rice in the early rice and late rice seasons respectively). The effect of Cd reduction in the rice plant was persistent in the next growing season. The addition of red mud based passivator also reduced the exchangeable fraction of Cd in the soil and converted the exchangeable fraction into other unavailable fractions. This study demonstrated that the pH in acidic soil increased after the application of red mud based passivator. Furthermore, red mud based passivator had no effect on the concentrations of Olsen-K, Alkaline-N, Olsen-P in the soil, but increased rice grain yield. Overall, the results of this study indicated that the red mud based passivator at 0.6 kg m -2 could be a recommendation for Cd-polluted acidic paddy soil stabilization, and it would be a suitable method for remediation of Cd-polluted acidic paddy soil. Copyright © 2018 Elsevier B.V. All rights reserved.

Mitigating effects of ex situ application of rice straw on CH4 and N2O emissions from paddy-upland coexisting system

PubMed Central

Wang, Wei; Wu, Xiaohong; Chen, Anlei; Xie, Xiaoli; Wang, Yunqiu; Yin, Chunmei

2016-01-01

The in situ application of rice straw enhances CH4 emissions by a large margin. The ex situ application of rice straw in uplands, however, may mitigate total global warming potential (GWP) of CH4 and N2O emissions from paddy-upland coexisting systems. To evaluate the efficiency of this practice, two field trials were conducted in rice-rice-fallow and maize-rape cropping systems, respectively. Year-round measurements of CH4 and N2O emissions were conducted to evaluate the system-scaled GWP. The results showed that CH4 accounted for more than 98% of GWP in paddy. Straw removal from paddy decreased 44.7% (302.1 kg ha−1 yr−1) of CH4 emissions and 51.2% (0.31 kg ha−1 yr−1) of N2O emissions, thus decreased 44.8% (7693 kg CO2-eqv ha−1 yr−1) of annual GWP. N2O accounted for almost 100% of GWP in upland. Straw application in upland had insignificant effects on CH4 and N2O emissions, which increased GWP only by 91 kg CO2-eqv ha−1 yr−1. So, the transfer of straw from paddy to upland could decrease GWP by 7602 kg CO2-eqv ha−1 yr−1. Moreover, straw retention during late rice season contributed to 88.2% of annual GWP increment. It is recommended to transfer early rice straw to upland considering GWP mitigation, nutrient recycling and labor cost. PMID:27869209

Influence of fertilisation regimes on a nosZ-containing denitrifying community in a rice paddy soil.

PubMed

Chen, Zhe; Hou, Haijun; Zheng, Yan; Qin, Hongling; Zhu, Yijun; Wu, Jinshui; Wei, Wenxue

2012-03-30

Denitrification is a microbial process that has received considerable attention during the past decade since it can result in losses of added nitrogen fertilisers from agricultural soils. Paddy soil has been known to have strong denitrifying activity, but the denitrifying microorganisms responsible for fertilisers in paddy soil are not well known. The objective of this study was to explore the impacts of 17-year application of inorganic and organic fertiliser (rice straw) on the abundance and composition of a nosZ-denitrifier community in paddy soil. Soil samples were collected from CK plots (no fertiliser), N (nitrogen fertiliser), NPK (nitrogen, phosphorus and potassium fertilisers) and NPK + OM (NPK plus organic matter). The nitrous oxide reductase gene (nosZ) community composition was analysed using terminal restriction fragment length polymorphism, and the abundance was determined by quantitative PCR. Both the largest abundance of nosZ-denitrifier and the highest potential denitrifying activity (PDA) occurred in the NPK + OM treatment with about four times higher than that in the CK and two times higher than that in the N and NPK treatments (no significant difference). Denitrifying community composition differed significantly among fertilisation treatments except for the comparison between CK and N treatments. Of the measured abiotic factors, total organic carbon was significantly correlated with the observed differences in community composition and abundance (P < 0.01 by Monte Carlo permutation). This study shows that the addition of different fertilisers affects the size and composition of the nosZ-denitrifier community in paddy soil. Copyright © 2011 Society of Chemical Industry.

Mitigating effects of ex situ application of rice straw on CH4 and N2O emissions from paddy-upland coexisting system

NASA Astrophysics Data System (ADS)

Wang, Wei; Wu, Xiaohong; Chen, Anlei; Xie, Xiaoli; Wang, Yunqiu; Yin, Chunmei

2016-11-01

The in situ application of rice straw enhances CH4 emissions by a large margin. The ex situ application of rice straw in uplands, however, may mitigate total global warming potential (GWP) of CH4 and N2O emissions from paddy-upland coexisting systems. To evaluate the efficiency of this practice, two field trials were conducted in rice-rice-fallow and maize-rape cropping systems, respectively. Year-round measurements of CH4 and N2O emissions were conducted to evaluate the system-scaled GWP. The results showed that CH4 accounted for more than 98% of GWP in paddy. Straw removal from paddy decreased 44.7% (302.1 kg ha-1 yr-1) of CH4 emissions and 51.2% (0.31 kg ha-1 yr-1) of N2O emissions, thus decreased 44.8% (7693 kg CO2-eqv ha-1 yr-1) of annual GWP. N2O accounted for almost 100% of GWP in upland. Straw application in upland had insignificant effects on CH4 and N2O emissions, which increased GWP only by 91 kg CO2-eqv ha-1 yr-1. So, the transfer of straw from paddy to upland could decrease GWP by 7602 kg CO2-eqv ha-1 yr-1. Moreover, straw retention during late rice season contributed to 88.2% of annual GWP increment. It is recommended to transfer early rice straw to upland considering GWP mitigation, nutrient recycling and labor cost.

Characterization of contamination, source and degradation of petroleum between upland and paddy fields based on geochemical characteristics and phospholipid fatty acids.

PubMed

Zhang, Juan; Wang, Renqing; Du, Xiaoming; Li, Fasheng; Dai, Jiulan

2012-01-01

To evaluate contamination caused by petroleum, surface soil samples were collected from both upland and paddy fields along the irrigation canals in the Hunpu wastewater irrigation region in northeast China. N-alkanes, terpanes, steranes, and phospholipid fatty acids (PLFA) in the surface soil samples were analyzed. The aliphatic hydrocarbon concentration was highest in the samples obtained from the upland field near an operational oil well; it was lowest at I-3P where wastewater irrigation promoted the downward movement of hydrocarbons. The Hunpu region was found contaminated by heavy petroleum from oxic lacustrine fresh water or marine deltaic source rocks. Geochemical parameters also indicated significantly heavier contamination and degradation in the upland fields compared with the paddy fields. Principal component analysis based on PLFA showed various microbial communities between petroleum contaminated upland and paddy fields. Gram-negative bacteria indicated by 15:0, 3OH 12:0, and 16:1(9) were significantly higher in the paddy fields, whereas Gram-positive bacteria indicated by i16:0 and 18:1(9)c were significantly higher in the upland fields (p < 0.05). These PLFAs were related to petroleum contamination. Poly-unsaturated PLFA (18:2omega6, 9; indicative of hydrocarbon-degrading bacteria and fungi) was also significantly elevated in the upland fields. This paper recommends more sensitive indicators of contamination and degradation of petroleum in soil. The results also provide guidelines on soil pollution control and remediation in the Hunpu region and other similar regions.

Effect of Functionalised and Non-Functionalised Carbon Nanotubes-Urea Fertilizer on the Growth of Paddy

PubMed Central

Yatim, Norazlina Mohamad; Shaaban, Azizah; Dimin, Mohd Fairuz; Yusof, Faridah; Razak, Jeefferie Abd

2018-01-01

The roles of multi-walled carbon nanotubes (MWNTs) and functionalised multiwalled carbon nanotubes (fMWNTs) in enhancing the efficacy of urea fertilizer (UF) as plant nutrition for local MR219 paddy variety was investigated. The MWNTs and fMWNTs were grafted onto UF to produce UF-MWNTs fertilizer with three different conditions, coded as FMU1 (0.6 wt. % fMWNTs), FMU2 (0.1 wt. % fMWNTs) and MU (0.6 wt. % MWNTs. The batches of MR219 paddy were systematically grown in accordance to the general practice performed by the Malaysian Agricultural Research and Development Institute (MARDI). The procedure was conducted using a pot under exposure to natural light at three different fertilization times; after a certain number of days of sowing (DAS) at 14, 35 and 55 days. Interestingly, it was found that the crop growth of plants treated with FMU1 and FMU2 significantly increased by 22.6% and 38.5% compared to plants with MU addition. Also, paddy treated with FMU1 produced 21.4% higher number of panicles and 35% more grain yield than MU while paddy treated with FMU2 gave 28.6% more number of panicles and 36% higher grain yield than MU, which implies the advantage of fMWNTs over MWNTs to be combined with UF as plant nutrition. The chemical composition and morphology of UF-MWNTs fertilizers which is further characterised by FTiR and FESEM confirmed the successful and homogeneous grafting of UF onto the fMWNTs. PMID:29644013

Interference of allelopathic rice with paddy weeds at the root level.

PubMed

Yang, X-F; Kong, C-H

2017-07-01

Despite increasing knowledge of the involvement of allelopathy in negative interactions among plants, relatively little is known about its action at the root level. This study aims to enhance understanding of interactions of roots between a crop and associated weeds via allelopathy. Based on a series of experiments with window rhizoboxes and root segregation methods, we examined root placement patterns and root interactions between allelopathic rice and major paddy weeds Cyperus difformis, Echinochloa crus-galli, Eclipta prostrata, Leptochloa chinensis and Oryza sativa (weedy rice). Allelopathic rice inhibited growth of paddy weed roots more than shoots regardless of species. Furthermore, allelopathic rice significantly reduced total root length, total root area, maximum root width and maximum root depth of paddy weeds, while the weeds adjusted horizontal and vertical placement of their roots in response to the presence of allelopathic rice. With the exception of O. sativa (weedy rice), root growth of weeds avoided expanding towards allelopathic rice. Compared with root contact, root segregation significantly increased inhibition of E. crus-galli, E. prostrata and L. chinensis through an increase in rice allelochemicals. In particular, their root exudates induced production of rice allelochemicals. However, similar results were not observed in C. difformis and O. sativa (weedy rice) with either root segregation or root exudate application. The results demonstrate that allelopathic rice interferes with paddy weeds by altering root placement patterns and root interactions. This is the first case of a root behavioural strategy in crop-weed allelopathic interaction. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

NASA Astrophysics Data System (ADS)

Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

2016-06-01

Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

Toxic assessment of the leachates of paddy soils and river sediments from e-waste dismantling sites to microalga, Pseudokirchneriella subcapitata.

PubMed

Nie, Xiangping; Fan, Canpeng; Wang, Zhaohui; Su, Tian; Liu, Xinyu; An, Taicheng

2015-01-01

The potential adverse effects of e-waste recycling activity on environment are getting increasing concern. In this work, a model alga, Pseudokirchneriella subcapitata, was employed to assess the toxic effects of the leachates of paddy soils and river sediments collected from e-waste dismantling sites. Chemical analysis of the paddy soils and river sediments and their leachates were carried out and the growth rate, chlorophyll a fluorescence and anti-oxidative systems of the alga were measured. Results showed that two leachates decreased the amount of PSII active reaction centers and affected photosynthesis performance, interfered with chlorophyll synthesis and inhibited algal growth. Some chemical pollutants in the sediments and soils such as polybrominated diphenyl ethers (PBDEs) and metals derived from e-waste recycling activity may impose oxidative stress on algae and affect the activity of anti-oxidative enzymes such as GST, SOD, CAT and APX. The leachates of both river sediments and paddy soils are potentially toxic to the primary producers, P. subcapitata and the leachate from sediments was more deleterious than that from soils. Copyright © 2014 Elsevier Inc. All rights reserved.

Avian diversity and feeding guilds in a secondary forest, an oil palm plantation and a paddy field in riparian areas of the kerian river basin, perak, malaysia.

PubMed

Azman, Nur Munira; Latip, Nurul Salmi Abdul; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md; Shafie, Nur Juliani; Khairuddin, Nurul Liyana

2011-12-01

The diversity and the feeding guilds of birds in three different habitats (secondary forest, oil palm plantation and paddy field) were investigated in riparian areas of the Kerian River Basin (KRB), Perak, Malaysia. Point-count observation and mist-netting methods were used to determine bird diversity and abundance. A total of 132 species of birds from 46 families were recorded in the 3 habitats. Species diversity, measured by Shannon's diversity index, was 3.561, 3.183 and 1.042 in the secondary forest, the paddy field and the oil palm plantation, respectively. The vegetation diversity and the habitat structure were important determinants of the number of bird species occurring in an area. The relative abundance of the insectivore, insectivore-frugivore and frugivore guilds was greater in the forest than in the monoculture plantation. In contrast, the relative abundance of the carnivore, granivore and omnivore guilds was higher in the plantation. The results of the study show that the conversion of forest to either oil palm plantation or paddy fields produced a decline in bird diversity and changes in the distribution of bird feeding guilds.

Avian Diversity and Feeding Guilds in a Secondary Forest, an Oil Palm Plantation and a Paddy Field in Riparian Areas of the Kerian River Basin, Perak, Malaysia

PubMed Central

Azman, Nur Munira; Latip, Nurul Salmi Abdul; Sah, Shahrul Anuar Mohd; Akil, Mohd Abdul Muin Md; Shafie, Nur Juliani; Khairuddin, Nurul Liyana

2011-01-01

The diversity and the feeding guilds of birds in three different habitats (secondary forest, oil palm plantation and paddy field) were investigated in riparian areas of the Kerian River Basin (KRB), Perak, Malaysia. Point-count observation and mist-netting methods were used to determine bird diversity and abundance. A total of 132 species of birds from 46 families were recorded in the 3 habitats. Species diversity, measured by Shannon’s diversity index, was 3.561, 3.183 and 1.042 in the secondary forest, the paddy field and the oil palm plantation, respectively. The vegetation diversity and the habitat structure were important determinants of the number of bird species occurring in an area. The relative abundance of the insectivore, insectivore-frugivore and frugivore guilds was greater in the forest than in the monoculture plantation. In contrast, the relative abundance of the carnivore, granivore and omnivore guilds was higher in the plantation. The results of the study show that the conversion of forest to either oil palm plantation or paddy fields produced a decline in bird diversity and changes in the distribution of bird feeding guilds. PMID:24575217

Microbial characteristics of purple paddy soil in response to Pb pollution.

PubMed

Jiang, Qiu-Ju; Zhang, Yue-Qiang; Zhang, La-Mei; Zhou, Xin-Bin; Shi, Xiao-Jun

2014-05-01

The study focused on the change of microbial characteristics affected by Plumbum pollution with purple paddy soil in an incubation experiment. The results showed that low concentration of Plumbum had little effect on most of microbial amounts, biological activity and enzymatic activity. However, denitrifying activity was inhibited severely, and inhibition rate was up to 98%. Medium and high concentration of Plumbum significantly reduced the amounts and activity of all microorganisms and enzymatic activity, which increased with incubation time. Negative correlations were found between Plumbum concentrations and microbial amounts, biological activity and enzymatic activities except fungi and actinomyces. Thus they can be used to indicate the Plumbum pollution levels to some extent. LD(50) of denitrifying bacteria (DB) and ED50 of denitrifying activity were 852mg/kg and 33.5mg/kg. Across all test soil microbes, denitrifying bacteria was most sensitive to Plumbum pollution in purple paddy soil. Value of early warning showed that anaerobic cellulose-decomposing bacteria (ACDB) and actinomyces were also sensitive to Plumbum pollution. We concluded that denitrifying activity, actinomyces, ACDB or DB can be chosen as predictor of Plumbum contamination in purple paddy soil.

[Effects of cropping patterns on photosynthesis characteristics of summer maize and its utilization of solar and heat resources].

PubMed

Zhu, Yuan-Gang; Dong, Shu-Ting; Zhang, Ji-Wang; Liu, Peng; Yang, Jin-Sheng; Jia, Chun-Lan; Liu, Jing-Guo; Li, Deng-Hai

2010-06-01

In order to investigate the effects of interplanting and direct seeding on the photosynthesis characteristics of summer maize and its utilization of solar and heat resources, two summer maize cultivars (Zhengdan 958 and Denghai 661) were planted in the farmlands of Denghai Seed Co. Ltd in Laizhou City of Shandong Province, with 67500 plants x hm(-2) and three sowing dates. The above-ground biomass, plant growth rate, leaf area index, and net photosynthetic rate per ear leaf were measured to reveal the photosynthesis characteristics of test cultivars. In the meantime, the characters of grain-filling were simulated by Richards' model, and the solar resource utilization efficiency of the cultivars was calculated, in combining with meteorological data. Comparing with interplanting, direct seeding increased the grain yield by 1.17%-3.33%, but decreased the thousand-grain weight significantly. Growth stages were extended under earlier sowing. The leaf area index and net photosynthetic rate from flowering to 30 d after anthesis were significantly higher under direct seeding than under interplanting, but after then, they decreased faster. Direct seeding induced a higher accumulation of dry matter and a faster plant growth rate before and after flowering. Under direct seeding, the maximum grain-filling rate reached earlier, the starting potential was higher, but the grain-filling period, active grain-filling period, and W(max) were lower, compared with those under interplanting. Also under direct seeding, the total accumulative temperature and solar radiation during growth period decreased by 150-350 degrees C x d and 200-400 MJ x m(-2), respectively, but the solar resource utilization efficiency of grain increased by 10.5%-24.7%. All the results suggested that direct seeding was superior to interplanting for the summer maize production under field condition. In order to enhance solar and heat utilization efficiency and excavate yield potential, it would be essential to improve the leaf photosynthesis efficiency and postpone leaf aging.

Forest rodents provide directed dispersal of Jeffrey pine seeds

USGS Publications Warehouse

Briggs, J.S.; Wall, S.B.V.; Jenkins, S.H.

2009-01-01

Some species of animals provide directed dispersal of plant seeds by transporting them nonrandomly to microsites where their chances of producing healthy seedlings are enhanced. We investigated whether this mutualistic interaction occurs between granivorous rodents and Jeffrey pine (Pinus jeffreyi) in the eastern Sierra Nevada by comparing the effectiveness of random abiotic seed dispersal with the dispersal performed by four species of rodents: deer mice (Peromyscus maniculatus), yellow-pine and long-eared chipmunks (Tamias amoenus and T. quadrimaculatus), and golden-mantled ground squirrels (Spermophilus lateralis). We conducted two caching studies using radio-labeled seeds, the first with individual animals in field enclosures and the second with a community of rodents in open forest. We used artificial caches to compare the fates of seeds placed at the range of microsites and depths used by animals with the fates of seeds dispersed abiotically. Finally, we examined the distribution and survival of naturally establishing seedlings over an eight-year period.Several lines of evidence suggested that this community of rodents provided directed dispersal. Animals preferred to cache seeds in microsites that were favorable for emergence or survival of seedlings and avoided caching in microsites in which seedlings fared worst. Seeds buried at depths typical of animal caches (5–25 mm) produced at least five times more seedlings than did seeds on the forest floor. The four species of rodents differed in the quality of dispersal they provided. Small, shallow caches made by deer mice most resembled seeds dispersed by abiotic processes, whereas many of the large caches made by ground squirrels were buried too deeply for successful emergence of seedlings. Chipmunks made the greatest number of caches within the range of depths and microsites favorable for establishment of pine seedlings. Directed dispersal is an important element of the population dynamics of Jeffrey pine, a dominant tree species in the eastern Sierra Nevada. Quantifying the occurrence and dynamics of directed dispersal in this and other cases will contribute to better understanding of mutualistic coevolution of plants and animals and to more effective management of ecosystems in which directed dispersal is a keystone process.

Promising native forbs for seeding on mine spoils

Treesearch

Ardell J. Bjugstad; Warren C. Whitman

1989-01-01

Twenty nine species of perennial forbs and 2 biennial forbs were directly seeded into coal mine spoil materials at Dickinson, North Dakota to determine which species would be most successful for direct seeding into coal mine spoil. Those which showed exceptionally good emergence and vigorous growth of seedlings in a two year study were: white prairie clover (...

On-site production of crude glucoamylase for kitchen waste hydrolysis.

PubMed

Wang, Xiao Qiang; Wang, Qun Hui; Liu, Ying Ying; Ma, Hong Zhi

2010-06-01

Kitchen waste from dining rooms accounts for a considerable proportion of municipal solid garbage, and economical recycle ways are needed to be developed. This study investigated glucoamylase production from kitchen waste and the feasibility of kitchen waste hydrolysis by the crude enzymes produced. The key problems of high water content and poor porosity in kitchen waste for glucoamylase production under solid-state fermentation could be solved readily by the addition of corn stover or paddy husk. As a support medium, corn stover was better than paddy husk. Smashed kitchen waste (sKW) mixed with corn stover in the ratio of 3.75 : 1 (dry basis) produced 1838 U g(-1) of glucoamylase by Aspergillus niger UV-60 within 96 h. The enzyme productivity from kitchen waste was over two-fold higher than that from wheat bran with additional nutrients. Without any recovery treatment, the produced glucoamylase could be used directly to hydrolyse sKW slurry. The optimum enzyme dose 8% (crude enzyme/kichen waste, w/w) was not too big, and was sufficient to hydrolyse 10% (dry basis) sKW slurry to produce a maximum amount of reducing sugar of 55.4 g L(-1).

Relationships between soil heavy metal pollution and enzyme activities in mining areas of northern Hunan province, Central South China

NASA Astrophysics Data System (ADS)

Hu, Xue-Feng; Jiang, Ying; Shu, Ying

2014-05-01

Hunan province, Central South China, is a well-known nonferrous metal base in China. Mine exploiting and processing there, however, often lead to heavy metal pollution of farmland. To study the effects of mining activities on the soil environmental quality, four representative paddy fields, the HSG, SNJ, NT and THJ, in Y county, northern Hunan province, were investigated. It was found that the streams running through the HSG, SNJ and NT are severely contaminated due to the long-term discharge of untreated mineral wastewater from local indigenous mining factories. The stream at the HSG, for example, is brownish red in color, with high concentrations of Cu, Zn, Cd, Fe and Mn. The concentrations of Cu, Zn and Cd in all the stream water of the HSG, SNJ and NT exceed the maximum allowable levels of the Agricultural Irrigation Water Criteria of China. Correspondingly, the HSG, SNJ and NT are heavily polluted by Cu, Zn and Cd due to the long-term irrigation with the contaminated stream water. In comparison, both stream water and paddy fields of the THJ, far away from mining areas, are not contaminated by any heavy metals and hence regarded as a control in this study. The rice grain produced at the HSG, SNJ and NT has a high risk of Cd contamination. The rate of rice grain produced in the four paddy fields in Y county with Cd exceeding the safe level (Cd, 0.2 μg g-1) specified by the National Standards for Rice Quality and Safety of China reaches 90%. Cd content in the rice grain is positively significantly correlated with that in the paddy fields, especially with the content of diethylenetriaminepentaacetic acid (DTPA) - extracted Cd, suggesting that the heavy metal pollution of paddy fields has already posed a high risk to rice safety and human health. Soil enzyme activities and microbial biomass are significantly inhibited by the heavy metal pollution of the paddy fields. Microbial biomass C and N (MBC and MBN) at a severely contaminated site of the HSG are only 31.6% and 64.4% of the controls; the activities of dehydrogenase, urease, catalase, acid and neutral phosphatase and sucrase are only 25.2%, 49.3%, 52.4%, 94.7%, 53.2% and 87.8% of the controls. These microbial parameters are mostly negatively significantly correlated with the contents of Cu, Zn, Cd and Ni in the paddy fields, suggesting the toxic effects of the heavy metals on microbial processes. Both the Principal Component Analysis (PCA) and Cluster Analysis (CA) indicated that DH activity and MBC are the most sensitive to the heavy metal pollution and could be used as eco-indicators of the environmental quality of the paddy fields in the study areas. Acknowledgements: This work was supported by the National Natural Science Foundation of China (No. 41130526).

Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide.

PubMed

Chandra, B P; Sinha, Vinayak

2016-03-01

In the north west Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October-November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r≥0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62±0.18ppb), benzene (2.51±0.28ppb), toluene (3.72±0.41ppb), C8-aromatics (2.88±0.30ppb), C9-aromatics (1.55±0.19ppb) and CO (552±113ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97±0.17ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of benzene and ensure compliance with the NAAQS. Calculations of excessive lifetime cancer risk due to benzene amount to 25 and 10 per million inhabitants for children and adults, respectively, exceeding the USEPA threshold of 1 per million inhabitants. Annual exposure to isocyanic acid was close to 1ppb, the concentration considered to be sufficient to enhance risks for cardiovascular diseases and cataracts. This study makes a case for urgent mitigation of post-harvest paddy residue fires as the unknown synergistic effect of multi-pollutant exposure due to emissions from this anthropogenic source may be posing grave health risks to the population of the N.W. IGP. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tumour seeding after percutaneous cryoablation for hepatocellular carcinoma

PubMed Central

Wang, Chun-Ping; Wang, Hong; Qu, Jian-Hui; Lu, Yin-Ying; Bai, Wen-Lin; Dong, Zheng; Gao, Xu-Dong; Rong, Guang-Hua; Zeng, Zhen; Yang, Yong-Ping

2012-01-01

AIM: To assess the rate and risk factors for tumour seeding in a large cohort of patients. METHODS: Over an 8-year period, 1436 hepatocellular carcinoma (HCC) patients with 2423 tumour nodules underwent 3015 image-guided percutaneous cryoablation sessions [1215 guided by ultrasonography and 221 by spiral computed tomography (CT)]. Follow-up CT or magnetic resonance imaging was performed every 3 mo. The detailed clinical data were recorded to analyse the risk factors for seeding. RESULTS: The median follow-up time was 18 (range 1-90) mo. Seeding was detected in 11 patients (0.76%) at 1-24 (median 6.0) mo after cryoablation. Seeding occurred along the needle tract in 10 patients and at a distant location in 1 patient. Seeded tumours usually showed similar imaging and histopathological features to the primary HCCs. Univariate analyses identified subcapsular tumour location and direct subcapsular needle insertion as risk factors for seeding. Multivariate analysis showed that only direct subcapsular needle insertion was an independent risk factor for seeding (P = 0.017; odds ratio 2.57; 95%CI: 1.47-3.65). Seeding after cryoablation occurred earlier in patients with poorly differentiated HCC than those with well or moderately differentiated HCC [1.33 ± 0.577 mo vs 11.12 ± 6.896 mo; P = 0.042; 95%CI: (-19.115)-(-0.468)]. CONCLUSION: The risk of seeding after cryoablation for HCC is small. Direct puncture of subcapsular tumours should be avoided to minimise seeding. PMID:23236233

Genome Sequence of the Verrucomicrobium Opitutus terrae PB90-1, an Abundant Inhabitant of Rice Paddy Soil Ecosystems▿

PubMed Central

van Passel, Mark W. J.; Kant, Ravi; Palva, Airi; Copeland, Alex; Lucas, Susan; Lapidus, Alla; Glavina del Rio, Tijana; Pitluck, Sam; Goltsman, Eugene; Clum, Alicia; Sun, Hui; Schmutz, Jeremy; Larimer, Frank W.; Land, Miriam L.; Hauser, Loren; Kyrpides, Nikolaos; Mikhailova, Natalia; Richardson, P. Paul; Janssen, Peter H.; de Vos, Willem M.; Smidt, Hauke

2011-01-01

Bacteria of the deeply branching phylum Verrucomicrobia are rarely cultured yet commonly detected in metagenomic libraries from aquatic, terrestrial, and intestinal environments. We have sequenced the genome of Opitutus terrae PB90-1, a fermentative anaerobe within this phylum, isolated from rice paddy soil and capable of propionate production from plant-derived polysaccharides. PMID:21398538

Inorganic Nitrogen Leaching from Organic and Conventional Rice Production on a Newly Claimed Calciustoll in Central Asia

PubMed Central

Meng, Fanqiao; Olesen, Jørgen E.; Sun, Xiangping; Wu, Wenliang

2014-01-01

Characterizing the dynamics of nitrogen (N) leaching from organic and conventional paddy fields is necessary to optimize fertilization and to evaluate the impact of these contrasting farming systems on water bodies. We assessed N leaching in organic versus conventional rice production systems of the Ili River Valley, a representative aquatic ecosystem of Central Asia. The N leaching and overall performance of these systems were measured during 2009, using a randomized block experiment with five treatments. PVC pipes were installed at soil depths of 50 and 180 cm to collect percolation water from flooded organic and conventional paddies, and inorganic N (NH4-N+NO3-N) was analyzed. Two high-concentration peaks of NH4-N were observed in all treatments: one during early tillering and a second during flowering. A third peak at the mid-tillering stage was observed only under conventional fertilization. NO3-N concentrations were highest at transplant and then declined until harvest. At the 50 cm soil depth, NO3-N concentration was 21–42% higher than NH4-N in percolation water from organic paddies, while NH4-N and NO3-N concentrations were similar for the conventional and control treatments. At the depth of 180 cm, NH4-N and NO3-N were the predominant inorganic N for organic and conventional paddies, respectively. Inorganic N concentrations decreased with soil depth, but this attenuation was more marked in organic than in conventional paddies. Conventional paddies leached a higher percentage of applied N (0.78%) than did organic treatments (0.32–0.60%), but the two farming systems leached a similar amount of inorganic N per unit yield (0.21–0.34 kg N Mg−1 rice grains). Conventional production showed higher N utilization efficiency compared to fertilized organic treatments. These results suggest that organic rice production in the Ili River Valley is unlikely to reduce inorganic N leaching, if high crop yields similar to conventional rice production are to be maintained. PMID:24858826

Effects of water-saving irrigation on the residues and risk of polycyclic aromatic hydrocarbon in paddy field.

PubMed

Zhao, Zhenhua; Xia, Liling; Jiang, Xin; Gao, Yanzheng

2018-03-15

The effects of different water-saving modes on PAHs residue and risk, field environment conditions and enzyme activities in paddy field were investigated in a field experiment plot in Laoyaba, Nanjing, China. Results showed that (1) water-saving treatment affected greatly the ΣPAHs in water and soil. The order of ΣPAHs residue in surface water and groundwater in farmland is as follows: dry fieldsroot>stem>rice grain. (4) Water-saving irrigation evidently decreased soil ecological risk (up to 55%-73%) and rice carcinogenic risk (up to 30%-45%) caused by PAHs compared with flooding irrigation. Water-saving irrigation could also reduce the Total Toxic Equivalency Concentration of PAHs in rice grain up to 50% relative to flooding irrigation. (5) The significant negative correlations were observed between the residual PAHs and the activities of laccase and dioxygenase (p<0.019), and the physical and chemical indexes (temperature, redox potential and dissolved oxygen of field, p<0.041). The changes of field environment conditions and enzyme activities induced by moisture control may be the main key factors affecting PAHs residue in water, soil and rice. Copyright © 2017. Published by Elsevier B.V.

