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Sample records for rainfed lowland rice

  1. Yield Loss Caused by Meloidogyne graminicola on Lowland Rainfed Rice in Bangladesh.

    PubMed

    Padgham, J L; Duxbury, J M; Mazid, A M; Abawi, G S; Hossain, M

    2004-03-01

    The impact of Meloidogyne graminicola on growth and yield of lowland rainfed rice was assessed with and without carbofuran in a rice-wheat rotation area of northwestern Bangladesh. The experiment was conducted on farmer fields and at a research station, with experimental plots arranged in a randomized complete block design. Prior to transplanting, rice seedling height and dry weight were greater (P rice yield increased by 1.0 t/ha where carbofuran was applied to the seedbed and field-both at the research station (P lowland rainfed rice in production fields in Bangladesh. PMID:19262786

  2. Yield Loss Caused by Meloidogyne graminicola on Lowland Rainfed Rice in Bangladesh

    PubMed Central

    Padgham, J. L.; Duxbury, J. M.; Mazid, A. M.; Abawi, G. S.; Hossain, M.

    2004-01-01

    The impact of Meloidogyne graminicola on growth and yield of lowland rainfed rice was assessed with and without carbofuran in a rice-wheat rotation area of northwestern Bangladesh. The experiment was conducted on farmer fields and at a research station, with experimental plots arranged in a randomized complete block design. Prior to transplanting, rice seedling height and dry weight were greater (P ≤ 0.05) and soil levels of M. graminicola were lower (P ≤ 0.05) in the treated seedbed plots compared to the nontreated control plots. Nematicide application to the field at transplanting had a greater effect (P ≤ 0.05) on mid-season plant growth than did nematicide application to the seedbed at sowing, and rice yield increased by 1.0 t/ha where carbofuran was applied to the seedbed and field-both at the research station (P ≤ 0.05) and on farmer fields (P ≤ 0.10)- compared to a nontreated control. This is the first report of a negative impact of M. graminicola on growth and yield of lowland rainfed rice in production fields in Bangladesh. PMID:19262786

  3. The effects of water regime on phosphorus responses of rainfed lowland rice cultivars

    PubMed Central

    Huguenin-Elie, O.; Kirk, G. J. D.; Frossard, E.

    2009-01-01

    Background and Aims Soil phosphorus (P) solubility declines sharply when a flooded soil drains, and an important component of rice (Oryza sativa) adaptation to rainfed lowland environments is the ability to absorb and utilize P under such conditions. The aim of this study was to test the hypothesis that rice cultivars differ in their P responses between water regimes because P uptake mechanisms differ. Methods Six lowland rice cultivars (three considered tolerant of low P soils, three sensitive) were grown in a factorial experiment with three water regimes (flooded, moist and flooded-then-moist) and four soil P levels, and growth and P uptake were measured. Small volumes of soil were used to maximize inter-root competition and uptake per unit root surface. The results were compared with the predictions of a model allowing for the effects of water regime on P solubility and diffusion. Key Results The plants were P stressed but not water stressed in all the water regimes at all P levels except the higher P additions in the flooded soil. The cultivar rankings scarcely differed between the water regimes and P additions. In all the treatments, the soil P concentrations required to explain the measured uptake were several times the concentration of freely available P in the soil. Conclusions The cultivar rankings were driven more by differences in growth habit than specific P uptake mechanisms, so the hypothesis cannot be corroborated with these data. Evidently all the plants could tap sparingly soluble forms of P by releasing a solubilizing agent or producing a greater root length than measured, or both. However, any cultivar differences in this were not apparent in greater net P uptake, possibly because the restricted rooting volume meant that additional P uptake could not be converted into new root growth to explore new soil volumes. PMID:18945744

  4. Tracing the allocation of water in rainfed rice ecosystem by partitioning evapotranspiration of rainfed rice (Oryza Sativa L.)

    NASA Astrophysics Data System (ADS)

    Nay-Htoon, Bhone; Dubbert, Maren; Wei, Xue; Cuntz, Matthias; Ko, Jonghan; Tenhunen, John; Werner, Christiane

    2015-04-01

    To understand productive and unproductive water use of crop production, partitioning evapotranspiration (ET ) into evaporation (E) and transpiration (T ) is important. Water movements within the eco-hydrologic cycle of agroecosystems can be traced by stable oxygen isotopes of water (δ18O) and plant transpiration and soil evaporation can also be estimated by tracing the δ18O. We quantified the contribution of transpiration to total ecosystem evapotranspiration of rainfed rice field by a stable oxygen isotope approach and FAO 56 dual crop modelling approach. Our study aims to provide quantification of ecosystem water cycle of rainfed rice by partitioning productive and unproductive water use since productivity and water use of rice which is a highly water demanding agroecosystem, is under intense research. Crop season total evapotranspiration fluxes from rainfed rice was mainly dominated by transpiration (T to ET contribution (T /ET ) = 65%) and domination of transpiration over evaporation fluxes was noted since early vegetative stage (Leaf Area Index = 0.8 m2 m-2) until harvesting. T /ET of rainfed rice fluctuated with changes in soil water content (SWC) and the highest T /ET was found at SWC of 0.34 m3 m-3, during seedling stage. Our results demonstrate that partitioning ET by FAO 56 dual crop model is in a good agreement with δ18O isotope based ET partitioning results. Using monthly mean values of leaf resistance and vegetation index derived crop coefficients instead of original fixed parameters of the FAO 56 dual crop model resulted better agreement with δ18O isotope based ET partitioning.

  5. Nitrogen fixation by photosynthetic bacteria in lowland rice culture.

    PubMed

    Habte, M; Alexander, M

    1980-02-01

    Propanil (3',4'-dichloropropionanilide) was a potent inhibitor of the nitrogenase activity of blue-green algae (cyanobacteria) in flooded soil, but the herbicide at comparable concentrations was not toxic to rice, protozoa, and nitrogen-fixing bacteria. Ethanol-amended flooded soils treated with propanil exhibited higher rates of nitrogenase activity than those not treated with the herbicide. The enhanced nitrogenase activity in propanil-treated soils was associated with a rise in the population of purple sulfur bacteria, especially of cells resembling Chromatium and Thiospirillum. By employing propanil and a means of excluding light from the floodwater to prevent the development of phototrophs during rice growth under lowland conditions, the relative activities of blue-green algae, photosynthetic bacteria, and the rhizosphere microflora were determined. The results suggest that the potential contribution of photosynthetic bacteria may be quite high. PMID:16345507

  6. Nitrogen Fixation by Photosynthetic Bacteria in Lowland Rice Culture

    PubMed Central

    Habte, M.; Alexander, M.

    1980-01-01

    Propanil (3′,4′-dichloropropionanilide) was a potent inhibitor of the nitrogenase activity of blue-green algae (cyanobacteria) in flooded soil, but the herbicide at comparable concentrations was not toxic to rice, protozoa, and nitrogen-fixing bacteria. Ethanol-amended flooded soils treated with propanil exhibited higher rates of nitrogenase activity than those not treated with the herbicide. The enhanced nitrogenase activity in propanil-treated soils was associated with a rise in the population of purple sulfur bacteria, especially of cells resembling Chromatium and Thiospirillum. By employing propanil and a means of excluding light from the floodwater to prevent the development of phototrophs during rice growth under lowland conditions, the relative activities of blue-green algae, photosynthetic bacteria, and the rhizosphere microflora were determined. The results suggest that the potential contribution of photosynthetic bacteria may be quite high. PMID:16345507

  7. Different maternal origins of Japanese lowland and upland rice populations.

    PubMed

    Ishikawa, R.; Sato, -I.; Tang, T.; Nakamura, I.

    2002-05-01

    Plastid subtype ID (PS-ID) sequences were determined from sequence data based on CA repeats between genes rpl16 and rpl14 in Japanese lowland and upland cultivars. The PS-ID sequences of Japanese rice cultivars showed that there are different maternal origins between lowland and upland cultivars. One subtype, 6C7A, of PS-ID sequences was predominant in all but one Japanese lowland cultivar and carried a combination of the indica-specific subtype 8C8A and japonica-specific nuclear markers for the isozyme genotype. It is probably a nuclear-cytoplasmic recombinant resulting from natural out-crossing and succeeding self-pollination. The origin of the plastid was re-confirmed by the existence of an indica-specific deletion in the plastid genome. In contrast, the Japanese upland cultivars showed two subtypes, 7C6A and 6C7A, of PS-ID sequences. An upland-specific isozyme allele as a nuclear marker was equally predominant in cultivars carrying each subtype. The existence of these particular upland-specific nuclear and cytoplasmic genotypes suggests that the origin of Japanese upland cultivars is different from that of Japanese lowland cultivars. Cultivars carrying the upland-specific nuclear genotype are common in Southeast Asia, but the combination of the upland-specific nuclear and cytoplasmic genotypes which is the same as the Japanese upland predominant type was found in cultivars only in Taiwan and Indonesia. Japanese upland cultivars are closely related to those cultivars. PMID:12582602

  8. 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

  9. Traits and QTLs for development of dry direct-seeded rainfed rice varieties.

    PubMed

    Sandhu, Nitika; Torres, Rolando O; Sta Cruz, Ma Teresa; Maturan, Paul Cornelio; Jain, Rajinder; Kumar, Arvind; Henry, Amelia

    2015-01-01

    The development of rice varieties for dry direct-seeded conditions can be accelerated by selecting suitable traits. In the present investigation, traits hypothesized to be important for direct-seeded conditions in rainfed systems, including seedling emergence, early vegetative vigour, nutrient uptake, nodal root number, and root hair length and density, were characterized to study the genetic control of these traits and their relationship with grain yield under seedling- and reproductive-stage drought stress. Two BC₂F₄ mapping populations derived from crosses of Aus276, a drought-tolerant aus variety, with MTU1010 and IR64, high-yielding indica mega-varieties, were developed and studied to identify quantitative trait loci (QTLs) that showed large and consistent effects. A total of 26 QTLs associated with 23 traits and 20 QTLs associated with 13 traits were mapped in the Aus276/3*IR64 and Aus276/3*MTU1010 populations, respectively. qGY₆.₁, qGY₁₀.₁, qGY₁.₁, and qEVV₉.₁ were found to be effective in both populations under a wide range of conditions. QTLs for several seedling-stage traits co-located with QTLs for grain yield, including early vegetative vigour and root hair length. On chromosome 5, several QTLs for nutrient uptake co-located with QTLs for root hair density and nematode gall rating. Six lines were selected from both populations based on grain yield and the presence of QTLs, and these lines typically showed improved seedling-stage traits (nodal root number, dry shoot weight, and root hair length and density). The co-located QTLs identified here can be used in research aimed at increasing the yield and adaptability of rainfed rice to direct-seeded conditions. PMID:25336682

  10. Traits and QTLs for development of dry direct-seeded rainfed rice varieties

    PubMed Central

    Sandhu, Nitika; Torres, Rolando O.; Sta Cruz, Ma. Teresa; Maturan, Paul Cornelio; Jain, Rajinder; Kumar, Arvind; Henry, Amelia

    2015-01-01

    The development of rice varieties for dry direct-seeded conditions can be accelerated by selecting suitable traits. In the present investigation, traits hypothesized to be important for direct-seeded conditions in rainfed systems, including seedling emergence, early vegetative vigour, nutrient uptake, nodal root number, and root hair length and density, were characterized to study the genetic control of these traits and their relationship with grain yield under seedling- and reproductive-stage drought stress. Two BC2F4 mapping populations derived from crosses of Aus276, a drought-tolerant aus variety, with MTU1010 and IR64, high-yielding indica mega-varieties, were developed and studied to identify quantitative trait loci (QTLs) that showed large and consistent effects. A total of 26 QTLs associated with 23 traits and 20 QTLs associated with 13 traits were mapped in the Aus276/3*IR64 and Aus276/3*MTU1010 populations, respectively. qGY6.1, qGY10.1, qGY1.1, and qEVV9.1 were found to be effective in both populations under a wide range of conditions. QTLs for several seedling-stage traits co-located with QTLs for grain yield, including early vegetative vigour and root hair length. On chromosome 5, several QTLs for nutrient uptake co-located with QTLs for root hair density and nematode gall rating. Six lines were selected from both populations based on grain yield and the presence of QTLs, and these lines typically showed improved seedling-stage traits (nodal root number, dry shoot weight, and root hair length and density). The co-located QTLs identified here can be used in research aimed at increasing the yield and adaptability of rainfed rice to direct-seeded conditions. PMID:25336682

  11. Human energy expenditure in lowland rice cultivation in Malaysia.

    PubMed

    Nawi, N M; Yahya, A; Chen, G; Bockari-Gevao, S M; Maraseni, T N

    2012-01-01

    A study was undertaken to evaluate the human energy consumption of various field operations involved in lowland rice cultivation in Malaysia. Based on recorded average heart rates, fertilizing was found to be the most strenuous operation, with an average heart rate of 138 beats min(-1). There were no significant differences in the average heart rates of the subjects among the individual tasks within the first plowing, second plowing, and harvesting operations, with the average heart rates for these three tasks being 116, 106, and 106 beats min(-1), respectively. The corresponding energy expenditures were 3.90, 3.43, and 3.35 kcal min(-1). Loading the seed into the blower tank and broadcasting the seed were the most critical tasks for the seed broadcasting operation, with average heart rates of 124 and 136 beats min(-1), respectively. The highest energy expenditure of 418.38 kcal ha(-1) was observed for seed broadcasting, and the lowest energy expenditure of 127.96 kcal ha(-1) was for second plowing. The total seasonal human energy expenditure for rice cultivation was estimated to be 5810.71 kcal ha(-1), 55.7% of which was spent on pesticide spraying. Although the sample size in this study was relatively small, the results indicated that human energy expenditure per unit area (kcal ha(-1)) was positively linked to the average heart rate of the subjects and negatively linked to the field capacity. Thus, mechanization of certain tasks could decrease worker physical effort and fatigue and increase production. PMID:22458015

  12. Identification and characterization of large-effect quantitative trait loci for grain yield under lowland drought stress in rice using bulk-segregant analysis.

    PubMed

    Venuprasad, Ramaiah; Dalid, C O; Del Valle, M; Zhao, D; Espiritu, M; Sta Cruz, M T; Amante, M; Kumar, A; Atlin, G N

    2009-12-01

    An F(4:5) population of 490 recombinant inbred lines (RILs) from the cross Apo/(2*)Swarna was used to detect quantitative trait loci (QTL) with large effects on grain yield under drought stress using bulk-segregant analysis (BSA). Swarna is an important rainfed lowland rice variety grown on millions of hectares in Asia, but is highly susceptible to drought and aerobic soil conditions. Apo is an aerobic-adapted variety with moderate tolerance to drought. Two rice microsatellite (RM) markers, RM324, and RM416, located on chromosomes 2 and 3, respectively, were shown via BSA to be strongly associated with yield under lowland drought stress. The effects of these QTL were tested in a total of eight hydrological environments over a period of 3 years. The QTL linked to RM416 (DTY(3.1)) had a large effect on grain yield under severe lowland drought stress, explaining about 31% of genetic variance for the trait (P < 0.0001). It also explained considerable variance for yield under mild stress in lowland conditions and aerobic environments. To our knowledge this is the first reported QTL that has a large effect on yield in both lowland drought and aerobic environments. The QTL linked to RM324 (DTY(2.1)) had a highly significant effect on grain yield in lowland drought stress (R(2) = 13-16%) and in two aerobic trials. The effect of these QTL on grain yield was verified to be not mainly due to phenology differences. Effects of DTY(3.1) on yield under stress have been observed in several other rice mapping populations studied at IRRI. Results of this study indicate that BSA is an effective method of identifying QTL alleles with large effects on rice yield under severe drought stress. The Apo alleles for these large-effect QTL for grain yield under drought and aerobic conditions may be immediately exploited in marker-assisted-breeding to improve the drought tolerance of Swarna. PMID:19841886

  13. Adaptive Epigenetic Differentiation between Upland and Lowland Rice Ecotypes Revealed by Methylation-Sensitive Amplified Polymorphism

    PubMed Central

    Xiong, Jie; Tao, Tao; Zheng, Xiaoguo; Wei, Haibin; Yue, Yunxia; Chen, Liang; Luo, Lijun

    2016-01-01

    The stress-induced epimutations could be inherited over generations and play important roles in plant adaption to stressful environments. Upland rice has been domesticated in water-limited environments for thousands of years and accumulated drought-induced epimutations of DNA methylation, making it epigenetically differentiated from lowland rice. To study the epigenetic differentiation between upland and lowland rice ecotypes on their drought-resistances, the epigenetic variation was investigated in 180 rice landraces under both normal and osmotic conditions via methylation-sensitive amplified polymorphism (MSAP) technique. Great alterations (52.9~54.3% of total individual-locus combinations) of DNA methylation are recorded when rice encountering the osmotic stress. Although the general level of epigenetic differentiation was very low, considerable level of ΦST (0.134~0.187) was detected on the highly divergent epiloci (HDE). The HDE detected in normal condition tended to stay at low levels in upland rice, particularly the ones de-methylated in responses to osmotic stress. Three out of four selected HDE genes differentially expressed between upland and lowland rice under normal or stressed conditions. Moreover, once a gene at HDE was up-/down-regulated in responses to the osmotic stress, its expression under the normal condition was higher/lower in upland rice. This result suggested expressions of genes at the HDE in upland rice might be more adaptive to the osmotic stress. The epigenetic divergence and its influence on the gene expression should contribute to the higher drought-resistance in upland rice as it is domesticated in the water-limited environment. PMID:27380174

  14. A Comparative Molecular-Physiological Study of Submergence Response in Lowland and Deepwater Rice1

    PubMed Central

    Van Der Straeten, Dominique; Zhou, Zhongyi; Prinsen, Els; Van Onckelen, Harry A.; Van Montagu, Marc C.

    2001-01-01

    Survival of rice (Oryza sativa) upon an extreme rise of the water level depends on rapid stem elongation, which is mediated by ethylene. A genomic clone (OS-ACS5) encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, which catalyzes a regulatory step in ethylene biosynthesis, has been isolated from cv IR36, a lowland rice variety. Expression was induced upon short- and long-term submergence in cv IR36 and in cv Plai Ngam, a Thai deepwater rice variety. Under hypoxic conditions, abscisic acid and gibberellin had a reciprocal opposite effect on the activity of OS-ACS5. Gibberellin up-regulated and abscisic acid down-regulated OS-ACS5 mRNA accumulation. Growth experiments indicated that lowland rice responded to submergence with a burst of growth early on, but lacked the ability to sustain elongation growth. Sustained growth, characteristic for deepwater rice, was correlated with a prolonged induction of OS-ACS5. In addition, a more pronounced capacity to convert ACC to ethylene, a limited ACC conjugation, and a high level of endogenous gibberellin20 were characteristic for the deepwater variety. An elevated level of OS-ACS5 messenger was found in cv IR36 plants treated with exogenous ACC. This observation was concomitant with an increase in the capacity of converting ACC to ethylene and in elongation growth, and resulted in prolonged survival. In conclusion, OS-ACS5 is involved in the rapid elongation growth of deepwater rice by contributing to the initial and long-term increase in ethylene levels. Our data also suggest that ACC limits survival of submerged lowland rice seedlings. PMID:11161052

  15. Characterization of rice (Oryza sativa L.) genotypes on the basis of morpho-physiological and biochemical traits grown under aerobic situation in rainfed ecosystem .

    PubMed

    Kumar, Santosh; Dwivedi, Sharad Kumar; Singh, S S; Kumar, Sanjeev; Sundaram, R K; Shivani; Mall, A K

    2015-07-01

    The objective of the present study was to examine the effect of aerobic situation on yield, physiological and biochemical traits of advanced breeding lines of rice. Experiment was conducted with two set of rice genotypes under two water regimes (aerobic and irrigated), during three consecutive wet seasons 2010-2012. Significant decrease in yield was observed in rice genotypes grown under aerobic situation as compared to the irrigated ones. Promising rice genotypes having the ability to maintain high plant biomass, harvest index, early vegetative vigour, improved physiological and biochemical traits in terms of relative water content (RWC), leaf area index (LAI), total soluble sugar, starch, protien and proline content help to sustain higher grain yield under aerobic situation. The yield gap between aerobic and irrigated rice ranged between 24% to 68%. Grain yield showed positive correlation with harvest index (0.434), test weight (0.647), plant biomass (0.411) and effective tiller numbers (0.473), whereas spikelet sterility was negative associated (-0.380). The current study suggested that promising genotypes viz., IR77298-14-1-2-130-2, IR84899-B-182-3-1-1-2, IR84887-B-157-38-1-1-3 and IR 84899-B-179-1-1-1-2 for aerobic situation, showing yield advantage due to better performance of physiological and biochemical traits, might be adopted in large area of rainfed ecosystem as well as in irrigated areas where water scarcity was a major problem. PMID:26364481

  16. Economics of Rainfed Cropping Systems: Northeast Thailand

    NASA Astrophysics Data System (ADS)

    Johnson, Sam H., III; Charoenwatana, Terd

    1981-06-01

    Using a computer model to simulate effective rainfall, it is shown that a flexible rainfed cropping system based on a legume crop planted before rice has a greater expected return than present subsistent rainfed cropping systems. Combining a legume crop intercropped with cassava or kenaf further increases the expected returns yet maintains the stability of the new system. Further research is required to bring the farmer's yields up to match experiment station results and to facilitate effective transfer policies.

  17. Cluster analysis of lowland and upland rice cultivars based on grain quality attributes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice is cropped in many countries all over the world and plays an important role in human nutrition as well as in agricultural economics, besides its social importance. Embrapa Rice and Beans is responsible for national rice enhancement programs and is conducting breeding projects to increase yield ...

  18. Seasonal assessment of greenhouse gas emission from irrigated lowland rice field under infrared warming

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice fields are considered as one of the major sources of methane (CH4), and they also emit nitrous oxide (N2O). A field experiment was conducted at the International Rice Research Institute, Philippines, in 2010 – 2011 using a temperature free-air controlled enhancement (T-FACE) system. Our object...

  19. Economy of fertilizer nitrogen through organic sources in rain-fed rice-legume cropping systems in West Bengal, India.

    PubMed

    Puste, A M; Bandyopadhyay, S; Das, D K

    2001-12-11

    Field experiments were conducted at a farmers" plot adjacent to the Regional Research Station, red and laterite zone, Sub-center Sekhampur (Birbhum district) of West Bengal, India, situated 23 degrees 24' N latitude, 87 degrees 24' E longitude, to study the effect of different bio- and organic sources of nutrients instead of total fertilizer N in terms of crop productivity in the sequence and building up of soil fertility. During the wet seasons of 1997 and 1998, 12 combinations of bio- and organic sources (crop residues, well decomposed cow dung, dhanicha as green manure) were substituted for 25-50% of N fertilizer applied on transplanted rice (Cv. IR 36). Subsequently, during the winters of 1997-1998 and 1998-1999, leguminous pulse crops like lentil (Lens culinaris [L.] Medic.), gram ( Cicer arietinum L.) and lathyrus (Lathyrus sativus L.) were grown with and without inoculation of Rhizobium. Results revealed that the application of inorganic N in combination with organic sources exhibited a significant increase in rice yield (3.60-3.84 t ha(-1) ) compared to the yield from sole application of N (3.19-3.26 t ha(-1) ). The study showed that about 25% of total applied N was saved without significant yield reduction with simultaneous improvement of soil physical properties (pH, organic matter, available N, P, K, and CEC). Seed yield of pulses (lentil, gram, and lathyrus) were more pronounced in the treatment inoculated with Rhizobium, with a saving of 42.6-48.4 kg N ha(-1). Therefore, the results suggest that the combined application of inorganic and organic N sources in a 75:25 ratio is a superior N-management practice with regards to crop yields as well as improvement of soil fertility. PMID:12805756

  20. Improving salt tolerance of lowland rice cultivar 'Rassi' through marker-aided backcross breeding in West Africa.

    PubMed

    Bimpong, Isaac Kofi; Manneh, Baboucarr; Sock, Mamadou; Diaw, Faty; Amoah, Nana Kofi Abaka; Ismail, Abdelbagi M; Gregorio, Glenn; Singh, Rakesh Kumar; Wopereis, Marco

    2016-01-01

    Salt stress affects about 25% of the 4.4 million ha of irrigated and lowland systems for rice cultivation in West Africa (WA). A major quantitative trait locus (QTLs) on chromosome 1 (Saltol) that enhances tolerance to salt stress at the vegetative stage has enabled the use of marker-assisted selection (MAS) to develop salt-tolerant rice cultivar(s) in WA. We used 3 cycles of backcrossing with selection based on DNA markers and field-testing using 'FL478' as tolerant donor and the widely grown 'Rassi' as recurrent parent. In the BC3F2 stage, salt-tolerant lines with over 80% Rassi alleles except in the region around Saltol segment were selected. 429 introgression lines (Saltol-ILs) were identified as tolerant at vegetative stage, of which 116 were field-tested for four seasons at the reproductive stage. Sixteen Saltol-ILs had less yield loss (3-26% relative to control trials), and 8 Saltol-ILs showed high yield potential under stress and non-stress conditions. The 16 Saltol-ILs had been included for further African-wide testing prior to release in 6 WA countries. MAS reduced the time for germplasm improvement from at least 7 to about 4 years. Our objective is to combine different genes/QTLs conferring tolerance to stresses under one genetic background using MAS. PMID:26566846

  1. Localized Flux Maxima of Arsenic, Lead, and Iron around Root Apices in Flooded Lowland Rice

    PubMed Central

    2014-01-01

    In wetland-adapted plants, such as rice, it is typically root apexes, sites of rapid entry for water/nutrients, where radial oxygen losses (ROLs) are highest. Nutrient/toxic metal uptake therefore largely occurs through oxidized zones and pH microgradients. However, the processes controlling the acquisition of trace elements in rice have been difficult to explore experimentally because of a lack of techniques for simultaneously measuring labile trace elements and O2/pH. Here, we use new diffusive gradients in thin films (DGT)/planar optode sandwich sensors deployed in situ on rice roots to demonstrate a new geochemical niche of greatly enhanced As, Pb, and Fe(II) mobilization into solution immediately adjacent to the root tips characterized by O2 enrichment and low pH. Fe(II) mobilization was congruent to that of the peripheral edge of the aerobic root zone, demonstrating that the Fe(II) mobilization maximum only developed in a narrow O2 range as the oxidation front penetrates the reducing soil. The Fe flux to the DGT resin at the root apexes was 3-fold higher than the anaerobic bulk soil and 27 times greater than the aerobic rooting zone. These results provide new evidence for the importance of coupled diffusion and oxidation of Fe in modulating trace metal solubilization, dispersion, and plant uptake. PMID:24967508

  2. Improving Lowland Rice (O. sativa L. cv. MR219) Plant Growth Variables, Nutrients Uptake, and Nutrients Recovery Using Crude Humic Substances.

    PubMed

    Palanivell, Perumal; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad; Jalloh, Mohamadu Boyie; Susilawati, Kasim

    2015-01-01

    High cation exchange capacity and organic matter content of crude humic substances from compost could be exploited to reduce ammonia loss from urea and to as well improve rice growth and soil chemical properties for efficient nutrients utilization in lowland rice cultivation. Close-dynamic air flow system was used to determine the effects of crude humic substances on ammonia volatilization. A pot experiment was conducted to determine the effects of crude humic substances on rice plant growth, nutrients uptake, nutrients recovery, and soil chemical properties using an acid soil mixed with three rates of crude humic substances (20, 40, and 60 g pot(-1)). Standard procedures were used to evaluate rice plant dry matter production, nutrients uptake, nutrients recovery, and soil chemical properties. Application of crude humic substances increased ammonia volatilization. However, the lowest rate of crude humic substances (20 g pot(-1)) significantly improved total dry matter, nutrients uptake, nutrients recovery, and soil nutrients availability compared with crude humic substances (40 and 60 g pot(-1)) and the normal fertilization. Apart from improving growth of rice plants, crude humic substances can be used to ameliorate acid soils in rice cultivation. The findings of this study are being validated in our ongoing field trials. PMID:25977938

  3. Improving Lowland Rice (O. sativa L. cv. MR219) Plant Growth Variables, Nutrients Uptake, and Nutrients Recovery Using Crude Humic Substances

    PubMed Central

    Palanivell, Perumal; Ahmed, Osumanu Haruna; Ab Majid, Nik Muhamad; Jalloh, Mohamadu Boyie; Susilawati, Kasim

    2015-01-01

    High cation exchange capacity and organic matter content of crude humic substances from compost could be exploited to reduce ammonia loss from urea and to as well improve rice growth and soil chemical properties for efficient nutrients utilization in lowland rice cultivation. Close-dynamic air flow system was used to determine the effects of crude humic substances on ammonia volatilization. A pot experiment was conducted to determine the effects of crude humic substances on rice plant growth, nutrients uptake, nutrients recovery, and soil chemical properties using an acid soil mixed with three rates of crude humic substances (20, 40, and 60 g pot−1). Standard procedures were used to evaluate rice plant dry matter production, nutrients uptake, nutrients recovery, and soil chemical properties. Application of crude humic substances increased ammonia volatilization. However, the lowest rate of crude humic substances (20 g pot−1) significantly improved total dry matter, nutrients uptake, nutrients recovery, and soil nutrients availability compared with crude humic substances (40 and 60 g pot−1) and the normal fertilization. Apart from improving growth of rice plants, crude humic substances can be used to ameliorate acid soils in rice cultivation. The findings of this study are being validated in our ongoing field trials. PMID:25977938

  4. Nitrogen uptake and use efficiency in rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice is a staple food for a large proportion of the world’s population. Most of the rice is produced and consumed in Asia. Rice is produced in both upland and lowland systems, with about 76% of the global rice produced from irrigated-lowland rice systems. Nitrogen (N) is one of the most important in...

  5. Adaptation to flooding during emergence and seedling growth in rice and weeds, and implications for crop establishment

    PubMed Central

    Ismail, Abdelbagi M.; Johnson, David E.; Ella, Evangelina S.; Vergara, Georgina V.; Baltazar, Aurora M.

    2012-01-01

    Background and aims Direct seeding of rice is being adopted in rainfed and irrigated lowland ecosystems because it reduces labour costs in addition to other benefits. However, early flooding due to uneven fields or rainfall slows down seed germination and hinders crop establishment. Conversely, early flooding helps suppress weeds and reduces the costs of manual weeding and/or dependence on herbicides; however, numerous weed species are adapted to lowlands and present challenges for the use of flooding to control weeds. Advancing knowledge on the mechanisms of tolerance of flooding during germination and early growth in rice and weeds could facilitate the development of improved rice varieties and effective weed management practices for direct-seeded rice. Principal results Rice genotypes with a greater ability to germinate and establish in flooded soils were identified, providing opportunities to develop varieties suitable for direct seeding in flooded soils. Tolerance of flooding in these genotypes was mostly attributed to traits associated with better ability to mobilize stored carbohydrates and anaerobic metabolism. Limited studies were undertaken in weeds associated with lowland rice systems. Remaining studies compared rice and weeds and related weed species such as Echinochloa crus-galli and E. colona or compared ecotypes of the same species of Cyperus rotundus adapted to either aerobic or flooded soils. Conclusions Tolerant weeds and rice genotypes mostly developed similar adaptive traits that allow them to establish in flooded fields, including the ability to germinate and elongate faster under hypoxia, mobilize stored starch reserves and generate energy through fermentation pathways. Remarkably, some weeds developed additional traits such as larger storage tubers that enlarge further in deeper flooded soils (C. rotundus). Unravelling the mechanisms involved in adaptation to flooding will help design management options that will allow tolerant rice genotypes

  6. Rainfed Areas and Animal Agriculture in Asia: The Wanting Agenda for Transforming Productivity Growth and Rural Poverty

    PubMed Central

    Devendra, C.

    2012-01-01

    The importance of rainfed areas and animal agriculture on productivity enhancement and food security for economic rural growth in Asia is discussed in the context of opportunities for increasing potential contribution from them. The extent of the rainfed area of about 223 million hectares and the biophysical attributes are described. They have been variously referred to inter alia as fragile, marginal, dry, waste, problem, threatened, range, less favoured, low potential lands, forests and woodlands, including lowlands and uplands. Of these, the terms less favoured areas (LFAs), and low or high potential are quite widely used. The LFAs are characterised by four key features: i) very variable biophysical elements, notably poor soil quality, rainfall, length of growing season and dry periods, ii) extreme poverty and very poor people who continuously face hunger and vulnerability, iii) presence of large populations of ruminant animals (buffaloes, cattle, goats and sheep), and iv) have had minimum development attention and an unfinished wanting agenda. The rainfed humid/sub-humid areas found mainly in South East Asia (99 million ha), and arid/semi-arid tropical systems found in South Asia (116 million ha) are priority agro-ecological zones (AEZs). In India for example, the ecosystem occupies 68% of the total cultivated area and supports 40% of the human and 65% of the livestock populations. The area also produces 4% of food requirements. The biophysical and typical household characteristics, agricultural diversification, patterns of mixed farming and cropping systems are also described. Concerning animals, their role and economic importance, relevance of ownership, nomadic movements, and more importantly their potential value as the entry point for the development of LFAs is discussed. Two examples of demonstrated success concern increasing buffalo production for milk and their expanded use in semi-arid AEZs in India, and the integration of cattle and goats with oil

  7. Rainfed areas and animal agriculture in Asia: the wanting agenda for transforming productivity growth and rural poverty.

    PubMed

    Devendra, C

    2012-01-01

    The importance of rainfed areas and animal agriculture on productivity enhancement and food security for economic rural growth in Asia is discussed in the context of opportunities for increasing potential contribution from them. The extent of the rainfed area of about 223 million hectares and the biophysical attributes are described. They have been variously referred to inter alia as fragile, marginal, dry, waste, problem, threatened, range, less favoured, low potential lands, forests and woodlands, including lowlands and uplands. Of these, the terms less favoured areas (LFAs), and low or high potential are quite widely used. The LFAs are characterised by four key features: i) very variable biophysical elements, notably poor soil quality, rainfall, length of growing season and dry periods, ii) extreme poverty and very poor people who continuously face hunger and vulnerability, iii) presence of large populations of ruminant animals (buffaloes, cattle, goats and sheep), and iv) have had minimum development attention and an unfinished wanting agenda. The rainfed humid/sub-humid areas found mainly in South East Asia (99 million ha), and arid/semi-arid tropical systems found in South Asia (116 million ha) are priority agro-ecological zones (AEZs). In India for example, the ecosystem occupies 68% of the total cultivated area and supports 40% of the human and 65% of the livestock populations. The area also produces 4% of food requirements. The biophysical and typical household characteristics, agricultural diversification, patterns of mixed farming and cropping systems are also described. Concerning animals, their role and economic importance, relevance of ownership, nomadic movements, and more importantly their potential value as the entry point for the development of LFAs is discussed. Two examples of demonstrated success concern increasing buffalo production for milk and their expanded use in semi-arid AEZs in India, and the integration of cattle and goats with oil

  8. Rainfed farming systems in the USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter on rainfed farming systems in the USA describes characteristics of four major rainfed farming regions in the USA: Great Plains wheat-sorghum-cattle region, midwestern corn-soybean-hogs region, southern cotton-peanut-poultry region, and coastal diversified crops-dairy region. Rainfed fa...

  9. Comparative Transcriptional Profiling of Primed and Non-primed Rice Seedlings under Submergence Stress.

    PubMed

    Hussain, Saddam; Yin, Hanqi; Peng, Shaobing; Khan, Faheem A; Khan, Fahad; Sameeullah, Muhammad; Hussain, Hafiz A; Huang, Jianliang; Cui, Kehui; Nie, Lixiao

    2016-01-01

    Submergence stress is a limiting factor for direct-seeded rice systems in rainfed lowlands and flood-prone areas of South and Southeast Asia. The present study demonstrated that submergence stress severely hampered the germination and seedling growth of rice, however, seed priming alleviated the detrimental effects of submergence stress. To elucidate the molecular basis of seed priming-induced submergence tolerance, transcriptome analyses were performed using 4-day-old primed (selenium-Se and salicylic acid-SA priming) and non-primed rice seedlings under submergence stress. Genomewide transcriptomic profiling identified 2371 and 2405 transcripts with Se- and SA-priming, respectively, that were differentially expressed in rice compared with non-priming treatment under submergence. Pathway and gene ontology term enrichment analyses revealed that genes involved in regulation of secondary metabolism, development, cell, transport, protein, and metal handling were over-represented after Se- or SA-priming. These coordinated factors might have enhanced the submergence tolerance and maintained the better germination and vigorous seedling growth of primed rice seedlings. It was also found that many genes involved in cellular and metabolic processes such as carbohydrate metabolism, cellular, and metabolic biosynthesis, nitrogen compound metabolic process, transcription, and response to oxidative stress were induced and overlapped in seed priming treatments, a finding which reveals the common mechanism of seed priming-induced submergence tolerance. Taken together, these results may provide new avenues for understanding and advancing priming-induced responses to submergence tolerance in crop plants. PMID:27516766

  10. Comparative Transcriptional Profiling of Primed and Non-primed Rice Seedlings under Submergence Stress

    PubMed Central

    Hussain, Saddam; Yin, Hanqi; Peng, Shaobing; Khan, Faheem A.; Khan, Fahad; Sameeullah, Muhammad; Hussain, Hafiz A.; Huang, Jianliang; Cui, Kehui; Nie, Lixiao

    2016-01-01

    Submergence stress is a limiting factor for direct-seeded rice systems in rainfed lowlands and flood-prone areas of South and Southeast Asia. The present study demonstrated that submergence stress severely hampered the germination and seedling growth of rice, however, seed priming alleviated the detrimental effects of submergence stress. To elucidate the molecular basis of seed priming-induced submergence tolerance, transcriptome analyses were performed using 4-day-old primed (selenium-Se and salicylic acid-SA priming) and non-primed rice seedlings under submergence stress. Genomewide transcriptomic profiling identified 2371 and 2405 transcripts with Se- and SA-priming, respectively, that were differentially expressed in rice compared with non-priming treatment under submergence. Pathway and gene ontology term enrichment analyses revealed that genes involved in regulation of secondary metabolism, development, cell, transport, protein, and metal handling were over-represented after Se- or SA-priming. These coordinated factors might have enhanced the submergence tolerance and maintained the better germination and vigorous seedling growth of primed rice seedlings. It was also found that many genes involved in cellular and metabolic processes such as carbohydrate metabolism, cellular, and metabolic biosynthesis, nitrogen compound metabolic process, transcription, and response to oxidative stress were induced and overlapped in seed priming treatments, a finding which reveals the common mechanism of seed priming-induced submergence tolerance. Taken together, these results may provide new avenues for understanding and advancing priming-induced responses to submergence tolerance in crop plants. PMID:27516766

  11. LANDSCAPE CHANGES IN A LOWLAND IN BENIN: ECOLOGICAL IMPACT ON PESTS AND NATURAL ENEMIES.

    PubMed

    Boucher, A; Silvie, P; Menozzi, P; Adda, C; Auzoux, S; Jean, J; Huat, J

    2015-01-01

    Habitat management involving conservative biological control could be a good crop pest management option in poor African countries. A survey was conducted from August 2013 to July 2014 in a rainfed lowland region near Pélébina, northern Benin, in order to characterize spatiotemporal landscape changes and investigate their influence on the main crop pests and their associated natural enemies. The area was mapped mainly regarding crop fields and fallows. Visual observations were recorded and a database was compiled. Major landscape composition changes were noted between rainy and dry seasons, which affected the presence of both pests and natural enemies. Cereals (rice, maize and sorghum) and cotton were grown in the humid season, and then okra (Abelmoschus esculentus) was the dominant vegetable crop in dry season. These modifications impacted fallow abundance throughout the lowland. Different cotton (e.g. Helicoverpa armigera, Dysdercus sp., Zonocerus variegatus) or rice (e.g. Diopsis longicornis, D. apicalis) pests were observed during dry season in okra crops. Dry season surveys of Poaceae in two types of fallows ('humid', 'dry') revealed the presence of very few stem borers: only 0.04% of stems sampled were infested by stem borers, with a mean of 1.13 larvae per stem. Known cereal stem borer species such as Busseola fusco, Coniesta ignefusalis, Sesamia calamistis were not clearly identified among these larvae because of their diapausing stage and white color. Unexpected pollinators (Hymenoptera Apidae, genus Braunsapis, Ceratina and Xylocopa) and predators (Crabronidae, genus Dasyproctus) were found in the stems. Sweep-net collection of insects in humid fallows allowed us to describe for the first time in Benin seven Diopsidae species (23% of adults bearing Laboulbeniomycetes ectoparasitic fungi). Some of these species were captured in rice fields during rainy season. Parasitoids (adult Chalcidoidae and Ichneumonoidae) were observed during both seasons but their

  12. Effects of water-saving irrigation practices and drought resistant rice variety on greenhouse gas emissions from a no-till paddy in the central lowlands of China.

    PubMed

    Xu, Ying; Ge, Junzhu; Tian, Shaoyang; Li, Shuya; Nguy-Robertson, Anthony L; Zhan, Ming; Cao, Cougui

    2015-02-01

    As pressure on water resources increases, alternative practices to conserve water in paddies have been developed. Few studies have simultaneously examined the effectiveness of different water regimes on conserving water, mitigating greenhouse gases (GHG), and maintaining yields in rice production. This study, which was conducted during the drought of 2013, examined all three factors using a split-plot experiment with two rice varieties in a no-till paddy managed under three different water regimes: 1) continuous flooding (CF), 2) flooded and wet intermittent irrigation (FWI), and 3) flooded and dry intermittent irrigation (FDI). The Methane (CH₄) and nitrous oxide (N₂O) emissions were measured using static chamber-gas measurements, and the carbon dioxide (CO₂) emissions were monitored using a soil CO₂ flux system (LI-8100). Compared with CF, FWI and FDI irrigation strategies reduced CH₄ emissions by 60% and 83%, respectively. In contrast, CO₂ and N₂O fluxes increased by 65% and 9%, respectively, under FWI watering regime and by 104% and 11%, respectively, under FDI managed plots. Although CO₂ and N₂O emissions increased, the global warming potential (GWP) and greenhouse gas intensity (GHGI) of all three GHG decreased by up to 25% and 29% (p<0.01), respectively, using water-saving irrigation strategies. The rice variety also affected yields and GHG emissions in response to different water regimes. The drought-resistance rice variety (HY3) was observed to maintain yields, conserve water, and reduce GHG under the FWI irrigation management compared with the typical variety (FYY299) planted in the region. The FYY299 only had significantly lower GWP and GHGI when the yield was reduced under FDI water regime. In conclusion, FWI irrigation strategy could be an effective option for simultaneously saving water and mitigating GWP without reducing rice yields using drought-resistant rice varieties, such as HY3. PMID:25461105

  13. Physiological and Molecular Basis of Susceptibility and Tolerance of Rice Plants to Complete Submergence

    PubMed Central

    JACKSON, MICHAEL B.; RAM, PHOOL C.

    2003-01-01

    Rice plants are much damaged by several days of total submergence. The effect can be a serious problem for rice farmers in the rainfed lowlands of Asia, and runs contrary to a widespread belief amongst plant biologists that rice is highly tolerant of submergence. This article assesses the characteristics of the underwater environment that may damage rice plants, examines various physiological mechanisms of injury, and reviews recent progress achieved using linkage mapping to locate quantitative traits loci (QTL) for tolerance inherited from a submergence‐tolerant cultivar FR13A. Progress towards identifying the gene(s) involved through physical mapping of a dominant tolerance locus on chromosome 9 is also summarized. Available physiological evidence points away from responses to oxygen shortage as being inextricably involved in submergence injury. An imbalance between production and consumption of assimilates is seen as being especially harmful, and is exacerbated by strongly accelerated leaf extension and leaf senescence that are ethylene‐mediated and largely absent from FR13A and related cultivars. DNA markers for a major QTL for tolerance are shown to be potentially useful in breeding programmes designed to improve submergence tolerance. PMID:12509343

  14. Tolerance of anaerobic conditions caused by flooding during germination and early growth in rice (Oryza sativa L.).

    PubMed

    Miro, Berta; Ismail, Abdelbagi M

    2013-01-01

    Rice is semi-aquatic, adapted to a wide range of hydrologies, from aerobic soils in uplands to anaerobic and flooded fields in waterlogged lowlands, to even deeply submerged soils in flood-prone areas. Considerable diversity is present in native rice landraces selected by farmers over centuries. Our understanding of the adaptive features of these landraces to native ecosystems has improved considerably over the recent past. In some cases, major genes associated with tolerance have been cloned, such as SUB1A that confers tolerance of complete submergence and SNORKEL genes that control plant elongation to escape deepwater. Modern rice varieties are sensitive to flooding during germination and early growth, a problem commonly encountered in rainfed areas, but few landraces capable of germination under these conditions have recently been identified, enabling research into tolerance mechanisms. Major QTLs were also identified, and are being targeted for molecular breeding and for cloning. Nevertheless, limited progress has been made in identifying regulatory processes for traits that are unique to tolerant genotypes, including faster germination and coleoptile elongation, formation of roots and leaves under hypoxia, ability to catabolize starch into simple sugars for subsequent use in glycolysis and fermentative pathways to generate energy. Here we discuss the state of knowledge on the role of the PDC-ALDH-ACS bypass and the ALDH enzyme as the likely candidates effective in tolerant rice genotypes. Potential involvement of factors such as cytoplasmic pH regulation, phytohormones, reactive oxygen species scavenging and other metabolites is also discussed. Further characterization of contrasting genotypes would help in elucidating the genetic and biochemical regulatory and signaling mechanisms associated with tolerance. This could facilitate breeding rice varieties suitable for direct seeding systems and guide efforts for improving waterlogging tolerance in other crops

  15. Tolerance of anaerobic conditions caused by flooding during germination and early growth in rice (Oryza sativa L.)

    PubMed Central

    Miro, Berta; Ismail, Abdelbagi M.

    2013-01-01

    Rice is semi-aquatic, adapted to a wide range of hydrologies, from aerobic soils in uplands to anaerobic and flooded fields in waterlogged lowlands, to even deeply submerged soils in flood-prone areas. Considerable diversity is present in native rice landraces selected by farmers over centuries. Our understanding of the adaptive features of these landraces to native ecosystems has improved considerably over the recent past. In some cases, major genes associated with tolerance have been cloned, such as SUB1A that confers tolerance of complete submergence and SNORKEL genes that control plant elongation to escape deepwater. Modern rice varieties are sensitive to flooding during germination and early growth, a problem commonly encountered in rainfed areas, but few landraces capable of germination under these conditions have recently been identified, enabling research into tolerance mechanisms. Major QTLs were also identified, and are being targeted for molecular breeding and for cloning. Nevertheless, limited progress has been made in identifying regulatory processes for traits that are unique to tolerant genotypes, including faster germination and coleoptile elongation, formation of roots and leaves under hypoxia, ability to catabolize starch into simple sugars for subsequent use in glycolysis and fermentative pathways to generate energy. Here we discuss the state of knowledge on the role of the PDC-ALDH-ACS bypass and the ALDH enzyme as the likely candidates effective in tolerant rice genotypes. Potential involvement of factors such as cytoplasmic pH regulation, phytohormones, reactive oxygen species scavenging and other metabolites is also discussed. Further characterization of contrasting genotypes would help in elucidating the genetic and biochemical regulatory and signaling mechanisms associated with tolerance. This could facilitate breeding rice varieties suitable for direct seeding systems and guide efforts for improving waterlogging tolerance in other crops

  16. Monsoon variability, crop water requirement, and crop planning for kharif rice in Sagar Island, India.

    PubMed

    Mandal, S; Choudhury, B U; Satpati, L N

    2015-12-01

    In the Sagar Island of Bay of Bengal, rainfed lowland rice is the major crop, grown solely depending on erratic distribution of southwest monsoon (SM) rainfall. Lack of information on SM rainfall variability and absence of crop scheduling accordingly results in frequent occurrence of intermittent water stress and occasional crop failure. In the present study, we analyzed long period (1982-2010) SM rainfall behavior (onset, withdrawal, rainfall and wetness indices, dry and wet spells), crop water requirement (CWR, by Food and Agriculture Organization (FAO) 56), and probability of weekly rainfall occurrence (by two-parameter gamma distribution) to assess the variability and impact on water availability, CWR, and rice productivity. Finally, crop planning was suggested to overcome monsoon uncertainties on water availability and rice productivity. Study revealed that the normal onset and withdrawal weeks for SM rainfall were 22nd ± 1 and 43rd ± 2 meteorological weeks (MW), respectively. However, effective monsoon rainfall started at 24th MW (rainfall 92.7 mm, p > 56.7 % for 50 mm rainfall) and was terminated by the end of 40th MW (rainfall 90.7 mm, p < 59.6 % for 50 mm rainfall). During crop growth periods (seed to seed, 21st to 45th MW), the island received an average weekly rainfall of 65.1 ± 25.9 mm, while the corresponding weekly CWR was 47.8 ± 5.4 mm. Despite net water surplus of 353.9 mm during crop growth periods, there was a deficit of 159.5 mm water during MW of 18-23 (seedling raising) and MW of 41-45 (flowering to maturity stages). Water stress was observed in early lag vegetative stage of crop growth (32nd MW). The total dry spell frequency during panicle initiation and heading stage was computed as 40 of which 6 dry spells were >7 days in duration and reflected a significant (p < 0.05) increasing trend (at 0.22 days year(-1)) over the years (1982-2010). The present study highlights the adaptive capacity of crop planning

  17. Monsoon variability, crop water requirement, and crop planning for kharif rice in Sagar Island, India

    NASA Astrophysics Data System (ADS)

    Mandal, S.; Choudhury, B. U.; Satpati, L. N.

    2015-12-01

    In the Sagar Island of Bay of Bengal, rainfed lowland rice is the major crop, grown solely depending on erratic distribution of southwest monsoon (SM) rainfall. Lack of information on SM rainfall variability and absence of crop scheduling accordingly results in frequent occurrence of intermittent water stress and occasional crop failure. In the present study, we analyzed long period (1982-2010) SM rainfall behavior (onset, withdrawal, rainfall and wetness indices, dry and wet spells), crop water requirement (CWR, by Food and Agriculture Organization (FAO) 56), and probability of weekly rainfall occurrence (by two-parameter gamma distribution) to assess the variability and impact on water availability, CWR, and rice productivity. Finally, crop planning was suggested to overcome monsoon uncertainties on water availability and rice productivity. Study revealed that the normal onset and withdrawal weeks for SM rainfall were 22nd ± 1 and 43rd ± 2 meteorological weeks (MW), respectively. However, effective monsoon rainfall started at 24th MW (rainfall 92.7 mm, p > 56.7 % for 50 mm rainfall) and was terminated by the end of 40th MW (rainfall 90.7 mm, p < 59.6 % for 50 mm rainfall). During crop growth periods (seed to seed, 21st to 45th MW), the island received an average weekly rainfall of 65.1 ± 25.9 mm, while the corresponding weekly CWR was 47.8 ± 5.4 mm. Despite net water surplus of 353.9 mm during crop growth periods, there was a deficit of 159.5 mm water during MW of 18-23 (seedling raising) and MW of 41-45 (flowering to maturity stages). Water stress was observed in early lag vegetative stage of crop growth (32nd MW). The total dry spell frequency during panicle initiation and heading stage was computed as 40 of which 6 dry spells were >7 days in duration and reflected a significant ( p < 0.05) increasing trend (at 0.22 days year-1) over the years (1982-2010). The present study highlights the adaptive capacity of crop planning including abiotic stress

  18. Rain-fed fig yield as affected by rainfall distribution

    NASA Astrophysics Data System (ADS)

    Bagheri, Ensieh; Sepaskhah, Ali Reza

    2014-08-01

    Variable annual rainfall and its uneven distribution are the major uncontrolled inputs in rain-fed fig production and possibly the main cause of yield fluctuation in Istahban region of Fars Province, I.R. of Iran. This introduces a considerable risk in rain-fed fig production. The objective of this study was to find relationships between seasonal rainfall distribution and rain-fed fig production in Istahban region to determine the critical rainfall periods for rain-fed fig production and supplementary irrigation water application. Further, economic analysis for rain-fed fig production was considered in this region to control the risk of production. It is concluded that the monthly, seasonal and annual rainfall indices are able to show the effects of rainfall and its distribution on the rain-fed fig yield. Fig yield with frequent occurrence of 80 % is 374 kg ha-1. The internal rates of return for interest rate of 4, 8 and 12 % are 21, 58 and 146 %, respectively, that are economically feasible. It is concluded that the rainfall in spring especially in April and in December has negatively affected fig yield due to its interference with the life cycle of Blastophaga bees for pollination. Further, it is concluded that when the rainfall is limited, supplementary irrigation can be scheduled in March.

  19. Soil carbon sequestration in rainfed production systems in the semiarid tropics of India.

    PubMed

    Srinivasarao, Ch; Lal, Rattan; Kundu, Sumanta; Babu, M B B Prasad; Venkateswarlu, B; Singh, Anil Kumar

    2014-07-15

    Severe soil organic carbon (SOC) depletion is a major constraint in rainfed agroecosystems in India because it directly influences soil quality, crop productivity and sustainability. The magnitude of soil organic, inorganic and total carbon stocks in the semi-arid bioclimate is estimated at 2.9, 1.9 and 4.8 Pg respectively. Sorghum, finger millet, pearl millet, maize, rice, groundnut, soybean, cotton, food legumes etc. are predominant crop production systems with a little, if any, recycling of organic matter. Data from the long term experiments on major rainfed production systems in India show that higher amount of crop residue C input (Mg/ha/y) return back to soil in soybean-safflower (3.37) system practiced in Vertisol region of central India. Long term addition of chemical fertilizer and organic amendments improved the SOC stock. For every Mg/ha increase in SOC stock in the root zone, there occurs an increase in grain yield (kg/ha) of 13, 101, 90, 170, 145, 18 and 160 for groundnut, finger millet, sorghum, pearl millet, soybean and rice, respectively. Long-term cropping without using any organic amendment and/or mineral fertilizers can severely deplete the SOC stock which is the highest in groundnut-finger millet system (0.92 Mg C/ha/y) in Alfisols. Some agroforestry systems also have a huge potential of C sequestration to the extent of 10Mg/ha/y in short rotation eucalyptus and Leucaena plantations. The critical level of C input requirements for maintaining SOC at the antecedent level ranges from 1.1 to 3.5 Mg C/ha/y and differs among soil type and production systems. National level policy interventions needed to promote sustainable use of soil and water resources include prohibiting residue burning, reducing deforestation, promoting integrated farming systems and facilitating payments for ecosystem services. A wide spread adoption of these measures can improve soil quality through increase in SOC sequestration and improvement in agronomic productivity of

  20. Identification of Striga hermonthica-Resistant Upland Rice Varieties in Sudan and Their Resistance Phenotypes.

    PubMed

    Samejima, Hiroaki; Babiker, Abdel G; Mustafa, Ahmed; Sugimoto, Yukihiro

    2016-01-01

    Rice has become a major staple cereal in sub-Saharan Africa. Currently, upland rice cultivation is expanding particularly in rainfed areas where the root parasitic weed Striga hermonthica, a major constraint to cereal production, is endemic. Laboratory, pot, and semi-controlled open air experiments were performed to evaluate resistance of selected rice varieties in Sudan to a resident S. hermonthica population. In the laboratory, 27 varieties were screened for post-attachment resistance using the rhizotron technique. Varieties displaying high post-attachment resistance, Umgar, NERICA5, and NERICA13 together with NERICA4, NERICA18, and Nipponbare, a lowland rice variety, were further evaluated for performance and Striga resistance in pot and semi-controlled open air experiments and for germination inducing activity in a laboratory. In addition, comparative studies on reaction of Umgar, Kosti1 and Kosti2, released varieties for commercial production in Sudan, to the parasite were performed in two pot experiments. In the pot experiments Umgar and NERICA5, consistently, sustained the lowest Striga emergence (<2.2 Striga plants per pot), while NERICA13 and NERICA4 supported 1.8-5.7 and 8.7-16.4 Striga plants per pot, respectively. In an artificially Striga-infested field, number of emergent Striga plants per 10 rice hills, at harvest, was 2.0, 2.0, 4.8, 13.5, 13.3, and 18.3 on Umgar, NERICA5, NERICA13, NERICA4, NERICA18, and Nipponbare, respectively. Striga had no adverse effects on total above-ground parts and panicle dry weight in Umgar and NERICA5. Germination-inducing activity of root exudates, at 14 days after sowing onward, was markedly lower for Umgar than for NERICA5, NERICA13, NERICA4, and NERICA18. Based on these findings, Umgar has both pre and post-attachment resistance to a resident Striga population in Sudan. Kosti1 and Kosti2 did not exhibit Striga-resistance at the same level as Umgar. Further the resistance of NERICA5, a variety reported to be endowed

  1. Identification of Striga hermonthica-Resistant Upland Rice Varieties in Sudan and Their Resistance Phenotypes

    PubMed Central

    Samejima, Hiroaki; Babiker, Abdel G.; Mustafa, Ahmed; Sugimoto, Yukihiro

    2016-01-01

    Rice has become a major staple cereal in sub-Saharan Africa. Currently, upland rice cultivation is expanding particularly in rainfed areas where the root parasitic weed Striga hermonthica, a major constraint to cereal production, is endemic. Laboratory, pot, and semi-controlled open air experiments were performed to evaluate resistance of selected rice varieties in Sudan to a resident S. hermonthica population. In the laboratory, 27 varieties were screened for post-attachment resistance using the rhizotron technique. Varieties displaying high post-attachment resistance, Umgar, NERICA5, and NERICA13 together with NERICA4, NERICA18, and Nipponbare, a lowland rice variety, were further evaluated for performance and Striga resistance in pot and semi-controlled open air experiments and for germination inducing activity in a laboratory. In addition, comparative studies on reaction of Umgar, Kosti1 and Kosti2, released varieties for commercial production in Sudan, to the parasite were performed in two pot experiments. In the pot experiments Umgar and NERICA5, consistently, sustained the lowest Striga emergence (<2.2 Striga plants per pot), while NERICA13 and NERICA4 supported 1.8–5.7 and 8.7–16.4 Striga plants per pot, respectively. In an artificially Striga-infested field, number of emergent Striga plants per 10 rice hills, at harvest, was 2.0, 2.0, 4.8, 13.5, 13.3, and 18.3 on Umgar, NERICA5, NERICA13, NERICA4, NERICA18, and Nipponbare, respectively. Striga had no adverse effects on total above-ground parts and panicle dry weight in Umgar and NERICA5. Germination-inducing activity of root exudates, at 14 days after sowing onward, was markedly lower for Umgar than for NERICA5, NERICA13, NERICA4, and NERICA18. Based on these findings, Umgar has both pre and post-attachment resistance to a resident Striga population in Sudan. Kosti1 and Kosti2 did not exhibit Striga-resistance at the same level as Umgar. Further the resistance of NERICA5, a variety reported to be

  2. Genome-Wide Association Mapping of Root Traits in a Japonica Rice Panel

    PubMed Central

    Courtois, Brigitte; Audebert, Alain; Dardou, Audrey; Roques, Sandrine; Ghneim- Herrera, Thaura; Droc, Gaëtan; Frouin, Julien; Rouan, Lauriane; Gozé, Eric; Kilian, Andrzej; Ahmadi, Nourollah; Dingkuhn, Michael

    2013-01-01

    Rice is a crop prone to drought stress in upland and rainfed lowland ecosystems. A deep root system is recognized as the best drought avoidance mechanism. Genome-wide association mapping offers higher resolution for locating quantitative trait loci (QTLs) than QTL mapping in biparental populations. We performed an association mapping study for root traits using a panel of 167 japonica accessions, mostly of tropical origin. The panel was genotyped at an average density of one marker per 22.5 kb using genotyping by sequencing technology. The linkage disequilibrium in the panel was high (r2>0.6, on average, for 20 kb mean distances between markers). The plants were grown in transparent 50 cm × 20 cm × 2 cm Plexiglas nailboard sandwiches filled with 1.5 mm glass beads through which a nutrient solution was circulated. Root system architecture and biomass traits were measured in 30-day-old plants. The panel showed a moderate to high diversity in the various traits, particularly for deep (below 30 cm depth) root mass and the number of deep roots. Association analyses were conducted using a mixed model involving both population structure and kinship to control for false positives. Nineteen associations were significant at P<1e-05, and 78 were significant at P<1e-04. The greatest numbers of significant associations were detected for deep root mass and the number of deep roots, whereas no significant associations were found for total root biomass or deep root proportion. Because several QTLs for different traits were co-localized, 51 unique loci were detected; several co-localized with meta-QTLs for root traits, but none co-localized with rice genes known to be involved in root growth. Several likely candidate genes were found in close proximity to these loci. Additional work is necessary to assess whether these markers are relevant in other backgrounds and whether the genes identified are robust candidates. PMID:24223758

  3. Soil water availability and capacity of nitrogen accumulation influence variations of intrinsic water use efficiency in rice.

    PubMed

    Xue, Wei; Nay-Htoon, Bhone; Lindner, Steve; Dubbert, Maren; Otieno, Dennis; Ko, Jonghan; Werner, Christiane; Tenhunen, John

    2016-04-01

    Leaf intrinsic water use efficiency (WUEi) coupling maximum assimilation rate (Amax) and transpirable water lost via stomatal conductance (gsc) has been gaining increasing concern in sustainable crop production. Factors that influence leaf Amax and WUEi in rice (Oryza sativa L. cv Unkang) at flooding and rainfed conditions were evaluated. Positive correlations for leaf nitrogen content (Nm) and maximum carboxylation rate (Vcmax), for nitrogen allocation in Rubisco enzymes and mesophyll conductance (gm) were evident independent of cropping cultures. Rainfed rice exhibited enriched canopy leaf average Nm resulting in higher Amax, partially supporting improved leaf WUEi. Maximum WUEi (up to 0.14μmolmmol(-1)) recorded in rainfed rice under drought conditions resulted from increasing gm/gsc ratio while at cost of significant decline in Amax due to hydraulically constrained gsc. Amax sensitivity related to gsc which was regulated by plant hydraulic conductance. WUEi was tightly correlated to Vcmax/gsc and gm/gsc ratios across the paddy and rainfed not to light environment, morphological and physiological traits, highlighting enhance capacity of Nm accumulation in rainfed rice with gsc at moderately high level similar to paddy rice facilitate optimization in Amax and WUEi while, is challenged by drought-vulnerable plant hydraulic conductance. PMID:26938938

  4. Calibration of Daycent biogeochemical model for rice paddies in three agro-ecological zones in Peninsular India to optimize cropping practices and predict GHG emissions

    NASA Astrophysics Data System (ADS)

    Rajan, S.; Kritee, K.; Keough, C.; Parton, W. J.; Ogle, S. M.