Knowledge and self-reported practices regarding leptospirosis among adolescent school children in a highly endemic rural area in Sri Lanka.

PubMed

Samarakoon, Yasara M; Gunawardena, Nalika

2013-01-01

Leptospirosis is a zoonotic disease, which has become a major public health threat in Sri Lanka. A majority of patients are farmers in rural endemic areas. The purpose of the present study is to describe the level of knowledge and frequencies of risky practices related to leptospirosis among a sample of rural school adolescents in Galgamuwa, Kurunegala district, a highly endemic area in Sri Lanka. A descriptive cross-sectional study was conducted among 460 adolescents studying in grades 9 and 10 of government schools. Study participants were selected using a multistage cluster sampling technique. A structured, pretested, self-administered questionnaire was used to collect data on sociodemographic characteristics, knowledge on leptospirosis, and frequency of associated risky practices related to leptospirosis. The response rate was 100%. Fifty-two percent of respondents had a 'good' level of knowledge of leptospirosis. In the assessment of practices, 62% were involved in rice paddy cultivation either 'frequently' or 'rarely'. Seventy percent of the fathers and 50% of the mothers of the students were involved in paddy cultivation. Thirteen percent reported that they swam, bathed, or washed in ponds of stagnant water. Of the students involved in paddy cultivation, only 18% said they usually used gloves and boots 'frequently'. Among the 9% of students who handled cattle or buffalo, 61% reported washing their hands and feet after handling the animals. Good level of knowledge was significantly associated with involvement in paddy cultivation among the adolescents (p=0.45), fathers (p<0.001), and mothers (p=0.012). The level of knowledge was not significantly associated with practicing preventive measures for leptospirosis. Although the respondent's overall level of knowledge regarding leptospirosis was satisfactory, the study identified several important gaps in specific areas. Those who were involved or had parents involved in paddy cultivation had better knowledge. However, this knowledge was not translated into practice of personal preventive measures. Use of protective attire in paddy farming needs to be facilitated by health authorities.

Downward migration of radiocesium in an abandoned paddy soil after the Fukushima Dai-ichi Nuclear Power Plant accident.

PubMed

Takahashi, Junko; Wakabayashi, Shokichi; Tamura, Kenji; Onda, Yuichi

2018-02-01

After the Fukushima Dai-ichi Nuclear Power Plant accident on March 2011, continuous monitoring of the detailed vertical distribution of radiocesium in soil is required to evaluate the fate of radiocesium and establish strategies for remediation and management of the contaminated land. It is especially important to investigate paddy soil because little knowledge has been accumulated for paddy soil and wetland rice is a major staple in Japan. Therefore, we monitored the vertical distribution of 137 Cs in abandoned paddy soil in a planned evacuation zone from June 2011 to March 2016. The decontamination works (i.e., 5 cm of surface soil removal and re-covering with uncontaminated soil) were conducted by the government in 2015. As a result of monitoring, the 137 Cs gradually migrated downward with time and the 137 Cs concentration in the 0-10 cm soil was almost homogenous in October 2014, although it was non-cultivated. The liner relationship was obtained between the median depth, which is the thickness of a soil layer containing half of the total 137 Cs inventory, and the time after the accident, indicating the migration rate was constant (1.3 cm y -1 ) before the decontamination works. After the decontamination works, the 137 Cs concentration in the uppermost surface layer was reduced by 90%, however the total 137 Cs inventory was reduced by only 50-70%. It was shown that the efficiency of 137 Cs removal by the decontamination works decrease linearly over time in fields like the studied paddy, in which the homogenization of 137 Cs concentration occurred. Conversely, the downward migration of 137 Cs to subsurface layers deeper than 10 cm (i.e., plowpan layer) with low permeability rarely occurred. It is expected that these unique trends in distribution and migration of 137 Cs would be found in abandoned paddy soils with properties similar to the studied soil, sandy loam but poorly drained because of the low permeable plowpan layer, although further validation is necessary. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Effects of controlled release nitrogen fertilizer on surface water N dynamics and its runoff loss in double cropping paddy fields in Dongtinghu Lake area].

PubMed

Ji, Xiong-Hui; Zheng, Sheng-Xian; Lu, Yan-Hong; Liao, Yu-Lin

2007-07-01

By using leakage pond to simulate the double cropping paddy fields in Dongtinghu Lake area, this paper studied the effects of urea (CF) and controlled release nitrogen fertilizer (CRNF) on the dynamics of surface water pH, electrical conductivity (EC), total nitrogen (TN), ammonia nitrogen (NH4(+)-N) and nitrate nitrogen (NO3(-)-N) and the runoff loss of TN in alluvial sandy loamy paddy soil and purple calcareous clayed paddy soil, the two main paddy soils in this area. The results showed that after applying urea, the surface water TN and NH4(+)-N concentrations reached the peak at the 1st and 3rd day, respectively, and decreased rapidly then. Surface water NO3(-)-N concentration was very low, though it showed a little raise at the 3rd to 7th day after applying urea in purple calcareous clayed paddy soil. In early rice field, surface water pH rose gradually within 15 days after applying urea, while in late rice field, it did within 3 days. EC kept consistent with the dynamics of NH4(+)-N. CRNF, especially 70% N CRNF, gave rise to distinctly lower surface water pH, EC, and TN and NH4(+)-N concentrations within 15 days after application, but NO3- concentration rose slightly at late growth stages, compared with urea application. The monitoring of TN runoff loss indicated that during double cropping rice growth season, the loss amount of TN under urea application was 7.70 kg x hm(-2), accounting for 2.57% of applied urea-N. The two runoff events occurred within 20 days after urea application contributed significantly to the TN runoff loss. CRNF application resulted in a significantly lower TN concentration in runoff water from the 1st runoff event occurred within 10 days of its application, and thereafter, the total TN runoff loss for CRNF and 70% N CRNF application was decreased by 24.5% and 27.2%, respectively, compared with urea application.

Effects of methanol-to-oil ratio, catalyst amount and reaction time on the FAME yield by in situ transesterification of rubber seeds (Hevea brasiliensis)

NASA Astrophysics Data System (ADS)

Abdulkadir, Bashir Abubakar; Uemura, Yoshimitsu; Ramli, Anita; Osman, Noridah B.; Kusakabe, Katsuki; Kai, Takami

2014-10-01

In this research, biodiesel is produced by in situ transesterification (direct transesterification) method from the rubber seeds using KOH as a catalyst. The influence of methanol to seeds mass ratio, duration of reaction, and catalyst loading was investigated. The result shows that, the best ratio of seeds to methanol is 1:6 (10 g seeds with 60 g methanol), 120 minutes reaction time and catalyst loading of 3.0 g. The maximum FAME yield obtain was 70 %. This findings support FAME production from the seeds of rubber tree using direct transesterifcation method from the seeds of rubber tree as an alternative to diesel fuel. Also, significant properties of biodiesel such as cloud point, density, pour point, specific gravity, and viscosity were investigated.

Site Index Curves for Direct-Seeded Loblolly and Longleaf Pines in Louisiana

Treesearch

Quang V. Cao; V. Clark Baldwin; Richard E. Lohrey

1995-01-01

Site index equations were developed for direct-seeded loblollypine (Pinus taeda L.) and longleaf pine (Pinus palustris Mill.) based on data from 148 and 75 permanent plots, respectively. These plots varied from 0.053 to 0.119 ac in size, and were established in broadcast, row, and spot seeded stands throughout Louisiana. The Bailey and Clutter (1974) model was...

Direct Seeding of Southern Oaks - A Progress Report

Treesearch

Robert L. Johnson; Roger M. Krinard

1987-01-01

Since 1981 over 4,000 acres of publicly and privately owned land, mostly in flood plains, have been direct seeded with acorns. Most seedings have been in abandoned farm land, the rest in forest openings created by commercial tree harvest. Cost data associated with a few of the production trials are presented in this paper. Also included are discussions of production...

Abundance, Composition and Activity of Ammonia Oxidizer and Denitrifier Communities in Metal Polluted Rice Paddies from South China

PubMed Central

Liu, Yuan; Liu, Yongzhuo; Ding, Yuanjun; Zheng, Jinwei; Zhou, Tong; Pan, Genxing; Crowley, David; Li, Lianqing; Zheng, Jufeng; Zhang, Xuhui; Yu, Xinyan; Wang, Jiafang

2014-01-01

While microbial nitrogen transformations in soils had been known to be affected by heavy metal pollution, changes in abundance and community structure of the mediating microbial populations had been not yet well characterized in polluted rice soils. Here, by using the prevailing molecular fingerprinting and enzyme activity assays and comparisons to adjacent non-polluted soils, we examined changes in the abundance and activity of ammonia oxidizing and denitrifying communities of rice paddies in two sites with different metal accumulation situation under long-term pollution from metal mining and smelter activities. Potential nitrifying activity was significantly reduced in polluted paddies in both sites while potential denitrifying activity reduced only in the soils with high Cu accumulation up to 1300 mg kg−1. Copy numbers of amoA (AOA and AOB genes) were lower in both polluted paddies, following the trend with the enzyme assays, whereas that of nirK was not significantly affected. Analysis of the DGGE profiles revealed a shift in the community structure of AOA, and to a lesser extent, differences in the community structure of AOB and denitrifier between soils from the two sites with different pollution intensity and metal composition. All of the retrieved AOB sequences belonged to the genus Nitrosospira, among which species Cluster 4 appeared more sensitive to metal pollution. In contrast, nirK genes were widely distributed among different bacterial genera that were represented differentially between the polluted and unpolluted paddies. This could suggest either a possible non-specific target of the primers conventionally used in soil study or complex interactions between soil properties and metal contents on the observed community and activity changes, and thus on the N transformation in the polluted rice soils. PMID:25058658

Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

PubMed

Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

2016-02-01

Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising. Copyright © 2015 Elsevier Ltd. All rights reserved.

How Does Recycling of Livestock Manure in Agroecosystems Affect Crop Productivity, Reactive Nitrogen Losses, and Soil Carbon Balance?

PubMed

Xia, Longlong; Lam, Shu Kee; Yan, Xiaoyuan; Chen, Deli

2017-07-05

Recycling of livestock manure in agroecosystems to partially substitute synthetic fertilizer nitrogen (N) input is recommended to alleviate the environmental degradation associated with synthetic N fertilization, which may also affect food security and soil greenhouse gas (GHG) emissions. However, how substituting livestock manure for synthetic N fertilizer affects crop productivity (crop yield; crop N uptake; N use efficiency), reactive N (Nr) losses (ammonia (NH 3 ) emission, N leaching and runoff), GHG (methane, CH 4 ; and nitrous oxide, N 2 O; carbon dioxide) emissions and soil organic carbon (SOC) sequestration in agroecosystems is not well understood. We conducted a global meta-analysis of 141 studies and found that substituting livestock manure for synthetic N fertilizer (with equivalent N rate) significantly increased crop yield by 4.4% and significantly decreased Nr losses via NH 3 emission by 26.8%, N leaching by 28.9% and N runoff by 26.2%. Moreover, annual SOC sequestration was significantly increased by 699.6 and 401.4 kg C ha -1 yr -1 in upland and paddy fields, respectively; CH 4 emission from paddy field was significantly increased by 41.2%, but no significant change of that was observed from upland field; N 2 O emission was not significantly affected by manure substitution in upland or paddy fields. In terms of net soil carbon balance, substituting manure for fertilizer increased carbon sink in upland field, but increased carbon source in paddy field. These results suggest that recycling of livestock manure in agroecosystems improves crop productivity, reduces Nr pollution and increases SOC storage. To attenuate the enhanced carbon source in paddy field, appropriate livestock manure management practices should be adopted.

Seasonal Changes in the Percentage of Rice Stripe Virus Viruliferous Laodelphax striatellus (Hemiptera: Delphacidae) in Paddy Fields in Japan.

PubMed

Shiba, Takuya; Hirae, Masahiro; Hayano-Saito, Yuriko; Uematsu, Hiroshi; Sasaya, Takahide; Higuchi, Hiroya; Ohto, Yasuo; Okuda, Mitsuru

2016-04-20

Rice stripe disease, which is caused by Rice stripe virus (RSV), is one of the most serious viral diseases of rice. RSV is transmitted in a persistent manner byLaodelphax striatellus(Fallén). The incidence of the disease can be estimated from the density of viruliferous vectors. Understanding seasonal changes of the percentage of viruliferousL. striatelluscan facilitate forecasting and controlling the disease. In paddies, the percentage of viruliferous insects fluctuated in phase with the rate of detection of RSV-infected rice; it gradually increased from July to August, plateaued or temporarily declined in September, and increased sharply on ratoons in October. These findings indicate that horizontal transmission of RSV from diseased plants to vector insects occurred frequently, and the insects acquired RSV from the ratoons. However, the percentages of viruliferous insects overwintering in poaceous weeds, the main hosts forL. striatellusin winter, were lower than those in ratoons. FewL. striatellusthat acquired RSV from ratoons seemed to move to overwintering sites and transmit the virus to the next generation. However, there was a tendency for the percentages of viruliferous overwintering insects to be higher on paddy ridges than in river levees. Insects could probably move from ratoons to poaceous weeds when the weeds were near a paddy. Although increasing percentage of viruliferous insects on ratoons seem to have relatively little impact on RSV dynamics in the next crop season, appropriate weed management around paddies is still needed to reduce the incidence of rice stripe disease. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Continuous in-situ methane measurements at paddy fields in a rural area of India with poor electric infrastructure, using a low-cost instrument based on open-path near-IR laser absorption spectroscopy

NASA Astrophysics Data System (ADS)

Hidemori, T.; Matsumi, Y.; Nakayama, T.; Kawasaki, M.; Sasago, H.; Takahashi, K.; Imasu, R.; Takeuchi, W.; Adachi, M.; Machida, T.; Terao, Y.; Nomura, S.; Dhaka, S. K.; Singh, J.

2015-12-01

In southeast and south Asia, the previous satellite observations suggest that the methane emission from rice paddies is significant and important source of methane during rainy season. Since it is difficult to measure methane stably and continuously at rural areas such as the paddy fields in terms of infrastructures and maintenances, there are large uncertainties in quantitative estimation of methane emission in these areas and there are needs for more certification between satellite and ground based measurements. To measure methane concentrations continuously at difficult situations such as the center of paddy fields　and wetlands, we developed the continuous in-situ measurement system, not to look for your lost keys under the streetlight. The methane gas sensor is used an open-path laser based measurement instrument (LaserMethane, ANRITSU CORPORATION), which can quickly and selectively detect average methane concentrations on the optical path of the laser beam. The developed system has the power supply and telecommunication system to run the laser gas sensor in rural areas with poor electricity infrastructure.The methane measurement system was installed at paddy fields of Sonepat, Haryana on the north of Delhi in India and has been operated from the end of 2014. The air sampling along with our measurement has been carried out once a week during daytime to calibrate the laser instrument. We found that the seasonal variation of methane concentrations was different from the satellite observations and there were significant diurnal variations, which it was difficult to detect from occasional air samplings. We will present details of the measurement system and recent results of continuous methane measurements in India.

Effect of Elevated CO2 Concentration, Elevated Temperature and No Nitrogen Fertilization on Methanogenic Archaeal and Methane-Oxidizing Bacterial Community Structures in Paddy Soil

PubMed Central

Liu, Dongyan; Tago, Kanako; Hayatsu, Masahito; Tokida, Takeshi; Sakai, Hidemitsu; Nakamura, Hirofumi; Usui, Yasuhiro; Hasegawa, Toshihiro; Asakawa, Susumu

2016-01-01

Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions. PMID:27600710

Quantifying differences in water and carbon cycling between paddy and rainfed rice (Oryza sativa L.) by flux partitioning.

PubMed

Nay-Htoon, Bhone; Xue, Wei; Lindner, Steve; Cuntz, Matthias; Ko, Jonghan; Tenhunen, John; Werner, Christiane; Dubbert, Maren

2018-01-01

Agricultural crops play an important role in the global carbon and water cycle. Global climate change scenarios predict enhanced water scarcity and altered precipitation pattern in many parts of the world. Hence, a mechanistic understanding of water fluxes, productivity and water use efficiency of cultivated crops is of major importance, i.e. to adapt management practices. We compared water and carbon fluxes of paddy and rainfed rice by canopy scale gas exchange measurements, crop growth, daily evapotranspiration, transpiration and carbon flux modeling. Throughout a monsoon rice growing season, soil evaporation in paddy rice contributed strongly to evapotranspiration (96.6% to 43.3% from initial growth to fully developed canopy and amounted to 57.9% of total water losses over the growing seasons. Evaporation of rainfed rice was significantly lower (by 65% on average) particularly before canopy closure. Water use efficiency (WUE) was significantly higher in rainfed rice both from an agronomic (WUEagro, i.e. grain yield per evapotranspiration) and ecosystem (WUEeco, i.e. gross primary production per evapotranspiration) perspective. However, our results also show that higher WUE in rainfed rice comes at the expense of higher respiration losses compared to paddy rice (26% higher on average). Hence, suggestions on water management depend on the regional water availability (i.e. Mediterranean vs. Monsoon climate) and the balance between higher respiratory losses versus a potential reduction in CH4 and other greenhouse gas emissions. Our results suggest that a shift from rainfed/unsaturated soil to waterlogged paddy conditions after closure of the rice canopy might be a good compromise towards a sustainable use of water while preserving grain yield, particularly for water-limited production areas.

Mechanism of matrix-bound phosphine production in response to atmospheric elevated CO2 in paddy soils.

PubMed

An, Shaorong; Niu, Xiaojun; Chen, Weiyi; Sheng, Hong; Lai, Senchao; Yang, Zhiquan; Gu, Xiaohong; Zhou, Shaoqi

2018-04-12

To explore the effect of elevated CO 2 concentrations ([CO 2 ]) on phosphine formation in paddy fields, the matrix-bound phosphine (MBP) content, different phosphorus fractions and various carbon forms in soil samples from rice cultivation under varying CO 2 concentrations of 400 ppm, 550 ppm and 700 ppm by indoor simulation experiment were determined. This study showed that MBP concentration did not increase significantly with elevated [CO 2 ] over four-week cultivation periods of rice seedlings, regardless of soil layers. MBP had a significant positive correlation with total phosphorus (TP) and inorganic phosphorus (IP), and multiple stepwise linear regression analysis further indicated that MBP preservation in neutral paddy soils with depths of 0-20 cm may have been due to conversion from FeP and CaP. Based on redundancy analysis and forward selection analysis, speculated that the formation of MBP in the neutral paddy soils as the response to atmospheric elevated [CO 2 ] was due to two processes: (i) FeP transformation affected by the changes of soil respiration (SCO 2 ) and TOC was the main precursor for the production of MBP; and (ii) CaP transformation resulting from variation in HCO 3 - was the secondary MBP source. The complex combination of these two processes is simultaneously controlled by SCO 2 . In a word, the soil environment in the condition of elevated [CO 2 ] was in favor of MBP storage in neutral paddy soils. The results of our study imply that atmospheric CO 2 participates in and has a certain impact on the global biogeochemical cycle of phosphorus. Copyright © 2018 Elsevier Ltd. All rights reserved.

Heavy metal speciation and risk assessment in dry land and paddy soils near mining areas at Southern China.

PubMed

Liu, Guannan; Wang, Juan; Zhang, Erxi; Hou, Jing; Liu, Xinhui

2016-05-01

Heavy metal contamination of soils has been a long-standing environmental problem in many parts of the world, and poses enormous threats to ecosystem and human health. Speciation of heavy metals in soils is crucial to assessing environmental risks from contaminated soils. In this study, total concentrations and speciation of As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn were measured for agricultural soils near mines along the Diaojiang River in Guangxi Zhuang Autonomy Region, China. The sources of heavy metals in soils also were identified to assess their effect on speciation distribution of soil heavy metals. Furthermore, the speciation distribution of Cd and Zn, main soil heavy metal pollutants, in dry land and paddy soils were compared. Results showed that there were two severely polluted regions near mine area reaching alarming pollution level. As, Cd, Pb, and Zn were more affected by mining activities, showing very strong pollution level in soils. The mean percentage of exchangeable and carbonate fraction was highest and up to 46.8 % for Cd, indicating a high environmental risk. Greater bioavailable fractions of As, Cd, Cu, Mn, Pb, and Zn were found in soils heavily polluted by mining activities, whereas Cr and Ni as geogenic elements in the stable residual fraction. In addition, in the dry land soils, reducible fraction proportion of Cd was higher than that in the paddy soils, whereas exchangeable and carbonate fraction of Cd was lower than that in the paddy soils. Oxidizable fraction of Zn was higher in the paddy soils than that in the dry land soils. The results indicate that the sources of soil heavy metals and land types affect heavy metal speciation in the soil and are significant for environmental risk assessment of soil heavy metal pollutions.

Influence of transgenic rice expressing a fused Cry1Ab/1Ac protein on frogs in paddy fields.

PubMed

Wang, Jia-Mei; Chen, Xiu-Ping; Liang, Yu-Yong; Zhu, Hao-Jun; Ding, Jia-Tong; Peng, Yu-Fa

2014-11-01

As genetic engineering in plants is increasingly used to control agricultural pests, it is important to determine whether such transgenic plants adversely affect non-target organisms within and around cultivated fields. The cry1Ab/1Ac fusion gene from Bacillus thuringiensis (Bt) has insecticidal activity and has been introduced into rice line Minghui 63 (MH63). We evaluated the effect of transgenic cry1Ab/1Ac rice (Huahui 1, HH1) on paddy frogs by comparing HH1 and MH63 rice paddies with and without pesticide treatment. The density of tadpoles in rice fields was surveyed at regular intervals, and Cry1Ab/1Ac protein levels were determined in tissues of tadpoles and froglets collected from the paddy fields. In addition, Rana nigromaculata froglets were raised in purse nets placed within these experimental plots. The survival, body weight, feeding habits, and histological characteristics of the digestive tract of these froglets were analyzed. We found that the tadpole density was significantly decreased immediately after pesticide application, and the weight of R. nigromaculata froglets of pesticide groups was significantly reduced compared with no pesticide treatment, but we found no differences between Bt and non-Bt rice groups. Moreover, no Cry1Ab/1Ac protein was detected in tissue samples collected from 192 tadpoles and froglets representing all four experimental groups. In addition, R. nigromaculata froglets raised in purse seines fed primarily on stem borer and non-target insects, and showed no obvious abnormality in the microstructure of their digestive tracts. Based on these results, we conclude that cultivation of transgenic cry1Ab/1Ac rice does not adversely affect paddy frogs.

Efficacy of pine leaves as an alternative bedding material for broiler chicks during summer season

PubMed Central

Sharma, Gourav; Khan, Asma; Singh, Surender; Anand, Ashok Kumar

2015-01-01

Aim: The aim was to assess the efficacy of pine leaves as an alternative bedding material on the performance of broiler chicks. Materials and Methods: The present study was conducted in summer. Total 120, day old Vencobb straight run chicks were procured, and after 5 days of brooding, chicks were randomly distributed into four treatment groups viz. paddy husk (Group I), paddy straw (Group II), pine leaves (Group III), and combination of paddy straw and pine leaves (Group IV), each having 30 chicks with 3 replicates of 10 chicks each. Chicks were reared under intensive conditions in houses that have a semi-controlled environment, with optimum temperature and adequate ventilation. Food and water were provided as per NRC (1994) requirement. Results: The average body weight after 6 weeks of the experiment was 2018.83±31.11, 1983.80±33.27, 2007.36±35.73, and 1938.43±36.35 g. The bedding type had no significant effect on the carcass characteristics viz. evisceration rate and proportion of cut-up parts of the carcass except giblet yield. The experiment suggested that performance of broiler chicks reared on paddy straw and pine leaves as litter material, had improved body weight and feed conversion ratio as compared to rearing on paddy husk as bedding material. Bacterial count, parasitic load and the N, P, K value of manure of different bedding material shows no significant difference. Conclusion: Pine leaves have a potential to be used as an alternative source of litter material to economize poultry production in a sustainable way, so as to make poultry farming as a profitable entrepreneur. PMID:27047021

Occurrence of commonly used pesticides in personal air samples and their associated health risk among paddy farmers.

PubMed

Hamsan, Hazwanee; Ho, Yu Bin; Zaidon, Siti Zulfa; Hashim, Zailina; Saari, Nazamid; Karami, Ali

2017-12-15

Tanjung Karang, Selangor, is widely known for its paddy cultivation activity and hosts the third largest paddy field in Malaysia. Pesticides contamination in agriculture fields has become an unavoidable problem, as pesticides are used to increase paddy productivity and reduce plant disease. Human exposure to agrichemicals is common and could results in both acute and chronic health effects, such as acute and chronic neurotoxicity. This study aims to determine the concentrations of commonly used pesticides (azoxystrobin, buprofezin, chlorantraniliprole, difenoconazole, fipronil, imidacloprid, isoprothiolane, pretilachlor, propiconazole, pymetrozine, tebuconazole, tricyclazole, and trifloxystrobin) in personal air samples and their associated health risks among paddy farmers. Eighty-three farmers from Tangjung Karang, Selangor were involved in this study. A solid sorbent tube was attached to the farmer's breathing zone with a clip, and an air pump was fastened to the belt to collect personal air samples. Pesticides collected in the XAD-2 resin were extracted with acetone, centrifuged, concentrated via nitrogen blowdown and reconstituted with 1mL of 3:1 ultrapure water/HPLC-grade methanol solution. The extract was analyzed using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The target compounds were detected with a maximum concentration reaching up to 462.5ngm -3 (fipronil). The hazard quotient (HQ) was less than 1 and the hazard index (HI) value was 3.86×10 -3 , indicating that the risk of pesticides related diseases was not significant. The lifetime cancer risk (LCR) for pymetrozine was at an acceptable level (LCR<10 -6 ) with 4.10×10 -8 . The results reported in this study can be beneficial in terms of risk management within the agricultural community. Copyright © 2017 Elsevier B.V. All rights reserved.

Partitioning of arsenic in soil-crop systems irrigated using groundwater: a case study of rice paddy soils in southwestern Taiwan.

PubMed

Hsu, Wen-Ming; Hsi, Hsing-Cheng; Huang, You-Tuan; Liao, Chien-Sen; Hseu, Zeng-Yei

2012-02-01

The accumulation of As in rice due to groundwater irrigation in paddy fields represents a serious health hazard in South and Southeast Asia. In Taiwan, the fate of As in long-term irrigated paddy fields is poorly understood. Groundwater, surface soil, and rice samples were collected from a paddy field that was irrigated with As-containing groundwater in southwestern Taiwan. The purpose of this study is to elucidate the source and sink of As in the paddy field by comparing the As fractions in the soils that were obtained by a sequential extraction procedure (SEP) with the As uptake of rice. The risks associated with eating rice from the field can thus be better understood. The concentration of As in groundwater varied with time throughout the growing seasons of rice, but always exceeded the permitted maximum (10 μg L(-1)) for drinking water by the WHO. The As concentration increased with the concentration of Fe in the groundwater, supporting the claim that a large amount of As was concentrated in the Fe flocs collected from the internal wall of the groundwater pump. The results of the SEP revealed that As bound with amorphous and crystalline hydrous oxides exhibited high availability in the soils. The root of rice accumulated the largest amount of As, followed by the straw, husk, and grain. Although the As concentration in the rice grain was less than 1.0 mg kg(-1), the estimated intake level was close to the maximum tolerable daily intake of As, as specified by the WHO. Copyright © 2011 Elsevier Ltd. All rights reserved.

Quantifying differences in water and carbon cycling between paddy and rainfed rice (Oryza sativa L.) by flux partitioning

PubMed Central

Nay‐Htoon, Bhone; Xue, Wei; Lindner, Steve; Cuntz, Matthias; Ko, Jonghan; Tenhunen, John; Werner, Christiane

2018-01-01

Agricultural crops play an important role in the global carbon and water cycle. Global climate change scenarios predict enhanced water scarcity and altered precipitation pattern in many parts of the world. Hence, a mechanistic understanding of water fluxes, productivity and water use efficiency of cultivated crops is of major importance, i.e. to adapt management practices. We compared water and carbon fluxes of paddy and rainfed rice by canopy scale gas exchange measurements, crop growth, daily evapotranspiration, transpiration and carbon flux modeling. Throughout a monsoon rice growing season, soil evaporation in paddy rice contributed strongly to evapotranspiration (96.6% to 43.3% from initial growth to fully developed canopy and amounted to 57.9% of total water losses over the growing seasons. Evaporation of rainfed rice was significantly lower (by 65% on average) particularly before canopy closure. Water use efficiency (WUE) was significantly higher in rainfed rice both from an agronomic (WUEagro, i.e. grain yield per evapotranspiration) and ecosystem (WUEeco, i.e. gross primary production per evapotranspiration) perspective. However, our results also show that higher WUE in rainfed rice comes at the expense of higher respiration losses compared to paddy rice (26% higher on average). Hence, suggestions on water management depend on the regional water availability (i.e. Mediterranean vs. Monsoon climate) and the balance between higher respiratory losses versus a potential reduction in CH4 and other greenhouse gas emissions. Our results suggest that a shift from rainfed/unsaturated soil to waterlogged paddy conditions after closure of the rice canopy might be a good compromise towards a sustainable use of water while preserving grain yield, particularly for water-limited production areas. PMID:29624613

A simple evaluation of soil quality of waterlogged purple paddy soils with different productivities.

PubMed

Liu, Zhanjun; Zhou, Wei; Lv, Jialong; He, Ping; Liang, Guoqing; Jin, Hui

2015-01-01

Evaluation of soil quality can be crucial for designing efficient farming systems and ensuring sustainable agriculture. The present study aimed at evaluating the quality of waterlogged purple paddy soils with different productivities in Sichuan Basin. The approach involved comprehensive analyses of soil physical and chemical properties, as well as enzyme activities and microbial community structure measured by phospholipid fatty acid analysis (PLFA). A total of 36 soil samples were collected from four typical locations, with 12 samples representing high productivity purple paddy soil (HPPS), medium productivity purple paddy soil (MPPS) and low productivity purple paddy soil (LPPS), respectively. Most measured soil properties showed significant differences (P ≤ 0.05) among HPPS, MPPS and LPPS. Pearson correlation analysis and principal component analysis were used to identify appropriate soil quality indicators. A minimum data set (MDS) including total nitrogen (TN), available phosphorus (AP), acid phosphatase (ACP), total bacteria (TB) and arbuscular mycorrhizal fungi was established and accounted for 82.1% of the quality variation among soils. A soil quality index (SQI) was developed based on the MDS method, whilst HPPS, MPPS and LPPS received mean SQI scores of 0.725, 0.536 and 0.425, respectively, with a ranking of HPPS > MPPS > LPPS. HPPS showed relatively good soil quality characterized by optimal nutrient availability, enzymatic and microbial activities, but the opposite was true of LPPS. Low levels of TN, AP and soil microbial activities were considered to be the major constraints limiting the productivity in LPPS. All soil samples collected were rich in available N, K, Si and Zn, but deficient in available P, which may be the major constraint for the studied regions. Managers in our study area should employ more appropriate management in the LPPS to improve its rice productivity, and particularly to any potential limiting factor.

Effect of Elevated CO2 Concentration, Elevated Temperature and No Nitrogen Fertilization on Methanogenic Archaeal and Methane-Oxidizing Bacterial Community Structures in Paddy Soil.

PubMed

Liu, Dongyan; Tago, Kanako; Hayatsu, Masahito; Tokida, Takeshi; Sakai, Hidemitsu; Nakamura, Hirofumi; Usui, Yasuhiro; Hasegawa, Toshihiro; Asakawa, Susumu

2016-09-29

Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions.

Sources of atmospheric methane - Measurements in rice paddies and a discussion

NASA Technical Reports Server (NTRS)

Cicerone, R. J.; Shetter, J. D.

1981-01-01

Field measurements of methane fluxes from rice paddies, fresh water lakes, and saltwater marshes have been made to infer estimates of the size of these sources of atmospheric methane. The rice-paddy measurements, the first of their kind, show that the principal means of methane escape is through the plants themselves as opposed to transport across the water-air interface via bubbles or molecular diffusion. Nitrogen-fertilized plants release much more methane than unfertilized plants but even these measured rates are only one fourth as large as those inferred earlier by Koyama (1963, 1964) and on which all global extrapolations have been based to date. Measured methane fluxes from lakes and marshes are also compared to similar earlier data and it is found that extant data and flux-measurement methods are insufficient for reliable global extrapolations.

Direct seeding of brushbox, lemon-gum eucalyptus, and cluster pine in Hawaii

Treesearch

Gerald A. Walters

1969-01-01

Seeds of brushbox, lemon-gum eucalyptus, and cluster pine were sown in separate seed spots on the Mokuleia Forest Reserve, Oahu. Half the seed spots were mulched. After 1 year, only two brushbox seed spots were stocked; lemon-gum eucalyptus had significantly (5 percent level) more seed spots stocked in the mulched plots; cluster pine had significantly less. These two...

Method of aeration disinfecting and drying grain in bulk and pretreating seeds and a transverse blow silo grain dryer therefor

DOEpatents

Danchenko, Vitaliy G [Dnipropetrovsk, UA; Noyes, Ronald T [Stillwater, OK; Potapovych, Larysa P [Dnipropetrovsk, UA

2012-02-28

Aeration drying and disinfecting grain crops in bulk and pretreating seeds includes passing through a bulk of grain crops and seeds disinfecting and drying agents including an ozone and air mixture and surrounding air, subdividing the disinfecting and drying agents into a plurality of streams spaced from one another in a vertical direction, and passing the streams at different heights through levels located at corresponding heights of the bulk of grain crops and seeds transversely in a substantially horizontal direction.

Risk assessment of Cd polluted paddy soils in the industrial and township areas in Hunan, Southern China.

PubMed

Wang, Meie; Chen, Weiping; Peng, Chi

2016-02-01

Cadmium (Cd) contamination in rice in Youxian, Hunan, China is a major environmental health concern. In order to reveal the Cd contamination in rice and paddy soils and the health risks to the population consuming the local rice grain, field surveys were conducted in eight towns in Youxian, China. The Cd contents of paddy soils averaged 0.228-1.91 mg kg(-1), 90% exceeding the allowable limit of 0.3 mg kg(-1) stipulated by the China Soil Environmental Quality Standards. Low average pH values (for air dried oxidized soils) ranging from 4.98 to 6.02 in paddy soil were also found. More than seventy percent (39 of 53) of the grain samples exceeded the maximum safe concentration of Cd, 0.2 mg kg(-1) on a dry weight basis. Considering the high consumption of local rice (339 g capita(-1) DW d(-1)) and Cd levels measured, dietary ingestion of 78% of the sampled rice grains would have adverse health risks because the intake exposure of Cd was greater than the JECFA recommended exposures, 0.8 µg Cd BW kg(-1) day(-1) or 25 µg Cd BW kg(-1) month(-1). Copyright © 2015 Elsevier Ltd. All rights reserved.

[Effects of land-use conversion from double rice cropping to vegetables on CO2 and CH4 fluxes in southern China].

PubMed

Yuan, Ye; Liu, Chang-hong; Dai, Xiao-qin; Wang, Hui-min

2015-01-01

In this study, the CO2 and CH4 fluxes in the first year after land use conversion from paddy rice to vegetables were measured by static opaque chamber and gas-chromatograph (GC) method to investigate the land conversion effects on soil CO2 and CH4 emissions. Our results showed that the differences in CO2 fluxes depended on the vegetable types, growing status and seasons. The CO2 flux from the vegetable field was greater than that from the paddy rice field when cowpea was planted, but was lower when pepper was planted. The CH4 flux significantly decreased from 6.96 mg C . m-2 . h-1 to -0.004 mg C . m-2 . h-1 with the land use conversion from rice to vegetables.The net carbon absorption ( CO2 + CH4) of the vegetable fields was 543 kg C . hm-2, significantly lower than that (3641 kg C . hm-2) of the rice paddies. However, no significant difference was found in their global warming impact. In addition, soil carbon content increased in vegetable fields compared to the paddy rice fields after a year of conversion, especially in the 10-20 cm soil layer.

Deep rooting conferred by DEEPER ROOTING 1 enhances rice yield in paddy fields.

PubMed

Arai-Sanoh, Yumiko; Takai, Toshiyuki; Yoshinaga, Satoshi; Nakano, Hiroshi; Kojima, Mikiko; Sakakibara, Hitoshi; Kondo, Motohiko; Uga, Yusaku

2014-07-03

To clarify the effect of deep rooting on grain yield in rice (Oryza sativa L.) in an irrigated paddy field with or without fertilizer, we used the shallow-rooting IR64 and the deep-rooting Dro1-NIL (a near-isogenic line homozygous for the Kinandang Patong allele of DEEPER ROOTING 1 (DRO1) in the IR64 genetic background). Although total root length was similar in both lines, more roots were distributed within the lower soil layer of the paddy field in Dro1-NIL than in IR64, irrespective of fertilizer treatment. At maturity, Dro1-NIL showed approximately 10% higher grain yield than IR64, irrespective of fertilizer treatment. Higher grain yield of Dro1-NIL was mainly due to the increased 1000-kernel weight and increased percentage of ripened grains, which resulted in a higher harvest index. After heading, the uptake of nitrogen from soil and leaf nitrogen concentration were higher in Dro1-NIL than in IR64. At the mid-grain-filling stage, Dro1-NIL maintained higher cytokinin fluxes from roots to shoots than IR64. These results suggest that deep rooting by DRO1 enhances nitrogen uptake and cytokinin fluxes at late stages, resulting in better grain filling in Dro1-NIL in a paddy field in this study.

[Control effects of rice-duck farming and other weed management strategies on weed communities in paddy fields].

PubMed

Wei, Shouhui; Qiang, Sheng; Ma, Bo; Wei, Jiguang; Chen, Jianwei; Wu, Jianqiang; Xie, Tongzhou; Shen, Xiaokun

2005-06-01

By the methods of community ecology, field studies were conducted to evaluate the control effects of three weed management strategies, i. e., rice-duck farming (RD), manual weeding (MW) and chemical weeding (CW), on the weed communities in paddy fields. The results showed that under rice-duck farming, the weed density in paddy fields decreased significantly, and the control effects on dominant weed species such as Monochoria vaginalis, Cyperus difformis, Sagittaria pygmaea were all above 95%, with an overall effect higher than CW and MW. Under RD, the species richness and Shannon-Wiener diversity indices decreased slightly, while Pielou community evenness indices increased markedly, indicating that the species composition of weed community was greatly improved, and the infestation of former dominant weed species was reduced. The structure of weed communities in paddy fields varied with different weed management strategies, e. g., under RD, Lindernia procumbens, Cyperus difformis and Fimbristylis miliacea constituted the major weed community, and the Whittaker index was significant higher than that of CW, MW and CK, which indicated that rice-duck farming had a greater effect on the structure of the weed communities. The same conclusion could be drawn from Sorensen's similarity indices and cluster analysis with Sorensen's index as the distance measurement.

Rice (Oryza sativa L) plantation affects the stability of biochar in paddy soil.

PubMed

Wu, Mengxiong; Feng, Qibo; Sun, Xue; Wang, Hailong; Gielen, Gerty; Wu, Weixiang

2015-05-05

Conversion of rice straw into biochar for soil amendment appears to be a promising method to increase long-term carbon sequestration and reduce greenhouse gas (GHG) emissions. The stability of biochar in paddy soil, which is the major determining factor of carbon sequestration effect, depends mainly on soil properties and plant functions. However, the influence of plants on biochar stability in paddy soil remains unclear. In this study, bulk and surface characteristics of the biochars incubated without rice plants were compared with those incubated with rice plants using a suite of analytical techniques. Results showed that although rice plants had no significant influence on the bulk characteristics and decomposition rates of the biochar, the surface oxidation of biochar particles was enhanced by rice plants. Using (13)C labeling we observed that rice plants could significantly increase carbon incorporation from biochar into soil microbial biomass. About 0.047% of the carbon in biochar was incorporated into the rice plants during the whole rice growing cycle. These results inferred that root exudates and transportation of biochar particles into rice plants might decrease the stability of biochar in paddy soil. Impact of plants should be considered when predicting carbon sequestration potential of biochar in soil systems.

Abundance, composition and activity of denitrifier communities in metal polluted paddy soils

PubMed Central

Liu, Yuan; Liu, Yongzhuo; Zhou, Huimin; Li, Lianqing; Zheng, Jinwei; Zhang, Xuhui; Zheng, Jufeng; Pan, Genxing

2016-01-01

Denitrification is one of the most important soil microbial processes leading to the production of nitrous oxide (N2O). The potential changes with metal pollution in soil microbial community for N2O production and reduction are not well addressed. In this study, topsoil samples were collected both from polluted and non-polluted rice paddy fields and denitrifier communities were characterized with molecular fingerprinting procedures. All the retrieved nirK sequences could be grouped into neither α- nor β- proteobacteria, while most of the nosZ sequences were affiliated with α-proteobacteria. The abundances of the nirK and nosZ genes were reduced significantly in the two polluted soils. Thus, metal pollution markedly affected composition of both nirK and nosZ denitrifiers. While the total denitrifying activity and N2O production rate were both reduced under heavy metal pollution of the two sites, the N2O reduction rate showed no significant change. These findings suggest that N2O production activity could be sensitive to heavy metal pollution, which could potentially lead to a decrease in N2O emission in polluted paddies. Therefore, metal pollution could have potential impacts on soil N transformation and thus on N2O emission from paddy soils. PMID:26739424

[Effects of biochar application on greenhouse gas emission from paddy soil and its physical and chemical properties].

PubMed

Liu, Yu-xue; Wang, Yao-feng; Lü, Hao-hao; Chen, Yi; Tang, Xu; Wu, Chun-yan; Zhong, Zhe-ke; Yang, Sheng-mao

2013-08-01

A field experiment was conducted to investigate the effects of rice straw returning and rice straw biochar and life rubbish biochar application on the greenhouse gas (CH4, CO2 and N2O) emission from paddy soil, its physical and chemical properties, and rice grain yield. Compared with rice straw returning, applying rice straw biochar decreased the cumulative CH4 and N2O emissions from paddy soil significantly by 64.2% - 78.5% and 16.3% - 18.4%, respectively. Whether planting rice or not, the cumulative N2O emission from paddy soil under the applications of rice straw biochar and life rubbish biochar was decreased significantly, compared with that without biochar amendment. Under the condition of no rice planting, applying life rubbish biochar reduced the cumulative CO2 emission significantly by 25.3%. Rice straw biochar was superior to life rubbish biochar in improving soil pH and available potassium content. Both rice straw biochar and life rubbish biochar could increase the soil organic carbon content significantly, but had less effects on the soil bulk density, total nitrogen and available phosphorus contents, cation exchange capacity (CEC), and grain yield. It was suggested that compared with rice straw returning, straw biochar was more effective in improving rice grain yield.

Factors Related with CH4 and N2O Emissions from a Paddy Field: Clues for Management implications

PubMed Central

Wang, Chun; Lai, Derrick Y. F.; Sardans, Jordi; Wang, Weiqi; Zeng, Congsheng; Peñuelas, Josep

2017-01-01

Paddy fields are major sources of global atmospheric greenhouse gases, including methane (CH4) and nitrous oxide (N2O). The different phases previous to emission (production, transport, diffusion, dissolution in pore water and ebullition) despite well-established have rarely been measured in field conditions. We examined them and their relationships with temperature, soil traits and plant biomass in a paddy field in Fujian, southeastern China. CH4 emission was positively correlated with CH4 production, plant-mediated transport, ebullition, diffusion, and concentration of dissolved CH4 in porewater and negatively correlated with sulfate concentration, suggesting the potential use of sulfate fertilizers to mitigate CH4 release. Air temperature and humidity, plant stem biomass, and concentrations of soil sulfate, available N, and DOC together accounted for 92% of the variance in CH4 emission, and Eh, pH, and the concentrations of available N and Fe3+, leaf biomass, and air temperature 95% of the N2O emission. Given the positive correlations between CH4 emission and DOC content and plant biomass, reduce the addition of a carbon substrate such as straw and the development of smaller but higher yielding rice genotypes could be viable options for reducing the release of greenhouse gases from paddy fields to the atmosphere. PMID:28081161

Organic carbon and nitrogen availability determine bacterial community composition in paddy fields of the Indo-Gangetic plain.

PubMed

Kumar, Arvind; Rai, Lal Chand

2017-07-01

Soil quality is an important factor and maintained by inhabited microorganisms. Soil physicochemical characteristics determine indigenous microbial population and rice provides food security to major population of the world. Therefore, this study aimed to assess the impact of physicochemical variables on bacterial community composition and diversity in conventional paddy fields which could reflect a real picture of the bacterial communities operating in the paddy agro-ecosystem. To fulfill the objective; soil physicochemical characterization, bacterial community composition and diversity analysis was carried out using culture-independent PCR-DGGE method from twenty soils distributed across eight districts. Bacterial communities were grouped into three clusters based on UPGMA cluster analysis of DGGE banding pattern. The linkage of measured physicochemical variables with bacterial community composition was analyzed by canonical correspondence analysis (CCA). CCA ordination biplot results were similar to UPGMA cluster analysis. High levels of species-environment correlations (0.989 and 0.959) were observed and the largest proportion of species data variability was explained by total organic carbon (TOC), available nitrogen, total nitrogen and pH. Thus, results suggest that TOC and nitrogen are key regulators of bacterial community composition in the conventional paddy fields. Further, high diversity indices and evenness values demonstrated heterogeneity and co-abundance of the bacterial communities.

Multi-year monitoring of paddy rice planting area in Northeast China using MODIS time series data.

PubMed

Shi, Jing-jing; Huang, Jing-feng; Zhang, Feng

2013-10-01

The objective of this study was to investigate the tempo-spatial distribution of paddy rice in Northeast China using moderate resolution imaging spectroradiometer (MODIS) data. We developed an algorithm for detection and estimation of the transplanting and flooding periods of paddy rice with a combination of enhanced vegetation index (EVI) and land surface water index with a central wavelength at 2130 nm (LSWI2130). In two intensive sites in Northeast China, fine resolution satellite imagery was used to validate the performance of the algorithm at pixel and 3×3 pixel window levels, respectively. The commission and omission errors in both of the intensive sites were approximately less than 20%. Based on the algorithm, annual distribution of paddy rice in Northeast China from 2001 to 2009 was mapped and analyzed. The results demonstrated that the MODIS-derived area was highly correlated with published agricultural statistical data with a coefficient of determination (R(2)) value of 0.847. It also revealed a sharp decline in 2003, especially in the Sanjiang Plain located in the northeast of Heilongjiang Province, due to the oversupply and price decline of rice in 2002. These results suggest that the approaches are available for accurate and reliable monitoring of rice cultivated areas and variation on a large scale.

Assessing the pollution risk of soil Chromium based on loading capacity of paddy soil at a regional scale

PubMed Central

Qu, Mingkai; Li, Weidong; Zhang, Chuanrong; Huang, Biao; Zhao, Yongcun

2015-01-01

The accumulation of a trace metal in rice grain is not only affected by the total concentration of the soil trace metal, but also by crop variety and related soil properties, such as soil pH, soil organic matter (SOM) and so on. However, these factors were seldom considered in previous studies on mapping the pollution risk of trace metals in paddy soil at a regional scale. In this study, the spatial nonstationary relationships between rice-Cr and a set of perceived soil properties (soil-Cr, soil pH and SOM) were explored using geographically weighted regression; and the relationships were then used for calculating the critical threshold (CT) of soil-Cr concentration that may ensure the concentration of rice-Cr being below the permissible limit. The concept of “loading capacity” (LC) for Cr in paddy soil was then defined as the difference between the CT and the real concentration of Cr in paddy soil, so as to map the pollution risk of soil-Cr to rice grain and assess the risk areas in Jiaxing city, China. Compared with the information of the concentration of the total soil-Cr, such results are more valuable for spatial decision making in reducing the accumulation of rice-Cr at a regional scale. PMID:26675587

Assessing the pollution risk of soil Chromium based on loading capacity of paddy soil at a regional scale.

PubMed

Qu, Mingkai; Li, Weidong; Zhang, Chuanrong; Huang, Biao; Zhao, Yongcun

2015-12-17

The accumulation of a trace metal in rice grain is not only affected by the total concentration of the soil trace metal, but also by crop variety and related soil properties, such as soil pH, soil organic matter (SOM) and so on. However, these factors were seldom considered in previous studies on mapping the pollution risk of trace metals in paddy soil at a regional scale. In this study, the spatial nonstationary relationships between rice-Cr and a set of perceived soil properties (soil-Cr, soil pH and SOM) were explored using geographically weighted regression; and the relationships were then used for calculating the critical threshold (CT) of soil-Cr concentration that may ensure the concentration of rice-Cr being below the permissible limit. The concept of "loading capacity" (LC) for Cr in paddy soil was then defined as the difference between the CT and the real concentration of Cr in paddy soil, so as to map the pollution risk of soil-Cr to rice grain and assess the risk areas in Jiaxing city, China. Compared with the information of the concentration of the total soil-Cr, such results are more valuable for spatial decision making in reducing the accumulation of rice-Cr at a regional scale.

Screening optimal substrates from Erhai lakeside for Ottelia acuminata (Gagnep.) Dandy, an endangered submerged macrophyte in China.

PubMed

Chen, Shuqin; Chu, Zhaosheng; Zhou, Yunqiao; Li, Qifeng; Wang, Tieyu

2018-05-08

Because of the unstable hydrodynamic conditions in the wild, the endangered aquatic plant should be cultivated first in constructed wetlands for the protection and expansion of germplasm resources. Ottelia acuminata (Gagnep.) Dandy has become extinct in Erhai Lake, Yunnan province, China. In order to optimize substrates for this species to artificial cultivation, the native substrate (sandy soils) and the other three representative ones (red paddy soils, alluvial paddy soils, and purple paddy soils) collected from Erhai lakeside were applied to cultivate O. acuminata for 50 days. Multi indicators, such as antioxidant enzymes activity, malondialdehyde and chlorophyll-α concentration, and relative growth rate of O. acuminata, were discussed and statistically analyzed to classify the substrates. The results suggested that even disregarding the physiology significance of these indicators, hierarchical clustering analysis had high efficiency on optimizing substrates. Although various single indexes suggested different optimal substrates for macrophyte growth, red paddy soil was never excluded out the optimal substrate classes. Further study is needed to assess the substrates optimization functionalities of these indicators. This study offers amounts of physiology data and an effective method to optimize substrates of O. acuminata. It is helpful for environmental scientists and ecological engineers to conduct the similar study on endangered species.

Rice (Oryza sativa L) plantation affects the stability of biochar in paddy soil

PubMed Central

Wu, Mengxiong; Feng, Qibo; Sun, Xue; Wang, Hailong; Gielen, Gerty; Wu, Weixiang

2015-01-01

Conversion of rice straw into biochar for soil amendment appears to be a promising method to increase long-term carbon sequestration and reduce greenhouse gas (GHG) emissions. The stability of biochar in paddy soil, which is the major determining factor of carbon sequestration effect, depends mainly on soil properties and plant functions. However, the influence of plants on biochar stability in paddy soil remains unclear. In this study, bulk and surface characteristics of the biochars incubated without rice plants were compared with those incubated with rice plants using a suite of analytical techniques. Results showed that although rice plants had no significant influence on the bulk characteristics and decomposition rates of the biochar, the surface oxidation of biochar particles was enhanced by rice plants. Using 13C labeling we observed that rice plants could significantly increase carbon incorporation from biochar into soil microbial biomass. About 0.047% of the carbon in biochar was incorporated into the rice plants during the whole rice growing cycle. These results inferred that root exudates and transportation of biochar particles into rice plants might decrease the stability of biochar in paddy soil. Impact of plants should be considered when predicting carbon sequestration potential of biochar in soil systems. PMID:25944542

Soil microbial C:N ratio is a robust indicator of soil productivity for paddy fields

NASA Astrophysics Data System (ADS)

Li, Yong; Wu, Jinshui; Shen, Jianlin; Liu, Shoulong; Wang, Cong; Chen, Dan; Huang, Tieping; Zhang, Jiabao

2016-10-01

Maintaining good soil productivity in rice paddies is important for global food security. Numerous methods have been developed to evaluate paddy soil productivity (PSP), most based on soil physiochemical properties and relatively few on biological indices. Here, we used a long-term dataset from experiments on paddy fields at eight county sites and a short-term dataset from a single field experiment in southern China, and aimed at quantifying relationships between PSP and the ratios of carbon (C) to nutrients (N and P) in soil microbial biomass (SMB). In the long-term dataset, SMB variables generally showed stronger correlations with the relative PSP (rPSP) compared to soil chemical properties. Both correlation and variation partitioning analyses suggested that SMB N, P and C:N ratio were good predictors of rPSP. In the short-term dataset, we found a significant, negative correlation of annual rice yield with SMB C:N (r = -0.99), confirming SMB C:N as a robust indicator for PSP. In treatments of the short-term experiment, soil amendment with biochar lowered SMB C:N and improved PSP, while incorporation of rice straw increased SMB C:N and reduced PSP. We conclude that SMB C:N ratio does not only indicate PSP but also helps to identify management practices that improve PSP.

Soil quality evolution after land use change from paddy soil to vegetable land.

PubMed

Cao, Z H; Huang, J F; Zhang, C S; Li, A F

2004-01-01

A survey was done in 15 typical villages, 150 soil and 86 vegetable plant samples were taken in Jiaxin prefecture of the Taihu Lake region, northern Zhejian province. Results indicate that after 15-20 years land use changed from the paddy rice-wheat (or oilseed rape) double cropping system, to a continuous vegetable land has caused soil quality dramatic change. (1) Acidification: average soil pH was 5.4; about 61% of total samples were pH < 5.5. It was 0.9 units lower than 10 years ago with same upland vegetable cultivation and was 1.2 units lower than soil pH of paddy rice-wheat (or oilseed rape) rotation. (2) Fertilizer salt accumulation: the average salt content was 0.28%, among these about 36.2% of the total samples contained more than 0.3%. (3) Nitrate N and available phosphorus (P) over accumulation: on average it was 279 mg NO3-N/kg, and 45-115 mg P/kg. Nitrate N four times higher and available P 4-10 times more than it is in present paddy rice-wheat rotation soils respectively. This has caused wide concern because of possible groundwater and well drinking water pollution by leached nitrate N and the P losses to water by runoff from vegetable lands induce surface water eutrophication.

Multi-year monitoring of paddy rice planting area in Northeast China using MODIS time series data*

PubMed Central

Shi, Jing-jing; Huang, Jing-feng; Zhang, Feng

2013-01-01

The objective of this study was to investigate the tempo-spatial distribution of paddy rice in Northeast China using moderate resolution imaging spectroradiometer (MODIS) data. We developed an algorithm for detection and estimation of the transplanting and flooding periods of paddy rice with a combination of enhanced vegetation index (EVI) and land surface water index with a central wavelength at 2 130 nm (LSWI2130). In two intensive sites in Northeast China, fine resolution satellite imagery was used to validate the performance of the algorithm at pixel and 3×3 pixel window levels, respectively. The commission and omission errors in both of the intensive sites were approximately less than 20%. Based on the algorithm, annual distribution of paddy rice in Northeast China from 2001 to 2009 was mapped and analyzed. The results demonstrated that the MODIS-derived area was highly correlated with published agricultural statistical data with a coefficient of determination (R 2) value of 0.847. It also revealed a sharp decline in 2003, especially in the Sanjiang Plain located in the northeast of Heilongjiang Province, due to the oversupply and price decline of rice in 2002. These results suggest that the approaches are available for accurate and reliable monitoring of rice cultivated areas and variation on a large scale. PMID:24101210

Analysis of soybean leaf metabolism and seed coat transcriptome reveal sink strength is maintained under abiotic stress conditions

USDA-ARS?s Scientific Manuscript database

The seed coat is a vital tissue for directing the flow of photosynthate from source leaves to the embryo and cotyledons during seed development. By forming a sucrose gradient, the seed coat promotes transport of sugars from source leaves to seeds, thereby establishing sink strength. Understanding th...

Low cost, high tech seed cleaning

Treesearch

Robert P. Karrfalt

2013-01-01

Clean seeds are a great asset in native plant restoration. However, seed cleaning equipment is often too costly for many small operations. This paper introduces how several tools and materials intended for other purposes can be used directly or made into simple machines to clean seeds.

Open-pit coal-mining effects on rice paddy soil composition and metal bioavailability to Oryza sativa L. plants in Cam Pha, northeastern Vietnam.

PubMed

Martinez, Raul E; Marquez, J Eduardo; Hòa, Hoàng Thị Bích; Gieré, Reto

2013-11-01

This study quantified Cd, Pb, and Cu content, and the soil-plant transfer factors of these elements in rice paddies within Cam Pha, Quang Ninh province, northeastern Vietnam. The rice paddies are located at a distance of 2 km from the large Coc Sau open-pit coal mine. Electron microprobe analysis combined with backscattered electron imaging and energy-dispersive spectroscopy revealed a relatively high proportion of carbon particles rimmed by an iron sulfide mineral (probably pyrite) in the quartz-clay matrix of rice paddy soils at 20-30 cm depth. Bulk chemical analysis of these soils revealed the presence of Cd, Cu, and Pb at concentrations of 0.146±0.004, 23.3±0.1, and 23.5±0.1 mg/kg which exceeded calculated background concentrations of 0.006±0.004, 1.9±0.5, and 2.4±1.5 mg/kg respectively at one of the sites. Metals and metalloids in Cam Pha rice paddy soils, including As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn, were found in concentrations ranging from 0.2±0.1 to 140±3 mg/kg, which were in close agreement with toxic metal contents in mine tailings and Coc Sau coal samples, suggesting mining operations as a major cause of paddy soil contamination. Native and model Oryza sativa L. rice plants were grown in the laboratory in a growth medium to which up to 1.5 mg/kg of paddy soil from Cam Pha was added to investigate the effects on plant growth. A decrease in growth by up to 60% with respect to a control sample was found for model plants, whereas a decrease of only 10% was observed for native (Nep cai hoa vang variety) rice plants. This result suggests an adaptation of native Cam Pha rice plants to toxic metals in the agricultural lands. The Cd, Cu, and Pb contents of the native rice plants from Cam Pha paddies exceeded permitted levels in foods. Cadmium and Pb were highest in the rice plant roots with concentrations of 0.84±0.02 and 7.7±0.3 mg/kg, suggesting an intake of these metals into the rice plant as shown, for example, by Cd and Pb concentrations of 0.09±0.01 and 0.10±0.04 mg/kg respectively in the rice grain endosperm. The adaptation of native rice plants, combined with bioaccumulation ratios of 1±0.6 to 1.4±0.7 calculated for Cd transfer to the rice grain endosperm, and maximum Cd transfer factors of 4.3±2.1 to the plant roots, strongly suggest a continuous input of some toxic metals from coal-mining operations to agricultural lands in the region of Cam Pha. In addition, our results imply a sustained absorption of metals by native rice plant varieties, which may lead to metal accumulation (e.g., Cd) in human organs and in turn to severe disease.

[Analytic methods for seed models with genotype x environment interactions].

PubMed

Zhu, J

1996-01-01

Genetic models with genotype effect (G) and genotype x environment interaction effect (GE) are proposed for analyzing generation means of seed quantitative traits in crops. The total genetic effect (G) is partitioned into seed direct genetic effect (G0), cytoplasm genetic of effect (C), and maternal plant genetic effect (Gm). Seed direct genetic effect (G0) can be further partitioned into direct additive (A) and direct dominance (D) genetic components. Maternal genetic effect (Gm) can also be partitioned into maternal additive (Am) and maternal dominance (Dm) genetic components. The total genotype x environment interaction effect (GE) can also be partitioned into direct genetic by environment interaction effect (G0E), cytoplasm genetic by environment interaction effect (CE), and maternal genetic by environment interaction effect (GmE). G0E can be partitioned into direct additive by environment interaction (AE) and direct dominance by environment interaction (DE) genetic components. GmE can also be partitioned into maternal additive by environment interaction (AmE) and maternal dominance by environment interaction (DmE) genetic components. Partitions of genetic components are listed for parent, F1, F2 and backcrosses. A set of parents, their reciprocal F1 and F2 seeds is applicable for efficient analysis of seed quantitative traits. MINQUE(0/1) method can be used for estimating variance and covariance components. Unbiased estimation for covariance components between two traits can also be obtained by the MINQUE(0/1) method. Random genetic effects in seed models are predictable by the Adjusted Unbiased Prediction (AUP) approach with MINQUE(0/1) method. The jackknife procedure is suggested for estimation of sampling variances of estimated variance and covariance components and of predicted genetic effects, which can be further used in a t-test for parameter. Unbiasedness and efficiency for estimating variance components and predicting genetic effects are tested by Monte Carlo simulations.

Effects of tetramine used for rodent control in direct seeding of Douglas-fir.

Treesearch

Elmer W. Shaw

1953-01-01

Rodent control is one of the most critical problems in reforestation by direct seeding. Several different types of rodenticides, baits, and repellents have been developed, but none have been completely satisfactory.