    2014-12-01

    Rice is a staple for nearly half of the world population with irrigated and rainfed lowland rice accounting for about 80% of the worldwide harvested rice area. Increased atmospheric CO2 and rising temperatures are expected to adversely affect rice yields by the end of the 21st century. In addition, different crop management practices affect methane and nitrous oxide emissions from rice paddies antagonistically warranting a review of crop management practices such that farmers can adapt to the changing climate and also help mitigate climate change. The Daily DayCent is a biogeochemical model that operates on a daily time step, driven by four ecological drivers, i.e. climate, soil, vegetation, and management practices. The model is widely used to simulate daily fluxes of various gases, plant productivity, nutrient availability, and other ecosystem parameters in response to changes in land management and climate. We employed the DayCent model as a tool to optimize rice cropping practices in Peninsular India so as to develop a set of farming recommendations to ensure a triple win (i.e. higher yield, higher profit and lower GHG emissions). We applied the model to simulate both N2O and CH4 emissions, and crop yields from four rice paddies in three different agro-ecological zones under different management practices, and compared them with measured GHG and yield data from these plots. We found that, like all process based models, the biggest constraint in using the model was input data acquisition. Lack of accurate documentation of historic land use and management practices, missing historical daily weather data, and difficulty in obtaining digital records of soil and crop/vegetation parameters related to our experimental plots came in the way of our execution of this model. We will discuss utilization of estimates based on available literature, or knowledge-based values in lieu of missing measured parameters in our simulations with DayCent which could prove to be a

  5. Multiple major QTL lead to stable yield performance of rice cultivars across varying drought intensities

    PubMed Central

    2014-01-01

    Background Availability of irrigation water is becoming a major limiting factor in rice cultivation. Production in rainfed areas is affected in particular by drought events, as these areas are commonly planted to high-yielding drought-susceptible rice (Oryza sativa L.) varieties. The use of bulk segregant analysis (BSA), taking grain yield (GY) as a selection criterion, has resulted in the identification of several large-effect QTL. A QTL mapping study was undertaken on a BC1F3:4 population developed from the cross IR55419-04/2*TDK1 with the aim of identifying large-effect QTL in the background of TDK1, a popular variety from Lao PDR. Results The study identified three QTL—qDTY 3.1 (RM168-RM468), qDTY 6.1 (RM586-RM217), and qDTY 6.2 (RM121-RM541)—for grain yield under drought. qDTY 3.1 and qDTY 6.1 , showed consistent effect across seasons under lowland drought-stress conditions while qDTY 6.1 and qDTY 6.2 showed effect under both upland and lowland drought conditions. The test of QTL effect, conducted through a QTL class analysis, showed the complimentary nature of qDTY 3.1 and qDTY 6.1 . Both QTL showed specific patterns of effect across different maturity groups within the mapping population and higher stability for grain yield was seen across stress levels for lines with both QTLs as compared to those with single or no QTL. Conclusions The study offers a clear understanding of large-effect QTL for grain yield under drought and their effect as individual QTL and in various combinations. The study also opens up an opportunity to develop a drought-tolerant version of TDK1 through marker-assisted backcross breeding and has led to a large-scale QTL pyramiding program aiming to combine these QTL with Sub1 in the background of TDK1 as recipient variety. PMID:24491154

  6. Blackbirds and the southern rice crop

    USGS Publications Warehouse

    Meanley, Brooke

    1971-01-01

    In the 1700's and 1800's, rice was grown in the lowlands of South Carolina, Georgia, and North Carolina - on the major migratory route of the bobolink (Dolichonyx oryzivorus), the historic "ricebird" of that area because of its consumption of ripening rice. By the late 1800's the rice-growing industry had largely shifted to the coastal prairies of Louisiana and Texas, which are bordered by some 5 million acres of marshland-breeding habitat for the redwinged blackbird (Agelaius phoeniceus) and the boat-tailed grackle (Cassidix mexicanus). By 1900, rice was being grown on the Grand Prairie of eastern Arkansas, which bestrides the largest blackbird flyway in the country. In recent decades, rice culture has spread to other sections of Arkansas and thence to contiguous areas in Louisiana, Mississippi, Tennesee, and Missouri. In effect, then, man has taken the rice to the blackbirds.

  7. Abandoned Rice Fields Make Streams Go Dry in Upland Landscapes

    NASA Astrophysics Data System (ADS)

    Jayawickreme, D.

    2015-12-01

    In South Asia, new economic realities are driving many rural rice farmers out of agriculture. With increasing neglect, abandonment, and rising conversions of centuries old rice fields into other uses, ecological and environmental consequences of these transitions are becoming progressively clear. Field observations in Sri Lanka's central highlands suggest that small shifts in rice to non-rice land uses in headwater watersheds can have a domino effect on the productivity and viability of rice fields and other ecological systems downstream by inflicting groundwater recharge reductions, lowering groundwater yields, and causing other hydrological changes. Preliminary analysis shows that although rice itself is a very water intensive crop, the presence of rain-fed upland rice-fields is hugely beneficial to the watersheds they reside. In particular, water benefits of rice appear to be derived from ponded conditions (3-5 inches of standing water) in which rice is grown, and the contribution rice fields makes to enhance water retention and storage capacity of their watersheds during the monsoon season that coincide with the cropping season. In the absence of well managed rice-fields, hilly upland landscapes produce more runoff and retain little rainwater during the wet season. Furthermore, after centuries of intensive use, much of South Asia's rice fields are nutrient poor and minimally productive without fertilizer applications and other interventions. Consequently, when abandoned, soil erosion and other impacts that affect aquatic ecosystems and watershed health also emerge. Despite these multiple concerns however, little research is currently done to better understand the environmental significance of rice cultivations that are a dominant land-use in many South Asian landscapes. The aim of this presentation is to stir interest among the scientific community to engage more broadly in rice, water, and environmental change research in the face of new economic realities in

  8. Behavior of iodine-129 in rice paddy fields

    SciTech Connect

    Uchida, Shigeo; Muramatsu, Yasuyuki

    1995-12-31

    Transfer factors of iodine from soil to rice were obtained by laboratory experiments using {sup 125}I tracer. Two typical soil types in Japan, Andosol and Gray lowland soil, were used. The transfer factor (TF) is defined as concentration of the nuclide in a plant organ at harvest divided by concentration of the nuclide in dry soil. The TFs for brown (hulled) rice were 0.006 for Andosol and 0.002 for Gray lowland soil. The TFs for different organs of rice plants decreased in the order of blade > stem > rachis > unhulled rice {much_gt} brown rice. The concentration of iodine in soil solution under flooded conditions varied with time during cultivation. The iodine concentration in rice plants seemed to be influenced by the soil solution. The effect of removal of I-129 from paddy fields by harvesting rice plants was also modeled. Even assuming continuous deposition of I-129 on the field, annual harvesting of the blades and stems of rice plants could effectively reduce the amount of the nuclide in the root zone.

  9. Stabilized nitrogen fertilizers and application rate influence nitrogen losses under rainfed spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) losses associated with fertilizer application have negative economic and environmental consequences, but urease and nitrification inhibitors have potential to reduce N losses. The effectiveness of these inhibitors has been studied extensively in irrigated but not rainfed systems. Theref...

  10. The water budget of rainfed maize and bean intercrop

    NASA Astrophysics Data System (ADS)

    Walker, S.; Ogindo, H. O.

    Food production in the South African Development Community (SADC) region is predominantly under rainfed conditions and therefore experiences annual fluctuations due to the rainfall variability. Although the staple food of maize ( Zea mays) is commonly grown in the same field as dry beans ( Phaseolus vulgaris) little work has been done to characterize the soil water budget of this intercropping system. The evapotranspiration can theoretically be divided into transpiration from the leaves and evaporation from the soil surface. However, it is difficult to separate the components in field studies. In this paper the Ritchie model is used to estimate the soil surface evaporation using the fractional radiation interception which depends on the crop leaf area. The intercropping system has higher leaf area than the sole crops of both maize and beans in all seasons. Therefore, the soil surface is shaded and the canopy is more dense resulting in a lower soil surface evaporation. The water budget thus gives a higher value of transpiration for the intercrop during each of the four growing seasons. This appears to be due to the complimentary use of the water resources by the maize and bean plants in the intercropping system. This illustrates the ability of the intercrop to use the available soil water in a semi-arid environment more productively. Thus the experience of the small-holder farmers in the SADC region is based on sound physical principles of water use by the two crops.

  11. Variation in tolerance of rice to long-term stagnant flooding that submerges most of the shoot will aid in breeding tolerant cultivars

    PubMed Central

    Vergara, Georgina V.; Nugraha, Yudhistira; Esguerra, Manuel Q.; Mackill, David J.; Ismail, Abdelbagi M.

    2014-01-01

    Stagnant flooding (SF) is a major problem in rainfed lowlands where floodwater of 25–50 cm stagnates in the field for most of the season. We aimed to establish a system for phenotyping SF tolerance and identifying tolerant germplasm through screening of landraces. A total of 626 rice accessions were evaluated over 3 years under control conditions and two levels of SF. Floodwater was raised to 20 cm at 25 or 30 days after transplanting (DAT). In one trial, the depth was increased subsequently by 5 cm a week and in another (severe stress), it was increased to 40 cm at 37 DAT and to 50 cm at 42 DAT. In both trials, water depth was maintained at 50–60 cm until maturity. In all cases, no plant was completely submerged. Plant height, elongation rate and yield were measured at maturity. Genotypes best suited to SF showed moderate elongation of 1.3–2.3 cm day−1 under SF. In contrast, semi-dwarf and fast-elongating types performed poorly. Subsequent trials using 18 genotypes, including six pairs of near isogenic lines (NILs) with or without SUB1 showed that all SUB1 NILs were sensitive to SF. Five of the other six genotypes contained SUB1 and were SF tolerant, suggesting the possibility of combining tolerances to complete submergence (SUB1) and SF. Stem starch and soluble sugar concentrations were similar under control conditions among the 18 genotypes, but starch was depleted by 37 % under SF, with less depletion in tolerant genotypes. SUB1 NILs contained similar concentrations of starch and sugars under SF. We conclude that survival and yield under SF are dependent on moderate elongation, high tillering, lesser carbohydrate depletion and higher fertility. The tolerant genotypes identified here performed strongly in both wet and dry seasons and will be used to identify tolerance mechanisms and alleles for use in marker-assisted breeding. PMID:25202124

  12. Variation in tolerance of rice to long-term stagnant flooding that submerges most of the shoot will aid in breeding tolerant cultivars.

    PubMed

    Vergara, Georgina V; Nugraha, Yudhistira; Esguerra, Manuel Q; Mackill, David J; Ismail, Abdelbagi M

    2014-01-01

    Stagnant flooding (SF) is a major problem in rainfed lowlands where floodwater of 25-50 cm stagnates in the field for most of the season. We aimed to establish a system for phenotyping SF tolerance and identifying tolerant germplasm through screening of landraces. A total of 626 rice accessions were evaluated over 3 years under control conditions and two levels of SF. Floodwater was raised to 20 cm at 25 or 30 days after transplanting (DAT). In one trial, the depth was increased subsequently by 5 cm a week and in another (severe stress), it was increased to 40 cm at 37 DAT and to 50 cm at 42 DAT. In both trials, water depth was maintained at 50-60 cm until maturity. In all cases, no plant was completely submerged. Plant height, elongation rate and yield were measured at maturity. Genotypes best suited to SF showed moderate elongation of 1.3-2.3 cm day(-1) under SF. In contrast, semi-dwarf and fast-elongating types performed poorly. Subsequent trials using 18 genotypes, including six pairs of near isogenic lines (NILs) with or without SUB1 showed that all SUB1 NILs were sensitive to SF. Five of the other six genotypes contained SUB1 and were SF tolerant, suggesting the possibility of combining tolerances to complete submergence (SUB1) and SF. Stem starch and soluble sugar concentrations were similar under control conditions among the 18 genotypes, but starch was depleted by 37 % under SF, with less depletion in tolerant genotypes. SUB1 NILs contained similar concentrations of starch and sugars under SF. We conclude that survival and yield under SF are dependent on moderate elongation, high tillering, lesser carbohydrate depletion and higher fertility. The tolerant genotypes identified here performed strongly in both wet and dry seasons and will be used to identify tolerance mechanisms and alleles for use in marker-assisted breeding. PMID:25202124

  13. Methane Emissions From Global Paddy Rice Agriculture - a New Estimate Based on DNDC Model Simulations

    NASA Astrophysics Data System (ADS)

    Hagen, S. C.; Li, C.; Salas, W.; Ingraham, P.; Li, J.; Beach, R.; Frolking, S.

    2012-12-01

    Roughly one-quarter of global methane emissions to the atmosphere come from the agricultural sector. Agricultural emissions are dominated by livestock (ruminants) and paddy-rice agriculture. We report on a new estimate of global methane emissions from paddy rice c.2010, based on DNDC model simulations of rice cropping around the world. We first generated a global map of rice cropping at 0.5°-resolution, based on existing global crop maps and various other published data. For each 0.5° grid cell that has rice agriculture, we simulated all rice cropping systems that our mapping indicated to be occurring there - irrigated and/or rainfed; single-rice, double-rice, triple-rice, and/or rice-rotated with other upland crops - under local climate and soil conditions, with assumptions about crop management (e.g., fertilizer type and amount, irrigation, flooding frequency and duration, manure application, tillage, crop residue management). We estimate global paddy rice emissions at 23 Tg CH4/yr from 120 Mha of rice paddies (land area) and 160 Mha of rice cropping (harvested area) for the baseline management scenario. We also report on the spatial distribution of these emissions, and the impacts of various management alternatives (flooding methods, fertilizer types, crop residue incorporation etc.) on yield, soil carbon sequestration and emissions of methane and nitrous oxide. For example, simulations with continuous flooding on all paddies increased simulated global paddy rice emissions to 33 Tg CH4/yr, while simulations where all fertilizer was applied as ammonium sulfate reduced simulated global paddy rice emissions to about 19 Tg CH4/yr. Simulated global paddy rice yield was about 320 Tg C in grain.

  14. Rice Nutrition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter presents the symptoms of deficiency and toxicity of the major and minor mineral nutrients in rice, as well as a current synopsis of nutrient transporters and their regulation. The availability of sequences from the recently completed rice genome has furthered the knowledge of how plants...

  15. The archaeobotany of Asian rice expansion and the development of wet-field cultivation

    NASA Astrophysics Data System (ADS)

    Fuller, D.

    2008-12-01

    Archaeobotanical evidence provides direct data on past human diet and agriculture, including a geographical and chronological framework for studying the expansion of rice agriculture. The growth of systematic archaeobotanical sampling in recent years has allowed for the past presence of rice to be seen in relation to cultivation of other crops and associated weeds. The weed flora provides a basis for inferring the nature of cultivation systems, whether rain-fed dry rice or wetland "paddy" rice, a key distinction for considerations of past methane production. Nevertheless, current data is very unevenly distributed. This poster will summarize available evidence for the origins and spread of rice in South Asia (India and Pakistan), and mainland and Island Southeast Asia deriving from an earlier Chinese domestication. Where possible, such as in India or China, the potential of the weed flora remains for distinguishing wetland rice crops will be summarized. In broad terms, although the origins of rice use and cultivation begins by or during the Middle Holocene (6000- 3000 BC), rice cultivation spread outside the regions of the wild progenitor after this time. Two phases of rice expansion can be distinguished. Phase 1, between 3000 and 1500 BC, introduced rice to Southeast Asia, probably under wetland cultivation, and the spread of dry rice over northern India and Pakistan. Phase 2, taking place between 1000 and 0 BC, sees the spread of rice throughout the Southern Indian Peninsula, with weed evidence suggesting irrigated wetland rice. Similarly, this period sees the spread of intensive paddy agriculture through Korea and Japan, but in Southeast Asia is probably related to a spread of rice in upland, dry field systems.

  16. Nitrous oxide emissions with enhanced efficiency nitrogen fertilizers in rainfed system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of enhanced efficiency nitrogen (N) fertilizers can increase crop N utilization and lead to lower emissions of the greenhouse gas nitrous oxide (N2O). To determine potential benefit of four enhanced efficiency fertilizers with rain-fed corn production in central Pennsylvania, USA, N2O emissi...

  17. Gas and Water Vapor Exchanges in Rainfed Corn-Soybean Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn and soybean production in the Midwestern United States represents one of the most intensive and extensive cropping systems in the world. It is critical to understand the dynamics of CO2 (carbon dioxide) and H2O (water) vapor exchanges above corn and soybean canopies in rainfed environments in o...

  18. The application of a Hybrid Evapotranspiration approach in rainfed wheat

    NASA Astrophysics Data System (ADS)

    Geli, Hatim; González-Piqueras, Jose; Torrres, Enrique; Campos, Isidro; Neale, Christopher; Calera, Alfonso

    2013-04-01

    The spatio-temporal estimates of evapotranspiration (ET) have been traditionally addressed applying the water balance (WB) model of the root zone using the FAO-56 approach. The WB model is a prognostic approach of obtaining estimates of the ET and soil moisture on a daily basis. The reflectance based basal-crop coefficient Ksbrf in the WB model is determined from remote sensing data instead of the tabulated averaged basal crop coefficients (Kcb). This improvement over tabulated Kc describes the actual temporal and spatial variability and the growing conditions pattern within the field. Maps of spatially distributed actual ET are obtained applying a two source energy balance (TSEB) Model of Norman et al. (1995), which provides instantaneous estimates of surface energy fluxes including the latent heat flux that can be extrapolated to daily estimates of ET. The soil moisture (SM) plays a key-role in understanding the spatial and temporal variability for improved estimates of both SM and ET. A multiple layer model simulating the dynamics in the soil profile has been used in order to better describe the SM status obtained using the FAO-56 model that considers a single value in the root zone. The SM content is very important in semiarid areas where the crops can develop their roots under water stress environments. Estimates of ET from the TSEB and WB models are independent and can be combined using data assimilation techniques. This hybrid ET approach as described by Geli (2012) and Neale et al. (2012) provides improved estimates of both ET and SM of the root zone and was also applied to irrigated and non-irrigated cotton grown under highly convective conditions. In this work the hybrid ET approach is applied to a rainfed wheat area of 18 ha in extension in La Mancha, Spain (39° 17´N, 1° 59'W, 700 m amsl) during the growing season of 2006. The area has a Mediterranean climate, considered semi-arid with scarce rain with a total of 122 mm measured throughout the growing

  19. ULTRAVIOLET-B RADIATION EFFECTS ON GROWTH AND PHYSIOLOGY OF FOUR RICE CULTIVARS

    EPA Science Inventory

    Enhanced ultraviolet-B radiation, such as could be caused by stratospheric O3 depletion, has been demonstrated to profoundly affect plants. his study was conducted to determine the effects of UV-B on four high-yielding, lowland rice cultivars, and to evaluate morphological and ph...

  20. Phenol accumulation in a young humic fraction following anaerobic decomposition of rice crop residues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil phenols have been implicated as inhibitors of soil nitrogen (N) cycling within many ecosystems, including irrigated lowland rice (Orzyza sativa, L.) in the Philippines. We measured soil phenol concentrations in two humic fractions at two crop growth stages in each season during a 4-year field s...

  1. Linkage Mapping of Stem Saccharification Digestibility in Rice

    PubMed Central

    Hua, Cangmei; Sun, Lili; Ali, Imran; Huang, Linli; Yu, Chunyan; Simister, Rachael; Steele-King, Clare; Gan, Yinbo; McQueen-Mason, Simon J.

    2016-01-01

    Rice is the staple food of almost half of the world population, and in excess 90% of it is grown and consumed in Asia, but the disposal of rice straw poses a problem for farmers, who often burn it in the fields, causing health and environmental problems. However, with increased focus on the development of sustainable biofuel production, rice straw has been recognized as a potential feedstock for non-food derived biofuel production. Currently, the commercial realization of rice as a biofuel feedstock is constrained by the high cost of industrial saccharification processes needed to release sugar for fermentation. This study is focused on the alteration of lignin content, and cell wall chemotypes and structures, and their effects on the saccharification potential of rice lignocellulosic biomass. A recombinant inbred lines (RILs) population derived from a cross between the lowland rice variety IR1552 and the upland rice variety Azucena with 271 molecular markers for quantitative trait SNP (QTS) analyses was used. After association analysis of 271 markers for saccharification potential, 1 locus and 4 pairs of epistatic loci were found to contribute to the enzymatic digestibility phenotype, and an inverse relationship between reducing sugar and lignin content in these recombinant inbred lines was identified. As a result of QTS analyses, several cell-wall associated candidate genes are proposed that may be useful for marker-assisted breeding and may aid breeders to produce potential high saccharification rice varieties. PMID:27415441

  2. Linkage Mapping of Stem Saccharification Digestibility in Rice.

    PubMed

    Liu, Bohan; Gómez, Leonardo D; Hua, Cangmei; Sun, Lili; Ali, Imran; Huang, Linli; Yu, Chunyan; Simister, Rachael; Steele-King, Clare; Gan, Yinbo; McQueen-Mason, Simon J

    2016-01-01

    Rice is the staple food of almost half of the world population, and in excess 90% of it is grown and consumed in Asia, but the disposal of rice straw poses a problem for farmers, who often burn it in the fields, causing health and environmental problems. However, with increased focus on the development of sustainable biofuel production, rice straw has been recognized as a potential feedstock for non-food derived biofuel production. Currently, the commercial realization of rice as a biofuel feedstock is constrained by the high cost of industrial saccharification processes needed to release sugar for fermentation. This study is focused on the alteration of lignin content, and cell wall chemotypes and structures, and their effects on the saccharification potential of rice lignocellulosic biomass. A recombinant inbred lines (RILs) population derived from a cross between the lowland rice variety IR1552 and the upland rice variety Azucena with 271 molecular markers for quantitative trait SNP (QTS) analyses was used. After association analysis of 271 markers for saccharification potential, 1 locus and 4 pairs of epistatic loci were found to contribute to the enzymatic digestibility phenotype, and an inverse relationship between reducing sugar and lignin content in these recombinant inbred lines was identified. As a result of QTS analyses, several cell-wall associated candidate genes are proposed that may be useful for marker-assisted breeding and may aid breeders to produce potential high saccharification rice varieties. PMID:27415441

  3. Groundwater flood hazards in lowland karst terrains

    NASA Astrophysics Data System (ADS)

    Naughton, Owen; McCormack, Ted

    2016-04-01

    The spatial and temporal complexity of flooding in karst terrains pose unique flood risk management challenges. Lowland karst landscapes can be particularly susceptible to groundwater flooding due to a combination of limited drainage capacity, shallow depth to groundwater and a high level of groundwater-surface water interactions. Historically the worst groundwater flooding to have occurred in the Rep. of Ireland has been centred on the Gort Lowlands, a karst catchment on the western coast of Ireland. Numerous notable flood events have been recorded throughout the 20th century, but flooding during the winters of 2009 and 2015 were the most severe on record, inundating an area in excess of 20km2 and causing widespread and prolonged disruption and damage to property and infrastructure. Effective flood risk management requires an understanding of the recharge, storage and transport mechanisms during flood conditions, but is often hampered by a lack of adequate data. Using information gathered from the 2009 and 2015 events, the main hydrological and geomorphological factors which influence flooding in this complex lowland karst groundwater system under are elucidated. Observed flood mechanisms included backwater flooding of sinks, overland flow caused by the overtopping of sink depressions, high water levels in turlough basins, and surface ponding in local epikarst watersheds. While targeted small-scale flood measures can locally reduce the flood risk associated with some mechanisms, they also have the potential to exacerbate flooding down-catchment and must be assessed in the context of overall catchment hydrology. This study addresses the need to improve our understanding of groundwater flooding in karst terrains, in order to ensure efficient flood prevention and mitigation in future and thus help achieve the aims of the EU Floods Directive.

  4. Interior River Lowland Ecoregion Summary Report

    USGS Publications Warehouse

    Karstensen, Krista A.

    2008-01-01

    ECOREGION DESCRIPTION The Interior River Lowlands ecoregion encompasses 93,200 square kilometers (km2) across southern and western Illinois, southwest Indiana, east-central Missouri, and fractions of northwest Kentucky and southeast Iowa. The ecoregion includes the confluence areas of the Mississippi, Missouri, Ohio, Illinois, and Wabash Rivers, and their tributaries. This ecoregion was formed in non-resident, non-calcareous sedimentary rock (U.S. Environmental Protection Agency, 2006). The unstratified soil deposits present north of the White River in Indiana are evidence that pre-Wisconsinan ice once covered much of the Interior River Lowlands. The geomorphic characteristics of this area also include terraced valleys filled with alluvium as well as outwash, acolian, and lacustrine deposits. Historically, agricultural land use has been a vital economic resource for this region. The drained alluvial soils are farmed for feed grains and soybeans, whereas the valley uplands also are used for forage crops, pasture, woodlots, mixed farming, and livestock (USEPA, 2006). This ecoregion provides a key component of national energy resources as it contains the second largest coal reserve in the United States, and the largest reserve of bituminous coal (Varanka and Shaver, 2007). One of the primary reasons for change in the ecoregion is urbanization.

  5. Quaternary geology of the Amazonian Lowland

    NASA Astrophysics Data System (ADS)

    Irion, Georg; Müller, Jens; Nunes de Mello, Jose; Junk, Wolfgang J.

    1995-09-01

    The Quaternary history of the Amazon lowlands is characterized by deposition of sediments of Andean provenance and by the influences of changing sea levels. Areas well above the present water tables were not reached by Pleistocene high-water stages. These areas have been intensively weathered since the Tertiary, forming hard lateritic weathering horizons. These weathering horizons are best explained by the relatively constant, humid tropical climate throughout the Quaternary. In the western Amazonian Lowland, flood plains corresponding to the different Pleistocene sea-level heights were formed. During low sea level, erosion in the drainage areas increased and the water levels of the central Amazon River system were lowered. Valleys drowned and lakes formed in the lower reaches of rivers and creeks during high sea-level stages. These lakes (ria lakes) remained in the valleys with rivers having a low sediment load. Seismic profiling (3.5 kHz) in some of these lakes clearly showed deposits of the three last periods of Quaternary high sea-level stages.

  6. Water productivity analysis for smallholder rainfed systems: A case study of Makanya catchment, Tanzania

    NASA Astrophysics Data System (ADS)

    Mutiro, J.; Makurira, H.; Senzanje, A.; Mul, M. L.

    Decreasing food security as a result of ever-increasing population, less water availability and soil degradation is common in countries in sub-Saharan Africa. While most of the developed fresh water resources are heavily committed to irrigation, about 90% of sub-Saharan populations rely solely on rainfed agriculture for their livelihoods. The majority of the population is therefore not directly benefiting from developed water resources but are, in fact, subsistence rainfed farmers. Thus, in sub-Saharan Africa, techniques which help to improve water productivity (WP) can assist in alleviating the impacts of water scarcity especially for crop production purposes. A study was conducted in the semi-arid Makanya catchment in northern Tanzania where farmers depend on rainfed subsistence farming for their livelihoods. The objective of the study was to assess the effect of improved conservation agriculture techniques on WP of a maize crop. An assessment of the current WP in rainfed and partially supplementary irrigated agriculture was made. The crop water requirement for maize in the study area was found to be 508 mm/season by using the CROPWAT model compared to total received rainfall of up to 383.86 mm per study plot during the same period. An attempt was made to separate transpiration from evapotranspiration using a transpiration meter. Results indicate that, currently, WP for maize in the catchment is low (0.18-1.33 kg m -3). Introduction of improved techniques increased WP by between 90% and 110%. Infiltration rates also increased from 6 to 26 cm/h. The conclusion from the research is that, from a purely scientific view, there is room to significantly improve the water use techniques being applied for crop productivity through improving current smallholder farming practices A clear understanding and quantification of the water partitioning processes is required to maximise productive water use by the plant as transpiration and this is directly related to biomass

  7. Aerobic rice genotypes displayed greater adaptation to water-limited cultivation and tolerance to polyethyleneglycol-6000 induced stress.

    PubMed

    Sandhu, Nitika; Jain, Sunita; Battan, K R; Jain, R K

    2012-01-01

    Water scarcity and drought have seriously threatened traditional rice cultivation practices in several parts of the world including India. In the present investigation, experiments were conducted to see if the water-efficient aerobic rice genotypes developed at UAS, Bangalore (MAS25, MAS26 and MAS109) and IRRI, Philippines (MASARB25 and MASARB868), are endowed with drought tolerance or not. A set of these aerobic and five lowland high-yielding (HKR47 and PAU201, Taraori Basmati, Pusa1121 and Pusa1460) indica rice genotypes were evaluated for: (i) yield and yield components under submerged and aerobic conditions in field, (ii) root morphology and biomass under aerobic conditions in pots in the nethouse, (iii) PEG-6000 (0, -1, -2 and -3 bar) induced drought stress at vegetative stage using a hydroponic culture system and (iv) polymorphism for three SSR markers associated with drought resistance traits. Under submerged conditions, the yield of aerobic rice genotypes declined by 13.4-20.1 % whereas under aerobic conditions the yield of lowland indica/Basmati rice varieties declined by 23-27 %. Under water-limited conditions in pots, aerobic rice genotypes had 54-73.8 % greater root length and 18-60 % higher fresh root biomass compared to lowland indica rice varieties. Notably, root length of MASARB25 was 35 % shorter than MAS25 whereas fresh and dry root biomass of MASARB25 was 10 % and 64 % greater than MAS25. The lowland indica were more sensitive to PEG-stress with a score of 5.9-7.6 for Basmati and 6.1-6.7 for non-aromatic indica rice varieties, than the aerobic rice genotypes (score 2.7-3.3). A set of three microsatellite DNA markers (RM212, RM302 and RM3825) located on chromosome 1 which has been shown to be associated with drought resistance was investigated in the present study. Two of these markers (RM212 and RM302) amplified a specific allele in all the aerobic rice genotypes which were absent in lowland indica rice genotypes. PMID:23573038

  8. Understanding the nature of methane emission from rice ecosystems as basis of mitigation strategies

    SciTech Connect

    Buendia, L.V.; Neue, H.U.; Wassmann, R.

    1996-12-31

    Methane is considered as an important Greenhouse gas and rice fields are one of the major atmospheric methane sources. The paper aims to develop sampling strategies and formulate mitigation options based on diel (day and night) and seasonal pattern of methane emission. The study was conducted in 4 countries to measure methane flux using an automatic closed chamber system. A 24-hour bihourly methane emissions were continuously obtained during the whole growing season. Daily and seasonal pattern of methane fluxes from different rice ecosystems were evaluated. Diel pattern of methane emission from irrigated rice fields, in all sites, displayed similar pattern from planting to flowering. Fluxes at 0600, 1200, and 1800 h were important components of the total diel flux. A proposed sampling frequency to accurately estimate methane emission within the growing season was designed based on the magnitude of daily flux variation. Total methane emission from different ecosystems follow the order: deepwater rice > irrigated rice > rainfed rice. Application of pig manure increased total emission by 10 times of that without manure. Green manure application increased emission by 49% of that applied only with inorganic fertilizer. Removal of floodwater at 10 DAP and 35 DAP, within a period of 4 days, inhibited production and emission of methane. The level of variation in daily methane emission and seasonal emission pattern provides useful information for accurate determination of methane fluxes. Characterization of seasonal emission pattern as to ecologies, fertilizer amendments, and water management gives an idea of where to focus mitigation strategies for sustainable rice production.

  9. Genetic diversity for mycorrhizal symbiosis and phosphate transporters in rice.

    PubMed

    Jeong, Kwanho; Mattes, Nicolas; Catausan, Sheryl; Chin, Joong Hyoun; Paszkowski, Uta; Heuer, Sigrid

    2015-11-01

    Phosphorus (P) is a major plant nutrient and developing crops with higher P-use efficiency is an important breeding goal. In this context we have conducted a comparative study of irrigated and rainfed rice varieties to assess genotypic differences in colonization with arbuscular mycorrhizal (AM) fungi and expression of different P transporter genes. Plants were grown in three different soil samples from a rice farm in the Philippines. The data show that AM symbiosis in all varieties was established after 4 weeks of growth under aerobic conditions and that, in soil derived from a rice paddy, natural AM populations recovered within 6 weeks. The analysis of AM marker genes (AM1, AM3, AM14) and P transporter genes for the direct Pi uptake (PT2, PT6) and AM-mediated pathway (PT11, PT13) were largely in agreement with the observed root AM colonization providing a useful tool for diversity studies. Interestingly, delayed AM colonization was observed in the aus-type rice varieties which might be due to their different root structure and might confer an advantage for weed competition in the field. The data further showed that P-starvation induced root growth and expression of the high-affinity P transporter PT6 was highest in the irrigated variety IR66 which also maintained grain yield under P-deficient field conditions. PMID:26466747

  10. GHG emissions from temperate lowland bog under contrasting land use: insights from the Defra Lowland Bog Project.

    NASA Astrophysics Data System (ADS)

    Worrall, Fred; dIXON, Simon

    2015-04-01

    The Defra lowland peat project was established 3 years ago in response to the estimation that while lowland peat soils represent only 15% of the area of UK peat they represented 75% of the greenhouse gas emissions. The study has considered a range of settings, including: restored raised bog; extracted bare peat; and peat soil converted for arable. The sites were instrumented to cover as complete a range of greenhouse gases as possible and this included N2O as well as fluvial carbon fluxes. This talk will review results with particular emphasis on problems of understanding fluvial carbon fluxes from lowland raised bogs where flow directions are complex.

  11. Prehistoric Earthquakes in the Puget Lowland, Washington

    NASA Astrophysics Data System (ADS)

    Sherrod, B. L.

    2005-12-01

    Coastal marsh deposits and lidar topographic data show evidence for past earthquakes on at least seven fault zones in the Puget lowland. Three major fault zones, the Seattle fault zone, Tacoma fault, and the Southern Whidbey Island fault zone (SWIFZ), cut through the heavily populated portions of central Puget Sound. Faults in four other areas, namely the Darrington-Devils Mountain fault zone, Olympia fault, the northern margin of the Olympic Mountains, and the southeastern Olympic Mountains, show that the area of active Holocene faulting extends over the entire Puget Sound lowlands. As recently as 1998, field evidence could confirm only one fault with evidence of past earthquake activity. Uplifted coastlines and surface ruptures are the field evidence for past Seattle fault earthquakes. Raised intertidal platforms along the Seattle fault zone show that regional uplift of as much as 7 meters accompanied a large earthquake about 1100 years. This earthquake also caused a tsunami, which inundated low-lying coastal areas north of Seattle. All of the lidar scarps found in the Seattle fault zone are north-side-up, opposite the vergence suggested for the Seattle fault from regional geological studies. Excavations across these scarps reveal north-dipping thrust faults that roughly follow bedding planes in bedrock and disrupt late Holocene soils. Soil stratigraphy and radiocarbon ages suggest as many as three surface-rupturing earthquakes in the past 2500 years. Lidar mapping revealed several en echelon scarps along the trace of the Tacoma fault. Existence of the Tacoma fault was previously hypothesized on the basis of large-amplitude gravity, aeromagnetic, and seismic-velocity anomalies, shallow marine seismic reflection surveys, glaciolacustrine strandlines, and coastal marsh stratigraphy. Coastal marsh deposits and scarp excavations suggest that the scarps formed during an earthquake on the Tacoma fault ~1100 years ago, possibly by folding above a buried reverse fault

  12. Root characters of Lucerne (Medicago sativa L.) under rain-fed and irrigated conditions

    NASA Astrophysics Data System (ADS)

    Raza, Amir; Moghaddam, Ali; Loiskandl, Willibald; Friedel, Jürgen K.; Himmelbauer, Margaritta; Bodner, Gernot

    2010-05-01

    In organic farming, only limited use of selected fertilizers is allowed and plants have to meet their nutritional requirements through mobilization of nutrients provided by organic amendments, crop residue input within the rotation, and released from the soil reservoir. The crop varieties used in such systems shall be efficient in nutrient and water uptake. Root length, surface area and depth distribution are important root characters that demonstrate a potential for nutrient and water uptake. Detailed information on these root characters is lacking for Lucerne, one of the most important legume crop widely used in organic farming. A study was designed to compare three lucerne cultivars from different geographical origin viz. Niva, Mohajaren and Sitel for their root characters in two different sets of experiments planted under rain-fed and irrigated conditions in 2007. The irrigated experiment should provide root traits under potential growth conditions while the rain-fed experiment should highlight root characteristics under water limited conditions. The experiments were conducted on fields of the research station Groß Enzersdorf of the University or Natural Resources and Applied Life Sciences(BOKU), Vienna, Austria. Both experiments were laid out in α-lattice design with two replicates. At the end of vegetation period, root samples were taken for every 30 cm soil profile depth till the depth of 90 cm. From each plot, one sample was taken on the row and two samples between the rows using a cylindrical auger for sampling depth of 0 - 30, 30 - 60 and 60 - 90 cm. Root samples were washed out and analyzed with WinRhizo software to determine root length, surface area, root volume and average diameter. Results revealed that cultivars under rain-fed conditions had higher root length density and surface area than under irrigated conditions. The differences in root parameters estimated for each of the Lucerne cultivars are discussed.

  13. Rainwater harvesting and management in rainfed agricultural systems in sub-Saharan Africa - A review

    NASA Astrophysics Data System (ADS)

    Biazin, Birhanu; Sterk, Geert; Temesgen, Melesse; Abdulkedir, Abdu; Stroosnijder, Leo

    Agricultural water scarcity in the predominantly rainfed agricultural system of sub-Saharan Africa (SSA) is more related to the variability of rainfall and excessive non-productive losses, than the total annual precipitation in the growing season. Less than 15% of the terrestrial precipitation takes the form of productive ‘green’ transpiration. Hence, rainwater harvesting and management (RWHM) technologies hold a significant potential for improving rainwater-use efficiency and sustaining rainfed agriculture in the region. This paper outlines the various RWHM techniques being practiced in SSA, and reviews recent research results on the performance of selected practices. So far, micro-catchment and in situ rainwater harvesting techniques are more common than rainwater irrigation techniques from macro-catchment systems. Depending on rainfall patterns and local soil characteristics, appropriate application of in situ and micro-catchment techniques could improve the soil water content of the rooting zone by up to 30%. Up to sixfold crop yields have been obtained through combinations of rainwater harvesting and fertiliser use, as compared to traditional practices. Supplemental irrigation of rainfed agriculture through rainwater harvesting not only reduces the risk of total crop failure due to dry spells, but also substantially improves water and crop productivity. Depending on the type of crop and the seasonal rainfall pattern, the application of RWHM techniques makes net profits more possible, compared to the meagre profit or net loss of existing systems. Implementation of rainwater harvesting may allow cereal-based smallholder farmers to shift to diversified crops, hence improving household food security, dietary status, and economic return. The much needed green revolution and adaptations to climate change in SSA should blend rainwater harvesting ideals with agronomic principles. More efforts are needed to improve the indigenous practices, and to disseminate best

  14. Can rainfed agriculture adapt to uncertainty in availability of water in Indus Basin?

    NASA Astrophysics Data System (ADS)

    Jutla, A.; Sen, S.

    2015-12-01

    Understanding impacts of hydrological and climatological functions under changing climate on regional floods, droughts as well as agricultural commodities remain a serious challenge in tropical agricultural basins. These "tropical agricultural basins" are regions where: (i) the understanding on hydrologic functions (such as precipitation, soil moisture, evapotranspiration, surface runoff, vegetation) are not well established; (ii) increasing population is at the convergence of rural and urban boundaries; (iii) resilience and sustainability of the water resources under different climatic conditions is unknown; and, (iv) agriculture is the primary occupation for majority of the population. More than 95% of the farmed lands in tropical regions are rainfed and 60% of total agricultural production in South Asia relying on seasonal rainfall. Tropical regions frequently suffer from unexpected droughts and sudden flash floods, resulting in massive losses in human lives and affecting regional economy. Prediction of frequency, intensity and magnitude of floods in tropical regions is still a subject of debate and research. A clear example is from the massive floods in the Eastern Indus River in July 2010 that submerged 17 million acre of fertile cropland. Yet, seasonal droughts, such as 2014 rain deficits in Indus Basin, had no effects on annual crop yields - thus creating a paradox. Large amounts of groundwater is being used to supplement water needs for crops during drought conditions, leading to oversubscription of natural aquifers. Key reason that rainfed agriculture is relying heavily on groundwater is because of the uncertainty in timing and distribution of precipitation in the tropical regions, where such data are not routinely collected as well as the basins are transnational, thus limiting sharing of data. Assessment of availability of water for agricultural purposes a serious challenge in tropical regions. This study will provide a framework for using multi

  15. Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands

    PubMed Central

    Douglas, Peter M. J.; Pagani, Mark; Canuto, Marcello A.; Brenner, Mark; Hodell, David A.; Eglinton, Timothy I.; Curtis, Jason H.

    2015-01-01

    Paleoclimate records indicate a series of severe droughts was associated with societal collapse of the Classic Maya during the Terminal Classic period (∼800–950 C.E.). Evidence for drought largely derives from the drier, less populated northern Maya Lowlands but does not explain more pronounced and earlier societal disruption in the relatively humid southern Maya Lowlands. Here we apply hydrogen and carbon isotope compositions of plant wax lipids in two lake sediment cores to assess changes in water availability and land use in both the northern and southern Maya lowlands. We show that relatively more intense drying occurred in the southern lowlands than in the northern lowlands during the Terminal Classic period, consistent with earlier and more persistent societal decline in the south. Our results also indicate a period of substantial drying in the southern Maya Lowlands from ∼200 C.E. to 500 C.E., during the Terminal Preclassic and Early Classic periods. Plant wax carbon isotope records indicate a decline in C4 plants in both lake catchments during the Early Classic period, interpreted to reflect a shift from extensive agriculture to intensive, water-conservative maize cultivation that was motivated by a drying climate. Our results imply that agricultural adaptations developed in response to earlier droughts were initially successful, but failed under the more severe droughts of the Terminal Classic period. PMID:25902508

  16. Drought, agricultural adaptation, and sociopolitical collapse in the Maya Lowlands.

    PubMed

    Douglas, Peter M J; Pagani, Mark; Canuto, Marcello A; Brenner, Mark; Hodell, David A; Eglinton, Timothy I; Curtis, Jason H

    2015-05-01

    Paleoclimate records indicate a series of severe droughts was associated with societal collapse of the Classic Maya during the Terminal Classic period (∼800-950 C.E.). Evidence for drought largely derives from the drier, less populated northern Maya Lowlands but does not explain more pronounced and earlier societal disruption in the relatively humid southern Maya Lowlands. Here we apply hydrogen and carbon isotope compositions of plant wax lipids in two lake sediment cores to assess changes in water availability and land use in both the northern and southern Maya lowlands. We show that relatively more intense drying occurred in the southern lowlands than in the northern lowlands during the Terminal Classic period, consistent with earlier and more persistent societal decline in the south. Our results also indicate a period of substantial drying in the southern Maya Lowlands from ∼200 C.E. to 500 C.E., during the Terminal Preclassic and Early Classic periods. Plant wax carbon isotope records indicate a decline in C4 plants in both lake catchments during the Early Classic period, interpreted to reflect a shift from extensive agriculture to intensive, water-conservative maize cultivation that was motivated by a drying climate. Our results imply that agricultural adaptations developed in response to earlier droughts were initially successful, but failed under the more severe droughts of the Terminal Classic period. PMID:25902508

  17. A genomic perspective on the important genetic mechanisms of upland adaptation of rice

    PubMed Central

    2014-01-01

    Background Cultivated rice consists of two important ecotypes, upland and irrigated, that have respectively adapted to either dry land or irrigated cultivation. Upland rice, widely adopted in rainfed upland areas in virtue of its little water requirement, contains abundant untapped genetic resources, such as genes for drought adaptation. With water shortage exacerbated and population expanding, the need for breeding crop varieties with drought adaptation becomes more and more urgent. However, a previous oversight in upland rice research reveals little information regarding its genetic mechanisms for upland adaption, greatly hindering progress in harnessing its genetic resources for breeding and cultivation. Results In this study, we selected 84 upland and 82 irrigated accessions from all over the world, phenotyped them under both irrigated and dry land environments, and investigated the phylogenetic relations and population structure of the upland ecotype using whole genome variation data. Further comparative analysis yields a list of differentiated genes that may account for the phenotypic and physiological differences between upland and irrigated rice. Conclusions This study represents the first genomic investigation in a large sample of upland rice, providing valuable gene list for understanding upland rice adaptation, especially drought-related adaptation, and its subsequent utilization in modern agriculture. PMID:24920279

  18. Contact urticaria from rice.

    PubMed

    Yamakawa, Y; Ohsuna, H; Aihara, M; Tsubaki, K; Ikezawa, Z

    2001-02-01

    A 30-year-old man with atopic dermatitis had had erythema and itching of the hands after washing rice in water, though he had always eaten cooked rice without problems. Handling test with water used to wash regular rice was performed on abraded hands, and produced urticarial erythema after several minutes. Applications of water used to wash allergen-reduced rice were negative for urticarial reaction. Prick test with water used to wash regular rice was +++. However prick test reaction with water used to wash allergen-reduced rice was +. Histamine-release test of regular rice-washing water was grade 3 and that of allergen-reduced rice grade 1. In immunoblotting analysis with regular rice washing water, there were no bands with this patient. These results suggest that the allergen responsible for contact urticaria in this patient might be water-soluble, heat-unstable, and not contained in allergen-reduced rice. PMID:11205411

  19. Rainwater harvesting to enhance water productivity of rainfed agriculture in the semi-arid Zimbabwe

    NASA Astrophysics Data System (ADS)

    Kahinda, Jean-marc Mwenge; Rockström, Johan; Taigbenu, Akpofure E.; Dimes, John

    Zimbabwe’s poor are predominantly located in the semi-arid regions and rely on rainfed agriculture for their subsistence. Decline in productivity, scarcity of arable land, irrigation expansion limitations, erratic rainfall and frequent dry spells, among others cause food scarcity. The challenge faced by small-scale farmers is to enhance water productivity of rainfed agriculture by mitigating intra-seasonal dry spells (ISDS) through the adoption of new technologies such as rainwater harvesting (RWH). The paper analyses the agro-hydrological functions of RWH and assesses its impacts (at field scale) on the crop yield gap as well as the Transpirational Water Productivity ( WPT). The survey in six districts of the semi-arid Zimbabwe suggests that three parameters (water source, primary use and storage capacity) can help differentiate storage-type-RWH systems from “conventional dams”. The Agricultural Production Simulator Model (APSIM) was used to simulate seven different treatments (Control, RWH, Manure, Manure + RWH, Inorganic Nitrogen and Inorganic Nitrogen + RWH) for 30 years on alfisol deep sand, assuming no fertiliser carry over effect from season to season. The combined use of inorganic fertiliser and RWH is the only treatment that closes the yield gap. Supplemental irrigation alone not only reduces the risks of complete crop failure (from 20% down to 7% on average) for all the treatments but also enhances WPT (from 1.75 kg m -3 up to 2.3 kg m -3 on average) by mitigating ISDS.

  20. Sustainable land management practices as providers of several ecosystem services under rainfed Mediterranean agroecosystems

    NASA Astrophysics Data System (ADS)

    Almagro, María; de Vente, Joris; Boix-Fayós, Carolina; García-Franco, Noelia; Melgares de Aguilar, Javier; González, David; Solé-Benet, Albert; Martínez-Mena, María

    2015-04-01

    Little is known about the multiple impacts of sustainable land management practices on soil and water conservation, carbon sequestration, mitigation of global warming, and crop yield productivity in semiarid Mediterranean agroecosystems. We hypothesized that a shift from intensive tillage to more conservative tillage management practices (reduced tillage optionally combined with green manure) leads to an improvement in soil structure and quality and will reduce soil erosion and enhance carbon sequestration in semiarid Mediterranean rainfed agroecosystems. To test the hypothesis, we assessed the effects of different tillage treatments (conventional (CT), reduced (RT), reduced tillage combined with green manure (RTG), and no tillage (NT)) on soil structure and soil water content, runoff and erosion control, soil CO2 emissions, crop yield and carbon sequestration in two semiarid agroecosystems with organic rainfed almond in the Murcia Region southeast Spain). It was found that reduction and suppression of tillage under almonds led to an increase in soil water content in both agroecosystems. Crop yields ranged from 775 to 1766 kg ha-1 between tillage 18 treatments, but we did not find a clear relation between soil water content and crop yield. RT and RTG treatments showed lower soil erosion rates and higher crop yields of almonds than under CT treatment. Overall, higher soil organic carbon contents and aggregate stability were observed under RTG treatment than under RT or CT treatment. It is concluded that conversion from CT to RTG is suitable to increase carbon inputs without enhancing soil CO2 emissions in semiarid Mediterranean agroecosystems.

  1. Programs for Watershed-Plus phase for rainfed regions in India

    NASA Astrophysics Data System (ADS)

    Ramachandran, Kausalya; Ramakrishna, Y. S.

    2006-12-01

    Watershed-based development is the strategy for sustainable growth in the vast rain-fed regions of India since 1980s to enhance agricultural production, conservation of natural resources and raising rural livelihood of farming communities. Although soil and water conservation was initially the primary objective of watershed program that saw large public investment since inception, later its focus shifted to principles of equity and enhancing rural livelihood opportunities and more recently to sustainable development since mid-1990s. At present a major emphasis under watershed program is the regeneration of degraded fragile lands in rain-fed regions. Several noteworthy watershed programs have been carried out since inception that have yielded sterling results while many others have yielded little by way of unbalanced development because of improper characterization of watersheds and poor project planning and implementation. Tools of Geomatics like satellite data, GIS and GPS besides conventional ones like field survey, topographical and cadastral maps along with traditional multi-disciplinary methods like PRA, soil and water analysis, socio-economic survey etc. provide insight into characterization of watersheds, project formulation and proper implementation of such development programs. The present paper illustrates the methodology for characterization of watersheds using the tools of Geomatics on one hand, besides exhibiting its utility for scaling-out the program benefits like sustaining higher agricultural productivity, enhancing irrigation efficiency, equity, enhanced rural livelihood opportunities, women empowerment, drought-proofing etc. during Watershed-Plus phase in the coming decades, on the other.

  2. Yield and Production Gaps in Rainfed Wheat, Barley, and Canola in Alberta.

    PubMed

    Chapagain, Tejendra; Good, Allen

    2015-01-01

    Improving crop yields are essential to meet the increasing pressure of global food demands. The loss of high quality land, the slowing in annual yield increases of major cereals, increasing fertilizer use, and the effect of this on the environment all indicate that we need to develop new strategies to increase grain yields with less impact on the environment. One strategy that could help address this concern is by narrowing the yield gaps of major crops using improved genetics and management. The objective of this study was to determine wheat (Triticum spp. L.), barley (Hordeum vulgare L.), and canola (Brassica napus L.) yields and production gaps in Alberta. We used 10 years of data (2005-2014) to understand yield variability and input efficiency at a farmers' specified level of management, and the yield potential under optimal management to suggest appropriate pathways for closing yield gaps. Significant management gaps were observed between attainable and actual yields of rainfed wheat (24%), barley (25%), and canola (30%). In addition, genetic gaps (i.e., gaps due to genetic selection) in wheat, barley, and canola were 18, 12, and 5%, respectively. Genetic selection with optimal crop management could increase yields of wheat, barley, and canola significantly, with estimated yield gains of 3.42, 1.92, and 1.65 million tons, respectively, each year under rainfed conditions in Alberta. This paper identifies yield gaps and offers suggestions to improve efficiency in crop production. PMID:26635824

  3. From rainfed agriculture to stress-avoidance irrigation: II. Sustainability, crop yield, and profitability

    NASA Astrophysics Data System (ADS)

    Vico, Giulia; Porporato, Amilcare

    2011-02-01

    The optimality of irrigation strategies may be sought with respect to a number of criteria, including water requirements, crop yield, and profitability. To explore the suitability of different demand-based irrigation strategies, we link the probabilistic description of irrigation requirements under stochastic hydro-climatic conditions, provided in a companion paper [Vico G, Porporato A. From rainfed agriculture to stress-avoidance irrigation: I. A generalized irrigation scheme with stochastic soil moisture. Adv Water Resour 2011;34(2):263-71], to crop-yield and economic analyses. Water requirements, application efficiency, and investment costs of different irrigation methods, such as surface, sprinkler and drip irrigation systems, are described via a unified conceptual and theoretical approach, which includes rainfed agriculture and stress-avoidance irrigation as extreme cases. This allows us to analyze irrigation strategies with respect to sustainability, productivity, and economic return, using the same framework, and quantify them as a function of climate, crop, and soil parameters. We apply our results to corn ( Zea mays), a food staple and biofuel source, which is currently mainly irrigated through surface systems. As our analysis shows, micro-irrigation maximizes water productivity, but more traditional solutions may be more profitable at least in some contexts.

  4. Yield and Production Gaps in Rainfed Wheat, Barley, and Canola in Alberta

    PubMed Central

    Chapagain, Tejendra; Good, Allen

    2015-01-01

    Improving crop yields are essential to meet the increasing pressure of global food demands. The loss of high quality land, the slowing in annual yield increases of major cereals, increasing fertilizer use, and the effect of this on the environment all indicate that we need to develop new strategies to increase grain yields with less impact on the environment. One strategy that could help address this concern is by narrowing the yield gaps of major crops using improved genetics and management. The objective of this study was to determine wheat (Triticum spp. L.), barley (Hordeum vulgare L.), and canola (Brassica napus L.) yields and production gaps in Alberta. We used 10 years of data (2005–2014) to understand yield variability and input efficiency at a farmers’ specified level of management, and the yield potential under optimal management to suggest appropriate pathways for closing yield gaps. Significant management gaps were observed between attainable and actual yields of rainfed wheat (24%), barley (25%), and canola (30%). In addition, genetic gaps (i.e., gaps due to genetic selection) in wheat, barley, and canola were 18, 12, and 5%, respectively. Genetic selection with optimal crop management could increase yields of wheat, barley, and canola significantly, with estimated yield gains of 3.42, 1.92, and 1.65 million tons, respectively, each year under rainfed conditions in Alberta. This paper identifies yield gaps and offers suggestions to improve efficiency in crop production. PMID:26635824

  5. Rice ( Oryza) hemoglobins

    PubMed Central

    Arredondo-Peter, Raúl; Moran, Jose F.; Sarath, Gautam

    2014-01-01

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs. PMID:25653837

  6. Territorial organization of the lowland classic maya.

    PubMed

    Marcus, J

    1973-06-01

    Thus far I have discussed ancient Maya sociopolitical structure from the upper levels of the hierarchy downward. Let me now summarize their territorial organization from the bottom upward, starting at the hamlet level (Fig. 8). The smallest unit of settlement-one usually overlooked by archeological surveys in the lowland rain forest-was probably a cluster of thatched huts occupied by a group of related families; larger clusters may have been divided into four quadrants along the lines suggested by Coe (26). Because of the long fallow period (6 to 8 years) characteristic of slash-and-burn agriculture in the Petén, these small hamlets are presumed to have changed location over the years, although they probably shifted in a somewhat circular fashion around a tertiary ceremonial-civic center for whose maintenance they were partly responsible. These tertiary centers were spaced at fairly regular intervals around secondary ceremonial-civic centers with pyramids, carved monuments, and palace-like residences. In turn, the secondary centers occurred at such regular intervals as to form hexagonal patterns around primary centers, which were still larger, with acropolises, multiple ceremonial plazas, and greater numbers of monuments. In some cases, the distance between secondary centers was roughly twice the distance between secondary and tertiary centers, creating a lattice of nested hexagonal cells. This pattern, which conforms to a Western theoretical construct, was presumably caused by factors of service function, travel, and transport. The pattern was not recognized by the Maya at all. They simply recognized that a whole series of smaller centers were dependent on a primary center and therefore mentioned its emblem glyph. Linking the centers of the various hexagons were marriage alliances between members of royal dynasties, who had no kinship ties with the farmers in the hamlets. Out of the large number of primary centers available to them, the Maya selected four as

  7. DENTAL LESIONS IN THE LOWLAND TAPIR (TAPIRUS TERRESTRIS).

    PubMed

    Tjørnelund, Karen B; Jonsson, Lena M; Kortegaard, Hanne; Arnbjerg, Jens; Nielsen, Søren S; Bertelsen, Mads F

    2015-06-01

    Dental ailments, mandibular swelling, and dentoalveolar abscesses are common in tapirs, but knowledge about prevalence or etiology of these lesions in the Tapiridae family in general, and in lowland tapirs (Tapirus terrestris) in particular, is scarce. A recent study identified resorptive lesions of unknown etiology as a common problem in the Malayan tapir (Tapirus indicus). In order to investigate the type and prevalence of dental lesions occurring in lowland tapirs, and to compare these with findings with the Malayan tapir, skulls and teeth from 46 deceased lowland tapirs were visually and radiographically examined. The specimens were divided into subpopulations according to age (juveniles, young adults, adults) and origin (free-range or captive). Dental lesions were identified in 24% (11/46) of the study population. The most common pathologic findings were complicated dental fractures with associated periapical reaction (15%) and periapical reactions of various degrees without associated detectable dental pathology (13%). All these lesions likely originated from dental trauma. As in Malayan tapirs, juveniles had significantly fewer lesions than adults. This study shows that dental lesions present frequent problems for lowland tapirs, occurring both in captive and in free-ranging individuals, and indicates that increasing age should be considered a risk factor for the development of these lesions. Notably, the predominant dental problems in lowland tapirs and Malayan tapirs are not the same. PMID:26056895

  8. Methods and future directions for paleoclimatology in the Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Douglas, Peter M. J.; Brenner, Mark; Curtis, Jason H.

    2016-03-01

    A growing body of paleoclimate data indicates that periods of severe drought affected the Maya Lowlands of southeastern Mexico and northern Central America, especially during the Terminal Classic period (ca. 800-950 CE), raising the possibility that climate change contributed to the widespread collapse of many Maya polities at that time. A broad range of paleoclimate proxy methods have been applied in the Maya Lowlands and the data derived from these methods are sometimes challenging for archeologists and other non-specialists to interpret. This paper reviews the principal methods used for paleoclimate inference in the region and the rationale for climate proxy interpretation to help researchers working in the Maya Lowlands make sense of paleoclimate datasets. In particular, we focus on analyses of speleothems and lake sediment cores. These two paleoclimate archives have been most widely applied in the Maya Lowlands and have the greatest potential to provide insights into climate change impacts on the ancient Maya. We discuss the development of chronologies for these climate archives, the proxies for past climate change found within them, and how these proxy variables are interpreted. Finally, we present strategies for improving our understanding of proxy paleoclimate data from the Maya Lowlands, including multi-proxy analyses, assessment of spatial variability in past climate change, combined analysis of climate models and proxy data, and the integration of paleoclimatology and archeology.

  9. Water for food and nature in drought-prone tropics: vapour shift in rain-fed agriculture.

    PubMed Central

    Rockström, Johan

    2003-01-01

    This paper quantifies the eco-hydrological challenge up until 2050 of producing food in balance with goods and services generated by water-dependent ecosystems in nature. Particular focus is given to the savannah zone, covering 40% of the land area in the world, where water scarcity constitutes a serious constraint to sustainable development. The analysis indicates an urgent need for a new green revolution, which focuses on upgrading rain-fed agriculture. Water requirements to produce adequate diets for humans are shown to be relatively generic irrespective of hydro-climate, amounting to a global average of 1,300 m(3) cap(-1) yr(-1). Present food production requires an estimated 6,800 km(3) yr(-1) of consumptive green water (5,000 km(3) yr(-1) in rain-fed agriculture and 1,800 km(3) yr(-1) from irrigated crops). Without considering water productivity gains, an additional 5,800 km(3) yr(-1) of water is needed to feed a growing population in 2,050 and eradicate malnutrition. It is shown that the bulk of this water will be used in rain-fed agriculture. A dynamic analysis of water productivity and management options indicates that large 'crop per drop' improvements can be achieved at the farm level. Vapour shift in favour of productive green water flow as crop transpiration could result in relative water savings of 500 km(3) yr(-1) in semi-arid rain-fed agriculture. PMID:14728794

  10. Utility of Thermal Image Sharpening for Monitoring Field-Scale Evapotranspiration over Rainfed and Irrigated Agricultural Regions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The utility of a thermal image sharpening algorithm (TsHARP) in providing fine resolution land surface temperature (LST) data to a Two-Source-Model (TSM) for mapping evapotranspiration (ET) was examined over two agricultural regions in the U.S. One site is in a rainfed corn and soybean production r...

  11. Evaluation of agronomic traits and spectral reflectance in Pacific Northwest winter wheat under rain-fed and irrigated conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The US Pacific Northwest (PNW) is a major winter wheat mega-environment characterized by a high latitude and a Mediterranean-like climate. Wheat production is predominantly rain-fed and often subject to low soil moisture. As result, discovery and introgression of drought-adaptive traits in modern cu...

  12. Wind erosion and PM10 emission affected by tillage in the world’s driest rainfed wheat region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Horse Heaven Hills of south-central Washington is the driest rainfed wheat growing region in the world. Low precipitation, high winds, poorly aggregated soils, sparse residue cover, and a tillage-based winter wheat (Triticum aestivum L.) – summer fallow (WW-SF) cropping system often combine to c...

  13. MICROBIAL CONTROL OF COLORADO POTATO BEETLE IN RAIN-FED POTATO AGROECOSYSTEMS IN THE NORTHEASTERN U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Small plot field studies in both NY and ME have demonstrated that the combination of the two microbial agents, Beauveria bassiana and Bacillus thuringiensis tenebrionis (Btt), may provide an efficacious alternative to chemical insecticides for management of Colorado potato beetles in rain-fed potato...

  14. CO2 and H2O Vapor Exchanges across Growing Seasons in Rainfed Corn-Soybean Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dynamics of CO2 (carbon dioxide) and H2O (water) vapor exchanges above corn and soybean canopies in rainfed environments provide insights into how these cropping systems respond to the combination of management and meteorological conditions. There is limited information on the C (carbon) dynamics in...

  15. Estimating evapotranspiration in different rain-fed peatlands from groundwater level changes

    NASA Astrophysics Data System (ADS)

    Dettmann, Ullrich; Maurer, Eike; Bechtold, Michel; Brümmer, Christian; Tiemeyer, Bärbel

    2014-05-01

    Biogeochemical processes in peatlands are strongly controlled by the hydrological conditions of these environments. One of the key parameters controlling the water balance is the evapotranspiration, which can be calculated e.g. by the FAO crop reference evapotranspiration or the Penman-Monteith equation as a function of atmospheric conditions and plant specific parameters. These parameters are well investigated for agricultural crops and forests but poorly for most peatland vegetation types. Direct measurement of the evapotranspiration is possible with weighing lysimeters or the eddy-covariance technique, but expensive and time consuming. In many peatlands and riparian areas groundwater table changes are characterized by diurnal fluctuations (daytime decline, night-time recovery) caused by the evapotranspiration and groundwater recharge. White introduced 1932 a method to calculate the evapotranspiration from these diurnal fluctuations. In contrast to traditional evapotranspiration models only a small number of variables need to be measured (groundwater level changes, possibly precipitation) or calculated (specific yield). Over the last decades, several studies and modifications of the White method have been published. Several authors showed the applicability of the method for riparian areas and fens, but this relies on the assumption of a constant recharge over the whole day. As there is no groundwater inflow at rain-fed peatlands, recovery during night-time can only result from redistribution in the soil profile or from lateral flow processes within the peatland. Thus, approaches to calculate evapotranspiration from diurnal groundwater fluctuations used to date need to be adapted. Based on 50 hydrographs measured in 6 rain-fed peatlands in Germany characterized by different soil properties, land use and vegetation, we systematically analyzed diurnal patterns of the groundwater levels. These patterns were spatially and temporally very variable. At some sites, the

  16. A global map of rainfed cropland areas (GMRCA) at the end of last millennium using remote sensing

    USGS Publications Warehouse

    Biradar, C.M.; Thenkabail, P.S.; Noojipady, P.; Li, Y.; Dheeravath, V.; Turral, H.; Velpuri, M.; Gumma, M.K.; Gangalakunta, O.R.P.; Cai, X.L.; Xiao, X.; Schull, M.A.; Alankara, R.D.; Gunasinghe, S.; Mohideen, S.