Characteristics of a Direct-Seeded Eastern White Pine Plantation on the Mid-Cumberland Plateau at Four Ages

Treesearch

Glendon W. Smalley; James M. Hollingsworth

1997-01-01

Growth and yield of a direct-seeded eastern white pine (Pinus strobus L.) plantation established in 1959 on a broad undulating sandstone upland (Landtype 1) are summarized. Average heights of dominant and codominant pines were 35,56,65, and 76 ft at ages 15,25,30, and 34 years, respectively. Equivalent site indices (base age 25 years from seed)...

[Effect of short-time drought process on denitrifying bacteria abundance and N2O emission in paddy soil].

PubMed

Lu, Jing; Liu, Jin-Bo; Sheng, Rong; Liu, Yi; Chen, An-Lei; Wei, Wen-Xue

2014-10-01

In order to investigate the impact of drying process on greenhouse gas emissions and denitrifying microorganisms in paddy soil, wetting-drying process was simulated in laboratory conditions. N2O flux, redox potential (Eh) were monitored and narG- and nosZ-containing denitrifiers abundances were determined by real-time PCR. N2O emission was significantly increased only 4 h after drying process began, and it was more than 6 times of continuous flooding (CF) at 24 h. In addition, narG and nosZ gene abundances were increased rapidly with the drying process, and N2O emission flux was significantly correlated with narG gene abundance (P < 0.01). Our results indicated that the narG-containing deniteifiers were the main driving microorganisms which caused the N2O emission in the short-time drought process in paddy soil.

Geochemical Transformation of Cadmium (Cd) from Creek to Paddy Fields in W Thailand

NASA Astrophysics Data System (ADS)

Kosolsaksakul, Peerapat; Graham, Margaret; Farmer, John

2013-04-01

Extensive Cd contamination of paddy soils in Tak Province, western Thailand, a consequence of Zn mining activities, was first established in 2005 and medical studies showed that the health of local communities was being impaired. Mae Tao, Tak Province, comprising many paddy fields and irrigation canals, has been selected for this study of the geochemical transformation of Cd from the contamination source in the mountainous region to the east of the study site through the community irrigation system to the paddy soils. The aim of this research is to (i) investigate the geochemical transformation of Cd as it is transported from the main irrigation creek through the canals and to the paddy fields, (ii) assess the availability of Cd to rice plants, which may be affected by both chemical and physical factors, and (iii) trial some practical treatments to minimise Cd concentrations in rice grains. Soils, irrigation canal sediments and water samples were collected during the dry season and at the onset of the rainy season. Rice samples were collected at harvesting time and samples of soil fertiliser were also obtained. Water samples were filtered, ultrafiltered and analysed by ICP-MS whilst sub-samples of dried, ground soils and sediments were first subjected to micro-wave assisted acid digestion (modified US EPA method 3052). XRD and SEM-EDX methods were used for mineralogical characterisation and selective chemical extractions have assisted in the characterisation of solid phase Cd associations. Soil Cd concentrations were in the range 2.5-87.6 µg g-1, with higher values being obtained for fields furthest from the main creek. Although current irrigation water Cd inputs are low (mean 1.9 μg L-1; flood period), high loads of suspended particles still contribute additional Cd (4.2-9.8 µg L-1) to the paddy fields. For bioavailability assessment by a 3-step BCR sequential extraction, 70-90% Cd was in the exchangeable; HOAc-extractable fraction. That indicated that most of the Cd was in water soluble, exchangeable and carbonate-bound forms. For the fields with highest Cd concentration, SEM-EDX analysis identified two forms of Cd, i.e. Cd-Clay and Cd-CaCO3, in good agreement with the sequential extraction data. The predominance of easily extractable forms in the paddy field soils suggests that Cd may be readily absorbed by the rice plants. After harvesting, the Cd concentration in rice grains ranged from 0.05-4.0 µg g-1 and the concentration trends across the group of 18 fields matched well with the soil Cd data. Rice from nine out of the 18 fields contained Cd at greater than the safe level of 0.4 µg g-1.

First flush characteristics of rainfall runoff from a paddy field in the Taihu Lake watershed, China.

PubMed

Li, Songmin; Wang, Xiaoling; Qiao, Bin; Li, Jiansheng; Tu, Jiamin

2017-03-01

Nonpoint storm runoff remains a major threat to surface water quality in China. As a paddy matures, numerous fertilizers are needed, especially in the rainy seasons; the concentration of nitrogen and phosphorus in rainfall runoff from farmland is much higher than at other times, and this poses a great threat to water bodies and is the main reason for water eutrophication, especially in high concentration drainages. To date, most studies regarding the characteristics of pollutants in rainfall runoff have mainly been concentrated on urban runoff and watershed runoff; therefore, it is particularly important to investigate the characteristics of nitrogen and phosphorus loss in rainfall runoff from paddy fields. To study the characteristics of nitrogen and phosphorus loss and whether the first flush effect exists, continuous monitoring of the rainfall runoff process of six rainfall events was conducted in 2013, of which four rainfall events during storm, high, middle, and low intensity rainfalls were analyzed, and runoff and quality parameters, such as suspended solids (SS), total nitrogen (TN), ammonium nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 - -N), total phosphorus (TP), and phosphate (PO 4 3- -P), were analyzed to determine the relationship between runoff and water quality. The paddy field is located north of Wuxi Lake Basin along the Hejia River upstream in Zhoutie town, Yixing city. An analysis of the load distribution during rainfall runoff was conducted. Event mean concentration (EMC) was used to evaluate the pollution situation of the paddy field's rainfall runoff. A curve of the dimensionless normalized cumulative load (L) vs. normalized cumulative flow (F) (L-F curve), the probability of the mass first flush (MFFn), and the pollutants carried by the initial 25% of runoff (FF 25 ) were used to analyze the first flush effect of the paddy field runoff, and different contaminants show different results: the concentration of nitrogen and phosphorus fluctuate and follow a similar trend as runoff changes, NO 3 - -N concentration is lower in the early part of runoff and higher in the later, and TP mainly occurs in the particle state in storm runoff and mainly in the dissolved state when the rainfall intensity is smaller. Nitrogen and phosphorus losses from paddy fields are closely related to the average rainfall intensity and the max rainfall intensity, and the runoff loss of nitrogen and phosphorus is more severe when the rainfall intensity is large. Based on an analysis of multiple methodologies, TN and NH 4 + -N show a certain degree of a first flush effect, whereas the first flush effect of TP is not obvious. The first flush effect of SS is obvious in larger intensity rainfall and shows a slight secondary flush effect in smaller rainfall events.

Emergent aquatics: stand establishment, management, and species screening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pratt, D.C.; Andrews, N.J.; Dubbe, D.R.

1982-11-01

Several emergent aquatic species have been identified as potential biomass crops, including Typha spp. (cattail), Scirpus spp. (rush), Sparganium spp. (bur reed), and Phragmites (reed). This report discusses first year results from studies of stand establishment and management, Typha nutrient requirements, wetland species yield comparisons, and Typha micropropagation. In a comparison of the relative effectiveness of seed, seedlings, and rhizomes for stand establishment, rhizomes appeared to be more consistent and productive under a wire variety of conditions. Both rhizomes and seedling established plots grew successfully on excavated peatland sites. First season results from a multiyear fertilizer rate experiment indicate thatmore » fertilizer treatment resulted in significantly increased tissue nutrient concentrations which should carry over into subsequent growing seasons. Shoot density and belowground dry weight were also significantly increased by phosphorus + potassium and potassium applications, respectively. First season yields of selected wetland species from managed paddies generally were comparable to yields reported from natural stands. Several particularly productive clones of Typha spp. have been identified. A method of establishing Typha in tissue culture is described.« less

Mountain-climbing bears protect cherry species from global warming through vertical seed dispersal.

PubMed

Naoe, Shoji; Tayasu, Ichiro; Sakai, Yoichiro; Masaki, Takashi; Kobayashi, Kazuki; Nakajima, Akiko; Sato, Yoshikazu; Yamazaki, Koji; Kiyokawa, Hiroki; Koike, Shinsuke

2016-04-25

In a warming climate, temperature-sensitive plants must move toward colder areas, that is, higher latitude or altitude, by seed dispersal [1]. Considering that the temperature drop with increasing altitude (-0.65°C per 100 m altitude) is one hundred to a thousand times larger than that of the equivalent latitudinal distance [2], vertical seed dispersal is probably a key process for plant escape from warming temperatures. In fact, plant geographical distributions are tracking global warming altitudinally rather than latitudinally, and the extent of tracking is considered to be large in plants with better-dispersed traits (e.g., lighter seeds in wind-dispersed plants) [1]. However, no study has evaluated vertical seed dispersal itself due to technical difficulty or high cost. Here, we show using a stable oxygen isotope that black bears disperse seeds of wild cherry over several hundred meters vertically, and that the dispersal direction is heavily biased towards the mountain tops. Mountain climbing by bears following spring-to-summer plant phenology is likely the cause of this biased seed dispersal. These results suggest that spring- and summer-fruiting plants dispersed by animals may have high potential to escape global warming. Our results also indicate that the direction of vertical seed dispersal can be unexpectedly biased, and highlight the importance of considering seed dispersal direction to understand plant responses to past and future climate change. Copyright © 2016 Elsevier Ltd. All rights reserved.

Organophosphorus and carbamate pesticide residues detected in water samples collected from paddy and vegetable fields of the Savar and Dhamrai Upazilas in Bangladesh.

PubMed

Chowdhury, Md Alamgir Zaman; Banik, Sanjoy; Uddin, Borhan; Moniruzzaman, Mohammed; Karim, Nurul; Gan, Siew Hua

2012-09-11

Several types of organophosphorous and carbamate pesticides have been used extensively by the farmers in Bangladesh during the last few decades. Twenty seven water samples collected from both paddy and vegetable fields in the Savar and Dhamrai Upazilas in Bangladesh were analyzed to determine the occurrence and distribution of organo-phosphorus (chlorpyrifos, malathion and diazinon) and carbamate (carbaryl and carbofuran) pesticide residues. A high performance liquid chromatograph instrument equipped with a photodiode array detector was used to determine the concentrations of these pesticide residues. Diazinon and carbofuran were detected in water samples collected from Savar Upazila at 0.9 μg/L and 198.7 μg/L, respectively. Malathion was also detected in a single water sample at 105.2 μg/L from Dhamrai Upazila. Carbaryl was the most common pesticide detected in Dhamrai Upazila at 14.1 and 18.1 μg/L, while another water sample from Dhamrai Upazila was contaminated with carbofuran at 105.2 μg/L. Chlorpyrifos was not detected in any sample. Overall, the pesticide residues detected were well above the maximum acceptable levels of total and individual pesticide contamination, at 0.5 and 0.1 μg/L, respectively, in water samples recommended by the European Economic Community (Directive 98/83/EC). The presence of these pesticide residues may be attributed by their intense use by the farmers living in these areas. Proper handling of these pesticides should be ensured to avoid direct or indirect exposure to these pesticides.

Seed filling in domesticated maize and rice depends on SWEET-mediated hexose transport

USDA-ARS?s Scientific Manuscript database

Carbohydrate import into seeds directly determines seed size and must have been increased through domestication. However, evidence for domestication of sugar translocation and the identity of seed filling transporters remained elusive. Maize ZmSWEET4c, as opposed to its sucrose-transporting homologs...

[Influence of paddy rice-upland crop rotation of cold-waterlogged paddy field on crops produc- tion and soil characteristics].

PubMed

Wang, Fei; Li, Qing-hua; Lin, Cheng; He, Chun-mei; Zhong, Shao-jie; Li, Yu; Lin, Xin-jian; Huang, Jian-cheng

2015-05-01

Two consecutive years (4-crop) experiments were conducted to study the influence of different paddy rice-upland crop rotation in cold-waterlogged paddy field on the growth of crops and soil characteristics. The result showed that compared with the rice-winter fallow (CK) pattern, the two-year average yield of paddy rice under four rotation modes, including rape-rice (R-R), spring corn-rice (C-R), Chinese milk vetch-rice (M-R) and bean-rice (B-R), were increased by 5.3%-26.7%, with significant difference observed in C-R and R-R patterns. Except for M-R pattern, the annual average total economic benefits were improved by 79.0%-392.4% in all rotation pattern compared with the CK, and the ration of output/input was enhanced by 0.06-0.72 unit, with the most significant effect found in the C-R pattern. Likewise, compared with the CK, the contents of chlorophyll and carotenoid, and net photosynthetic rate (Pn) of rice plant were all increased during the full-tillering stage of rice in all rotation patterns. The rusty lines and rusty spots of soils were more obvious compared with the CK during the rice harvest, particularly in R-R, C-R and B-R patterns. The ratio of water-stable soil macro aggregates of plough layer of soil (> 2 mm) decreased at different levels in all rotation patterns while the ratios of middle aggregate (0.25-2 mm, expect for M-R) and micro aggregate of soil (< 0.25 mm) were opposite. There was a decreasing trend for soil active reducing agents in all rotation patterns, whereas the available nutrient increased. The amounts of soil bacteria in C-R and B-R patterns, fungi in B-R rotation pattern, cellulose bacteria in R-R, C-R and B-R patterns and N-fixing bacteria in B-R pattern were improved by 285.7%-403.0%, 221.7%, 64.6-92.2% and 162.2%, respectively. Moreover, the differences in all microorganisms were significant. Thus, based on the experimental results of cold-waterlogged paddy field, it was concluded that changing from single cropping rice system to C-R, R-R and B-R rotation patterns had good effect in terms of improving total yield and economic benefits, and soil physical and chemical properties were improved.

Risk assessment and vertical distribution of thallium in paddy soils and uptake in rice plants irrigated with acid mine drainage.

PubMed

Huang, Xuexia; Li, Ning; Wu, Qihang; Long, Jianyou; Luo, Dinggui; Zhang, Ping; Yao, Yan; Huang, Xiaowu; Li, Dongmei; Lu, Yayin; Liang, Jianfeng

2016-12-01

The objective of this paper is to assess the influence of irritating paddy fields with acid mine drainage containing thallium (Tl) to rice plant-soil system and potential health risks for local residents. Vertical distribution of Tl, pH, organic matter (OM), and cation exchange capacity (CEC) in 24 paddy soil profiles around Yunfu pyrite mine area was investigated. Rice plant samples were collected from the corresponding soil sampling site. The results showed that Tl concentrations in paddy soils at 0-60 cm depth range from 3.07 to 9.42 mg kg -1 , with a mean of 5.74 mg kg -1 , which were significantly higher than the background value of soil in China (0.58 mg kg -1 ). On the whole, Tl contents in paddy soil profiles increased quickly with soil depth from 0 to 30 cm and decreased slowly with soil depth from 30 to 60 cm. The soil Tl content was significant negatively correlated with soil pH. The mean content of Tl in the root, stem, leaf, and rice was 4.36, 1.83, 2.74, and 1.42 mg kg -1 , respectively, which exceeded the proposed permissible limits for foods and feedstuffs in Germany. The Tl content in various tissues of the rice plants followed the order root > leaf > stem (rice), which suggested that most Tl taken up by rice plants retained in the root, and a little migrated to the leaf, stem, and rice. Correlation analysis showed that Tl content in root was significant positively correlated with Tl content in leaf and rice. The ranges of hazard quotient (HQ) values were 4.08∼24.50 and 3.84∼22.38 for males and females, respectively. Males have higher health risk than females in the same age group. In childhood age groups (2 to <21 years) and adult age groups (21 to <70 years), the highest health risk level was observed in the 11 to 16 age group and 21 to 50 age group, respectively. The findings indicated that regular irrigation with Tl-bearing acid mine drainage led to considerable contamination of Tl in paddy soil and rice plant. Local government should take various measures to treat Tl contamination, especially the tailings.

Transplant production

USDA-ARS?s Scientific Manuscript database

For field pepper (Capsicum spp.) production, plants can be established from direct seed or transplants depending on the location and cultural practices for the specific pepper type grown. Direct seeding can result in slow, variable, and reduced plant stands due to variations in soil temperature, wat...

Making equipment to process paddy water for providing drinking water by using Ozone-UVC& Ultrafiltration

NASA Astrophysics Data System (ADS)

Styani, E.; Dja'var, N.; Irawan, C.; Hanafi

2018-01-01

This study focuses on making equipment which is useful to process paddy water to be consumable as drinking water by using ozone-UVC and ultrafiltration. The equipment which is made by the process of ozone-UVC and ultrafiltration or reverse osmosis is driven by electric power generated from solar panels. In the experiment, reverse osmosis system with ozone-UVC reactor proves to be good enough in producing high quality drinking water.

Phyllosphere bacterial community of floating macrophytes in paddy soil environments as revealed by illumina high-throughput sequencing.

PubMed

Xie, Wan-Ying; Su, Jian-Qiang; Zhu, Yong-Guan

2015-01-01

The phyllosphere of floating macrophytes in paddy soil ecosystems, a unique habitat, may support large microbial communities but remains largely unknown. We took Wolffia australiana as a representative floating plant and investigated its phyllosphere bacterial community and the underlying driving forces of community modulation in paddy soil ecosystems using Illumina HiSeq 2000 platform-based 16S rRNA gene sequence analysis. The results showed that the phyllosphere of W. australiana harbored considerably rich communities of bacteria, with Proteobacteria and Bacteroidetes as the predominant phyla. The core microbiome in the phyllosphere contained genera such as Acidovorax, Asticcacaulis, Methylibium, and Methylophilus. Complexity of the phyllosphere bacterial communities in terms of class number and α-diversity was reduced compared to those in corresponding water and soil. Furthermore, the bacterial communities exhibited structures significantly different from those in water and soil. These findings and the following redundancy analysis (RDA) suggest that species sorting played an important role in the recruitment of bacterial species in the phyllosphere. The compositional structures of the phyllosphere bacterial communities were modulated predominantly by water physicochemical properties, while the initial soil bacterial communities had limited impact. Taken together, the findings from this study reveal the diversity and uniqueness of the phyllosphere bacterial communities associated with the floating macrophytes in paddy soil environments. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The carbon count of 2000 years of rice cultivation.

PubMed

Kalbitz, Karsten; Kaiser, Klaus; Fiedler, Sabine; Kölbl, Angelika; Amelung, Wulf; Bräuer, Tino; Cao, Zhihong; Don, Axel; Grootes, Piet; Jahn, Reinhold; Schwark, Lorenz; Vogelsang, Vanessa; Wissing, Livia; Kögel-Knabner, Ingrid

2013-04-01

More than 50% of the world's population feeds on rice. Soils used for rice production are mostly managed under submerged conditions (paddy soils). This management, which favors carbon sequestration, potentially decouples surface from subsurface carbon cycling. The objective of this study was to elucidate the long-term rates of carbon accrual in surface and subsurface soil horizons relative to those of soils under nonpaddy management. We assessed changes in total soil organic as well as of inorganic carbon stocks along a 2000-year chronosequence of soils under paddy and adjacent nonpaddy management in the Yangtze delta, China. The initial organic carbon accumulation phase lasts much longer and is more intensive than previously assumed, e.g., by the Intergovernmental Panel on Climate Change (IPCC). Paddy topsoils accumulated 170-178 kg organic carbon ha(-1) a(-1) in the first 300 years; subsoils lost 29-84 kg organic carbon ha(-1) a(-1) during this period of time. Subsoil carbon losses were largest during the first 50 years after land embankment and again large beyond 700 years of cultivation, due to inorganic carbonate weathering and the lack of organic carbon replenishment. Carbon losses in subsoils may therefore offset soil carbon gains or losses in the surface soils. We strongly recommend including subsoils into global carbon accounting schemes, particularly for paddy fields. © 2012 Blackwell Publishing Ltd.

Phyllosphere Bacterial Community of Floating Macrophytes in Paddy Soil Environments as Revealed by Illumina High-Throughput Sequencing

PubMed Central

Xie, Wan-Ying

2014-01-01

The phyllosphere of floating macrophytes in paddy soil ecosystems, a unique habitat, may support large microbial communities but remains largely unknown. We took Wolffia australiana as a representative floating plant and investigated its phyllosphere bacterial community and the underlying driving forces of community modulation in paddy soil ecosystems using Illumina HiSeq 2000 platform-based 16S rRNA gene sequence analysis. The results showed that the phyllosphere of W. australiana harbored considerably rich communities of bacteria, with Proteobacteria and Bacteroidetes as the predominant phyla. The core microbiome in the phyllosphere contained genera such as Acidovorax, Asticcacaulis, Methylibium, and Methylophilus. Complexity of the phyllosphere bacterial communities in terms of class number and α-diversity was reduced compared to those in corresponding water and soil. Furthermore, the bacterial communities exhibited structures significantly different from those in water and soil. These findings and the following redundancy analysis (RDA) suggest that species sorting played an important role in the recruitment of bacterial species in the phyllosphere. The compositional structures of the phyllosphere bacterial communities were modulated predominantly by water physicochemical properties, while the initial soil bacterial communities had limited impact. Taken together, the findings from this study reveal the diversity and uniqueness of the phyllosphere bacterial communities associated with the floating macrophytes in paddy soil environments. PMID:25362067

Analysis of the interaction among rice, weeds, inorganic fertilizer, and a herbivore in a composite farming paddy ecosystem.

PubMed

Wu, Zhaohua; Wang, Yi; Zhou, Xiaoli; Zhou, Tiejun

2018-06-01

As one of the Globally Important Agricultural Heritage Systems (GIAHS), rice field composite farming is an ecological measure in rice production, which can reduce the amount of chemical fertilizers, pesticides and herbicides. This research studies the interaction among rice, weed, inorganic fertilizer and herbivore in a composite farming paddy ecosystem. We develop a differential equation model to analyze the relations and interactions among those components. Results show the existence of an equilibrium for paddy and weed extinction, one or two equilibria for rice extinction, an equilibrium for weed extinction, and an equilibrium for rice and weed coexistence. Based on the obtained stability conditions of these equilibria, measures are proposed to avoid the existence or the stability of equilibria for rice extinction. Other measures are proposed to lead to a stable equilibrium for weed extinction, which is the most desirable result in rice production. Conditions for maximizing the yield of rice are also obtained by taking the relative mortality of rice as variable. In addition, we discover the existence of Hopf bifurcation phenomenon in the system, and develop the critical value of Hopf bifurcation by taking the artificial fertilizer rate as the bifurcation parameter. Our findings provide effective guidance and insights for rice production in a composite farming paddy ecosystem. Copyright © 2018 Elsevier Inc. All rights reserved.

Optimizing rice plant photosynthate allocation reduces N2O emissions from paddy fields

NASA Astrophysics Data System (ADS)

Jiang, Yu; Huang, Xiaomin; Zhang, Xin; Zhang, Xingyue; Zhang, Yi; Zheng, Chengyan; Deng, Aixing; Zhang, Jun; Wu, Lianhai; Hu, Shuijin; Zhang, Weijian

2016-07-01

Rice paddies are a major source of anthropogenic nitrous oxide (N2O) emissions, especially under alternate wetting-drying irrigation and high N input. Increasing photosynthate allocation to the grain in rice (Oryza sativa L.) has been identified as an effective strategy of genetic and agronomic innovation for yield enhancement; however, its impacts on N2O emissions are still unknown. We conducted three independent but complementary experiments (variety, mutant study, and spikelet clipping) to examine the impacts of rice plant photosynthate allocation on paddy N2O emissions. The three experiments showed that N2O fluxes were significantly and negatively correlated with the ratio of grain yield to total aboveground biomass, known as the harvest index (HI) in agronomy (P < 0.01). Biomass accumulation and N uptake after anthesis were significantly and positively correlated with HI (P < 0.05). Reducing photosynthate allocation to the grain by spikelet clipping significantly increased white root biomass and soil dissolved organic C and reduced plant N uptake, resulting in high soil denitrification potential (P < 0.05). Our findings demonstrate that optimizing photosynthate allocation to the grain can reduce paddy N2O emissions through decreasing belowground C input and increasing plant N uptake, suggesting the potential for genetic and agronomic efforts to produce more rice with less N2O emissions.

The Dynamics of Energy and CO2 Transport above a Subtropical Rice Paddy

NASA Astrophysics Data System (ADS)

Hsieh, C.; Huang, C.; Cheng, S.

2013-12-01

An eddy-covariance system was established to understand the dynamics of turbulent transport of sensible heat, water vapor, and CO2 above a subtropical rice paddy in north Taiwan (24°48'07.958'N, 121°47'58.665'E). The results showed that, during crop season, about 25% of net radiation was used for latent heat flux, 10% for sensible heat flux, and the rest (65%) was absorbed by the water and soil in the rice paddy. However, during fallow period, where there was no rice in the paddy, both water vapor and sensible heat fluxes occupied about 18% of the net radiation. Also, Penman-Monteith equation was found to reproduce the water vapor flux well with surface resistance close to 190 s m-1. We also found that, under small Bowen ratio (< 0.2) conditions, water vapor and CO2 were transported more efficiently than heat. However, when Bowen ration was large (> 0.5), sensible heat was transported about 10% more efficiently than both water vapor and CO2. During crop season the maximum CO2 uptake was about 22 micro mol m-2 s-1. In fallow period, the maximum CO2 emission rate from the soil-water surface was around 5 micro mol m-2 s-1, which was about the same as the growing season.

Alterations of biochemical indicators in hepatopancreas of the golden apple snail, Pomacea canaliculata, from paddy fields in Taiwan.

PubMed

Chiu, Yuh-Wen; Wu, Jui-Pin; Hsieh, Tsung-Chih; Liang, Shih-Hsiung; Chen, Chien-Min; Huang, Da-Ji

2014-07-01

The freshwater golden apple snail, Pomacea canaliculata, is one of the world's 100 worst invasive alien species. The snails' wide distribution, high abundance, and sensitivity to environmental pollution make them a potential bioindicator for environmental contamination. In this study, the biochemical status of golden apple snails collected from paddy fields throughout the island of Taiwan was examined. This study found that the biochemical status of apple snails collected from paddy fields differed from that of animals bred and maintained in the laboratory. Furthermore, certain biochemical endpoints of the snails collected from the paddy fields before and after agricultural activities were also different-hemolymphatic vitellogenin protein was induced in male snail after exposure to estrogen-like chemicals, the hepatic monooxygenase (1.97 +/- 0.50 deltaA(650mm) 30 min(-1) mg(-1) protein in control group) and glutathione S transferase (0.02 +/- 0.01 delta A(340mm) 30 min(-1) mg(-1) protein in control group) snails exposed to pesticides, as well as the hepatopancreatic levels of aspartate aminotransferase (450.00 +/- 59.40 U mg(-1) mg(-1) protein in control group) and alanine aminotransferase (233.27 +/- 42.09 U mg(-1) mg(-1) protein in control group) decreased the indicating that xenobiotics destroyed hepatopancreatic. The above findings reveal that apple snail could be used as a practical bioindicator to monitor anthropogenic environmental pollution.

Bacterial, archaeal, and fungal community responses to acid mine drainage-laden pollution in a rice paddy soil ecosystem.

PubMed

Wang, Han; Zeng, Yufei; Guo, Chuling; Bao, Yanping; Lu, Guining; Reinfelder, John R; Dang, Zhi

2018-03-01

Lacking sufficient clean water, the paddy soils along the Hengshi River have suffered from long-term acid mine drainage (AMD) contamination. The impacted cropland is too heavily contaminated to grow food safely. The microbial communities inhabiting the environment play pivotal roles in the crop growth, health, and ecological services. In this study, the bacterial, archaeal, and fungal communities in the impacted paddy soil were examined using high-throughput Illumina MiSeq sequencing. The results showed that AMD irrigation considerably enriched the bacterial phylum Acidobacteria and the archaeal phylum Crenarchaeota, while the fungal community was more stable. The abundances of Acidobacteria and Crenarchaeota were significantly positively correlated with the AMD-related environmental factors of pH and heavy metals (Cu, Pb, and Zn). In the most contaminated samples, communities were dominated by the bacteria Candidatus Solibacter and Candidatus Koribacter from the Acidobacteria family. Functional gene profile analysis demonstrated that the energy metabolic processes of the microbial communities, especially C/N related pathways, have adjusted and are well-adapted to tolerating AMD contamination. The present study described the structural and functional differentiation of microbial communities in the rice paddy soil under AMD irrigation. The results are useful for the development of bioremediation strategies using native microbes in the cleanup and biorestoration of AMD-contaminated agriculture soil. Copyright © 2017 Elsevier B.V. All rights reserved.

Using 13C isotopes to explore denitrification-dependent anaerobic methane oxidation in a paddy-peatland.

PubMed

Shi, Yao; Wang, Zhongqiang; He, Chunguang; Zhang, Xinyu; Sheng, Lianxi; Ren, Xiaodong

2017-01-18

Peatlands are organic-matter-rich but nitrogen-limited natural systems, the carbon/nitrogen (C/N) status of which are subject to increasing exposure from long-term nitrate (NO 3 - ) fertilizer inputs and atmospheric nitrogen (N) deposits. To manage and protect these unique environments, an improved understanding of denitrification-dependent anaerobic oxidation of methane (DAMO) in peatlands is needed. In this study, we used stable isotope measurements and incubation with NO 3 - additions to facilitate an investigation and comparison of the potential DAMO rates in a paddy-peatland that has been influenced by N fertilizer over 40 years and an undisturbed peatland in northeast China. Monitoring of 13 CO 2 production confimed DAMO did occur in both the paddy-peatland and the undisturbed peatland, the rates of which increased with NO 3 - additions, but decreased logarithmically with time. When NO 3 - was added, there were no significant differences between the CH 4 oxidation in the paddy-peatland and peatland samples after 36 hours of incubation (97.08 vs. 143.69 nmol g -1 dry peat) and the potential DAMO rate after incubation for 1 hour (92.53 vs. 69.99 nmol g -1  h -1 ). These results indicate that the occurrence of DAMO in peatlands might be controlled by the amount of NO 3 - applied and the depth to which it penetrates into the anoxic layer.

Reducing nitrogen runoff from paddy fields with arbuscular mycorrhizal fungi under different fertilizer regimes.

PubMed

Zhang, Shujuan; Wang, Li; Ma, Fang; Zhang, Xue; Fu, Dafang

2016-08-01

Nitrogen (N) runoff from paddy fields serves as one of the main sources of water pollution. Our aim was to reduce N runoff from paddy fields by fertilizer management and inoculation with arbuscular mycorrhizal fungi (AMF). In northeast China, Shuangcheng city in Heilongjiang province, a field experiment was conducted, using rice provided with 0%, 20%, 40%, 60%, 80%, and 100% of the local norm of fertilization (including N, phosphorus and potassium), with or without inoculation with Glomus mosseae. The volume, concentrations of total N (TN), dissolved N (DN) and particulate N (PN) of runoff water were measured. We found that the local norm of fertilization led to 18.9kg/ha of N runoff during rice growing season, with DN accounting for 60%-70%. We also found that reduction in fertilization by 20% cut down TN runoff by 8.2% while AMF inoculation decreased N runoff at each fertilizer level and this effect was inhibited by high fertilization. The combination of inoculation with AMF and 80% of the local norm of fertilization was observed to reduce N runoff by 27.2%. Conclusively, we suggested that the contribution of AMF inoculation combined with decreasing fertilization should get more attention to slow down water eutrophication by reducing N runoff from paddy fields. Copyright © 2016. Published by Elsevier B.V.