    2009-01-01

    The overarching goal of this study was to produce a global map of rainfed cropland areas (GMRCA) and calculate country-by-country rainfed area statistics using remote sensing data. A suite of spatial datasets, methods and protocols for mapping GMRCA were described. These consist of: (a) data fusion and composition of multi-resolution time-series mega-file data-cube (MFDC), (b) image segmentation based on precipitation, temperature, and elevation zones, (c) spectral correlation similarity (SCS), (d) protocols for class identification and labeling through uses of SCS R2-values, bi-spectral plots, space-time spiral curves (ST-SCs), rich source of field-plot data, and zoom-in-views of Google Earth (GE), and (e) techniques for resolving mixed classes by decision tree algorithms, and spatial modeling. The outcome was a 9-class GMRCA from which country-by-country rainfed area statistics were computed for the end of the last millennium. The global rainfed cropland area estimate from the GMRCA 9-class map was 1.13 billion hectares (Bha). The total global cropland areas (rainfed plus irrigated) was 1.53 Bha which was close to national statistics compiled by FAOSTAT (1.51 Bha). The accuracies and errors of GMRCA were assessed using field-plot and Google Earth data points. The accuracy varied between 92 and 98% with kappa value of about 0.76, errors of omission of 2-8%, and the errors of commission of 19-36%. ?? 2008 Elsevier B.V.

  17. Hydroecological impacts of climate change modelled for a lowland UK wetland

    NASA Astrophysics Data System (ADS)

    House, Andrew; Acreman, Mike; Sorensen, James; Thompson, Julian

    2015-04-01

    Conservation management of wetlands often rests on modifying hydrological functions to establish or maintain desired flora and fauna. Hence the ability to predict the impacts of climate change is highly beneficial. Here, the physically based, distributed model MIKE SHE was used to simulate hydrology for the Lambourn Observatory at Boxford, UK. This comprises a 10 ha lowland riparian wetland protected for conservation, where the degree of variability in the peat, gravel and chalk geology has clouded hydrological understanding. Notably, a weathered layer on the chalk aquifer surface seals it from overlying deposits, yet is highly spatially heterogeneous. Long-term monitoring yielded observations of groundwater and surface water levels for model calibration and validation. Simulated results were consistent with observed data and reproduced the effects of seasonal fluctuations and in-channel macrophyte growth. The adjacent river and subsidiary channel were found to act as head boundaries, exerting a general control on water levels across the site. Discrete areas of groundwater upwellings caused raised water levels at distinct locations within the wetland. These were concurrent to regions where the weathered chalk layer is absent. To assess impacts of climate change, outputs from the UK Climate Projections 2009 ensemble of global climate models for the 2080s are used to obtain monthly percentage changes in climate variables. Changes in groundwater levels were taken from a regional model of the Chalk aquifer. Values of precipitation and evapotranspiration were seen to increase, whilst groundwater levels decreased, resulting in the greater dominance of precipitation. The discrete areas of groundwater upwelling were seen to diminish or disappear. Simulated water levels were linked to specific requirements of wetland plants using water table depth zone diagrams. Increasing depth of winter and summer groundwater levels leads to a loss of Glyceria maxima and Phragmites

  18. Deforestation scenarios for the Bolivian lowlands.

    PubMed

    Tejada, Graciela; Dalla-Nora, Eloi; Cordoba, Diana; Lafortezza, Raffaele; Ovando, Alex; Assis, Talita; Aguiar, Ana Paula

    2016-01-01

    all Bolivian lowlands reaching 37,944,434 ha and leaves small forest patches in a few PAs. These deforestation scenarios are not meant to predict the future but to show how current and future decisions carried out by the neo-extractivist practices of MAS government could affect deforestation and carbon emission trends. In this perspective, recognizing land use systems as open and dynamic systems is a central challenge in designing efficient land use policies and managing a transition towards sustainable land use. PMID:26604078

  19. Exchange of nitrous oxide within the Hudson Bay lowland

    SciTech Connect

    Schiller, C.L.; Hastie, D.R.

    1994-01-20

    Static chamber and gas exchange techniques were used to measure nitrous oxide fluxes from soil and water at five sites within the Hudson Bay Lowland as part of the Northern Wetland Study. Episodic and diffusive mechanisms are indicated as likely sources for nitrous oxide emissions. Episodic emissions could not be detected by the gas exchange technique, therefore, it is not an appropriate measurement method for wetland water emission rate determination. LANDSAT-Thermatic Mapper imagery was used to scale nitrous oxide emissions on a regional scale over the entire Hudson Bay Lowland area.

  20. AmeriFlux US-Ne3 Mead - rainfed maize-soybean rotation site

    DOE Data Explorer

    Suyker, Andy [University of Nebraska - Lincoln

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-Ne3 Mead - rainfed maize-soybean rotation site. Site Description - The study site is one of three fields (all located within 1.6 km of each other) at the University of Nebraska Agricultural Research and Development Center near Mead, Nebraska. While the other two sites are equipped with irrigation systems, this site relies on rainfall. A tillage operation (disking) was done just prior to the 2001 planting to homogenize the top 0.1 m of soil, incorporate P and K fertilizers, as well as previously accumulated surface residues. Since initiation of the study in 2001, this site has been under no-till management.

  1. A Decision Support System for Climate Change Adaptation in Rainfed Sectors of Agriculture for Central Europe

    NASA Astrophysics Data System (ADS)

    Mátyás, Csaba; Berki, Imre; Drüszler, Áron; Eredics, Attila; Gálos, Borbála; Illés, Gábor; Móricz, Norbert; Rasztovits, Ervin; Czimber, Kornél

    2013-04-01

    • Background and aims: Rainfed sectors of agriculture such as nature-close forestry, non-irrigated agriculture and animal husbandry on nature-close pastures are threatened by projected climate change especially in low-elevation regions in Southeast Europe, where precipitation is the limiting factor of production and ecosystem stability. Therefore the importance of complex, long term management planning and of land use optimization is increasing. The aim of the Decision Support System under development is to raise awareness and initiate preparation for frequency increase of extreme events, disasters and economic losses in the mentioned sectors. • Services provided: The Decision Support System provides GIS-supported information about the most important regional and local risks and mitigation options regarding climate change impacts, projected for reference periods until 2100 (e.g. land cover/use and expectable changes, potential production, water and carbon cycle, biodiversity and other ecosystem services, potential pests and diseases, tolerance limits etc.). The projections are referring first of all on biological production (natural produce), but the System includes also social and economic consequences. • Methods: In the raster based system, the latest image processing technology is used. We apply fuzzy membership functions, Support Vector Machine and Maximum Likelihood classifier. The System is developed in the first step for a reference area in SW Hungary (Zala county). • Novelty: The coherent, fine-scale regional system integrates the basic information about present and projected climates, extremes, hydrology and soil conditions and expected production potential for three sectors of agriculture as options for land use and conservation. • Funding: The development of the Decision Support System "Agrárklíma" is supported by TÁMOP-4.2.2.A-11/1/KONV and 4.2.2.B-10/1-2010-0018 "Talentum" joint EU-national research projects. Keywords: climate change

  2. Potential impact of climate change on rainfed agriculture of a semi-arid basin in Jordan

    NASA Astrophysics Data System (ADS)

    Al-Bakri, Jawad; Suleiman, Ayman; Abdulla, Fayez; Ayad, Jamal

    Rainfed agriculture in Jordan is one of the most vulnerable sectors to climate change, as the available water and land resources are limited and most of the country’s land is arid. In this study, a crop simulation model (DSSAT) was used to assess the impact of different climate change scenarios on rainfed wheat and barley in the Yarmouk basin in Jordan. Analysis of observed crop data showed differences between cultivated and harvested areas for both crops in the study area with variations among years. Results from DSSAT model for years showed that it was able to capture the trend of yield over the years realistically well. The model predicted an average yield of wheat of 1176 kg ha -1, which was close to the average (1173 kg ha -1) obtained from the data of department of statistics (DOS), and an average predicted yield of barley was 927 kg ha -1 while the DOS average was 922 kg ha -1, with higher RMSE for barley (476 kg ha -1) than for wheat (319 kg ha -1). Results for predicting future yield of both crops showed that the responses of wheat and barley were different under different climate change scenarios. The reduction of rainfall by 10-20% reduced the expected yield by 4-8% for barley and 10-20% for wheat, respectively. The increase in rainfall by 10-20% increased the expected yield by 3-5% for barley and 9-18% for wheat, respectively. The increase of air temperature by 1, 2, 3 and 4 °C resulted in deviation from expected yield by -14%, -28%, -38% and -46% for barley and -17%, +4%, +43% and +113% for wheat, respectively. These results indicated that barley would be more negatively affected by the climate change scenarios and therefore adaptation plans should prioritize the arid areas cultivated with this crop.

  3. Spatiotemporal rain-fed wheat modeling using a land surface model and a crop stress index

    NASA Astrophysics Data System (ADS)

    Ghazanfari, Sadegh; Alizadeh, Amin; Faridhosseini, Alireza; Pande, Saket

    2013-04-01

    Rain-fed wheat yield estimation is an important issue in crop modeling. Regression and empirical equations are generally used to estimate wheat yields based on effective factors. These equations also need to be calibrated for each study area. Further, employing inaccurate inputs increases prediction uncertainty. Precipitation is the most important input for the rain-fed crops modeling and often interpolated data for areas without rain gauges is used. In this study, the outputs of two precipitation estimation models based on remotely sensed data, PERSIANN and TRMM, are used as alternatives to interpolated data. Results show that the precipitation estimation models outputs are more correlated with observed data than the interpolated precipitation data. Correlation coefficient at a meteorological station in Iran based on Kendall's test is 0.8 for PERSIANN while it is 0.4 and 0.5 for two interpolation methods, Inverse Distance Weighting and Kriging respectively. A simple evaporation/transpiration scheme (SETS), which is a distributed land surface model, has also been developed to estimate actual evaporation and transpiration. Finally a new crop stress index based on actual by potential transpiration (APT) is introduced to model crop yield by using SETS outputs at field scale. Results show that modeling crop yields based on APT, when SETS is forced by local field datasets at 10 sites, can estimate yields reasonably well when compared with other methods. The correlation coefficient with the observed yield data is at least 0.5 and the LSD (Least Significant Difference) test show no significant difference between measured and modeled yields at all sites. Our estimation method performs better than other methods in estimating yields based on the yields predicted by the other methods at the same sites.

  4. Comparison of winter wheat yield sensitivity to climate variables under irrigated and rain-fed conditions

    NASA Astrophysics Data System (ADS)

    Xiao, Dengpan; Shen, Yanjun; Zhang, He; Moiwo, Juana P.; Qi, Yongqing; Wang, Rende; Pei, Hongwei; Zhang, Yucui; Shen, Huitao

    2016-09-01

    Crop simulation models provide alternative, less time-consuming, and cost-effective means of determining the sensitivity of crop yield to climate change. In this study, two dynamic mechanistic models, CERES (Crop Environment Resource Synthesis) and APSIM (Agricultural Production Systems Simulator), were used to simulate the yield of wheat ( Triticum aestivum L.) under well irrigated (CFG) and rain-fed (YY) conditions in relation to different climate variables in the North China Plain (NCP). The study tested winter wheat yield sensitivity to different levels of temperature, radiation, precipitation, and atmospheric carbon dioxide (CO2) concentration under CFG and YY conditions at Luancheng Agro-ecosystem Experimental Stations in the NCP. The results from the CERES and APSIM wheat crop models were largely consistent and suggested that changes in climate variables influenced wheat grain yield in the NCP. There was also significant variation in the sensitivity of winter wheat yield to climate variables under different water (CFG and YY) conditions. While a temperature increase of 2°C was the threshold beyond which temperature negatively influenced wheat yield under CFG, a temperature rise exceeding 1°C decreased winter wheat grain yield under YY. A decrease in solar radiation decreased wheat grain yield under both CFG and YY conditions. Although the sensitivity of winter wheat yield to precipitation was small under the CFG, yield decreased significantly with decreasing precipitation under the rainfed YY treatment. The results also suggest that wheat yield under CFG linearly increased by ≈3.5% per 60 ppm (parts per million) increase in CO2 concentration from 380 to 560 ppm, and yield under YY increased linearly by ≈7.0% for the same increase in CO2 concentration.

  5. Asiatic cotton can generate similar economic benefits to Bt cotton under rainfed conditions.

    PubMed

    Romeu-Dalmau, Carla; Bonsall, Michael B; Willis, Katherine J; Dolan, Liam

    2015-01-01

    American cotton (Gossypium hirsutum L.), transformed with Bacillus thuringiensis Cry genes (Bt G. hirsutum) that confer resistance to lepidopteran pests, is extensively cultivated worldwide. In India, transgenic Bt G. hirsutum was commercially released in 2002 and by 2014 95% of farmers had adopted Bt G. hirsutum(1). The economic benefits of Bt G. hirsutum over non-Bt G. hirsutum are well documented and include increase in yields, increase in farmers' net revenue and reduction in pesticide application against lepidopteran pests(2-9). However, it is unclear to what extent irrigation influences the performance of Bt G. hirsutum on smallholder farming in India, and if, in the absence of irrigation, growing Bt G. hirsutum provides greater economic benefits for Indian smallholder farmers compared with growing the Asiatic cotton Gossypium arboreum L. Here, we compare the economic impact of growing Bt G. hirsutum with growing G. arboreum under rainfed conditions in the Indian state of Maharashtra, and show that G. arboreum can generate similar net revenue, and thus similar economic benefits for smallholder farmers compared with growing Bt G. hirsutum. We also compare the economic impact of growing Bt G. hirsutum under rainfed conditions with growing Bt G. hirsutum under irrigated conditions and show that even though Bt G. hirsutum yields increase with irrigation, the net revenue does not significantly increase because farmers using irrigation spend significantly more than farmers growing Bt G. hirsutum without irrigation. We conclude that our data provide a broader insight into how socio-economic data needs to be incorporated into agro-ecological data when planning strategies to improve cotton farming in India. PMID:27250007

  6. Comparison of winter wheat yield sensitivity to climate variables under irrigated and rain-fed conditions

    NASA Astrophysics Data System (ADS)

    Xiao, Dengpan; Shen, Yanjun; Zhang, He; Moiwo, Juana P.; Qi, Yongqing; Wang, Rende; Pei, Hongwei; Zhang, Yucui; Shen, Huitao

    2015-11-01

    Crop simulation models provide alternative, less time-consuming, and cost-effective means of determining the sensitivity of crop yield to climate change. In this study, two dynamic mechanistic models, CERES (Crop Environment Resource Synthesis) and APSIM (Agricultural Production Systems Simulator), were used to simulate the yield of wheat (Triticum aestivum L.) under well irrigated (CFG) and rain-fed (YY) conditions in relation to different climate variables in the North China Plain (NCP). The study tested winter wheat yield sensitivity to different levels of temperature, radiation, precipitation, and atmospheric carbon dioxide (CO2) concentration under CFG and YY conditions at Luancheng Agro-ecosystem Experimental Stations in the NCP. The results from the CERES and APSIM wheat crop models were largely consistent and suggested that changes in climate variables influenced wheat grain yield in the NCP. There was also significant variation in the sensitivity of winter wheat yield to climate variables under different water (CFG and YY) conditions. While a temperature increase of 2°C was the threshold beyond which temperature negatively influenced wheat yield under CFG, a temperature rise exceeding 1°C decreased winter wheat grain yield under YY. A decrease in solar radiation decreased wheat grain yield under both CFG and YY conditions. Although the sensitivity of winter wheat yield to precipitation was small under the CFG, yield decreased significantly with decreasing precipitation under the rainfed YY treatment. The results also suggest that wheat yield under CFG linearly increased by ≈3.5% per 60 ppm (parts per million) increase in CO2 concentration from 380 to 560 ppm, and yield under YY increased linearly by ≈7.0% for the same increase in CO2 concentration.

  7. Dynamics of Soil Heat Flux in Lowland Area: Estimating the Soil Thermal Conductivy

    NASA Astrophysics Data System (ADS)

    Zimmer, T.; Silveira, M. V.; Roberti, D. R.

    2013-05-01

    In this work, it is shown soil thermal conductivity estimates in a flooded irrigated rice culture located at the Paraíso do Sul city for two distinct periods. The thermal conductivity is higher when the heat storage is higher and the soil surface temperature is lower. The soil thermal conductivity is also dependant on the soil texture, porosity and moisture. Therefore, it varies from soil to soil and in the same soil, depending on its soil moisture. For approximately 80% of its growing season, lowland flooded irrigated rice ecosystems stay under a 5 - 10 cm water layer. It affects the partitioning of the energy and water balance components. Furthermore this planting technique differs substantially from any other upland non-irrigated or irrigated crop ecosystems where the majority of observational studies have been conducted. In the present work, the dynamic of soil heat flux (G) is analyzed and the soil thermal conductivity (Ks) is estimated using experimental data form soil heat flux and soil temperature in a rice paddy farm in a subtropical location in Southern Brazil. In this region, rice grows once a year at river lowlands and wetlands while the ground is kept bare during the remaining of the year. The soil type is Planossolo Hidromórfico Distrófico, characterized as a mix between sandy and clay soil. The soil heat flux (G) was experimentally estimated with the sensor Hukseflux (HFP01SC-L) at 7 cm bellow the soil surface. The soil temperature at 5 cm and 10 cm was experimentally estimated using the sensor STP01. The experimental soil heat flux was compared with estimated soil heat flux by two forms: (1) using a know Ks from literature for this type of soil in saturated conditions (Ks=1.58); (2) using Ks estimated using the inversion of the equation Qg=-ks* ((T10-T5)/ (Z2-Z1)), where T10 and T5 are the temperature in 10 and 5 cm above the soil and Z2-Z1 is the difference between the positions in temperature measurement. The study period for estimating the Ks

  8. Agro-ecological variations of sheath rot disease of rice caused by Sarocladium oryzae and DNA fingerprinting of the pathogen's population structure.

    PubMed

    Tajul Islam Chowdhury, M; Salim Mian, M; Taher Mia, M A; Rafii, M Y; Latif, M A

    2015-01-01

    To examine the impact of regional and seasonal variations on the incidence and severity of sheath rot, a major seed-borne disease of rice caused by Sarocladium oryzae, data on incidence and severity were collected from 27 selected fields in the Gazipur, Rangpur, Bogra, Chittagong, Comilla, Gopalgonj, Jessore, Manikgonj, and Bhola districts of Bangladesh in rain-fed and irrigated conditions. Cultural variability of 29 pathogen isolates obtained from 8 different locations was studied on potato dextrose agar (PDA) and genetic variability was determined by DNA fingerprinting using variable number tandem repeat-polymerase chain reaction markers. Overall, disease incidence and severity were higher in irrigated rice. Disease incidence and severity were highest in the Bhola district in rain-fed rice and lowest in irrigated rice. Mycelial growth of 29 representative isolates was found to vary on PDA and the isolates were divided into 6 groups. The range of the overall size of conidia of the selected isolates was 2.40-7.20 x 1.20-2.40 μm. Analysis of the DNA fingerprint types of the 29 isolates of S. oryzae, obtained from the amplification reactions, revealed 10 fingerprinting types (FPTs) that were 80% similar. FPT-1 was the largest group and included 13 isolates (44.8%), while FPT-2 was the third largest group and included 3 isolates. Each of FPT-3, 4, 5, and 6 included only 1 isolate. We observed no relationship between cultural and genetic groupings. PMID:26782461

  9. Natural hybrids and gene flow between upland and lowland switchgrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Switchgrass (Panicum virgatum L.) is a perennial grass native to the North American tallgrass prairie and savanna habitats and is broadly adapted to the central and eastern USA. Upland and lowland ecotypes represent the two major taxa within switchgrass, which have distinct, but overlapping distribu...

  10. An Indian Federation in Lowland Ecuador. IWGIA Document 28.

    ERIC Educational Resources Information Center

    Salazar, Ernesto

    Official involvement of the Ecuadorian government with colonization of the southern lowlands, lands traditionally belonging to the Shuar Indians, began in the early 60's when the CREA (Centro de Reconversion Economica del Azuay) was created to provide assistance to white settlers. Until that time, the Shuar lands had been dominated by the Salesian…

  11. Retroperitoneal abscesses in two western lowland gorillas (Gorilla gorilla gorilla).

    PubMed

    Hahn, Alicia; D'Agostino, Jennifer; Cole, Gretchen A; Raines, Jan

    2014-03-01

    This report describes two cases of retroperitoneal abscesses in female western lowland gorillas (Gorilla gorilla gorilla). Clinical symptoms included perivulvar discharge, lameness, hindlimb paresis, and general malaise. Retroperitoneal abscesses should be considered as part of a complete differential list in female gorillas with similar clinical signs. PMID:24712182

  12. Rice Production and Marketing.

    ERIC Educational Resources Information Center

    Briers, Gary; Lee, Jasper S.

    This guide contains lesson plans for use in secondary programs of agricultural education in geographical areas in which rice is produced. Six units and 13 problem areas are organized into teaching plans that cover the broad nature of rice production. The six units are: (1) determining the importance and history of rice production; (2) determining…

  13. Methane emission from Indonesian rice fields with special references to the effects of yearly and seasonal variations, rice variety, soil type and water management

    NASA Astrophysics Data System (ADS)

    Lumbanraja, Jamalam; Ghani Nugroho, Sutopo; Niswati, Ainin; Sabe Ardjasa, Wayan; Subadiyasa, Netera; Arya, Nyoman; Haraguchi, Hiroki; Kimura, Makoto

    1998-10-01

    Total amounts of CH4 emission from a Sumatra rice field were in the ranges 29·5-48·2 and 43·0-64·6 g CH4 m-2 season-1 for the plots with chemical fertilizer (CF-plot) and those with rice straw application (RS-plot), respectively. Nearly the same amounts of CH4 were emitted in the first and second half of the growth period, irrespective of rice straw application. The increase in the amounts of CH4 emission by rice straw application were from 1·3 to 1·6 times. There was no significant difference in the mean CH4 emission rates between rainy and dry seasons. Rain-fed conditions decreased the CH4 emission by 27-37% compared with continuously flooded conditions. Total amounts of CH4 emission from a rice field growing eight popular modern rice varieties in Indonesia were in the ranges 32·6-41·7 and 51·3-64·6 g CH4 m-2 season-1 for CF- and RS-plots, respectively. Total amounts of CH4 emission from four Sumatra rice fields with different soil types (a Typic Paleudult, a Typic Sulfaquent, a Typic Tropohumult and a Typic Tropopsament) were in the range 22·1 (a Typic Sulfaquent) to 53·4 (a Typic Tropohumult) g CH4 m-2 season-1rice fields with soils of volcanic ash origin were very low; 3·5-7·7 and 5·3-14·3 g CHrice fields showed the specific productivity of grain production, and CHrice fields of volcanic ash origin to 83 and 121 g CHrice field for CF- and RS-plots, respectively. Water management was also an important factor in decreasing the CH

  14. From Early Domesticated Rice of the Middle Yangtze Basin to Millet, Rice and Wheat Agriculture: Archaeobotanical Macro-Remains from Baligang, Nanyang Basin, Central China (6700-500 BC).

    PubMed

    Deng, Zhenhua; Qin, Ling; Gao, Yu; Weisskopf, Alison Ruth; Zhang, Chi; Fuller, Dorian Q

    2015-01-01

    Baligang is a Neolithic site on a northern tributary of the middle Yangtze and provides a long archaeobotanical sequence from the Seventh Millennium BC upto the First Millennium BC. It provides evidence for developments in rice and millet agriculture influenced by shifting cultural affiliation with the north (Yangshao and Longshan) and south (Qujialing and Shijiahe) between 4300 and 1800 BC. This paper reports on plant macro-remains (seeds), from systematic flotation of 123 samples (1700 litres), producing more than 10,000 identifiable remains. The earliest Pre-Yangshao occupation of the sites provide evidence for cultivation of rice (Oryza sativa) between 6300-6700 BC. This rice appears already domesticated in on the basis of a dominance of non-shattering spikelet bases. However, in terms of grain size changes has not yet finished, as grains are still thinner than more recent domesaticated rice and are closer in grain shape to wild rices. This early rice was cultivated alongside collection of wild staple foods, especially acorns (Quercus/Lithicarpus sensu lato). In later periods the sites has evidence for mixed farming of both rice and millets (Setaria italica and Panicum miliaceum). Soybean appears on the site in the Shijiahe period (ca.2500 BC) and wheat (Triticum cf. aestivum) in the Late Longshan levels (2200-1800 BC). Weed flora suggests an intensification of rice agriculture over time with increasing evidence of wetland weeds. We interpret these data as indicating early opportunistic cultivation of alluvial floodplains and some rainfed rice, developing into more systematic and probably irrigated cultivation starting in the Yangshao period, which intensified in the Qujialing and Shijiahe period, before a shift back to an emphasis on millets with the Late Longshan cultural influence from the north. PMID:26460975

  15. From Early Domesticated Rice of the Middle Yangtze Basin to Millet, Rice and Wheat Agriculture: Archaeobotanical Macro-Remains from Baligang, Nanyang Basin, Central China (6700–500 BC)

    PubMed Central

    Deng, Zhenhua; Qin, Ling; Gao, Yu; Weisskopf, Alison Ruth; Zhang, Chi; Fuller, Dorian Q.

    2015-01-01

    Baligang is a Neolithic site on a northern tributary of the middle Yangtze and provides a long archaeobotanical sequence from the Seventh Millennium BC upto the First Millennium BC. It provides evidence for developments in rice and millet agriculture influenced by shifting cultural affiliation with the north (Yangshao and Longshan) and south (Qujialing and Shijiahe) between 4300 and 1800 BC. This paper reports on plant macro-remains (seeds), from systematic flotation of 123 samples (1700 litres), producing more than 10,000 identifiable remains. The earliest Pre-Yangshao occupation of the sites provide evidence for cultivation of rice (Oryza sativa) between 6300–6700 BC. This rice appears already domesticated in on the basis of a dominance of non-shattering spikelet bases. However, in terms of grain size changes has not yet finished, as grains are still thinner than more recent domesaticated rice and are closer in grain shape to wild rices. This early rice was cultivated alongside collection of wild staple foods, especially acorns (Quercus/Lithicarpus sensu lato). In later periods the sites has evidence for mixed farming of both rice and millets (Setaria italica and Panicum miliaceum). Soybean appears on the site in the Shijiahe period (ca.2500 BC) and wheat (Triticum cf. aestivum) in the Late Longshan levels (2200–1800 BC). Weed flora suggests an intensification of rice agriculture over time with increasing evidence of wetland weeds. We interpret these data as indicating early opportunistic cultivation of alluvial floodplains and some rainfed rice, developing into more systematic and probably irrigated cultivation starting in the Yangshao period, which intensified in the Qujialing and Shijiahe period, before a shift back to an emphasis on millets with the Late Longshan cultural influence from the north. PMID:26460975

  16. A 2,000-year reconstruction of the rain-fed maize agricultural niche in the US Southwest

    NASA Astrophysics Data System (ADS)

    Bocinsky, R. Kyle; Kohler, Timothy A.

    2014-12-01

    Humans experience, adapt to and influence climate at local scales. Paleoclimate research, however, tends to focus on continental, hemispheric or global scales, making it difficult for archaeologists and paleoecologists to study local effects. Here we introduce a method for high-frequency, local climate-field reconstruction from tree-rings. We reconstruct the rain-fed maize agricultural niche in two regions of the southwestern United States with dense populations of prehispanic farmers. Niche size and stability are highly variable within and between the regions. Prehispanic rain-fed maize farmers tended to live in agricultural refugia—areas most reliably in the niche. The timing and trajectory of the famous thirteenth century Pueblo migration can be understood in terms of relative niche size and stability. Local reconstructions like these illuminate the spectrum of strategies past humans used to adapt to climate change by recasting climate into the distributions of resources on which they depended.

  17. A 2,000-year reconstruction of the rain-fed maize agricultural niche in the US Southwest.

    PubMed

    Bocinsky, R Kyle; Kohler, Timothy A

    2014-01-01

    Humans experience, adapt to and influence climate at local scales. Paleoclimate research, however, tends to focus on continental, hemispheric or global scales, making it difficult for archaeologists and paleoecologists to study local effects. Here we introduce a method for high-frequency, local climate-field reconstruction from tree-rings. We reconstruct the rain-fed maize agricultural niche in two regions of the southwestern United States with dense populations of prehispanic farmers. Niche size and stability are highly variable within and between the regions. Prehispanic rain-fed maize farmers tended to live in agricultural refugia--areas most reliably in the niche. The timing and trajectory of the famous thirteenth century Pueblo migration can be understood in terms of relative niche size and stability. Local reconstructions like these illuminate the spectrum of strategies past humans used to adapt to climate change by recasting climate into the distributions of resources on which they depended. PMID:25472022

  18. 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.

  19. Effect of rainfed cereal crops on the wind erosion in the Algerian steppe (Case study in Laghouat)

    NASA Astrophysics Data System (ADS)

    Houyou, Zohra; Bielders, Charles L.; Boutmedjet, Ahmed; Dellal, Abdelkader

    2014-05-01

    Summary The Algerian steppe 20 million ha, bounded on the north by the 400 mm isohyets and south by the 100 mm isohyets. This territory is subject to increasing human pressure. For several decades, this area has been home to rainfed cereal cropping subjecting soils to a strong fragmentation during seedbed preparation, thereby facilitating the degradation of soil by wind erosion. This study was conducted within the agricultural area of Mokrane (Laghouat), a region of the Algerian steppe. In 2009 and 2010, sediment mass flux densities were measured using BSNE sand-traps on a plot of 1.35 ha cropped with rainfed barley (Hordeum vulgare). A weather station equipped with anemometers, a wind vane and a saltiphone was used to acquire the data needed to characterize erosive events. The results show that in Laghouat sandstorms can last for several days. However, the actual erosive periods were highly variable in terms of duration, ranging from a few minutes to several hours interspersed with calm periods. Erosive winds originated from the west and north. The average wind speeds during saltation were between 6.2 and 7.3 m/s. The threshold velocity had low seasonality and varied between 5.7 m/s and 7.6 m/s. The measured mass balances were negative and fluctuated between -74.5 t/ha -2.8 t/ha depending on the measurement periods. The total soil loss measured over a period of two years confirms that rainfed cultivation induces severe degradation of soil by wind erosion in the Algerian steppe and should be discouraged. Keywords: Wind erosion, rainfed cereal cropping, steppe, Algeria.

  20. Predicting economic losses from the continued spread of the Mexican rice borer (Lepidoptera: Crambidae).

    PubMed

    Reay-Jones, F P F; Wilson, L T; Reagan, T E; Legendre, B L; Way, M O

    2008-04-01

    The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is an invasive species that originated from Mexico, and it is threatening to cause major economic losses to sugarcane, Saccharum spp., and rice, Oryza sativa L., industries in Louisiana. The insect is expected to reach sugarcane and rice production areas in Louisiana by 2008, and infest all of Louisiana sugarcane and rice industries by 2035. When all sugarcane in Louisiana becomes infested, annual yield losses of $220 million would be expected for a cultivar of comparable susceptibility to LCP 85-384 (assuming this cultivar is planted on 100% of the production area). This also assumes the use of the current practice of rainfed production and one application of insecticide, which is presently used by farmers in Louisiana. Irrigation with 30 cm of water is predicted to reduce estimated losses by 29%, whereas four applications of a biorational insecticide such as tebufenozide are expected to reduce the loss in revenue by 53%. The use of the resistant 'HoCP 85-845' would reduce the projected loss in revenue by 24%. Combining all three management tactics on sugarcane, anticipated net loss in revenue would decrease by 66%. The rice industry in Louisiana is projected to suffer from a loss in revenue of $45 million when the entire state is infested. A 77% reduction in loss in revenue is expected with one application of lambda-cyhalothrin. A quarantine on east Texas sugarcane is estimated to save the Louisiana industry between $1.1 billion and $3.2 billion (depending on management) during the time needed for the insect to fully invade the state's sugarcane and rice producing area by natural migration rather than by accidental introduction. The rapid deployment of appropriate management tactics will have a key role in reducing the anticipated economic impact of E. loftini once it becomes a pest in Louisiana sugarcane and rice. PMID:18459384

  1. Thermal and visible remote sensing for estimation of evapotranspiration of rainfed agrosystems and its impact on groundwater in SE Australia

    NASA Astrophysics Data System (ADS)

    Roohi, Rakhshan; Webb, John A.

    2016-05-01

    Rainfed agrosystems are important components of the world's food production system and account for 65-95% of total agriculture. In contrast to irrigated production systems, relatively little attention has been paid to understanding the hydrological interactions between the components of rainfed agrosystems and their impact on water resources, especially groundwater. A new model, the Surface Energy Balance Algorithm for Rainfed Agriculture (SEBARA), has been developed to estimate the spatial pattern of evapotranspiration in these agrosystems using satellite images (thermal, infrared and visible spectra). The model was calibrated for two competing land uses (Eucalyptus globules tree plantations and pastures) in adjacent catchments in western Victoria, southeastern Australia. Using measurements from a flux tower in the pasture catchment and adjusted sapflow measurements in the plantation catchment, an estimation accuracy of 95% was achieved. The tree plantations had higher available net radiation, lower soil heat flux and higher latent heat flux, resulting in 15-20% higher evapotranspirative demand than the pasture, depending upon the age and canopy of plantations. The evapotranspiration rate of plantations declines where groundwater depth is >12m or where shallow groundwater is saline. The shallow root system of the pasture means that it relies solely on soil moisture to meet its water requirements and thus has lower evapotranspiration, which varies according to the pasture species.

  2. Long-term increase in diffuse groundwater recharge following expansion of rainfed cultivation in the Sahel, West Africa

    NASA Astrophysics Data System (ADS)

    Ibrahim, Maïmouna; Favreau, Guillaume; Scanlon, Bridget R.; Seidel, Jean Luc; Le Coz, Mathieu; Demarty, Jérôme; Cappelaere, Bernard

    2014-09-01

    Rapid population growth in sub-Saharan West Africa and related cropland expansion were shown in some places to have increased focused recharge through ponds, raising the water table. To estimate changes in diffuse recharge, the water content and matric potential were monitored during 2009 and 2010, and modeling was performed using the Hydrus-1D code for two field sites in southwest Niger: (1) fallow land and (2) rainfed millet cropland. Monitoring results of the upper 10 m showed increased water content and matric potential to greater depth under rainfed cropland (>2.5 m) than under fallow land (≤1.0 m). Model simulations indicate that conversion from fallow land to rainfed cropland (1) increases vadose-zone water storage and (2) should increase drainage flux (˜25 mm year-1) at 10-m depth after a 30-60 year lag. Therefore, observed regional increases in groundwater storage may increasingly result from diffuse recharge, which could compensate, at least in part, groundwater withdrawal due to observed expansion in irrigated surfaces; and hence, contribute to mitigate food crises in the Sahel.

  3. Use of Earth Observation for Geospatial Crop Water Accounting of Rain-Fed Agro-Ecosystem in India

    NASA Astrophysics Data System (ADS)

    Patel, N. R.; Manish, S.; Kumar, S.

    2011-08-01

    Use of earth observation by means of remote sensing and in-situ meteorological network in integrated manner have improved ability to track water availability and associated yield reduction in rain-fed crops as potential indicators of early warning and food security. the present study aims at monitoring of WRSI and production potential of rain-fed agro-ecosystems in eastern Rajasthan. The study was carried out during the kharif season using remote sensing, meteorology and soil information from year 1998 to 2004. Important datasets used in the study are Dekadal Normalized Difference Vegetation Index (NDVI) from SPOT-VEGETATION, gridded rainfall based on 300 rain-gauge stations, reference ET (ETo), and gridded soil water holding capacity (WHC). In addition, crop statistics and crop calendar information were also used in this study. The phenological metrices from time-series of SPOT-VGT NDVI were derived on inter-annual scales by applying Gaussian fit within TIMESAT procedure. WRSI was found promising in capturing inter-annual and spatial variability in water availability to rain-fed crops. The WRSI has also showed significant relationship with reported yield particularly in drone-prone areas. Water limited-yield stays on higher side but it has showed strong response to large scale drought.

  4. Extraction of light filth from rice flours, extruded rice products, and rice paper: collaborative study.

    PubMed

    Dent, R G

    1982-09-01

    Two new methods were developed for the extraction of rodent hairs and insect fragments from rice products: one for rice flour and one for extruded rice products and rice paper. A 100 g sample of rice flour was extracted with mineral oil-40% isopropanol, followed by a water phase as needed for additional cycles. For extruded rice products and rice paper, a 225 g sample of each was initially extracted as above, followed by a single extraction with mineral oil-20% isopropanol. Both methods used an acid hydrolysis pretreatment followed by wet sieving and a percolator extraction. Average rodent hair recoveries were 77.8% for rice flour and 82.2% for extruded rice products and rice paper. Average insect fragment recoveries were 89.6% for rice flour and 91.9% for extruded rice products and rice paper. Both methods were adopted official first action. PMID:7130079

  5. Cooked rice texture and rice flour pasting properties; impacted by rice temperature during milling.

    PubMed

    Saleh, Mohammed; Meullenet, Jean-Francois

    2015-03-01

    Rice milling plays a key factor in determining rice quality and value. Therefore accurate quality assessments are critical to the rice industry. This study was undertaken to assess the effect of exposing rice to elevated temperatures during milling, on cooked rice texture and rice flour pasting properties. Two long (Cybonnett and Francis) and one medium (Jupiter) rice (oryzae sativa L.) cultivars were milled using McGill laboratory mill for 30 and 40 s after warmed up the mill before milling. Four different milling temperatures per milling duration were achieved. Cooked rice texture properties were assessed using a uniaxial compression test and rice flour pasting properties measured using a TA-2000 rheometer. Results of this study showed that exposure of rice to high temperatures during milling significantly decreased cooked rice firmness. An increase in milled rice temperature after milling from 10.0 to 13.3 °C resulted in a 5.4 and 8.1 N decrease in cooked rice firmness. Although not always significant, the increase in milled rice temperature during milling resulted in an increase in cooked rice stickiness. The increase in milling temperature also showed significant increase in rice flour pasting properties. Changes in rice functional characteristics were attributed to the changes occurring to rice chemical constituents due to temperature exposure as indicated by the increase in rice protein hydrophobicity. Proteins are known to affect rice starch water holding capacity and other starch gelatinization properties. PMID:25745230

  6. Elucidation of rice rhizosphere metagenome in relation to methane and nitrogen metabolism under elevated carbon dioxide and temperature using whole genome metagenomic approach.

    PubMed

    Bhattacharyya, P; Roy, K S; Das, M; Ray, S; Balachandar, D; Karthikeyan, S; Nayak, A K; Mohapatra, T

    2016-01-15

    Carbon (C) and nitrogen (N) mineralization is one of the key processes of biogeochemical cycling in terrestrial ecosystem in general and rice ecology in particular. Rice rhizosphere is a rich niche of microbial diversity influenced by change in atmospheric temperature and concentration of carbon dioxide (CO2). Structural changes in microbial communities in rhizosphere influence the nutrient cycling. In the present study, the bacterial diversity and population dynamics were studied under ambient CO2 (a-CO2) and elevated CO2+temperature (e-CO2T) in lowland rice rhizosphere using whole genome metagenomic approach. The whole genome metagenomic sequence data of lowland rice exhibited the dominance of bacterial communities including Proteobacteria, Firmicutes, Acidobacteria, Actinobacteria and Planctomycetes. Interestingly, four genera related to methane production namely, Methanobacterium, Methanosphaera, Methanothermus and Methanothermococcus were absent in a-CO2 but noticed under e-CO2T. The acetoclastic pathway was found as the predominant pathway for methanogenesis, whereas, the serine pathway was found as the principal metabolic pathway for CH4 oxidation in lowland rice. The abundances of reads of enzymes in the acetoclastic methanogenesis pathway and serine pathways of methanotrophy were much higher in e-CO2T (328 and 182, respectively) as compared with a-CO2 (118 and 98, respectively). Rice rhizosphere showed higher structural diversities and functional activities in relation to N metabolism involving nitrogen fixation, assimilatory and dissimilatory nitrate reduction and denitrification under e-CO2T than that of a-CO2. Among the three pathways of N metabolism, dissimilarity pathways were predominant in lowland rice rhizosphere and more so under e-CO2T. Consequently, under e-CO2T, CH4 emission, microbial biomass nitrogen (MBN) and dehydrogenase activities were 45%, 20% and 35% higher than a-CO2, respectively. Holistically, a high bacterial diversity and

  7. Breeding disease-resistant wheats for tropical highlands and lowlands.

    PubMed

    Dubin, H J; Rajaram, S

    1996-01-01

    Wheat is grown on about 10 million ha in the tropical highlands and lowlands of the world, where it is an important food source. Many farmers in these areas work under subsistence conditions. Wheat diseases in tropical regions can be severe and require significant efforts to control. For economic and environmental reasons, host plant resistance is the most appropriate and sustainable disease control method. We describe highland and lowland tropical wheat regions and discuss CIMMYT's breeding strategies, philosophies, and progress in developing resistance to the major diseases such as rusts, foliar blights, fusarium scab, BYD, and spot blotch. Additionally, we review the role of national wheat research programs and beneficial spillovers of our combined breeding efforts to other wheat production areas of the world. PMID:15012554

  8. The consequences of pleistocene climate change on lowland neotropical vegetation

    SciTech Connect

    De Oliveira, P.E.; Colinvaux, P.A. )

    1994-06-01

    Palynological reconstructions indicate that lowland tropical America was subject to intense cooling during the last ice-age. The descent of presently montane taxa into the lowlands of Amazonia and Minas Gerais indicate temperature depressions ranging from 5[degrees]C to 9[degrees]C cooler-than-present. The strengthened incursion of southerly airmasses caused a reassortment of vegetation throughout Amazonia. Presently allopatric species are found to have been sympatric as novel forest assemblages and formed and dissolved. Modest drying, perhaps a 20% reduction in precipitation, accounts for all the records that show a Pleistocene expansion of savanna. No evidence is found to support the fragmentation of Amazonian forests during glacial times, and the hypothesis of forest refuges as an explanation of tropical speciation is rejected on empirical grounds.

  9. The groundwater exchange rate of the southern Baltic coastal lowland

    NASA Astrophysics Data System (ADS)

    Burzyński, K.; Sadurski, A.

    1990-11-01

    The groundwater of the southern Baltic lowlands usually occurs in particular hydrogeological conditions. The lowland is mostly covered by peats several metres in thickness. Peatbog water is isolated from deeper aquifers and has different chemical composition. Salty, relic groundwater of marine origin from the Atlantic period of the Holocene (Littorina transgression) may have survived in the deeper coastal aquifers in places of sluggish flow. The results of mathematical modelling of groundwater circulation show that the flow rate and local directions of groundwater change during the year, depending on the rate of groundwater recharge by precipitation. We present here an unsteady flow model, which makes it possible to predict the water table fluctuations during a year at any point of the area studied. The calculation of the groundwater exchange rate did not confirm the presence of any places of very sluggish groundwater flow, where salty, young relic water might have survived.

  10. Postconflict behavior in captive western lowland gorillas (Gorilla gorilla gorilla).

    PubMed

    Mallavarapu, S; Stoinski, T S; Bloomsmith, M A; Maple, T L

    2006-08-01

    Postconflict (PC) behaviors, including reconciliation and consolation, have been observed in many primate and several nonprimate species. Using the PC-matched control (MC) method, PC behavior was examined in two groups (n=13) of captive western lowland gorillas, a species for which no conflict resolution data have been published. Analyses of 223 conflicts showed significantly more affiliation between former opponents after a conflict when compared to control periods, indicating reconciliation. Results also showed significantly more affiliation between the victim and a third-party after a conflict, indicating consolation. Both solicited and unsolicited consolation were observed. The majority of the affiliative interactions observed for both reconciliation and consolation were social proximity, which suggests that unlike most nonhuman primates, proximity, rather than physical contact, may be the main mechanism for resolving conflicts in western lowland gorillas. PC behavior was not uniform throughout the groups, but rather varied according to dyad type. PMID:16847973

  11. Effect of tillage system on soil temperature in a rainfed Mediterranean Vertisol

    NASA Astrophysics Data System (ADS)

    Muñoz-Romero, Veronica; Lopez-Bellido, Luis; Lopez-Bellido, Rafael J.

    2015-10-01

    Soil temperature is a factor that influences the rates of physical, chemical, and biological reactions in soils and has a strong influence on plant growth. A field study was conducted during 2006-2007 and 2009-2010 on a typical rainfed Mediterranean Vertisol to determine the effects of the tillage system and the crop on soil temperature. The experimental treatments were the tillage system (no-tillage and conventional tillage) and the crop (wheat and faba bean). Soil temperature was measured at a 20 cm depth at 1 h intervals from December 1st to November 30th of 2006-2007 and 2009-2010. There was a highly significant relationship between air temperature (both maximum and minimum) and soil temperature for the two tillage systems. Soil temperature was similar in the growing season for both crops but was higher in the conventional tillage than in the no-tillage system, with differences between 0.7 and 2.6°C depending on the month of the year. A higher soil temperature with conventional tillage can be beneficial in the cold sowing period (November-December), improving crop establishment. In contrast, in critical periods with water deficits (spring) during which grain formation occurs, the lower temperature corresponding to the no-tillage system would be more favourable.

  12. Making the best of climatic variability: options for upgrading rainfed farming in water scarce regions.

    PubMed

    Rockström, J

    2004-01-01

    Coping with climatic variability for livelihood security is part of everyday life for rural communities in semi-arid and dry sub-humid savannas. Water scarcity caused by rainfall fluctuations is common, causing meteorological droughts and dry spells. However, this paper indicates, based on experiences in sub-Saharan Africa and India, that the social impact on rural societies of climatically induced droughts is exaggerated. Instead, water scarcity causing food deficits is more often caused by management induced droughts and dry spells. A conceptual framework to distinguish between manageable and unmanageable droughts is presented. It is suggested that climatic droughts require focus on social resilience building instead of land and water resource management. Focus is then set on the manageable part of climatic variability, namely the almost annual occurrence of dry spells, short 2-4 week periods of no rainfall, affecting farmer yields. On-farm experiences in savannas of sub-Saharan Africa of water harvesting systems for dry spell mitigation are presented. It is shown that bridging dry spells combined with soil fertility management can double and even triple on-farm yield levels. Combined with innovative systems to ensure maximum plant water availability and water uptake capacity, through adoption of soil fertility improvement and conservation tillage systems, there is a clear opportunity to upgrade rainfed farming systems in vulnerable savanna environments, through appropriate local management of climatic variability. PMID:15195432

  13. Breeding high-yielding drought-tolerant rice: genetic variations and conventional and molecular approaches

    PubMed Central

    Kumar, Arvind; Dixit, Shalabh; Ram, T.; Yadaw, R. B.; Mishra, K. K.; Mandal, N. P.

    2014-01-01

    The increased occurrence and severity of drought stress have led to a high yield decline in rice in recent years in drought-affected areas. Drought research at the International Rice Research Institute (IRRI) over the past decade has concentrated on direct selection for grain yield under drought. This approach has led to the successful development and release of 17 high-yielding drought-tolerant rice varieties in South Asia, Southeast Asia, and Africa. In addition to this, 14 quantitative trait loci (QTLs) showing a large effect against high-yielding drought-susceptible popular varieties were identified using grain yield as a selection criterion. Six of these (qDTY 1.1, qDTY 2.2, qDTY 3.1, qDTY 3.2, qDTY 6.1, and qDTY 12.1) showed an effect against two or more high-yielding genetic backgrounds in both the lowland and upland ecosystem, indicating their usefulness in increasing the grain yield of rice under drought. The yield of popular rice varieties IR64 and Vandana has been successfully improved through a well-planned marker-assisted backcross breeding approach, and QTL introgression in several other popular varieties is in progress. The identification of large-effect QTLs for grain yield under drought and the higher yield increase under drought obtained through the use of these QTLs (which has not been reported in other cereals) indicate that rice, because of its continuous cultivation in two diverse ecosystems (upland, drought tolerant, and lowland, drought susceptible), has benefited from the existence of larger genetic variability than in other cereals. This can be successfully exploited using marker-assisted breeding. PMID:25205576

  14. The amoeboid protists of cryogenic soils in the Kolyma Lowland

    NASA Astrophysics Data System (ADS)

    Shmakova, L. A.; Fedorov-Davydov, D. G.; Rivkina, E. M.

    2013-12-01

    The taxonomic diversity of amoeboid protists was examined in three types of tundra soils in the Kolyma Lowland, namely, a podzolized podbur, a cryozem, and a gleyzem. In total, 27 naked amoeba genera were identified in the analyzed samples. It was shown that the individual soil types house different communities of naked amoebas. The distribution of naked amoebas in the cryozem had two peaks: one in the upper organic horizon and the other at the boundary with the permafrost.

  15. Biological and physical conditions of macroinvertebrates in reference lowland streams

    NASA Astrophysics Data System (ADS)

    de Brouwer, Jan; Eekhout, Joris; Verdonschot, Piet

    2016-04-01

    Channelisation measures taken halfway the 20th century have had destructive consequences for the diversity of the ecology in the majority of the lowland streams in countries such as the Netherlands. Currently, stream restoration measures are being implemented in these degraded lowland streams, where design principles are often based on outdated relationships between biological and physical conditions. Little is known about the reference conditions in these streams. Therefore, the aim of this research is to quantify the relationships between biological and physical conditions of macroinvertebrates in reference lowland streams. The research was conducted in four near-natural lowland streams in Central Poland. Field data were obtained during a field campaign in 2011. The following data were obtained in a 50-m reach in each of the four streams: macroinvertebrate sampling, spatial habitat patterns, bathymetry, and flow-velocity. Furthermore, water level, light sensitivity and temperature sensors were installed to obtain the temporal dynamic of these streams. Macroinvertebrates were sampled in 9 different habitat types, i.e. sand, gravel, fine organic matter, stones, branches, leaves, silt, vegetation, and wood. Macroinvertebrates were determined to the highest taxonomic level possible. Data from the bathymetrical surveys were interpolated on a grid and bathymetrical metrics were determined. Flow velocity measurements were related to habitats and flow velocity metrics were determined. Analysis of the data shows that flow conditions vary among the different habitat, with a gradient from hard substrates towards soft substrates. Furthermore, the data show that stream as a unit best explains species composition, but also specific habitat conditions, such as substrate type and flow velocity, correlate with species composition. More specific, the data shows a strong effect of wood on species composition. These findings may have implications for stream restoration design, which

  16. Morphological Assessment of Reconstructed Lowland Streams in the Netherlands

    NASA Astrophysics Data System (ADS)

    Hoitink, T.; Eekhout, J.; de Brouwer, J.; Verdonschot, P.

    2014-12-01

    Channelisation measures taken halfway the 20th century have had destructive consequences for the diversity of the ecology in the majority of the lowland streams in countries such as the Netherlands. Re-meandering is the common practice in restoring these lowland streams. Three lowland streams were monitored during the initial two years after construction of a new channel. The monitoring program included morphological surveys, sediment sampling, habitat pattern surveys, and discharge and water level measurements. Adjustments of the longitudinal bed profile formed the main morphological response. These adjustments were most likely caused by a lack of longitudinal connectivity of the streams as a whole, interrupting transport of sediment at locations of weirs and culverts. Bank erosion was observed only in a limited number of channel bends, and was often related to floodplain heterogeneity. Longitudinal channel bed adjustments and bank erosion were mainly caused by exogenous influences. In channel bends, the cross-sectional shape transformed from trapezoidal to the typical asymmetrical shape as found in meandering rivers. This behaviour can be attributed to an autogenous response to the prevailing flow conditions. Due to the prevailing fine sediment characteristics, bed material is readily set in motion and is being transported during the entire year. The existing design principles fail to address the initial morphological development after reconstruction. An evaluation of pre-set targets to realize water depth and flow velocity ranges shows the current procedures to be deficient. Based on this unfavourable evaluation, and the two-dimensional nature of habitat patterns needed to improve the conditions for stream organisms, we recommend to predict morphological developments as part of the design procedures for lowland stream restoration in the Netherlands.

  17. How Will Climate Change Impact Water Consumption for Rice Irrigation in Southern Brazil?

    NASA Astrophysics Data System (ADS)

    dos Santos, T. V.; Twine, T. E.

    2015-12-01

    Globally, agricultural water use accounts for most of the water that is withdrawn from surface water and groundwater. Rice, one of the world's leading food crops, requires that fields be continuously flooded to obtain optimal yields. High air temperature and consecutive rainless days in rice-growing areas can significantly reduce rice yields, leading to food scarcity. Climate change is expected to affect water demand for rice via changes in rainfall regime, soil water balance, and evapotranspiration. Higher temperatures and increased variability of precipitation are predicted to increase water demand and could potentially require more irrigation in lowland rice-growing areas. In this study we present the first results from model simulations in which we integrated a rice model into the Agro-IBIS dynamic ecosystem model. We predict the impact of climate change on the water use requirement of rice production in southern Brazil and evaluate changes in irrigation needed to meet minimum water demand to sustain current yields. Brazil is the 9th top rice producer in the world, and southern Brazil accounts for about 80% of the national production. The Agro-IBIS model was driven with historic weather data provided by CRU (1961-90) and with two future climate scenarios from the Coupled Model Intercomparison Project Phase 5 (CMIP5) for 2015-2100 - Representative Concentration Pathways 4.5 (RCP45) and 8.5 (RCP85). On an hourly time step, Agro-IBIS accounts for gains (precipitation) and losses (evaporation, transpiration, infiltration and runoff) of water in each grid cell, and uses rules to irrigate in order to maintain a specific height of standing water on the field. Simulated historic and future amounts of irrigated water needed to maintain this water height will be evaluated to predict future water demand for rice production in southern Brazil.

  18. Characterizing groundwater contribution to lowland streams using Travel Time Distribution

    NASA Astrophysics Data System (ADS)

    Petrus Kaandorp, Vincentius; Gerardus Bernardus de Louw, Petrus; Kuijper, Martina Johanna Maria; Broers, Hans Peter

    2015-04-01

    In recent years, it has become apparent that European freshwaters will fail to meet the ecological guidelines set for 2015 by the Water Framework Directive. 55 % of European surface water bodies have been reported to have a less than good ecological status, while the goal for 2015 is to have a good status for all water bodies. The deterioration of freshwater aquatic ecosystems is a problem worldwide. The current study, part of the EU FP7 project Managing Aquatic ecosystems and water Resources under multiple Stress (MARS), addresses this issue by focusing on the effect of multiple stressors. Freshwater ecosystems are directly linked to the characteristics of catchments and streams they are located in as this determines the habitats present. One of these characteristics, the groundwater contribution to streams, is important for aquatic ecosystems as it influences (1) river discharge, (2) water quality and (3) temperature and (4) the riparian zone. Groundwater provides streams with sufficient base flow, good quality water and a stable temperature. Compared to hilly slope catchments, the lowland catchments of The Netherlands lack much topography and surface runoff, and as such, virtually all stream water originates from groundwater. Current approaches do not sufficiently address the contribution of groundwater to stream flow in lowland catchments, as existing hydrograph separation methods provide little informative value about the groundwater contribution itself. The amount and quality of groundwater input to streams depends on its flow path and travel time. Especially in lowland catchments the groundwater input in streams is composed of a wide range of travel times which vary in time and space and have different quantitative and qualitative characteristics. Thus in order to successfully manage lowland streams, it is critical to specify the input of groundwater in more detail and take in account the temporal and spatial variability in travel times. We will present an

  19. Energy from rice residues

    SciTech Connect

    Mahin, D.B.

    1990-03-01

    Developing countries produce millions of tons of rice husks and straw as a byproduct of harvesting rice. Although some of these rice residues are used for fuel or other purposes, most are burned for disposal or just dumped. However, since the mid- 1980's, industrial plants for rice residue utilization have been installed in several countries and are planned in a number of others. The report provides information on systems to produce energy from rice residues that are commercially available in the United States, Europe, and various developing countries, with an emphasis on those currently used or sold on an international level. Specifically reviewed are the use of rice husks to produce: (1) industrial process heat either directly from furnaces or by generating low pressure steam in boilers; (2) mechanical and electrical power for rice milling via steam engine systems, steam turbine/generator systems, and gasifier/engine systems; and (3) electric power for the grid. The outlook for producing energy from rice straw is also assessed. In addition, the prospects for the use of energy from husks or straw in the processing of rice bran are reviewed.

  20. Towards Global Simulation of Irrigation in a Land Surface Model: Multiple Cropping and Rice Paddy in Southeast Asia

    NASA Technical Reports Server (NTRS)

    Beaudoing, Hiroko Kato; Rodell, Matthew; Ozdogan, Mutlu

    2010-01-01

    Agricultural land use significantly influences the surface water and energy balances. Effects of irrigation on land surface states and fluxes include repartitioning of latent and sensible heat fluxes, an increase in net radiation, and an increase in soil moisture and runoff. We are working on representing irrigation practices in continental- to global-scale land surface simulation in NASA's Global Land Data Assimilation System (GLDAS). Because agricultural practices across the nations are diverse, and complex, we are attempting to capture the first-order reality of the regional practices before achieving a global implementation. This study focuses on two issues in Southeast Asia: multiple cropping and rice paddy irrigation systems. We first characterize agricultural practices in the region (i.e., crop types, growing seasons, and irrigation) using the Global data set of monthly irrigated and rainfed crop areas around the year 2000 (MIRCA2000) dataset. Rice paddy extent is identified using remote sensing products. Whether irrigated or rainfed, flooded fields need to be represented and treated explicitly. By incorporating these properties and processes into a physically based land surface model, we are able to quantify the impacts on the simulated states and fluxes.

  1. Monitoring of rice cropping intensity in the upper Mekong Delta, Vietnam using time-series MODIS data

    NASA Astrophysics Data System (ADS)

    Chen, C. F.; Son, N. T.; Chang, L. Y.

    2012-01-01

    Information on rice growing areas is important for policymakers to devise agricultural plans. This research explores the monitoring of rice cropping intensity in the upper Mekong Delta, Vietnam (from 2001 to 2007) using time-series MODIS NDVI 250-m data. Data processing includes three steps: (1) noise is filtered from the time-series NDVI data using empirical mode decomposition (EMD); (2) endmembers are extracted from the filtered time-series data and trained in a linear mixture model (LMM) for classification of rice cropping systems; and (3) classification results are verified by comparing them with the ground-truth and statistical data. The results indicate that EMD is a good filter for noise removal from the time-series data. The classification results confirm the validity of LMM, giving an overall accuracy of 90.1% and a Kappa coefficient of 0.7. The lowest producer and user accuracies were associated with single crop rain-fed rice class due to the mixed pixel problems. A strong yearly correlation at the district level was revealed in the MODIS-derived areas (R2 ⩾ 0.9). Investigation of interannual changes in rice cropping intensity from 2001 to 2007 showed a remarkable conversion from double to triple crop irrigated rice from 2001 to 2003, especially in the Thoai Son and Phu Tan districts. A big conversion from triple crop rice back to double crop rice cultivation was also observed in Phu Tan from 2005 to 2006. These changes were verified by visual interpretation of Landsat images and examination of NDVI profiles.

  2. Characterising groundwater-dominated lowland catchments: the UK Lowland Catchment Research Programme (LOCAR)

    NASA Astrophysics Data System (ADS)

    Wheater, H. S.; Peach, D.; Binley, A.

    2007-01-01

    This paper reports on a major UK initiative to address deficiencies in understanding the hydro-ecological response of groundwater-dominated lowland catchments. The scope and objectives of this national programme are introduced and focus on one of three sets of research basins - the Pang/Lambourn Chalk catchments, tributaries of the river Thames in southern England. The motivation for the research is the need to support integrated management of river systems that have high ecological value and are subject to pressures that include groundwater abstraction for water supply, diffuse pollution, and land use and climate change. An overview of the research programme is provided together with highlights of some current research findings concerning the hydrological functioning of these catchments. Despite the importance of the Chalk as a major UK aquifer, knowledge of the subsurface movement of water and solutes is poor. Solute transport in the dual porosity unsaturated zone depends on fracture/matrix interactions that are difficult to observe; current experimental and modelling research supports the predominance of matrix flow and suggests that slow migration of a time-history of decades of nutrient loading is occurring. Groundwater flows are complex; catchments vary seasonally and are ill-defined and karst features are locally important. Groundwater flow pathways are being investigated using natural and artificial geochemical tracers based on experimental borehole arrays; stream-aquifer interaction research is using a combination of geophysics, borehole array geochemistry and longitudinal profiles of stream flow and solutes. A complex picture of localised subsurface inflows, linked to geological controls and karst features, and significant longitudinal groundwater flow below the river channel is emerging. Management implications are discussed. Strategies to control surface application of nutrients are expected to have little effect on groundwater quality for several

  3. Determinants for grading Malaysian rice

    NASA Astrophysics Data System (ADS)

    ChePa, Noraziah; Yusoff, Nooraini; Ahmad, Norhayati

    2016-08-01

    Due to un-uniformity of rice grading practices in Malaysia, zones which actively producing rice in Malaysia are using their own way of grading rice. Rice grading is important in determining rice quality and its subsequent price in the market. It is an important process applied in the rice production industry with the purpose of ensuring that the rice produced for the market meets the quality requirements of consumer. Two important aspects that need to be considered in determining rice grades are grading technique and determinants to be used for grading (usually referred as rice attributes). This article proposes the list of determinants to be used in grading Malaysian rice. Determinants were explored through combination of extensive literature review and series of interview with the domain experts and practitioners. The proposed determinants are believed to be beneficial to BERNAS in improving the current Malaysian rice grading process.

  4. Mitigation options for methane emissions from rice fields in the Philippines

    SciTech Connect

    Lantin, R.S.; Buendia, L.V.; Wassmann, R.

    1996-12-31

    The contribution of Philippine rice production to global methane emission and breakthroughs in methane emission studies conducted in the country are presented in this paper. A significant impact in the reduction of GHG emissions from agriculture can be achieved if methane emissions from ricefields can be abated. This study presents the contribution of Philippine rice cultivation to global methane emission and breakthroughs in methane emission studies in the country which address the issue of mitigation. Using the derived emission factors from local measurements, rice cultivation contributes 566.6 Gg of methane emission in the Philippines. This value is 62% of the total methane emitted from the agriculture sector. The emission factors employed which are 78% of the IPCC value for irrigated rice and 95% for rainfed rice were derived from measurements with an automatic system taken during the growth duration in the respective ecosystems. Plots drained for 2 weeks at midtillering and before harvest gave a significant reduction in methane emission as opposed to continuously flooded plots and plots drained before harvest. The cultivar Magat reduced methane emission by 50% as compared to the check variety IR72. The application of ammonium sulfate instead of urea reduced methane emission by 10% to 34%. Addition of 6 t ha{sup {minus}1} phosphogypsum in combination with urea reduced emission by 74% as opposed to plots applied with urea alone. It is also from the results of such measurements that abatement strategies are based as regards to modifying treatments such as water management, fertilization, and choice of rice variety. It is not easy to identify and recommend mitigation strategies that will fit a particular cropping system. However, the identified mitigation options provide focus for the abatement of methane emission from ricefields.

  5. Modelling field scale water partitioning using on-site observations in sub-Saharan rainfed agriculture

    NASA Astrophysics Data System (ADS)

    Makurira, H.; Savenije, H. H. G.; Uhlenbrook, S.

    2009-08-01

    Smallholder rainfed farming systems generally realise sub-optimal crop yields which are largely attributed to dry spell occurrences during crop growth stages. However, with improved farming practices, it seems possible to significantly increase yield levels even with little and highly variable rainfall. The presented results follow research conducted in the Makanya catchment in northern Tanzania where gross rainfall amounts to less than 400 mm/season which is insufficient to support staple food crops (e.g. maize). Alternative cultivation techniques such as runoff harvesting and in-field micro-storage structures are compared. These techniques aim to reduce soil and nutrient loss from the field but, more importantly, promote in-field infiltration and water retention. Water balance components have been observed in order to study water partitioning processes under different cultivation techniques. Based on rainfall, soil evaporation, transpiration, runoff and soil moisture measurements, a water balance model has been developed to simulate soil moisture variations over the growing season. It appears that about 50% of the diverted water leaves the root zone through deep percolation. Modelling shows that during the field trials the average productive transpiration flow ranged between 1.1-1.4 mm d-1 in the trial plots compared to 0.7-1.0 mm d-1 under traditional tillage practice. Productive transpiration processes accounted for 23-29% while losses to deep percolation accounted for 33-48% of the available water. Conclusions from the research are that the innovations tested are effective in enhancing soil moisture retention at field scale and that diversions allow crop growth moisture conditions to be attained with early rains. It is also concluded that there is more scope for efficient utilisation of the diverted runoff water if storage structures could be installed to regulate water flow to the root zone when required.

  6. Ammonia emissions from different fertilizing strategies in Mediterranean rainfed winter cereals

    NASA Astrophysics Data System (ADS)

    Bosch-Serra, Àngela D.; Yagüe, María R.; Teira-Esmatges, María R.

    2014-02-01

    Anthropogenic ammonia (NH3) emissions mainly result from agricultural activities where manure spreading plays a significant role. For a Mediterranean rainfed winter cereal system there is a lack of data regarding NH3 emissions. The aim of this work is to provide field data on N losses due to NH3 volatilization as a consequence of the introduction of slurries in fertilization strategies and also, to assess the influence of environmental conditions and slurry characteristics on emissions. The fertilizing strategies include the use of slurry from fattening pigs (PS), sows (PSS) and/or mineral fertilizer (M) as ammonium nitrate. Fertilizers were spread over the calcareous soil at sowing and/or at tillering at rates from 15 to 45 kg NH4+-N ha-1 for M and from 48.8 to 250.3 kg NH4+-N ha-1 for slurries. The NH3 emissions were quantified during three cropping seasons. Average losses from the total ammonium nitrogen applied ranged from 7 to 78% for M and from 6 to 64% for slurries and they were not directly proportional to the amounts of applied ammonium. The best results on NH3 volatilization reduction were registered when soil water content (SWC, 0-30 cm) was below 56% of its field capacity and also, when slurry dry matter (DM) was in the interval of 6.1-9.3% for PS or much lower (0.8%) for PSS. High slurry DM favoured crust formation and the lower rates promoted infiltration, both of which reduced NH3 emissions. Nevertheless, at tillering, the lower DM content was the most effective in controlling emissions (<9 kg NH3-N ha-1) and equalled M fertilizer in cumulative NH3 loss (p > 0.05). A single slurry application at tillering did not negatively affect yield biomass. The combining of recommended timing of applications with slurry DM content and SWC should allow producers to minimize volatilization while maintaining financial benefits.

  7. Conservation Agriculture Practices in Rainfed Uplands of India Improve Maize-Based System Productivity and Profitability.

    PubMed

    Pradhan, Aliza; Idol, Travis; Roul, Pravat K

    2016-01-01

    Traditional agriculture in rainfed uplands of India has been experiencing low agricultural productivity as the lands suffer from poor soil fertility, susceptibility to water erosion and other external pressures of development and climate change. A shift toward more sustainable cropping systems such as conservation agriculture production systems (CAPSs) may help in maintaining soil quality as well as improving crop production and farmer's net economic benefit. This research assessed the effects over 3 years (2011-2014) of reduced tillage, intercropping, and cover cropping practices customized for maize-based production systems in upland areas of Odisha, India. The study focused on crop yield, system productivity and profitability through maize equivalent yield and dominance analysis. Results showed that maize grain yield did not differ significantly over time or among CAPS treatments while cowpea yield was considered as an additional yield in intercropping systems. Mustard and horsegram grown in plots after maize cowpea intercropping recorded higher grain yields of 25 and 37%, respectively, as compared to those without intercropping. Overall, the full CAPS implementation, i.e., minimum tillage, maize-cowpea intercropping and mustard residue retention had significantly higher system productivity and net benefits than traditional farmer practices, i.e., conventional tillage, sole maize cropping, and no mustard residue retention. The dominance analysis demonstrated increasing benefits of combining conservation practices that exceeded thresholds for farmer adoption. Given the use of familiar crops and technologies and the magnitude of yield and income improvements, these types of CAPS should be acceptable and attractive for smallholder farmers in the area. This in turn should support a move toward sustainable intensification of crop production to meet future household income and nutritional needs. PMID:27471508

  8. Conservation Agriculture Practices in Rainfed Uplands of India Improve Maize-Based System Productivity and Profitability

    PubMed Central

    Pradhan, Aliza; Idol, Travis; Roul, Pravat K.

    2016-01-01

    Traditional agriculture in rainfed uplands of India has been experiencing low agricultural productivity as the lands suffer from poor soil fertility, susceptibility to water erosion and other external pressures of development and climate change. A shift toward more sustainable cropping systems such as conservation agriculture production systems (CAPSs) may help in maintaining soil quality as well as improving crop production and farmer’s net economic benefit. This research assessed the effects over 3 years (2011–2014) of reduced tillage, intercropping, and cover cropping practices customized for maize-based production systems in upland areas of Odisha, India. The study focused on crop yield, system productivity and profitability through maize equivalent yield and dominance analysis. Results showed that maize grain yield did not differ significantly over time or among CAPS treatments while cowpea yield was considered as an additional yield in intercropping systems. Mustard and horsegram grown in plots after maize cowpea intercropping recorded higher grain yields of 25 and 37%, respectively, as compared to those without intercropping. Overall, the full CAPS implementation, i.e., minimum tillage, maize–cowpea intercropping and mustard residue retention had significantly higher system productivity and net benefits than traditional farmer practices, i.e., conventional tillage, sole maize cropping, and no mustard residue retention. The dominance analysis demonstrated increasing benefits of combining conservation practices that exceeded thresholds for farmer adoption. Given the use of familiar crops and technologies and the magnitude of yield and income improvements, these types of CAPS should be acceptable and attractive for smallholder farmers in the area. This in turn should support a move toward sustainable intensification of crop production to meet future household income and nutritional needs. PMID:27471508

  9. Modelling Climate change influence on runoff and soil losses in a rainfed catchment with Mediterranean climate

    NASA Astrophysics Data System (ADS)

    Concepción Ramos, Maria; Martínez-Casasnovas, José A.

    2015-04-01

    The magnitude of erosion processes, widespread throughout the Mediterranean areas, may be enhanced due to changes in seasonal precipitation regimes and an increase of extreme events. The present research shows the results of possible effects of climate change on runoff and soil loss in a rainfed catchment located in the Barcelona province (NE Spain).In the study area, vines are the main land use, cultivated under the Penedès designation of origin. The present research shows the results of runoff and soil loss simulated using SWAT for a small basin with vines as main land use. Input data included detailed soil and land use maps, and daily climate data of the period 1998-2012. The analysis compared simulated results for years with different climatic conditions during that period and the average with predictions for the scenario 2020, 2050 and 2080 based on the HadCM3 GCM under A2 scenario and the trends observed in the area related to maximum rainfall intensity. The model was calibrated and validated using data recorded at different subbasins, using soil water and runoff samples. Taking into account the predicted changes in temperature and precipitation, the model simulated a decrease in soil loss associated with a decrease in runoff, mainly driven by an increase in evapotranspiration. However, the trend in soil losses varied when the changes in precipitation could balance the increase of evapotranspiration and also due to the increase of rainfall intensity. An increase in maximum rainfall intensity in spring and autumn (main rainy seasons) produced significant increases in soil loss: by up to 12% for the 2020 scenario and up to 57% for the 2050 scenario, although high differences may exists depending on rainfall characteristics. The research confirmed the difficulty of predicting future soil loss in this region, which has a very high climate inter-annual variability.

  10. [Effects of Tillage on Soil Respiration and Root Respiration Under Rain-Fed Summer Corn Field].

    PubMed

    Lu, Xing-li; Liao, Yun-cheng

    2015-06-01

    To explore the effects of different tillage systems on soil respiration and root respiration under rain-fed condition. Based on a short-term experiment, this paper investigated soil respiration in summer corn growth season under four tillage treatments including subsoiling tillage (ST), no tillage (NT), rotary tillage (RT) and moldboard plow tillage (CT). The contribution of root respiration using root exclusion method was also discussed. The results showed that soil respiration rate presented a single peak trend under four tillage methods during the summer corn growing season, and the maximum value was recorded at the heading stage. The trends of soil respiration were as follows: heading stage > flowering stage > grain filling stage > maturity stage > jointing stage > seedling stage. The trends of soil respiration under different tillage systems were as follows: CT > ST > RT > NT. There was a significant correlation between soil respiration rate and soil temperatures (P < 0.05), which could explain 35%-75% variability of soil respiration using exponential function equation. However, there was no significant correlation between soil respiration rate and soil moisture. Root respiration accounted for 45.13%-56.86% of the proportion of soil respiratio n with the mean value 51.72% during the summer corn growing season under different tillage systems. Therefore, root exclusion method could be used to study the contribution of crop growth to carbon emission, to compare effects of different tillage systems on the contribution of root respiration provides the bases for selecting the measures to slow down the decomposition of soil carbon. PMID:26387335

  11. Assessment of agricultural drought in rainfed cereal production areas of northern China

    NASA Astrophysics Data System (ADS)

    Li, Rui; Tsunekawa, Atsushi; Tsubo, Mitsuru

    2015-10-01

    Agricultural drought assessment is an important tool for water management in water-scarce regions such as Inner Mongolia and northeastern China. Conventional methods have difficulty of clarifying long-term influences of drought on regional agricultural production. To accurately evaluate regional agricultural drought, we assessed the performance of drought indices by constructing a new assessment framework with three components: crop model calibration and validation, drought index calculation, and index assessment (standard period setting, mean value and agreement assessments). The Environmental Policy Integrated Climate (EPIC) model simulated well of county-level wheat and maize yields in the nine investigated counties. We calculated a major crop-specific index yield reduction caused by water stress (WSYR) in the EPIC crop model, by relating potential and rainfed yields. Using 26 agricultural drought cases, we compared WSYR with two meteorological drought indices: precipitation (P) and aridity index (AI). The results showed that WSYR had greater agreement (85 %) than either the precipitation (65 %) or aridity index (68 %). The temporal trend of the indices over the period 1962-2010 was tested using three approaches. The result via WSYR revealed a significant increase in the trend of agricultural drought in drought-prone counties, which could not be shown by the precipitation and aridity indices. Total number of dry year via WSYR from 1990s to 2000s increases more sharply than via P or AI. As shown by WSYR, the number of dry years in northeastern China and Inner Mongolia is generally increasing, particularly after the 2000s, in the western part of the study area. The study reveals the usefulness of the framework for drought index assessment and indicates the potential of WSYR and possible drought cases for drought classification.

  12. Genome-wide association for grain yield under rainfed conditions in historical wheat cultivars from Pakistan

    PubMed Central

    Ain, Qurat-ul; Rasheed, Awais; Anwar, Alia; Mahmood, Tariq; Imtiaz, Muhammad; Mahmood, Tariq; Xia, Xianchun; He, Zhonghu; Quraishi, Umar M.

    2015-01-01

    Genome-wide association studies (GWAS) were undertaken to identify SNP markers associated with yield and yield-related traits in 123 Pakistani historical wheat cultivars evaluated during 2011–2014 seasons under rainfed field conditions. The population was genotyped by using high-density Illumina iSelect 90K single nucleotide polymorphism (SNP) assay, and finally 14,960 high quality SNPs were used in GWAS. Population structure examined using 1000 unlinked markers identified seven subpopulations (K = 7) that were representative of different breeding programs in Pakistan, in addition to local landraces. Forty four stable marker-trait associations (MTAs) with -log p > 4 were identified for nine yield-related traits. Nine multi-trait MTAs were found on chromosomes 1AL, 1BS, 2AL, 2BS, 2BL, 4BL, 5BL, 6AL, and 6BL, and those on 5BL and 6AL were stable across two seasons. Gene annotation and syntey identified that 14 trait-associated SNPs were linked to genes having significant importance in plant development. Favorable alleles for days to heading (DH), plant height (PH), thousand grain weight (TGW), and grain yield (GY) showed minor additive effects and their frequencies were slightly higher in cultivars released after 2000. However, no selection pressure on any favorable allele was identified. These genomic regions identified have historically contributed to achieve yield gains from 2.63 million tons in 1947 to 25.7 million tons in 2015. Future breeding strategies can be devised to initiate marker assisted breeding to accumulate these favorable alleles of SNPs associated with yield-related traits to increase grain yield. Additionally, in silico identification of 454-contigs corresponding to MTAs will facilitate fine mapping and subsequent cloning of candidate genes and functional marker development. PMID:26442056

  13. Spotlight on rice: an update from the Rice Division

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This short paper is a 'spotlight' on the Rice Division of the Marican Association of Cereal Chemists, International and features an update and future challenges in rice research and industry. Since rice is consumed largely as milled white rice intact kernals, size, shape, color, appearance, function...

  14. Rice (Oryza) hemoglobins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice (Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a sin...

  15. Registration of 'Cybonnet' Rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Cybonnet’ rice is a high-yielding, short-season, long-grain cultivar. It originated form the cross ‘Cypress’//’Newbonnet’/’Katy’ made at the University of Arkansas Rice Research and Extension Center in Stuttgart, AR. Cybonnet is similar in maturity to ‘Kaybonnet’ and ‘Wells’, is a simidwarf culti...

  16. Making rice even healthier!

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice is a naturally healthy food, but what if it could be made even healthier? Would Americans eat more rice if it could be advertised to be a 'New and Improved' source of calcium to promote bone growth, or iron to prevent anemia? Grocery stores are full of foods that are vitamin enhanced to attract...

  17. Registration of 'Medark' Rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Medark’ rice is a high-yielding, early maturing, semidwarf, medium-grain cultivar. It originated from the cross ‘Bengal’/’Short Rico’ and is similar in maturity to Bengal. It has improved disease resistance to rice blase, brown spot and straighthead. Medark has a lodging resistance slightly less...

  18. An evaluation of the water utilization and grain production of irrigated and rain-fed croplands in China.

    PubMed

    Cao, Xinchun; Wang, Yubao; Wu, Pute; Zhao, Xining; Wang, Juan

    2015-10-01

    Irrigation plays a major role in Chinese agricultural production, as China is experiencing water and food scarcity. Assessing water use (WU) and water productivity (WP) will contribute to regional water management and grain production improvement. This paper quantifies the water use and productivity in grain production for 31 Chinese provinces, autonomous regions and municipalities (PAMs) by distinguishing between irrigated and rain-fed farmland. An indicator of marginal productivity of blue water (MWPb) is established and calculated to evaluate irrigation profits. National water use (WUt) for grain cultivation from 1998 to 2010 was approximately 689.04 Gm(3) (42.26% blue water and 57.74% green water). The productive water proportions for irrigated and total croplands were 65.57% and 76.85%, respectively. Water use compositions from both blue-green and productive-unproductive perspectives changed slightly over time. The water use productivity (WPU) and water consumption productivity (WPC) for integrated grain products of China during the study period were 0.747 and 0.972 kg/m(3), respectively. The spatial distribution patterns of irrigated WPs (WPUI, WPCI) were consistent with those for total cropland. China has achieved sufficient food supply without increasing water use. The national MWPb was estimated to be 0.673 kg/m(3), revealing a higher increase in crop yield on irrigated land compared to rain-fed land. The northeast provinces urgently need to improve irrigation efficiency, and the North China Plain PAMs should promote rain-fed crop yield to increase grain production and control water use in the future. PMID:26005745

  19. Biochar helps enhance maize productivity and reduce greenhouse gas emissions under balanced fertilization in a rainfed low fertility inceptisol.

    PubMed

    Zhang, Dengxiao; Pan, Genxing; Wu, Gang; Kibue, Grace Wanjiru; Li, Lianqing; Zhang, Xuhui; Zheng, Jinwei; Zheng, Jufeng; Cheng, Kun; Joseph, Stephen; Liu, Xiaoyu

    2016-01-01

    Maize production plays an important role in global food security, especially in arid and poor-soil regions. Its production is also increasing in China in terms of both planting area and yield. However, maize productivity in rainfed croplands is constrained by low soil fertility and moisture insufficiency. To increase the maize yield, local farmers use NPK fertilizer. However, the fertilization regime (CF) they practice is unbalanced with too much nitrogen in proportion to both phosphorus and potassium, which has led to low fertilizer use efficiency and excessive greenhouse gases emissions. A two-year field experiment was conducted to assess whether a high yielding but low greenhouse gases emission system could be developed by the combination of balanced fertilization (BF) and biochar amendment in a rainfed farmland located in the Northern region of China. Biochar was applied at rates of 0, 20, and 40 t/ha. Results show that BF and biochar increased maize yield and partial nutrient productivity and decreased nitrous oxide (N2O) emission. Under BF the maize yield was 23.7% greater than under CF. N2O emissions under BF were less than half that under CF due to a reduced N fertilizer application rate. Biochar amendment decreased N2O by more than 31% under CF, while it had no effect on N2O emissions under BF. Thus BF was effective at maintaining a high maize yield and reducing greenhouse gases emissions. If combined with biochar amendment, BF would be a good way of sustaining low carbon agriculture in rainfed areas. PMID:25959223

  20. Multiscale object-based drought monitoring and comparison in rainfed and irrigated agriculture from Landsat 8 OLI imagery

    NASA Astrophysics Data System (ADS)

    Ozelkan, Emre; Chen, Gang; Ustundag, Burak Berk

    2016-02-01

    Drought is a rapidly rising environmental issue that can cause hardly repaired or unrepaired damages to the nature and socio-economy. This is especially true for a region that features arid/semi-arid climate, including the Turkey's most important agricultural district - Southeast Anatolia. In this area, we examined the uncertainties of applying Landsat 8 Operational Land Imager (OLI) NDVI data to estimate meteorological drought - Standardized Precipitation Index (SPI) - measured from 31 in-situ agro-meteorological monitoring stations during spring and summer of 2013 and 2014. Our analysis was designed to address two important, yet under-examined questions: (i) how does the co-existence of rainfed and irrigated agriculture affect remote sensing drought monitoring in an arid/semi-arid region? (ii) What is the role of spatial scale in drought monitoring using a GEOBIA (geographic object-based image analysis) framework? Results show that spatial scale exerted a higher impact on drought monitoring especially in the drier year 2013, during which small scales were found to outperform large scales in general. In addition, consideration of irrigated and rainfed areas separately ensured a better performance in drought analysis. Compared to the positive correlations between SPI and NDVI over the rainfed areas, negative correlations were determined over the irrigated agricultural areas. Finally, the time lag effect was evident in the study, i.e., strong correlations between spring SPI and summer NDVI in both 2013 and 2014. This reflects the fact that spring watering is crucial for the growth and yield of the major crops (i.e., winter wheat, barley and lentil) cultivated in the region.

  1. Holocene pedogenic change and the emergence and decline of rain-fed cereal agriculture on the Chinese Loess Plateau

    NASA Astrophysics Data System (ADS)

    Huang, Chun Chang; Pang, Jiangli; Zhou, Qunying; Chen, Shu'e.

    2004-12-01

    Multi-disciplinary investigations were carried out in a Holocene eolian loess-soil profile in the centre of the Chinese Loess Plateau at the transition between the arid Mongolian steppe and the semi-arid mixed forest, and also the transitional zone between nomadism and the rain-fed cereal agriculture in history. The cultural remains of an earliest rain-fed cereal agriculture, and also the remains of a Bronze Age nomadic community identified in the profile indicate that the regional emergence and decline of the rain-fed cereal agriculture was closely connected with the change in dust accumulation and soil formation. The climatic proxies derived from the profile show that monsoonal climatic variation, especially precipitation behind the pedogenic change, was ultimately responsible for the cultural and land-use change over the Loess Plateau. Increased precipitation brought on by southeast monsoon, conditioned the domestication and cultivation of millets in the southern part of the region during 8000-7000 a BP at the beginning of the Holocene climatic optimum. Sufficient precipitation and the well-developed fertile soils facilitated the expansion of millets cultivation to the northern Loess Plateau and the southern Mongolian Plateau between 7000 a BP and 3600 a BP. Reduced precipitation and deteriorated land-use conditions because of intensified northwest monsoon at the end of the Holocene climatic optimum caused a regional desertion by the arable farming communities and the invasion of the nomads in the northern part of the Loess Plateau from ca. 3600 a BP during the Bronze Age. Monsoonal climatic change and the resultant pedogenic change dramatically affected the cultural development over the Loess Plateau during the Holocene.

  2. Rice blast disease in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice is an important agricultural commodity in Texas, with an economic impact of more than $1 billion annually. Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseases in rice. Texas Rice Belt provides a warm, humid climate favorable for the infection and reproduction of M....

  3. Rice and red rice interference. II. Rice response to population densities of three red rice (Oryza sativa) ecotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice, which grows taller and produces more tillers than domestic rice and shatters most of its seeds early, is a major weed in many rice-growing areas of the world. Field experiments were conducted at Stuttgart, AR in 1997 and 1998 to evaluate the growth response of the Kaybonnet (KBNT) rice cul...

  4. Herbicide contamination and dispersion pattern in lowland springs.

    PubMed

    Laini, Alex; Bartoli, Marco; Lamastra, Lucrezia; Capri, Ettore; Balderacchi, Matteo; Trevisan, Marco

    2012-11-01

    Herbicides reduce the diversity of flora and fauna in freshwater ecosystems and also contaminate groundwater due to leaching. Herbicide contamination can be a serious threat for all groundwater-dependent ecosystems (GDE), altering their chemical and biological quality. Successful management to protect GDE is dependent on detailed knowledge of the hydrogeological and hydrochemical features of the surrounding environment. We consider the possible diffuse contamination by herbicides of groundwater and of GDE as lowland springs, semi-artificial ecosystems with elevated biodiversity. The main objectives of the present work were thus: (1) to map herbicide contamination in lowland springs, (2) to evaluate the potential risk for biota and (3) to quantify the extent of the area from which the herbicide use can affect the water quality of lowland springs. In June and August 2009, nearly 23 springs within the Po River Plain (Northern Italy) were sampled and analyzed for five herbicides used to control weeds in maize. Hydrogeological properties, half-lives of the herbicides and their concentrations in both groundwater and springs were used to quantify the area from which the contamination could originate. Such evaluation was performed by means of GIS techniques. Terbuthylazine were the only herbicide found, together with its metabolite desethylterbuthylazine. In 16 out of 84 measurements, their concentrations were above the threshold for drinking water; however, they were always below the ecotoxicological end-points of aquatic flora and fauna. Spatial analyses reveal that the theoretical area from which herbicides can contaminate spring water is within a distance varying between a few and 1800 m. Our findings indicate that conservation plans should focus on the fields adjacent to or surrounding the springs and should address the optimization of irrigation practices, restoration of buffer strips, crop rotation and in general more sustainable agricultural practices in the

  5. Exchange of nitrous oxide within the Hudson Bay lowland

    NASA Technical Reports Server (NTRS)

    Schiller, C. L.; Hastie, D. R.

    1994-01-01

    The source strength of atmospheric trace gases from natural ecosystems must be quantified in order to assess the effect of such inputs on the background tropospheric chemistry. A static chamber technique and a gas exchange technique were used to determine the emissions of nitrous oxide from five sites within the Hudson Bay Lowland, as part of the Northern Wetland Study. Two mechanisms, one diffusive and the other episodic, were found likely to be responsible for the emissions of nitrous oxide. The annual diffusive flux ranged from -3.8 mg(N2O)/sq m in a treed bog to 7.9 mg(N2O)/sq m in an open fen. The addition of the episodic flux, increased this range to -2.1 mg(N2O)/sq m and 18.5 mg(N2O)/sq m respectively. These episodic emissions occurred in from 2.5% to 16.7% of the samples during the late summer peak emission period. Since the gas exchange rate could not detect the episodic emissions, it was found to be a poor method for water emission rate determination within the wetland. LANDSAT-Thermatic Mapper (TM) imagery was used to scale the emissions, from the chamber level to an integrated average over the entire Hudson Bay Lowland. The total emission rate of N2O from the Hudson Bay Lowland, was determined to be 1.2 Gg(N2O)/year, of which 80% was attributed to episodic emissions.

  6. Prone to fix: Resilience of the active nitrogen-fixing rice root microbiome

    NASA Astrophysics Data System (ADS)

    Hurek, Thomas; Sabale, Mugdha; Sarkar, Abhijit; Pees, Tobias; Reinhold-Hurek, Barbara

    2016-04-01

    Due to water consumption, many lowland rice areas in Asia are undergoing a transition that involves adoption of new management strategies, with crop rotations encompassing a non-flooded crop, including maize. Shifting from flooded to non-flooded cropping is likely to affect microbial nitrogen cycling. For analysis of the root-associated microbiome of rice and maize in response to flooding or nitrogen fertilizer, we combine methods of microbial ecology (Next-Generation sequencing of amplicons), and a reductionist approach with pure cultures of the endophytic diazotroph Azoarus sp.. Field plots of the ICON project (Introducing non-flooded crops in rice-dominated landscapes: Impact on Carbon, nitrogen and water budgets) at the International Rice Research Institute in the Philippines were analyzed. Root-associated activity of nitrogenase gene expression was assessed by quantitative RT-PCR of nifH. For rice, expression levels were surprisingly stable, in response to non-flooded versus flooded conditions, or in response to conventional nitrogen fertilizer applications versus lack of N-fertilizer. In contrast, the active diazotrophic population of maize roots was not resistant to N-fertilization, nifH expression strongly decreased. Concordant changes in the diazotrophic resident or active communities were detected by nifH amplicon sequence analysis, based on bacterial DNA or mRNA, respectively. For high-resolution analyses of the endobiome in gnotobiotic culture, we developed a dual fluorescence reporter system for Azoarcus sp. BH72 which allows to quantify and visualize epi- and endophytic gene expression by concfocal microscopy (CLSM). This allowed us to demonstrate sites of active nitrogen fixation (gene expression) in association with rice roots. We confirmed that at low nitrogen fertilizer levels, endophytic nifH gene expression persisted in rice roots, while it was repressed in maize roots. This supports our observation of remarkable stability of nitrogen fixation

  7. Estimated fumonisin exposure in Guatemala is greatest in consumers of lowland maize

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize samples (n=396) were collected from fields in Guatemala from 2000 to 2003. Maize from the lowlands (1200 m). Approximately 78% of the lowland samples collected at harvest in 2002 contained >0.3 ug/g of fumonisin B1, whereas, onl...

  8. 7 CFR 868.310 - Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled Rice. (See also Â... classes Long Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled Rice...) (percent) Chalky kernels 1,2 In long grain rice (percent) In medium or short grain rice (percent)...

  9. Modelling field scale water partitioning using on-site observations in sub-Saharan rainfed agriculture

    NASA Astrophysics Data System (ADS)

    Makurira, H.; Savenije, H. H. G.; Uhlenbrook, S.

    2010-04-01

    Smallholder rainfed farming systems generally realise sub-optimal crop yields which are largely attributed to dry spell occurrences during crop growth stages. However, through the introduction of appropriate farming practices, it is possible to substantially increase yield levels even with little and highly variable rainfall. The presented results follow research conducted in the Makanya catchment in northern Tanzania where gross rainfall amounts to less than 400 mm/season which is insufficient to support staple food crops (e.g. maize). The yields from farming system innovations (SIs), which are basically alternative cultivation techniques, are compared against traditional farming practices. The SIs tested in this research are runoff harvesting used in combination with in-field trenches and soil bunds (fanya juus). These SIs aim to reduce soil and nutrient loss from the field and, more importantly, promote in-field infiltration and water retention. Water balance components have been observed in order to study water partitioning processes for the "with" and "without" SI scenarios. Based on rainfall, soil evaporation, transpiration, runoff and soil moisture measurements, a water balance model has been developed to simulate soil moisture variations over the growing season. Simulation results show that, during the field trials, the average productive transpiration flow ranged between 1.1-1.4 mm d-1 in the trial plots compared to 0.7-1.0 mm d-1 under traditional tillage practice. Productive transpiration processes accounted for 23-29% while losses to deep percolation accounted for 33-48% of the available water. The field system has been successfully modelled using the spreadsheet-based water balance 1-D model. Conclusions from the research are that the SIs that were tested are effective in enhancing soil moisture retention at field scale and that diversions allow crop growth moisture conditions to be attained with early rains. From the partitioning analysis, it is also

  10. Using LiDAR to characterize logjams in lowland rivers

    NASA Astrophysics Data System (ADS)

    Abalharth, Mahdi; Hassan, Marwan A.; Klinkenberg, Brian; Leung, Vivian; McCleary, Richard

    2015-10-01

    Logjams significantly influence watershed hydrology, flow regime, channel morphology and stability, and processes in lowland rivers. Consequently, logjams play a major role in the existence and conservation of the riparian and aquatic ecosystems along major waterways. In this paper, we attempt to detect and quantify logjams in river channels using LiDAR technology in conjunction with traditional fieldwork. To the best of our knowledge, LiDAR-based analysis has not been used to characterize logjams in streams. Overall, when applied in a lowland river environment, LiDAR-based analysis demonstrates a comprehensive solution for detecting logjams in relation to the fieldwork, with a low rate of omission. A filtered approach predicted the presence of 95% of fieldwork-reported logjams (a 5% rate of omission), but also identified six logjams not identified in the field (a 10% rate of commission). A nonfiltered approach identified 87% of field-reported logjams, producing a 13% rate of omission and a 6.7% rate of commission. Dimension measurements were more consistent in the filtered LiDAR approach, showing 53%, 34%, and 90% of R2 improvements for the length, width, and height, respectively, over the unfiltered LiDAR values. As vegetation cover hindered accurate delineation of logjam boundaries by LiDAR, field and LiDAR measurements of nonvegetation-obstructed logjams were more highly correlated than the field and LiDAR measurements of partially and completely vegetation-obstructed logjams.

  11. Bayesian phylogeography of the Arawak expansion in lowland South America

    PubMed Central

    Walker, Robert S.; Ribeiro, Lincoln A.

    2011-01-01

    Phylogenetic inference based on language is a vital tool for tracing the dynamics of human population expansions. The timescale of agriculture-based expansions around the world provides an informative amount of linguistic change ideal for reconstructing phylogeographies. Here we investigate the expansion of Arawak, one of the most widely dispersed language families in the Americas, scattered from the Antilles to Argentina. It has been suggested that Northwest Amazonia is the Arawak homeland based on the large number of diverse languages in the region. We generate language trees by coding cognates of basic vocabulary words for 60 Arawak languages and dialects to estimate the phylogenetic relationships among Arawak societies, while simultaneously implementing a relaxed random walk model to infer phylogeographic history. Estimates of the Arawak homeland exclude Northwest Amazonia and are bi-modal, with one potential homeland on the Atlantic seaboard and another more likely origin in Western Amazonia. Bayesian phylogeography better supports a Western Amazonian origin, and consequent dispersal to the Caribbean and across the lowlands. Importantly, the Arawak expansion carried with it not only language but also a number of cultural traits that contrast Arawak societies with other lowland cultures. PMID:21247954

  12. Geohydrology of the lowland lakes area, Anchorage, Alaska

    USGS Publications Warehouse

    Zenone, Chester

    1976-01-01

    Unconsolidated deposits, chiefly of glacial origin, make up the surficial geologic materials in the Anchorage lowland lakes area , the western part of the Anchorage glacial outwash plain. Postglacial accumulation of peat, commonly 5 to 10 feet thick, and the presence of ground water at or very near the surface combine to create the swamp-muskeg terrane of much of the area. Deeper, confined ground water is also present beneath thick silt and clay layers that underlie the surficial deposits. Domestic water supply for the lowland lakes area is provided largely by public-supply wells completed in the deep, confined aquifers. No large perennial streams traverse the area, thus streamflow is not a major parameter in the area 's natural water balance. The major uses of surface water are recreational, including fishing and boating at several of the larger lakes, and private and commercial aircraft operations at Hood-Spenard Lakes floatplane base. The hydrology and water balance of these lakes is complex. Water levels in some lakes appear to be closely related to adjacent ground-water levels. Other lakes are evidently perched above the local water table. The relation of lake level to adjacent ground-water level may vary along the shoreline of a single lake. The effect of residential development practices on lake basin water balance is not completely understood. At Sand Lake, the largest lake in this area of rapid urbanization, the water level has declined about 6 feet since the early 1960's. (Woodard-USGS)

  13. The puzzling origin of the Martian Northern Lowlands.

    NASA Astrophysics Data System (ADS)

    Altieri, F.; Carrozzo, G.; Carli, C.; Geminale, A.; Bellucci, G.

    Surface studies of the northern lowlands of Mars have shown that this region has undergone a complex history including volcanism, sedimentary deposition and secondary modification by climate change. Despite these analyses, the origin and the evolution of this region are still debated. No clear and definitive evidences have been found so far to conclude whether these plains were formed by a giant impact, were once covered by an ocean or were filled by a large quantity of lavas. In the visible and infrared spectral range, the northern lowlands differ from southern terrains in the NIR negative slope while they exhibit VNIR spectra similar to the southern pyroxene-rich areas (Carrozzo et al., 2012). These observations, combined with both recent detection of mafic minerals at higher spatial resolution by CRISM (Salvatore et al., 2010) and recent results of Horgan and Bell (2012), supports that their mineralogy is linked to weathered basalts with a glassy component. In addition to this, the spectral similarity of Acidalia area with the northern circumpolar sand dunes, apart from the hydration features, suggests that the weathering processes that took place there could be related to past glacial activity, in agreement with superficial morphology showing glacial structures. Aim of this work is to combine the OMEGA mineralogical maps with morphological features (Tanaka et al., 2011) and investigate possible terrestrial analogues in order to give some constrains on the composition and origin of these puzzling Martian terrains.

  14. Modeling a network of turloughs in lowland karst

    NASA Astrophysics Data System (ADS)

    Gill, L. W.; Naughton, O.; Johnston, P. M.

    2013-06-01

    In lowland karst areas of Ireland topographic depressions which get intermittently flooded on an annual cycle via groundwater sources are termed turloughs. These are sites of high ecological interest as they have communities and substrate characteristic of wetlands. The flooding in many turlough basins is due to insufficient capacity of the underground karst system to take increased flows following excessive precipitation events, causing the conduit-type network to surcharge. Continuous water level measurements have been taken in five linked turloughs in the lowland karst area of south Galway over a 3 year period. These water level fluctuations, in conjunction with river inputs and precipitation, were then used to elucidate the hydrogeological controls forming the hydraulic system beneath the ground. A model of the karst network has been developed using a pipe network model with the turloughs represented as ponds. The contribution to the karst network from diffuse flow through the epikarst via the matrix and fracture flow has also been modeled using a combination of an infiltration module and network of permeable pipes. The final model was calibrated against two separate hydrological years and in general provided a good simulation for all of the turloughs water levels particularly for the year with one main filling event. The model also accurately picked up the tidal response observed in these turloughs at shallow depths. The model has been used to predict the groundwater discharge to the coast via the main spring which had not heretofore been possible to measure, being below the sea level.

  15. Multiple abiotic stimuli are integrated in the regulation of rice gene expression under field conditions.

    PubMed

    Plessis, Anne; Hafemeister, Christoph; Wilkins, Olivia; Gonzaga, Zennia Jean; Meyer, Rachel Sarah; Pires, Inês; Müller, Christian; Septiningsih, Endang M; Bonneau, Richard; Purugganan, Michael

    2015-01-01

    Plants rely on transcriptional dynamics to respond to multiple climatic fluctuations and contexts in nature. We analyzed the genome-wide gene expression patterns of rice (Oryza sativa) growing in rainfed and irrigated fields during two distinct tropical seasons and determined simple linear models that relate transcriptomic variation to climatic fluctuations. These models combine multiple environmental parameters to account for patterns of expression in the field of co-expressed gene clusters. We examined the similarities of our environmental models between tropical and temperate field conditions, using previously published data. We found that field type and macroclimate had broad impacts on transcriptional responses to environmental fluctuations, especially for genes involved in photosynthesis and development. Nevertheless, variation in solar radiation and temperature at the timescale of hours had reproducible effects across environmental contexts. These results provide a basis for broad-based predictive modeling of plant gene expression in the field. PMID:26609814

  16. Utility of thermal image sharpening for monitoring field-scale evapotranspiration over rainfed and irrigated agricultural regions

    NASA Astrophysics Data System (ADS)

    Agam, Nurit; Kustas, William P.; Anderson, Martha C.; Li, Fuqin; Colaizzi, Paul D.

    2008-01-01

    The utility of a thermal image sharpening algorithm (TsHARP) in providing fine resolution land surface temperature data to a Two-Source-Model for mapping evapotranspiration (ET) was examined over two agricultural regions in the U.S. One site is in a rainfed corn and soybean production region in central Iowa. The other lies within the Texas High Plains, an irrigated agricultural area. It is concluded that in the absence of fine (sub-field scale) resolution thermal data, TsHARP provides an important tool for monitoring ET over rainfed agricultural areas. In contrast, over irrigated regions, TsHARP applied to kilometer-resolution thermal imagery is unable to provide accurate fine resolution land surface temperature due to significant sub-pixel moisture variations that are not captured in the sharpening procedure. Consequently, reliable estimation of ET and crop stress requires thermal imagery acquired at high spatial resolution, resolving the dominant length-scales of moisture variability present within the landscape.

  17. Deposition by the 2011 Tohoku-oki tsunami on coastal lowland controlled by beach ridges near Sendai, Japan

    NASA Astrophysics Data System (ADS)

    Takashimizu, Yasuhiro; Urabe, Atsushi; Suzuki, Koji; Sato, Yoshiki

    2012-12-01

    A study of the 2011 Tohoku-oki tsunami deposits on the coastal lowland of the Sendai Plain, Japan was carried out along a shore-perpendicular survey line in the Arahama area. Field descriptions and tsunami water depth measurements were complemented by sedimentary analyses, including grain size, grain fabric and diatom analysis. The tsunami deposits show a generally fining-inland trend along the 3.4 km long transect. The depositional facies, grain size analysis and grain fabric data suggest that most of the tsunami deposits were laid down during the tsunami inflow, except at one site. These tsunami deposits are characterized by parallel-laminated or massive sand and silt with pieces of woods, fragments of glass, rip-up mud clasts and an erosional base. Minor backwash deposits overlying the inflow sand layer were only observed on one beach ridge and attributed to the topographic high. Marine diatom species comprised only approximately 2% of the diatom assemblage in tsunami deposits and their content decreased landward. In this study, diatom assemblages were similar in the rice field soil and tsunami layers, suggesting that the muddy fraction of the deposits mainly consists of sediments derived from the tsunami-eroded rice field soil. As a result of soil erosion, the tsunami had a high suspended sediment load. Furthermore, after the first tsunami inundation, seawater left by the tsunami did not drain completely to the sea because of the high coastal beach ridge and/or coastal subsidence due to the massive earthquake. Therefore, strong tsunami outflows to the sea did not occur and these areas were covered by mud deposited from stagnant water.

  18. Land, Water and Society in the Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Murtha, T.; French, K.; Duffy, C.; Webster, D.

    2013-12-01

    This paper reports the results of our project investigating the long-term spatial and temporal dynamics of land use management, agricultural decision-making and patterns of resource availability in the tropical lowlands of Central America. Overall, our project combines diachronic environmental simulation with historic settlement pattern survey to address a series of long-standing questions about the coupled natural and human (CNH) landscape history in the Central Maya lowlands (at the UNESCO world heritage site of Tikal in the Maya Biosphere Reserve). The paper describes the preliminary results of our project, including changing patterns of land, water, settlement and political history using climate, soil and hydrologic modeling and time series spatial analysis of population and settlement patterns. The critical period of the study, 1000 BC until the present, begins with dispersed settlements accompanied by widespread deforestation and soil erosion. Population size and density grows rapidly for 800 years, while deforestation and erosion rates decline; however, there is striking evidence of political evolution during this period, including the construction of monumental architecture, hieroglyphic monuments detailing wars and alliances, and the construction of a defensive earthwork feature, signaling political territories and possibly delineating natural resource boundaries. Population decline and steady reforestation followed until more recent migration into the region, which has impacted the biosphere ecology. Building on our previous research regionally and comparative research completed in Belize and Mexico, we are modeling sample periods the 3,000-year landscape history of the region, comparing land and water availability to population distributions and what we know about political history. Simulations are generated using historic climate and land use data, primarily relying on the Erosion Productivity Impact Calculator (EPIC) and the Penn State Integrated

  19. Resequencing rice genomes: an emerging new era of rice genomics.

    PubMed

    Huang, Xuehui; Lu, Tingting; Han, Bin

    2013-04-01

    Rice is a model system for crop genomics studies. Much of the early work on rice genomics focused on analyzing genome-wide genetic variation to further understand rice gene functions in agronomic traits and to generate data and resources for rice research. The advent of next-generation high-throughput DNA sequencing technologies and the completion of high-quality reference genome sequences have enabled the development of sequencing-based genotyping and genome-wide association studies (GWAS) that have significantly advanced rice genetics research. This has led to the emergence of a new era of rice genomics aimed at bridging the knowledge gap between genotype and phenotype in rice. These technologies have also led to pyramid breeding through genomics-assisted selection, which will be useful in breeding elite varieties suitable for sustainable agriculture. Here, we review the recent advances in rice genomics and discuss the future of this line of research. PMID:23295340

  20. The influence of nitrogen fertiliser rate and crop rotation on soil methane flux in rain-fed potato fields in Wuchuan County, China.

    PubMed

    Wang, Liwei; Pan, Zhihua; Xu, Hui; Wang, Cheng; Gao, Lin; Zhao, Peiyi; Dong, Zhiqiang; Zhang, Jingting; Cui, Guohui; Wang, Sen; Han, Guolin; Zhao, Hui

    2015-12-15

    As one of the important greenhouse gases, the characteristics and principles of methane exchange characteristics in cultivated lands have become hot topics in current climate change research. This study examines the influences of nitrogen fertilisation, temperature and soil water content on methane exchange characteristic and methane exchange functional gene-pmoA gene abundance based on experimental observations of methane exchange fluxes using the static chamber-gas chromatographic method and measurements of methanotroph gene copy numbers in three growing periods by real-time PCR in rain-fed potato fields. The results indicate that the rain-fed potato fields were a CH4 sink with an average annual methane absorption (negative emission) of 940.8±103.2 g CH4-C/ha/year. The cumulative methane absorption first exhibited flat and subsequently increasing trend with the increase of nitrogen fertilisation from 0~135 kg N·ha(-1). Methane cumulative absorption significantly increased with the increase of temperature when temperatures were below 19.6 °C. Methane oxidation capacity (methanotroph pmoA gene copy numbers) showed an increasing and subsequently decreasing trend with the increase of soil moisture. Crop rotation was observed to increase the methane absorption in rain-fed potato fields and nearly one time higher than that under continuous cropping. A mechanism concept model of the methane exchange in rain-fed potato fields was advanced in this paper. PMID:26282743

  1. About climate variabilitiy leading the hydric condition of the soil in the rainfed region of Argentina

    NASA Astrophysics Data System (ADS)

    Pántano, V. C.; Penalba, O. C.

    2013-05-01

    Extreme events of temperature and rainfall have a socio-economic impact in the rainfed agriculture production region in Argentina. The magnitude of the impact can be analyzed through the water balance which integrates the characteristics of the soil and climate conditions. Changes observed in climate variables during the last decades affected the components of the water balance. As a result, a displacement of the agriculture border towards the west was produced, improving the agricultural production of the region. The objective of this work is to analyze how the variability of rainfall and temperature leads the hydric condition of the soil, with special focus on extreme events. The hydric conditions of the soil (HC= Excess- Deficit) were estimated from the monthly water balance (Thornthwaite and Mather method, 1957), using monthly potential evapotranspiration (PET) and monthly accumulated rainfall (R) for 33 stations (period 1970-2006). Information of temperature and rainfall was provided by National Weather Service and the effective capacity of soil water was considered from Forte Lay and Spescha (2001). An agricultural extreme condition occurs when soil moisture and rainfall are inadequate or excessive for the development of the crops. In this study, we define an extreme event when the variable is less (greater) than its 20% and 10% (80% and 90%) percentile. In order to evaluate how sensitive is the HC to water and heat stress in the region, different conditional probabilities were evaluated. There is a weaker response of HC to extreme low PET while extreme low R leads high values of HC. However, this behavior is not always observed, especially in the western region where extreme high and low PET show a stronger influence over the HC. Finally, to analyze the temporal variability of extreme PET and R, leading hydric condition of the soil, the number of stations presenting extreme conditions was computed for each month. As an example, interesting results were

  2. Assessment of Predictability of Philippine Rice Production with Climate Information

    NASA Astrophysics Data System (ADS)

    Koide, N.; Robertson, A. W.; Qian, J.; Ines, A. M.

    2010-12-01

    El Niño Southern Oscillation is the most influential factor on the Philippine climate and has measurable impacts on rice production. The previous studies suggested potential of climate information for prediction of the rice production. For example, Roberts et al. (2009) showed the statistically significant relationship of dry-season rice production in Luzon with Niño sea surface temperature anomalies (SSTA) averaged over the Niño 3.4 region (5°N-5°S, 120°-170°W) for July to September of the year before the harvest. However, the predictive skills of climate information for rice production have not been previously analyzed yet. Thus, we have conducted the assessment of predictive skills of one uncoupled general circulation models (GCMs) (ECHAM-CA) and two coupled GCMs (ECHAM-MOM, and ECHAM-CFS), as well as those of Niño 3.4 SSTAs and the volume of water warmer than 20°C (WWV) in the equatorial Pacific Ocean (5°N-5°S, 120°E to 80°W), based on cross validation with MLR, PCR, CCA. The result clearly shows high potential of these climate information as a tool for prediction of rice production with sufficient lead time for decision makers. Detailed results are as below. Dry Season Dry season rice production of the Philippines of both irrigation and rainfed systems significantly depend on rainfall in OND of the year before the harvest (same results were found by Roberts et al. (2009)). Two coupled GCMs have high predictive skills for dry-season rice production of the Philippines with six months lead time (six months before the beginning of the harvest). In addition, we found that WWV plus zonal wind anomalies over an equatorial west Pacific also has similar predictive skills to those of these coupled GCMs. On the other hand, the uncoupled GCM has high predictive skills only with a few months lead time similar to predictive skills of Niño 3.4 SSTAs. Predictive skills at regional levels are generally lower than that for the Philippines. Many regions in Mindanao

  3. Kax and kol: Collapse and resilience in lowland Maya civilization

    PubMed Central

    Dunning, Nicholas P.; Beach, Timothy P.; Luzzadder-Beach, Sheryl

    2012-01-01

    Episodes of population loss and cultural change, including the famous Classic Collapse, punctuated the long course of Maya civilization. In many cases, these downturns in the fortunes of individual sites and entire regions included significant environmental components such as droughts or anthropogenic environmental degradation. Some afflicted areas remained depopulated for long periods, whereas others recovered more quickly. We examine the dynamics of growth and decline in several areas in the Maya Lowlands in terms of both environmental and cultural resilience and with a focus on downturns that occurred in the Terminal Preclassic (second century Common Era) and Terminal Classic (9th and 10th centuries CE) periods. This examination of available data indicates that the elevated interior areas of the Yucatán Peninsula were more susceptible to system collapse and less suitable for resilient recovery than adjacent lower-lying areas. PMID:22371571

  4. Methane emissions from wetlands, southern Hudson Bay lowland

    SciTech Connect

    Moore, T.R.; Heyes, A.; Roulet, N.T.

    1994-01-20

    This article describes the monitoring of methane emissions at 39 wetland ecosystem sites in the Hudson Bay Lowland. The study sites were located along a transect from the James Bay Coast at the tip of the Hudson Bay to Kinosheo Lake near Moosonee, Ontario, Canada. Measurements of methane flux were made using a static chamber technique. Weak statistical relationships were noted at each site between the daily methane flux rate, ground-water depth, and peat temperatures. On a regional scale, a significant correlation was noted over the complete range of sites between the seasonal methane flux and the average position of the ground-water table. Other observations are also described. 51 refs., 7 figs., 4 tabs.

  5. Crash and rebound of indigenous populations in lowland South America.

    PubMed

    Hamilton, Marcus J; Walker, Robert S; Kesler, Dylan C

    2014-01-01

    Lowland South America has long been a battle-ground between European colonization and indigenous survival. Initial waves of European colonization brought disease epidemics, slavery, and violence that had catastrophic impacts on indigenous cultures. In this paper we focus on the demography of 238 surviving populations in Brazil. We use longitudinal censuses from all known indigenous Brazilian societies to quantify three demographic metrics: 1) effects of European contact on indigenous populations; 2) empirical estimates of minimum viable population sizes; and 3) estimates of post-contact population growth rates. We use this information to conduct population viability analysis (PVA). Our results show that all surviving populations suffered extensive mortality during, and shortly after, contact. However, most surviving populations exhibit positive growth rates within the first decade post-contact. Our findings paint a positive demographic outlook for these indigenous populations, though long-term survival remains subject to powerful externalities, including politics, economics, and the pervasive illegal exploitation of indigenous lands. PMID:24687096

  6. Soil phosphorus and the ecology of lowland tropical forests

    NASA Astrophysics Data System (ADS)

    Turner, Ben

    2016-04-01

    In this presentation I will explore the extent to which phosphorus influences the productivity, diversity, and distribution of plant species in tropical forests. I will highlight the range of soils that occur in tropical forests and will argue that pedogenesis and associated phosphorus depletion is a primary driver of forest diversity over long timescales. I will draw on data from a regional-scale network of forest dynamics plots in Panama to show that tree species distributions are determined predominantly as a function of dry season intensity and soil phosphorus availability, and will suggest potential mechanistic explanations for this pattern in relation to phosphorus acquisition. Finally, I will present observational and experimental evidence from Panama to show how phosphorus, nitrogen, and potassium, limit plant productivity and microbial communities on strongly-weathered soils in the lowland tropics.

  7. Lowland forest loss in protected areas of Indonesian Borneo.

    PubMed

    Curran, L M; Trigg, S N; McDonald, A K; Astiani, D; Hardiono, Y M; Siregar, P; Caniago, I; Kasischke, E

    2004-02-13

    The ecology of Bornean rainforests is driven by El Niño-induced droughts that trigger synchronous fruiting among trees and bursts of faunal reproduction that sustain vertebrate populations. However, many of these species- and carbon-rich ecosystems have been destroyed by logging and conversion, which increasingly threaten protected areas. Our satellite, Geographic Information System, and field-based analyses show that from 1985 to 2001, Kalimantan's protected lowland forests declined by more than 56% (>29,000 square kilometers). Even uninhabited frontier parks are logged to supply international markets. "Protected" forests have become increasingly isolated and deforested and their buffer zones degraded. Preserving the ecological integrity of Kalimantan's rainforests requires immediate transnational management. PMID:14963327

  8. Validating Ancient Age of the Buried Floor of the Northern Lowlands, Mars

    NASA Technical Reports Server (NTRS)

    Buczkowski, D. L.; Frey, H. V.; Roark, J. H.; McGill, G. E.

    2004-01-01

    Hesperian and Amazonian plains units cover the northern lowlands but little is known about what this surface covers. Models for the creation of the lowlands and the dichotomy boundary implement mechanisms which vary from internal processes, such as plate tectonics or first-order mantle convection, to external processes, such as a single large impact or multiple impacts. Different models require different time scales for low-land formation; determining the age of the buried low-land surface would help constrain the formation models. The Mars Orbiting Laser Altimeter (MOLA) has yielded a high-precision, topographic gridded data set that reveals the presence of Quasi-Circular Depressions (QCDs) in both the southern highlands and the northern lowlands. Most of these roughly circular depressions have no corresponding visible structural feature on the surface. It is proposed that these QCDs are the surface representation of buried impact craters. Based on this assumption, cumulative number vs. diameter curves were constructed, which placed the age of the buried surface of the northern lowlands in the Early or pre-Noachian. A Noachian basement is supported by the remnants of large craters and multi-ring basins discovered in earlier research, but the QCDs provide the first evidence of this for the entire lowland. Constraining the age of the basement floor to the earliest Noachian, however, would require that the process that formed the northern lowlands either occurred in the early Noachian or involves removal of material from the bottom of the crust without destroying the previously formed craters to achieve the modeled crustal thinning. But can we establish that the QCDs do in fact represent buried impact craters, and thus validate an Early Noachian age for the buried lowland floor?

  9. Lake Tapps tephra: An early Pleistocene stratigraphic marker in the Puget Lowland, Washington

    USGS Publications Warehouse

    Westgate, J.A.; Easterbrook, D.J.; Naeser, N.D.; Carson, R.J.

    1987-01-01

    The rhyolitic Lake Tapps tephra was deposited about 1.0 myr ago, shortly after culmination of the early phase of the Salmon Springs Glaciation in the Puget Lowland. It is contained within sediments that were deposited in ponds or lakes in front of the reteating glacier. An herb-dominated tundra existed in the southern Puget Lowland at that time. Lake Tapps tephra is most likely the product of an eruption that in part was phreatomagmatic. It forms an early Pleistocene stratigraphic marker across the southern sector of the Puget Lowland and provides a link between Puget lobe sediments of the Cordilleran Ice Sheet and sediments deposited by Olympic alpine glaciers. ?? 1987.

  10. Seasat synthetic aperture radar ( SAR) response to lowland vegetation types in eastern Maryland and Virginia.

    USGS Publications Warehouse

    Krohn, M.D.; Milton, N.M.; Segal, D.B.

    1983-01-01

    Examination of Seasat SAR images of eastern Maryland and Virginia reveals botanical distinctions between vegetated lowland areas and adjacent upland areas. Radar returns from the lowland areas can be either brighter or darker than returns from the upland forests. Scattering models and scatterometer measurements predict an increase of 6 dB in backscatter from vegetation over standing water. This agrees with the 30-digital number (DN) increase observed in the digital Seasat data. The density, morphology, and relative geometry of the lowland vegetation with respect to standing water can all affect the strength of the return L band signal.-from Authors

  11. Regional Studies of Highland-Lowland Age Differences Across the Mars Crustal Dichotomy Boundary

    NASA Technical Reports Server (NTRS)

    Frey, H. V.; DeSoto, G. E.; Lazrus, R. M.

    2005-01-01

    Regional differences in crater retention ages (CRAs) across the Mars dichotomy boundary are compared to the global highland-lowland age difference previously determined from visible and buried impact basins based on MOLA-derived Quasi-Circular Depressions (QCDs). Here Western Arabia (WA) is compared with Ismenius Lacus (IL). We find the buried lowlands in the two regions have total CRAs essentially identical to the global average. Even more intriguing, the WA cratered terrain appears to have a CRA like that of the adjacent buried lowlands,

  12. Development of a real-time hydrological cycle - rice growth coupled simulation system as a tool for farmers' decision making in an ungauged basin in Cambodia for the better agricultural water resources management

    NASA Astrophysics Data System (ADS)

    Tsujimoto, K.; Ohta, T.; Yasukawa, M.; Koike, T.; Kitsuregawa, M.; Homma, K.

    2013-12-01

    The entire country of Cambodia depends on agriculture for its economy. Rice is the staple food, making it the major agricultural product (roughly 80% of total national production). The target area of this study is western Cambodia, where rice production is the greatest in the country and most land is rainfed. Since most farmers rely only on their (non-science-based) experience, they would not adjust to changing rainfall and degraded water resources under climate change, so food security in the region would be seriously threatened (Monichoth et al., 2013). Under this condition, irrigation master plans are being considered by several ODA projects. This study aims to contribute to the design of such irrigation plans through the development of a real-time hydrological cycle - rice growth coupled simulation system. The purpose of the development of this system is to support decision making 1) for determining the necessary agricultural water resources and 2) for allocating limited water resources to various sectors. Rice growing condition as affected by water stress due to the water shortage is supposed to be shown for both of the cases with and without irrigation for several rainfall patterns. A dynamically coupled model of a distributed hydrological model (WEB-DHM., Wang et al., 2009) and a rice growth model (SIMRIW-rainfed, Homma et al., 2009) has been developed with a simple irrigation model. The target basin, a small basin in western Cambodia, is basically an ungauged basin and the model was validated by soil moisture, LAI, dry matter production of the rice crop, and rice yield, using both intensive field observation and satellite observations. Calibrating hourly satellite precipitation dataset (GSMaP/NRT) using ground rain gauges, hydrological cycle (soil moisture at three layers, river discharge, irrigatable water amount, water level of each paddy field, water demand of each paddy field, etc.) and rice growth (LAI, developmental index of the rice crop, dry matter

  13. Comparing the water-use-efficiency of maize and biomass sorghum grown in the rain-fed, Midwestern US.

    NASA Astrophysics Data System (ADS)

    Roby, M.; VanLoocke, A. D.; Heaton, E.; Miguez, F.; Salas Fernandez, M.

    2015-12-01

    Uncertainty in the quantity and timing of precipitation in a changing climate, combined with an increased demand for non-grain ethanol feedstock, may necessitate expanding the production of more water-use-efficient and less drought sensitive crops for biofuel applications. Research suggests that biomass sorghum [Sorghum bicolor (L.) Moench] is more drought tolerant and can produce more biomass than maize in water-limiting environments; however, sorghum water use data are scarce for the rain-fed Midwestern US. To address this gap, a replicated (n=3) side-by-side trial was established in Ames, Iowa to determine cumulative water use and water-use-efficiency of maize and biomass sorghum throughout the 2014 and 2015 growing seasons. Latent heat flux was estimated using the residual in the energy balance technique. Continuous micrometeorological measurements were supplemented by periodic measurements of leaf area index (LAI) and above-ground biomass. Water use (WU), aboveground biomass, and water-use-efficiency (WUE) were found to be similar for both crop types in 2014; data from the 2015 growing season are currently being processed. In 2015, leaf gas exchange measurements were made with a portable photosynthesis instrument. Photosynthetic parameters from gas exchange measurements will be implemented in a semi-mechanistic crop model (BioCro) as a method for scaling WUE estimates across the rain-fed Midwestern US driven with future climate projections. This research highlights the importance of understanding the potential effects of expanding biomass sorghum production on the hydrologic cycle of the Midwestern, US.

  14. Improving feeding systems for sheep in a Mediterranean rain-fed cereals/livestock area of Morocco.

    PubMed

    Guessous, F; Rihani, N; Kabbali, A; Johnson, W L

    1989-11-01

    In rain-fed cereal-producing areas of Morocco, stubble and straw from barley and wheat and forage grazed from fallow lands are important feeds for sheep. Supplementation to maintain BW of ewes pregnant while grazing stubble, methods to improve utilization of straw, annual forage legumes to complement grazing of fallow land, and by-product feeds in diets for weaned lambs have been tested in collaborative research trials. Pregnant ewes grazing cereal stubble for 10 to 12 wk at a modest stocking rate and unsupplemented, or at a heavier stocking rate and supplemented after 5 wk, gained about 3 kg; most of the gain occurred in wk 1 to 4 due to intake of residual scattered grain. Following the stubble-grazing period (coincident with late gestation), straw plus an energy supplement alone resulted in low lamb birth weight and survivability. Urea treatment increased N content of straw and holds potential. After the onset of winter rains, self-reseeding annual legume (Medicago spp.) pastures allowed lactating Timahdit ewes to gain 4 kg during 90 d postpartum. Their suckling lambs gained 260 g/d, thus doubling the weight of lamb weaned per ewe compared with those grazing unimproved fallow. Confined growing lambs fed diets with 40% sugarbeet pulp or 20% carob meal gained more than 200 g/d, reducing the time needed to reach market weight. These results demonstrate that marked improvements in performance and efficiency of sheep in Mediterranean rain-fed cereal/livestock systems are possible using locally available resources. PMID:2687218

  15. Mars, highlands-lowlands: Viking contributions to mariner relative age studies

    USGS Publications Warehouse

    Scott, D.H.

    1978-01-01

    Stratigraphic relations between lowland plains and highlands, two major types of Martian geologic-terrain units, were not directly distinguishable on Mariner-9 images. Morphologic characteristics and crater densities suggested that the lava plains beneath their eolian cover were younger than adjacent highland rocks, which form a plateau bounded in many places by highly dissected escarpments. Alternatively, the lowland plains could be the older unit and represent a broad erosional surface exhumed by southward retreat of the highlands along their frontal scarp. Viking photos across five areas of the highland-lowland boundary, however, tend to confirm the younger age of the plains-forming lava flows. A time interval of several hundred million years probably occurred between the retreat of the highland scarp and its latest embayment by lava extrusions in the lowlands. ?? 1978.

  16. Effect of rice variety and nutrient management on rice productivity in organic rice system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Demand for organic rice has been increasing for decades. However, the information on sustainable organic rice production systems is still lacking. The objective of this study was to investigate the effects of soil amendment products, nitrogen rate, and variety on rice grain yield, yield components, ...

  17. Survey of arsenic and its speciation in rice products such as breakfast cereals, rice crackers and Japanese rice condiments.