Coupling AVHRR imagery with biogeochemical models of methane emission from rice crops

NASA Astrophysics Data System (ADS)

Paliouras, Eleni Joyce

2000-10-01

Rice is a staple food source for much of the world and most of it is grown in paddies which remain flooded for a large part of the growing season. This anaerobic environment is ideal for the activities of methanogenic bacteria, that are responsible for the production of methane gas, some of which is released into the atmosphere. In order to better understand the role that rice cropping plays in the levels of atmospheric methane, several models have been developed to predict the methane flux from the paddies. These models generally utilize some type of nominal plant growth curve based on one or two pieces of ground truth data. Ideally, satellite data could be used instead to provide these models with an estimate of biomass change over the growing season, eliminating the need for related ground truth. A technique proposed to accomplish this is presented here, and results that demonstrate its success when applied to rice cropping areas of Texas are discussed. Also presented is a method for utilizing satellite data to map rice cropping areas that could eventually aid in a scheme for populating a GIS-type database with information on exact rice cropping areas. Such a database could then be directly tied to the methane emission models to obtain flux estimates for extensive regional areas.

Cryopreservation of lipid-rich seeds: effect of moisture content and cooling rate on germination.

PubMed

González-Benito, E M; Pérez-García, F

2001-01-01

The effect of fast and slow cooling on germination of seeds from two Brassicaceae species (Eruca vesicaria (L.) Cav., Brassica napus L. var. oleifera (Moench) DC cv. Bingo) and cypselas from three Compositae species (Onopordum nervosum Boiss., Onopordum acanthium L., Helianthus annuus L. cv. Viky) at different moisture contents was studied. Seed lipid content (dry weight basis) ranged from 15% (O. nervosum) to 41% (H. annuus). For each species, seeds with four moisture contents were cryopreserved either by direct immersion in liquid nitrogen or by previous cooling at 10 degrees C/min from room temperature to -50 degrees C. In three species (E. vesicaria, B. napus, and H. annuus) germination of air-dried (6.2-8.9% moisture content) seeds cooled by direct immersion in liquid nitrogen was not significantly different from germination of control seeds (air-dried, non-cooled). In the two Onorpordum species the best response among cooling treatments was observed when air-dried seeds were slowly cooled.

extendFromReads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Kelly P.

2013-10-03

This package assists in genome assembly. extendFromReads takes as input a set of Illumina (eg, MiSeq) DNA sequencing reads, a query seed sequence and a direction to extend the seed. The algorithm collects all seed-- ]matching reads (flipping reverse-- ]orientation hits), trims off the seed and additional sequence in the other direction, sorts the remaining sequences alphabetically, and prints them aligned without gaps from the point of seed trimming. This produces a visual display distinguishing the flanks of multi- ]copy seeds. A companion script hitMates.pl collects the mates of seed-- ]hi]ng reads, whose alignment reveals longer extensions from the seed.more » The collect/trim/sort strategy was made iterative and scaled up in the script denovo.pl, for de novo contig assembly. An index is pre-- ]built using indexReads.pl that for each unique 21-- ]mer found in all the reads, records its gfate h of extension (whether extendable, blocked by low coverage, or blocked by branching after a duplicated sequence) and other characteristics. Importantly, denovo.pl records all branchings that follow a branching contig endpoint, providing contig- ]extension information« less

An Approach to Assessing Flood Risk in Low-lying Paddy Areas of Japan considering Economic Damage on Rice

NASA Astrophysics Data System (ADS)

Minakawa, H.; Masumoto, T.

2013-12-01

Hiroki Minakawa, Takao Masumoto National Institute for Rural Engineering (NIRE), NARO, Japan Flooding is one type of nature disaster, and is caused by heavy rainfall events. In the future, the risk of flooding is predicted to increase due to global climate change. Immediate measures such as strengthening drainage capacity are needed to minimize the damage caused by more frequent flooding, so a quantitative evaluation method of flood risks is needed to discuss countermeasure against these problems. At the same time, rice is an important crop for food production in Japan. However, paddy fields are often damaged by flooding because they are principally spread in lower part of the basin. Therefore, it is also important to assess the damages to paddy fields. This study discusses a method for evaluating a relationship between the risk of flood damage and the scale of heavy rainfall. We also developed a method of estimating the economic effect of a reduction in rice yield by flooding. First, we developed a drainage analysis model that incorporates kinematic and diffusive runoff models for calculating water level in channels and paddies. Next, heavy rainfall data for drainage analyses were generated by using a diurnal rainfall pattern generator. The generator can create hourly data of heavy rainfall, and internal pattern of them is different each. These data were input to the drainage model to estimate flood risk. Simultaneously, we tried to clarify economic losses of a rice yields caused by flooding. Here, the reduction scale in rice yield which shows relations between flooding situation (e.g. water level, duration of submersion etc.) and damage of rice is available to calculate reduction of rice yield. In this study, we created new reduction scales through a pseudo-flooding experiment under real inundation conditions. The methodology of the experiment was as follow: We chose the popular Japanese rice cultivar Koshihikari for this experiment. An experimental arena was constructed in a rice paddy plot, which consisted of two zones, one in which the rice was cultivated as usual with normal water levels, and a flood zone, which was used for submerging rice plants. The flood zone, which was designed to reproduce actual flood disaster conditions in paddy fields, can be filled with water to a depth of 0.3, 0.6 or 0.9 m above ground level, and is divided into two plots, a clean water part and a turbid water part. Thus, the experimental conditions can vary according to 1) the development stage of rice, 2) complete or incomplete submersion, 3) clean or turbid water, and 4) duration of submergence. Finally, the reduction scales were formulated by using the resultant data and it was found that rice is most sensitive to damage during the development stage. Flood risk was evaluated by using calculated water level on each paddy. Here, the averaged duration of inundation to a depth of more than 0.3 m was used as the criteria for flood occurrence. The results indicated that the duration increased with larger heavy rainfall amounts. Furthermore, the damage to rice was predicted to increase especially in low-lying paddy fields. Mitigation measures, such as revising drainage planning and/or changing design standards for the capacity of drainage pumps may be necessary in the future.

Nutrients levels in paddy soils and flood waters from Tagus-Sado basin: the impact of farming system

NASA Astrophysics Data System (ADS)

Santos, Erika S.; Abreu, Maria Manuela; Magalhães, Maria Clara; Viegas, Wanda; Amâncio, Sara; Cordovil, Cláudia

2017-04-01

Application of fertilizers for crops can contribute to nutrients surplus, namely nitrogen, in both groundwater and surface waters resulting in serious environmental problems. The impacts on water quality due to fertilizers are related to land management. In paddy fields using high amounts of water, the nutrient dynamic knowledge is essential to evaluate the impact of farming system. The aims of this study were to evaluate: i)nutrients levels in soils and floodwaters from rice cultivation in Tagus-Sado basin (Portugal); ii)the effect, under controlled conditions, of different irrigation techniques on nutrient enrichment of floodwaters from rice cultivation. Composite samples (n=24) of paddy soils (0-15 cm) and floodwaters were collected, during rice flooding period. In the field, pH and electrical conductivity (EC) were determined in waters. Soil pH, concentrations of Corganic, NPK and nutrients (Ca, Cu, Fe, Mg, Mn, Zn) in soils and floodwaters (nitrites, nitrates, phosphates) were determined. A mesocosm assay was performed in lysimeters with a paddy soil (pH: 5.6; g/kg- Ntotal: 2.0, Pextractable: 0.04, Kextractable: 0.6, Corganic: 35.5) and different irrigation techniques (n=3): a)flood; b)four floods per day (great water renewal); c)flood until rice flowering and then a normal superficial irrigation. Rice cultivation was done by transplant as in the field. Irrigation water come from a well. Same chemical characterization than in field assay were determined in floodwater and irrigation water. In field conditions, paddy soils had values of pH between 5.1 and 8.1 and a great fertility range (g/kg; Ntotal: 0.4‒2.2; Pextractable: 0.01‒0.2; Kextractable: 0.04‒0.7; Corganic: 6.5‒37.9). Total soil concentrations of Cu, Fe, and Zn in soils were in same range and below maximum admissible values for agriculture. Total soil concentrations of Ca, Mg and Mn, showed higher heterogeneity (g/kg; 1.2‒19.3, 7.6‒34.2 and 0.2‒1.5 respectively). Floodwaters presented pH ≈7 and, usually, EC>1 mS/cm (MRV‒maximum recommended value for irrigation water). Nitrites concentrations were <0.1 mg/L in floodwaters, while concentrations of nitrates (<2.4 mg/L), Cu (<2‒12.3 µg/L), Fe (<0.1‒0.9 mg/L) and Zn (0.04‒1.9 mg/L) were below MRV. The fertilizers used in rice cultivation did not seem to affect the water quality. Nitrates concentration in irrigation water of lysimeters (24 mg/L) was close to MVR for irrigation water. Intensive agriculture of corn surrounding the well can explain the greater nutrients concentrations, especially nitrates, nitrites and phosphates, in this water compared to water from river used for paddy fields irrigation. Independently of irrigation technique, nutrient concentrations in lysimeters floodwaters (except phosphates in some samples) were in same range of those in irrigation water from well. The nutrients excess in water seems not to be uptake by rice contributing to nutrient enrichment of nearby waters and soils. Studied paddy fields from Tejo-Sado basin are not a potential pollution source of nutrients. However, according mesocosm assay, the potential irrigation of paddy soils with water rich in nitrates can contribute to serious environmental risks. The authors are thankful to: Atlantic Meals for financial and sampling support, and NitroPortugal, H2020-TWINN-2015, EU coordination and support action n. 692331 funding.

Identification and isolation of active N2O reducers in rice paddy soil

PubMed Central

Ishii, Satoshi; Ohno, Hiroki; Tsuboi, Masahiro; Otsuka, Shigeto; Senoo, Keishi

2011-01-01

Dissolved N2O is occasionally detected in surface and ground water in rice paddy fields, whereas little or no N2O is emitted to the atmosphere above these fields. This indicates the occurrence of N2O reduction in rice paddy fields; however, identity of the N2O reducers is largely unknown. In this study, we employed both culture-dependent and culture-independent approaches to identify N2O reducers in rice paddy soil. In a soil microcosm, N2O and succinate were added as the electron acceptor and donor, respectively, for N2O reduction. For the stable isotope probing (SIP) experiment, 13C-labeled succinate was used to identify succinate-assimilating microbes under N2O-reducing conditions. DNA was extracted 24 h after incubation, and heavy and light DNA fractions were separated by density gradient ultracentrifugation. Denaturing gradient gel electrophoresis and clone library analysis targeting the 16S rRNA and the N2O reductase gene were performed. For culture-dependent analysis, the microbes that elongated under N2O-reducing conditions in the presence of cell-division inhibitors were individually captured by a micromanipulator and transferred to a low-nutrient medium. The N2O-reducing ability of these strains was examined by gas chromatography/mass spectrometry. Results of the SIP analysis suggested that Burkholderiales and Rhodospirillales bacteria dominated the population under N2O-reducing conditions, in contrast to the control sample (soil incubated with only 13C-succinate). Results of the single-cell isolation technique also indicated that the majority of the N2O-reducing strains belonged to the genera Herbaspirillum (Burkholderiales) and Azospirillum (Rhodospirillales). In addition, Herbaspirillum strains reduced N2O faster than Azospirillum strains. These results suggest that Herbaspirillum spp. may have an important role in N2O reduction in rice paddy soils. PMID:21677691

Mitigating yield-scaled greenhouse gas emissions through combined application of soil amendments: A comparative study between temperate and subtropical rice paddy soils.

PubMed

Ali, Muhammad Aslam; Kim, P J; Inubushi, K

2015-10-01

Effects of different soil amendments were investigated on methane (CH4) and nitrous oxide (N2O) emissions, global warming potential (GWP) and yield scaled GWPs in paddy soils of Republic of Korea, Japan and Bangladesh. The experimental treatments were NPK only, NPK+fly ash, NPK+silicate slag, NPK+phosphogypsum(PG), NPK+blast furnace slag (BFS), NPK+revolving furnace slag (RFS), NPK+silicate slag (50%)+RFS (50%), NPK+biochar, NPK+biochar+Azolla-cyanobacteria, NPK+silicate slag+Azolla-cyanobacteria, NPK+phosphogypsum (PG)+Azolla-cyanobacteria. The maximum decrease in cumulative seasonal CH4 emissions was recorded 29.7% and 32.6% with Azolla-cyanobacteria plus phospho-gypsum amendments in paddy soils of Japan and Bangladesh respectively, followed by 22.4% and 26.8% reduction with silicate slag plus Azolla-cyanobacteria application. Biochar amendments in paddy soils of Japan and Bangladesh decreased seasonal cumulative N2O emissions by 31.8% and 20.0% respectively, followed by 26.3% and 25.0% reduction with biochar plus Azolla-cyanobacteria amendments. Although seasonal cumulative CH4 emissions were significantly increased by 9.5-14.0% with biochar amendments, however, global warming potentials were decreased by 8.0-12.0% with cyanobacterial inoculation plus biochar amendments. The maximum decrease in GWP was calculated 22.0-30.0% with Azolla-cyanobacteria plus silicate slag amendments. The evolution of greenhouse gases per unit grain yield (yield scaled GWP) was highest in the NPK treatment, which was decreased by 43-50% from the silicate slag and phosphogypsum amendments along with Azolla-cyanobacteria inoculated rice planted soils. Conclusively, it is recommended to incorporate Azolla-cyanobacteria with inorganic and organic amendments for reducing GWP and yield scaled GWP from the rice planted paddy soils of temperate and subtropical countries. Copyright © 2015 Elsevier B.V. All rights reserved.

Environmental and economic risks assessment under climate changes for three land uses scenarios analysis across Teshio watershed, northernmost of Japan.

PubMed

Fan, Min; Shibata, Hideaki; Chen, Li

2017-12-01

Land use and climate changes affect on the economy and environment with different patterns and magnitudes in the watershed. This study used risk analysis model stochastic efficiency with respect to a function (SERF) to evaluate economic and environmental risks caused by four climate change scenarios (baseline, small-, mid- and large changes) and three land uses (paddy dominated, paddy-farmland mixture and farmland dominated for agriculture) in Teshio watershed in northern Hokkaido, Japan. Under the baseline climate conditions, the lower ranking of economic income of crop yield and higher ranking of pollutant load from agricultural land were both predicted in paddy dominated for agriculture, suggesting that the paddy dominated system caused higher risks of economic and environmental variables compared to other two land uses. Increase of temperature and precipitation increased crop yields under all three climate changes which resulted in increase of the ranking of economic income, indicating that those climate changes could reduce economic risk. The increased temperature and precipitation also accelerated mineralization of organic nutrient and nutrient leaching to river course of Teshio which resulted in increase of the ranking of pollutant load, suggesting that those climate changes could lead to more environmental risk. The rankings of economic income in mid- and large changes of climate were lower than that in small change of climate under paddy-farmland mixture and farmland dominated systems due to decrease of crop yield, suggesting that climate change led to more economic risk. In summary, the results suggested that increase in temperature and precipitation caused higher risks of both economic and environmental perspectives, and the impacts was higher than those of land use changes in the studied watershed. Those findings would help producers and watershed managers to measure the tradeoffs between environmental protection and agricultural economic development for making decision under land use and climate changes. Copyright © 2017 Elsevier B.V. All rights reserved.

Conversion from rice to vegetable production increases N2O emission via increased soil organic matter mineralization.

PubMed

Wu, Lei; Tang, Shuirong; He, Dongdong; Wu, Xian; Shaaban, Muhammad; Wang, Milan; Zhao, Jingsong; Khan, Imran; Zheng, Xunhua; Hu, Ronggui; Horwath, William R

2017-04-01

The conversion from rice to vegetable production widely occurs in China. However, the effects of this conversion on N 2 O emission and the underlying mechanisms are not well understood. In the present study, 12 rice paddies (R) were selected and half of them converted to vegetable fields (V) with the following treatments: rice paddies without N-fertilizer (R-CK), rice paddies with conventional N-fertilizer (R-CN), converted vegetable fields without N-fertilizer (V-CK), and converted vegetable fields with conventional N-fertilizer (V-CN) in a randomized block design with 3 replicates. N 2 O emissions were measured with static chambers from December 2012 to December 2015. Within each V-CN plot, a root exclusion subplot was established to measure soil heterotrophic respiration (CO 2 effluxes), a proxy for soil organic matter mineralization. Conversion of rice paddies to vegetable production dramatically increased N 2 O emissions. The three-year cumulative N 2 O emissions were 0.59, 1.90, 55.50 and 160.14kg N ha -1 for R-CK, R-CN, V-CK and V-CN, respectively. The annual N 2 O emissions from vegetable fields ranged between 5.99 and 113.45kg N ha -1 yr -1 , with substantially higher emissions in the first year. N 2 O fluxes from V-CN were significantly and positively related to CO 2 fluxes and inorganic N concentrations. The linear relationship between natural logarithms of N 2 O and CO 2 fluxes was stronger and the regression coefficient higher in the first year, showing the dependence of N 2 O on soil organic matter mineralization. These results suggest that soil organic matter and N mineralization contributes significantly to N 2 O emission following conversion of rice paddies to vegetable production. Copyright © 2017 Elsevier B.V. All rights reserved.

Integration of artificial intelligence methods and life cycle assessment to predict energy output and environmental impacts of paddy production.

PubMed

Nabavi-Pelesaraei, Ashkan; Rafiee, Shahin; Mohtasebi, Seyed Saeid; Hosseinzadeh-Bandbafha, Homa; Chau, Kwok-Wing

2018-08-01

Prediction of agricultural energy output and environmental impacts play important role in energy management and conservation of environment as it can help us to evaluate agricultural energy efficiency, conduct crops production system commissioning, and detect and diagnose faults of crop production system. Agricultural energy output and environmental impacts can be readily predicted by artificial intelligence (AI), owing to the ease of use and adaptability to seek optimal solutions in a rapid manner as well as the use of historical data to predict future agricultural energy use pattern under constraints. This paper conducts energy output and environmental impact prediction of paddy production in Guilan province, Iran based on two AI methods, artificial neural networks (ANNs), and adaptive neuro fuzzy inference system (ANFIS). The amounts of energy input and output are 51,585.61MJkg -1 and 66,112.94MJkg -1 , respectively, in paddy production. Life Cycle Assessment (LCA) is used to evaluate environmental impacts of paddy production. Results show that, in paddy production, in-farm emission is a hotspot in global warming, acidification and eutrophication impact categories. ANN model with 12-6-8-1 structure is selected as the best one for predicting energy output. The correlation coefficient (R) varies from 0.524 to 0.999 in training for energy input and environmental impacts in ANN models. ANFIS model is developed based on a hybrid learning algorithm, with R for predicting output energy being 0.860 and, for environmental impacts, varying from 0.944 to 0.997. Results indicate that the multi-level ANFIS is a useful tool to managers for large-scale planning in forecasting energy output and environmental indices of agricultural production systems owing to its higher speed of computation processes compared to ANN model, despite ANN's higher accuracy. Copyright © 2018 Elsevier B.V. All rights reserved.

Efficacy of Aquatain, a Monomolecular Film, for the Control of Malaria Vectors in Rice Paddies

PubMed Central

Bukhari, Tullu; Takken, Willem; Githeko, Andrew K.; Koenraadt, Constantianus J. M.

2011-01-01

Background Rice paddies harbour a large variety of organisms including larvae of malaria mosquitoes. These paddies are challenging for mosquito control because their large size, slurry and vegetation make it difficult to effectively apply a control agent. Aquatain, a monomolecular surface film, can be considered a suitable mosquito control agent for such breeding habitats due to its physical properties. The properties allow Aquatain to self-spread over a water surface and affect multiple stages of the mosquito life cycle. Methodology/Principal Findings A trial based on a pre-test/post-test control group design evaluated the potential of Aquatain as a mosquito control agent at Ahero rice irrigation scheme in Kenya. After Aquatain application at a dose of 2 ml/m2 on rice paddies, early stage anopheline larvae were reduced by 36%, and late stage anopheline larvae by 16%. However, even at a lower dose of 1 ml/m2 there was a 93.2% reduction in emergence of anopheline adults and 69.5% reduction in emergence of culicine adults. No pupation was observed in treated buckets that were part of a field bio-assay carried out parallel to the trial. Aquatain application saved nearly 1.7 L of water in six days from a water surface of 0.2 m2 under field conditions. Aquatain had no negative effect on rice plants as well as on a variety of non-target organisms, except backswimmers. Conclusions/Significance We demonstrated that Aquatain is an effective agent for the control of anopheline and culicine mosquitoes in irrigated rice paddies. The agent reduced densities of aquatic larval stages and, more importantly, strongly impacted the emergence of adult mosquitoes. Aquatain also reduced water loss due to evaporation. No negative impacts were found on either abundance of non-target organisms, or growth and development of rice plants. Aquatain, therefore, appears a suitable mosquito control tool for use in rice agro-ecosystems. PMID:21738774

Using non-targeted direct analysis in real time-mass spectrometry (DART-MS) to discriminate seeds based on endogenous or exogenous chemicals.

PubMed

Subbaraj, Arvind K; Barrett, Brent A; Wakelin, Steve A; Fraser, Karl

2015-10-01

Forage seeds are a highly traded agricultural commodity, and therefore, quality control and assurance is high priority. In this study, we have used direct analysis in real time-mass spectrometry (DART-MS) as a tool to discriminate forage seeds based on their non-targeted chemical profiles. In the first experiment, two lots of perennial ryegrass (Lolium perenne L.) seed were discriminated based on exogenous residues of N-(3, 4-dichlorophenyl)-N,N-dimethylurea (Diuron(TM)), a herbicide. In a separate experiment, washed and unwashed seeds of the forage legumes white clover (Trifolium repens L.) and alfalfa (Medicago sativa L.) were discriminated based on the presence or absence of oxylipins, a class of endogenous antimicrobial compounds. Unwashed seeds confer toxicity towards symbiotic, nitrogen-fixing rhizobia which are routinely coated on legume seeds before planting, resulting in reduced rhizobial count. This is the first report of automatic introduction of intact seeds in the DART ion source and detecting oxylipins using DART-MS. Apart from providing scope to investigate legume-rhizobia symbiosis further in the context of oxylipins, the results presented here will enable future studies aimed at classification of seeds based on chemicals bound to the seed coat, thereby offering an efficient screening device for industry.

Demographic processes limiting seedling recruitment in arid grassland restoration

Treesearch

Jeremy J. James; Tony J. Svejcar; Matthew J. Rinella

2011-01-01

Seeding is an important management tool in aridland restoration, but seeded species often fail to establish. Previous research has largely focused on the technical aspects of seeding with little effort directed at identifying demographic processes driving recruitment failures.

Effect-directed analysis of cold-pressed hemp, flax and canola seed oils by planar chromatography linked with (bio)assays and mass spectrometry.

PubMed

Teh, Sue-Siang; Morlock, Gertrud E

2015-11-15

Cold-pressed hemp, flax and canola seed oils are healthy oils for human consumption as these are rich in polyunsaturated fatty acids and bioactive phytochemicals. However, bioactive information on the food intake side is mainly focused on target analysis. For more comprehensive information with regard to effects, single bioactive compounds present in the seed oil extracts were detected by effect-directed assays, like bioassays or an enzymatic assay, directly linked with chromatography and further characterized by mass spectrometry. This effect-directed analysis is a streamlined method for the analysis of bioactive compounds in the seed oil extracts. All effective compounds with regard to the five assays or bioassays applied were detected in the samples, meaning also bioactive breakdown products caused during oil processing, residues or contaminants, aside the naturally present bioactive phytochemicals. The investigated cold-pressed oils contained compounds that exert antioxidative, antimicrobial, acetylcholinesterase inhibitory and estrogenic activities. This effect-directed analysis can be recommended for bioactivity profiling of food to obtain profound effect-directed information on the food intake side. Copyright © 2015 Elsevier Ltd. All rights reserved.

Seed production and dispersal by dwarf mistletoe in overstory jeffrey pines in California

Treesearch

Robert F. Scharpf; J. R. Parmeter Jr.

1971-01-01

Studies in northeastern California showed that the number of dwarf mistletoe (Arceuthobium campylopodum) seeds trapped declined at a logaithmic rate as the distance from overstory source of infection increased. The most seeds were dispersed in the direction of preuading winds. It Is quite likely that storms also aid dispersal. Total numbers of seeds...

Riparian soil seed banks and the potential for passive restoration of giant reed infested areas in Webb County, Texas

USDA-ARS?s Scientific Manuscript database

Habitat restoration projects can use seed bank information as early warning systems of patterns or degrees of habitat degradation; as changes in above ground vegetation directly impact below ground seed distribution. In multiple strategy restoration efforts, seed bank quality can be used as a decidi...

DETECTION OF GIARDIA IN ENVIRONMENTAL WATERS BY IMMUNO-PCR AMPLIFICATION METHODS

EPA Science Inventory

Genomic DNA was extracted either directly from Giardia muris cysts seeded into environmental surface waters or from cysts isolated by immunomagnetic beads (IMB).A 0.171-kbp segment of the giardin gene was PCR-amplified following "direct extraction" of Giardia DNA from seeded Caha...

DETECTION OF GIARDIA IN ENVIRONMENTAL WATERS BY IMMUNO-PCR AMPLIFICATION METHODS

EPA Science Inventory

Genomic DNA was extracted either directly from Giardia muris cysts seeded into environmental surface waters or from cysts isolated by immunomagnetic beads (IMB}. A 0.171-kbp segment of the giardin gene was PCR-amplified following "direct extraction" of Giardia DNA from seeded Cah...

TRANSPARENT TESTA GLABRA1 Regulates the Accumulation of Seed Storage Reserves in Arabidopsis1[OPEN

PubMed Central

Chen, Mingxun; Zhang, Bin; Li, Chengxiang; Kulaveerasingam, Harikrishna; Chew, Fook Tim; Yu, Hao

2015-01-01

Seed storage reserves mainly consist of starch, triacylglycerols, and storage proteins. They not only provide energy for seed germination and seedling establishment, but also supply essential dietary nutrients for human beings and animals. So far, the regulatory networks that govern the accumulation of seed storage reserves in plants are still largely unknown. Here, we show that TRANSPARENT TESTA GLABRA1 (TTG1), which encodes a WD40 repeat transcription factor involved in many aspects of plant development, plays an important role in mediating the accumulation of seed storage reserves in Arabidopsis (Arabidopsis thaliana). The dry weight of ttg1-1 embryos significantly increases compared with that of wild-type embryos, which is accompanied by an increase in the contents of starch, total protein, and fatty acids in ttg1-1 seeds. FUSCA3 (FUS3), a master regulator of seed maturation, binds directly to the TTG1 genomic region and suppresses TTG1 expression in developing seeds. TTG1 negatively regulates the accumulation of seed storage proteins partially through transcriptional repression of 2S3, a gene encoding a 2S albumin precursor. TTG1 also indirectly suppresses the expression of genes involved in either seed development or synthesis/modification of fatty acids in developing seeds. In addition, we demonstrate that the maternal allele of the TTG1 gene suppresses the accumulation of storage proteins and fatty acids in seeds. Our results suggest that TTG1 is a direct target of FUS3 in the framework of the regulatory hierarchy controlling seed filling and regulates the accumulation of seed storage proteins and fatty acids during the seed maturation process. PMID:26152712

TRANSPARENT TESTA GLABRA1 Regulates the Accumulation of Seed Storage Reserves in Arabidopsis.

PubMed

Chen, Mingxun; Zhang, Bin; Li, Chengxiang; Kulaveerasingam, Harikrishna; Chew, Fook Tim; Yu, Hao

2015-09-01

Seed storage reserves mainly consist of starch, triacylglycerols, and storage proteins. They not only provide energy for seed germination and seedling establishment, but also supply essential dietary nutrients for human beings and animals. So far, the regulatory networks that govern the accumulation of seed storage reserves in plants are still largely unknown. Here, we show that TRANSPARENT TESTA GLABRA1 (TTG1), which encodes a WD40 repeat transcription factor involved in many aspects of plant development, plays an important role in mediating the accumulation of seed storage reserves in Arabidopsis (Arabidopsis thaliana). The dry weight of ttg1-1 embryos significantly increases compared with that of wild-type embryos, which is accompanied by an increase in the contents of starch, total protein, and fatty acids in ttg1-1 seeds. FUSCA3 (FUS3), a master regulator of seed maturation, binds directly to the TTG1 genomic region and suppresses TTG1 expression in developing seeds. TTG1 negatively regulates the accumulation of seed storage proteins partially through transcriptional repression of 2S3, a gene encoding a 2S albumin precursor. TTG1 also indirectly suppresses the expression of genes involved in either seed development or synthesis/modification of fatty acids in developing seeds. In addition, we demonstrate that the maternal allele of the TTG1 gene suppresses the accumulation of storage proteins and fatty acids in seeds. Our results suggest that TTG1 is a direct target of FUS3 in the framework of the regulatory hierarchy controlling seed filling and regulates the accumulation of seed storage proteins and fatty acids during the seed maturation process. © 2015 American Society of Plant Biologists. All Rights Reserved.

Liquid chromatographic-diode-array detection multiresidue determination of rice herbicides in drinking and paddy-field water.

PubMed

Roehrs, Rafael; Zanella, Renato; Pizzuti, Ionara; Adaime, Martha B; Pareja, Lucía; Niell, Silvina; Cesio, María V; Heinzen, Horacio

2009-01-01

A sensitive, rapid, and simple multiresidue method for the simultaneous determination of six postemergence herbicides currently used in rice cultivation--metsulfuron methyl, bensulfuron methyl, pyrazosulfuron ethyl, bentazone, bispyribac sodium, and cyhalofop butyl--in drinking and paddy-field water is presented. Water samples were extracted with solid-phase extraction cartridges. Final determination was made by LC with diode-array detection. The extraction efficiencies of C18 and HLB cartridges were compared. The average recovery obtained for these compounds for the lowest spiked level (0.1 microg/L) varied from 70 to 122% for C18 and 75-119% for HLB, with RSDs of 11 and 8.3%, respectively. The method had good linearity, and the lower detection limit for the pesticides studied varied from 0.03 to 0.04 microg/L. The proposed method was also tested in paddy-field water, with recovery studies giving good results with low RSDs at 1.0 microg/L.

Phytoremediation of arsenic contaminated paddy soils with Pteris vittata markedly reduces arsenic uptake by rice.