    PubMed

    Sun, Guo-Xin; Williams, Paul N; Zhu, Yong-Guan; Deacon, Claire; Carey, Anne-Marie; Raab, Andrea; Feldmann, Joerg; Meharg, Andrew A

    2009-04-01

    Rice has been demonstrated to be one of the major contributors to arsenic (As) in human diets in addition to drinking water, but little is known about rice products as an additional source of As exposure. Rice products were analyzed for total As and a subset of samples were measured for arsenic speciation using high performance liquid chromatography interfaced with inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). A wide range of rice products had total and inorganic arsenic levels that typified those found in rice grain including, crisped rice, puffed rice, rice crackers, rice noodles and a range of Japanese rice condiments as well as rice products targeted at the macrobiotic, vegan, lactose intolerant and gluten intolerance food market. Most As in rice products are inorganic As (75.2-90.1%). This study provides a wider appreciation of how inorganic arsenic derived from rice products enters the human diet. PMID:18775567

  18. RICE IDENTITY TESTING USING DNA MARKER ANALYSIS OF PROCESSEDOR ARCHIVED RICE TISSUE AND RICE-INGREDIENT FOODS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The highly regarded reputation of USA rice in the world marketplace rice has been achieved by delivering rice and rice products that meet rigorous standards of uniformity and quality. In this regard, seed dealers, farmers, millers, and processors are concerned that the rice seed they are handling is...

  19. Stunt or elongate? Two opposite strategies by which rice adapts to floods.

    PubMed

    Nagai, Keisuke; Hattori, Yoko; Ashikari, Motoyuki

    2010-05-01

    Expansion of habitat is important for the perpetuation of species. In particular, plants which are sedentary must evolve specialized functions to adapt itself to new environment. Deepwater rice is cultivated mainly in the lowland areas of South and Southeast Asia that are flooded during the rainy season. The internodes of deepwater rice elongates in response to increasing water level to keep its leaves above the water surface and avoid anoxia. This elongation is stimulated by ethylene-regulated genes, Snorkel1 and Snorkel2. In contrast, when a flash flood occurs at the seedling stage, submergence-tolerant rice, which carries Submergence-1A, remains stunted and survives in water for a few weeks to avoid the energy consumption associated with plant elongation, and restarts its growth using its conserved energy after the water recedes. Interestingly, both Snorkel genes and Submergence-1A encode ethylene-responsive factor-type transcription factor and are connected to gibberellin biosynthesis or signal transduction. However, deepwater and submergence-tolerant rice seem to have opposite flooding response; namely, escape by elongation or remain stunted under water until flood recedes. PMID:20354754

  20. Identification of drought-responsive genes in roots of upland rice (Oryza sativa L)

    PubMed Central

    Rabello, Aline R; Guimarães, Cléber M; Rangel, Paulo HN; da Silva, Felipe R; Seixas, Daniela; de Souza, Emanuel; Brasileiro, Ana CM; Spehar, Carlos R; Ferreira, Márcio E; Mehta, Ângela

    2008-01-01

    Background Rice (Oryza sativa L.) germplasm represents an extraordinary source of genes that control traits of agronomic importance such as drought tolerance. This diversity is the basis for the development of new cultivars better adapted to water restriction conditions, in particular for upland rice, which is grown under rainfall. The analyses of subtractive cDNA libraries and differential protein expression of drought tolerant and susceptible genotypes can contribute to the understanding of the genetic control of water use efficiency in rice. Results Two subtractive libraries were constructed using cDNA of drought susceptible and tolerant genotypes submitted to stress against cDNA of well-watered plants. In silico analysis revealed 463 reads, which were grouped into 282 clusters. Several genes expressed exclusively in the tolerant or susceptible genotypes were identified. Additionally, proteome analysis of roots from stressed plants was performed and 22 proteins putatively associated to drought tolerance were identified by mass spectrometry. Conclusion Several genes and proteins involved in drought-response, as well as genes with no described homologs were identified. Genes exclusively expressed in the tolerant genotype were, in general, related to maintenance of turgor and cell integrity. In contrast, in the susceptible genotype, expression of genes involved in protection against cell damage was not detected. Several protein families identified in the proteomic analysis were not detected in the cDNA analysis. There is an indication that the mechanisms of susceptibility to drought in upland rice are similar to those of lowland varieties. PMID:18922162

  1. Duration and Frequency Analysis of Lowland Flooding in Western Murfreesboro, Rutherford County, Tennessee, 1998-2000

    USGS Publications Warehouse

    Law, George S.

    2002-01-01

    Periodic flooding occurs at lowlands and sinkholes in and adjacent to the flood plain of the West Fork Stones River in the western part of Murfreesboro, Tennessee. Flooding in this area commonly occurs during the winter months from December through March. The maximum water level that flood waters will reach in a lowland or sinkhole is controlled by the elevation of the land surrounding the site or the overflow outlet. Maximum water levels, independent of overflow from the river, were estimated to be reached in lowlands and sinkholes in the study area every 1 to 4 years. Minor overflow from the West Fork Stones River (less than 1 foot in depth) into the study area has been estimated to occur every 10 to 20 years. Moderate overflow from the river (1 to 2 feet in depth) occurs on average every 20 to 50 years, while major river overflow (in excess of 2 feet in depth) can be expected every 50 years. Rainfall information for the area, and streamflow and water-level measurements from the West Fork Stones River, lowlands, sinkholes, caves, and wells in the study area were used to develop a flood-prone area map, independent of overflow from the river, for the study area. Water-level duration and frequency relations, independent of overflow from the river, were estimated for several lowlands, sinkholes, and wells in the study area. These relations are used to characterize flooding in lowland areas of western Murfreesboro, Rutherford County, Tennessee.

  2. Rice disease management under organic production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interest in organic rice production has increased because of the increased market demand for organic rice. Texas organic rice acreage has constantly increased over the last decade, reaching 32,000 acres in 2012. Texas is now the leading state in organic rice production in the U.S. Organic rice is p...

  3. Organic Rice Production: Challenges and Opportunities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The market demand for organically produced rice has grown steadily with the majority of the acreage now being located in Texas and California. A wide range of organic products are marketed including conventional long and medium grain rice, aromatic or scented rice, rice with colored bran, and rice f...

  4. Exploring Japan through Rice.

    ERIC Educational Resources Information Center

    Wojtan, Linda S.

    1998-01-01

    Explores the role of rice in Japanese culture by presenting historical background and teaching activities in a variety of categories, such as language, sociology, history, and contemporary politics. Suggests teachers create cross-cultural comparisons; for example, the role of corn in the United States. Provides a list of teacher resources. (CMK)

  5. Rice: chemistry and technology.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice has taken center stage this last decade, not only as an important provider of nourishment for the world’s population, but as a grain now recognized as having many unique nutritional and functional attributes with potential to be captured in a multitude of value-added food and non-food applicati...

  6. Tharsis-triggered Flood Inundations of the Lowlands of Mars

    NASA Technical Reports Server (NTRS)

    Fairen, Alberto G.; Dohm, James M.; Baker, Victor R.; dePablo, Miguel A.

    2003-01-01

    Throughout the recorded history of Mars, liquid water has distinctly shaped its landscape, including the prominent circum-Chryse and the northwestern slope valleys outflow channel systems [1], and the extremely flat northern plains topography at the distal reaches of these outflow channel systems.Basing on the ideas of episodic greenhouse atmosphere and water stability on the lowlands of Mars [3], a conceptual scheme for water evolution and associated geomorphologic features on the northern plains can be proposed. This model highlights Tharsis-triggered flood inundations and their direct impact on shaping the northern plains, as well as making possible the existence of fossil and/or extant life.Possible biologic evolution throughout the resulting different climatic and hydrologic conditions would account for very distinct metabolic pathways for hypothesized organisms capable of surviving and perhaps evolving in each aqueous environment, those that existed in the dry and cold periods between the flood inundations, and those organisms that could survive both extremes. Terrestrial microbiota, chemolithotrophic and heterotrophic bacteria, provide exciting analogues for such potential extremophile existence in Mars, especially where long-lived, magmatic-driven hydrothermal activity is indicated [14].

  7. Quantifying subsurface mixing of groundwater from lowland stream perspective.

    NASA Astrophysics Data System (ADS)

    van der Velde, Ype; Torfs, Paul; van der Zee, Sjoerd; Uijlenhoet, Remko

    2013-04-01

    The distribution of time it takes water from the moment of precipitation to reach the catchment outlet is widely used as a characteristic for catchment discharge behaviour, catchment vulnerability to pollution spreading and pollutant loads from catchments to downstream waters. However, this distribution tends to vary in time driven by variability in precipitation and evapotranspiration. Subsurface mixing controls to what extent dynamics in rainfall and evpotranspiration are translated into dynamics of travel time distributions. This insight in hydrologic functioning of catchments requires new definitions and concepts that link dynamics of catchment travel time distributions to the degree of subsurface mixing. In this presentation we propose the concept of STorage Outflow Probability (STOP) functions, that quantify the probability of water parcels stored in a catchment, to leave this catchment by discharge or evapotranspiration. We will show how STOPs relate to the topography and subsurface and how they can be used for deriving time varying travel time distributions of a catchment. The presented analyses will combine a unique dataset of high-frequent discharge and nitrate concentration measurements with results of a spatially distributed groundwater model and conceptual models of water flow and solute transport. Remarkable findings are the large contrasts in discharge behaviour expressed in travel time between lowland and sloping catchments and the strong relationship between evapotranspiration and stream water nutrient concentration dynamics.

  8. Genetic approaches refine ex situ lowland tapir (Tapirus terrestris) conservation.

    PubMed

    Gonçalves da Silva, Anders; Lalonde, Danielle R; Quse, Viviana; Shoemaker, Alan; Russello, Michael A

    2010-01-01

    Ex situ conservation management remains an important tool in the face of continued habitat loss and global environmental change. Here, we use microsatellite marker variation to evaluate conventional assumptions of pedigree-based ex situ population management and directly inform a captive lowland tapir breeding program within a range country. We found relatively high levels of genetic variation (N(total) = 41; mean H(E) = 0.67 across 10 variable loci) and little evidence for relatedness among founder individuals (N(founders) = 10; mean relatedness = -0.05). Seven of 29 putative parent-offspring relationships were excluded by parentage analysis based on allele sharing, and we identified 2 individuals of high genetic value to the population (mk

  9. Quantifying the nutrient flux within a lowland karstic catchment

    NASA Astrophysics Data System (ADS)

    McCormack, T.; Naughton, O.; Johnston, P. M.; Gill, L. W.

    2015-01-01

    Nutrient contamination of surface and groundwaters is an issue of growing importance as the risks associated with agricultural runoff escalate due to increasing demands on global food production. In this study, the nutrient flux occurring within the surface and groundwaters of a lowland karst catchment in western Ireland was investigated with the aid of alkalinity sampling and a hydrological model. Water samples were collected and tested from a variety of rivers, lakes (or turloughs), boreholes and springs at monthly intervals over a three year period. Alkalinity sampling was used to elucidate the contrasting hydrological functioning between different turloughs. Such disparate hydrological functioning was further investigated with the aid of a hydrological model which allowed for an estimate of allogenic and autogenic derived nutrient loading into the karst system. The model also allowed for an investigation of mixing within the turloughs, comparing observed behaviours with the hypothetical conservative behaviour allowed for by the model. Results indicated that at the system outlet to the sea, autogenic recharge had added approximately 35% to the total flow and approximately 85% to the total N-load. Within some turloughs, nutrient loads were found to reduce over the flooded period, even though the turloughs hydrological functioning (and the hydrological model) suggested this should not occur. As such, it was determined that nutrient loss processes were occurring within the system. Denitrification was deemed to be the main process reducing nitrogen concentrations within the turloughs whereas phosphorus loss is thought to occur mostly within the diffuse/epikarst zone.

  10. Quantifying the nutrient flux within a lowland karstic catchment

    NASA Astrophysics Data System (ADS)

    McCormack, T.; Naughton, O.; Johnston, P. M.; Gill, L. W.

    2015-10-01

    Nutrient contamination of surface and groundwaters is an issue of growing importance as the risks associated with agricultural runoff escalate due to increasing demands on global food production. In this study, the nutrient flux occurring within the surface and groundwaters of a lowland karst catchment in western Ireland was investigated with the aid of alkalinity sampling and a hydrological model. Water samples were tested from a variety of rivers, lakes (or turloughs), boreholes and springs at monthly intervals over three years. Alkalinity sampling was used to elucidate the contrasting hydrological functioning between different turloughs. Such disparate hydrological functioning was further investigated with the aid of a hydrological model which allowed for an estimate of allogenic and autogenic derived nutrient loading into the karst system. The model also allowed for an investigation of mixing within the turloughs, comparing observed behaviours with the hypothetical conservative behaviour allowed for by the model. Within the turloughs, nutrient concentrations were found to reduce over the flooded period, even though the turloughs hydrological functioning (and the hydrological model) suggested this should not occur. As such, it was determined that nutrient loss processes were occurring within the system. Denitrification during stable flooded periods (typically 3-4 months per year) was deemed to be the main process reducing nitrogen concentrations within the turloughs whereas phosphorus loss is thought to occur mostly via sedimentation and subsequent soil deposition. The results from this study suggest that, in stable conditions, ephemeral lakes can impart considerable nutrient losses on a karst groundwater system.

  11. Use of buckets as tools by Western lowland gorillas.

    PubMed

    Margulis, Susan W; Steele, Gary R; Kleinfelder, Raymond E

    2012-01-01

    While all great apes have been documented to use tools, gorillas are arguably the least proficient tool users. In 2009, a Western lowland gorilla (Gorilla gorilla gorilla) at the Buffalo Zoo was observed using a bucket, which had been provided as part of normal enrichment, as a tool to collect water. We conducted a brief, ad libitum investigation to confirm the validity of the initial observation. We then carried out a systematic investigation of the behavior in 2010. We collected 72 hr of videotaped data and tested the null hypothesis that the gorillas did not differ in their prevalence of engaging in bucket-use behaviors. We documented that all four adult gorillas in the group used buckets as drinking tools; however, there was significant individual variation in frequency and type of use of buckets. Four of the eight behaviors showed significant variation among individuals. The silverback male and the youngest adult female contacted and held the bucket significantly more than the remaining two adult females. The young female carried and drank from the bucket significantly more than any other individual. Furthermore, she was observed to fill the bucket with water four of the six times during which this behavior was observed. These data provide evidence of the ability of gorillas to utilize tools, given the appropriate environmental conditions. We continue to explore the abilities of gorillas to recognize the functionality of buckets as tools. PMID:22290615

  12. An 8700 year paleoclimate reconstruction from the southern Maya lowlands

    NASA Astrophysics Data System (ADS)

    Wahl, David; Byrne, Roger; Anderson, Lysanna

    2014-11-01

    Analysis of a sediment core from Lago Puerto Arturo, a closed basin lake in northern Peten, Guatemala, has provided an ˜8700 cal year record of climate change and human activity in the southern Maya lowlands. Stable isotope, magnetic susceptibility, and pollen analyses were used to reconstruct environmental change in the region. Results indicate a relatively wet early to middle Holocene followed by a drier late Holocene, which we interpret as reflecting long-term changes in insolation (precession). Higher frequency variability is more likely attributable to changes in ocean/atmosphere circulation in both the North Atlantic and the Pacific Oceans. Pollen and isotope data show that most of the period of prehispanic agricultural settlement, i.e. ˜5000-1000 cal yr BP, was characterized by drier conditions than previous or subsequent periods. The presence of Zea (corn) pollen through peak aridity during the Terminal Classic period (˜1250-1130 cal yr BP) suggests that drought may not have had as negative an impact as previously proposed. A dramatic negative shift in isotope values indicates an increase in precipitation after ˜950 cal yr BP (hereafter BP).

  13. Olfactory discrimination in the western lowland gorilla, Gorilla gorilla gorilla.

    PubMed

    Hepper, Peter G; Wells, Deborah L

    2012-04-01

    The olfactory abilities of great apes have been subject to little empirical investigation, save for a few observational reports. This study, using an habituation/dishabituation task, provides experimental evidence for a core olfactory ability, namely, olfactory discrimination, in the gorilla. In Experiment 1, six zoo-housed western lowland gorillas were individually presented with the same odour on four trials, and with a novel odour on the fifth trial. Odours (almond and vanilla) were presented on plastic balls, and behavioural responses of sniffing and chewing/licking the balls were recorded. A second experiment presented the same odour on four trials and no odour on the fifth to examine whether any dishabituation was due to the presence of a new odour or the absence of the familiar odour. Gorillas habituated their behaviour with repeated presentation of the same odour, but dishabituated, i.e. increased sniffing and chewing/licking, when presented with the novel odour. No dishabituation was noted when using water as the stimulus across all trials or when used as the novel odour. Overall, results show that gorillas are able to discriminate between odours. PMID:22261746

  14. Evapotranspiration from lowland native shrubland ecosystems in Nevada

    NASA Astrophysics Data System (ADS)

    Arnone, J. A.; Jasoni, R. L.; Larsen, J. D.; Fenstermaker, L. F.; Wohlfahrt, G.

    2009-04-01

    Development of new ground water resources in rural lands surrounding urban areas of the arid western United States has been identified as a key to maintaining the economic viability of this region. The extent and rate at which ground water can be sustainably extracted, while avoiding or minimizing environmental impacts, depends to a large degree on how much of the existing resource escapes back to the atmosphere via the process of evapotranspiration (ET). The primary objective of this study was to quantify ET from six lowland basin sites in eastern Nevada and relate ET rates measured at multiple temporal scales to variability in environmental driving forces as well as remotely sensed vegetation structure. It was found that the day-to-day variability in ET was best explained by net radiation and the amount of precipitation of the preceding day. Air temperature, the vapour pressure deficit of air, root-zone soil water content and the remotely-sensed Normalised Difference Vegetation Index (NDVI) were less successful in explaining variability on the daily time scale. On an annual time scale, differences between the six study sites were best explained (r2 = 0.94) by the amount of precipitation - wetter sites featuring higher ET rates. On average ET exceeded precipitation by 84 %, the difference being due to groundwater use. The NDVI explained 65 % of the variability between sites.

  15. An 8700 year paleoclimate reconstruction from the southern Maya lowlands

    USGS Publications Warehouse

    Wahl, David B.; Byrne, Roger; Anderson, Lysanna

    2014-01-01

    Analysis of a sediment core from Lago Puerto Arturo, a closed basin lake in northern Peten, Guatemala, has provided an ∼8700 cal year record of climate change and human activity in the southern Maya lowlands. Stable isotope, magnetic susceptibility, and pollen analyses were used to reconstruct environmental change in the region. Results indicate a relatively wet early to middle Holocene followed by a drier late Holocene, which we interpret as reflecting long-term changes in insolation (precession). Higher frequency variability is more likely attributable to changes in ocean/atmosphere circulation in both the North Atlantic and the Pacific Oceans. Pollen and isotope data show that most of the period of prehispanic agricultural settlement, i.e. ∼5000–1000 cal yr BP, was characterized by drier conditions than previous or subsequent periods. The presence ofZea (corn) pollen through peak aridity during the Terminal Classic period (∼1250–1130 cal yr BP) suggests that drought may not have had as negative an impact as previously proposed. A dramatic negative shift in isotope values indicates an increase in precipitation after ∼950 cal yr BP (hereafter BP).

  16. Hyperspectral Analysis of Rice Phenological Stages in Northeast China

    NASA Astrophysics Data System (ADS)

    Gnyp, M. L.; Yao, Y.; Yu, K.; Huang, S.; Aasen, H.; Lenz-Wiedemann, V. I. S.; Miao, Y.; Bareth, G.

    2012-07-01

    The objective of this contribution is to monitor rice (Oryza sativa L., irrigated lowland rice) growth with multitemporal hyperspectral data during different phenological stages in Northeast China (Sanjiang Plain). Multitemporal hyperspectral data were measured with field spectroradiometers (ASD Inc.: QualitySpec and FieldSpec3) for two field experiments and nine farmers' fields. The field measurements were carried out together with corresponding measurements of agronomic data (aboveground biomass [AGB], Leaf Area Index [LAI], number of tillers). Eight selected standard hyperspectral vegetation indices (VIs), proved in several studies to be highly correlated with AGB or LAI, were calculated on the measured experimental field data. Additionally, the best two-band combinations for the Normalized Ratio Index (NRI) were determined. The results indicate that the NRI performed better than the selected standard VIs at the stages of stem elongation, booting and heading and also across all stages. Especially during the stem elongation stage (R2 = 0.76) and across all stages (R2 = 0.70), the NRI performed best. When applying the NRI on the farmers' field data, the performance was lower (R2 < 0.60). Overall, the sensitive individual wavelengths (±10 nm) for the best two-band combinations were detected at 711 and 799 nm (for tillering stage), 1575 and 1678 nm (for stem elongation stage), 515 and 695 nm (for booting stage), and 533 and 713 nm (for all stages). The results suggest that hyperspectral-based methods can estimate paddy rice AGB with a satisfying accuracy. In the context of precision agriculture, the findings are useful for future development of new hyperspectral devices such as scanners or cameras which could be fixed on tractors or unmanned aerial vehicles (UAVs).

  17. 7 CFR 868.310 - Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled Rice. (See also Â... Milled Rice Principles Governing Application of Standards § 868.310 Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled...

  18. 7 CFR 868.310 - Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled Rice. (See also Â... Milled Rice Principles Governing Application of Standards § 868.310 Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled...

  19. 7 CFR 868.310 - Grades and grade requirements for the classes Long Grain Milled Rice, Medium Grain Milled Rice...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled Rice. (See also Â... classes Long Grain Milled Rice, Medium Grain Milled Rice, Short Grain Milled Rice, and Mixed Milled Rice... (percent) Removed by a 5 plate 3 (percent) Removed by a 6 plate 3 (percent) Through a 6 sieve 3...

  20. Rice Glycosyltransferase (GT) Phylogenomic Database

    DOE Data Explorer

    Ronald, Pamela

    The Ronald Laboratory staff at the University of California-Davis has a primary research focus on the genes of the rice plant. They study the role that genetics plays in the way rice plants respond to their environment. They created the Rice GT Database in order to integrate functional genomic information for putative rice Glycosyltransferases (GTs). This database contains information on nearly 800 putative rice GTs (gene models) identified by sequence similarity searches based on the Carbohydrate Active enZymes (CAZy) database. The Rice GT Database provides a platform to display user-selected functional genomic data on a phylogenetic tree. This includes sequence information, mutant line information, expression data, etc. An interactive chromosomal map shows the position of all rice GTs, and links to rice annotation databases are included. The format is intended to "facilitate the comparison of closely related GTs within different families, as well as perform global comparisons between sets of related families." [From http://ricephylogenomics.ucdavis.edu/cellwalls/gt/genInfo.shtml] See also the primary paper discussing this work: Peijian Cao, Laura E. Bartley, Ki-Hong Jung and Pamela C. Ronalda. Construction of a Rice Glycosyltransferase Phylogenomic Database and Identification of Rice-Diverged Glycosyltransferases. Molecular Plant, 2008, 1(5): 858-877.

  1. Hydrological behavior of a Vertisol under different soil management systems in a rain-fed olive orchard

    NASA Astrophysics Data System (ADS)

    Cabezas, Jose Manuel; Gómez, Jose Alfonso; Auxiliadora Soriano, María

    2016-04-01

    Soil water availability is a major subject in Mediterranean agricultural systems, mainly due to the limited and highly variable annual rainfall, high evaporative demand, and soil hydrological characteristics. The recent expansion of olive cultivation in the rolling-plains of the Guadalquivir valley, due to the higher profitability of new intensive olive orchards, expanded the presence of olive orchards on Vertisols, soils traditionally used for annual rain-fed crops. These soils have a high content of smectitic clays, which give them a high water storage capacity, and are characterized by vertical and deep shrinkage cracks in the dry season, associated to low soil moisture. Farmers make several tillage passes in these olive groves during the summer, in order to cover the cracks and thus reduce soil water loss by evaporation, which will impact especially in rain-fed in the next olive yield. This tillage practice involves removal of plant residues from the soil surface, as well as burying seeds produced by the plants, so this will remain bared at the beginning of the rainy season, when in the Mediterranean climate is frequent occurrence of high-intensity rainfall, which are ideal conditions for soil loss by water erosion, one of the most serious problems for the sustainability of olive cultivation in Andalusia. Although there are some studies showing that water loss by evaporation from deep horizons of a vertic soil might be elevated (eg. Ritchie and Adams, 1974), the presence of plant residues on the soil surface drastically reduced soil water loss (eg Adams et al., 1969). Thus the aim of this study was to assess of soil moisture dynamics in a rain-fed olive orchard growing on a Vertisol under different soil management practices, in Andalusia (southern Spain). Four different soil management treatments were applied, which combined a cover crop (Bromus rubens L.) or bare soil throughout the year by applying herbicides, with tillage in summer to cover the cracks or non

  2. Do NERICA rice cultivars express resistance to Striga hermonthica (Del.) Benth. and Striga asiatica (L.) Kuntze under field conditions?

    PubMed Central

    Rodenburg, Jonne; Cissoko, Mamadou; Kayeke, Juma; Dieng, Ibnou; Khan, Zeyaur R.; Midega, Charles A.O.; Onyuka, Enos A.; Scholes, Julie D.

    2015-01-01

    The parasitic weeds Striga asiatica and Striga hermonthica cause high yield losses in rain-fed upland rice in Africa. Two resistance classes (pre- and post-attachment) and several resistant genotypes have been identified among NERICA (New Rice for Africa) cultivars under laboratory conditions (in vitro) previously. However, little is known about expression of this resistance under field conditions. Here we investigated (1) whether resistance exhibited under controlled conditions would express under representative Striga-infested field conditions, and (2) whether NERICA cultivars would achieve relatively good grain yields under Striga-infested conditions. Twenty-five rice cultivars, including all 18 upland NERICA cultivars, were screened in S. asiatica-infested (in Tanzania) and S. hermonthica-infested (in Kenya) fields during two seasons. Additionally, a selection of cultivars was tested in vitro, in mini-rhizotron systems. For the first time, resistance observed under controlled conditions was confirmed in the field for NERICA-2, -5, -10 and -17 (against S. asiatica) and NERICA-1 to -5, -10, -12, -13 and -17 (against S. hermonthica). Despite high Striga-infestation levels, yields of around 1.8 t ha−1 were obtained with NERICA-1, -9 and -10 (in the S. asiatica-infested field) and around 1.4 t ha−1 with NERICA-3, -4, -8, -12 and -13 (in the S. hermonthica-infested field). In addition, potential levels of tolerance were identified in vitro, in NERICA-1, -17 and -9 (S. asiatica) and in NERICA-1, -17 and -10 (S. hermonthica). These findings are highly relevant to rice agronomists and breeders and molecular geneticists working on Striga resistance. In addition, cultivars combining broad-spectrum resistance with good grain yields in Striga-infested fields can be recommended to rice farmers in Striga-prone areas. PMID:26089591

  3. Satellite Perspectives on Highland - Lowland Human Interaction in Ancient Syria

    NASA Astrophysics Data System (ADS)

    Lönnqvist, M.; Törmä, M.; Lönnqvist, K.; Nuñez, M.

    2012-08-01

    Nowadays we can travel by GoogleEarth 3D to Syria (http://www.worldcountries.info/GoogleEarth/GoogleEarth-Syria.php) and zoom in on the desert landscape of the mountainous region of Jebel Bishri between the Euphrates river and the Syrian Desert. This is the area, where the Finnish archaeological survey and mapping project SYGIS worked in 2000-2010 studying the relationship of humans with their environment from ancient times to the present. What kind of landscape views and visions did the ancients have and how did they utilize them? The present paper focuses on seeking answers for these questions by combining satellite data sources, such as imagery and radar data, with location information of archaeological remains collected on the ground. Landsat as well as QuickBird imagery have been fused with SRTM mission and ASTER DEM data in creating 3D landscape models and fly-over simulations. The oasis of El Kowm on the western piedmont of the mountain seems to have served as a base camp for early huntergatherers and pastoral nomads dwelling seasonally in the region of Jebel Bishri. According to the archaeological finds, the interaction between the lowland and the mountain people already started during the Palaeolithic era but was continued by pastoral nomads of the region from the Neolithic period onwards. The Upper Palaeolithic period meant a clear change in cognitive thinking and obviously in understanding the properties of landscape, visibility and perceiving sceneries in 3D. Mobility of hunter-gatherers and pastoral nomads is based on subsistence economy, but mobility also enhances visions and prospects of phenomena appearing in the horizon.

  4. Wild Western Lowland Gorillas Signal Selectively Using Odor

    PubMed Central

    Klailova, Michelle; Lee, Phyllis C.

    2014-01-01

    Mammals communicate socially through visual, auditory and chemical signals. The chemical sense is the oldest sense and is shared by all organisms including bacteria. Despite mounting evidence for social chemo-signaling in humans, the extent to which it modulates behavior is debated and can benefit from comparative models of closely related hominoids. The use of odor cues in wild ape social communication has been only rarely explored. Apart from one study on wild chimpanzee sniffing, our understanding is limited to anecdotes. We present the first study of wild gorilla chemo-communication and the first analysis of olfactory signaling in relation to arousal levels and odor strength in wild apes. If gorilla scent is used as a signaling mechanism instead of only a sign of arousal or stress, odor emission should be context specific and capable of variation as a function of the relationships between the emitter and perceiver(s). Measured through a human pungency scale, we determined the factors that predicted extreme levels of silverback odor for one wild western lowland gorilla (Gorilla gorilla gorilla) group silverback. Extreme silverback odor was predicted by the presence and intensity of inter-unit interactions, silverback anger, distress and long-calling auditory rates, and the absence of close proximity between the silverback and mother of the youngest infant. Odor strength also varied according to the focal silverback's strategic responses during high intensity inter-unit interactions. Silverbacks appear to use odor as a modifiable form of communication; where odor acts as a highly flexible, context dependent signaling mechanism to group members and extra-group units. The importance of olfaction to ape social communication may be especially pertinent in Central African forests where limited visibility may necessitate increased reliance on other senses. PMID:25006973

  5. Echocardiographic parameters of captive western lowland gorillas (Gorilla gorilla gorilla).

    PubMed

    Murphy, Hayley Weston; Dennis, Patricia; Devlin, William; Meehan, Tom; Kutinsky, Ilana

    2011-12-01

    A total of 163 echocardiographic studies on western lowland gorillas (Gorilla gorilla gorilla) were submitted for evaluation; 140 from 99 animals were suitable for analysis. Of these, 81 studies (42 studies from 35 males ranging in age from 11-41+ yr and 39 studies from 31 females ranging in age from 11-41+ yr) are reported here. Three studies from 3 females and 56 studies from 30 males were excluded from this report due to cardiac abnormalities. Cardiac parameters measured were aortic root (Ao Rt) diameter and left atrial (L atrium) size. Left ventricular (LV) measurements included left ventricular internal diameter in systole (LVID(s)) and diastole (LVID(d)) as well as diastolic septal (IVS) and posterior wall thickness (LVPW). Values considered to be normal in females > 11 yr of age were: Ao Rt < 3.5 cm, L atrium < 4.0 cm, LVID(d) < 5.0 cm, IVS < 1.4 cm, LVPW < 1.4 cm, and ejection fraction (EF) > 60%. The data from male gorillas show a separation in animals based on three cardiac parameters: systolic function, LV cavity size, and LV wall thickness. Male gorillas > 11 yr of age fall into two groups; unaffected and affected. Unaffected animals are defined as those with no echocardiographic abnormalities and a consistent Ao Rt of < 4.0 cm, LVID(d) of < 6.0 cm, IVS and LVPW of <1.5 cm, and an EF of > 58%. The affected group consisted of male gorillas that exhibited changes in echocardiographic parameters representing the presence of cardiovascular disease. The results determined in this database, gathered from data collected from 1999-2009, suggest a sex-based difference between males and females with predominantly males demonstrating evidence of cardiac disease. The most striking finding seen in this study is that of progressive LV hypertrophy and depressed LV EF in affected adult male gorillas. PMID:22204050

  6. Excess growing-season water limits lowland black spruce productivity

    NASA Astrophysics Data System (ADS)

    Dymond, S.; Kolka, R. K.; Bolstad, P. V.; Gill, K.; Curzon, M.; D'Amato, A. W.

    2015-12-01

    The annual growth of many tree species is limited by water availability, with growth increasing as water becomes less scarce. In lowland bogs of northern Minnesota, however, black spruce (Picea mariana) is often exposed to excess water via high water table elevations. These trees grow in thick deposits of organic mucky peat and often have shallow rooting systems to avoid the complete submersion of roots in water. While it is generally believed that black spruce decrease growth rates with rising water table elevations, this hypothesis has not been tested in situ. We used a unique, 50-year record of daily bog water table elevations at the Marcell Experimental Forest (MEF) in northern Minnesota to investigate the relationship between climate and black spruce productivity. Nine 1/20th ha circular plots were established in five different bogs and tree height, diameter-at-breast-height (DBH), and crown class were recorded. Additionally, two perpendicular cores were collected on all trees greater than 10 cm diameter-at-breast-height. Tree cores were sanded, mounted, cross-dated, and de-trended according to standard dendrochronological procedures. Ring width measurements were correlated with precipitation, temperature, and water table elevation using package BootRes in R to determine the climatic variables most associated with stand level productivity. Across the different plots, we found that early growing season water table elevation (May and June) was negatively correlated with both individual and stand-level black spruce growth (p < 0.01), while growth was positively correlated with March temperatures (p < 0.01). No significant relationships existed between black spruce growth and monthly precipitation. If summer water table elevations in these peatland ecosystems rise as is anticipated with more extreme precipitation events due to climate change, we could see an overall decrease in the stand level productivity of black spruce.

  7. Wild western lowland gorillas signal selectively using odor.

    PubMed

    Klailova, Michelle; Lee, Phyllis C

    2014-01-01

    Mammals communicate socially through visual, auditory and chemical signals. The chemical sense is the oldest sense and is shared by all organisms including bacteria. Despite mounting evidence for social chemo-signaling in humans, the extent to which it modulates behavior is debated and can benefit from comparative models of closely related hominoids. The use of odor cues in wild ape social communication has been only rarely explored. Apart from one study on wild chimpanzee sniffing, our understanding is limited to anecdotes. We present the first study of wild gorilla chemo-communication and the first analysis of olfactory signaling in relation to arousal levels and odor strength in wild apes. If gorilla scent is used as a signaling mechanism instead of only a sign of arousal or stress, odor emission should be context specific and capable of variation as a function of the relationships between the emitter and perceiver(s). Measured through a human pungency scale, we determined the factors that predicted extreme levels of silverback odor for one wild western lowland gorilla (Gorilla gorilla gorilla) group silverback. Extreme silverback odor was predicted by the presence and intensity of inter-unit interactions, silverback anger, distress and long-calling auditory rates, and the absence of close proximity between the silverback and mother of the youngest infant. Odor strength also varied according to the focal silverback's strategic responses during high intensity inter-unit interactions. Silverbacks appear to use odor as a modifiable form of communication; where odor acts as a highly flexible, context dependent signaling mechanism to group members and extra-group units. The importance of olfaction to ape social communication may be especially pertinent in Central African forests where limited visibility may necessitate increased reliance on other senses. PMID:25006973

  8. Assessing Weather-Yield Relationships in Rice at Local Scale Using Data Mining Approaches

    PubMed Central

    Delerce, Sylvain; Dorado, Hugo; Grillon, Alexandre; Rebolledo, Maria Camila; Prager, Steven D.; Patiño, Victor Hugo; Garcés Varón, Gabriel; Jiménez, Daniel

    2016-01-01

    Seasonal and inter-annual climate variability have become important issues for farmers, and climate change has been shown to increase them. Simultaneously farmers and agricultural organizations are increasingly collecting observational data about in situ crop performance. Agriculture thus needs new tools to cope with changing environmental conditions and to take advantage of these data. Data mining techniques make it possible to extract embedded knowledge associated with farmer experiences from these large observational datasets in order to identify best practices for adapting to climate variability. We introduce new approaches through a case study on irrigated and rainfed rice in Colombia. Preexisting observational datasets of commercial harvest records were combined with in situ daily weather series. Using Conditional Inference Forest and clustering techniques, we assessed the relationships between climatic factors and crop yield variability at the local scale for specific cultivars and growth stages. The analysis showed clear relationships in the various location-cultivar combinations, with climatic factors explaining 6 to 46% of spatiotemporal variability in yield, and with crop responses to weather being non-linear and cultivar-specific. Climatic factors affected cultivars differently during each stage of development. For instance, one cultivar was affected by high nighttime temperatures in the reproductive stage but responded positively to accumulated solar radiation during the ripening stage. Another was affected by high nighttime temperatures during both the vegetative and reproductive stages. Clustering of the weather patterns corresponding to individual cropping events revealed different groups of weather patterns for irrigated and rainfed systems with contrasting yield levels. Best-suited cultivars were identified for some weather patterns, making weather-site-specific recommendations possible. This study illustrates the potential of data mining for

  9. Assessing Weather-Yield Relationships in Rice at Local Scale Using Data Mining Approaches.

    PubMed

    Delerce, Sylvain; Dorado, Hugo; Grillon, Alexandre; Rebolledo, Maria Camila; Prager, Steven D; Patiño, Victor Hugo; Garcés Varón, Gabriel; Jiménez, Daniel

    2016-01-01

    Seasonal and inter-annual climate variability have become important issues for farmers, and climate change has been shown to increase them. Simultaneously farmers and agricultural organizations are increasingly collecting observational data about in situ crop performance. Agriculture thus needs new tools to cope with changing environmental conditions and to take advantage of these data. Data mining techniques make it possible to extract embedded knowledge associated with farmer experiences from these large observational datasets in order to identify best practices for adapting to climate variability. We introduce new approaches through a case study on irrigated and rainfed rice in Colombia. Preexisting observational datasets of commercial harvest records were combined with in situ daily weather series. Using Conditional Inference Forest and clustering techniques, we assessed the relationships between climatic factors and crop yield variability at the local scale for specific cultivars and growth stages. The analysis showed clear relationships in the various location-cultivar combinations, with climatic factors explaining 6 to 46% of spatiotemporal variability in yield, and with crop responses to weather being non-linear and cultivar-specific. Climatic factors affected cultivars differently during each stage of development. For instance, one cultivar was affected by high nighttime temperatures in the reproductive stage but responded positively to accumulated solar radiation during the ripening stage. Another was affected by high nighttime temperatures during both the vegetative and reproductive stages. Clustering of the weather patterns corresponding to individual cropping events revealed different groups of weather patterns for irrigated and rainfed systems with contrasting yield levels. Best-suited cultivars were identified for some weather patterns, making weather-site-specific recommendations possible. This study illustrates the potential of data mining for

  10. Fingerprint of Seasonal Relative humidity in Rice (Oryza sativa L.): Potential for Paleoclimate Archive

    NASA Astrophysics Data System (ADS)

    Kaushal, R.; Ghosh, P.

    2015-12-01

    Seasonal variability of relative humidity (RH) condition during southwest monsoon (SWM) is strongly related with availability of moisture for rainfall over the continental region. There are ongoing efforts to reconstruct the past monsoonal condition based on geochemical and isotopic records as proxies [1]. However, limited archives have been successfully retrieved for reconstructing moisture condition during SWM [2]. Potential of plants as climate archives and the mechanism involved in transfer of climate signature to the stable isotope composition of oxygen (δ18O) has been demonstarted successfully [3]. Here we are introducing δ18O of rice grain bulk organic matter (δ18OOM) as a new proxy for precise determination of RH during SWM. Rice is a seasonal crop and widely cultivated over the Indian subcontinent during SWM. Here we present δ18OOM of rice grains collected from 15 locations from different climatic zones over the Indian subcontinent, ranging from semi-arid to humid-perhumid. These samples were collected from the harvest of the crop grown at the time of SWM for the period 2012-2014. Each of these climatic zones are characterized by unique range of RH values, which is expected to leave distinct oxygen isotopic signature in the rice grain OM. We compared the δ18OOM values with δ18O of precipitation water, RH and temperature during the period of cultivation. Precipitation δ18O values were obtained from were obtained from OPIC [4]. Our observations document a significant relationship between δ18OOM and RH (R2 =0.62, p<0.001). When the RH level fluctuated from 65% to 88%, δ18OOM tended to vary between 31.5 ‰ to 15.4‰. However, the humid regions with rainfed crop showed significant relationship between δ18OOM and precipitation δ18O. Remaining stations being fed by the both rain and irrigation from river/ groundwater, dampen the rainfall isotope signature in δ18OOM. This approach can be extended in deriving RH of regions of rice cultivation by

  11. Rice: The First Crop Genome.

    PubMed

    Jackson, Scott A

    2016-12-01

    Rice was the first sequenced crop genome, paving the way for the sequencing of additional and more complicated crop genomes. The impact that the genome sequence made on rice genetics and breeding research was immediate, as evidence by citations and DNA marker use. The impact on other crop genomes was evident too, particularly for those within the grass family. As we celebrate 10 years since the completion of the rice genome sequence, we look forward to new empowering tool sets that will further revolutionize research in rice genetics and breeding and result in varieties that will continue to feed a growing population. PMID:27003180

  12. Amended final report on the safety assessment of Oryza Sativa (rice) Bran Oil, Oryza Sativa (rice) Germ Oil, Rice Bran Acid,Oryza Sativa (rice) Bran Wax, Hydrogenated Rice Bran Wax, Oryza Sativa (rice)Bran Extract, Oryza Sativa (rice) Extract, Oryza Sativa (rice) Germ Powder, Oryza Sativa (rice) Starch, Oryza Sativa (rice) Bran, Hydrolyzed Rice Bran Extract, Hydrolyzed Rice Bran Protein, Hydrolyzed Rice Extract, and Hydrolyzed Rice Protein.

    PubMed

    2006-01-01

    This report addresses the safety of cosmetic ingredients derived from rice, Oryza sativa. Oils, Fatty Acids, and Waxes: Rice Bran Oil functions in cosmetics as a conditioning agent--occlusive in 39 formulations across a wide range of product types. Rice Germ Oil is a skin-conditioning agent--occlusive in six formulations in only four product categories. Rice Bran Acid is described as a surfactant-cleansing agent, but was not in current use. Rice Bran Wax is a skin-conditioning agent--occlusive in eight formulations in five product categories. Industry did not directly report any use of Rice Bran Wax. Hydrogenated Rice Bran Wax is a binder, skin-conditioning agent--occlusive, and viscosity-increasing agent--nonaqueous in 11 formulations in six product categories. Rice Bran Oil had an oral LD50 of > 5 g/kg in white rats and Rice Wax had an oral LD50 of > 24 g/kg in male mice. A three-generation oral dosing study reported no toxic or teratologic effects in albino rats fed 10% Rice Bran Oil compared to a control group fed Peanut Oil. Undiluted Rice Bran Oil, Rice Germ Oil, and Hydrogenated Rice Bran Wax were not irritants in animal skin tests. Rice Bran Oil was not a sensitizer. Rice Bran Oil, Rice Germ Oil, Rice Wax, and Hydrogenated Rice Bran Wax were negative in ocular toxicity assays. A mixture of Rice Bran Oil and Rice Germ Oil had a ultraviolet (UV) absorption maximum at 315 nm, but was not phototoxic in a dermal exposure assay. Rice Bran Oil was negative in an Ames assay, and a component, gamma-oryzanol, was negative in bacterial and mammalian mutagenicity assays. Rice oils, fatty acids, and waxes were, at most, mildly irritating in clinical studies. Extracts: Rice Bran Extract is used in six formulations in four product categories. Rice Extract is a hair-conditioning agent, but was not in current use. Hydrolyzed Rice Extract is used in four formulations and current concentration of use data were provided for other uses. Hydrolyzed Rice Bran Extract, described

  13. Sorption, desorption and displacement of ibuprofen, estrone, and 17β estradiol in wastewater irrigated and rainfed agricultural soils.

    PubMed

    Durán-Álvarez, Juan C; Prado, Blanca; Ferroud, Anouck; Juayerk, Narcedalia; Jiménez-Cisneros, Blanca

    2014-03-01

    Sorption and leaching potential of ibuprofen, estrone and 17β estradiol were tested in two agricultural soils: one irrigated using municipal wastewater and the other used in rainfed agriculture. Batch sorption-desorption experiments and undisturbed soil column assays were carried out using both soils to which were added a mixture of the target compounds. The three compounds were sorbed to a different extent by both soils: estrone>17β estradiol>ibuprofen. Higher sorption was observed in the irrigated soil, which was attributed to the accumulation of organic matter caused by wastewater irrigation. Desorption of hormones was hysteretic in the irrigated soil, while ibuprofen showed low hysteresis in both soils. Retardation of the compounds' displacement was consistent with the sorption pattern observed in the batch tests. Retardation factor (RF) was similar for the three compounds in the two tested soils, indicating that the target compounds are much more mobile in the soil columns than would be predicted based on their equilibrium sorption parameters. The results obtained in the experiments clarify the role of wastewater irrigated soils as a filter and degradation media for the target micropollutants. PMID:24370693

  14. Short-term soil loss by eolian erosion in response to different rain-fed agricultural practices

    NASA Astrophysics Data System (ADS)

    Tanner, Smadar; Katra, Itzhak; Zaady, Eli

    2016-04-01

    Eolian (wind) erosion is a widespread process and a major form of soil degradation in arid and semi-arid regions. The present study examined changes in soil properties and eolian soil loss at a field scale in response to different soil treatments in two rain-fed agricultural practices. Field experiments with a boundary-layer wind tunnel and soil analysis were used to obtain the data. Two practices with different soil treatments (after harvest), mechanical tillage and stubble grazing intensities, were applied in the fallow phase of the rotation (dry season). The mechanical tillage and the stubble grazing had an immediate and direct effects on soil aggregation but not on the soil texture, and the contents of soil water, organic matter, and CaCO3. Higher erosion rates, that was measured as fluxes of total eolian sediment and particulate matter <10 μm (PM10), were recorded under mechanical tillage and grazing intensities compared with the undisturbed topsoil of the control plots. The erosion rates were higher in grazing plots than in tillage plots. The calculated soil fluxes in this study indicate potentially rapid soil degradation due to loss of fine particles by wind. The finding may have implications for long-term management of agricultural soils in semi-arid areas.

  15. High temperature combined with drought affect rainfed spring wheat and barley in South-Eastern Russia: I. Phenology and growth

    PubMed Central

    Hossain, Akbar; Teixeira da Silva, Jaime A.; Lozovskaya, Marina Viacheslavovna; Zvolinsky, Vacheslav Petrovich

    2012-01-01

    Heat stress, when combined with drought, is one of the major limitations to food production worldwide, especially in areas that use rainfed agriculture. As the world population continues to grow, and water resources for the crop production decline and temperature increases, so the development of heat- and drought-tolerant cultivars is an issue of global concern. In this context, four barley and two wheat genotypes were evaluated in south-eastern Russia to identify heat- and drought-tolerant genotypes for future breeding programmes by identifying suitable sowing times for specific genotypes. High temperature stress, when combined with drought during late sowing, decreased the days to visible awns, days to heading and days to ripe harvest, finally negatively affecting the growth and development of plants and resulting in a lower plant population m−2, tillers plant−1, plant height and dry matter production m−2. On the other hand, low temperature in combination with early sowing increased the number of days to germination, reduced seedling stand establishment and tillering capacity, finally affecting the growth and development of the crops. Compared to overall performance and optimum sowing date, barley genotypes ‘Zernograd.770’ and ‘Nutans’, and wheat genotype ‘Line4’ performed best in both late (high temperature with drought) and early (low temperature) stress conditions. PMID:23961209

  16. qDTY12.1: a locus with a consistent effect on grain yield under drought in rice

    PubMed Central

    2013-01-01

    Background Selection for grain yield under drought is an efficient criterion for improving the drought tolerance of rice. Recently, some drought-tolerant rice varieties have been developed using this selection criterion and successfully released for cultivation in drought-prone target environments. The process can be made more efficient and rapid through marker-assisted breeding, a well-known fast-track approach in crop improvement. QTLs have been identified for grain yield under drought with large effects against drought-susceptible varieties. Most of the identified QTLs show large QTL × environment or QTL × genetic background interactions. The development of mapping populations in the background of popular high-yielding varieties, screening across environments, including the target environments, and the identification of QTLs with a consistent effect across environments can be a suitable alternative marker-assisted breeding strategy. An IR74371-46-1-1 × Sabitri backcross inbred line population was screened for reproductive-stage drought stress at the International Rice Research Institute, Philippines, and Regional Agricultural Research Station, Nepalgunj, Nepal, in the dry and wet seasons of 2011, respectively. A bulk segregant analysis approach was used to identify markers associated with high grain yield under drought. Results A QTL, qDTY12.1, significantly associated with grain yield under reproductive-stage drought stress was identified on chromosome 12 with a consistent effect in two environments: IRRI, Philippines, and RARS, Nepalgunj, Nepal. This QTL explained phenotypic variance of 23.8% and contributed an additive effect of 45.3% for grain yield under drought. The positive QTL allele for qDTY12.1 was contributed by tolerant parent IR74371-46-1-1. Conclusions In this study, qDTY12.1 showed a consistent effect across environments for high grain yield under lowland reproductive-stage drought stress in the background of popular high

  17. Geographical variation in urinary mercury concentrations among populations living in highland and lowland Bolivia.

    PubMed

    Watanabe, C; Imai, H; Kashiwazaki, H

    1994-05-16

    Mercury (Hg) concentrations were determined in spot urine samples of populations living in the highland and lowland areas of Bolivia. The mean levels of the Hg (U-Hg) were 0.43 and 0.34 micrograms Hg/g creatinine in lowlanders and in highlanders, respectively, which did not suggest existence of high-level exposure to Hg in these populations. In both highlanders and lowlanders, there was a marked difference in levels of U-Hg among different populations. Several lines of evidence suggested that local dietary patterns resulted in the observed difference in U-Hg among different populations. Several lines of evidence suggested that local dietary patterns resulted in the observed difference in U-Hg levels, although the responsible food items could not be specified. In most of the populations examined, females showed higher U-Hg levels than males. Other factors possibly related to the observed geographical differences are discussed. PMID:8023133

  18. Outcrossing Potential between U.S. Blackhull Red Rice and Indica Rice Cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weedy red rice is a major weed pest of rice in the southern U.S. Outcrossing between red rice and commercial tropical japonica rice cultivars has resulted in new weed biotypes that further hinder the effectiveness of weed management. In recent years, indica rice has been used increasingly as a ger...

  19. Maximum outcrossing rate and genetic compatibility between red rice (Oryza sativa) biotypes and Clearfield™ rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although red rice can be selectively controlled with imazethapyr in ClearfieldTM (CL) rice, the transfer of the imazethapyr-resistant gene from CL rice to red rice is an ecological risk. Previous experiments indicated that flowering synchronization and genetic compatibility between cultivated rice a...

  20. Early Holocene lake ecosystem development in the southern Baltic lowlands

    NASA Astrophysics Data System (ADS)

    Słowiński, Michał; Ott, Florian; Kramkowski, Mateusz; Noryśkiewicz, Agnieszka M.; Zawiska, Izabela; Dräger, Nadine; Theuerkauf, Martin; Hass, Christoph; Obremska, Milena; Błaszkiewicz, Mirosław; Kordowski, Jarosław; Tjallingii, Rik; Rzodkiewicz, Monika; Schwab, Markus; Brauer, Achim

    2016-04-01

    The first millennia of the Holocene are characterized by gradual and rapid environmental changes following the warming at the beginning of the Holocene superimposed by short-term climatic instability. Landscape evolution during this period occurred at different time scales due to specific response times of landscape compartments like vegetation succession, soil formation and permafrost thawing. As a consequence, a spatiotemporally heterogeneous pattern of changes occurred particularly in regions close to the margins of the continental ice sheets like the Baltic region. Regional atmospheric circulation patterns were affected by cold catabatic winds from the remains of the Fennoscandian ice sheet. The ongoing deglaciation further influenced the regional climate through meltwater release and related changes in the North Atlantic thermohaline circulation. Both effects declined with the progressive ice sheet melt down. Additionally, the land-sea distribution in the North Sea changed drastically during the final melting phase of the glacial ice sheets. The Baltic Sea development is even more complex due to the strong glacio-isostatic adjustments effects that resulted in open and closed water stages affecting the entire Baltic realm. Consequently, the early Holocene interval of sediment records from the southern Baltic lowlands are not considered as straightforward palaeoclimate archives but need to be interpreted in a broader context. We present five partly varved lake records from northern Poland all including an intriguing highly organic-rich interval interrupting biochemical calcite precipitation at about the same time between 10.5 and 10.2 cal kyr BP. These sediment records have been correlated by independent age models based on varve counting, AMS 14C dating, biostratigraphy and tephrochronology. We present multi-proxy records of early Holocene sediments and our preliminary interpretation suggests hydrological processes as the main reason for the intriguing shifts

  1. Spatial Variability of Streambed Hydraulic Conductivity of a Lowland River

    NASA Astrophysics Data System (ADS)

    Schneidewind, Uwe; Thornton, Steven; Van De Vijver, Ellen; Joris, Ingeborg; Seuntjens, Piet

    2015-04-01

    Streambed hydraulic conductivity K is a key physical parameter, which describes flow processes in the hyporheic zone (HZ), i.e. the dynamic interface between aquifers and streams or rivers. Knowledge of the spatial variability of K is also important for the interpretation of contaminant transport processes in the HZ. Streambed K can vary over several magnitudes at small spatial scales. It depends mostly on streambed sediment characteristics (e.g. effective porosity, grain size, packing), streambed processes (e.g. sedimentation, colmation and erosion) and the development of stream channel geometry and streambed morphology (e.g. dunes, anti-dunes, pool-riffle sequences, etc.). Although heterogeneous in natural streambeds, streambed K is often considered to be a constant parameter due to a lack of information on its spatial distribution. Here we show the spatial variability of streambed K for a small section of the River Tern, a lowland river in the UK. Streambed K was determined for more than 120 vertically and horizontally distributed locations from grain size analyses using four empirical approaches (Hazen, Beyer, Kozeny and the USBR model). Additionally, streambed K was estimated from falling head tests in 36 piezometers installed into the streambed on a 4 m by 16 m grid, by applying the Springer-Gelhar Model. For both methods streambed K followed a log-normal distribution. Variogram analysis was used to deduce the spatial variability of the streambed K values within several streambed profiles parallel and perpendicular to the main flow direction in the stream. Hydraulic conductivity Kg estimated from grain size analyses varied between 1 m/d and 155 m/d with standard deviations of 79% to 99% depending on the empirical approach used. Kh estimated from falling head tests varied between 1 m/d and 22 m/d with a standard deviation of about 50%, depending on the degree of anisotropy assumed. After rescaling the data to obtain a common sample support, Pearson correlation

  2. A long pollen record from lowland Amazonia: Forest and cooling in glacial times

    SciTech Connect

    Colinvaux, P.A.; Moreno, J.E.; Bush, M.B.

    1996-10-04

    A continuous pollen history of more than 40,000 years was obtained from a lake in the lowland Amazon rain forest. Pollen spectra demonstrate that tropical rain forest occupied the region continuously and that savannas or grasslands were not present during the last glacial maximum. The data suggest that the western Amazon forest was not fragmented into refugia in glacial times and that the lowlands were not a source of dust. Glacial age forests were comparable to modern forests but also included species now restricted to higher evaluations by temperature, suggesting a cooling of the order of 5{degrees} to 6{degrees}C. 23 refs., 22 tabs.

  3. Ecology and hydrology of pristine and cutover lowland raised bogs: relationships and implications for restoration

    NASA Astrophysics Data System (ADS)

    Labadz, Jillian; Hart, Roger; Robbins, Jane; Butcher, David; Topliss, David

    2013-04-01

    This paper will examine relationships in vegetation communities and hydrological conditions on areas of lowland raised bog in north west England, comparing damaged and relatively intact sites on two adjacent bogs in Cumbria. Walton Moss is a relatively pristine site whilst and Bolton Fell Moss has a small nature reserve area with remnant vegetation which is surrounded by commercial peat cutting. The intended outcome is to provide a mechanism to inform management decisions, with a view to assisting in the long-term protection and rehabilitation of lowland raised bogs.

  4. Update on organic rice research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic products command a premium in the marketplace and bring greater farmgate value to growers and processors. Although total rice acreage has decreased in Texas over the last ten years, there has been an increase in rice acreage produced under organic management. USDA ARS has conducted research ...

  5. 75 FR 56911 - Request for Public Comment on the United States Standards for Rough Rice, Brown Rice for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-17

    ..., Brown Rice for Processing, and Milled Rice standards were last revised in 1993 (58 FR 68015) and appear... technology used to harvest, process, and test rice; and also rice marketing. To ensure that standards and... learn more about Rough Rice, Brown Rice for Processing, and Milled Rice standardization and...

  6. Rice Root Architectural Plasticity Traits and Genetic Regions for Adaptability to Variable Cultivation and Stress Conditions.

    PubMed

    Sandhu, Nitika; Raman, K Anitha; Torres, Rolando O; Audebert, Alain; Dardou, Audrey; Kumar, Arvind; Henry, Amelia

    2016-08-01

    Future rice (Oryza sativa) crops will likely experience a range of growth conditions, and root architectural plasticity will be an important characteristic to confer adaptability across variable environments. In this study, the relationship between root architectural plasticity and adaptability (i.e. yield stability) was evaluated in two traditional × improved rice populations (Aus 276 × MTU1010 and Kali Aus × MTU1010). Forty contrasting genotypes were grown in direct-seeded upland and transplanted lowland conditions with drought and drought + rewatered stress treatments in lysimeter and field studies and a low-phosphorus stress treatment in a Rhizoscope study. Relationships among root architectural plasticity for root dry weight, root length density, and percentage lateral roots with yield stability were identified. Selected genotypes that showed high yield stability also showed a high degree of root plasticity in response to both drought and low phosphorus. The two populations varied in the soil depth effect on root architectural plasticity traits, none of which resulted in reduced grain yield. Root architectural plasticity traits were related to 13 (Aus 276 population) and 21 (Kali Aus population) genetic loci, which were contributed by both the traditional donor parents and MTU1010. Three genomic loci were identified as hot spots with multiple root architectural plasticity traits in both populations, and one locus for both root architectural plasticity and grain yield was detected. These results suggest an important role of root architectural plasticity across future rice crop conditions and provide a starting point for marker-assisted selection for plasticity. PMID:27342311

  7. Major water-related episodes on the lowlands of Mars

    NASA Astrophysics Data System (ADS)

    Fairén, A. G.; Dohm, J. M.; Baker, V. R.

    2003-04-01

    Throughout the recorded history of Mars, liquid water has distinctly shaped its landscape, including the prominent circum-Chryse and the northwestern slope valleys outflow channel systems (Dohm et al., 2001), and the extremely flat northern plains topography at the distal reaches of these outflow channel systems. Paleotopographic reconstructions of the Tharsis magmatic complex reveal the existence of an Europe-sized Noachian drainage basin and subsequent aquifer system in eastern Tharsis. This basin is proposed to source the magmatic-triggered outburst floods that sculpted the circum-Chryse and NSVs outflow channel systems (Dohm, et al., 2001), entrained boulders, rock, and sediment during passage, and ponded to form sequentially through time various hypothesized oceans, seas, and lakes in the northern plains (Parker et al., 1993; Baker et al., 1991; Scott et al., 1995; Head et al., 1999) and glaciers and rock glaciers and lacustrine environments such as in the southern hemisphere (Baker, 2001). The floodwaters decreased in volume with time due to inadequate groundwater recharge of the Tharsis aquifer system. Basing on the ideas of episodic greenhouse atmosphere and water stability on the lowlands of Mars (Baker et al., 1991), a conceptual scheme for water evolution and associated geomorphologic features on the northern plains can be proposed. This model highlights Tharsis-triggered flood inundations and their direct impact on shaping the northern plains, as well as making possible the existence of fossil and/or extant life. Martian topography, as observed from the Mars Orbiter Laser Altimeter, corresponds well to these ancient flood inundations, including the approximated shorelines that have been proposed for the northern plains (Parker et al., 1993). Stratigraphy, geomorphology, and topography record at least one great Noachian/early Hesperian northern plains ocean (Fairén and De Pablo, 2002), best portrayed by the martian dichotomy boundary or Contact 1, but

  8. Soil moisture changes in two experimental sites in Eastern Spain. Irrigation versus rainfed orchards under organic farming

    NASA Astrophysics Data System (ADS)

    Azorin-Molina, Cesar; Vicente-Serrano, Sergio M.; Cerdà, Artemi

    2013-04-01

    Within the Soil Erosion and Degradation Research Group Experimental Stations, soil moisture is being researched as a key factor of the soil hydrology and soil erosion (Cerdà, 1995; Cerda, 1997; Cerdà 1998). This because under semiarid conditions soil moisture content plays a crucial role for agriculture, forest, groundwater recharge and soil chemistry and scientific improvement is of great interest in agriculture, hydrology and soil sciences. Soil moisture has been seeing as the key factor for plant photosynthesis, respiration and transpiration in orchards (Schneider and Childers, 1941) and plant growth (Veihmeyer and Hendrickson, 1950). Moreover, soil moisture determine the root growth and distribution (Levin et al., 1979) and the soil respiration ( Velerie and Orchard, 1983). Water content is expressed as a ratio, ranging from 0 (dry) to the value of soil porosity at saturation (wet). In this study we present 1-year of soil moisture measurements at two experimental sites in the Valencia region, Eastern Spain: one representing rainfed orchard typical from the Mediterranean mountains (El Teularet-Sierra de Enguera), and a second site corresponding to an irrigated orange crop (Alcoleja). The EC-5 soil moisture smart sensor S-SMC-M005 integrated with the field-proven ECH2O™ Sensor and a 12-bit A/D has been choosen for measuring soil water content providing ±3% accuracy in typical soil conditions. Soil moisture measurements were carried out at 5-minute intervals from January till December 2012. In addition, soil moisture was measured at two depths in each landscape: 2 and 20 cm depth - in order to retrieve a representative vertical cross-section of soil moisture. Readings are provided directly from 0 (dry) to 0.450 m3/m3 (wet) volumetric water content. The soil moisture smart sensor is conected to a HOBO U30 Station - GSM-TCP which also stored 5-minute temperature, relative humidity, dew point, global solar radiation, precipitation, wind speed and wind direction

  9. Impact of climate change on water balance components in Mediterranean rainfed olive orchards under tillage or cover crop soil management

    NASA Astrophysics Data System (ADS)

    Rodríguez-Carretero, María Teresa; Lorite, Ignacio J.; Ruiz-Ramos, Margarita; Dosio, Alessandro; Gómez, José A.

    2013-04-01

    The rainfed olive orchards in Southern Spain constitute the main socioeconomic system of the Mediterranean Spanish agriculture. These systems have an elevated level of complexity and require the accurate characterization of crop, climate and soil components for a correct management. It is common the inclusion of cover crops (usually winter cereals or natural cover) intercalated between the olive rows in order to reduce water erosion. Saving limited available water requires specific management, mowing or killing these cover crops in early spring. Thus, under the semi-arid conditions in Southern Spain the management of the cover crops in rainfed olive orchards is essential to avoid a severe impact to the olive orchards yield through depletion of soil water. In order to characterize this agricultural system, a complete water balance model has been developed, calibrated and validated for the semi-arid conditions of Southern Spain, called WABOL (Abazi et al., 2013). In this complex and fragile system, the climate change constitutes a huge threat for its sustainability, currently limited by the availability of water resources, and its forecasted reduction for Mediterranean environments in Southern Spain. The objective of this study was to simulate the impact of climate change on the different components of the water balance in these representative double cropping systems: transpiration of the olive orchard and cover crop, runoff, deep percolation and soil water content. Four climatic scenarios from the FP6 European Project ENSEMBLES were first bias corrected for temperatures and precipitation (Dosio and Paruolo, 2011; Dosio et al., 2012) and, subsequently, used as inputs for the WABOL model for five olive orchard fields located in Southern Spain under different conditions of crop, climate, soils and management, in order to consider as much as possible of the variability detected in the Spanish olive orchards. The first results indicate the significant effect of the cover

  10. Awns reduce grain number to increase grain size and harvestable yield in irrigated and rainfed spring wheat

    PubMed Central

    Rebetzke, G. J.; Bonnett, D. G.; Reynolds, M. P.

    2016-01-01

    Genotypic variation in ear morphology is linked to differences in photosynthetic potential to influence grain yield in winter cereals. Awns contribute to photosynthesis, particularly under water-limited conditions when canopy assimilation is restricted. We assessed performance of up to 45 backcross-derived, awned–awnletted NILs representing four diverse genetic backgrounds in 25 irrigated or rainfed, and droughted environments in Australia and Mexico. Mean environment grain yields were wide-ranging (1.38–7.93 t ha−1) with vegetative and maturity biomass, plant height, anthesis date, spike number, and harvest index all similar (P >0.05) for awned and awnletted NILs. Overall, grain yields of awned–awnletted sister-NILs were equivalent, irrespective of yield potential and genetic background. Awnletted wheats produced significantly more grains per unit area (+4%) and per spike (+5%) reflecting more fertile spikelets and grains in tertiary florets. Increases in grain number were compensated for by significant reductions in grain size (–5%) and increased frequency (+0.8%) of small, shrivelled grains (‘screenings’) to reduce seed-lot quality of awnletted NILs. Post-anthesis canopies of awnletted NILs were marginally warmer over all environments (+0.27 °C) but were not different and were sometimes cooler than awned NILs at cooler air temperatures. Awns develop early and represented up to 40% of total spikelet biomass prior to ear emergence. We hypothesize that the allocation of assimilate to large and rapidly developing awns decreases spikelet number and floret fertility to reduce grain number, particularly in distal florets. Individual grain size is increased to reduce screenings and to increase test weight and milling quality, particularly in droughted environments. Despite the average reduction in grain size, awnless lines could be identified that combined higher grain yield with larger grain size, increased grain protein concentration, and reduced

  11. Effects of conservation tillage practices on ammonia emissions from Loess Plateau rain-fed winter wheat fields

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Zhou, Chunju; Li, Na; Han, Kun; Meng, Yuan; Tian, Xiaoxiao; Wang, Linquan

    2015-03-01

    Ammonia emissions from agricultural activities contribute to air pollution. For the rain-fed winter wheat system in the Loess Plateau there is a lack of information about ammonia emissions. Current study aimed to provide field data on ammonia emissions affected by conservation tillage practices and nitrogen applications. A two-year field experiment was conducted during 2011-2013 wheat growing seasons followed a split-plot design. Main plots consisted of one conventional tillage (CT, as the control) and five conservation tillage systems, i.e., stalk mulching (SM), film mulching (FM), ridge tillage (RT), ridge tillage with film mulch on the ridge (RTfm), and ridge tillage with film mulch on the ridge and stalk mulch in the furrow (RTfmsm); while subplots consisted of two nitrogen application rates, i.e., 0 and 180 kg N ha-1. Ammonia emissions were measured using an acid trapping method with vented chambers. Results showed ammonia fluxes peaked during the first 10 days after fertilization. On average, nitrogen application increased ammonia emissions by 26.5% (1.31 kg N ha-1) compared with treatments without nitrogen application (P < 0.05). Ammonia fluxes were strongly dependent on soil ammonium, moisture, and temperature. Tillage systems had significant effects on ammonia emissions. On average, conservation tillage practices reduced ammonia emissions by 7.7% (0.46 kg N ha-1) compared with conventional tillage (P < 0.05), with FM most effective. Deep-band application of nitrogen fertilizer, stalk mulches, and film mulches were responsible for reductions in ammonia emissions from nitrogen fertilization in conservation tillage systems, thus they were recommended to reduce ammonia emissions from winter wheat production regions in the southern Loess Plateau.

  12. Awns reduce grain number to increase grain size and harvestable yield in irrigated and rainfed spring wheat.

    PubMed

    Rebetzke, G J; Bonnett, D G; Reynolds, M P

    2016-04-01

    Genotypic variation in ear morphology is linked to differences in photosynthetic potential to influence grain yield in winter cereals. Awns contribute to photosynthesis, particularly under water-limited conditions when canopy assimilation is restricted. We assessed performance of up to 45 backcross-derived, awned-awnletted NILs representing four diverse genetic backgrounds in 25 irrigated or rainfed, and droughted environments in Australia and Mexico. Mean environment grain yields were wide-ranging (1.38-7.93 t ha(-1)) with vegetative and maturity biomass, plant height, anthesis date, spike number, and harvest index all similar (P >0.05) for awned and awnletted NILs. Overall, grain yields of awned-awnletted sister-NILs were equivalent, irrespective of yield potential and genetic background. Awnletted wheats produced significantly more grains per unit area (+4%) and per spike (+5%) reflecting more fertile spikelets and grains in tertiary florets. Increases in grain number were compensated for by significant reductions in grain size (-5%) and increased frequency (+0.8%) of small, shrivelled grains ('screenings') to reduce seed-lot quality of awnletted NILs. Post-anthesis canopies of awnletted NILs were marginally warmer over all environments (+0.27 °C) but were not different and were sometimes cooler than awned NILs at cooler air temperatures. Awns develop early and represented up to 40% of total spikelet biomass prior to ear emergence. We hypothesize that the allocation of assimilate to large and rapidly developing awns decreases spikelet number and floret fertility to reduce grain number, particularly in distal florets. Individual grain size is increased to reduce screenings and to increase test weight and milling quality, particularly in droughted environments. Despite the average reduction in grain size, awnless lines could be identified that combined higher grain yield with larger grain size, increased grain protein concentration, and reduced screenings. PMID

  13. [Effects of different film mulch and ridge-furrow cropping patterns on yield formation and water translocation of rainfed potato].

    PubMed

    Qin, Shu-Hao; Zhang, Jun-Lian; Wang, Di; Pu, Yu-Lin; Du, Quan-Zhong

    2011-02-01

    This paper studied the effects of different film mulch and ridge-furrow cropping patterns on the yield formation and water translocation of rainfed potato in the semi-arid area of west Loess Plateau. Comparing with those under traditional harrowed bedding without film mulch (T1), the potato yield under harrowed bedding with film mulching (T2), completely mulched alternating narrow and wide ridges with furrow planting (T3), completely mulched alternating narrow and wide ridges with ridge planting (T4), mulched raised bedding with furrow planting (T5), and mulched raised bedding with bedding planting (T6) was increased by 50.1%, 75.9%, 86.8%, 69.6%, and 60. 6%, and the water use efficiency (WUE) was increased by 47.0%, 82.7%, 84.0%, 75.2%, and 54.3% respectively, with the increments being the highest under T4 and T3. All the film much and ridge-furrow cropping patterns improved the yield component of potato, and T4 and T3 were most beneficial to the increase of mid and big tubers, tuber number per plant, and tuber yield per plant, and to the decrease of the proportions of green and blet tubers. It was concluded that completely mulched alternating narrow and wide ridges with ridge planting (T4) and completely mulched alternating narrow and wide ridges with furrow planting (T3) were the two better cropping patterns in water-saving and high yielding for potato cultivation in semiarid areas. PMID:21608252

  14. Plant available silicon in South-east Asian rice paddy soils - relevance of agricultural practice and of abiotic factors

    NASA Astrophysics Data System (ADS)

    Marxen, A.; Klotzbücher, T.; Vetterlein, D.; Jahn, R.

    2012-12-01

    Background Silicon (Si) plays a crucial role in rice production. Si content of rice plants exceeds the content of other major nutrients such as nitrogen, phosphorous or potassium. Recent studies showed that in some environments external supply of Si can enhance the growth of rice plants. Rice plants express specific Si transporters to absorb Si from soil solutions in form of silicic acid, which precipitates in tissue cells forming amorphous silica bodies, called phytoliths. The phytoliths are returned to soils with plant residues. They might be a main source of plant available silicic acid in soils. Aims In this study we assess the effects of rice paddy cultivation on the stocks of `reactive` Si fractions in mineral topsoils of rice paddy fields in contrasting landscapes. The `reactive` Si fractions are presumed to determine the release of plant-available silicic acid in soils. We consider the relevance of abiotic factors (mineral assemblage; soil weathering status) and agricultural practice for these fractions. Agricultural practices, which were assumed to affect the stocks of `reactive` Si were (i) the usage of different rice varieties (which might differ in Si demand), (ii) straw residue management (i.e., whether straw residues are returned to the fields or removed and used e.g. as fodder), and (iii) yield level and number of crops per year. Material and methods Soils (top horizon of about 0-20 cm depth) were sampled from rice paddy fields in 2 mountainous and 5 lowland landscapes of contrasting geologic conditions in Vietnam and the Philippines. Ten paddy fields were sampled per landscape. The rice paddy management within landscapes differed when different farmers and/or communities managed the fields. We analysed the following fractions of `reactive` Si in the soils: acetate-extractable Si (dissolved and easily exchangeable Si), phosphate-extractable Si (adsorbed Si), oxalate extractable Si (Si associated with poorly-ordered sesquioxides), NaOH extractable Si

  15. Gene flow from herbicide-resistant and non-resistant rice into red rice populations in U.S. rice fields: A survey of current evidence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diverse red rice types infest U.S. rice fields. These infestations have remained widespread despite recent successes in controlling red rice in newly-introduced herbicide-resistant rice systems. As a result, the distribution and genetic background of red rice, and the degree to which red rice inte...

  16. The Land Remembers: Landscape Terms and Place Names in Lowland Chontal of Oaxaca, Mexico

    ERIC Educational Resources Information Center

    O'Connor, Loretta; Kroefges, Peter C.

    2008-01-01

    This paper examines landscape terminology and place names of the Chontal region in the state of Oaxaca in southern Mexico, with a focus on terms from Lowland Chontal, a highly endangered language spoken near the Pacific coast. In addition to the linguistic analysis, the paper presents a general description of the physical geography of the area and…

  17. Instream wood as a driver of nutrient attenuation in a lowland sandy stream

    NASA Astrophysics Data System (ADS)

    Klaar, Megan; Shelley, Felicity; Blaen, Phil; Dapelo, Davide; Trimmer, Mark; Bridgeman, John; Hannah, David; Krause, Stefan

    2016-04-01

    Our poster outlines our research to assess the potential of instream wood to enhance nutrient (nitrogen and carbon) attenuating potential in UK lowland rivers. Using cutting-edge distributed temperature sensing, geophysical technologies, novel microbial metabolic activity tracers and 15N isotope tracer applications, we are able to identify how instream wood alters hyporheic exchange fluxes and residence times which control the development and occurrence of biogeochemical hotspots, which facilitate nitrogen removal. Initial results show that instream wood increases surface water downwelling into the hyporheic, creating increased hyporheic mixing. Metabolic tracer, nutrient and modelling data reveal a correlation between these hyporheic exchange flow locations and increased denitrification hotspots. This data in conjunction with ongoing experimentation suggests that instream wood could be used in river basin management and river restoration efforts to improve water quality and hydromorphic integrity within lowland sandy streams. Ongoing work seeks to quantify the efficiency of alternative (stationary and transient) wood designs for controlled alteration and management of hyporheic exchange fluxes and residence times and nutrient turnover in the streambed. Outputs from this project will provide a quantitative understanding of the optimal design and efficiency of instream wood structures for removing excess nitrate from streambed sediments of nutrient impacted lowland rivers. This information will directly impact UK and European river restoration policies and inform decisions of whether wood restoration in UK lowland rivers should be promoted on a national level and how the most efficient strategies should be designed.

  18. Phylogeography of Declining Relict and Lowland Leopard Frogs in the Desert Southwest of North America

    EPA Science Inventory

    We investigated the phylogeography of the closely related relict leopard frog (Rana onca) and lowland leopard frog (R. yavapaiensis) – two declining anurans from the warm-desert regions of southwestern North America. We used sequence data from two mitochondrial DNA genes to asses...

  19. Tephra layers as correlation tools of neogene coal-bearing strata from the Kenai lowland, Alaska

    SciTech Connect

    Reinink-Smith, L.M.

    1995-03-01

    Thirty-two tephra layers, exposed in coal beds of the Miocene and Pliocene Beluga and Sterling Formations along the shores of the Kenai lowland on the northwestern Kenai Peninsula, Alaska, were studied in detail to improve the geochronology and regional correlation of the Sterling Formation and test prior correlations that were based on palynology and physical tracing of beds over short distances. Published radiogenic isotope data suggest an age span of approximately 4 m.y. for the Sterling Formation at this location but give discordant ages for individual samples depending on dating techniques. A crystal-rich tephra layer near the middle of the section was traced across the Kenai lowland as one or two ash falls based on stratigraphic position, inertinite contents of adjacent coal, geochemical and mineralogical analyses, and individual characteristics. A pumice-rich layer deposited near the top of the Sterling Formation is preserved at two localities on the northwestern and southeastern sides of the Kenai lowland. Geochemical similarities, similar glass morphologies, and an absence of opaque phases characterize this layer as a single ash fall and allow correlation. On a regional scale, these correlations concur with previous correlations and show that a shallow anticline with a northwest-southeast-trending axis extends across the Kenai lowland. 28 refs., 14 figs., 1 tab.

  20. BIOGENIC VOLATILE ORGANIC COMPOUND EMISSIONS FROM A LOWLAND TROPICAL WET FOREST IN COSTA RICA

    EPA Science Inventory

    Twenty common plant species were screened for emissions of biogenic volatile organic compounds (BVOCS) at a lowland tropical wet forest site in Costa Rica. Ten of the species. examined emitted substantial quantities of isoprene. These species accounted for 35-50% of the total bas...

  1. Alien Roadside Species More Easily Invade Alpine than Lowland Plant Communities in a Subarctic Mountain Ecosystem

    PubMed Central

    Lembrechts, Jonas J.; Milbau, Ann; Nijs, Ivan

    2014-01-01

    Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including the plant strategies that are most affected, along three elevational gradients in a subarctic mountain ecosystem. We also examine whether mountain roads promote the introduction and invasion of alien plant species from the lowlands to the alpine zone. Observations of plant community composition were made together with abiotic, biotic and anthropogenic factors in 60 T-shaped transects. Alpine plant communities reacted differently to road disturbances than their lowland counterparts. On high elevations, the roadside species composition was more similar to that of the local natural communities. Less competitive and ruderal species were present at high compared with lower elevation roadsides. While the effects of roads thus seem to be mitigated in the alpine environment for plant species in general, mountain plant communities are more invasible than lowland communities. More precisely, relatively more alien species present in the roadside were found to invade into the surrounding natural community at high compared to low elevations. We conclude that effects of roads and introduction of alien species in lowlands cannot simply be extrapolated to the alpine and subarctic environment. PMID:24586947

  2. An analysis of modern pollen rain from the Maya lowlands of northern Belize

    USGS Publications Warehouse

    Bhattacharya, T.; Beach, T.; Wahl, D.

    2011-01-01

    In the lowland Maya area, pollen records provide important insights into the impact of past human populations and climate change on tropical ecosystems. Despite a long history of regional paleoecological research, few studies have characterized the palynological signatures of lowland ecosystems, a fact which lowers confidence in ecological inferences made from palynological data. We sought to verify whether we could use pollen spectra to reliably distinguish modern ecosystem types in the Maya lowlands of Central America. We collected 23 soil and sediment samples from eight ecosystem types, including upland, riparian, secondary, and swamp (bajo) forests; pine savanna; and three distinct wetland communities. We analyzed pollen spectra with non-metric multidimensional scaling (NMDS), and found significant compositional differences in ecosystem types' pollen spectra. Forested sites had spectra dominated by Moraceae/Urticaceae pollen, while non-forested sites had significant portions of Poaceae, Asteraceae, and Amaranthaceae pollen. Upland, bajo, and riparian forest differed in representation of Cyperaceae, Bactris-type, and Combretaceae/Melastomataceae pollen. High percentages of pine (Pinus), oak (Quercus), and the presence of Byrsonima characterized pine savanna. Despite its limited sample size, this study provides one of the first statistical analyses of modern pollen rain in the Maya lowlands. Our results show that pollen assemblages can accurately reflect differences between ecosystem types, which may help refine interpretations of pollen records from the Maya area. ?? 2010 Elsevier B.V.

  3. Bird communities associated with succession and management of lowland conifer forests

    USGS Publications Warehouse

    Dawson, D.K.

    1979-01-01

    Data from published bird censuses were used to determine changes in avian communities in relation to plant succession, fire, type conversion, and timber management practices in lowland conifer forests in the northeastern United States. With modifications in current logging practices, habitat for the bird species that nest in undisturbed stands can be provided. Management guidelines are recommended.

  4. Geologic framework of the Willamette Lowland aquifer system, Oregon and Washington

    USGS Publications Warehouse

    Gannett, Marshall W.; Caldwell, Rodney R.

    1998-01-01

    This report describes the Cenozoic geology of the Willamette Lowland physiographic province, and the geologic framework of the regional ground-water flow system. Five regional hydrogeologic units are identified and described. The report includes maps showing the altitude of the top and the thickness of each hydrogeologic unit.

  5. Suspected macular degeneration in a captive Western lowland gorilla (Gorilla gorilla gorilla).

    PubMed

    Steinmetz, Andrea; Bernhard, Andreas; Sahr, Sabine; Oechtering, Gerhard

    2012-09-01

    The case of a 31-year-old captive female Western lowland gorilla (Gorilla gorilla gorilla) with decreased near vision but good distance vision is presented. Examination of the fundus revealed drusen-like bodies in the macula presumably because of an age-related macular degeneration (AMD). PMID:22702721

  6. Draft Genome Sequence of Lactobacillus gorillae Strain KZ01T, Isolated from a Western Lowland Gorilla

    PubMed Central

    Tsuchida, Sayaka; Nezuo, Maiko; Tsukahara, Masatoshi; Ogura, Yoshitoshi; Hayashi, Tetsuya

    2015-01-01

    Here, we report the draft genome sequence of Lactobacillus gorillae strain KZ01T isolated from a western lowland gorilla (Gorilla gorilla gorilla). This genome sequence will be helpful for the comparative genomics between human and nonhuman primate-associated Lactobacillus. PMID:26472838

  7. Late Quaternary lake records from the Anadyr Lowland, Central Chukotka (Russia)

    NASA Astrophysics Data System (ADS)

    Lozhkin, Anatoly; Anderson, Patricia

    2013-05-01

    Three lake cores provide insight into the vegetation and climate history of the past ∼45,000 14C yr in the Anadyr Lowland, a key paleogeographic link between the Bering Land Bridge (BLB) and interior Western Beringia (WB). Although not without chronological issues, these records suggest that the Late Pleistocene interstade (approximating Oxygen Isotope Stage (OIS) 3) was a time of unstable environments consistent with previous interpretations for southern areas of WB and in contrast to more stable conditions inferred for northern WB. A hiatus in the records during OIS2 implies dry, frigid environments in the Anadyr Lowland. Previous research suggested that Chuktoka was a westward extension of relatively mesic environments of the BLB, which acted as a “filter” to intercontinental migrations. The Lowland data indicate that Chukotka may have been more of a transitional zone between mesic BLB and more xeric regions of western WB. A structurally novel biome dominated by deciduous forest and high-shrub tundra was proposed as occupying much of Beringia between ∼11,000 and 9000 14C yr BP. The unusual pollen assemblage that characterizes the Lowland suggests that perhaps a second biome was also present in Beringia, one that was dominated by meadows with Betula shrub thickets.

  8. Draft Genome Sequence of Lactobacillus gorillae Strain KZ01T, Isolated from a Western Lowland Gorilla.

    PubMed

    Tsuchida, Sayaka; Nezuo, Maiko; Tsukahara, Masatoshi; Ogura, Yoshitoshi; Hayashi, Tetsuya; Ushida, Kazunari

    2015-01-01

    Here, we report the draft genome sequence of Lactobacillus gorillae strain KZ01(T) isolated from a western lowland gorilla (Gorilla gorilla gorilla). This genome sequence will be helpful for the comparative genomics between human and nonhuman primate-associated Lactobacillus. PMID:26472838

  9. Widespread loess-like deposit in the Martian northern lowlands identifies Middle Amazonian climate change

    USGS Publications Warehouse

    Skinner, James A.; Tanaka, Kenneth L.; Thomas Platz

    2014-01-01

    Consistently mappable units critical to distinguishing the style and interplay of geologic processes through time are sparse in the Martian lowlands. This study identifies a previously unmapped Middle Amazonian (ca. 1 Ga) unit (Middle Amazonian lowland unit, mAl) that postdates the Late Hesperian and Early Amazonian lowland plains by >2 b.y. The unit is regionally defined by subtle marginal scarps and slopes, has a mean thickness of 32 m, and extends >3.1 × 106 km2 between lat 35°N and 80°N. Pedestal-type craterforms and nested, arcuate ridges (thumbprint terrain) tend to occur adjacent to unit mAl outcrops, suggesting that current outcrops are vestiges of a more extensive deposit that previously covered ∼16 × 106 km2. Exposed layers, surface pits, and the draping of subjacent landforms allude to a sedimentary origin, perhaps as a loess-like deposit emplaced rhythmically through atmospheric fallout. We propose that unit mAl accumulated coevally with, and at the expense of, the erosion of the north polar basal units, identifying a major episode of Middle Amazonian climate-driven sedimentation in the lowlands. This work links ancient sedimentary processes to climate change that occurred well before those implied by current orbital and spin axis models.

  10. Earth observing data and methods for advancing water harvesting technologies in the semi-arid rain-fed environments of India

    USGS Publications Warehouse

    Sharma, C.; Thenkabail, P.; Sharma, R. R.

    2011-01-01

    The paper develops approaches and methods of modeling and mapping land and water productivity of rain-fed crops in semi-arid environments of India using hyperspectral, hyperspatial, and advanced multispectral remote sensing data and linking the same to field-plot data and climate station data. The overarching goal is to provide information to advance water harvesting technologies in the agricultural croplands of the semi-arid environments of India by conducting research in a representative pilot site in Jodhpur, Rajasthan, India. ?? 2011 IEEE.

  11. Lowland tapir (Tapirus terrestris) distribution, activity patterns and relative abundance in the Greater Madidi-Tambopata Landscape.

    PubMed

    Wallace, Robert; Ayala, Guido; Viscarra, Maria

    2012-12-01

    Lowland tapir distribution is described in northwestern Bolivia and southeastern Peru within the Greater Madidi-Tambopata Landscape, a priority Tapir Conservation Unit, using 1255 distribution points derived from camera trapping efforts, field research and interviews with park guards from 5 national protected areas and hunters from 19 local communities. A total of 392 independent camera trapping events from 14 camera trap surveys at 11 sites demonstrated the nocturnal and crepuscular activity patterns (86%) of the lowland tapir and provide 3 indices of relative abundance for spatial and temporal comparison. Capture rates for lowland tapirs were not significantly different between camera trapping stations placed on river beaches versus those placed in the forest. Lowland tapir capture rates were significantly higher in the national protected areas of the region versus indigenous territories and unprotected portions of the landscape. Capture rates through time suggested that lowland tapir populations are recovering within the Tuichi Valley, an area currently dedicated towards ecotourism activities, following the creation (1995) and subsequent implementation (1997) of the Madidi National Park in Bolivia. Based on our distributional data and published conservative estimates of population density, we calculated that this transboundary landscape holds an overall lowland tapir population of between 14 540 and 36 351 individuals, of which at least 24.3% are under protection from national and municipal parks. As such, the Greater Madidi-Tambopata Landscape should be considered a lowland tapir population stronghold and priority conservation efforts are discussed in order to maintain this population. PMID:23253372

  12. Accuracy of satellite rainfall estimates in the Blue Nile Basin: Lowland plain versus highland mountain

    NASA Astrophysics Data System (ADS)

    Gebremichael, Mekonnen; Bitew, Menberu M.; Hirpa, Feyera A.; Tesfay, Gebrehiwot N.

    2014-11-01

    The demand for accurate satellite rainfall products is increasing particularly in Africa where ground-based data are mostly unavailable, timely inaccessible, and unreliable. In this study, the accuracy of three widely used, near-global, high-resolution satellite rainfall products (CMORPH, TMPA-RT v7, TMPA-RP v7), with a spatial resolution of 0.25° and a temporal resolution of 3 h, is assessed over the Blue Nile River Basin, a basin characterized by complex terrain and tropical monsoon. The assessment is made using relatively dense experimental networks of rain gauges deployed at two, 0.25° × 0.25°, sites that represent contrasting topographic features: lowland plain (mean elevation of 719 m.a.s.l.) and highland mountain (mean elevation of 2268 m.a.s.l.). The investigation period covers the summer seasons of 2012 and 2013. Compared to the highland mountain site, the lowland plain site exhibits marked extremes of rain intensity, higher mean rain intensity when it rains, lower frequency of rain occurrence, and smaller seasonal rainfall accumulation. All the satellite products considered tend to overestimate the mean rainfall rate at the lowland plain site, but underestimate it at the highland mountain site. The satellite products miss more rainfall at the highland mountain site than at the lowland plain site, and underestimate the heavy rain rates at both sites. Both sites have uncertainty (root mean square error) values greater than 100% for 3 h accumulations of <5 mm, or daily accumulations of <10 mm, and the uncertainty values decrease with increasing rainfall accumulation. Among the satellite products, CMORPH suffers from a large positive bias at the lowland plain site, and TMPA-RP and TMPA-RT miss a large number of rainfall events that contribute nearly half of the total rainfall at the highland mountain.

  13. Circadian and ultradian extrasystole rhythms in healthy individuals at elevated versus lowland altitudes

    NASA Astrophysics Data System (ADS)

    Kujanik, Stefan; Mikulecky, Miroslav

    2010-09-01

    We defined chronobiologic norms for supraventricular and ventricular single extrasystoles (SV and VE, respectively) in healthy older males in lowland areas. The study was extended to higher altitudes, where hypobaric hypoxia was expected to increase extrasystole frequency, while perhaps not changing rhythmicity. In healthy men (lowland n = 37, altitude n = 22), aged 49-72 years, mean numbers of SVs and VEs were counted over a 24-h period. Cosinor regression was used to test the 24-h rhythm and its 2nd-10th harmonics. The resulting approximating function for either extrasystole type includes its point, 95% confidence interval of the mean, and 95% tolerance for single measurement estimates. Separate hourly differences (delta) between altitude and lowland ( n = 59) were also analysed. Hourly means were significantly higher in the mountains versus lowland, by +0.8 beats/h on average for SVs, and by +0.9 beats/h for VEs. A relatively rich chronogram for VEs in mountains versus lowland exists. Delta VEs clearly display a 24-h component and its 2nd, 3rd, 4th and 7th harmonics. This results in significantly higher accumulation of VEs around 8.00 a.m., 11.00 a.m. and 3.00 p.m. in the mountains. The increase in extrasystole occurrence in the mountains is probably caused by higher hypobaric hypoxia and resulting sympathetic drive. Healthy men at elevated altitudes show circadian and several ultradian rhythms of single VEs dependent on the hypoxia level. This new methodological approach—evaluating the differences between two locations using delta values—promises to provide deeper insight into the occurrence of premature beats.

  14. Functional trait composition of aquatic plants can serve to disentangle multiple interacting stressors in lowland streams.

    PubMed

    Baattrup-Pedersen, Annette; Göthe, Emma; Riis, Tenna; O'Hare, Matthew T

    2016-02-01

    Historically, close attention has been paid to negative impacts associated with nutrient loads to streams and rivers, but today hydromorphological alterations are considered increasingly implicated when lowland streams do not achieve good ecological status. Here, we explore if trait-abundance patterns of aquatic plants change along gradients in hydromorphological degradation and eutrophication in lowland stream sites located in Denmark. Specifically, we hypothesised that: i) changes in trait-abundance patterns occur along gradients in hydromorphological degradation and ii) trait-abundance patterns can serve to disentangle effects of eutrophication and hydromorphological degradation in lowland streams reflecting that the mechanisms behind changes differ. We used monitoring data from a total of 147 stream reaches with combined data on aquatic plant species abundance, catchment land use, hydromorphological alterations (i.e. planform, cross section, weed cutting) and water chemistry parameters. Traits related to life form, dispersal, reproduction and survival together with ecological preference values for nutrients and light (Ellenberg N and L) were allocated to 41 species representing 79% of the total species pool. We found clear evidence that habitat degradation (hydromorphological alterations and eutrophication) mediated selective changes in the trait-abundance patterns of the plant community. Specific traits could distinguish hydromorphological degradation (free-floating, surface; anchored floating leaves; anchored heterophylly) from eutrophication (free-floating, submerged; leaf area). We provide a conceptual framework for interpretation of how eutrophication and hydromorphological degradation interact and how this is reflected in trait-abundance patterns in aquatic plant communities in lowland streams. Our findings support the merit of trait-based approaches in biomonitoring as they shed light on mechanisms controlling structural changes under environmental

  15. Can lowland dry forests represent a refuge from avian malaria for native Hawaiian birds?

    USGS Publications Warehouse

    Tucker-Mohl, Katherine; Hart, Patrick; Atkinson, Carter T.

    2010-01-01

    Hawaii's native birds have become increasingly threatened over the past century. Introduced mosquito borne diseases such as avian malaria may be responsible for the near absence of endemic Hawaiian forest birds in low-elevation habitats. The recent recognition that some native Hawaiian forest birds may be repopulating moist lowland habitats as a result of evolved resistance to this disease has increased the conservation value of these areas. Here, we investigate whether remnant low elevation dry forests on Hawaii Island provide natural 'refuges' from mosquito-transmitted malaria by nature of their low rainfall and absence of suitable natural sources of water for mosquito breeding. Unlike lowland wet forests where high rates of disease transmission may be selecting for disease resistance, lowland dry forests may provide some refuge for native forest birds without natural resistance to malaria. We mistnetted forest birds in two lowland dry forests and tested all native birds by microscopy and serology for avian malaria caused by the Plasmodium relictum parasite. We also conducted surveys for standing water and mosquito larvae. Overall prevalence of infections with Plasmodium relictum in the Hawaii Amakihi Hemignathus virens virens was 15%. Most infected birds had lowlevel parasitemias, suggesting chronic infections. Although avian malaria is present in these lowland dry forest Amakihi populations, infection rates are significantly lower than in wet forest populations at similar elevations. Sources of breeding mosquitoes in these forests appeared to be largely anthropogenic; thus, there is potential to manage dry forests as mosquito-free habitat for Hawaii Amakihi and other Hawaiian forest birds.

  16. Greenhouse gas emissions and global warming potential of traditional and diversified tropical rice rotation systems.

    PubMed

    Weller, Sebastian; Janz, Baldur; Jörg, Lena; Kraus, David; Racela, Heathcliff S U; Wassmann, Reiner; Butterbach-Bahl, Klaus; Kiese, Ralf

    2016-01-01

    Global rice agriculture will be increasingly challenged by water scarcity, while at the same time changes in demand (e.g. changes in diets or increasing demand for biofuels) will feed back on agricultural practices. These factors are changing traditional cropping patterns from double-rice cropping to the introduction of upland crops in the dry season. For a comprehensive assessment of greenhouse gas (GHG) balances, we measured methane (CH4 )/nitrous oxide (N2 O) emissions and agronomic parameters over 2.5 years in double-rice cropping (R-R) and paddy rice rotations diversified with either maize (R-M) or aerobic rice (R-A) in upland cultivation. Introduction of upland crops in the dry season reduced irrigation water use and CH4 emissions by 66-81% and 95-99%, respectively. Moreover, for practices including upland crops, CH4 emissions in the subsequent wet season with paddy rice were reduced by 54-60%. Although annual N2 O emissions increased two- to threefold in the diversified systems, the strong reduction in CH4 led to a significantly lower (P < 0.05) annual GWP (CH4  + N2 O) as compared to the traditional double-rice cropping system. Measurements of soil organic carbon (SOC) contents before and 3 years after the introduction of upland crop rotations indicated a SOC loss for the R-M system, while for the other systems SOC stocks were unaffected. This trend for R-M systems needs to be followed as it has significant consequences not only for the GWP balance but also with regard to soil fertility. Economic assessment showed a similar gross profit span for R-M and R-R, while gross profits for R-A were reduced as a consequence of lower productivity. Nevertheless, regarding a future increase in water scarcity, it can be expected that mixed lowland-upland systems will expand in SE Asia as water requirements were cut by more than half in both rotation systems with upland crops. PMID:26386203

  17. Identification of Drought Tolerance Markers in a Diverse Population of Rice Cultivars by Expression and Metabolite Profiling

    PubMed Central

    Degenkolbe, Thomas; Do, Phuc T.; Kopka, Joachim; Zuther, Ellen; Hincha, Dirk K.; Köhl, Karin I.

    2013-01-01

    Rice provides about half of the calories consumed in Asian countries, but its productivity is often reduced by drought, especially when grown under rain-fed conditions. Cultivars with increased drought tolerance have been bred over centuries. Slow selection for drought tolerance on the basis of phenotypic traits may be accelerated by using molecular markers identified through expression and metabolic profiling. Previously, we identified 46 candidate genes with significant genotype × environment interaction in an expression profiling study on four cultivars with contrasting drought tolerance. These potential markers and in addition GC-MS quantified metabolites were tested in 21 cultivars from both indica and japonica background that varied in drought tolerance. Leaf blades were sampled from this population of cultivars grown under control or long-term drought condition and subjected to expression analysis by qRT-PCR and metabolite profiling. Under drought stress, metabolite levels correlated mainly negatively with performance parameters, but eight metabolites correlated positively. For 28 genes, a significant correlation between expression level and performance under drought was confirmed. Negative correlations were predominant. Among those with significant positive correlation was the gene coding for a cytosolic fructose-1,6-bisphosphatase. This enzyme catalyzes a highly regulated step in C-metabolism. The metabolic and transcript marker candidates for drought tolerance were identified in a highly diverse population of cultivars. Thus, these markers may be used to select for tolerance in a wide range of rice germplasms. PMID:23717458

  18. Impacts of management alternatives on rice yield and nitrogen losses to the environment: A case study in rural Sri Lanka.

    PubMed

    Stone, Elizabeth C; Hornberger, George M

    2016-01-15

    Maintaining crop yields is vital as populations increase, but environmental degradation resulting from cultivation must be prevented. In particular, freshwater resources are at risk of nitrate leaching from superfluous fertilization. This research explores the tradeoffs between maximizing yield and limiting environmental impacts of rice production in Sri Lanka. The DeNitrification-DeComposition (DNDC) model was used to examine how various combinations of fertilization and irrigation management affect yield, nitrous oxide (N2O) emissions, and nitrogen (N) leaching in paddy systems under climate and soil conditions in the dry zone of Sri Lanka from 1991 to 2010. Simulated fertilizer application rates ranged from zero to 2700 kgN/ha and simulated irrigation schemes were continuously flooded, marginally flooded, and rain-fed. Increasing fertilizer levels from zero to 300 kgN/ha per year increased yield but application of fertilizer beyond that amount ceased to affect yield for any of the three irrigation schemes. The combination of management options for obtaining the maximum grain yield, near 9000 kgC/ha, with the greatest amount of N uptake and relatively low nitrate leaching was using 225 kgN/ha under a continuously flooded regime. This research explores how cultivation in rice-growing regions in south Asia affects the environment and the N cycle, and demonstrates how informed management of these systems can reduce external inputs of N fertilizer without impacting yield. PMID:26519587

  19. Soil Incorporation of Silica-Rich Rice Husk Decreases Inorganic Arsenic in Rice Grain.

    PubMed

    Seyfferth, Angelia L; Morris, Andrew H; Gill, Rattandeep; Kearns, Kelli A; Mann, Jessica N; Paukett, Michelle; Leskanic, Corey

    2016-05-18

    Arsenic decreases rice yield, and inorganic grain As threatens human health; thus, strategies to decrease rice As are critically needed. Increased plant-available silica (Si) can decrease rice As, yet the source of Si matters. Rice husk, an underutilized and Si-rich byproduct of rice production that contains less labile C and an order of magnitude less As than rice straw, may be an economically viable Si resource to decrease rice As, yet the impact of rice husk incorporation on As in the rice-soil nexus has not been reported. This proof-of-concept study shows that rice husk incorporation to soil (1% w/w) decreases inorganic grain As by 25-50% without negatively affecting grain Cd, yield, or dissolved CH4 levels. Rice husk is a critical yet perhaps overlooked resource to improve soil quality through enhanced nutrient availability and attenuate human health risks through consumption of As-laden grain. PMID:27109244

  20. Rice scene radiation research plan

    NASA Technical Reports Server (NTRS)

    Heilman, J.

    1982-01-01

    Data requirements, tasks to be accomplished, and the technical approaches to be used in identifying the characteristics of rice for crop inventories are listed as well as methods for estimating crop development and assessing its conditions.

  1. Rice Reoviruses in Insect Vectors.

    PubMed

    Wei, Taiyun; Li, Yi

    2016-08-01

    Rice reoviruses, transmitted by leafhopper or planthopper vectors in a persistent propagative manner, seriously threaten the stability of rice production in Asia. Understanding the mechanisms that enable viral transmission by insect vectors is a key to controlling these viral diseases. This review describes current understanding of replication cycles of rice reoviruses in vector cell lines, transmission barriers, and molecular determinants of vector competence and persistent infection. Despite recent breakthroughs, such as the discoveries of actin-based tubule motility exploited by viruses to overcome transmission barriers and mutually beneficial relationships between viruses and bacterial symbionts, there are still many gaps in our knowledge of transmission mechanisms. Advances in genome sequencing, reverse genetics systems, and molecular technologies will help to address these problems. Investigating the multiple interaction systems among the virus, insect vector, insect symbiont, and plant during natural infection in the field is a central topic for future research on rice reoviruses. PMID:27296147

  2. Hazards Associated with High Altitude Rain-Fed Lakes (HARL) in the Overdeepened Deglaciated Region of Hindu Kush and Himalaya

    NASA Astrophysics Data System (ADS)

    Haritashya, U. K.; Hess, T. G.

    2014-12-01

    Mountain regions are changing rapidly as a result of climate change. It has been well established that these mountain regions are experiencing rapid glacier retreat. With accelerated retreat, glacial melt runoff can accumulate in an overdeepened glacier bed left behind by the receding glacier and can be bound by the walls of unstable frontal and lateral moraines to form a hazardous lake. However, when smaller glaciers retreat and downwaste they no longer contain enough ice to sustain the flow of water and maintain level of the lake. Furthermore, some smaller glaciers in the Hindu Kush and Himalayan region are observing extreme downwasting, which are either turning them into a rock glacier or heavily debris covered glacier leading to the reduced ice melt. Consequently, it is important to study these overdeepened beds, which are contained by the unstable mass. This is especially significant considering the great degree of complexity in the mountain weather system and recent examples of high intensity and short duration rainfall in the Hindu Kush region of Afghanistan, Karakoram region of Pakistan, and Central Himalayan region of India and Nepal. A precise understanding of mountain climate system is necessary, but so does these potentially deglaciated overdeepened beds where rain-fed lakes can form and increase systems hydrostatic pressure that can breach moraine containment and flood entire downstream region. Once lake has formed it possesses hydrological characteristics that are similar to the glacial lakes, which are known to put lives and infrastructure in danger. Therefore, in this study we evaluated overdeepened beds that are located in the complex topography and contained by abandoned or unstable lateral moraine using field and remote sensing satellite images. Our results provide degree of failure associated with these lakes based on the complex spatial and topological analysis as well as orographic distribution of the region. Such studies are not common in the

  3. Storage stability of flour-blasted brown rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Brown rice was blasted with rice flour rather than sand in a sand blaster to make microscopic nicks and cuts so that water can easily penetrate into the brown rice endosperm and cook the rice in a shorter time. The flour-blasted American Basmati brown rice, long grain brown rice, and parboiled long...

  4. Differentiation of weedy traits in ALS-resistant red rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice is a weedy form of cultivated rice (Oryza sativa) that competes aggressively with rice in the southern U.S., reduces yields and contaminates rice grains. The introduction of ClearfieldTM rice, a nontransgenic, herbicide-resistant rice cultivar a decade ago has led to increased use of imazet...

  5. Detection algorithm for multiple rice seeds images

    NASA Astrophysics Data System (ADS)

    Cheng, F.; Ying, Y. B.

    2006-10-01

    The objective of this research is to develop a digital image analysis algorithm for detection of multiple rice seeds images. The rice seeds used for this study involved a hybrid rice seed variety. Images of multiple rice seeds were acquired with a machine vision system for quality inspection of bulk rice seeds, which is designed to inspect rice seeds on a rotating disk with a CCD camera. Combining morphological operations and parallel processing gave improvements in accuracy, and a reduction in computation time. Using image features selected based on classification ability; a highly acceptable defects classification was achieved when the algorithm was implemented for all the samples to test the adaptability.

  6. Regulated Expression of a Cytokinin Biosynthesis Gene IPT Delays Leaf Senescence and Improves Yield under Rainfed and Irrigated Conditions in Canola (Brassica napus L.)

    PubMed Central

    Kant, Surya; Burch, David; Badenhorst, Pieter; Palanisamy, Rajasekaran; Mason, John; Spangenberg, German

    2015-01-01

    Delay of leaf senescence through genetic modification can potentially improve crop yield, through maintenance of photosynthetically active leaves for a longer period. Plant growth hormones such as cytokinin regulate and delay leaf senescence. Here, the structural gene (IPT) encoding the cytokinin biosynthetic enzyme isopentenyltransferase was fused to a functionally active fragment of the AtMYB32 promoter and was transformed into canola plants. Expression of the AtMYB32xs::IPT gene cassette delayed the leaf senescence in transgenic plants grown under controlled environment conditions and field experiments conducted for a single season at two geographic locations. The transgenic canola plants retained higher chlorophyll levels for an extended period and produced significantly higher seed yield with similar growth and phenology compared to wild type and null control plants under rainfed and irrigated treatments. The yield increase in transgenic plants was in the range of 16% to 23% and 7% to 16% under rainfed and irrigated conditions, respectively, compared to control plants. Most of the seed quality parameters in transgenic plants were similar, and with elevated oleic acid content in all transgenic lines and higher oil content and lower glucosinolate content in one specific transgenic line as compared to control plants. The results suggest that by delaying leaf senescence using the AtMYB32xs::IPT technology, productivity in crop plants can be improved under water stress and well-watered conditions. PMID:25602960

  7. A modelling approach to evaluate the long-term effect of soil texture on spring wheat productivity under a rain-fed condition

    PubMed Central

    He, Yong; Hou, Lingling; Wang, Hong; Hu, Kelin; McConkey, Brian

    2014-01-01

    Soil surface texture is an important environmental factor that influences crop productivity because of its direct effect on soil water and complex interactions with other environmental factors. Using 30-year data, an agricultural system model (DSSAT-CERES-Wheat) was calibrated and validated. After validation, the modelled yield and water use (WU) of spring wheat (Triticum aestivum L.) from two soil textures (silt loam and clay) under rain-fed condition were analyzed. Regression analysis showed that wheat grown in silt loam soil is more sensitive to WU than wheat grown in clay soil, indicating that the wheat grown in clay soil has higher drought tolerance than that grown in silt loam. Yield variation can be explained by WU other than by precipitation use (PU). These results demonstrated that the DSSAT-CERES-Wheat model can be used to evaluate the WU of different soil textures and assess the feasibility of wheat production under various conditions. These outcomes can improve our understanding of the long-term effect of soil texture on spring wheat productivity in rain-fed condition. PMID:25074796

  8. A comparison of water use and water-use-efficiency of maize and biomass sorghum in the rain-fed, Midwestern, US.

    NASA Astrophysics Data System (ADS)

    Roby, M.; Salas Fernandez, M.; VanLoocke, A. D.

    2014-12-01

    There is growing consensus among model projections that climate change may increase the frequency and intensity of drought in the rain-fed, maize-dominated, Midwestern US. Uncertainty in the availability of water, combined with an increased demand for non-grain ethanol feedstock, may necessitate expanding the production of more water-use-efficient and less drought sensitive crops for biomass applications. Research suggests that biomass sorghum [Sorghum bicolor (L.) Moench] is more drought tolerant and can produce more biomass than maize in water-limiting environments; however, sorghum water use data are limited for the rain-fed Midwestern US. To address this gap, a replicated (n=3) side-by-side trial was established in Ames, Iowa to determine cumulative water use and water-use-efficiency of maize and biomass sorghum. Data were collected by micrometeorological stations located in the center of each plot and used to calculate cumulative evapotranspiration throughout the 2014 growing season using the residual energy balance method. Continuous micrometeorological measurements were supplemented by periodic measurements of leaf area index (LAI) and above-ground biomass. At mid-point of the growing season, preliminary data analysis revealed similar water use for sorghum and maize. Data collection will continue for the remainder of the growing season, at which point a stronger conclusion can be drawn. This research will provide important insight on the potential hydrologic effects of expanding biomass sorghum production in the Midwestern, US.

  9. Productivity and sustainability of rainfed wheat-soybean system in the North China Plain: results from a long-term experiment and crop modelling

    PubMed Central

    Qin, Wei; Wang, Daozhong; Guo, Xisheng; Yang, Taiming; Oenema, Oene

    2015-01-01

    A quantitative understanding of yield response to water and nutrients is key to improving the productivity and sustainability of rainfed cropping systems. Here, we quantified the effects of rainfall, fertilization (NPK) and soil organic amendments (with straw and manure) on yields of a rainfed wheat-soybean system in the North China Plain (NCP), using 30-years’ field experimental data (1982–2012) and the simulation model-AquaCrop. On average, wheat and soybean yields were 5 and 2.5 times higher in the fertilized treatments than in the unfertilized control (CK), respectively. Yields of fertilized treatments increased and yields of CK decreased over time. NPK + manure increased yields more than NPK alone or NPK + straw. The additional effect of manure is likely due to increased availability of K and micronutrients. Wheat yields were limited by rainfall and can be increased through soil mulching (15%) or irrigation (35%). In conclusion, combined applications of fertilizer NPK and manure were more effective in sustaining high crop yields than recommended fertilizer NPK applications. Manure applications led to strong accumulation of NPK and relatively low NPK use efficiencies. Water deficiency in wheat increased over time due to the steady increase in yields, suggesting that the need for soil mulching increases. PMID:26627707

  10. A modelling approach to evaluate the long-term effect of soil texture on spring wheat productivity under a rain-fed condition.

    PubMed

    He, Yong; Hou, Lingling; Wang, Hong; Hu, Kelin; McConkey, Brian

    2014-01-01

    Soil surface texture is an important environmental factor that influences crop productivity because of its direct effect on soil water and complex interactions with other environmental factors. Using 30-year data, an agricultural system model (DSSAT-CERES-Wheat) was calibrated and validated. After validation, the modelled yield and water use (WU) of spring wheat (Triticum aestivum L.) from two soil textures (silt loam and clay) under rain-fed condition were analyzed. Regression analysis showed that wheat grown in silt loam soil is more sensitive to WU than wheat grown in clay soil, indicating that the wheat grown in clay soil has higher drought tolerance than that grown in silt loam. Yield variation can be explained by WU other than by precipitation use (PU). These results demonstrated that the DSSAT-CERES-Wheat model can be used to evaluate the WU of different soil textures and assess the feasibility of wheat production under various conditions. These outcomes can improve our understanding of the long-term effect of soil texture on spring wheat productivity in rain-fed condition. PMID:25074796

  11. Productivity and sustainability of rainfed wheat-soybean system in the North China Plain: results from a long-term experiment and crop modelling.

    PubMed

    Qin, Wei; Wang, Daozhong; Guo, Xisheng; Yang, Taiming; Oenema, Oene

    2015-01-01

    A quantitative understanding of yield response to water and nutrients is key to improving the productivity and sustainability of rainfed cropping systems. Here, we quantified the effects of rainfall, fertilization (NPK) and soil organic amendments (with straw and manure) on yields of a rainfed wheat-soybean system in the North China Plain (NCP), using 30-years' field experimental data (1982-2012) and the simulation model-AquaCrop. On average, wheat and soybean yields were 5 and 2.5 times higher in the fertilized treatments than in the unfertilized control (CK), respectively. Yields of fertilized treatments increased and yields of CK decreased over time. NPK + manure increased yields more than NPK alone or NPK + straw. The additional effect of manure is likely due to increased availability of K and micronutrients. Wheat yields were limited by rainfall and can be increased through soil mulching (15%) or irrigation (35%). In conclusion, combined applications of fertilizer NPK and manure were more effective in sustaining high crop yields than recommended fertilizer NPK applications. Manure applications led to strong accumulation of NPK and relatively low NPK use efficiencies. Water deficiency in wheat increased over time due to the steady increase in yields, suggesting that the need for soil mulching increases. PMID:26627707

  12. Kennedy at Rice University

    NASA Technical Reports Server (NTRS)

    1962-01-01

    President Kennedy speaks before a crowd of 35,000 people at Rice University in the football field. The following are excerpts from his speech. ' ...We set sail on his new sea because there is a new knowledge to be gained, and new rights to be won, and they must be won and used for the progress of all people. ...Whether it will become a force for good or ill depends on man, and only if the United States occupies a position of pre-eminence can we help decide whether this new ocean will be a sea of peace or a new terrifying theater of war. But I do say space can be explored and mastered without feeding the fires of war, without repeating the mistakes that man has made with extending his writ around this globe of ours. ...There is no strife, no prejudice, no national conflict in outer space as yet. Its conquest deserves the best of all mankind, and its opportunity for peaceful cooperation may never come again. But why, some say the Moon? Why choose this as our goal? And they may well ask, why climb the highest mountian? Why - 35 years ago - why fly the Atlantic? Why does Rice play Texas? We choose to go to the Moon, we choose to go to the Moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one in which we intend to win, and the others too.'

  13. Kennedy at Rice University

    NASA Technical Reports Server (NTRS)

    1962-01-01

    President Kennedy speaks before a crowd of 35,000 people at Rice University in the football field. The following are excerpts from his speech. ' ...We set sail on his new sea because there is a new knowledge to begained, and new rights to be won, and they must be won and used for the progress of all people. Whether it will become a force for good or ill depends on man, and only if the United States occupies a position of pre-eminence can we help decide whether this new ocean will be a sea of peace or a new terrifying theater of war. But I do say space can be explored and mastered without feeding the fires of war, without repeating the mistakes that man has made with extending his wirt around this globe of ours. There is no strife, no prejudice, no national conflict in outer space as yet. Its conquest deserves the best of all mankind, and its opportunity for peaceful cooperation may never come again. But why, some say the Moon? Why choose this as our goal? And they may well ask, why climb the highest mountain? Why 35 years ago why fly the Atlantic? Why does Rice play Texas? We choose to go to the Moon, we choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one in which we attend to win, and the others , too.'

  14. Outcrossing potential between U.S. red rice (Oryza sativa) and Chinese indica rice (Oryza sativa) lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice in southern U.S. rice fields remains a widespread, economically challenging problem despite nearly a decade of rice production systems that include true-breeding rice cultivars and indica-derived hybrid rice with resistance to imazethapyr. Both of these herbicide-resistant rice systems hav...

  15. Red rice (Oryza sativa L.) emergence characteristics and influence on rice (O. sativa) yield at different planting dates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivated rice yield losses due to red rice infestation vary by cultivar, red rice density, and duration of interference. The competition effects of red rice could be influenced further by emergence characteristics, red rice biotype, and planting time of cultivated rice. We aimed to characterize th...

  16. Mars: the evolutionary history of the northern lowlands based on crater counting and geologic mapping

    USGS Publications Warehouse

    Werner, S.C.; Tanaka, K.L.; Skinner, J.A., Jr.

    2011-01-01

    The geologic history of planetary surfaces is most effectively determined by joining geologic mapping and crater counting which provides an iterative, qualitative and quantitative method for defining relative ages and absolute model ages. Based on this approach, we present spatial and temporal details regarding the evolution of the Martian northern plains and surrounding regions. The highland–lowland boundary (HLB) formed during the pre-Noachian and was subsequently modified through various processes. The Nepenthes Mensae unit along the northern margins of the cratered highlands, was formed by HLB scarp-erosion, deposition of sedimentary and volcanic materials, and dissection by surface runoff between 3.81 and 3.65 Ga. Ages for giant polygons in Utopia and Acidalia Planitiae are ~ 3.75 Ga and likely reflect the age of buried basement rocks. These buried lowland surfaces are comparable in age to those located closer to the HLB, where a much thinner, post-HLB deposit is mapped. The emplacement of the most extensive lowland surfaces ended between 3.75 and 3.4 Ga, based on densities of craters generally View the MathML source> 3 km in diameter. Results from the polygonal terrain support the existence of a major lowland depocenter shortly after the pre-Noachian formation of the northern lowlands. In general, northern plains surfaces show gradually younger ages at lower elevations, consistent local to regional unit emplacement and resurfacing between 3.6 and 2.6 Ga. Elevation levels and morphology are not necessarily related, and variations in ages within the mapped units are found, especially in units formed and modified by multiple geological processes. Regardless, most of the youngest units in the northern lowlands are considered to be lavas, polar ice, or thick mantle deposits, arguing against the ocean theory during the Amazonian Period (younger than about 3.15 Ga). All ages measured in the closest vicinity of the steep dichotomy escarpment are also 3.7 Ga or

  17. Mars: The evolutionary history of the northern lowlands based on crater counting and geologic mapping

    NASA Astrophysics Data System (ADS)

    Werner, S. C.; Tanaka, K. L.; Skinner, J. A.

    2011-09-01

    The geologic history of planetary surfaces is most effectively determined by joining geologic mapping and crater counting which provides an iterative, qualitative and quantitative method for defining relative ages and absolute model ages. Based on this approach, we present spatial and temporal details regarding the evolution of the Martian northern plains and surrounding regions. The highland-lowland boundary (HLB) formed during the pre-Noachian and was subsequently modified through various processes. The Nepenthes Mensae unit along the northern margins of the cratered highlands, was formed by HLB scarp-erosion, deposition of sedimentary and volcanic materials, and dissection by surface runoff between 3.81 and 3.65 Ga. Ages for giant polygons in Utopia and Acidalia Planitiae are ˜ 3.75 Ga and likely reflect the age of buried basement rocks. These buried lowland surfaces are comparable in age to those located closer to the HLB, where a much thinner, post-HLB deposit is mapped. The emplacement of the most extensive lowland surfaces ended between 3.75 and 3.4 Ga, based on densities of craters generally >3km in diameter. Results from the polygonal terrain support the existence of a major lowland depocenter shortly after the pre-Noachian formation of the northern lowlands. In general, northern plains surfaces show gradually younger ages at lower elevations, consistent local to regional unit emplacement and resurfacing between 3.6 and 2.6 Ga. Elevation levels and morphology are not necessarily related, and variations in ages within the mapped units are found, especially in units formed and modified by multiple geological processes. Regardless, most of the youngest units in the northern lowlands are considered to be lavas, polar ice, or thick mantle deposits, arguing against the ocean theory during the Amazonian Period (younger than about 3.15 Ga). All ages measured in the closest vicinity of the steep dichotomy escarpment are also 3.7 Ga or older. The formation ages of

  18. Holocene relative sea levels and related prehistoric activity in the Forth lowland, Scotland, United Kingdom

    NASA Astrophysics Data System (ADS)

    Smith, D. E.; Davies, M. H.; Brooks, C. L.; Mighall, T. M.; Dawson, S.; Rea, B. R.; Jordan, J. T.; Holloway, L. K.

    2010-08-01

    Changes in relative sea level (RSL) and their effect on the distribution of human activity in the Forth lowland, Scotland, UK between ca 11,700 and ca 2000 calibrated years before present (BP) are examined. Block uplift of shorelines occurred over a longer period than previously thought, continuing to at least around 4700 BP. New graphs of RSL change, based upon an analysis of previous work and evidence from new sites using standard morphological and stratigraphical analyses, support a fall in RSL in the early Holocene during which buried estuarine surfaces were formed, followed by a marked reversal on a centennial, perhaps even decadal, scale sometime around 9900-9500 BP from a falling sequence to a rising one. There may have been a short-lived fluctuation in the rising RSL ca 8300 BP, and the Holocene Storegga Slide tsunami of ca 8100 BP was widespread in the lowland. The rising RSL culminated at the Main Postglacial Shoreline, reached ca 7800 BP, when Mean High Water Spring Tides (MHWS) lay within the range 14.6-16.5 m British Ordnance Datum (OD) in the western lowland. This is the highest published Holocene RSL in Britain and Ireland. The subsequent fall in RSL stabilised at a second shoreline, the Blairdrummond Shoreline, from which regression was occurring at ca 4700 BP. RSL later fell to a lower shoreline at ca 3900 BP before reaching present levels within the last three millennia. Comparison between the empirical evidence for RSL change in this area and glacial isostatic adjustment models indicates both similarities and differences. Records of archaeological sites and artefacts in the lowland and surrounding areas are discussed. Maps showing the evolution of the estuary are compared with the distribution of Mesolithic, Neolithic, Bronze Age and Iron Age activity. Evidence for Mesolithic people indicates the opportunistic use of available resources as RSL rose and the estuary expanded to its maximum extent. Neolithic people were also attracted to the estuary

  19. Processing Conditions, Rice Properties, Health and Environment

    PubMed Central

    Roy, Poritosh; Orikasa, Takahiro; Okadome, Hiroshi; Nakamura, Nobutaka; Shiina, Takeo

    2011-01-01

    Rice is the staple food for nearly two-thirds of the world’s population. Food components and environmental load of rice depends on the rice form that is resulted by different processing conditions. Brown rice (BR), germinated brown rice (GBR) and partially-milled rice (PMR) contains more health beneficial food components compared to the well milled rice (WMR). Although the arsenic concentration in cooked rice depends on the cooking methods, parboiled rice (PBR) seems to be relatively prone to arsenic contamination compared to that of untreated rice, if contaminated water is used for parboiling and cooking. A change in consumption patterns from PBR to untreated rice (non-parboiled), and WMR to PMR or BR may conserve about 43–54 million tons of rice and reduce the risk from arsenic contamination in the arsenic prone area. This study also reveals that a change in rice consumption patterns not only supply more food components but also reduces environmental loads. A switch in production and consumption patterns would improve food security where food grains are scarce, and provide more health beneficial food components, may prevent some diseases and ease the burden on the Earth. However, motivation and awareness of the environment and health, and even a nominal incentive may require for a method switching which may help in building a sustainable society. PMID:21776212

  20. Molecular dynamics of interactions of rice with rice blast and sheath blight pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In an effort to develop the molecular strategies to control rice (Oryzae sativa) diseases, molecular interactions of rice with rice blast [Magnaporthe oryzae, formerly (Magnaporthe grisea] and sheath blight (Rhizoctonia solani) fungi were analyzed. The interaction of rice with M. oryzae follows a b...

  1. Factors influencing ALS-resistant gene transfer from CL (tm) rice to red rice.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice (Oryza sativa L.) is hard to control due to its genetic similarity to cultivated rice. Herbicide-resistant Clearfield ™ (CL) rice now offers an excellent option for red rice control. However, sustainability of CL technology at the producers’ level will be dictated by various factors. Promi...

  2. The impact of planting date on management of the rice water weevil in Louisiana rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rice water weevil, Lissorhoptrus oryzophilus, is the most destructive insect pest of rice in the United States. Early planting of rice to avoid damaging infestations of the rice water weevil has long been suggested as a management tactic. A five-year study was conducted to characterize the influ...

  3. Diversity of global rice markets and the science required for consumer-targeted rice breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the ever-increasing global demand for high quality rice in both local production regions and with Western consumers, we have a strong desire to understand better the importance of different quality traits that make up the rice grain and obtain a full picture of rice quality demographics. Rice ...

  4. Genetic diversity for rice grain mineral concentrations observed among genetically and geographically giverse rice accessions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With about half of the world’s people dependent on rice as their main food source, improving the nutritional value of rice could have major impact on human health. While rice in the USA is often artificially fortified, natural enhancement of the rice grain’s nutritional value, i.e. from genetic impr...

  5. Volatiles induction in rice stink bug host grasses and rice plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice stink bug (RSB), Oebalus pugnax F., is an important pest of heading rice in the United States. Little is known about plant volatiles production following herbivory by the rice stink bug. RSB feeding induced volatiles production in different RSB host grasses and rice varieties, and may help expl...

  6. [High proliferation of An. gambiae and An. funestus larvae in irrigated and non-irrigated rice fields in the Western forest region of Côte-d'Ivoire].