PubMed

Ye, Wen-Ling; Khan, M Asaduzzaman; McGrath, Steve P; Zhao, Fang-Jie

2011-12-01

Arsenic (As) accumulation in food crops such as rice is of major concern. To investigate whether phytoremediation can reduce As uptake by rice, the As hyperaccumulator Pteris vittata was grown in five contaminated paddy soils in a pot experiment. Over a 9-month period P. vittata removed 3.5-11.4% of the total soil As, and decreased phosphate-extractable As and soil pore water As by 11-38% and 18-77%, respectively. Rice grown following P. vittata had significantly lower As concentrations in straw and grain, being 17-82% and 22-58% of those in the control, respectively. Phytoremediation also resulted in significant changes in As speciation in rice grain by greatly decreasing the concentration of dimethylarsinic acid (DMA). In two soils the concentration of inorganic As in rice grain was decreased by 50-58%. The results demonstrate an effective stripping of bioavailable As from contaminated paddy soils thus reducing As uptake by rice. Copyright © 2011 Elsevier Ltd. All rights reserved.

Groundwater-soil-crop relationship with respect to arsenic contamination in farming villages of Bangladesh--a preliminary study.

PubMed

Kurosawa, Kiyoshi; Egashira, Kazuhiko; Tani, Masakazu; Jahiruddin, M; Moslehuddin, Abu Zofar Md; Rahman, Zulfikar Md

2008-11-01

To clarify the groundwater-soil-crop relationship with respect to arsenic (As) contamination, As concentration was measured in tubewell (TW) water, surface soil from farmyards and paddy fields, and fresh taro (Colocasia esculenta) leaves from farmyards in the farming villages of Bangladesh. The As concentration in TW water from farmyards was at least four times higher than the Bangladesh drinking water standard, and the concentration in fresh taro leaves was equal to or higher than those reported previously for leafy vegetables in Bangladesh. As concentration of surface soils in both farmyards and paddy fields was positively correlated with that of the TW water. Further, the concentration in surface soil was positively correlated with levels in fresh taro leaves in the farmyard. This study, therefore, clarified the groundwater-soil-crop relationship in farmyards and the relationship between groundwater-soil in paddy fields to assess the extent of As contamination in Bangladeshi villages.

Modelling Water Flow through Paddy Soils under Alternate Wetting and Drying Irrigation Practice

NASA Astrophysics Data System (ADS)

Shekhar, S.; Mailapalli, D. R.; Das, B. S.; Raghuwanshi, N. S.

2017-12-01

Alternate wetting and drying (AWD) irrigation practice in paddy cultivation requires an optimum soil moisture stress (OSMS) level at which irrigation water savings can be maximized without compromising the yield reduction. Determining OSMS experimentally is challenging and only possible with appropriate modeling tools. In this study, field experiments on paddy were conducted in thirty non-weighing type lysimeters during dry seasons of 2016 and 2017. Ten plots were irrigated using continuous flooding (CF) and the rest were irrigated with AWD practice at 40mb and 75mb soil moisture stress levels. Depth of ponding and soil suction at 10, 40 and 70 cm from the soil surface were measured daily from all lysimeter plots. The measured field data were used in calibration and validation of Hydrus-1D model and simulated the water flow for both AWD and CF plots. The Hydrus-1D is being used to estimate OSMS for AWD practice and compared the seasonal irrigation water input and deep percolation losses with CF practice.

Occurrence and distribution study of residues from pesticides applied under controlled conditions in the field during rice processing.

PubMed

Pareja, Lucía; Colazzo, Marcos; Pérez-Parada, Andrés; Besil, Natalia; Heinzen, Horacio; Böcking, Bernardo; Cesio, Verónica; Fernández-Alba, Amadeo R

2012-05-09

The results of an experiment to study the occurrence and distribution of pesticide residues during rice cropping and processing are reported. Four herbicides, nine fungicides, and two insecticides (azoxystrobin, byspiribac-sodium, carbendazim, clomazone, difenoconazole, epoxiconazole, isoprothiolane, kresoxim-methyl, propanil, quinclorac, tebuconazole, thiamethoxam, tricyclazole, trifloxystrobin, λ-cyhalotrin) were applied to an isolated rice-crop plot under controlled conditions, during the 2009-2010 cropping season in Uruguay. Paddy rice was harvested and industrially processed to brown rice, white rice, and rice bran, which were analyzed for pesticide residues using the original QuEChERS methodology and its citrate variation by LC-MS/MS and GC-MS. The distribution of pesticide residues was uneven among the different matrices. Ten different pesticide residues were found in paddy rice, seven in brown rice, and eight in rice bran. The highest concentrations were detected in paddy rice. These results provide information regarding the fate of pesticides in the rice food chain and its safety for consumers.

Distribution and identification of proteolytic Bacillus spp. in paddy field soil under rice cultivation.

PubMed

Watanabe, K; Hayano, K

1993-07-01

Proteolytic bacteria in paddy field soils under rice cultivation were characterized and enumerated using azocoll agar plates. Bacillus spp. were the proteolytic bacteria that were most frequently present, comprising 59% of the isolates. They were always the numerically dominant proteolytic bacteria isolated from three kinds of fertilizer treatments (yearly application of rice-straw compost and chemical fertilizer, yearly application of chemical fertilizer, and no fertilizer application) and at three different stages of rice development (vegetative growth stage, maximal tillering stage, and harvest stage). Of the 411 proteolytic bacteria isolated, 124 isolates had stronger proteolytic activity than others on the basis of gelatin liquefaction tests and most of them were Bacillus spp. (100% in 1989 and 92.4% in 1991). Bacillus subtilis and Bacillus cereus were the main bacteria of this group and Bacillus mycoides, Bacillus licheniformis, and Bacillus megaterium were also present. We conclude that these Bacillus spp. are the primary source of soil protease in these paddy fields.

Myrmecochory and short-term seed fate in Rhamnus alaternus: Ant species and seed characteristics

NASA Astrophysics Data System (ADS)

Bas, J. M.; Oliveras, J.; Gómez, C.

2009-05-01

Benefits conferred on plants in ant-mediated seed dispersal mutualisms (myrmecochory) depend on the fate of transported seeds. We studied the effects of elaiosome presence, seed size and seed treatment (with and without passage through a bird's digestive tract) on short-term seed fate in Rhamnus alaternus. In our study, we define short-term seed, or initial, seed fate, as the location where ants release the seeds after ant contact with it. The elaiosomes had the most influence on short-term fate, i.e. whether or not seeds were transported to the nest. The workers usually transported big seeds more often than small ones, but small ants did not transport large seeds. Effect of seed size on transport depended on the ant species and on the treatment of the seed (manual extraction simulating a direct fall from the parent plant vs. bird deposition corresponding to preliminary primary dispersal). Probability of removal of elaiosome-bearing seeds to the nest by Aphaenogaster senilis increased with increasing seed weight.

An index of ripeness for sugar pine seed

Treesearch

H.A. Fowells

1949-01-01

Immature or unripe seed may be one cause of the poor germination of sugar pine occasionally experienced in nursery practice or direct seeding projects. Ripeness of pine seed, or the time to harvest cones, is usually judged by a change from green to brown in the color of cones or by the development of a firm consistency in the endosperm. However accurately these...

Ponderosa pine seeding trials in west-side Sierra Nevada clearcuts: some early results

Treesearch

Robert L. Neal

1975-01-01

In direct-seeding trials on the Challenge Experimental Forest, Yuba County, California, 27 combinations of seeding rates, aspect, and site treatment were tested. The best results were obtained on northerly aspects on unburned mechanically disturbed seedbeds with a high proportion of exposed mineral soil when seed application rates were high. Sowing at least 1 pound of...

Direct measurement of the pulse duration and frequency chirp of seeded XUV free electron laser pulses

NASA Astrophysics Data System (ADS)

Azima, Armin; Bödewadt, Jörn; Becker, Oliver; Düsterer, Stefan; Ekanayake, Nagitha; Ivanov, Rosen; Kazemi, Mehdi M.; Lamberto Lazzarino, Leslie; Lechner, Christoph; Maltezopoulos, Theophilos; Manschwetus, Bastian; Miltchev, Velizar; Müller, Jost; Plath, Tim; Przystawik, Andreas; Wieland, Marek; Assmann, Ralph; Hartl, Ingmar; Laarmann, Tim; Rossbach, Jörg; Wurth, Wilfried; Drescher, Markus

2018-01-01

We report on a direct time-domain measurement of the temporal properties of a seeded free-electron laser pulse in the extreme ultraviolet spectral range. Utilizing the oscillating electromagnetic field of terahertz radiation, a single-shot THz streak-camera was applied for measuring the duration as well as spectral phase of the generated intense XUV pulses. The experiment was conducted at FLASH, the free electron laser user facility at DESY in Hamburg, Germany. In contrast to indirect methods, this approach directly resolves and visualizes the frequency chirp of a seeded free-electron laser (FEL) pulse. The reported diagnostic capability is a prerequisite to tailor amplitude, phase and frequency distributions of FEL beams on demand. In particular, it opens up a new window of opportunities for advanced coherent spectroscopic studies making use of the high degree of temporal coherence expected from a seeded FEL pulse.

Direct seeding for forestation

Treesearch

Walter H. Davidson

1980-01-01

Direct seeding, an attractive alternative to planting, is not a simple method of forestation. Past experiences show far more failures than successes. Well documented procedures must be followed to insure any degree of success. In general, conifers have given the best results. Black walnut and black locust are notable exceptions. Current research suggests that other...

CRP Takeout: An Excellent Opportunity to Begin Direct Seeding

USDA-ARS?s Scientific Manuscript database

Lands returning to production after enrollment in CRP can be managed to maintain the many improvements in soil quality that have occurred over the life of the CRP contract, such as higher organic matter, increased water infiltration and improved soil structure. Direct seeding may be a viable managem...

A three-season field study on the in-situ remediation of Cd-contaminated paddy soil using lime, two industrial by-products, and a low-Cd-accumulation rice cultivar.

PubMed

Yan-Bing, He; Dao-You, Huang; Qi-Hong, Zhu; Shuai, Wang; Shou-Long, Liu; Hai-Bo, He; Han-Hua, Zhu; Chao, Xu

2017-02-01

To mitigate the serious problem of Cd-contaminated paddy soil, we investigated the remediation potential of combining in-situ immobilization with a low-Cd-accumulation rice cultivar. A three-season field experiment compared the soil pH, available Cd and absorption of Cd by three rice cultivars with different Cd accumulation abilities grown in Cd-contaminated paddy soil amended with lime (L), slag (S), and bagasse (B) alone or in combination. The three amendments applied alone and in combination significantly increased soil pH, reduced available Cd and absorption of Cd by rice with no effect on grain yield. Among these, the LS and LSB treatments reduced the brown rice Cd content by 38.3-69.1% and 58.3-70.9%, respectively, during the three seasons. Combined with planting of a low-Cd-accumulation rice cultivar (Xiang Zaoxian 32) resulted in a Cd content in brown rice that met the contaminant limit (≤0.2mgkg -1 ). However, the grain yield of the low-Cd-accumulation rice cultivar was approximately 30% lower than the other two rice cultivars. Applying LS or LSB as amendments combined with planting a low-Cd-accumulation rice cultivar is recommended for the remediation of Cd-contaminated paddy soil. The selection and breeding of low-Cd-accumulation rice cultivars with high grain production requires further research. Copyright © 2016 Elsevier Inc. All rights reserved.

Remediation mechanisms for Cd-contaminated soil using natural sepiolite at the field scale.

PubMed

Yin, Xiuling; Xu, Yingming; Huang, Rong; Huang, Qingqing; Xie, Zhonglei; Cai, Yanming; Liang, Xuefeng

2017-12-13

Remediation of heavy metal polluted agricultural soil is essential for human health and ecological safety and remediation mechanisms at the microscopic level are vital for their large-scale utilization. In this study, natural sepiolite was employed as an immobilization agent for in situ field-scale remediation of Cd-contaminated paddy soil and the remediation mechanisms were investigated in terms of soil chemistry and plant physiology. Natural sepiolite had a significant immobilization effect for bioavailable Cd contents in paddy soil, and consequently could lower the Cd concentrations of brown rice, husk, straw, and roots of rice plants by 54.7-73.7%, 44.0-62.5%, 26.5-67.2%, and 36.7-46.7%, respectively. Regarding soil chemistry, natural sepiolite increased the soil pH values and shifted the zeta potentials of soil particles to be more negative, enhancing the fixation or sorption of Cd on soil particles, and resulted in the reduction of HCl and DTPA extractable Cd concentrations in paddy soil. Natural sepiolite neither enhanced nor inhibited iron plaques on the rice root surface, but did change the chemical environments of Fe and S in rice root. Natural sepiolite improved the activities of antioxidant enzymes and enhanced the total antioxidant capacity to alleviate the stress of Cd. It also promotes the synthesis of GSH and NPT to complete the detoxification. In general, the remediation mechanisms of natural sepiolite for the Cd pollutant in paddy soil could be summarized as the collective effects of soil chemistry and plant physiology.

Benefits of Red-Edge Spectral Band and Texture Features for the Object-based Classification using RapidEye sSatellite Image data

NASA Astrophysics Data System (ADS)

Kim, H. O.; Yeom, J. M.

2014-12-01

Space-based remote sensing in agriculture is particularly relevant to issues such as global climate change, food security, and precision agriculture. Recent satellite missions have opened up new perspectives by offering high spatial resolution, various spectral properties, and fast revisit rates to the same regions. Here, we examine the utility of broadband red-edge spectral information in multispectral satellite image data for classifying paddy rice crops in South Korea. Additionally, we examine how object-based spectral features affect the classification of paddy rice growth stages. For the analysis, two seasons of RapidEye satellite image data were used. The results showed that the broadband red-edge information slightly improved the classification accuracy of the crop condition in heterogeneous paddy rice crop environments, particularly when single-season image data were used. This positive effect appeared to be offset by the multi-temporal image data. Additional texture information brought only a minor improvement or a slight decline, although it is well known to be advantageous for object-based classification in general. We conclude that broadband red-edge information derived from conventional multispectral satellite data has the potential to improve space-based crop monitoring. Because the positive or negative effects of texture features for object-based crop classification could barely be interpreted, the relationships between the textual properties and paddy rice crop parameters at the field scale should be further examined in depth.

Converting Paddy Rice Field to Urban Use Dramatically Altered the Water and Energy Balances in Southern China

NASA Astrophysics Data System (ADS)

Hao, L.; Sun, G.; Liu, Y.; Qin, M.; Huang, X.; Fang, D.

2017-12-01

Paddy rice wetlands are the main land use type across southern China, which impact the regional environments by affecting evapotranspiration (ET) and other water and energy related processes. Our study focuses on the effects of land-cover change on water and energy processes in the Qinhuai River Basin, a typical subtropical humid region that is under rapid ecological and economical transformations. This study integrates multiple methods and techniques including remote sensing, water and energy balance model (i.e., Surface Energy Balance Algorithm for Land, SEBAL), ecohydrological model (i.e., Soil and Water Assessment Tool, SWAT), and ground observation (Eddy Covariance measurement, etc.). We found that conversion of paddy rice field to urban use led to rise in vapor pressure deficit (VPD) and reduction in ET, and thus resulted in changes in local and regional water and heat balance. The effects of the land-use change on ET and VPD overwhelmed the effects of regional climate warming and climate variability. We conclude that the ongoing large-scale urbanization of the rice paddy-dominated regions in humid southern China and East Asia will likely exacerbate environmental consequences (e.g., elevated storm-flow volume, aggravated flood risks, and intensified urban heat island and urban dry island effects). The potential role of vegetated land cover in moderating water and energy balances and maintaining a stable climate should be considered in massive urban planning and global change impact assessment in southern China.

Arsenic mitigation in paddy soils by using microbial fuel cells.

PubMed

Gustave, Williamson; Yuan, Zhao-Feng; Sekar, Raju; Chang, Hu-Cheng; Zhang, Jun; Wells, Mona; Ren, Yu-Xiang; Chen, Zheng

2018-07-01

Arsenic (As) behavior in paddy soils couples with the redox process of iron (Fe) minerals. When soil is flooded, Fe oxides are transformed to soluble ferrous ions by accepting the electrons from Fe reducers. This process can significantly affect the fate of As in paddy fields. In this study, we show a novel technique to manipulate the Fe redox processes in paddy soils by deploying soil microbial fuel cells (sMFC). The results showed that the sMFC bioanode can significantly decrease the release of Fe and As into soil porewater. Iron and As contents around sMFC anode were 65.0% and 47.0% of the control respectively at day 50. The observed phenomenon would be explained by a competition for organic substrate between sMFC bioanode and the iron- and arsenic-reducing bacteria in the soils. In the vicinity of bioanode, organic matter removal efficiencies were 10.3% and 14.0% higher than the control for lost on ignition carbon and total organic carbon respectively. Sequencing of the 16S rRNA genes suggested that the influence of bioanodes on bulk soil bacterial community structure was minimal. Moreover, during the experiment a maximum current and power density of 0.31 mA and 12.0 mWm -2 were obtained, respectively. This study shows a novel way to limit the release of Fe and As in soils porewater and simultaneously generate electricity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Carbon and water cycling in flooded and rainfed rice (Oryza Sativa) ecosystem: Disentangling agronomical and ecological aspects of water use efficiency

NASA Astrophysics Data System (ADS)

Nay-Htoon, Bhone; Xue, Wei; Dubbert, Maren; Lindner, Steve; Cuntz, Matthias; Ko, Jonghan; Tenhunen, John; Werner, Christiane

2015-04-01

Agricultural crops play an important role in the global carbon and water cycling process and there is intense research to understand and predict carbon and water fluxes, productivity and water use of cultivated crops under climate change. Mechanistic understanding of the trade of between ecosystem water use efficiency and agronomic water use efficiency to maintain higher crop yield and productive water loss is necessary for the ecosystem sustainability. . We compared water and carbon fluxes of paddy and rainfed rice by canopy scale gas exchange measurements, crop growth, and daily evapotranspiration, transpiration and carbon flux modeling. According to our findings, evaporation contributed strongly (maximum 100% to minimum 45%) to paddy rice evapotranspiration while transpiration of rainfed is almost 50 % of daily evapotranspiration. Water use efficiency (WUE) was higher in rainfed rice both from an agronomic (WUEagro, i.e. grain yield per evapotranspiration) and ecosystem (WUEeco, i.e. gross primary production per evapotranspiration) perspective. However, rainfed rice showed also high ecosystem respiration losses and a slightly lower crop yield, demonstrating that higher WUE in rainfed rice comes at the expense of higher respiration losses of assimilated carbon and lower plant production, compared to paddy rice. Our results highlighted the need to partition water and carbon fluxes to improve our mechanistic understanding of water use efficiency and environmental impact of different agricultural practices. Keywords: Rainfed rice, Paddy rice, water use efficiency, Transpiration/Evapotranspiration, ecosystem WUE, agronomic WUE, Evapotranspiration

Shifts in indigenous microbial communities during the anaerobic degradation of pentachlorophenol in upland and paddy soils from southern China.

PubMed

Chen, Yating; Tao, Liang; Wu, Ke; Wang, Yongkui

2016-11-01

Pentachlorophenol (PCP) is a common persistent pesticide in soil that has generated a significant environmental problem worldwide. Therefore, anaerobic degradation of PCP by the soil indigenous microbial community has gained increasing attention. However, little information is available concerning the functional microorganisms and the potential shifts in the microbial community associated with PCP degradation. In this study, we conducted a set of experiments to determine which components of the indigenous microbial community were capable of degrading PCP in soils of two land use types (upland and paddy soils) in southern China. Our results showed that the PCP degradation rate was significantly higher in paddy soils than that in upland soils. 16S ribosomal RNA (rRNA) high-throughput sequencing revealed significant differences in microbial taxonomic composition between the soil with PCP and blank (soil without PCP) with Acinetobacter, Clostridium, Coprococcus, Oxobacter, and Sedimentibacter dominating the PCP-affected communities. Acinetobacter was also apparently enriched in the paddy soils with PCP (up to 52.2 %) indicated this genus is likely to play an important role in PCP degradation. Additionally, the Fe(III)-reducing bacteria Clostridium may also be involved in PCP degradation. Our data further revealed hitherto unknown metabolisms of potential PCP degradation by microorganisms including Coprococcus, Oxobacter, and Ruminiclostridium. Overall, these findings indicated that land use types may affect the PCP anaerobic degradation rate via the activities of indigenous bacterial populations and extend our knowledge of the bacterial populations responsible for PCP degradation.

Using 13C isotopes to explore denitrification-dependent anaerobic methane oxidation in a paddy-peatland

PubMed Central

Shi, Yao; Wang, Zhongqiang; He, Chunguang; Zhang, Xinyu; Sheng, Lianxi; Ren, Xiaodong

2017-01-01

Peatlands are organic-matter-rich but nitrogen-limited natural systems, the carbon/nitrogen (C/N) status of which are subject to increasing exposure from long-term nitrate (NO3−) fertilizer inputs and atmospheric nitrogen (N) deposits. To manage and protect these unique environments, an improved understanding of denitrification-dependent anaerobic oxidation of methane (DAMO) in peatlands is needed. In this study, we used stable isotope measurements and incubation with NO3− additions to facilitate an investigation and comparison of the potential DAMO rates in a paddy-peatland that has been influenced by N fertilizer over 40 years and an undisturbed peatland in northeast China. Monitoring of 13CO2 production confimed DAMO did occur in both the paddy-peatland and the undisturbed peatland, the rates of which increased with NO3− additions, but decreased logarithmically with time. When NO3− was added, there were no significant differences between the CH4 oxidation in the paddy-peatland and peatland samples after 36 hours of incubation (97.08 vs. 143.69 nmol g−1 dry peat) and the potential DAMO rate after incubation for 1 hour (92.53 vs. 69.99 nmol g−1 h−1). These results indicate that the occurrence of DAMO in peatlands might be controlled by the amount of NO3− applied and the depth to which it penetrates into the anoxic layer. PMID:28098207

The influence of continuous rice cultivation and different waterlogging periods on morphology, clay mineralogy, Eh, pH and K in paddy soils.

PubMed

Bahmanyar, M A

2007-09-01

The effect of different rice cultivation periods on the properties of selected soils in alluvial plain were studied in Mazandaran province (north of Iran) in 2004. Soils were sampled form 0, 6, 16, 26 and over 40 years rice cultivation fields. In each treatment three soil profiles and six nearby auger holes were studied. The present study results indicated that continuous rice cultivation have changed soil moisture regime from xeric to aquic, soil color from brown to grayish, surface horizons from mollic to ochric epipedon and soil structure changed from granular or blocky to massive. Therefore, the soil order has changed from Mollisols to Inceptisols. No illuviation and eluviation of clay minerals occurred as a consequence of rice cultivation. X-ray diffraction analysis showed that clay minerals in non-rice cultivated field were illite, vermiculite, montmorillonite, kaolinite and chlorite, but in rice field were illite, montmorillonite, kaolinite and chlorite, respectively. In contrast of montmorillonite, the amount of illite and vermiculite have been decreased by increasing periods of rice cultivation. The pH values of the saturated soil surface in six weeks past plantation have shifted toward neutrality. While Eh value of non-paddy soils were about +90 mv, surface horizons of paddy soils at field conditions had Eh value about +40, -12, -84, -122 mv, respectively. The amounts of organic matter and available Fe, Mn, Zn and Cu were increased whereas available K was decreased in paddy soils.

Drivers of spatio-temporal changes in paddy soil pH in Jiangxi Province, China from 1980 to 2010.

PubMed

Guo, Xi; Li, Hongyi; Yu, Huimin; Li, Weifeng; Ye, Yingcong; Biswas, Asim

2018-02-09

The spatio-temporal distribution soil pH is critical for understanding the productivity and long-term sustainability of our agri-ecosystem. This study quantified the spatio-temporal distribution of paddy soil pH in Jiangxi province, China, and the potential driver of the change between 1980 and 2010. Data from the Soil Survey Information of Jiangxi province (1980s) and Jiangxi Soil Testing and Fertilizer Recommendation study (2010s) were collected and categorized into six pH ranges from strongly-acidic to strongly-alkaline with unit pH differences. Changes were calculated from the maps developed using the Pedological Knowledge base for 1980s data (without geolocation) and geostatistical methods for the 2010s data (geolocated). An overall 0.6-unit decrease and a major shift of soil pH from weakly-acidic (54% → 18%) to acidic (35% → 74%) was observed over the province in a scattered fashion with concentration in the central part and the Poyang Lake area. About half of the area under paddy cultivation went through acidification by at least one pH unit and 7% by at least 2 pH units, while 40% of the area remained unchanged. Excessive fertilizer application and acid-rain intensity contributed to the acidification. Thus, a more knowledge-based and comprehensive fertilizer management should be adopted to make paddy production sustainable in the province.

Enzymes and chelating agent in cotton pretreatment.

PubMed

Csiszár, E; Losonczi, A; Szakács, G; Rusznák, I; Bezúr, L; Reicher, J

2001-08-23

Desized cotton fabric and cotton seed-coat fragments (impurities) have been treated with commercial cellulase (Celluclast 1.5 L), hemicellulase-pectinase (Viscozyme 120 L) and xylanase (Pulpzyme HC) enzymes. Seed-coat fragments hydrolyzed much faster than the cotton fabric itself. This relative difference in hydrolysis rates makes possible a direct enzymatic removal of seed-coat fragments from desized cotton fabric. Addition of chelating agents such as ethylenediamine-tetra-acetic acid (EDTA) markedly enhanced the directed enzyme action. Pretreatments carried out in acidic solution at pH 5 increased the lightness of seed-coat fragments, contrary to the samples treated in neutral medium at pH 7. Alkaline scouring resulted in darker seed-coat fragments except for the samples pretreated with Pulpzyme HC plus EDTA. This effect is similar to that observed in the biobleaching process in pulp and paper industry.

Impact of Thiamethoxam Seed Treatment on Growth and Yield of Rice, Oryza sativa.

PubMed

Lanka, S K; Senthil-Nathan, S; Blouin, D J; Stout, M J

2017-04-01

Neonicotinoid seed treatments are widely used in agriculture. In rice, Oryza sativa L., in the southern United States, neonicotinoid seed treatments are used to manage early-season populations of the rice water weevil, Lissorhoptrus oryzophilus Kuschel. In addition to their effects on pests, neonicotinoid seed treatments may benefit crop plants directly by increasing plant growth or altering plant responses to stresses. As part of an effort to assess the overall benefits of thiamethoxam seed treatment in rice, rice emergence, growth, and yield were evaluated. In a growth chamber, rice emergence from the soil was 1-2 d more rapid from treated than untreated seeds. These laboratory results were supported by field experiments that revealed higher stand counts from thiamethoxam-treated plots than from untreated plots. Yields from thiamethoxam treatments were no higher than those from untreated plots under conditions in which weevil larvae were absent, a result inconsistent with the hypothesis that thiamethoxam imparts direct yield benefits. In a series of field experiments conducted to compare the relationship between weevil larval densities and rice yields in plots treated with several rates of thiamethoxam or chlorantraniliprole (another widely used seed treatment insecticide), the relationship between weevil density and yield did not differ markedly among both seed treatments. Overall yields from both seed treatments did not differ significantly, despite more effective control in chlorantraniliprole-treated plots. These results provide strong support for effect of thiamethoxam on early-season growth of rice, but only weak support for its direct effect on rice yields. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The Japanese Marten Favors Actinidia arguta, a Forest Edge Liane as a Directed Seed Disperser.

PubMed

Yasumoto, Yui; Takatsuki, Seiki

2015-06-01

This study demonstrates the potential of the Japanese marten (Martes melampus) to serve as a directed seed disperser of Actinidia arguta, a representative forest edge liane. Fecal compositions of the Japanese marten in a western part of Tokyo, Japan were analyzed by the point-frame method. It fed on fruits in autumn (73.1%) and winter (63.0%), and the seeds of A. arguta were most frequently eaten (47.4%). Although the vegetation in the study area was dominated by forest (95.5%), seeds found in the marten feces were dominated by those of forest edge plants (92.1%), suggesting a strong selective bias, both habitat and food, toward these species. The density of marten feces was also higher at forest edges than forest interiors. A. arguta plants were more abundant at forest edges than within the forest at Afan Wood, Nagano Prefecture. These results suggest that the Japanese marten selectively uses forest edges as a location for feeding and defecation and thus functions as a directed seed disperser of A. arguta.

Rapidly differentiating grape seeds from different sources based on characteristic fingerprints using direct analysis in real time coupled with time-of-flight mass spectrometry combined with chemometrics.

PubMed

Song, Yuqiao; Liao, Jie; Dong, Junxing; Chen, Li

2015-09-01

The seeds of grapevine (Vitis vinifera) are a byproduct of wine production. To examine the potential value of grape seeds, grape seeds from seven sources were subjected to fingerprinting using direct analysis in real time coupled with time-of-flight mass spectrometry combined with chemometrics. Firstly, we listed all reported components (56 components) from grape seeds and calculated the precise m/z values of the deprotonated ions [M-H](-) . Secondly, the experimental conditions were systematically optimized based on the peak areas of total ion chromatograms of the samples. Thirdly, the seven grape seed samples were examined using the optimized method. Information about 20 grape seed components was utilized to represent characteristic fingerprints. Finally, hierarchical clustering analysis and principal component analysis were performed to analyze the data. Grape seeds from seven different sources were classified into two clusters; hierarchical clustering analysis and principal component analysis yielded similar results. The results of this study lay the foundation for appropriate utilization and exploitation of grape seed samples. Due to the absence of complicated sample preparation methods and chromatographic separation, the method developed in this study represents one of the simplest and least time-consuming methods for grape seed fingerprinting. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A simplified and powerful image processing methods to separate Thai jasmine rice and sticky rice varieties

NASA Astrophysics Data System (ADS)

Khondok, Piyoros; Sakulkalavek, Aparporn; Suwansukho, Kajpanya

2018-03-01

A simplified and powerful image processing procedures to separate the paddy of KHAW DOK MALI 105 or Thai jasmine rice and the paddy of sticky rice RD6 varieties were proposed. The procedures consist of image thresholding, image chain coding and curve fitting using polynomial function. From the fitting, three parameters of each variety, perimeters, area, and eccentricity, were calculated. Finally, the overall parameters were determined by using principal component analysis. The result shown that these procedures can be significantly separate both varieties.

Simulation of future global warming scenarios in rice paddies with an open-field warming facility

PubMed Central

2011-01-01

To simulate expected future global warming, hexagonal arrays of infrared heaters have previously been used to warm open-field canopies of upland crops such as wheat. Through the use of concrete-anchored posts, improved software, overhead wires, extensive grounding, and monitoring with a thermal camera, the technology was safely and reliably extended to paddy rice fields. The system maintained canopy temperature increases within 0.5°C of daytime and nighttime set-point differences of 1.3 and 2.7°C 67% of the time. PMID:22145582

Space ethics to test directed panspermia

NASA Astrophysics Data System (ADS)

Makukov, Maxim A.; shCherbak, Vladimir I.

2014-10-01

The hypothesis that Earth was intentionally seeded with life by a preceding extraterrestrial civilization is believed to be currently untestable. However, analysis of the situation where humans themselves embark on seeding other planetary systems motivated by survival and propagation of life reveals at least two ethical issues calling for specific solutions. Assuming that generally intelligence evolves ethically as it evolves technologically, the same considerations might be applied to test the hypothesis of directed panspermia: if life on Earth was seeded intentionally, the two ethical requirements are expected to be satisfied, what appears to be the case.

Genome-wide association study (GWAS) of coleoptile and mesocotyl elongation in rice (Oryza sativa L.)

USDA-ARS?s Scientific Manuscript database

Direct-seeding of rice without prior pre-germination is gaining popularity in rice growing countries because it requires less water and is less labor than transplanting rice seedlings. Slow emergence and poor seedling establishment of direct-seeded rice are the primary drawback of this method. Adeq...

10 Years of Native Seed Certification in Germany - a Summary.

PubMed

Mainz, Ann Kareen; Wieden, Markus

2018-06-21

Many renaturation projects and compensation areas are based on the use of seeds from regional indigenous wild plants, in the following: native or regional seeds. Despite this, such seeds make up only a small proportion of the total number of seeds used for greening projects - in Germany, for example, it is only around 1% (= 200 t/yr). Although the market for regional seeds is small, it is highly competitive. High-priced native seeds compete with flower mixes of unspecified origin and can only be differentiated from them by reliable quality seals. A quality assurance system based on seed legislation (EU Directive 2010/60, preservation mixtures) has been developed in a few European countries. However, quality assurance ends with the sale of the seeds. Thus, seed use remains unmonitored and often unsuitable material, or material foreign to the region, is planted in restoration areas. Unfortunately, nature conservation has not made seed-based restoration one of its key issues, neither at the European, nor at the national level. Currently there are many different local and regional standards, methods and private certificates that are confusing for users and which provide little continuity and predictability for producers. We recommend the establishment of an EU directive or a broadly agreed recommendation to the EU member states, spearheaded by nature conservation, which would define the standards for producing and using native seeds (e.g. harmonized regions that cross national borders, quality regulations). At the same time, wild plant interest groups should combine existing structures in order to strengthen seed-based restoration through international cooperation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Seeding and planting upland oaks

Treesearch

T. E. Russell

1971-01-01

Upland oaks can be established by seeding or planting, but additional experience is needed before these methods become economical alternatives to natural regeneration. Recently forested sites are generally more favorable than abandoned fields. Lack of repellents to protect acorns from animals severely limits direct seeding, but oaks can be planted readily by...

Impact of mustard seed meal applications on direct-seeded cucurbits and weed control

USDA-ARS?s Scientific Manuscript database

Weed control in organic production systems can be a labor intensive and expensive process. Mustard seed meal (MSM) is phytotoxic and a potential pre-emergent and preplant-incorporated organic herbicide for controlling germinating and emerging weed seedlings: unfortunately, MSM may also adversely imp...

Brassica greens herbicide screening

USDA-ARS?s Scientific Manuscript database

The objective of this study was to screen herbicides for potential use in brassica greens. Plots were in a RBD with 4 replications. The study was direct seeded on May 19, 2009 with a seeding rate of 272,000 seeds/acre (‘Savanna’ mustard). Treatments included trifluralin PPI + DCPA pre-emergence ap...

[On the similarity in the effects of different cryopreservation conditions on the growth and development of plants].

PubMed

Chetverikova, E P; Shabaeva, E V; Iashina, S G

2008-01-01

The morphological characteristics of 35 wild plant species were studied after freezing of seeds under the conditions of deep, fast, and programmed freezing (-196 degrees C) and non-deep freezing (-10 degrees C). The seeds were stored frozen for a month. The seeds of all the species were characterized by a low humidity. The field and laboratory seed germination capacity, leaf growth, the quantity and length of shoots, the quantity of generative organs, and the variability of these characteristics were studied. It was shown that the direction of changes under different cooling conditions was the same except for the laboratory germination capacity of some species. The direction was determined by the species features rather than cooling conditions.

Spatio temporal analysis of microbial habitats in soil-root interfaces

NASA Astrophysics Data System (ADS)

Eickhorst, Thilo; Schmidt, Hannes

2017-04-01

Microbial habitats in soils are formed by the arrangement and availability of inorganic and organic compounds. They can be characterized by physico-chemical parameters and the resulting colonization by microorganisms. Areas being preferably colonized are known as microbial hot spots which can be found in (bio)pores within the aggregatusphere or in the rhizosphere. The latter is directly influenced by plants i.e. the growth and activity of plant roots which has an influence on physico-chemical dynamics in the rhizosphere and can even shape plants' root microbiome. As microbial communities play an important role in nutrient cycling their response in soil-root interfaces is of great importance. Especially in complex systems such as paddy soils used for the cultivation of wetland rice the analysis of spatio-temporal aspects is important to get knowledge about their influence on the microbial dynamics in the respective habitats. But also other spatial variations on larger scales up to landscape scale may have an impact on the soil microorganisms in their habitats. This PICO presentation will introduce a set of techniques which are useful to analyze both the physico-chemical characteristics of microbial habitats and the microbial colonization and dynamics in soil-root interfaces. Examples will be given on various studies from rice cultivation in different paddy soils up to an European transect representing rhizosphere soils of selected plant species.

Procedure for rapid determination of δ15N and δ18O values of nitrate: development and application to an irrigated rice paddy watershed.

PubMed

Yada, Saeko; Nakajima, Yasuhiro; Itahashi, Sunao; Asada, Kei; Yoshikawa, Seiko; Eguchi, Sadao

2016-01-01

The dual isotope approach using the stable isotope ratios of nitrate nitrogen (δ(15)N(NO3)) and oxygen (δ(18)O(NO3)) is a strong tool for identifying the history of nitrate in various environments. Basically, a rapid procedure for determining δ(15)N(NO3) and δ(18)O(NO3) values is required to analyze many more samples quickly and thus save on the operational costs of isotope-ratio mass spectrometry (IRMS). We developed a new rapid procedure to save time by pre-treating consecutive samples of nitrous oxide microbially converted from nitrate before IRMS determination. By controlling two six-port valves of the pre-treatment system separately, IRMS determination of the current sample and backflush during the next sample pre-treatment period could be conducted simultaneously. A set of 89 samples was analyzed precisely during a 25-h continuous run (17 min per sample), giving the fastest reported processing time, and simultaneously reducing liquid nitrogen and carrier helium gas consumption by 35%. Application of the procedure to an irrigated rice paddy watershed suggested that nitrate concentrations in river waters decreased in a downstream direction, mainly because of the mixing of nitrate from different sources, without distinct evidence of denitrification. Our procedure should help with more detailed studies of nitrate formation processes in watersheds.

Culturable bacterial endophytes isolated from Mangrove tree (Rhizophora apiculata Blume) enhance seedling growth in Rice.

PubMed

Deivanai, Subramanian; Bindusara, Amitraghata Santhanam; Prabhakaran, Guruswamy; Bhore, Subhash Janardhan

2014-07-01

Endophytic bacteria do have several potential applications in medicine and in other various sectors of biotechnology including agriculture. Bacterial endophytes need to be explored for their potential applications in agricultural biotechnology. One of the potential applications of bacterial endophytes in agricultural is to enhance the growth of the agricultural crops. Hence, this study was undertaken to explore the plant growth promoting potential application of bacterial endophytes. The objective of this study was to examine the effect of endophytic bacteria from mangrove tree (Rhizophora apiculata Blume) for their efficacy in promoting seedling growth in rice. Eight endophytic bacterial isolates (EBIs) isolated from twig and petiole tissues of the mangrove were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequence homology. Separately, surface sterilized paddy seeds were treated with cell-free broth and cell suspension of the EBIs. Rice seedlings were analyzed by various bioassays and data was recorded. The gene sequences of the isolates were closely related to two genera namely, Bacillus and Pantoea. Inoculation of EBIs from R. apiculata with rice seeds resulted in accelerated root and shoot growth with significant increase in chlorophyll content. Among the isolates, Pantoea ananatis (1MSE1) and Bacillus amyloliquefaciens (3MPE1) had shown predominance of activity. Endophytic invasion was recognized by the non-host by rapid accumulation of reactive oxygen species (ROS) and was counteracted by the production of hydrogen peroxide (H2O2) and lipid peroxide. The results demonstrated that EBIs from mangrove tree can increase the fitness of the rice seedlings under controlled conditions. These research findings could be useful to enhance the seedling growth and could serve as foundation in further research on enhancing the growth of the rice crop using endophytic bacteria.

On the performance of surface renewal analysis to estimate sensible heat flux over two growing rice fields under the influence of regional advection

NASA Astrophysics Data System (ADS)

Castellví, F.; Snyder, R. L.

2009-09-01

SummaryHigh-frequency temperature data were recorded at one height and they were used in Surface Renewal (SR) analysis to estimate sensible heat flux during the full growing season of two rice fields located north-northeast of Colusa, CA (in the Sacramento Valley). One of the fields was seeded into a flooded paddy and the other was drill seeded before flooding. To minimize fetch requirements, the measurement height was selected to be close to the maximum expected canopy height. The roughness sub-layer depth was estimated to discriminate if the temperature data came from the inertial or roughness sub-layer. The equation to estimate the roughness sub-layer depth was derived by combining simple mixing-length theory, mixing-layer analogy, equations to account for stable atmospheric surface layer conditions, and semi-empirical canopy-architecture relationships. The potential for SR analysis as a method that operates in the full surface boundary layer was tested using data collected over growing vegetation at a site influenced by regional advection of sensible heat flux. The inputs used to estimate the sensible heat fluxes included air temperature sampled at 10 Hz, the mean and variance of the horizontal wind speed, the canopy height, and the plant area index for a given intermediate height of the canopy. Regardless of the stability conditions and measurement height above the canopy, sensible heat flux estimates using SR analysis gave results that were similar to those measured with the eddy covariance method. Under unstable cases, it was shown that the performance was sensitive to estimation of the roughness sub-layer depth. However, an expression was provided to select the crucial scale required for its estimation.

Dormancy, germination, emergence and ecology of Gardner saltbush (Atriplex gardneri (Moq. ) D. Dietr. ) seeds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ansley, R.J. Jr.

1983-01-01

Gardner saltbush (Atriplex gardneri (Moq.) D. Dietr.) provides valuable winter browse and is an important soil stabilizer in arid, alkaline, and saline areas of the intermountain region. However, seed dormancy and poor seedling vigor inhibit its potential for revegetation by direct seeding on disturbed lands. The objectives of this study were to 1) develop seed treatments which would overcome dormancy in Gardner saltbush seeds, 2) evaluate field establishment by direct seeding of Gardner saltbush, and 3) characterize seed dormancy, seedling vigor and some aspects of the ecology of germination in Gardner saltbush. In the laboratory, single and combined pretreatments removedmore » dormancy to varying degrees. Dormancy was completely alleviated with 15 months dry after-ripening + scarification + 24 hours washing + 4 weeks stratification. Dry after-ripening and scarification appeared to facilitate effects of washing and stratification. Physiologically, indirect evidence was obtained suggesting both embryo and seedcoat mediated dormancy occur in Gardner saltbush. Ecologically, the various levels of germination response to simulated environmental pretreatments appeared to be an adaptation of Gardner saltbush seeds to ensure a temporal dispersal of release from dormancy. This increases the probability that under natural conditions some seedlings will emerge during times when the environment is amenable to seedling survival.« less

Identification of HDA15-PIF1 as a key repression module directing the transcriptional network of seed germination in the dark.

PubMed

Gu, Dachuan; Chen, Chia-Yang; Zhao, Minglei; Zhao, Linmao; Duan, Xuewu; Duan, Jun; Wu, Keqiang; Liu, Xuncheng

2017-07-07

Light is a major external factor in regulating seed germination. Photoreceptor phytochrome B (PHYB) plays a predominant role in promoting seed germination in the initial phase after imbibition, partially by repressing phytochrome-interacting factor1 (PIF1). However, the mechanism underlying the PHYB-PIF1-mediated transcription regulation remains largely unclear. Here, we identified that histone deacetylase15 (HDA15) is a negative component of PHYB-dependent seed germination. Overexpression of HDA15 in Arabidopsis inhibits PHYB-dependent seed germination, whereas loss of function of HDA15 increases PHYB-dependent seed germination. Genetic evidence indicated that HDA15 acts downstream of PHYB and represses seed germination dependent on PIF1. Furthermore, HDA15 interacts with PIF1 both in vitro and in vivo. Genome-wide transcriptome analysis revealed that HDA15 and PIF1 co-regulate the transcription of the light-responsive genes involved in multiple hormonal signaling pathways and cellular processes in germinating seeds in the dark. In addition, PIF1 recruits HDA15 to the promoter regions of target genes and represses their expression by decreasing the histone H3 acetylation levels in the dark. Taken together, our analysis uncovered the role of histone deacetylation in the light-regulated seed germination process and identified that HDA15-PIF1 acts as a key repression module directing the transcription network of seed germination. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Identification of HDA15-PIF1 as a key repression module directing the transcriptional network of seed germination in the dark

PubMed Central

Gu, Dachuan; Chen, Chia-Yang; Zhao, Minglei; Zhao, Linmao; Duan, Xuewu

2017-01-01

Abstract Light is a major external factor in regulating seed germination. Photoreceptor phytochrome B (PHYB) plays a predominant role in promoting seed germination in the initial phase after imbibition, partially by repressing phytochrome-interacting factor1 (PIF1). However, the mechanism underlying the PHYB-PIF1-mediated transcription regulation remains largely unclear. Here, we identified that histone deacetylase15 (HDA15) is a negative component of PHYB-dependent seed germination. Overexpression of HDA15 in Arabidopsis inhibits PHYB-dependent seed germination, whereas loss of function of HDA15 increases PHYB-dependent seed germination. Genetic evidence indicated that HDA15 acts downstream of PHYB and represses seed germination dependent on PIF1. Furthermore, HDA15 interacts with PIF1 both in vitro and in vivo. Genome-wide transcriptome analysis revealed that HDA15 and PIF1 co-regulate the transcription of the light-responsive genes involved in multiple hormonal signaling pathways and cellular processes in germinating seeds in the dark. In addition, PIF1 recruits HDA15 to the promoter regions of target genes and represses their expression by decreasing the histone H3 acetylation levels in the dark. Taken together, our analysis uncovered the role of histone deacetylation in the light-regulated seed germination process and identified that HDA15-PIF1 acts as a key repression module directing the transcription network of seed germination. PMID:28444370

Pore Water Arsenic Dynamics in Rice Paddies Under Projected Future Climates

NASA Astrophysics Data System (ADS)

Plaganas, M.; Wang, T.; Muehe, E. M.; Fendorf, S. E.

2016-12-01

Rice is one of the staple crops in the world, with 50% of the global population eating rice daily. Many rice-producing regions of the world are irrigated with groundwater contaminated with arsenic (As), and in particular South and Southeast Asia, where geogenic As is leached into the groundwater. Use of groundwater pervasively high in As leads to subsequent accumulation in paddy soils. Arsenic, a toxic metalloid, also decreases rice productivity and further jeopardizes food security. Hence, rice agriculture is concerned with its productivity in a climate change impacted future and the particular impacts of arsenic on yields. However, past studies do not address the prevalence of As in paddy soils or its fate in the rhizosphere and ultimate impact on the plant. The objective of our study was to determine changes in pore water As dynamics in the rhizosphere of rice plants grown on As-contaminated paddy soil under climate conditions projected for the end of the century. In order to address this objective, we designed greenhouse chambers with today's climate and projected climate conditions for the year 2100, specifically 5°C increase in temperature and doubled concentration of atmospheric CO2. We hypothesize that the effects of climate change with these conditions will increase the mobility of As in the rhizosphere, and thus, decrease rice growth in As-bearing paddies more than, so far, expected. We examined pore water geochemistry including pH and As concentrations, and correlate that to the height of the plants. Furthermore, the dynamics of other elements in the pore water such as carbon, iron, sulfur, manganese, and silica are further evaluated for their effects on rice growth. Arsenic will have an impact on rice production and conditions induced by future climatic conditions need to be considered for food security. Considering that climate change will decrease the global agricultural output, we should urgently consider adapting our agricultural practices to aid in the mitigation of As uptake into rice and into the diets of the billions of people that depend on the consumption of rice daily.

Soil organic carbon (SOC) accumulation in rice paddies under long-term agro-ecosystem experiments in southern China - VI. Changes in microbial community structure and respiratory activity

NASA Astrophysics Data System (ADS)

Liu, D.; Liu, X.; Liu, Y.; Li, L.; Pan, G.; Crowley, D.; Tippkötter, R.

2011-02-01

Biological stabilization within accumulated soil organic carbon (SOC) has not been well understood, while its role in physical and chemical protection as well as of chemical recalcitrance had been addressed in Chinese rice paddies. In this study, topsoil samples were collected and respiratory activity measured in situ following rice harvest under different fertilization treatments of three long-term experimental sites across southern China in 2009. The SOC contents, microbial biomass carbon (SMBC) and nitrogen (SMBN) were analysed using chemical digestion and microbial community structure assessment via clony dilute plate counting methods. While SOC contents were consistently higher under compound chemical fertilization (Comp-Fert) or combined organic and inorganic fertilization (Comb-Fert) compared to N fertilization only (N-Fert), there was significantly higher fungal-bacterial ratio under Comb-Fert than under N-Fert and Comp-Fert. When subtracting the background effect under no fertilization treatment (Non-Fert), the increase both in SMBC and SMBN under fertilization treatment was found very significantly correlated to the increase in SOC over controls across the sites. Also, the ratio of culturable fungal to bacterial population numbers (F/B ratio) was well correlated with soil organic carbon contents in all samples across the sites studied. SOC accumulation favoured a build-up the microbial community with increasing fungal dominance in the rice paddies under fertilization treatments. While soil respiration rates were high under Comb-Fert as a result of enhanced microbial community build-up, the specific soil respiratory activity based on microbial biomass carbon was found in a significantly negatively correlation with the SOC contents for overall samples. Thus, a fungal-dominated microbial community seemed to slow SOC turnover, thereby favouring SOC accumulation under Comp-Fert or under Comb-Fert in the rice paddies. Therefore, the biological stabilization process is of importance in SOC sequestration in the rice paddies, operating with physical and chemical protection and chemical recalcitrance. However, sufficient understanding and prediction of SOM dynamics needs further quantitative characterization of the simultaneous operation of several mechanisms.

Land cover, land use, and climate change impacts on agriculture in southern Vietnam

NASA Astrophysics Data System (ADS)

Kontgis, Caitlin

Global environmental change is rapidly changing the surface of the Earth in varied and irrevocable ways. Across the world, land cover and land use have been altered to accommodate the needs of expanding populations, and climate change has required plant, animal, and human communities to adapt to novel climates. These changes have created unprecedented new ecosystems that affect the planet in ways that are not fully understood and difficult to predict. Of utmost concern is food security, and whether agro-ecosystems will adapt and respond to widespread changes so that growing global populations can be sustained. To understand how one staple food crop, rice, responds to global environmental change in southern Vietnam, this dissertation aims to accomplish three main tasks: (1) quantify the rate and form of urban and peri-urban expansion onto cropland using satellite imagery and demographic data, (2) track changes to annual rice paddy harvests using time series satellite data, and (3) model the potential effects of climate change on rice paddies by incorporating farmer interview data into a crop systems model. The results of these analyses show that the footprint of Ho Chi Minh City grew nearly five times between 1990 and 2012. Mismatches between urban development and population growth suggest that peri-urbanization is driven by supply-side investment, and that much of this form of land expansion has occurred near major transit routes. In the nearby Mekong River Delta, triple-cropped rice paddy area doubled between 2000 and 2010, from one-third to two-thirds of rice fields, while paddy area expanded by about 10%. These results illustrate the intensification of farming practices since Vietnam liberalized its economy, yet it is not clear whether such practices are environmentally sustainable long-term. Although triple-cropped paddy fields have expanded, future overall production is estimated to decline without the effects of CO2 fertilization. Temperatures are anticipated to increase by mid-century, and model results suggest this will cause depressed yields that cannot be offset by increased water or fertilizer. This finding emphasizes the need for a coordinated, actionable adaptation plan so that climate change does not devastate local ecosystems and livelihoods.

¹³⁷Cs in irrigation water and its effect on paddy fields in Japan after the Fukushima nuclear accident.

PubMed

Yoshikawa, Natsuki; Obara, Hitomi; Ogasa, Marie; Miyazu, Susumu; Harada, Naoki; Nonaka, Masanori

2014-05-15

There is concern that radiocesium deposited in the environment after the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011 will migrate to paddy fields through hydrological pathways and cause serious and long-lasting damage to the agricultural activities. This study was conducted in the Towa region of Nihonmatsu in the northern part of Fukushima Prefecture, Japan, (1) to quantify (137)Cs in stream water used to irrigate paddy fields by separating the dissolved and particulate components in water samples and then fractionating the particulate components bonded in different ways using a sequential extraction procedure, and (2) to determine the amounts of radiocesium newly added to paddy fields in irrigation water relative to the amounts of radiocesium already present in the fields from the deposition of atmospheric fallout immediately after the FDNPP accident. Three catchments were studied, and the (137)Cs activity concentrations in stream water samples were 79-198 mBq L(-1) under stable runoff conditions and 702-13,400 Bq L(-1) under storm runoff conditions. The residual fraction (F4, considered to be non-bioavailable) was dominant, accounting for 59.5-82.6% of the total (137)Cs activity under stable runoff conditions and 69.4-95.1% under storm runoff conditions. The (137)Cs newly added to paddy fields in irrigation water only contributed 0.03-0.05% of the amount already present in the soil (201-348 kBq m(-2)). This indicates that the (137)Cs inflow load in irrigation water is negligible compared with that already in the soil. However, the contribution from the potentially bioavailable fractions (F1+F2+F3) was one order of magnitude larger, accounting for 0.20-0.59%. The increase in the dissolved and soluble radiocesium fraction (F1) was especially large (3.0% to infinity), suggesting that radiocesium migration in irrigation water is increasing the accumulation of radiocesium in rice. Copyright © 2014 Elsevier B.V. All rights reserved.

Integrating ecosystem services trade-offs with paddy land-to-dry land decisions: A scenario approach in Erhai Lake Basin, southwest China.

PubMed

Hu, Yi'na; Peng, Jian; Liu, Yanxu; Tian, Lu

2018-06-01

Ecosystem services are the benefits people obtain from ecosystems, and ecosystem services trade-offs have been widely applied to the development of land-use policy. Although previous studies have focused on trade-offs of ecosystem services, a scenario approach has been seldom used. The scenario approach can reveal the changes of ecosystem services for different land-use patterns in the future, and is of great significance for land-use decisions and ecosystem management. Based on the actual situation of deteriorating water quality and dwindling water supply in the Erhai Lake Basin of southwest China, this study put forward to convert paddy land to dry land (PLDL) in the basin, and simulated its potential impact on ecosystem services. Taking environmental pollution, social impact, economic benefit and residential participation into consideration, four scenarios of PLDL were designed. Then, four ecosystem services (water purification, water yield, soil conservation and rice production) were calculated for each scenario. The optimal scenario of PLDL in the Erhai Lake Basin was identified by trade-offs of the four ecosystem services. The results showed that the total nitrogen export could be reduced by 42.07% and water yield can be increased by 5.61% after converting 100% of paddy lands to dry land, thereby greatly improving the water quality and increasing the water yield of Erhai Lake. However, PLDL involving 100% of paddy lands also increased the sediment export by 17.22%, and eliminated rice production in the region. By comparing the four PLDL scenarios for converting just 50% of paddy lands, the residential participation scenario was identified to be the best choice for PLDL implementation because it achieved the best level of water purification and had the smallest negative effect on other ecosystem services. The optimal scenario for each township showed spatial differentiation, and there were conflicts between the optimal scenarios at basin scale and township scale, suggesting that the object and the spatial-temporal scale should be taken into consideration in land-use decisions using ecosystem services trade-offs. Copyright © 2018 Elsevier B.V. All rights reserved.

Stabilized diode seed laser for flight and space-based remote lidar sensing applications

NASA Astrophysics Data System (ADS)

McNeil, Shirley; Pandit, Pushkar; Battle, Philip; Rudd, Joe; Hovis, Floyd

2017-08-01

AdvR, through support of the NASA SBIR program, has developed fiber-based components and sub-systems that are routinely used on NASA's airborne missions, and is now developing an environmentally hardened, diode-based, locked wavelength, seed laser for future space-based high spectral resolution lidar applications. The seed laser source utilizes a fiber-coupled diode laser, a fiber-coupled, calibrated iodine reference module to provide an absolute wavelength reference, and an integrated, dual-element, nonlinear optical waveguide component for second harmonic generation, spectral formatting and wavelength locking. The diode laser operates over a range close to 1064.5 nm, provides for stabilization of the seed to the desired iodine transition and allows for a highly-efficient, fully-integrated seed source that is well-suited for use in airborne and space-based environments. A summary of component level environmental testing and spectral purity measurements with a seeded Nd:YAG laser will be presented. A direct-diode, wavelength-locked seed laser will reduce the overall size weight and power (SWaP) requirements of the laser transmitter, thus directly addressing the need for developing compact, efficient, lidar component technologies for use in airborne and space-based environments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schuman, G.E.; Vicklund, L.E.; Belden, S.E.

In 1996, the Wyoming Department of Environmental Quality enacted regulations governing the reestablishment of woody shrubs on mined lands. The regulation required that an average density of one shrub m{sup -2} be reestablished on at least 20% of the disturbed land area and that the shrub composition must include dominant premine species. In Wyoming, and much of the Northern Great Plains, that meant that Artemisia tridentata Nutt. ssp. wyomingensis (Beetle and Young) (Wyoming big sagebrush) had to be reestablished on mined lands. Artemisia tridentata Nutt. ssp. wyomingensis had proven difficult to reestablish on mined lands because of poor quality seed,more » seed dormancy and a poor understanding of the seedbed ecology of this species. Research in the last two decades has produced significant knowledge in the area of direct-seed establishment of Artemisia tridentata Nutt. ssp. wyomingensis on mined lands. Our research has shown that reducing grass seeding rates will reduce competition and result in larger sagebrush plants that are more likely to survive and provide greater structural diversity to the plant community. Economic analyses demonstrated that big sagebrush can be established at a cost of $0.01-0.05 per seedling using direct seeding methods compared to transplanting nursery grown seedlings, estimated to cost $0.72-$1.65 per seedling (depending on size) to grow and from $1.30-$2.40 to plant (flat land to 2:1 slopes). An adequate level of precipitation will be necessary to ensure successful establishment of this species no matter what method of propagation is selected and direct seeding gives greater opportunity for success because of the demonstrated longevity of the seed to germinate 3-5 years after the initial seeding.« less

Amendment damages the function of continuous flooding in decreasing Cd and Pb uptake by rice in acid paddy soil.

PubMed

Ye, Xinxin; Li, Hongying; Zhang, Ligan; Chai, Rushan; Tu, Renfeng; Gao, Hongjian

2018-01-01

Combinations of remediation technologies are needed to solve the problem of soil contamination in paddy rice, due to multiple potential toxic elements (PTEs). Two potential mitigation methods, water management and in-situ remediation by soil amendment, have been widely used in treatment of PTE-polluted paddy soil. However, the interactive relationship between soil amendment and water management, and its influence on the accumulation of PTEs in rice are poorly understood. Greenhouse pot experiments were conducted to examine the effects of phosphate amendment on Cd and Pb availability in soil and their influence on Cd and Pb uptake into rice, on Fe and P availability in soil, and on the alteration of Fe amount and compartment on root surface among different water management strategies. Results indicated that Cd and Pb content in the shoot and grain were significantly affected by the different water management strategies in nonamended soils, and followed the order: wetting irrigation > conventional irrigation > continuous flooding. The application of phosphate amendment significantly decreased the variations of Cd and Pb absorption in shoot and grain of rice among different water treatments. The reasons may be attributed to the enhancement of P availability and the decrease of Fe availability in soil, and the decreased variations of Fe 2+ /Fe 3+ content in root coating after the application of phosphate amendment. These results suggested that the simultaneous use of phosphate amendment and continuous flooding to immobilize Cd and Pb, especially in acid paddy soils, should be avoided. Copyright © 2017 Elsevier Inc. All rights reserved.

In Situ Measurement of Some Soil Properties in Paddy Soil Using Visible and Near-Infrared Spectroscopy

PubMed Central

Wenjun, Ji; Zhou, Shi; Jingyi, Huang; Shuo, Li

2014-01-01

In situ measurements with visible and near-infrared spectroscopy (vis-NIR) provide an efficient way for acquiring soil information of paddy soils in the short time gap between the harvest and following rotation. The aim of this study was to evaluate its feasibility to predict a series of soil properties including organic matter (OM), organic carbon (OC), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), available potassium (AK) and pH of paddy soils in Zhejiang province, China. Firstly, the linear partial least squares regression (PLSR) was performed on the in situ spectra and the predictions were compared to those with laboratory-based recorded spectra. Then, the non-linear least-square support vector machine (LS-SVM) algorithm was carried out aiming to extract more useful information from the in situ spectra and improve predictions. Results show that in terms of OC, OM, TN, AN and pH, (i) the predictions were worse using in situ spectra compared to laboratory-based spectra with PLSR algorithm (ii) the prediction accuracy using LS-SVM (R2>0.75, RPD>1.90) was obviously improved with in situ vis-NIR spectra compared to PLSR algorithm, and comparable or even better than results generated using laboratory-based spectra with PLSR; (iii) in terms of AP and AK, poor predictions were obtained with in situ spectra (R2<0.5, RPD<1.50) either using PLSR or LS-SVM. The results highlight the use of LS-SVM for in situ vis-NIR spectroscopic estimation of soil properties of paddy soils. PMID:25153132

Effect of nitrogen fertilizer and/or rice straw amendment on methanogenic archaeal communities and methane production from a rice paddy soil.