    PubMed

    Betsi, A N; Tchicaya, E S; Koudou, B G

    2012-08-01

    Entomological surveys were conducted in the forest region of western Côte-d'Ivoire from November 1998 to December 1999 in order to study the ecology of mosquito breeding sites and bioecology of Culicidae. Three following agro-systems were considered: landscaped lowland (R0), the lowland with one growing season of rice per year (R1) and the lowland with two seasonal production of irrigated rice field per year (R2). Two villages were selected by agro-system, and cross-sectional entomological surveys were conducted every six weeks in each village. A total of 5,839 larvae of mosquitoes were collected in the different categories of breeding sites surveyed. From these larvae, 2,199 imagos emerged, giving an emergence rate equal to 37.7%. Nine species belonging to three genera were identified. The genus Anopheles with 1,828 larvae represented 83.1% of the total. Five anophelinae species were identified. An. ziemanni was the most abundant species with 751 larvae (32.5% of the total). An. funestus with 531 larvae represented 24.1% of the total. Larvae from this species were collected in river with raised vegetation and in irrigated rice field at transplanting and cut stages. About 559 larvae of An. gambiae representing 25.4% of the total were collected from artificial breeding sites, particularly in rice fields after the planting stage. Additionally, 38,626 anthropophilic mosquitoes were collected on 936 mannight catches in the study area. Thirty species belonging to seven genera were identified in the three agro-systems. In the villages of the agro-system R0, 2,675 mosquitoes were collected on landing catches. In the villages of the agro-ecosystem R1, 11,311 mosquitoes were collected, which was 4.2 higher than the number collected in the village of agro-system R0 for the same sampling effort. In the village of the agro-system R2, 24,640 mosquitoes were collected, which was 9.2 higher than the number collected in the agro-system R0 and 2.2 higher than the number collected

  7. QTL Mapping in Three Rice Populations Uncovers Major Genomic Regions Associated with African Rice Gall Midge Resistance

    PubMed Central

    Semagn, Kassa; Sow, Mounirou; Nwilene, Francis; Kolade, Olufisayo; Bocco, Roland; Oyetunji, Olumoye; Mitchell-Olds, Thomas; Ndjiondjop, Marie-Noëlle

    2016-01-01

    African rice gall midge (AfRGM) is one of the most destructive pests of irrigated and lowland African ecologies. This study aimed to identify the quantitative trait loci (QTL) associated with AfRGM pest incidence and resistance in three independent bi-parental rice populations (ITA306xBW348-1, ITA306xTOG7106 and ITA306xTOS14519), and to conduct meta QTL (mQTL) analysis to explore whether any genomic regions are conserved across different genetic backgrounds. Composite interval mapping (CIM) conducted on the three populations independently uncovered a total of 28 QTLs associated with pest incidence (12) and pest severity (16). The number of QTLs per population associated with AfRGM resistance varied from three in the ITA306xBW348-1 population to eight in the ITA306xTOG7106 population. Each QTL individually explained 1.3 to 34.1% of the phenotypic variance. The major genomic region for AfRGM resistance had a LOD score and R2 of 60.0 and 34.1% respectively, and mapped at 111 cM on chromosome 4 (qAfrGM4) in the ITA306xTOS14519 population. The meta-analysis reduced the number of QTLs from 28 to 17 mQTLs, each explaining 1.3 to 24.5% of phenotypic variance, and narrowed the confidence intervals by 2.2 cM. There was only one minor effect mQTL on chromosome 1 that was common in the TOS14519 and TOG7106 genetic backgrounds; all other mQTLs were background specific. We are currently fine-mapping and validating the major effect genomic region on chromosome 4 (qAfRGM4). This is the first report in mapping the genomic regions associated with the AfRGM resistance, and will be highly useful for rice breeders. PMID:27508500

  8. QTL Mapping in Three Rice Populations Uncovers Major Genomic Regions Associated with African Rice Gall Midge Resistance.

    PubMed

    Yao, Nasser; Lee, Cheng-Ruei; Semagn, Kassa; Sow, Mounirou; Nwilene, Francis; Kolade, Olufisayo; Bocco, Roland; Oyetunji, Olumoye; Mitchell-Olds, Thomas; Ndjiondjop, Marie-Noëlle

    2016-01-01

    African rice gall midge (AfRGM) is one of the most destructive pests of irrigated and lowland African ecologies. This study aimed to identify the quantitative trait loci (QTL) associated with AfRGM pest incidence and resistance in three independent bi-parental rice populations (ITA306xBW348-1, ITA306xTOG7106 and ITA306xTOS14519), and to conduct meta QTL (mQTL) analysis to explore whether any genomic regions are conserved across different genetic backgrounds. Composite interval mapping (CIM) conducted on the three populations independently uncovered a total of 28 QTLs associated with pest incidence (12) and pest severity (16). The number of QTLs per population associated with AfRGM resistance varied from three in the ITA306xBW348-1 population to eight in the ITA306xTOG7106 population. Each QTL individually explained 1.3 to 34.1% of the phenotypic variance. The major genomic region for AfRGM resistance had a LOD score and R2 of 60.0 and 34.1% respectively, and mapped at 111 cM on chromosome 4 (qAfrGM4) in the ITA306xTOS14519 population. The meta-analysis reduced the number of QTLs from 28 to 17 mQTLs, each explaining 1.3 to 24.5% of phenotypic variance, and narrowed the confidence intervals by 2.2 cM. There was only one minor effect mQTL on chromosome 1 that was common in the TOS14519 and TOG7106 genetic backgrounds; all other mQTLs were background specific. We are currently fine-mapping and validating the major effect genomic region on chromosome 4 (qAfRGM4). This is the first report in mapping the genomic regions associated with the AfRGM resistance, and will be highly useful for rice breeders. PMID:27508500

  9. GENE FLOW BETWEEN RED RICE AND RICE IN HERBICIDE RESISTANT RICE FIELDS: EVALUATING RISKS AND MANAGEMENT OPTIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Imidazolinone (IMI)-resistant rice cultivars have been increasingly adopted in the southern U.S. since their initial introduction in 2002, largely due to the newly acquired control of red rice that is now possible in these systems. It is estimated that IMI rice is being grown on 20 to 25% of the ac...

  10. Multiple abiotic stimuli are integrated in the regulation of rice gene expression under field conditions

    PubMed Central

    Plessis, Anne; Hafemeister, Christoph; Wilkins, Olivia; Gonzaga, Zennia Jean; Meyer, Rachel Sarah; Pires, Inês; Müller, Christian; Septiningsih, Endang M; Bonneau, Richard; Purugganan, Michael

    2015-01-01

    Plants rely on transcriptional dynamics to respond to multiple climatic fluctuations and contexts in nature. We analyzed the genome-wide gene expression patterns of rice (Oryza sativa) growing in rainfed and irrigated fields during two distinct tropical seasons and determined simple linear models that relate transcriptomic variation to climatic fluctuations. These models combine multiple environmental parameters to account for patterns of expression in the field of co-expressed gene clusters. We examined the similarities of our environmental models between tropical and temperate field conditions, using previously published data. We found that field type and macroclimate had broad impacts on transcriptional responses to environmental fluctuations, especially for genes involved in photosynthesis and development. Nevertheless, variation in solar radiation and temperature at the timescale of hours had reproducible effects across environmental contexts. These results provide a basis for broad-based predictive modeling of plant gene expression in the field. DOI: http://dx.doi.org/10.7554/eLife.08411.001 PMID:26609814

  11. Can the co-cultivation of rice and fish help sustain rice production?

    PubMed

    Hu, Liangliang; Zhang, Jian; Ren, Weizheng; Guo, Liang; Cheng, Yongxu; Li, Jiayao; Li, Kexin; Zhu, Zewen; Zhang, Jiaen; Luo, Shiming; Cheng, Lei; Tang, Jianjun; Chen, Xin

    2016-01-01

    Because rice feeds half of the world's population, a secure global food supply depends on sustainable rice production. Here we test whether the co-cultivation of rice and fish into one "rice-fish system" (RFS; fish refers to aquatic animals in this article) could help sustain rice production. We examined intensive and traditional RFSs that have been widely practiced in China. We found that rice yields did not decrease when fish yield was below a threshold value in each intensive RFS. Below the thresholds, moreover, fish yields in intensive RFSs can be substantially higher than those in traditional RFS without reducing rice yield. Relative to rice monoculture, the use of fertilizer-nitrogen and pesticides decreased, and the farmers' net income increased in RFSs. The results suggest that RFSs can help sustain rice production, and suggest that development of co-culture technologies (i.e. proper field configuration for fish and rice) is necessary to achieve the sustainability. PMID:27349875

  12. Why are There So Few Magnetic Anomalies in Martian Lowlands and Basins?

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.; Aharonson, Oded; Banerdt, W. Bruce; Dombard, Andrew J.; Frey, Herbert V.; Golombek, Matthew P.; Hauck, Steven A., II; Head, James W., III; Johnson, Catherine L.; McGovern, Patrick J.

    2003-01-01

    The discovery of large areas of strongly magnetized crust on Mars [1,2] provides important information on the timing of both crustal and deeper interior processes on that planet. Critical to an understanding of that timing, as well as to the processes that have contributed to the magnetization and demagnetization of crustal materials, is the geographical distribution of magnetic anomalies discernible from spacecraft orbit. The paucity of resolved magnetic anomalies in the northern lowlands and within and surrounding the best-preserved major impact basins has been noted since the crustal field was first globally mapped [1], but no straightforward explanation of that full pattern has yet been offered. Here we suggest that ancient hydrothermal alteration of magnetic carriers in Martian lowlands and basins may have contributed to the magnetization distribution observed today.

  13. High-resolution lidar topography of the Puget Lowland, Washington - A bonanza for earth science

    USGS Publications Warehouse

    Haugerud, R.A.; Harding, D.J.; Johnson, S.Y.; Harless, J.L.; Weaver, C.S.; Sherrod, B.L.

    2003-01-01

    More than 10,000 km2 of high-resolution, public-domain topography acquired by the Puget Sound Lidar Consortium is revolutionizing investigations of active faulting, continental glaciation, landslides, and surficial processes in the seismically active Puget Lowland. The Lowland-the population and economic center of the Pacific Northwest-presents special problems for hazards investigations, with its young glacial topography, dense forest cover, and urbanization. Lidar mapping during leaf-off conditions has led to a detailed digital model of the landscape beneath the forest canopy. The surface thus revealed contains a rich and diverse record of previously unknown surface-rupturing faults, deep-seated landslides, uplifted Holocene and Pleistocene beaches, and subglacial and periglacial features. More than half a dozen suspected postglacial fault scarps have been identified to date. Five scarps that have been trenched show evidence of large, Holocene, surface-rupturing earthquakes.

  14. The lethal fungus Batrachochytrium dendrobatidis is present in lowland tropical forests of far eastern Panamá.

    PubMed

    Rebollar, Eria A; Hughey, Myra C; Harris, Reid N; Domangue, Rickie J; Medina, Daniel; Ibáñez, Roberto; Belden, Lisa K

    2014-01-01

    The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), is one of the main causes of amphibian population declines and extinctions all over the world. In the Neotropics, this fungal disease has caused catastrophic declines in the highlands as it has spread throughout Central America down to Panamá. In this study, we determined the prevalence and intensity of Bd infection in three species of frogs in one highland and four lowland tropical forests, including two lowland regions in eastern Panamá in which the pathogen had not been detected previously. Bd was present in all the sites sampled with a prevalence ranging from 15-34%, similar to other Neotropical lowland sites. The intensity of Bd infection on individual frogs was low, ranging from average values of 0.11-24 zoospore equivalents per site. Our work indicates that Bd is present in anuran communities in lowland Panamá, including the Darién province, and that the intensity of the infection may vary among species from different habitats and with different life histories. The population-level consequences of Bd infection in amphibian communities from the lowlands remain to be determined. Detailed studies of amphibian species from the lowlands will be essential to determine the reason why these species are persisting despite the presence of the pathogen. PMID:24740162

  15. The Lethal Fungus Batrachochytrium dendrobatidis Is Present in Lowland Tropical Forests of Far Eastern Panamá

    PubMed Central

    Rebollar, Eria A.; Hughey, Myra C.; Harris, Reid N.; Domangue, Rickie J.; Medina, Daniel; Ibáñez, Roberto; Belden, Lisa K.

    2014-01-01

    The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), is one of the main causes of amphibian population declines and extinctions all over the world. In the Neotropics, this fungal disease has caused catastrophic declines in the highlands as it has spread throughout Central America down to Panamá. In this study, we determined the prevalence and intensity of Bd infection in three species of frogs in one highland and four lowland tropical forests, including two lowland regions in eastern Panamá in which the pathogen had not been detected previously. Bd was present in all the sites sampled with a prevalence ranging from 15–34%, similar to other Neotropical lowland sites. The intensity of Bd infection on individual frogs was low, ranging from average values of 0.11–24 zoospore equivalents per site. Our work indicates that Bd is present in anuran communities in lowland Panamá, including the Darién province, and that the intensity of the infection may vary among species from different habitats and with different life histories. The population-level consequences of Bd infection in amphibian communities from the lowlands remain to be determined. Detailed studies of amphibian species from the lowlands will be essential to determine the reason why these species are persisting despite the presence of the pathogen. PMID:24740162

  16. Estimated fumonisin exposure in Guatemala is greatest in consumers of lowland maize.

    PubMed

    Torres, Olga A; Palencia, Edwin; Lopez de Pratdesaba, Ligia; Grajeda, Ruben; Fuentes, Mario; Speer, Marcy C; Merrill, Alfred H; O'Donnell, Kerry; Bacon, Charles W; Glenn, Anthony E; Riley, Ronald T

    2007-12-01

    Fumonisin mycotoxins contaminate maize worldwide. Analysis of maize samples (n = 396) collected from fields in Guatemala from 2000 to 2003 found that lowland maize (<360 m) had significantly more fumonisin B1 than highland maize (>1200 m). For example, 78% of the lowland samples collected at harvest in 2002 contained >0.3 microg/g of fumonisin B1, whereas only 2% of the highland samples contained >0.3 microg/g. Maize from the 2002 crop collected from storage in the highlands just before the 2003 harvest contained significantly more fumonisin B1 compared with levels at harvest in 2002. All Fusarium-infected kernels analyzed from 9 random lowland locations in 2001 were infected with fumonisin-producing Fusarium verticillioides and no other Fusarium species, whereas in samples from the highlands, only 5% of the Fusarium-positive kernels were F. verticillioides. In 2005, maize samples (n = 236) from the 2004 crop were collected from local markets in 20 Departments across Guatemala. The analysis showed that maize from lowland locations was often highly contaminated with fumonisin and was frequently transported to and sold in highland markets. Thus, fumonisin exposure in the highlands will be greatest in groups that obtain their maize in the market place from commercial vendors. Based on a recall study and published consumption data, a preliminary assessment of daily intake of total fumonisins was estimated. Consumption of nixtamalized maize products made from >50% of the maize from commercial vendors in 2005 could result in exposure exceeding the recommended WHO provisional maximal tolerable daily intake. PMID:18029490

  17. Thermokarst rates intensify due to climate change and forest fragmentation in an Alaskan boreal forest lowland.

    PubMed

    Lara, Mark J; Genet, Hélène; McGuire, Anthony D; Euskirchen, Eugénie S; Zhang, Yujin; Brown, Dana R N; Jorgenson, Mark T; Romanovsky, Vladimir; Breen, Amy; Bolton, William R

    2016-02-01

    Lowland boreal forest ecosystems in Alaska are dominated by wetlands comprised of a complex mosaic of fens, collapse-scar bogs, low shrub/scrub, and forests growing on elevated ice-rich permafrost soils. Thermokarst has affected the lowlands of the Tanana Flats in central Alaska for centuries, as thawing permafrost collapses forests that transition to wetlands. Located within the discontinuous permafrost zone, this region has significantly warmed over the past half-century, and much of these carbon-rich permafrost soils are now within ~0.5 °C of thawing. Increased permafrost thaw in lowland boreal forests in response to warming may have consequences for the climate system. This study evaluates the trajectories and potential drivers of 60 years of forest change in a landscape subjected to permafrost thaw in unburned dominant forest types (paper birch and black spruce) associated with location on elevated permafrost plateau and across multiple time periods (1949, 1978, 1986, 1998, and 2009) using historical and contemporary aerial and satellite images for change detection. We developed (i) a deterministic statistical model to evaluate the potential climatic controls on forest change using gradient boosting and regression tree analysis, and (ii) a 30 × 30 m land cover map of the Tanana Flats to estimate the potential landscape-level losses of forest area due to thermokarst from 1949 to 2009. Over the 60-year period, we observed a nonlinear loss of birch forests and a relatively continuous gain of spruce forest associated with thermokarst and forest succession, while gradient boosting/regression tree models identify precipitation and forest fragmentation as the primary factors controlling birch and spruce forest change, respectively. Between 1950 and 2009, landscape-level analysis estimates a transition of ~15 km² or ~7% of birch forests to wetlands, where the greatest change followed warm periods. This work highlights that the vulnerability and resilience of

  18. An interactive modelling tool for understanding hydrological processes in lowland catchments

    NASA Astrophysics Data System (ADS)

    Brauer, Claudia; Torfs, Paul; Uijlenhoet, Remko

    2016-04-01

    Recently, we developed the Wageningen Lowland Runoff Simulator (WALRUS), a rainfall-runoff model for catchments with shallow groundwater (Brauer et al., 2014ab). WALRUS explicitly simulates processes which are important in lowland catchments, such as feedbacks between saturated and unsaturated zone and between groundwater and surface water. WALRUS has a simple model structure and few parameters with physical connotations. Some default functions (which can be changed easily for research purposes) are implemented to facilitate application by practitioners and students. The effect of water management on hydrological variables can be simulated explicitly. The model description and applications are published in open access journals (Brauer et al, 2014). The open source code (provided as R package) and manual can be downloaded freely (www.github.com/ClaudiaBrauer/WALRUS). We organised a short course for Dutch water managers and consultants to become acquainted with WALRUS. We are now adapting this course as a stand-alone tutorial suitable for a varied, international audience. In addition, simple models can aid teachers to explain hydrological principles effectively. We used WALRUS to generate examples for simple interactive tools, which we will present at the EGU General Assembly. C.C. Brauer, A.J. Teuling, P.J.J.F. Torfs, R. Uijlenhoet (2014a): The Wageningen Lowland Runoff Simulator (WALRUS): a lumped rainfall-runoff model for catchments with shallow groundwater, Geosci. Model Dev., 7, 2313-2332. C.C. Brauer, P.J.J.F. Torfs, A.J. Teuling, R. Uijlenhoet (2014b): The Wageningen Lowland Runoff Simulator (WALRUS): application to the Hupsel Brook catchment and Cabauw polder, Hydrol. Earth Syst. Sci., 18, 4007-4028.

  19. Peat analyses in the Hudson Bay Lowlands using ground penetrating radar

    NASA Technical Reports Server (NTRS)

    Pelletier, R. E.; Davis, J. L.; Rossiter, J. R.

    1991-01-01

    The use of ground penetrating radar (GPR) as a means to determine peak thickness and estimate peat volume in the Hudson Bay Lowlands of Canada is examined. Ground-based and airborne GPR data were acquired so as to extrapolate measurements to larger scales. While the ground-based measurements did an excellent job in determining peat depth, the airborne techniques did a fair job a low altitudes and demonstrated great promise with additional system engineering changes.

  20. Severe idiopathic hypocalcemia in a juvenile western lowland gorilla, Gorilla gorilla gorilla.

    PubMed

    Chatfield, Jenifer; Stones, Greeley; Jalil, Tania

    2012-03-01

    A 6-mo-old, male western lowland gorilla (Gorilla gorilla gorilla) was evaluated because of tetany of both hands. The gorilla had alternating periods of constipation, diarrhea, and bloating since birth. A diagnosis of idiopathic hypocalcemia was based on severe hypocalcemia, a normal vitamin D level, response to oral calcium and vitamin D therapy, and eventual resolution. Idiopathic hypocalcemia, an uncommon disease in neonatal humans, should be considered in young gorillas with persistent gastrointestinal problems or acute tetany. PMID:22448527

  1. 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

  2. Indigenous utilization of termite mounds and their sustainability in a rice growing village of the central plain of Laos

    PubMed Central

    2011-01-01

    Background The objective of this study was to investigate the indigenous utilization of termite mounds and termites in a rain-fed rice growing village in the central plain of Laos, where rice production is low and varies year-to-year, and to assess the possibility of sustainable termite mound utilization in the future. This research was carried out from 2007 to 2009. Methods The termites were collected from their mounds and surrounding areas and identified. Twenty villagers were interviewed on their use of termites and their mounds in the village. Sixty-three mounds were measured to determine their dimensions in early March, early July and middle to late November, 2009. Results Eleven species of Termitidae were recorded during the survey period. It was found that the villagers use termite mounds as fertilizer for growing rice, vegetable beds and charcoal kilns. The villagers collected termites for food and as feed for breeding fish. Over the survey period, 81% of the mounds surveyed increased in volume; however, the volume was estimated to decrease by 0.114 m3 mound-1 year-1 on average due to several mounds being completely cut out. Conclusion It was concluded that current mound utilization by villagers is not sustainable. To ensure sustainable termite utilization in the future, studies should be conducted to enhance factors that promote mound restoration by termites. Furthermore, it will be necessary to improve mound conservation methods used by the villagers after changes in the soil mass of mounds in paddy fields and forests has been measured accurately. The socio-economic factors that affect mound utilization should also be studied. PMID:21849087

  3. Rice disease research in organic production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic rice production has increased significantly in the U. S. with 35,000 acres currently under production. Texas organic rice acreage has been increasing steadily over the last 10 years with acreage in 2009 reaching 16,000, accounting for approximately 10% of the total Texas rice acreage. Contro...

  4. Is ALL Rice Bran Created Equal?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumption of whole grain rice is increasing in the U.S. This increase is likely due to increased consumer awareness of the importance of whole grains in the diet. Whole grain rice is superior nutritionally compared to milled rice because, except for carbohyrates, it contains more phytochemicals an...

  5. Understanding rice heterosis using deep sequencing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heterosis is a complex biological phenomenon where the offspring show better performance compared to the inbred parents. Although rice breeders have used heterosis in hybrid rice production for nearly 40 years, the genetic and molecular mechanism underlying the heterosis in rice is still poorly und...

  6. Rice functionality, starch structure and the genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Through collaborative efforts among USDA scientists at Beaumont, Texas, we have gained in-depth knowledge of how rice functionality, i.e. the texture of the cooked rice, rice processing properties, and starch gelatinization temperature, are associated with starch-synthesis genes and starch structure...

  7. SHEATH BLIGHT RESISTANCE IN SOUTHERN RICE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheath blight is a serious fungal disease problem in southern US rice production, making it necessary for rice farmers to diligently use fungicides for its control. There are no long grain rice varieties adapted to commercial production in the southern US that have adequate resistance to sheath bli...

  8. U.S. Rice: Enhancing human health.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A vision of the U.S. rice industry is to improve human health through the development of germplasm and technologies for products that capture the unique nutritional benefits of the rice grain. This paper gives an overview of U.S. rice production and markets. New product trends and introductions in...

  9. New market opportunities for rice grains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Breeding efforts for rice have been focusing on increasing yield and improving quality (milling yield and grain quality), while maintaining cooked rice sensory properties to meet consumer preferences. These breeding targets will no doubt continue as the main foci for the rice industry. However, the ...

  10. Lowland-upland migration of sauropod dinosaurs during the Late Jurassic epoch.

    PubMed

    Fricke, Henry C; Hencecroth, Justin; Hoerner, Marie E

    2011-12-22

    Sauropod dinosaurs were the largest vertebrates ever to walk the Earth, and as mega-herbivores they were important parts of terrestrial ecosystems. In the Late Jurassic-aged Morrison depositional basin of western North America, these animals occupied lowland river-floodplain settings characterized by a seasonally dry climate. Massive herbivores with high nutritional and water needs could periodically experience nutritional and water stress under these conditions, and thus the common occurrence of sauropods in this basin has remained a paradox. Energetic arguments and mammalian analogues have been used to suggest that migration allowed sauropods access to food and water resources over a wide region or during times of drought or both, but there has been no direct support for these hypotheses. Here we compare oxygen isotope ratios (δ(18)O) of tooth-enamel carbonate from the sauropod Camarasaurus with those of ancient soil, lake and wetland (that is, 'authigenic') carbonates that formed in lowland settings. We demonstrate that certain populations of these animals did in fact undertake seasonal migrations of several hundred kilometres from lowland to upland environments. This ability to describe patterns of sauropod movement will help to elucidate the role that migration played in the ecology and evolution of gigantism of these and associated dinosaurs. PMID:22031326

  11. Impacts of Climate Change on the Collapse of Lowland Maya Civilization

    NASA Astrophysics Data System (ADS)

    Douglas, Peter M. J.; Demarest, Arthur A.; Brenner, Mark; Canuto, Marcello A.

    2016-06-01

    Paleoclimatologists have discovered abundant evidence that droughts coincided with collapse of the Lowland Classic Maya civilization, and some argue that climate change contributed to societal disintegration. Many archaeologists, however, maintain that drought cannot explain the timing or complex nature of societal changes at the end of the Classic Period, between the eighth and eleventh centuries ce. This review presents a compilation of climate proxy data indicating that droughts in the ninth to eleventh century were the most severe and frequent in Maya prehistory. Comparison with recent archaeological evidence, however, indicates an earlier beginning for complex economic and political processes that led to the disintegration of states in the southern region of the Maya lowlands that precedes major droughts. Nonetheless, drought clearly contributed to the unusual severity of the Classic Maya collapse, and helped to inhibit the type of recovery seen in earlier periods of Maya prehistory. In the drier northern Maya Lowlands, a later political collapse at ca. 1000 ce appears to be related to ongoing extreme drought. Future interdisciplinary research should use more refined climatological and archaeological data to examine the relationship between climate and social processes throughout the entirety of Maya prehistory.

  12. Seismic reflection images beneath Puget Sound, western Washington State: The Puget Lowland thrust sheet hypothesis

    USGS Publications Warehouse

    Pratt, T.L.; Johnson, S.; Potter, C.; Stephenson, W.; Finn, C.

    1997-01-01

    Seismic reflection data show that the densely populated Puget Lowland of western Washington state is underlain by subhorizontal Paleogene and Neogene sedimentary rocks deformed by west and northwest trending faults and folds. From south to north beneath the Lowland, features seen on the seismic data include: the horizontally-stratified, 3.5 km thick Tacoma sedimentary basin; the Seattle uplift with south dipping (???20??) strata on its south flank and steeply (50?? to 90??) north dipping strata and the west-trending Seattle fault on its north flank; the 7.5 km thick, northward-thinning Seattle sedimentary basin; the antiformal Kingston arch; and the northwest trending, transpressional Southern Whidbey Island fault zone (SWIF). Interpreting the uplifts as fault-bend and fault-propagation folds leads to the hypothesis that the Puget Lowland lies on a north directed thrust sheet. The base of the thrust sheet may lie at 14 to 20 km depth within or at the base of a thick block of basaltic Crescent Formation; its edges may be right-lateral strike-slip faults along the base of the Cascade Range on the east and the Olympic Mountains on the west. Our model suggests that the Seattle fault has a long-term slip rate of about 0.25 mm/year and is large enough to generate a M7.6 to 7.7 earthquake.

  13. Seasat synthetic aperture radar /SAR/ response to lowland vegetation types in eastern Maryland and Virginia

    NASA Technical Reports Server (NTRS)

    Krohn, M. D.; Milton, N. M.; Segal, D. B.

    1983-01-01

    Examination of Seasat SAR images of eastern Maryland and Virginia reveals botanical distinctions between vegetated lowland areas and adjacent upland areas. Radar returns from the lowland areas can be either brighter or darker than returns from the upland forests. Scattering models and scatterometer measurements predict an increase of 6 dB in backscatter from vegetation over standing water. This agrees with the 30-digital number (DN) increase observed in the digital Seasat data. The brightest areas in the Chickahominy, Virginia, drainage, containing P. virginica about 0.4 m high, contrast with the brightest areas in the Blackwater, Maryland, marshes, which contain mature loblolly pine in standing water. The darkest vegetated area in the Chickahominy drainage contains a forest of Nyssa aquatica (water tupelo) about 18 m high, while the darkest vegetated area in the Blackwater marshes contains the marsh plant Spartina alterniflora, 0.3 m high. The density, morphology, and relative geometry of the lowland vegetation with respect to standing water can all affect the strength of the return L band signal.

  14. Preliminary atlas of active shallow tectonic deformation in the Puget Lowland, Washington

    USGS Publications Warehouse

    Barnett, Elizabeth A.; Haugerud, Ralph A.; Sherrod, Brian L.; Weaver, Craig S.; Pratt, Thomas L.; Blakely, Richard J.

    2010-01-01

    This atlas presents an up-to-date map compilation of the geological and geophysical observations that underpin interpretations of active, surface-deforming faults in the Puget Lowland, Washington. Shallow lowland faults are mapped where observations of deformation from paleoseismic, seismic-reflection, and potential-field investigations converge. Together, results from these studies strengthen the identification and characterization of regional faults and show that as many as a dozen shallow faults have been active during the Holocene. The suite of maps presented in our atlas identifies sites that have evidence of deformation attributed to these shallow faults. For example, the paleoseismic-investigations map shows where coseismic surface rupture and deformation produced geomorphic scarps and deformed shorelines. Other maps compile results of seismic-reflection and potential-field studies that demonstrate evidence of deformation along suspected fault structures in the subsurface. Summary maps show the fault traces derived from, and draped over, the datasets presented in the preceding maps. Overall, the atlas provides map users with a visual overview of the observations and interpretations that support the existence of active, shallow faults beneath the densely populated Puget Lowland.

  15. Seismic reflection images beneath Puget Sound, western Washington State: The Puget Lowland thrust sheet hypothesis

    NASA Astrophysics Data System (ADS)

    Pratt, Thomas L.; Johnson, Samuel; Potter, Christopher; Stephenson, William; Finn, Carol

    1997-12-01

    Seismic reflection data show that the densely populated Puget Lowland of western Washington state is underlain by subhorizontal Paleogene and Neogene sedimentary rocks deformed by west and northwest trending faults and folds. From south to north beneath the Lowland, features seen on the seismic data include: the horizontally-stratified, 3.5 km thick Tacoma sedimentary basin; the Seattle uplift with south dipping (˜20°) strata on its south flank and steeply (50° to 90°) north dipping strata and the west-trending Seattle fault on its north flank; the 7.5 km thick, northward-thinning Seattle sedimentary basin; the antiformal Kingston arch; and the northwest trending, transpressional Southern Whidbey Island fault zone (SWIF). Interpreting the uplifts as fault-bend and fault-propagation folds leads to the hypothesis that the Puget Lowland lies on a north directed thrust sheet. The base of the thrust sheet may lie at 14 to 20 km depth within or at the base of a thick block of basaltic Crescent Formation; its edges may be right-lateral strike-slip faults along the base of the Cascade Range on the east and the Olympic Mountains on the west. Our model suggests that the Seattle fault has a long-term slip rate of about 0.25 mm/year and is large enough to generate a M7.6 to 7.7 earthquake.

  16. Analysis of western lowland gorilla (Gorilla gorilla gorilla) specific Alu repeats

    PubMed Central

    2013-01-01

    Background Research into great ape genomes has revealed widely divergent activity levels over time for Alu elements. However, the diversity of this mobile element family in the genome of the western lowland gorilla has previously been uncharacterized. Alu elements are primate-specific short interspersed elements that have been used as phylogenetic and population genetic markers for more than two decades. Alu elements are present at high copy number in the genomes of all primates surveyed thus far. The AluY subfamily and its derivatives have been recognized as the evolutionarily youngest Alu subfamily in the Old World primate lineage. Results Here we use a combination of computational and wet-bench laboratory methods to assess and catalog AluY subfamily activity level and composition in the western lowland gorilla genome (gorGor3.1). A total of 1,075 independent AluY insertions were identified and computationally divided into 10 subfamilies, with the largest number of gorilla-specific elements assigned to the canonical AluY subfamily. Conclusions The retrotransposition activity level appears to be significantly lower than that seen in the human and chimpanzee lineages, while higher than that seen in orangutan genomes, indicative of differential Alu amplification in the western lowland gorilla lineage as compared to other Homininae. PMID:24262036

  17. Classic Period collapse of the Central Maya Lowlands: Insights about human–environment relationships for sustainability

    PubMed Central

    Turner, B. L.; Sabloff, Jeremy A.

    2012-01-01

    The ninth century collapse and abandonment of the Central Maya Lowlands in the Yucatán peninsular region were the result of complex human–environment interactions. Large-scale Maya landscape alterations and demands placed on resources and ecosystem services generated high-stress environmental conditions that were amplified by increasing climatic aridity. Coincident with this stress, the flow of commerce shifted from land transit across the peninsula to sea-borne transit around it. These changing socioeconomic and environmental conditions generated increasing societal conflicts, diminished control by the Maya elite, and led to decisions to move elsewhere in the peninsular region rather than incur the high costs of maintaining the human–environment systems in place. After abandonment, the environment of the Central Maya Lowlands largely recovered, although altered from its state before Maya occupation; the population never recovered. This history and the spatial and temporal variability in the pattern of collapse and abandonment throughout the Maya lowlands support the case for different conditions, opportunities, and constraints in the prevailing human–environment systems and the decisions to confront them. The Maya case lends insights for the use of paleo- and historical analogs to inform contemporary global environmental change and sustainability. PMID:22912403

  18. Spectral evidence for weathered basalt as an alternative to andesite in the northern lowlands of Mars.

    PubMed

    Wyatt, Michael B; McSween, Harry Y

    2002-05-16

    Mineral abundances derived from the analysis of remotely sensed thermal emission data from Mars have been interpreted to indicate that the surface is composed of basalt (Surface Type 1) and andesite (Surface Type 2). The global distribution of these rock types is divided roughly along the planetary dichotomy which separates ancient, heavily cratered crust in the southern hemisphere (basalt) from younger lowland plains in the north (andesite). But the existence of such a large volume of andesite is difficult to reconcile with our present understanding of the geological evolution of Mars. Here we reinterpret martian surface rock lithologies using mineral abundances from previous work and new mineralogies derived from a spectral end-member set representing minerals common in unaltered and low-temperature aqueously altered basalts. Our results continue to indicate the dominance of unaltered basalt in the southern highlands, but reveal that the northern lowlands can be interpreted as weathered basalt as an alternative to andesite. The coincidence between locations of such altered basalt and a suggested northern ocean basin implies that lowland plains material may be composed of basalts weathered under submarine conditions or weathered basaltic sediments transported into this depocentre. PMID:12015596

  19. Spread of Amphibian Chytrid Fungus across Lowland Populations of Túngara Frogs in Panamá.

    PubMed

    Rodríguez-Brenes, Sofía; Rodriguez, David; Ibáñez, Roberto; Ryan, Michael J

    2016-01-01

    Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an emergent infectious disease partially responsible for worldwide amphibian population declines. The spread of Bd along highland habitats (> 500 meters above sea level, m a.s.l.) of Costa Rica and Panamá is well documented and has been linked to amphibian population collapses. In contrast, data are scarce on the prevalence and dispersal of Bd in lowland habitats where amphibians may be infected but asymptomatic. Here we describe the spread (2009 to 2014) of Bd across lowland habitats east of the Panamá Canal (< 500 m a.s.l.) with a focus on the Túngara frog (Physalaemus [Engystomops] pustulosus), one of the most common and abundant frog species in this region. Highland populations in western Panamá were already infected with Bd at the start of the study, which was consistent with previous studies indicating that Bd is enzootic in this region. In central Panamá, we collected the first positive samples in 2010, and by 2014, we detected Bd from remote sites in eastern Panamá (Darién National Park). We discuss the importance of studying Bd in lowland species, which may serve as potential reservoirs and agents of dispersal of Bd to highland species that are more susceptible to chytridiomycosis. PMID:27176629

  20. Spread of Amphibian Chytrid Fungus across Lowland Populations of Túngara Frogs in Panamá

    PubMed Central

    Rodríguez-Brenes, Sofía; Rodriguez, David; Ibáñez, Roberto; Ryan, Michael J.

    2016-01-01

    Chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an emergent infectious disease partially responsible for worldwide amphibian population declines. The spread of Bd along highland habitats (> 500 meters above sea level, m a.s.l.) of Costa Rica and Panamá is well documented and has been linked to amphibian population collapses. In contrast, data are scarce on the prevalence and dispersal of Bd in lowland habitats where amphibians may be infected but asymptomatic. Here we describe the spread (2009 to 2014) of Bd across lowland habitats east of the Panamá Canal (< 500 m a.s.l.) with a focus on the Túngara frog (Physalaemus [Engystomops] pustulosus), one of the most common and abundant frog species in this region. Highland populations in western Panamá were already infected with Bd at the start of the study, which was consistent with previous studies indicating that Bd is enzootic in this region. In central Panamá, we collected the first positive samples in 2010, and by 2014, we detected Bd from remote sites in eastern Panamá (Darién National Park). We discuss the importance of studying Bd in lowland species, which may serve as potential reservoirs and agents of dispersal of Bd to highland species that are more susceptible to chytridiomycosis. PMID:27176629

  1. Incised channel fills containing conifers indicate that seasonally dry vegetation dominated Pennsylvanian tropical lowlands

    USGS Publications Warehouse

    Falcon-Lang, H. J.; Nelson, W.J.; Elrick, S.; Looy, C.V.; Ames, P.R.; DiMichele, W.A.

    2009-01-01

    The idea that the Pennsylvanian tropical lowlands were temporally dominated by rainforest (i.e., the Coal Forest) is deeply ingrained in the literature. Here we challenge two centuries of research by suggesting that this concept is based on a taphonomic artifact, and that seasonally dry vegetation dominated instead. This controversial finding arises from the discovery of a new middle Pennsylvanian (Moscovian) fossil plant assemblage in southeast Illinois, United States. The assemblage, which contains xerophytic walchian conifers, occurs in channels incised into a calcic Vertisol below the Baker Coal. These plants grew on seasonally dry tropical lowlands inferred to have developed during a glacial phase. This xerophytic flora differs markedly from that of the typical clubmoss-dominated Coal Forest developed during deglaciation events. Although preserved only very rarely, we argue that such xerophytic floras were temporally as dominant, and perhaps more dominant, than the iconic Coal Forests, which are overrepresented in the fossil record due to taphonomic megabias. These findings require the iconography of Pennsylvanian tropical lowlands to be redrawn. ?? 2009 Geological Society of America.

  2. The Hindlimb Arterial Vessels in Lowland paca (Cuniculus paca, Linnaeus 1766).

    PubMed

    Leal, L M; de Freitas, H M G; Sasahara, T H C; Machado, M R F

    2016-04-01

    This study aims to describe the origin and distribution of the hindlimb arterial vessels. Five adult lowland pacas (Cuniculus paca) were used. Stained and diluted latex was injected, caudally to the aorta. After fixation in 10% paraformaldehyde for 72 h, we dissected to visualize and identify the vessels. It was found out that the vascularization of the hindlimb in lowland paca derives from the terminal branch of the abdominal aorta. The common iliac artery divides into external iliac and internal iliac. The external iliac artery emits the deep iliac circumflex artery, the pudendal epigastric trunk, the deep femoral artery; the femoral artery originates the saphenous artery, it bifurcates into cranial and caudal saphenous arteries. Immediately after the knee joint, the femoral artery is called popliteal artery, which divides into tibial cranial and tibial caudal arteries at the level of the crural inter-osseous space. The origin and distribution of arteries in the hindlimb of lowland paca resembles that in other wild rodents, as well as in the domestic mammals. PMID:25370292

  3. Cuticular hydrocarbons corroborate the distinction between lowland and highland Natal fruit fly (Tephritidae, Ceratitis rosa) populations

    PubMed Central

    Vaníčková, Lucie; Břízová, Radka; Pompeiano, Antonio; Ekesi, Sunday; Meyer, Marc De

    2015-01-01

    Abstract The cuticular hydrocarbons (CHs) and morphology of two Ceratitis rosa Karsch (Diptera: Tephritidae) populations, putatively belonging to two cryptic taxa, were analysed. The chemical profiles were characterised by two-dimensional gas chromatography with mass spectrometric detection. CHs of Ceratitis rosa that originated from the lowlands and highlands of Kenya comprised of n-alkanes, monomethylalkanes, dimethylalkanes and unsaturated hydrocarbons in the range of the carbon backbone from C14 to C37. Hydrocarbons containing C29, C31, C33 and C35 carbon atoms predominated in these two populations. 2-Methyltriacontane was the predominant compound in both populations. Quantitative differences in the distribution of hydrocarbons of different chain lengths, mainly the C22, C32, C33 and C34 compounds of these two populations, were observed despite indistinct qualitative differences in these hydrocarbons. Morphological analyses of male legs confirmed that the flies belong to different morphotypes of Ceratitis rosa previously labelled as R1 and R2 for lowland and highland populations, respectively. A statistical analysis of the CH compositions of the putative R1 and R2 species showed distinct interspecific identities, with several CHs specific for each of the lowland and highland populations. This study supports a hypothesis that the taxon Ceratitis rosa consists of at least two biological species. PMID:26798275

  4. Rice Root Architectural Plasticity Traits and Genetic Regions for Adaptability to Variable Cultivation and Stress Conditions1[OPEN

    PubMed Central

    Sandhu, Nitika; Raman, K. Anitha; Torres, Rolando O.; Audebert, Alain; Dardou, Audrey; Kumar, Arvind; Henry, Amelia

    2016-01-01

    Future rice (Oryza sativa) crops will likely experience a range of growth conditions, and root architectural plasticity will be an important characteristic to confer adaptability across variable environments. In this study, the relationship between root architectural plasticity and adaptability (i.e. yield stability) was evaluated in two traditional × improved rice populations (Aus 276 × MTU1010 and Kali Aus × MTU1010). Forty contrasting genotypes were grown in direct-seeded upland and transplanted lowland conditions with drought and drought + rewatered stress treatments in lysimeter and field studies and a low-phosphorus stress treatment in a Rhizoscope study. Relationships among root architectural plasticity for root dry weight, root length density, and percentage lateral roots with yield stability were identified. Selected genotypes that showed high yield stability also showed a high degree of root plasticity in response to both drought and low phosphorus. The two populations varied in the soil depth effect on root architectural plasticity traits, none of which resulted in reduced grain yield. Root architectural plasticity traits were related to 13 (Aus 276 population) and 21 (Kali Aus population) genetic loci, which were contributed by both the traditional donor parents and MTU1010. Three genomic loci were identified as hot spots with multiple root architectural plasticity traits in both populations, and one locus for both root architectural plasticity and grain yield was detected. These results suggest an important role of root architectural plasticity across future rice crop conditions and provide a starting point for marker-assisted selection for plasticity. PMID:27342311

  5. A Variable Cluster of Ethylene Response Factor–Like Genes Regulates Metabolic and Developmental Acclimation Responses to Submergence in Rice[W

    PubMed Central

    Fukao, Takeshi; Xu, Kenong; Ronald, Pamela C.; Bailey-Serres, Julia

    2006-01-01

    Submergence-1 (Sub1), a major quantitative trait locus affecting tolerance to complete submergence in lowland rice (Oryza sativa), contains two or three ethylene response factor (ERF)–like genes whose transcripts are regulated by submergence. In the submergence-intolerant japonica cultivar M202, this locus encodes two ERF genes, Sub1B and Sub1C. In the tolerant near-isogenic line containing the Sub1 locus from the indica FR13A, M202(Sub1), the locus additionally encodes the ERF gene Sub1A. During submergence, the tolerant M202(Sub1) displayed restrained leaf and internode elongation, chlorophyll degradation, and carbohydrate consumption, whereas the enzymatic activities of pyruvate decarboxylase and alcohol dehydrogenase were increased significantly compared with the intolerant M202. Transcript levels of genes associated with carbohydrate consumption, ethanolic fermentation, and cell expansion were distinctly regulated in the two lines. Sub1A and Sub1C transcript levels were shown to be upregulated by submergence and ethylene, with the Sub1C allele in M202 also upregulated by treatment with gibberellic acid (GA). These findings demonstrate that the Sub1 region haplotype determines ethylene- and GA-mediated metabolic and developmental responses to submergence through differential expression of Sub1A and Sub1C. Submergence tolerance in lowland rice is conferred by a specific allele variant of Sub1A that dampens ethylene production and GA responsiveness, causing quiescence in growth that correlates with the capacity for regrowth upon desubmergence. PMID:16816135

  6. Rice bran proteins: properties and food uses.

    PubMed

    Prakash, J

    1996-07-01

    Rice bran, a good source of protein and fat, is at present underutilized as a food material. The potential of producing rice bran at the global level is 27.3 million t. The presence of enzyme lipase in rice bran causes rapid deterioration of oil to free fatty acids and glycerol. Various stabilization techniques involving heat treatment, low-temperature storage, chemical treatment, control of relative humidity during storage, and simultaneous milling and extraction were evolved to inactivate lipase. Multiple forms of rice bran lipase have been identified. Fractional classification of proteins reveals a high percentage of albumins and globulins. Proteins can be extracted from full-fat or defatted rice bran by alkaline extraction and acid or heat precipitation. Extraction procedures influence the protein content of concentrates, which ranged from 19.4 to 76.1% in concentrates from full-fat rice bran and 17.5 to 85.0% in concentrates from defatted rice bran. The PER of rice bran ranges from 1.59 to 2.04 and that of protein concentrates from 1.99 to 2.19. Available lysine contents of protein concentrates ranged from 54 to 58.8%. The essential amino acid profiles of protein concentrates indicate that threonine and isoleucine are limiting amino acids. Various functional properties of rice bran protein concentrates have also been investigated that are known to be influenced by drying technique and stabilization treatment of rice bran. Rice bran has been used in food as full-fat rice bran, defatted rice bran, and in the form of rice bran oil and protein concentrates. Full-fat and defatted rice bran have been used in bakery products, breakfast cereals, wafers, as a protein supplement, binder ingredients for meats and sausages, and as a beverage base. Incorporation of protein concentrates have been studied in bread, beverages, confections, and weaning foods. PMID:8841730

  7. Evaluation of the degree of mycophilia-mycophobia among highland and lowland inhabitants from Chiapas, Mexico

    PubMed Central

    2013-01-01

    Background Mushrooms generate strong and contrasting feelings ranging from extreme aversion to intense liking. To categorize these attitudes, Wasson and Wasson coined the dichotomic terms “mycophilia” and “mycophobia” in 1957. In Mesoamerica these categories have been associated to ecological regions. Highland peoples are viewed as mycophiles, whereas lowland inhabitants are considered mycophobes. However, this division is based on little empirical evidence and few indicators. This study questioned whether mycophilia and mycophobia are indeed related to ecological regions through the evaluation of 19 indicators tested in the highlands and lowlands of Chiapas, Mexico. Methods The heterogeneity of attitudes toward mushrooms was explored in terms of ecological region and sociocultural variables. Information was obtained through structured interviews in 10 communities in Los Altos de Chiapas (highlands) and the Selva Lacandona (lowlands). We analyzed indicators separately through χ2 tests and multivariate techniques. The Mycophilia-Mycophobia Index was also used in the analysis. To assess which factors better explain the distribution of attitudes, we built 11 models using the Beta probability-density function and compared them with the Akaike Information Criterion. Results Most people had positive attitudes in both ecological regions. The classification and ordination analyses found two large groups comprising both highland and lowland towns. Contrary to expectation if mycophilia and mycophobia were mutually exclusive, all the fitted probability distributions were bell-shaped; indicating these attitudes behave as a continuous variable. The model best supported by data included occupation and ethnicity. Indigenous peasants had the highest degree of mycophilia. Discussion Results suggest the studied populations tend to be mycophilic and that their attitudes are not dichotomic, but rather a gradient. Most people occupied intermediate degrees of mycophilia

  8. Geologic Carbon Sequestration in a Lightly Explored Basin: the Puget-Willamette Lowland

    NASA Astrophysics Data System (ADS)

    Jackson, J. S.

    2007-12-01

    The Puget-Willamette Lowland is located between the Cascade Range and Olympic Mountains-Coast Range. Exploration for oil and gas there commenced in 1890. Over 700 wells subsequently drilled yield one commercial gas discovery. Eocene sediments deposited west of an ancestral Cascade Range include a coal-bearing sequence covering much of the Puget-Willamette Lowland. The terrestrial deposits pass into marine deposits to the west. Syn- depositional normal faulting and strike-slip faulting are evident in several sub-basins. In the southern Lowland, normal faults were modified by episodes of late Eocene and Miocene transpression, which resulted in mild inversion of older normal faults Preserved sediments indicate that local subsidence continued into Miocene- Pliocene time, and was followed in the northern Lowland by extensive Pleistocene glaciation. In the northern Lowland, Holocene faulting is recognized in outcrop and is interpreted on seismic data acquired in Puget Sound. Structures formed by early Miocene or earlier events may have trapped migrating hydrocarbons. Structures formed or modified by Holocene faulting very probably post-date hydrocarbon generation and migration. The region appears to host potential geologic sequestration targets, including coals, sandstones, and vesicular basalt flows. The size and location of potential traps is poorly constrained by present data. Experience in better explored fore arc basins suggests 10 to 30 percent of the basin may be deformed into suitable trapping geometries. Modern seismic data is required to identify potential sequestration traps. More than one well will be required to confirm the presence and size of these traps. The present boom in oil and gas drilling has created a robust environment for seismic and drilling companies, who command unprecedented rates for their services. Only one seismic crew is presently active on the West Coast, and only a few exploration drilling rigs are available. If this environment

  9. Extending a rainfall-runoff model for lowland catchments from lumped to semi-distributed

    NASA Astrophysics Data System (ADS)

    Brauer, Claudia; Torfs, Paul; Teuling, Ryan; Uijlenhoet, Remko

    2016-04-01

    The Wageningen Lowland Runoff Simulator (WALRUS) is a parametric rainfall-runoff model for catchments with shallow groundwater (Brauer et al., 2014ab). WALRUS was developed using data and experience from two Dutch experimental catchments: the Hupsel Brook catchment (6.5 km2) and the Cabauw polder (0.5 km2). We identified key processes for runoff generation in lowland catchments, notably (1) groundwater-unsaturated zone coupling, (2) wetness-dependent flow routes, (3) groundwater-surface water feedbacks and (4) seepage and surface water supply, and accounted for these in the model structure. Up to now, WALRUS has been used in a lumped manner. However, water managers and researchers have expressed an interest in a semi-distributed version for application to larger catchments with varying forcing and catchment characteristics and to investigate the effect of groundwater flow within the catchment on modelled variables (e.g. groundwater depth). We combined WALRUS and a model for 2-dimensional groundwater flow into a simple modelling framework. WALRUS was already designed to cope with groundwater flow into or out of the model domain, because seepage and lateral groundwater flow are common in lowlands. In the semi-distributed version, we used this feature to couple different WALRUS elements (grid cells or subcatchments) to each other. Groundwater flow was computed using a digital elevation model, groundwater depths computed by WALRUS, soil transmissivity data and Darcy's law. Finally, we implemented a surface routing model including backwater effects, which are relevant in areas with little relief. With respect to the lumped version, the semi-distributed requires more data. Therefore, we investigated the added value of different data sources (forcing, elevation, soil, surface water) separately. We will present the rationale behind the semi-distributed model and show how the model structure compares to observations and and simulations without lateral transport. C.C. Brauer

  10. Role of the Hudson Bay Lowland as a source of atmospheric methane

    SciTech Connect

    Roulet, N.T.; Jano, A.; Kelly, C.A.; Klinger, L.F.; Moore, T.R.; Protz, R.; Ritter, J.A.; Rouse, W.R.

    1994-01-20

    Based on point measurements of methane flux from wetlands in the boreal and subarctic regions, northern wetlands are a major source of atmospheric methane. However, measurements have not been carried out in large continuous peatlands such as the Hudson Bay Lowland (HBL) (320,000 km{sup 2}) and the Western Siberian lowland (540,000 km{sup 2}), which together account for over 30% of the wetlands north of 40{degrees}N. To determine the role the Hudson Bay Lowland as a source of atmospheric methane, fluxes were measured by enclosure throughout the 1990 snow-free period in all the major wetland types and also by an aircraft in July. Two detailed survey areas were investigated: one ({approx} 900 km{sup 2}) was in the high subarctic region of the northern lowland and the second area ({approx} 4,800 km{sup 2}) straddled the Low Subarctic and High Boreal regions of the southern lowland. On a per unit area basis, 1.31 {+-} 0.11 and 2.79 {+-} 0.39 g CH{sub 4} m{sup {minus}2} yr{sup {minus}1} were emitted from the southern and northern survey areas, respectively. The extrapolated enclosure estimates for a 3-week period in July were compared to within 10% of the flux derived by airborne eddy correlation measurements made during the same period. The aircraft mean flux of 10 {+-} 9 mg CH{sub 4} m{sup {minus}2} d{sup {minus}1} was not statistically different from the extrapolated mean flux of 20 {+-} 16 mg CH{sub 4} m{sup {minus}2} d{sup {minus}1}. The annual habitat-weighted emission for the entire HBL using six wetland classes is estimated as 0.538 {+-} 0.187 Tg CH{sub 4} yr{sup {minus}1} (range of extreme cases is 0.057 to 2.112 Tg CH{sub 4} yr{sup {minus}1}). This value is much lower than expected, based on previous emission estimates from northern wetlands. 40 refs., 6 figs., 8 tabs.

  11. Spatial and temporal variations in rainfall characteristics in mountainous and lowland areas in Taiwan

    NASA Astrophysics Data System (ADS)

    Kume, T.; Kao, S.; Komatsu, H.; Liang, W.

    2012-12-01

    Although changes in rainfall characteristics have been noted across the world, few studies have reported those in mountainous areas. This study was undertaken to clarify spatial and temporal variations in rainfall characteristics such as annual rainfall amount (Pr), mean daily rainfall intensity (η), and ratio of rain days (λ) in mountainous and lowland areas in Taiwan with the altitude of about 4000m. To this aim, we examined spatial and year-to-year variations and marginal long-term trends in Pr, η, and λ, based on rainfall data from 120 stations during the period 1978-2008. The period mean rainfall (Pr_bar) at the lowland stations had strong relationships with the period mean daily rainfall intensity (η_bar) and the period mean ratio of rain days (λ_bar) during those 31 years. Meanwhile, Pr_bar was only strongly related to η_bar at mountainous stations, indicating that influences on spatial variations in Pr_bar were different between lowland and mountainous stations. Year-to-year variations in Pr at each station were primarily determined from the variation in η at most stations, for both lowland and mountainous stations. Long-term trend analysis showed that Pr and η increased significantly at 10% and 31% of the total 120 stations, respectively, and λ decreased significantly at 6% of the total. The increases in Pr were mostly accompanied by increases in η. Although stations with significant η increases were slightly biased toward the western lowland area, increases or decreases in Pr and λ were not common. We also examined the long-term trend for Pr in spring, summer, autumn, and winter, respectively, showing the increase trends in annual Pr were probably generated by the increases in Pr during the period from summer to winter seasons. Pr in the spring showed significant decreasing trends at 8% of the total and insignificant decreasing trend at 84% of the total. These results contribute to understanding the impacts of possible climate changes on

  12. Role of the Hudson Bay lowland as a source of atmospheric methane

    NASA Technical Reports Server (NTRS)

    Roulet, Nigel T.; Jano, A.; Kelly, C. A.; Klinger, L. F.; Moore, T. R.; Protz, R.; Ritter, J. A.; Rouse, W. R.

    1994-01-01

    Based on point measurements of methane flux from wetlands in the boreal and subarctic regions, northern wetlands are a major source of atmospheric methane. However, measurements have not been carried out in large continuous peatlands such as the Hudson Bay Lowland (HBL) (320,000 sq km) and the Western Siberian lowland (540,000 sq km), which together account for over 30% of the wetlands north of 40 deg N. To determine the role the Hudson Bay Lowland as a source of atmospheric methane, fluxes were measured by enclosures throughout the 1990 snow-free period in all the major wetland types and also by an aircraft in July. Two detailed survey areas were investigated: one (approximately 900 sq km) was in the high subarctic region of the northern lowland and the second area (approximately 4,800 sq km) straddled the Low Subarctic and High Boreal regions of the southern lowland. The fluxes were integrated over the study period to produce annual methane emissions for each wetland type. The fluxes were then weighted by the area of 16 different habitats for the southern area and 5 habitats for the northern area, as determined from Landsat thematic mapper to yield an annual habitat-weighted emission. On a per unit area basis, 1.31 +/- 0.11 and 2.79 +/- 0.39 g CH4 m(exp -2)/yr were emitted from the southern and northern survey areas, respectively. The extrapolated enclosure estimates for a 3-week period in July were compared to within 10% of the flux derived by airborne eddy correlation measurements made during the same period. The aircraft mean flux of 10 +/- 9 mg CH4 m(exp -2)/d was not statistically different from the extrapolated mean flux of 20 +/- 16 mg CH4 m(exp -2)/d. The annual habitat-weighted emission for the entire HBL using six wetland classes is estimated as 0.538 +/- 0.187 Tg CH4/yr (range of extreme cases is 0.057 to 2.112 Tg CH4/yr). This value is much lower than expected, based on previous emission estimates from northern wetlands.

  13. Quantitative estimates of tropical temperature change in lowland Central America during the last 42 ka

    NASA Astrophysics Data System (ADS)

    Grauel, Anna-Lena; Hodell, David A.; Bernasconi, Stefano M.

    2016-03-01

    Determining the magnitude of tropical temperature change during the last glacial period is a fundamental problem in paleoclimate research. Large discrepancies exist in estimates of tropical cooling inferred from marine and terrestrial archives. Here we present a reconstruction of temperature for the last 42 ka from a lake sediment core from Lake Petén Itzá, Guatemala, located at 17°N in lowland Central America. We compared three independent methods of glacial temperature reconstruction: pollen-based temperature estimates, tandem measurements of δ18O in biogenic carbonate and gypsum hydration water, and clumped isotope thermometry. Pollen provides a near-continuous record of temperature change for most of the glacial period but the occurrence of a no-analog pollen assemblage during cold, dry stadials renders temperature estimates unreliable for these intervals. In contrast, the gypsum hydration and clumped isotope methods are limited mainly to the stadial periods when gypsum and biogenic carbonate co-occur. The combination of palynological and geochemical methods leads to a continuous record of tropical temperature change in lowland Central America over the last 42 ka. Furthermore, the gypsum hydration water method and clumped isotope thermometry provide independent estimates of not only temperature, but also the δ18O of lake water that is dependent on the hydrologic balance between evaporation and precipitation over the lake surface and its catchment. The results show that average glacial temperature was cooler in lowland Central America by 5-10 °C relative to the Holocene. The coldest and driest times occurred during North Atlantic stadial events, particularly Heinrich stadials (HSs), when temperature decreased by up to 6 to 10 °C relative to today. This magnitude of cooling is much greater than estimates derived from Caribbean marine records and model simulations. The extreme dry and cold conditions during HSs in the lowland Central America were associated

  14. QTLs and candidate genes for rice root growth under flooding and upland conditions.

    PubMed

    Zheng, Bing-Song; Yang, Ling; Mao, Chuan-Zao; Zhang, Wei-Ping; Wu, Ping

    2006-02-01

    To investigate the genetic factors underlying constitutive and adaptive root growth under different water-supply conditions, a double haploid (DH) population, derived from a cross between lowland rice variety IR64 and upland rice variety Azucena, with 284 molecular markers was used in cylindrical pot experiments. Several QTLs for seminal root length (SRL), adventitious root number (ARN) and total root dry weight (RW) respectively, under both flooding and upland conditions were detected. Two identical QTLs for SRL and RW were found under flooding and upland conditions. The relative parameters defined as the ratio of parameters under the two water-supply conditions were also used for QTL analysis. A comparative analysis among different genetic populations was performed for the QTLs for root traits and several consistent QTLs for root traits across genetic backgrounds were detected. Candidate genes for cell expansion and elongation were used for comparative mapping with the detected QTLs. Four cell wall-related expressed sequence tags (ESTs) for OsEXP2, OsEXP4, EXT and Xet were mapped on the intervals carrying the QTLs for root traits. PMID:16529298

  15. Association mapping for yield and grain quality traits in rice (Oryza sativa L.)

    PubMed Central

    2010-01-01

    Association analysis was applied to a panel of accessions of Embrapa Rice Core Collection (ERiCC) with 86 SSR and field data from two experiments. A clear subdivision between lowland and upland accessions was apparent, thereby indicating the presence of population structure. Thirty-two accessions with admixed ancestry were identified through structure analysis, these being discarded from association analysis, thus leaving 210 accessions subdivided into two panels. The association of yield and grain-quality traits with SSR was undertaken with a mixed linear model, with markers and subpopulation as fixed factors, and kinship matrix as a random factor. Eight markers from the two appraised panels showed significant association with four different traits, although only one (RM190) maintained the marker-trait association across years and cultivation. The significant association detected between amylose content and RM190 was in agreement with previous QTL analyses in the literature. Herein, the feasibility of undertaking association analysis in conjunction with germplasm characterization was demonstrated, even when considering low marker density. The high linkage disequilibrium expected in rice lines and cultivars facilitates the detection of marker-trait associations for implementing marker assisted selection, and the mining of alleles related to important traits in germplasm. PMID:21637426

  16. Association mapping for yield and grain quality traits in rice (Oryza sativa L.).

    PubMed

    de Oliveira Borba, Tereza Cristina; Brondani, Rosana Pereira Vianello; Breseghello, Flávio; Coelho, Alexandre Siqueira Guedes; Mendonça, João Antônio; Rangel, Paulo Hideo Nakano; Brondani, Claudio

    2010-07-01

    Association analysis was applied to a panel of accessions of Embrapa Rice Core Collection (ERiCC) with 86 SSR and field data from two experiments. A clear subdivision between lowland and upland accessions was apparent, thereby indicating the presence of population structure. Thirty-two accessions with admixed ancestry were identified through structure analysis, these being discarded from association analysis, thus leaving 210 accessions subdivided into two panels. The association of yield and grain-quality traits with SSR was undertaken with a mixed linear model, with markers and subpopulation as fixed factors, and kinship matrix as a random factor. Eight markers from the two appraised panels showed significant association with four different traits, although only one (RM190) maintained the marker-trait association across years and cultivation. The significant association detected between amylose content and RM190 was in agreement with previous QTL analyses in the literature. Herein, the feasibility of undertaking association analysis in conjunction with germplasm characterization was demonstrated, even when considering low marker density. The high linkage disequilibrium expected in rice lines and cultivars facilitates the detection of marker-trait associations for implementing marker assisted selection, and the mining of alleles related to important traits in germplasm. PMID:21637426

  17. Rice, indica (Oryza sativa L.).

    PubMed

    Hiei, Yukoh; Ishida, Yuji; Komari, Toshihiko

    2015-01-01

    Indica varieties, which are generally recalcitrant to tissue culture and transformation, occupy 80 % of rice cultivation area in the world. Therefore, transformation method for indica rice must be improved greatly so that global rice production would take full advantage of cutting-edge biotechnology. An efficient protocol for indica transformation mediated by Agrobacterium tumefaciens is hereby described. Immature embryos collected from plants in a greenhouse are cocultivated with A. tumefaciens after pretreatment with heat and centrifuging. The protocol was successfully tested in many elite indica cultivars such as IR8, IR24, IR58025B, IR64, IR72, Suweon 258, and Nanjing 11, yielding between 5 and 15 of independent transgenic plants per immature embryo. The use of immature embryos is recommended because gene transfer to them could be much more efficient and much less genotype dependent than gene transfer to callus. PMID:25300838

  18. Tillering and panicle branching genes in rice.

    PubMed

    Liang, Wei-hong; Shang, Fei; Lin, Qun-ting; Lou, Chen; Zhang, Jing

    2014-03-01

    Rice (Oryza sativa L.) is one of the most important staple food crops in the world, and rice tillering and panicle branching are important traits determining grain yield. Since the gene MONOCULM 1 (MOC 1) was first characterized as a key regulator in controlling rice tillering and branching, great progress has been achieved in identifying important genes associated with grain yield, elucidating the genetic basis of yield-related traits. Some of these important genes were shown to be applicable for molecular breeding of high-yielding rice. This review focuses on recent advances, with emphasis on rice tillering and panicle branching genes, and their regulatory networks. PMID:24345551

  19. Iron Biofortification of Myanmar Rice

    PubMed Central

    Aung, May Sann; Masuda, Hiroshi; Kobayashi, Takanori; Nakanishi, Hiromi; Yamakawa, Takashi; Nishizawa, Naoko K.