PubMed

Bao, Qiongli; Huang, Yizong; Wang, Fenghua; Nie, Sanan; Nicol, Graeme W; Yao, Huaiying; Ding, Longjun

2016-07-01

Nitrogen fertilization and returning straw to paddy soil are important factors that regulate CH4 production. To evaluate the effect of rice straw and/or nitrate amendment on methanogens, a paddy soil was anaerobically incubated for 40 days. The results indicated that while straw addition increased CH4 production and the abundances of mcrA genes and their transcripts, nitrate amendment showed inhibitory effects on them. The terminal restriction fragment length polymorphism (T-RFLP) analysis based on mcrA gene revealed that straw addition obviously changed methanogenic community structure. Based on mcrA gene level, straw-alone addition stimulated Methanosarcinaceaes at the early stage of incubation (first 11 days), but nitrate showed inhibitory effect. The relative abundance of Methanobacteriaceae was also stimulated by straw addition during the first 11 days. Furthermore, Methanosaetaceae were enriched by nitrate-alone addition after 11 days, while Methanocellaceae were enriched by nitrate addition especially within the first 5 days. The transcriptional methanogenic community indicated more dynamic and complicated responses to straw and/or nitrate addition. Based on mcrA transcript level, nitrate addition alone resulted in the increase of Methanocellaceae and the shift from Methanosarcinaceae to Methanosaetaceae during the first 5 days of incubation. Straw treatments increased the relative abundance of Methanobacteriaceae after 11 days. These results demonstrate that nitrate addition influences methanogens which are transcriptionally and functionally active and can alleviate CH4 production associated with straw amendment in paddy soil incubations, presumably through competition for common substrates between nitrate-utilizing organisms and methanogens.

Estimation of soil-to-plant transfer factors of radiocesium in 99 wild plant species grown in arable lands 1 year after the Fukushima 1 Nuclear Power Plant accident.

PubMed

Yamashita, Jun; Enomoto, Takashi; Yamada, Masao; Ono, Toshiro; Hanafusa, Tadashi; Nagamatsu, Tomohiro; Sonoda, Shoji; Yamamoto, Yoko

2014-01-01

One year after the deposition of radionuclides from the Fukushima 1 Nuclear Power Plant (A formal name is Fukushima Daiichi Nuclear Power Station) in March 2011, radiocesium (¹³⁴Cs, ¹³⁷Cs) concentrations ([Cs]) were comprehensively investigated in the wild plants of 99 species most of which were annual or summer green perennial herbs and started to grow from April 2012 at the heavily contaminated fields of paddy (three study sites) and upland (one study site) in Fukushima Prefecture. The survey was conducted three times (April, July and October) in the year. In each site, soils (soil cores of 5-cm depth) and plants (aerial shoots) were collected for determination of [Cs] on a dry weight basis, and then the transfer factor (TF) of radiocesium from soil to plant ([Cs]plant/[Cs]soil) was estimated in each species. The [Cs] values of both soils and plants largely varied. However, some species exhibited relatively high TF values (more than 0.4) (e.g., Athyrium yokoscense, Dryopteris tokyoensis, and Cyperus brevifolius), while others exhibited almost negligible values (less than 0.01) (e.g., Salix miyabeana, Humulus scandens, and Elymus tsukushiensis). In addition, judging from the 11 species grown in both paddy and upland fields, TF values were generally higher in the paddy fields. The estimation of phytoextraction efficiency of soil radiocesium by weed communities in the paddy fields suggests that the weed community is not a practical candidate for phytoremediation technique.

Characterizations of purple non-sulfur bacteria isolated from paddy fields, and identification of strains with potential for plant growth-promotion, greenhouse gas mitigation and heavy metal bioremediation.

PubMed

Sakpirom, Jakkapan; Kantachote, Duangporn; Nunkaew, Tomorn; Khan, Eakalak

2017-04-01

This study was aimed at selecting purple non-sulfur bacteria (PNSB) isolated from various paddy fields, including Cd- and Zn-contaminated paddy fields, based on their biofertilizer properties. Among 235 PNSB isolates, strain TN110 was most effective in plant growth-promoting substance (PGPS) production, releasing 3.2 mg/L of [Formula: see text] , 4.11 mg/L of 5-aminolevulinic acid (ALA) and 3.62 mg/L of indole-3-acetic acid (IAA), and reducing methane emission up to 80%. This strain had nifH, vnfG and anfG, which are the Mo, V and Fe nitrogenase genes encoded for key enzymes in nitrogen fixation under different conditions. This strain provided 84% and 55% removal of Cd and Zn, respectively. Another isolate, TN414, not only produced PGPS (1.30 mg/L of [Formula: see text] , 0.94 mg/L of ALA and 0.65 mg/L of IAA), but was also efficient in removing both Cd and Zn at 72% and 74%, respectively. Based on 16S rDNA sequencing, strain TN110 was identified as Rhodopseudomonas palustris, while strain TN414 was Rubrivivax gelatinosus. A combination of TN110 and TN414 could potentially provide a biofertilizer, which is a greener alternative to commercial/chemical fertilizers and an agent for bioremediation of heavy metals and greenhouse gas mitigation in paddy fields. Copyright © 2016 Institut Pasteur. All rights reserved.

A Water Temperature Simulation Model for Rice Paddies With Variable Water Depths

NASA Astrophysics Data System (ADS)

Maruyama, Atsushi; Nemoto, Manabu; Hamasaki, Takahiro; Ishida, Sachinobu; Kuwagata, Tsuneo

2017-12-01

A water temperature simulation model was developed to estimate the effects of water management on the thermal environment in rice paddies. The model was based on two energy balance equations: for the ground and for the vegetation, and considered the water layer and changes in the aerodynamic properties of its surface with water depth. The model was examined with field experiments for water depths of 0 mm (drained conditions) and 100 mm (flooded condition) at two locations. Daily mean water temperatures in the flooded condition were mostly higher than in the drained condition in both locations, and the maximum difference reached 2.6°C. This difference was mainly caused by the difference in surface roughness of the ground. Heat exchange by free convection played an important role in determining water temperature. From the model simulation, the temperature difference between drained and flooded conditions was more apparent under low air temperature and small leaf area index conditions; the maximum difference reached 3°C. Most of this difference occurred when the range of water depth was lower than 50 mm. The season-long variation in modeled water temperature showed good agreement with an observation data set from rice paddies with various rice-growing seasons, for a diverse range of water depths (root mean square error of 0.8-1.0°C). The proposed model can estimate water temperature for a given water depth, irrigation, and drainage conditions, which will improve our understanding of the effect of water management on plant growth and greenhouse gas emissions through the thermal environment of rice paddies.

[Study on mechanism of SOM stabilization of paddy soils under long-term fertilizations].

PubMed

Luo, Lu; Zhou, Ping; Tong, Cheng-Li; Shi, Hui; Wu, Jin-Shui; Huang, Tie-Ping

2013-02-01

Fourier transform infrared spectroscopy (FTIR) was applied to study the structure of soil organic matter (SOM) of paddy soils under long-term different fertilization treatments. The aim was to clarify the different distribution of SOM between different fertilization methods and between topsoil and subsoil, and to explore the stability mechanism of SOM under different fertilization treatments. The results showed that the content of topsoil organic carbon (SOC) was the highest under organic-inorganic fertilizations, with the increment of SOC by 18.5%, 12.9% and 18.4% under high organic manure (HOM), low organic manure (LOM) and straw returning (STW) respectively compared with no fertilization treatment (CK). The long-term fertilizations also changed the chemical structure of SOM. As compared with CK, different fertilization treatments increased the functional group absorbing intensity of chemical resistance compounds (aliphatic, aromaticity), carbohydrate and organo-silicon compounds, which was the most distinctive under treatments of HOM, LOM and STW. For example, the absorbing intensity of alkyl was 0.30, 0.25 and 0.29 under HOM, LOM and STW, respectively. These values were increased by 87% , 56% and 81% as compared with that under CK treatment. The functional group absorbing intensity of SOM in the topsoil was stronger than that in the subsoil, with the most distinctive difference under HOM, LOM and STW treatments. The present research indicated that the enhanced chemical resistance of functional group of SOM may contribute to the high contents of SOC in the paddy soils under long-term organic-inorganic fertilizations, which also suggested a chemical stabilization mechanism of SOM in the paddy soils.

Focal species candidates for pesticide risk assessment in European rice fields: A review.

PubMed

Vallon, Martin; Dietzen, Christian; Laucht, Silke; Ludwigs, Jan-Dieter

2018-04-25

An assessment of potential risks of pesticides on wildlife is required during the process of product registration within Europe because of the importance of agricultural landscapes as wildlife habitats. Despite their peculiarity and their specific role as artificial wetlands, rice paddies are to date pooled with cereals in guidance documents on how to conduct risk assessments for birds and mammals in Europe. Hence, the focal species currently considered in risk assessments for rice paddies are those known from cereal fields and can therefore be expected to differ significantly from the species actually occurring in the wet environments of rice paddies. We present results of a comprehensive review on bird and mammal species regularly occurring in rice paddies during a time of potential pesticide exposure to identify appropriate focal species candidates for ecotoxicological pesticide risk assessment according to the European Food Safety Authority (EFSA). In addition, we present data on rice cultivation areas and agricultural practices in Europe to give background information supporting the species selection process. Our literature search identified a general scarcity of relevant data, particularly for mammals, which highlights the need for crop-specific focal species studies. However, our results clearly indicate that the relevant bird and mammal species in rice fields indeed differ strongly from the focal species used for the cereal risk assessment. They can thus be used as a baseline for more realistic wildlife risk assessments specific to rice and the development of a revised guidance document to bridge the gap for regulatory decision makers. Integr Environ Assess Manag 2018;00:000-000. © 2018 SETAC. © 2018 SETAC.

Phylogenetically Distinct Phylotypes Modulate Nitrification in a Paddy Soil

PubMed Central

Zhao, Jun; Wang, Baozhan

2015-01-01

Paddy fields represent a unique ecosystem in which regular flooding occurs, allowing for rice cultivation. However, the taxonomic identity of the microbial functional guilds that catalyze soil nitrification remains poorly understood. In this study, we provide molecular evidence for distinctly different phylotypes of nitrifying communities in a neutral paddy soil using high-throughput pyrosequencing and DNA-based stable isotope probing (SIP). Following urea addition, the levels of soil nitrate increased significantly, accompanied by an increase in the abundance of the bacterial and archaeal amoA gene in microcosms subjected to SIP (SIP microcosms) during a 56-day incubation period. High-throughput fingerprints of the total 16S rRNA genes in SIP microcosms indicated that nitrification activity positively correlated with the abundance of Nitrosospira-like ammonia-oxidizing bacteria (AOB), soil group 1.1b-like ammonia-oxidizing archaea (AOA), and Nitrospira-like nitrite-oxidizing bacteria (NOB). Pyrosequencing of 13C-labeled DNA further revealed that 13CO2 was assimilated by these functional groups to a much greater extent than by marine group 1.1a-associated AOA and Nitrobacter-like NOB. Phylogenetic analysis demonstrated that active AOB communities were closely affiliated with Nitrosospira sp. strain L115 and the Nitrosospira multiformis lineage and that the 13C-labeled AOA were related to phylogenetically distinct groups, including the moderately thermophilic “Candidatus Nitrososphaera gargensis,” uncultured fosmid 29i4, and acidophilic “Candidatus Nitrosotalea devanaterra” lineages. These results suggest that a wide variety of microorganisms were involved in soil nitrification, implying physiological diversification of soil nitrifying communities that are constantly exposed to environmental fluctuations in paddy fields. PMID:25724959

[Estimation of N loss loading by runoff from paddy field during submersed period in Hangjiahu area].

PubMed

Tian, Ping; Chen, Yingxu; Tian, Guangming; Liang, Xinqiang; Zhang, Qiuling; Yu, Qiaogang; Li, Hua

2006-10-01

As the largest bread basket in Zhejiang Province, Hangjiahu area is facing more and more serious water pollution, while the N loss loading by runoff from the paddy field during its submersed period is the main cause of the pollution. Through field experiment and fixed spot observation, the model of precipitation - runoff in Yangtze delta was testified, and the results showed that the precipitation - runoff model from HE Baogen was basically accorded with the fact after considering the impact of field overflow mouth, and the error was between - 19. 9% and + 18. 0%. The model of N concentration with precipitation - runoff in paddy field during submersed period was brought forward, with the R value being 0. 948. These two models consisted of the model of N loss loading by runoff from paddy field during submersed period. Based on this model as well as the past 30 years data of fertilization and precipitation, 1: 250,000 topography map, land use map, and water system map, the N loss loading and its distribution were estimated by using GIS method, and the results showed that the N loss loading was different from place to place, with an average of 35.26 kg N x hm(-2), and accounting for 12. 69% of the applied N. The N loss loading in Anji and Yuhang with obviously more precipitation was higher than that in other places, while Haining also had a serious N loss problem because of the huge amount of applied N.

Exploring a suitable nitrogen fertilizer rate to reduce greenhouse gas emissions and ensure rice yields in paddy fields.

PubMed

Zhong, Yiming; Wang, Xiaopeng; Yang, Jingping; Zhao, Xing; Ye, Xinyi

2016-09-15

The application rate of nitrogen fertilizer was believed to dramatically influence greenhouse gas (GHG) emissions from paddy fields. Thus, providing a suitable nitrogen fertilization rate to ensure rice yields, reducing GHG emissions and exploring emission behavior are important issues for field management. In this paper, a two year experiment with six rates (0, 75, 150, 225, 300, 375kgN/ha) of nitrogen fertilizer application was designed to examine GHG emissions by measuring carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) flux and their cumulative global warming potential (GWP) from paddy fields in Hangzhou, Zhejiang in 2013 and 2014. The results indicated that the GWP and rice yields increased with an increasing application rate of nitrogen fertilizer. Emission peaks of CH4 mainly appeared at the vegetative phase, and emission peaks of CO2, and N2O mainly appeared at reproductive phase of rice growth. The CO2 flux was significantly correlated with soil temperature, while the CH4 flux was influenced by logging water remaining period and N2O flux was significantly associated with nitrogen application rates. This study showed that 225kgN/ha was a suitable nitrogen fertilizer rate to minimize GHG emissions with low yield-scaled emissions of 3.69 (in 2013) and 2.23 (in 2014) kg CO2-eq/kg rice yield as well as to ensure rice yields remained at a relatively high level of 8.89t/ha in paddy fields. Copyright © 2016 Elsevier B.V. All rights reserved.

Detection of Giardia in environmental waters by immuno-PCR amplification methods.

PubMed

Mahbubani, M H; Schaefer, F W; Jones, D D; Bej, A K

1998-02-01

Genomic DNA was extracted either directly from Giardia muris cysts seeded into environmental surface waters or from cysts isolated by immunomagnetic beads (IMB). A 0.171-kbp segment of the giardin gene was PCR-amplified following "direct extraction" of Giardia DNA from seeded Cahaba river water concentrate with moderate turbidity (780 JTU's), but DNA purified from seeded Colorado river water concentrates with high turbidity (2 x 10(5) JTUs) failed to amplify. However, if the cysts were first separated by the IMB approach from seeded Cahaba or Colorado river waters, and the DNA released by a freeze-boil Chelex(R)100 treatment, detection of G. muris by PCR amplification could be achieved at a sensitivity of 3 x 10(0) or 3 x 10(1) cysts/ml, respectively. If, however, the G. muris cysts used to seed even moderately turbid river waters (780 JTUs) were formalin treated (which is conventionally used for microscopic examination), neither direct extraction nor IMB purification methods yielded amplifiable DNA. Use of immunomagnetic beads to separate Giardia cysts from complex matrices of environmental surface waters followed by DNA release and PCR amplification of the target giardin gene improved the reliability of detection of this pathogen with the required sensitivity.

Planting and care of fine hardwood seedlings: Nursery production of hardwood seedlings

Treesearch

Douglass F. Jacobs

2003-01-01

Access to quality tree seedlings is an essential component of a successful hardwood reforestation project. Hardwood plantations may be established by sowing seed directly to a field site, but the success of direct seeding operations has been inconsistent for many species, which indicates that more research is needed before this practice can be recommended. For...

Factors affecting the establishment of direct-seeded pine on surface-mine spoils

Treesearch

William T. Plass

1974-01-01

In a greenhouse study the emergence, survival, and growth of seven species of pine were related to chemical and textural characteristics of 12 Kentucky spoils. The results identify three factors that may affect the establishment of direct-seeded pine on surface-mine spoils. First, fine-textured spoil material may restrict seedling emergence. Coarse-textured sandstones...

Modeling the size-density relationship in direct-seeded slash pine stands

Treesearch

Quang V. Cao; Thomas J. Dean; V. Clark Baldwin

2000-01-01

The relationship between quadratic mean diameter and tree density appeared curvilinear on a log–log scale, based on data from direct-seeded slash pine (Pinus elliotti var. elliotti Engelm.) stands. The self-thinning trajectory followed a straight line for high tree density levels and then turned away from this line as tree density...

Direct Seeding Scarlet Oak in the North Carolina Mountains

Treesearch

Earl R. Sluder

1965-01-01

Seedling establishment rates varied from 0 to 50 percent in a direct seeding study with scarlet oak (Quercus coccinea Muenchh.) on the Bent Creek Experimental Forest near Asheville, North Carolina. Acorns planted 2 inches deep in the spring with screen protection produced the most seedlings; those surface sown without screens in the spring or fall...

Immobilization of indigenous holocellulase on iron oxide (Fe2O3) nanoparticles enhanced hydrolysis of alkali pretreated paddy straw.

PubMed

Kumar, Ajay; Singh, Surender; Tiwari, Rameshwar; Goel, Renu; Nain, Lata

2017-03-01

The holocellulase from Aspergillus niger SH3 was characterized and found to contain 125 proteins including cellulases (26), hemicellulases (21), chitinases (10), esterases (6), amylases (4) and hypothetical protein (32). The crude enzyme was immobilized on five different nanoparticles (NPs) via physical adsorption and covalent coupling methods. The enzyme-nanoparticle complexes (ENC) were screened for protein binding, enzymatic activities and immobilization efficiency. Magnetic enzyme-nanoparticle complexes (MENC) showed higher immobilization efficiency (60-80%) for most of the enzymes. MENC also showed better catalytic efficiencies in term of higher V max and lower K m than free enzyme. Saccharification yields from alkali treated paddy straw were higher (375.39mg/gds) for covalently immobilized MENC than free enzyme (339.99mg/gds). The immobilized enzyme was used for two cycles of saccharification with 55% enzyme recovery. Hence, this study for the first time demonstrated the immobilization of indigenous enzyme and its utilization for saccharification of paddy straw. Copyright © 2016 Elsevier B.V. All rights reserved.

The Growth Periods Responses of Double-season Paddy Rice to Climate Change in Hunan Province, China over the Past Two Decades

NASA Astrophysics Data System (ADS)

Wang, Y.; Li, Y.; Yi, M.; Ye, T.

2015-12-01

The shifts of timing and length of the growing season (TLGS) are important indicators of crop response to climate change. With the help of satellite image data, it becomes feasible to retrieve the TLGS in a spatially continuous manner, which also accommodates local variation of TGSs. In this article, the TGSs of paddy rice in Hunan Province, China since 1995 was retrieved using times-series curves of MODIS Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and Land Surface Water Index (LSWI). The change in TLGS and its connection to regional climate change was discussed. The results showed the advance of TGSs of double-season paddy rice and the reduction of GSL in the past 20 years, which is believed to be linked to the rise in the temperature and precipitation in the growth periods. Understanding the local variation and trend of TLGS influenced by climate change is essential for making agricultural adaptive policies to reduce the risk of crop damaged, also can provide key information for studying how multi-hazards affect crop exposure.

Characteristics of Nitrogen and Phosphorus Effluent Load from a Paddy-field District Implementing Crop Rotation

NASA Astrophysics Data System (ADS)

Hama, Takehide; Aoki, Takeru; Osuga, Katsuyuki; Nakamura, Kimihito; Sugiyama, Sho; Kawashima, Shigeto

Implementation of collective crop rotation in a paddy-field district may increase nutrients effluent load. We have investigated a paddy-field district implementing collective crop rotation of wheat and soybeans, measured temporal variations in nutrients concentration of drainage water and the amount of discharged water for consecutive three years, and estimated nutrients effluent load from the district during the irrigation and non-irrigation periods. As a result, the highest concentration of nutrients was observed during the non-irrigation period in every investigation year. It was shown that high nutrients concentration of drainage water during the non-irrigation period was caused by runoff of fertilizer applied to wheat because the peaks of nutrients concentration of drainage water were seen in rainy days after fertilizer application in the crop-rotation field. The effluent load during the non-irrigation periods was 16.9-22.1 kgN ha-1 (nitrogen) and 0.84-1.42 kgP ha-1 (phosphorus), which respectively accounted for 46-66% and 27-54% of annual nutrients effluent load.

Development of natural cellulase inhibitor mediated intensified biological pretreatment technology using Pleurotus florida for maximum recovery of cellulose from paddy straw under solid state condition.

PubMed

Naresh Kumar, Manickam; Ravikumar, Rajarathinam; Thenmozhi, Senniyappan; Kirupa Sankar, Muthuvelu

2017-11-01

Inhibitor mediated intensified bio-pretreatment (IMBP) technology using natural cellulase inhibitor (NCI) for maximum cellulose recovery from paddy straw was studied. Pretreatment was carried out under solid state condition. Supplementation of 8% NCI in pretreatment medium improves cellulose recovery and delignification by 1.2 and 1.5-fold respectively, compared to conventional bio-pretreatment due to inhibition of 61% of cellulase activity in IMBP. Further increase in NCI concentration showed negative effect on Pleurotus florida growth and suppress the laccase productivity by 1.1-fold. Laccase activity in IMBP was found to be 2.0U/mL on 19 th day, which is higher than (1.5U/mL) conventional bio-pretreatment. Physico-chemical modifications in paddy straw before and after pretreatment were analysed by SEM, ATR-FTIR, XRD and TGA. According to these findings, the IMBP technology can be a viable eco-friendly technology for sustainable production of bioethanol with maximum cellulose recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Relationship of starch changes to puffing expansion of parboiled rice.

PubMed

Mahanta, Charu Lata; Bhattacharya, K R

2010-03-01

'Intan' variety of paddy (Oryza sativa) was tested for puffing. It was parboiled under a wide range of paddy moisture content, steaming pressure and time, as also temperature and time of sand heating. The resulting milled rices were studied for their diverse properties including puffing. Indices of starch changes in the samples were calculated as: (1) gelatinisation index from the solubility of amylose in 0.2 N KOH; (2) amylopectin retrogradation from the post-production drop in room-temperature hydration power of the parboiled paddy during air-drying, (3) thermal breakdown of starch from the drop in gel permeation chromatographic fraction I of starch; lipid-amylose complexation indirectly from (4) drop in rate of water uptake during cooking and (5) cooked-rice firmness. It was found that the puffing expansion was very highly correlated with the combined above 5 indices of starch changes, as much as 90% of the variation in puffing being explainable on that basis. Puffing was promoted by gelatinisation as well as lipid-amylose complexation, but was retarded by amylopectin retrogradation and probably starch breakdown.

Econometric Model of Rice Policy Based On Presidential Instruction

NASA Astrophysics Data System (ADS)

Abadi Sembiring, Surya; Hutauruk, Julia

2018-01-01

The objective of research is to build an econometric model based on Presidential Instruction rice policy. The data was monthly time series from March 2005 to September 2009. Rice policy model specification using simultaneous equation, consisting of 14 structural equations and four identity equation, which was estimated using Two Stages Least Squares (2SLS) method. The results show that: (1) an increase of government purchasing price of dried harvest paddy has a positive impact on to increase in total rice production and community rice stock, (2) an increase community rice stock lead to decrease the rice imports, (3) an increase of the realization of the distribution of subsidized ZA fertilizers and the realization of the distribution of subsidized NPK fertilizers has a positive impact on to increase in total rice production and community rice stock and to reduce rice imports, (4) the price of the dried harvest paddy is highly responsive to the water content of dried harvest paddy both the short run and long run, (5) the quantity of rice imported is highly responsive to the imported rice price, both short run and long run.

The influence of land use on the concentration and vertical distribution of PBDEs in soils of an e-waste recycling region of South China.

PubMed

Cheng, Zhineng; Wang, Yan; Wang, Shaorui; Luo, Chunling; Li, Jun; Chaemfa, Chakra; Jiang, Haoyu; Zhang, Gan

2014-08-01

The vertical distribution of polybrominated diphenyl ethers (PBDEs) in soil at four sites within an e-waste recycling region of South China was investigated. PBDE concentrations in soil ranged from 1.38 to 765 ng/g. There was a trend of decreasing PBDE concentration with soil depth, especially in the paddy field. However, high concentrations of BDE-209 were found in deeper soils indicating a highly preferential migration. There was a stronger correlation between PBDEs and total organic carbon (TOC), compared to dissolved organic carbon (DOC), which suggests that the association between non-dissolved organic carbon (NDOC) and PBDEs is stronger than for DOC. Different land use types, in particular differences in farming activities, significantly influenced the vertical distribution of PBDEs in soils. PBDEs displayed a higher leaching tendency in moist paddy soil than in drier soils. The frequent flooding condition in paddy field may facilitate the vertical transfer of PBDEs to the deeper soils. Copyright © 2014 Elsevier Ltd. All rights reserved.

Forms of trace arsenic, cesium, cadmium, and lead transported into river water for the irrigation of Japanese paddy rice fields

NASA Astrophysics Data System (ADS)

Nakaya, Shinji; Chi, Hai; Muroda, Kengo; Masuda, Harue

2018-06-01

In this study, we focus on the behavior of geogenic, toxic trace elements, particularly As, Cs, Cd, and Pb, during their transportation in two rivers for irrigation commonly used in monsoon Asia; one river originates from an active volcano, Mt. Asama, and the other originates from a currently inactive volcano, Yatsugatake Mountains in Nagano, Japan. These rivers were investigated to understand the role of river water as a pollutant of rice and other aquatic plants (via irrigation) and aquatic animals. The results indicated that the behavior of toxic trace elements in river water are likely controlled by their interactions with particulate Fe, Al, and Ti compounds. The majority of Pb and Cd is transported as particulate matter with Fe, Al, and Ti, while the majority of As is transported in the dissolved form, predominantly as arsenate, with low abundance of particulate matter. Cs is transported either as the dissolved form or as particulate matter in both rivers. The investigated elements are transported in the rivers as particulate and dissolved forms, and the ratio of these forms is controlled by the pH and presence of particulate Fe, Al, and Ti phases in the river water. With respect to Cs in both rivers, the parameter governing the concentration and transportation of Cs, in the bimodal form (i.e., particulate and dissolved forms), through the river possibly shifts from sorption to pH by particulate Fe-Al-Ti, according to the abrupt increase in the concentration of Cs in the river. The chemical attraction of particulate Fe-Al-Ti for Cs is weaker than that for Pb and Cd, indicating that the lower electronegativity of Cs weakens the chemical attraction on a colloid for the competitive sorption with the other trace elements. The different relationships between As and Fe in the river and in the irrigation water and soil water, as well as those in paddy rice, suggested that As in paddy rice is not directly derived from As in the irrigation water from the river under flooding.

Seeding and planting upland oaks

Treesearch

1989-01-01

Oaks can be planted or seeded in uplands to: (1) afforest old fields, strip-mined areas, or other areas devoid of trees, and (2) supplement natural reproduction within existing forests. Planting is usually more successful than direct seeding. But even under good conditions survival and growth of planted oak has been considerably poorer than with conifers and other...

Substrate With Low Secondary Emissions

NASA Technical Reports Server (NTRS)

Jensen, Kenneth A. (Inventor); Curren, Arthur N. (Inventor); Roman, Robert F. (Inventor)

2000-01-01

The present invention is directed to a method and apparatus for producing a highly -textured surface on a copper substrate -with only extremely small amounts of texture-inducing seeding or masking material. The texture-inducing seeding material is delivered to the copper substrate electrically switching the seeding material in and out of a circuit loop.

Billet-planted sugarcane responds positively to chemical seed treatments

USDA-ARS?s Scientific Manuscript database

Louisiana’s 2015 sugarcane crop was worth over $750 million and generated $2 billion in direct economic impact to the state. One of the biggest variable expenses was planting. Seed cane is costly to grow because it occupies land that could produce cane destined for a mill. Whole stalk seeding rates ...

Fabrication of silicon films from patterned protruded seeds

NASA Astrophysics Data System (ADS)

Zeng, Huang; Zhang, Wei; Li, Jizhou; Wang, Cong; Yang, Hui; Chen, Yigang; Chen, Xiaoyuan; Liu, Dongfang

2017-05-01

Thin, flexible silicon crystals are starting up applications such as light-weighted flexible solar cells, SOI, flexible IC chips, 3D ICs imagers and 3D CMOS imagers on the demand of high performance with low cost. Kerfless wafering technology by direct conversion of source gases into mono-crystalline wafers on reusable substrates is highly cost-effective and feedstock-effective route to cheap wafers with the thickness down to several microns. Here we show a prototype for direct conversion of silicon source gases to wafers by using the substrate with protruded seeds. A reliable and controllable method of wafer-scaled preparation of protruded seed patterns has been developed by filling liquid wax into a rod array as the mask for the selective removal of oxide layer on the rod head. Selectively epitaxial growth is performed on the protruded seeds, and the voidless film is formed by the merging of neighboring seeds through growing. And structured hollows are formed between the grown film and the substrate, which would offer the transferability of the grown film and the reusability of the protruded seeds.

Glucosinolate pattern in Isatis tinctoria and I. indigotica seeds.

PubMed

Mohn, Tobias; Hamburger, Matthias

2008-06-01

The glucosinolate patterns in seeds of five ISATIS TINCTORIA and two ISATIS INDIGOTICA accessions were assessed with a recently developed and validated LC-MS assay for direct analysis of glucosinolates without prior desulfatation. Glucosinolate peaks were identified with in-source fragmentation and detection of the sulfate anion ( M/Z = 97), and by MS/MS experiments. The glucosinolate patterns of the seeds showed characteristic differences compared to leaves. Glucoisatisin and epiglucoisatisin were diagnostic of seed samples. Qualitative and quantitative differences in glucosinolate patterns between both ISATIS species were found for seed samples, enabling a differentiation of the two medicinal plants at the level of seed material.

In Vivo Non-Destructive Monitoring of Capsicum Annuum Seed Growth with Diverse NaCl Concentrations Using Optical Detection Technique.

PubMed

Ravichandran, Naresh Kumar; Wijesinghe, Ruchire Eranga; Lee, Seung-Yeol; Shirazi, Muhammad Faizan; Jung, Hee-Young; Jeon, Mansik; Kim, Jeehyun

2017-12-12

We demonstrate that optical coherence tomography (OCT) is a plausible optical tool for in vivo detection of plant seeds and its morphological changes during growth. To investigate the direct impact of salt stress on seed germination, the experiment was conducted using Capsicum annuum seeds that were treated with different molar concentrations of NaCl. To determine the optimal concentration for the seed growth, the seeds were monitored for nine consecutive days. In vivo two-dimensional OCT images of the treated seeds were obtained and compared with the images of seeds that were grown using sterile distilled water. The obtained results confirm the feasibility of using OCT for the proposed application. Normalized depth profile analysis was utilized to support the conclusions.