    2013-01-01

    Iron (Fe) deficiency elevates human mortality rates, especially in developing countries. In Myanmar, the prevalence of Fe-deficient anemia in children and pregnant women are 75 and 71%, respectively. Myanmar people have one of the highest per capita rice consumption rates globally. Consequently, production of Fe-biofortified rice would likely contribute to solving the Fe-deficiency problem in this human population. To produce Fe-biofortified Myanmar rice by transgenic methods, we first analyzed callus induction and regeneration efficiencies in 15 varieties that are presently popular because of their high-yields or high-qualities. Callus formation and regeneration efficiency in each variety was strongly influenced by types of culture media containing a range of 2,4-dichlorophenoxyacetic acid concentrations. The Paw San Yin variety, which has a high-Fe content in polished seeds, performed well in callus induction and regeneration trials. Thus, we transformed this variety using a gene expression cassette that enhanced Fe transport within rice plants through overexpression of the nicotianamine synthase gene HvNAS1, Fe flow to the endosperm through the Fe(II)-nicotianamine transporter gene OsYSL2, and Fe accumulation in endosperm by the Fe storage protein gene SoyferH2. A line with a transgene insertion was successfully obtained. Enhanced expressions of the introduced genes OsYSL2, HvNAS1, and SoyferH2 occurred in immature T2 seeds. The transformants accumulated 3.4-fold higher Fe concentrations, and also 1.3-fold higher zinc concentrations in T2 polished seeds compared to levels in non-transgenic rice. This Fe-biofortified rice has the potential to reduce Fe-deficiency anemia in millions of Myanmar people without changing food habits and without introducing additional costs. PMID:23750162

  20. Climate change mitigation in the agricultural sector- an analysis of marginal abatement costs of climate mitigation in global paddy rice agriculture based on DNDC simulations

    NASA Astrophysics Data System (ADS)

    Li, C.; Li, J.; Beach, R.; Salas, W.; Ingraham, P.; Ragnauth, S.

    2012-12-01

    Authors: Jia Li1, Robert H. Beach2, Changsheng Li3, William Salas4, Pete Ingraham5, Shaun Ragnauth1 INSTITUTIONS (ALL): 1. Climate Change Division, US Environmental Protection Agency, Washington, DC, United States. 2. RTI International, Durham, NC, United States. 3. ESRC, University of New Hampshire, Durham, NH, United States. 4. Applied Geosolutions, LLC, Newmarket, NH, United States. Global agriculture sector faces the dual challenge of climate change mitigation and providing food security for a growing population. In a new study, the U.S. EPA has developed an analysis of mitigation of non-CO2 greenhouse gases for the global agriculture sector. We estimate global greenhouse gas (GHG) emissions from paddy rice cultivation and rice yields under baseline management conditions as well as for alternative mitigation options. These biophysical effects are combined with data on input use and costs to estimate marginal abatement cost curves and evaluate the cost-effectiveness of mitigation options for global rice cropping systems. DNDC, a process-based crop model, is used to simulate crop yields, methane and nitrous oxide emissions, as well as soil carbon sequestration of the various rice cropping systems (irrigated and rainfed, and single, double, triple and mixed rotations) under local climatic and soil conditions at a 0.5 degree resolution at the global scale. We evaluate the impacts of various management alternatives (e.g., flooding methods, fertilizer applications, and crop residue management) on crop yields and GHG emissions and report the spatial and temporal distributions of the outcomes. The analysis provides important insights on the potential for closing the production efficiency gaps and the trade-offs and synergies between GHG mitigation and food security in different parts of the world.

  1. Incorporating rice residues into paddy soils affects methylmercury accumulation in rice.

    PubMed

    Zhu, Huike; Zhong, Huan; Wu, Jialu

    2016-06-01

    Paddy fields are characterized by frequent organic input (e.g., fertilization and rice residue amendment), which may affect mercury biogeochemistry and bioaccumulation. To explore potential effects of rice residue amendment on methylmercury (MMHg) accumulation in rice, a mercury-contaminated paddy soil was amended with rice root (RR), rice straw (RS) or composted rice straw (CS), and planted with rice. Incorporating RS or CS increased grain MMHg concentration by 14% or 11%. The observed increases could be attributed to the elevated porewater MMHg levels and thus enhanced MMHg uptake by plants, as well as increased MMHg translocation to grain within plants. Our results indicated for the first time that rice residue amendment could significantly affect MMHg accumulation in rice grain, which should be considered in risk assessment of MMHg in contaminated areas. PMID:26974480

  2. Chlorophyll fluorescence induction kinetics and yield responses in rainfed crops with variable potassium nutrition in K deficient semi-arid alfisols.

    PubMed

    Srinivasarao, Ch; Shanker, Arun K; Kundu, Sumanta; Reddy, Sharanbhoopal

    2016-07-01

    Optimum potassium (K) nutrition in semi-arid regions may help crop plants to overcome constraints in their growth and development such as moisture stress, leading to higher productivity of rainfed crops, thus judicious K management is essential. A study was conducted to evaluate the importance of K nutrition on physiological processes like photosynthesis through chlorophyll a fluorescence and chlorophyll fluorescence induction kinetics (OJIP) of rainfed crops viz., maize (Zea mays L.), pearl millet (Pennisetum glaucum), groundnut (Arachis hypogaea), sunflower (Helianthus annuus), castor (Ricinus communis L.) and cotton (Gossypium hirsutum) under water stress conditions by studying their growth attributes, water relations, yield, K uptake and use efficiency under varied K levels. Highest chlorophyll content was observed under K60 in maize and pearl millet. Narrow and wide Chl a:b ratio was observed in castor and groundnut respectively. The fluorescence yield decreased in the crops as K dosage increased, evidenced by increasing of all points (O, J, I and P) of the OJIP curves. The fluorescence transient curve for K60 was lower than K0 and K40 for all the crops. Potassium levels altered the fluorescence induction and impaired photosynthetic systems in all the crops studied. There was no distinct trend observed in leaf water potential of crops under study. Uptake of K was high in sunflower with increased rate of K application. Quantitatively, K uptake by castor crop was lesser compared to all other crops. Our results indicate that the yield reduction under low K was due to the low capacity of the crops to translocate K from non-photosynthetic organs such as stems and petioles to upper leaves and harvested organs and this in turn influenced the capacity of the crops to produce a high economic yield per unit of K taken up thus reducing utilization efficiency of K. PMID:27101276

  3. SNP-Based QTL Mapping of 15 Complex Traits in Barley under Rain-Fed and Well-Watered Conditions by a Mixed Modeling Approach

    PubMed Central

    Mora, Freddy; Quitral, Yerko A.; Matus, Ivan; Russell, Joanne; Waugh, Robbie; del Pozo, Alejandro

    2016-01-01

    This study identified single nucleotide polymorphism (SNP) markers associated with 15 complex traits in a breeding population of barley (Hordeum vulgare L.) consisting of 137 recombinant chromosome substitution lines (RCSL), evaluated under contrasting water availability conditions in the Mediterranean climatic region of central Chile. Given that markers showed a very strong segregation distortion, a quantitative trait locus/loci (QTL) mapping mixed model was used to account for the heterogeneity in genetic relatedness between genotypes. Fifty-seven QTL were detected under rain-fed conditions, which accounted for 5–22% of the phenotypic variation. In full irrigation conditions, 84 SNPs were significantly associated with the traits studied, explaining 5–35% of phenotypic variation. Most of the QTL were co-localized on chromosomes 2H and 3H. Environment-specific genomic regions were detected for 12 of the 15 traits scored. Although most QTL-trait associations were environment and trait specific, some important and stable associations were also detected. In full irrigation conditions, a relatively major genomic region was found underlying hectoliter weight (HW), on chromosome 1H, which explained between 27% (SNP 2711-234) and 35% (SNP 1923-265) of the phenotypic variation. Interestingly, the locus 1923-265 was also detected for grain yield at both environmental conditions, accounting for 9 and 18%, in the rain-fed and irrigation conditions, respectively. Analysis of QTL in this breeding population identified significant genomic regions that can be used for marker-assisted selection (MAS) of barley in areas where drought is a significant constraint. PMID:27446139

  4. SNP-Based QTL Mapping of 15 Complex Traits in Barley under Rain-Fed and Well-Watered Conditions by a Mixed Modeling Approach.

    PubMed

    Mora, Freddy; Quitral, Yerko A; Matus, Ivan; Russell, Joanne; Waugh, Robbie; Del Pozo, Alejandro

    2016-01-01

    This study identified single nucleotide polymorphism (SNP) markers associated with 15 complex traits in a breeding population of barley (Hordeum vulgare L.) consisting of 137 recombinant chromosome substitution lines (RCSL), evaluated under contrasting water availability conditions in the Mediterranean climatic region of central Chile. Given that markers showed a very strong segregation distortion, a quantitative trait locus/loci (QTL) mapping mixed model was used to account for the heterogeneity in genetic relatedness between genotypes. Fifty-seven QTL were detected under rain-fed conditions, which accounted for 5-22% of the phenotypic variation. In full irrigation conditions, 84 SNPs were significantly associated with the traits studied, explaining 5-35% of phenotypic variation. Most of the QTL were co-localized on chromosomes 2H and 3H. Environment-specific genomic regions were detected for 12 of the 15 traits scored. Although most QTL-trait associations were environment and trait specific, some important and stable associations were also detected. In full irrigation conditions, a relatively major genomic region was found underlying hectoliter weight (HW), on chromosome 1H, which explained between 27% (SNP 2711-234) and 35% (SNP 1923-265) of the phenotypic variation. Interestingly, the locus 1923-265 was also detected for grain yield at both environmental conditions, accounting for 9 and 18%, in the rain-fed and irrigation conditions, respectively. Analysis of QTL in this breeding population identified significant genomic regions that can be used for marker-assisted selection (MAS) of barley in areas where drought is a significant constraint. PMID:27446139

  5. A tillering inhibition gene influences root–shoot carbon partitioning and pattern of water use to improve wheat productivity in rainfed environments

    PubMed Central

    Hendriks, P.W.; Kirkegaard, J.A.; Lilley, J.M.; Gregory, P.J.; Rebetzke, G.J.

    2016-01-01

    Genetic modification of shoot and root morphology has potential to improve water and nutrient uptake of wheat crops in rainfed environments. Near-isogenic lines (NILs) varying for a tillering inhibition (tin) gene and representing multiple genetic backgrounds were phenotyped in contrasting, controlled environments for shoot and root growth. Leaf area, shoot and root biomass were similar until tillering, whereupon reduced tillering in tin-containing NILs produced reductions of up to 60% in total leaf area and biomass, and increases in total root length of up to 120% and root biomass to 145%. Together, the root-to-shoot ratio increased two-fold with the tin gene. The influence of tin on shoot and root growth was greatest in the cv. Banks genetic background, particularly in the biculm-selected NIL, and was typically strongest in cooler environments. A separate de-tillering study confirmed greater root-to-shoot ratios with regular tiller removal in non-tin-containing genotypes. In validating these observations in a rainfed field study, the tin allele had a negligible effect on seedling growth but was associated with significantly (P<0.05) reduced tiller number (–37%), leaf area index (–26%), and spike number (–35%) to reduce plant biomass (–19%) at anthesis. Root biomass, root-to-shoot ratio at early stem elongation, and root depth at maturity were all increased in tin-containing NILs. Soil water use was slowed in tin-containing NILs, resulting in greater water availability, greater stomatal conductance, cooler canopy temperatures, and maintenance of green leaf area during grain-filling. Together these effects contributed to increases in harvest index and grain yield. In both the controlled and field environments, the tin gene was commonly associated with increased root length and biomass, but the significant influence of genetic background and environment suggests careful assessment of tin-containing progeny in selection for genotypic increases in root growth

  6. Three-dimensional geometric morphometric analysis of talar morphology in extant gorilla taxa from highland and lowland habitats.

    PubMed

    Knigge, Ryan P; Tocheri, Matthew W; Orr, Caley M; Mcnulty, Kieran P

    2015-01-01

    Western gorillas (Gorilla gorilla) are known to climb significantly more often than eastern gorillas (Gorilla beringei), a behavioral distinction attributable to major differences in their respective habitats (i.e., highland vs. lowland). Genetic evidence suggests that the lineages leading to these taxa began diverging from one another between approximately 1 and 3 million years ago. Thus, gorillas offer a special opportunity to examine the degree to which morphology of recently diverged taxa may be "fine-tuned" to differing ecological requirements. Using three-dimensional (3D) geometric morphometrics, we compared talar morphology in a sample of 87 specimens including western (lowland), mountain (highland), and grauer gorillas (lowland and highland populations). Talar shape was captured with a series of landmarks and semilandmarks superimposed by generalized Procrustes analysis. A between-group principal components analysis of overall talar shape separates gorillas by ecological habitat and by taxon. An analysis of only the trochlea and lateral malleolar facet identifies subtle variations in trochlear shape between western lowland and lowland grauer gorillas, potentially indicative of convergent evolution of arboreal adaptations in the talus. Lastly, talar shape scales differently with centroid size for highland and lowland gorillas, suggesting that ankle morphology may track body-size mediated variation in arboreal behaviors differently depending on ecological setting. Several of the observed shape differences are linked biomechanically to the facilitation of climbing in lowland gorillas and to stability and load-bearing on terrestrial substrates in the highland taxa, providing an important comparative model for studying morphological variation in groups known only from fossils (e.g., early hominins). PMID:25338937

  7. Weedy (red) rice: An emerging constraint to global rice production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ongoing increases in the human population necessitate that rice will continue to be an essential aspect of food security for the 21st century. While production must increase in the coming decades to meet demand, such increases will be accompanied by diminished natural resources and rising productio...

  8. Insights into molecular mechanism of blast resistance in weedy rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weedy rice is a serious pest in direct-seeded rice fields in the U.S. and worldwide. Under suitable conditions, weedy rice can reduce crop yields up to 70%. However, weedy rice may carry novel disease resistance genes. Rice blast disease caused by the fungus Magnaporthe oryzae is a major disease wo...

  9. Translational genomics-rice research in agriculture research service

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although the US accounts for only approximately 1.6 % of the total world rice production, it provides about 15% of the rice in world trade, and its rice is known for its high quality. Rice is a model for genomic study of monocots and thus, numerous broad-spectrum research activities involving rice ...

  10. Rice brans, rice bran oils, and rice hulls: composition, food and industrial uses, and bioactivities in humans, animals, and cells.

    PubMed

    Friedman, Mendel

    2013-11-13

    Rice plants produce bioactive rice brans and hulls that have been reported to have numerous health-promoting effects in cells, animals, and humans. The main objective of this review is to consolidate and integrate the widely scattered information on the composition and the antioxidative, anti-inflammatory, and immunostimulating effects of rice brans from different rice cultivars, rice bran oils derived from rice brans, rice hulls, liquid rice hull smoke derived from rice hulls, and some of their bioactive compounds. As part of this effort, this paper also presents brief summaries on the preparation of health-promoting foods including bread, corn flakes, frankfurters, ice cream, noodles, pasta, tortillas, and zero-trans-fat shortening as well as industrial products such bioethanol and biodiesel fuels. Also covered are antibiotic, antiallergic, anticarcinogenic, antidiabetic, cardiovascular, allelochemical, and other beneficial effects and the mechanisms of the bioactivities. The results show that food-compatible and safe formulations with desirable nutritional and biological properties can be used to develop new multifunctional foods as well as bioethanol and biodiesel fuel. The overlapping aspects are expected to contribute to a better understanding of the potential impact of the described health-promoting potential of the rice-derived brans, oils, and hulls in food and medicine. Such an understanding will enhance nutrition and health and benefit the agricultural and industrial economies. PMID:24175575

  11. Comparison of SPI and SPEI applicability for drought impact assessment on crop production in the Danubian Lowland and the East Slovakian Lowland

    NASA Astrophysics Data System (ADS)

    Labudová, L.; Labuda, M.; Takáč, J.

    2016-07-01

    Drought belongs among the main impact factors considering crop yields. Therefore, this paper is focused on the assessment of drought occurrence and intensity as well as on its impact on crop yields on the Danubian and the East Slovakian lowlands with the spatial resolution at district level. Yield data were the main limitation of the study, which resulted in the limited length of the assessed period (1996-2013). The standardized yields of ten crops (winter wheat, spring wheat, winter barley, spring barley, rye, maize, potatoes, oilseed rape, sunflower, and sugar beet) were correlated with monthly, 2-, and 3-monthly standardized precipitation index (SPI) and standardized precipitation and evapotranspiration index (SPEI). For this purpose, the common significance level of alpha = 0.05 was used. The temporal evolution of both indices and drought occurrence during the period 1961-2013 were assessed for each district. Most crops show a higher correlation with the SPEI than with the SPI in contrast to potatoes, which reached a higher significant correlation using the SPI. The correlation also increases with increasing number of months within a time step. The highest correlation can be seen between maize and the 3-monthly SPEI in August representing summer precipitation and potential evapotranspiration conditions. Furthermore, a very high correlation was recorded considering sugar beet, which is influenced mainly by summer precipitation, because the correlation coefficient between the sugar beet and the 3-monthly SPI is as high as using the 3-monthly SPEI. Crop yields in the East Slovakian Lowland do not seem to be influenced by wet/dry periods identified using the SPI and the SPEI as their correlation with both indices is quite low and insignificant.

  12. Agriculture Education. Soybeans and Rice.

    ERIC Educational Resources Information Center

    Stuttgart Public Schools, AR.

    This curriculum guide is designed for group instruction of secondary students enrolled in one or two semester-long courses in agricultural education. The guide presents units of study in the following areas: (1) soybeans, (2) rice, and (3) orientation. Each of the 17 units of instruction follows a typical format: terminal objective, specific…

  13. Effects of Zinc Deficiency on Rice Growth and Genetic Factors Contributing to Tolerance

    PubMed Central

    Wissuwa, Matthias; Ismail, Abdelbagi M.; Yanagihara, Seiji

    2006-01-01

    Zinc (Zn) deficiency is the most widespread micronutrient disorder in rice (Oryza sativa), but efforts to develop cultivars with improved tolerance have been hampered by insufficient understanding of genetic factors contributing to tolerance. The objective of this paper was to examine alternative evaluation methods and to identify the most informative traits that would provide realistic information for rice breeders and to map quantitative trait loci (QTLs) associated with tolerance. Screening experiments in low-Zn nutrient solution and in a Zn-deficient field did not produce similar tolerance rankings in a set of segregating lines, which suggested that rhizosphere effects were of greater importance for lowland rice than internal Zn efficiency. The most severe symptom in the field was high plant mortality. The occurrence of leaf bronzing, usually regarded as indicative of susceptibility, did not necessarily concur with high plant mortality, which implied that both were under independent genetic control. The QTL mapping experiment conducted in the field with a population derived from a cross of IR74 (intolerant) with Jalmagna (tolerant) largely confirmed this. Four QTLs associated with plant mortality were detected, and only one of those colocalized with one of the four QTLs detected for leaf bronzing. The two most influential QTLs for plant mortality were detected on chromosomes 2 and 12. They explained 16.6% and 24.2% of the variation, and alleles of the tolerant donor parent Jalmagna reduced mortality by 16.6% and 14.8%, respectively. QTLs for plant mortality acted in a purely additive manner, whereas digenic epistatic interactions were important for leaf bronzing. PMID:16905666

  14. The impact of herbicide-resistant rice technology on phenotypic diversity and population structure of United States weedy rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of imazethapyr herbicide-resistant (HR) Clearfield® rice (Oryza sativa L.) to control weedy rice has increased in the past 12 years to comprise about 60% of rice acreage in Arkansas, where 43% of rice in the USA was planted in 2013. To assess the impact of HR cultivated rice on herbicide res...

  15. 14C and 13C Constraints on CO2 Cycling in Pristine and Deforested Lowland Amazonian Rivers

    NASA Astrophysics Data System (ADS)

    Mayorga, E.; Aufdenkampe, A. K.; Krusche, A. V.; Masiello, C. A.; Quay, P. D.; Richey, J. E.

    2004-12-01

    "Lowland" rivers in the Amazon are those that, unlike the Amazon mainstem, do not drain the Andean cordillera and are not directly influenced by sediments recently eroded from the Andes. The Brazilian Amazon is predominantly drained by lowland watersheds. We examined the sources and fate of CO2 and Dissolved Inorganic Carbon (DIC) in a range of small to large lowland rivers across the region. In particular, we focused on the Ji-Parana basin, which spans the deforestation arc in the state of Rondonia. Carbonate weathering appears to be a strong source of DIC in the western lowland basins (Jurua and Purus); however, carbonate-derived DIC in these systems is completely flushed out downstream through outgassing and mixing with contemporary respiratory CO2 inputs and carbonate-free tributaries. DIC exported from carbonate-free lowland soils appers to be predominantly contemporary, but some regions in the Ji-Parana headwaters export CO2 with a mean age of several decades. In that system, replacement of C3 forests with C4 pastures appears to exert a strong influence on riverine carbon cycling from small to large rivers. Inputs from riparian grasses may play a disproportionately important role. Finally, we found tentative evidence that anoxic conditions in wetlands may result in mineralization of previously protected, aged organic matter, leading to significant aging in riverine DIC.

  16. Out of Amazonia again and again: episodic crossing of the Andes promotes diversification in a lowland forest flycatcher

    PubMed Central

    Miller, Matthew J; Bermingham, Eldredge; Klicka, John; Escalante, Patricia; do Amaral, Fabio S. Raposo; Weir, Jason T; Winker, Kevin

    2008-01-01

    Most Neotropical lowland forest taxa occur exclusively on one side of the Andes despite the availability of appropriate habitat on both sides. Almost all molecular phylogenies and phylogenetic analyses of species assemblages (i.e. area cladograms) have supported the hypothesis that Andean uplift during the Late Pliocene created a vicariant barrier affecting lowland lineages in the region. However, a few widespread plant and animal species occurring in lowland forests on both sides of the Andes challenge the generality of this hypothesis. To understand the role of the Andes in the history of such organisms, we reconstructed the phylogeographic history of a widespread Neotropical flycatcher (Mionectes oleagineus) in the context of the other four species in the genus. A molecular phylogeny based on nuclear and mitochondrial sequences unambiguously showed an early basal split between montane and lowland Mionectes. The phylogeographic reconstruction of lowland taxa revealed a complex history, with multiple cases in which geographically proximate populations do not represent sister lineages. Specifically, three populations of M. oleagineus west of the Andes do not comprise a monophyletic clade; instead, each represents an independent lineage with origins east of the Andes. Divergence time estimates suggest that at least two cross-Andean dispersal events post-date Andean uplift. PMID:18285279

  17. Rice production in relation to soil quality under different rice-based cropping systems

    NASA Astrophysics Data System (ADS)

    Tran Ba, Linh; Sleutel, Steven; Nguyen Van, Qui; Thi, Guong Vo; Le Van, Khoa; Cornelis, Wim

    2016-04-01

    Soil quality of shallow paddy soils may be improved by introducing upland crops and thus a more diverse crop cultivation pattern. Yet, the causal relationship between crop performance and enhanced soil traits in rice-upland crop rotations remains elusive. The objectives of this study were to (i) find correlations among soil properties under different rice-upland crop systems and link selected soil properties to rice growth and yield, (ii) present appropriate values of soil parameters for sustainable rice productivity in heavy clay soil, (iii) evaluate the effect of rotating rice with upland crops on rice yield and economic benefit in a long-term experiment. A rice-upland crop rotational field experiment in the Vietnamese Mekong delta was conducted for 10 years using a randomized complete block design with four treatments and four replications. Treatments were: (i) rice-rice-rice (control - conventional system as farmers' practice), (ii) rice-maize-rice, (iii) rice-mung bean-rice, and (iv) rice-mung bean-maize. Soil and plant sampling were performed after harvest of the rice crop at the end of the final winter-spring cropping season (i.e. year 10). Results show differences in rice growth and yield, and economic benefit as an effect of the crop rotation system. These differences were linked with changes in bulk density, soil porosity, soil aggregate stability index, soil penetration resistance, soil macro-porosity, soil organic carbon, acid hydrolysable soil C and soil nutrient elements, especially at soil depth of 20-30 cm. This is evidenced by the strong correlation (P < 0.01) between rice plant parameters, rice yield and soil properties such as bulk density, porosity, penetration resistance, soil organic carbon and Chydrolysable. It turned out that good rice root growth and rice yield corresponded to bulk density values lower than 1.3 Mg m-3, soil porosity higher than 50%, penetration resistance below 1.0 MPa, and soil organic carbon above 25 g kg-1. The optimal

  18. Aerobic rice mechanization: techniques for crop establishment

    NASA Astrophysics Data System (ADS)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  19. Changes in lowland floodplain sedimentation processes: pre-disturbance to post-rehabilitation, Cosumnes River, CA

    NASA Astrophysics Data System (ADS)

    Florsheim, Joan L.; Mount, Jeffrey F.

    2003-12-01

    During the late Holocene, sediment deposition on the lowland Cosumnes River floodplain, CA has depended on factors that varied temporally and spatially, such as basin subsidence, sea level rise, flow, and sediment supply from both the Sacramento River system and from the Cosumnes River system itself, and anthropogenic changes. Through field investigations and analyses of historical maps, bridge core logs, and sediment size distributions, we link hydrogeomorphic processes to three stages of floodplain sedimentation on the lowland Cosumnes River. Stage I (1000-200 YBP) combined late Holocene pre-disturbance flood basin overflow and anastomosing river processes deposited spatially variable sediment consisting of gray-blue clay (87% clay) interlayered with relatively thin coarser sediment. Pre-disturbance Holocene deposition rates of up to ˜3.0 mm/year kept pace with sea level rise and tectonic basin subsidence. Stage II (200 to ˜10 YBP) anthropogenic disturbances caused a rapid increase in floodplain sedimentation rates up to 25 mm/year between 1849 and ˜1920, and deposited a relatively coarser reddish-brown sandy clay (˜40% clay) layer that overlies the basin deposits. Between ˜1920 and 1990 AD, sedimentation was greatly limited on the lower Cosumnes floodplain because levees inhibited connectivity between both the Sacramento and Cosumnes River systems and the Cosumnes floodplain. During this stage, the density of channel segments in the anastomosing river floodplain decreased by 30% as agricultural activities filled secondary channels and leveled floodplain topography. During Stage III (˜10 YBP to the present), post-rehabilitation floodplain sand splay complex sediment deposited after 1998 AD resulted from intentionally breaching levees to promote habitat at the Cosumnes River Preserve. The splay complex is dominated by medium to very coarse sand with finer intervening layers. The post-rehabilitation splay complex overlies the older basin deposits in a

  20. Origin of the HIV-1 group O epidemic in western lowland gorillas.

    PubMed

    D'arc, Mirela; Ayouba, Ahidjo; Esteban, Amandine; Learn, Gerald H; Boué, Vanina; Liegeois, Florian; Etienne, Lucie; Tagg, Nikki; Leendertz, Fabian H; Boesch, Christophe; Madinda, Nadège F; Robbins, Martha M; Gray, Maryke; Cournil, Amandine; Ooms, Marcel; Letko, Michael; Simon, Viviana A; Sharp, Paul M; Hahn, Beatrice H; Delaporte, Eric; Mpoudi Ngole, Eitel; Peeters, Martine

    2015-03-17

    HIV-1, the cause of AIDS, is composed of four phylogenetic lineages, groups M, N, O, and P, each of which resulted from an independent cross-species transmission event of simian immunodeficiency viruses (SIVs) infecting African apes. Although groups M and N have been traced to geographically distinct chimpanzee communities in southern Cameroon, the reservoirs of groups O and P remain unknown. Here, we screened fecal samples from western lowland (n = 2,611), eastern lowland (n = 103), and mountain (n = 218) gorillas for gorilla SIV (SIVgor) antibodies and nucleic acids. Despite testing wild troops throughout southern Cameroon (n = 14), northern Gabon (n = 16), the Democratic Republic of Congo (n = 2), and Uganda (n = 1), SIVgor was identified at only four sites in southern Cameroon, with prevalences ranging from 0.8-22%. Amplification of partial and full-length SIVgor sequences revealed extensive genetic diversity, but all SIVgor strains were derived from a single lineage within the chimpanzee SIV (SIVcpz) radiation. Two fully sequenced gorilla viruses from southwestern Cameroon were very closely related to, and likely represent the source population of, HIV-1 group P. Most of the genome of a third SIVgor strain, from central Cameroon, was very closely related to HIV-1 group O, again pointing to gorillas as the immediate source. Functional analyses identified the cytidine deaminase APOBEC3G as a barrier for chimpanzee-to-gorilla, but not gorilla-to-human, virus transmission. These data indicate that HIV-1 group O, which spreads epidemically in west central Africa and is estimated to have infected around 100,000 people, originated by cross-species transmission from western lowland gorillas. PMID:25733890

  1. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia

    PubMed Central

    2015-01-01

    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments. PMID:26132139

  2. Widespread Forest Vertebrate Extinctions Induced by a Mega Hydroelectric Dam in Lowland Amazonia.

    PubMed

    Benchimol, Maíra; Peres, Carlos A

    2015-01-01

    Mega hydropower projects in tropical forests pose a major emergent threat to terrestrial and freshwater biodiversity worldwide. Despite the unprecedented number of existing, under-construction and planned hydroelectric dams in lowland tropical forests, long-term effects on biodiversity have yet to be evaluated. We examine how medium and large-bodied assemblages of terrestrial and arboreal vertebrates (including 35 mammal, bird and tortoise species) responded to the drastic 26-year post-isolation history of archipelagic alteration in landscape structure and habitat quality in a major hydroelectric reservoir of Central Amazonia. The Balbina Hydroelectric Dam inundated 3,129 km2 of primary forests, simultaneously isolating 3,546 land-bridge islands. We conducted intensive biodiversity surveys at 37 of those islands and three adjacent continuous forests using a combination of four survey techniques, and detected strong forest habitat area effects in explaining patterns of vertebrate extinction. Beyond clear area effects, edge-mediated surface fire disturbance was the most important additional driver of species loss, particularly in islands smaller than 10 ha. Based on species-area models, we predict that only 0.7% of all islands now harbor a species-rich vertebrate assemblage consisting of ≥80% of all species. We highlight the colossal erosion in vertebrate diversity driven by a man-made dam and show that the biodiversity impacts of mega dams in lowland tropical forest regions have been severely overlooked. The geopolitical strategy to deploy many more large hydropower infrastructure projects in regions like lowland Amazonia should be urgently reassessed, and we strongly advise that long-term biodiversity impacts should be explicitly included in pre-approval environmental impact assessments. PMID:26132139

  3. Climate Change in Lowland Central America During the Late Deglacial and Early Holocene

    SciTech Connect

    Hillesheim, M B; Hodell, D A; Leyden, B W; Brenner, M; Curtis, J H; Anselmetti, F S; Ariztegui, D; Buck, D G; Guilderson, T P; Rosenmeier, M F; Schnurrenberger, D W

    2005-02-08

    The transition from arid glacial to moist early Holocene conditions represented a profound change in northern lowland Neotropical climate. Here we report a detailed record of changes in moisture availability during the latter part of this transition ({approx}11,250 to 7,500 cal yr BP) inferred from sediment cores retrieved in Lake Peten Itza, northern Guatemala. Pollen assemblages demonstrate that a mesic forest had been largely established by {approx}11,250 cal yr BP, but sediment properties indicate that lake level was more than 35 m below modern stage. From 11,250 to 10,350 cal yr BP, during the Preboreal period, lithologic changes in sediments from deep-water cores (>50 m below modern water level) indicate several wet-dry cycles that suggest distinct changes in effective moisture. Four dry events (designated PBE1-4) occurred at 11,200, 10,900, 10,700, and 10,400 cal yr BP and correlate with similar variability observed in the Cariaco Basin titanium record and glacial meltwater pulses into the Gulf of Mexico. After 10,350 cal yr BP, multiple sediment proxies suggest a shift to a more persistently moist early Holocene climate. Comparison of results from Lake Peten Itza with other records from the circum-Caribbean demonstrates a coherent climate response during the entire span of our record. Furthermore, lowland Neotropical climate during the late deglacial and early Holocene period appears to be tightly linked to climate change in the high-latitude North Atlantic. We speculate that the observed changes in lowland Neotropical precipitation were related to the intensity of the annual cycle and associated displacements in the mean latitudinal position of the Intertropical Convergence Zone and Azores-Bermuda high-pressure system. This mechanism operated on millennial-to-submillennial timescales and may have responded to changes in solar radiation, glacial meltwater, North Atlantic sea ice, and the Atlantic meridional overturning circulation (MOC).

  4. The Wageningen Lowland Runoff Simulator (WALRUS): application to the Hupsel Brook catchment and the Cabauw polder

    NASA Astrophysics Data System (ADS)

    Brauer, C. C.; Torfs, P. J. J. F.; Teuling, A. J.; Uijlenhoet, R.

    2014-10-01

    The Wageningen Lowland Runoff Simulator (WALRUS) is a new parametric (conceptual) rainfall-runoff model which accounts explicitly for processes that are important in lowland areas, such as groundwater-unsaturated zone coupling, wetness-dependent flowroutes, groundwater-surface water feedbacks, and seepage and surface water supply (see companion paper by Brauer et al., 2014). Lowland catchments can be divided into slightly sloping, freely draining catchments and flat polders with controlled water levels. Here, we apply WALRUS to two contrasting Dutch catchments: the Hupsel Brook catchment and the Cabauw polder. In both catchments, WALRUS performs well: Nash-Sutcliffe efficiencies obtained after calibration on 1 year of discharge observations are 0.87 for the Hupsel Brook catchment and 0.83 for the Cabauw polder, with values of 0.74 and 0.76 for validation. The model also performs well during floods and droughts and can forecast the effect of control operations. Through the dynamic division between quick and slow flowroutes controlled by a wetness index, temporal and spatial variability in groundwater depths can be accounted for, which results in adequate simulation of discharge peaks as well as low flows. The performance of WALRUS is most sensitive to the parameter controlling the wetness index and the groundwater reservoir constant, and to a lesser extent to the quickflow reservoir constant. The effects of these three parameters can be identified in the discharge time series, which indicates that the model is not overparameterised (parsimonious). Forcing uncertainty was found to have a larger effect on modelled discharge than parameter uncertainty and uncertainty in initial conditions.

  5. The Wageningen Lowland Runoff Simulator (WALRUS): application to the Hupsel Brook catchment and Cabauw polder

    NASA Astrophysics Data System (ADS)

    Brauer, C. C.; Torfs, P. J. J. F.; Teuling, A. J.; Uijlenhoet, R.

    2014-02-01

    The Wageningen Lowland Runoff Simulator (WALRUS) is a new parametric (conceptual) rainfall-runoff model which accounts explicitly for processes that are important in lowland areas, such as groundwater-unsaturated zone coupling, wetness-dependent flowroutes, groundwater-surface water feedbacks, and seepage and surface water supply (see companion paper by Brauer et al., 2014). Lowland catchments can be divided into slightly sloping, freely draining catchments and flat polders with controlled water levels. Here, we apply WALRUS to two contrasting Dutch catchments: the Hupsel Brook catchment and Cabauw polder. In both catchments, WALRUS performs well: Nash-Sutcliffe efficiencies obtained after calibration on one year of discharge observations are 0.87 for the Hupsel Brook catchment and 0.83 for the Cabauw polder, with values of 0.74 and 0.76 for validation. The model also performs well during floods and droughts and can forecast the effect of control operations. Through the dynamic division between quick and slow flowroutes controlled by a wetness index, temporal and spatial variability in groundwater depths can be accounted for, which results in adequate simulation of discharge peaks as well as low flows. The performance of WALRUS is most sensitive to the parameter controlling the wetness index and the groundwater reservoir constant, and to a lesser extent to the quickflow reservoir constant. The effects of these three parameters can be identified in the discharge time series, which indicates that the model is not overparameterised (parsimonious). Forcing uncertainty was found to have a larger effect on modelled discharge than parameter uncertainty and uncertainty in initial conditions.

  6. Fire and man - reconstructing Holocene biomass burning in the central European lowlands

    NASA Astrophysics Data System (ADS)

    Dietze, Elisabeth; Słowiński, Michał; Feurdean, Angelica; Dräger, Nadine; Obremska, Milena; Ott, Florian; Pieńczewska, Anna; Theuerkauf, Martin; Brauer, Achim

    2016-04-01

    Fire is an important earth surface process that interacts with climate and vegetation and influences global biogeochemical cycles and carbon budget. Moreover, fire is tightly connected to the evolution and distributions of human beings. Especially in the humid vegetation zones that naturally do not inflame easily, fire has been the major tool to convert forests to arable land. In the central European lowlands, naturally dominated by broad-leaved forests, palaeofires were strongly related to human impact during at least the last 6000 years. Hence, the detection of past biomass burning in the sedimentological record points to human activity. Charcoal (black carbon) is the classical and widely-used proxy to reconstruct past fire histories. Abundant sedimentary charcoal records exist around the globe, and many are included in the Global Charcoal Database (GCD, www.gpwg.org). Molecular fire markers, on the other hand, are now being developed as new proxies to detect past biomass burning. This study reviews classical and "new" fire-proxies in peat and lake sediments that allow to reconstruct the signals of human impact on a regional scale in the central European lowlands with high temporal resolution. Furthermore, the charcoal records from the GCD and other sources covering the central European lowlands and adjacent areas were integrated in a spatial synthesis to document the current state-of-knowledge on regional Holocene fire history. We show preliminary charcoal data from the annually-laminated sediments of lakes Tiefer See (northeastern Germany) and Czechowskie (northern Poland). Links to reconstructed local and European-wide vegetation successions will be provided, as in times with dry climate and the dominance of a certain fire-prone vegetation cover (e.g., Pinus spec.), wildfires might have played a further important role. However, the interpretation of charcoal records is not always straightforward. Hence, we also discuss the potentials of other palaeofire

  7. Stratigraphic Architecture of a Former Lowland Kauri Swamp in Ruakaka, North Island, New Zealand.

    NASA Astrophysics Data System (ADS)

    Velez, M.; Gontz, A. M.; Lorrey, A.

    2015-12-01

    The long-lived Kauri (Agathis australis) is an endemic conifer that presently exists within 4% of their pre-human contact range in northern New Zealand. Kauri preserve well in anoxic swamp and wetland environments in the lowlands across Northland and buried, subfossil samples of this species are commonly termed 'swamp kauri'. Subfossil kauri have been recently employed as a proxy to reconstruct past climate and establish a long dendrochronological records that have direct use for building the radiocarbon calibration curve. One component of work related to interpreting ancient kauri tree ring records is improving the understanding of the stratigraphic and geomorphic history of former lowland kauri environments to outline the role of environmental change in preserving this ancient wood resource. This study contributes to improving general understanding the subsurface stratigraphy of former lowland swamp kauri sites. A combination of ground penetrating radar, sediment cores, probing transects and trench exposures, provide details for the stratigraphic relationships for one type of swamp kauri site -relic coastal dune sequences- that will form a basis for future sediment and geochemistry work. Based on GPR and trenches, the stratigraphy includes several units -Peat, woody debris, dune sand, and coastal sand. Thickness of the peat, which usually contains the subfossil kauri, varies from thin veneers over antecedent coastal deposits 10-50cm to > 2.2m, with the thickest peat accumulation located between relic foredune ridges. Prior work at locations nearby have shown Rotoehu Tephra (>45ka) has been observed as a 40 cm thick deposit. Early sedimentary analysis suggests the Rotoehu is present at our study site, but it is possibly disseminated and bioturbation may have mixed the tephra into the underlying peat sediments. OSL samples and peat sediment samples were recovered for future chemical and chronological analysis from selected locations based on GPR and trench sections.

  8. Modelling hydrological processes and analysing water-related ecosystem services of Western Siberian lowland basins

    NASA Astrophysics Data System (ADS)

    Schmalz, Britta; Kiesel, Jens; Kruse, Marion; Pfannerstill, Matthias; Sheludkov, Artyom; Khoroshavin, Vitaliy; Veshkurseva, Tatyana; Müller, Felix; Fohrer, Nicola

    2015-04-01

    For discussing and planning sustainable land management of river basins, stakeholders need suitable information on spatio-temporal patterns of hydrological components and ecosystem services. The ecosystem services concept, i.e., services provided by ecosystems that contribute to human welfare benefits, contributes comprehensive information for sustainable river management. This study shows an approach to use ecohydrological modelling results for quantifying and assessing water-related ecosystem services in three lowland river basins in Western Siberia, a region which is of global significance in terms of carbon sequestration, agricultural production and biodiversity preservation. Using the ecohydrological model SWAT, the three basins Pyschma (16762 km²), Vagai (3348 km²) and Loktinka (373 km²) were modelled following a gradient from the landscape units taiga, pre-taiga to forest steppe. For a correct representation of the Siberian lowland hydrology, the consideration of snow melt and retention of surface runoff as well as the implementation of a second groundwater aquifer was of great importance. Good to satisfying model performances were obtained for the extreme hydrological conditions. The simulated SWAT output variables of different hydrological processes were used as indicators for the two regulating services water flow and erosion regulation. The model results were translated into a relative ecosystem service valuation scale. The resulting ecosystem service maps show different spatial and seasonal patterns. Although the high resolution modelling results are averaged out within the aggregated relative valuation scale, seasonal differences can be depicted: during snowmelt, low relevant regulation can be determined, especially for water flow regulation, but a very high relevant regulation was calculated for the vegetation period during summer and for the winter period. The SWAT model serves as a suitable quantification method for the assessment of water

  9. Origin of the HIV-1 group O epidemic in western lowland gorillas

    PubMed Central

    D’arc, Mirela; Ayouba, Ahidjo; Esteban, Amandine; Learn, Gerald H.; Boué, Vanina; Liegeois, Florian; Etienne, Lucie; Tagg, Nikki; Leendertz, Fabian H.; Boesch, Christophe; Madinda, Nadège F.; Robbins, Martha M.; Gray, Maryke; Cournil, Amandine; Ooms, Marcel; Letko, Michael; Simon, Viviana A.; Sharp, Paul M.; Hahn, Beatrice H.; Delaporte, Eric; Mpoudi Ngole, Eitel; Peeters, Martine

    2015-01-01

    HIV-1, the cause of AIDS, is composed of four phylogenetic lineages, groups M, N, O, and P, each of which resulted from an independent cross-species transmission event of simian immunodeficiency viruses (SIVs) infecting African apes. Although groups M and N have been traced to geographically distinct chimpanzee communities in southern Cameroon, the reservoirs of groups O and P remain unknown. Here, we screened fecal samples from western lowland (n = 2,611), eastern lowland (n = 103), and mountain (n = 218) gorillas for gorilla SIV (SIVgor) antibodies and nucleic acids. Despite testing wild troops throughout southern Cameroon (n = 14), northern Gabon (n = 16), the Democratic Republic of Congo (n = 2), and Uganda (n = 1), SIVgor was identified at only four sites in southern Cameroon, with prevalences ranging from 0.8–22%. Amplification of partial and full-length SIVgor sequences revealed extensive genetic diversity, but all SIVgor strains were derived from a single lineage within the chimpanzee SIV (SIVcpz) radiation. Two fully sequenced gorilla viruses from southwestern Cameroon were very closely related to, and likely represent the source population of, HIV-1 group P. Most of the genome of a third SIVgor strain, from central Cameroon, was very closely related to HIV-1 group O, again pointing to gorillas as the immediate source. Functional analyses identified the cytidine deaminase APOBEC3G as a barrier for chimpanzee-to-gorilla, but not gorilla-to-human, virus transmission. These data indicate that HIV-1 group O, which spreads epidemically in west central Africa and is estimated to have infected around 100,000 people, originated by cross-species transmission from western lowland gorillas. PMID:25733890

  10. Overland flow and sediment transport in an agricultural lowland catchments: a focus on tile drain export

    NASA Astrophysics Data System (ADS)

    Vandromme, Rosalie; Grangeon, Thomas; Cerdan, Olivier; Manière, Louis; Salvador Blanes, Sébastien; Foucher, Anthony; Chapalain, Marion; Evrard, Olivier; Le Gall, Marion

    2016-04-01

    Rural landscapes have been extensively modified by human activities in Western Europe since the beginning of the 20th century in order to intensify agricultural production. Cultivated areas often expanded at the expense of grassland and wetlands located in lowland areas (de Groot et al., 2002). Therefore, large modifications were made to the agricultural landscapes: stream redesign, land consolidation, removal of hedges, and installation of tile drainage networks to drain the hydromorphic soils. These changes modified sediment processes and resulted in large morphological alterations (e.g. channel bed incision, deposition of fine sediment, channel bank erosion). Accordingly, these alterations threaten water quality and prevent to meet the requirements of the European directives. Improving water quality requires a clear understanding of the hydrosedimentary dynamics in these lowland cultivated catchments. However, few studies were conducted in drained environments. To fill this research gap, a pilot study was started in cultivated catchment of the Loire River basin, France, where tile drain densities are very high (> 1.5 km/km²). Six hydro-sedimentary monitoring stations were installed in the Louroux catchment (24 km²). One of them was specifically dedicated to measuring water/sediment fluxes from tile drains. Water level and turbidity were continuously monitored and sediments were sampled during floods and low stage periods. Samples were measured for particle size distribution, and sediment tracing studies are currently being developed to quantify the contribution of potential sources (e.g. surface vs subsurface, lithologies) to river sediment. Hydro-sedimentary fluxes were quantified and modelled for some selected events. The catchment hydrosedimentary fluxes and their properties were shown to be impacted by tile drain sediment transport, especially regarding particle size distribution, with the dominant export of very fine particles (< 2 μm) from tile drains

  11. Stock, turnover and functions of carbon in heavily weathered soils under lowland rainforest transformation systems

    NASA Astrophysics Data System (ADS)

    Guillaume, Thomas; Kuzyakov, Yakov

    2013-04-01

    Tropical rainforest are experiencing worldwide a strong lost through deforestation and transformation into agricultural systems. Land use changes in such ecosystems leads to major modifications of soils properties and processes. One indication of it are the losses of organic carbon content (Corg); an important soil fertility parameter in heavily weathered soil. Between 1985 and 2007, Sumatra (Indonesia) has lost half of his remaining natural rainforest, which currently covers only 30% the island. The deforestation is still ongoing and the main drivers of deforestation are oil palm, rubber and timber industries. Our study aims to identify and quantify the impacts of lowland rainforest transformation systems (TS): oil palm, rubber and jungle rubber plantations on soil organic carbon (SOC) and nitrogen (SON) quality, turnover and stocks and so, on soil fertility and functions. We hypothesize that transformation of natural lowland rainforest changes not only C stock and budget throughout quantity and quality of C input, but also DOM production and water consumption by vegetation, leading to a relocation of C in the subsoil. This should be reflected in C and N content in soil profile horizons as well as their δ13C and δ15N isotopic signatures. We will evaluate also C stability through biological, thermal and chemical stability in bulk soil and aggregate fractions. The TS investigated, including lowland rainforest as reference sites, are located in Jambi Province (Sumatra). Soil has been described and sampled per horizon on 4 replicates of each TS in 2 different regions (32 sites) in Autumn 2012. As hypothesized, first results show strong effects of forest transformation on C and N content, as well as on isotopic signatures of soil. Those results will also be used further to select DOM sampling depths and adequate horizons to perform sorption and incubation experiments.

  12. Evolving hydrologic connectivity in discontinuous permafrost lowlands: what it means for lake systems

    NASA Astrophysics Data System (ADS)

    Walvoord, M. A.; Jepsen, S. M.; Rover, J.; Voss, C. I.; Briggs, M. A.

    2015-12-01

    Permafrost influence on the hydrologic connectivity of surface water bodies in high-latitude lowlands is complicated by subsurface heterogeneity and the propensity of the system to change over time. In general, permafrost limits the subsurface exchange of water, solute, and nutrients between lakes and rivers. It follows that permafrost thaw could enhance subsurface hydrologic connectivity among surface water bodies, but the impact of this process on lake distribution is not well known. Changes in the extent of lakes in interior Alaska have important ecological and societal impacts since lakes provide (1) critical habitat for migratory arctic shorebirds and waterfowl, fish, and wildlife, and (2) provisional, recreational, and cultural resources for local communities. We utilize electromagnetic imaging of the shallow subsurface and remote sensing of lake level dynamics in the Yukon Flats of interior Alaska, USA, together with water balance modeling, to gain insight into the influence of discontinuous permafrost on lowland lake systems. In the study region with relatively low precipitation, observations suggest that lakes that are hydrologically isolated during normal conditions are sustained by periodic river flooding events, including ice-jam floods that occur during river ice break-up. Climatically-influenced alterations in flooding frequency and intensity, as well as depth to permafrost, are quantitatively assessed in the context of lake maintenance. Scenario modeling is used to evaluate lake level evolution under plausible changing conditions. Model results demonstrate how permafrost degradation can reduce the dependence of typical lowland lakes on flooding events. Study results also suggest that river flooding may recharge a more spatially widespread zone of lakes and wetlands under future scenarios of permafrost table deepening and enhanced subsurface hydrologic connectivity.

  13. Tropical Strains of Ralstonia solanacearum Outcompete Race 3 Biovar 2 Strains at Lowland Tropical Temperatures

    PubMed Central

    Huerta, Alejandra I.; Milling, Annett

    2015-01-01

    Bacterial wilt, caused by members of the heterogenous Ralstonia solanacearum species complex, is an economically important vascular disease affecting many crops. Human activity has widely disseminated R. solanacearum strains, increasing their global agricultural impact. However, tropical highland race 3 biovar 2 (R3bv2) strains do not cause disease in tropical lowlands, even though they are virulent at warm temperatures. We tested the hypothesis that differences in temperature adaptation and competitive fitness explain the uneven geographic distribution of R. solanacearum strains. Using three phylogenetically and ecologically distinct strains, we measured competitive fitness at two temperatures following paired-strain inoculations of their shared host, tomato. Lowland tropical strain GMI1000 was only weakly virulent on tomato under temperate conditions (24°C for day and 19°C for night [24/19°C]), but highland tropical R3bv2 strain UW551 and U.S. warm temperate strain K60 were highly virulent at both 24/19°C and 28°C. Strain K60 was significantly more competitive than both GMI1000 and UW551 in tomato rhizospheres and stems at 28°C, and GMI1000 also outcompeted UW551 at 28°C. The results were reversed at cooler temperatures, at which highland strain UW551 generally outcompeted GMI1000 and K60 in planta. The superior competitive index of UW551 at 24/19°C suggests that adaptation to cool temperatures could explain why only R3bv2 strains threaten highland agriculture. Strains K60 and GMI1000 each produced different bacteriocins that inhibited growth of UW551 in culture. Such interstrain inhibition could explain why R3bv2 strains do not cause disease in tropical lowlands. PMID:25769835

  14. Holocene coastal and palaeoenvironmental evolution in the surroundings of the Rioni Delta (Kolkheti lowlands, W Georgia)

    NASA Astrophysics Data System (ADS)

    Laermanns, Hannes; Kelterbaum, Daniel; Elashvili, Mikheil; May, Matthias; Opitz, Stephan; Hülle, Daniela; Rölkens, Julian; Brückner, Helmut

    2016-04-01

    0.0.1 The Kolkheti (Colchis) lowlands form the central part of the extensive coastal lowlands along the Black Sea coast of Georgia. Situated between the Greater and the Lesser Caucasus, favourable climatic conditions resulted in a constant human occupation of the region during the Holocene. However, due to continuous deltaic sedimentation and progradation of the Rioni River, considerable changes of the coastal configuration and the palaeoenvironmental conditions in its hinterland are considered, which also were related to sea-level fluctuations of the Black Sea and modifications in sediment supply. Because there is a paucity of data regarding the Holocene coastal evolution of Western Georgia, this study aims to (i) determine the stratigraphy of the Kolkheti lowlands; (ii) elucidate the palaeogeographical and palaeoenvironmental changes along the Georgian Black Sea coastline; and (iii) reconstruct the (relative) sea-level (RSL) evolution in the study area, and compare these results with other regional studies. 0.0.2 Our research is based on ten sediment cores and two sediment outcrops which from the northern part of the Rioni delta area, i.e. the northern part of the Kolkheti lowlands. The sediment cores were analysed for geochemical and geophysical parameters (X-ray fluorescence spectroscopy, granulometry, loss on ignition, CN analysis) and for their microfaunal content (foraminifera, ostracoda), in order to deduce different depositional environments and their succession throughout the Holocene. The chronostratigraphy is based on 13 14C and 4 IRSL ages. Our results show that significant palaeoenvironmental changes have taken place in the surroundings of the Rioni delta during the last eight millennia. The sedimentary record indicates shallow marine conditions dominating most of the research area during the 6th millennium BC. These deposits are covered by brackish/lagoonal sediments. Lateron and floodplain-related fine-grained alluvial deposits accumulated since the

  15. Ischiopagus tripus conjoined twins in a western lowland gorilla (Gorilla gorilla).

    PubMed

    Langer, S; Jurczynski, K; Gessler, A; Kaup, F-J; Bleyer, M; Mätz-Rensing, K

    2014-05-01

    Conjoined twinning is rare in man and non-human primates. The current report describes a case of ischiopagus tripus conjoined Western Lowland gorilla (Gorilla gorilla) twins. The female twins were joined at the umbilical and pelvic region, involving the liver, xiphoid, umbilicus, body wall and skin. Computed tomography revealed two complete spines. The combined pelvic space was formed by two sacra, each connected with two iliac bones. The twins were only conjoined by a common pubis. Cause of death was attributed to cardiac and circulatory collapse resulting from a large patent foramen ovale (8 mm in diameter) of one twin and neonatal asphyxia. PMID:24529511

  16. Radar mapping, archaeology, and ancient land use in the Maya lowlands

    NASA Technical Reports Server (NTRS)

    Adams, R. E. W.; Brown, W. E., Jr.; Culbert, T. P.

    1981-01-01

    Data from the use of synthetic aperture radar in aerial survey of the southern Maya lowlands suggest the presence of very large areas drained by ancient canals for the purpose of intensive cultivation. Preliminary ground checks in several very limited areas confirm the existence of canals and raised fields. Excavations and ground surveys by several scholars provide valuable comparative information. Taken together, the new data suggest that Late Classic period Maya civilization was firmly grounded in large-scale and intensive cultivation of swampy zones.

  17. Detection and quantification of trace elements in rice and rice products using x-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Foran, Kelly A.; Fleming, David E. B.

    2015-12-01

    We used X-ray fluorescence (XRF) to examine the presence of arsenic (As) and other trace elements (manganese, iron, nickel, copper, and zinc) in rice and rice products. A portable XRF analyzer was used to test samples, and amplitudes for the analyzed elements were identified in the resulting data. The detection limit of the system was sufficiently low to detect As in some rice and rice product samples.

  18. The Wageningen Lowland Runoff Simulator (WALRUS): a lumped rainfall-runoff model for catchments with shallow groundwater

    NASA Astrophysics Data System (ADS)

    Brauer, C. C.; Teuling, A. J.; Torfs, P. J. J. F.; Uijlenhoet, R.

    2014-10-01

    We present the Wageningen Lowland Runoff Simulator (WALRUS), a novel rainfall-runoff model to fill the gap between complex, spatially distributed models which are often used in lowland catchments and simple, parametric (conceptual) models which have mostly been developed for sloping catchments. WALRUS explicitly accounts for processes that are important in lowland areas, notably (1) groundwater-unsaturated zone coupling, (2) wetness-dependent flow routes, (3) groundwater-surface water feedbacks and (4) seepage and surface water supply. WALRUS consists of a coupled groundwater-vadose zone reservoir, a quickflow reservoir and a surface water reservoir. WALRUS is suitable for operational use because it is computationally efficient and numerically stable (achieved with a flexible time step approach). In the open source model code default relations have been implemented, leaving only four parameters which require calibration. For research purposes, these defaults can easily be changed. Numerical experiments show that the implemented feedbacks have the desired effect on the system variables.

  19. The Wageningen Lowland Runoff Simulator (WALRUS): a lumped rainfall-runoff model for catchments with shallow groundwater

    NASA Astrophysics Data System (ADS)

    Brauer, C. C.; Teuling, A. J.; Torfs, P. J. J. F.; Uijlenhoet, R.

    2014-02-01

    We present the Wageningen Lowland Runoff Simulator (WALRUS), a novel rainfall-runoff model to fill the gap between complex, spatially distributed models which are often used in lowland catchments and simple, parametric (conceptual) models which have mostly been developed for mountainous catchments. WALRUS explicitly accounts for processes that are important in lowland areas, notably (1) groundwater-unsaturated zone coupling, (2) wetness-dependent flow routes, (3) groundwater-surface water feedbacks and (4) seepage and surface water supply. WALRUS consists of a coupled groundwater-vadose zone reservoir, a quickflow reservoir and a surface water reservoir. WALRUS is suitable for operational use because it is computationally efficient and numerically stable (achieved with a flexible time step approach). In the open source model code default relations have been implemented, leaving only four parameters which require calibration. For research purposes, these defaults can easily be changed. Numerical experiments show that the implemented feedbacks have the desired effect on the system variables.

  20. PIXE analyses of cesium in rice grains

    NASA Astrophysics Data System (ADS)

    Sugai, Hiroyuki; Ishii, Keizo; Matsuyama, Shigeo; Terakawa, Atsuki; Kikuchi, Yohei; Takahashi, Hiroaki; Ishizaki, Azusa; Fujishiro, Fumito; Arai, Hirotsugu; Osada, Naoyuki; Karahashi, Masahiro; Nozawa, Yuichiro; Yamauchi, Shosei; Kikuchi, Kosuke; Koshio, Shigeki; Watanabe, Koji

    2014-01-01

    The Fukushima nuclear power plant accident released vast amounts of radioactive material into the environment. For instance, 134Cs and 137Cs have half-lives of about 2 and 30 years, respectively, and emit many harmful gamma rays. In 2012, rice with radioactivity >100 Bq/kg was occasionally reported in Fukushima prefecture. To determine where and how cesium accumulates in rice, we grew rice in soil containing stable cesium and investigated the distribution of cesium in rice using particle-induced X-ray emission (PIXE). This study found that cesium is accumulated in bran and germ at high concentrations, and white rice contains 40% of the cesium found in brown rice.

  1. Ventricular structure, function, and mechanics at high altitude: chronic remodeling in Sherpa vs. short-term lowlander adaptation

    PubMed Central

    Ainslie, Philip N.; Hughes, Michael G.; Stöhr, Eric J.; Cotter, James D.; Nio, Amanda Q. X.; Shave, Rob

    2014-01-01

    Short-term, high-altitude (HA) exposure raises pulmonary artery systolic pressure (PASP) and decreases left-ventricular (LV) volumes. However, relatively little is known of the long-term cardiac consequences of prolonged exposure in Sherpa, a highly adapted HA population. To investigate short-term adaptation and potential long-term cardiac remodeling, we studied ventricular structure and function in Sherpa at 5,050 m (n = 11; 31 ± 13 yr; mass 68 ± 10 kg; height 169 ± 6 cm) and lowlanders at sea level (SL) and following 10 ± 3 days at 5,050 m (n = 9; 34 ± 7 yr; mass 82 ± 10 kg; height 177 ± 6 cm) using conventional and speckle-tracking echocardiography. At HA, PASP was higher in Sherpa and lowlanders compared with lowlanders at SL (both P < 0.05). Sherpa had smaller right-ventricular (RV) and LV stroke volumes than lowlanders at SL with lower RV systolic strain (P < 0.05) but similar LV systolic mechanics. In contrast to LV systolic mechanics, LV diastolic, untwisting velocity was significantly lower in Sherpa compared with lowlanders at both SL and HA. After partial acclimatization, lowlanders demonstrated no change in the RV end-diastolic area; however, both RV strain and LV end-diastolic volume were reduced. In conclusion, short-term hypoxia induced a reduction in RV systolic function that was also evident in Sherpa following chronic exposure. We propose that this was consequent to a persistently higher PASP. In contrast to the RV, remodeling of LV volumes and normalization of systolic mechanics indicate structural and functional adaptation to HA. However, altered LV diastolic relaxation after chronic hypoxic exposure may reflect differential remodeling of systolic and diastolic LV function. PMID:24876358

  2. Ventricular structure, function, and mechanics at high altitude: chronic remodeling in Sherpa vs. short-term lowlander adaptation.

    PubMed

    Stembridge, Mike; Ainslie, Philip N; Hughes, Michael G; Stöhr, Eric J; Cotter, James D; Nio, Amanda Q X; Shave, Rob

    2014-08-01

    Short-term, high-altitude (HA) exposure raises pulmonary artery systolic pressure (PASP) and decreases left-ventricular (LV) volumes. However, relatively little is known of the long-term cardiac consequences of prolonged exposure in Sherpa, a highly adapted HA population. To investigate short-term adaptation and potential long-term cardiac remodeling, we studied ventricular structure and function in Sherpa at 5,050 m (n = 11; 31 ± 13 yr; mass 68 ± 10 kg; height 169 ± 6 cm) and lowlanders at sea level (SL) and following 10 ± 3 days at 5,050 m (n = 9; 34 ± 7 yr; mass 82 ± 10 kg; height 177 ± 6 cm) using conventional and speckle-tracking echocardiography. At HA, PASP was higher in Sherpa and lowlanders compared with lowlanders at SL (both P < 0.05). Sherpa had smaller right-ventricular (RV) and LV stroke volumes than lowlanders at SL with lower RV systolic strain (P < 0.05) but similar LV systolic mechanics. In contrast to LV systolic mechanics, LV diastolic, untwisting velocity was significantly lower in Sherpa compared with lowlanders at both SL and HA. After partial acclimatization, lowlanders demonstrated no change in the RV end-diastolic area; however, both RV strain and LV end-diastolic volume were reduced. In conclusion, short-term hypoxia induced a reduction in RV systolic function that was also evident in Sherpa following chronic exposure. We propose that this was consequent to a persistently higher PASP. In contrast to the RV, remodeling of LV volumes and normalization of systolic mechanics indicate structural and functional adaptation to HA. However, altered LV diastolic relaxation after chronic hypoxic exposure may reflect differential remodeling of systolic and diastolic LV function. PMID:24876358

  3. Left ventricular adaptation to high altitude: speckle tracking echocardiography in lowlanders, healthy highlanders and highlanders with chronic mountain sickness.

    PubMed

    Dedobbeleer, Chantal; Hadefi, Alia; Pichon, Aurelien; Villafuerte, Francisco; Naeije, Robert; Unger, Philippe

    2015-04-01

    Hypoxic exposure depresses myocardial contractility in vitro, but has been associated with indices of increased cardiac performance in intact animals and in humans, possibly related to sympathetic nervous system activation. We explored left ventricular (LV) function using speckle tracking echocardiography and sympathetic tone by spectral analysis of heart rate variability (HRV) in recently acclimatized lowlanders versus adapted or maladapted highlanders at high altitude. Twenty-six recently acclimatized lowlanders, 14 healthy highlanders and 12 highlanders with chronic mountain sickness (CMS) were studied. Control measurements at sea level were also obtained in the lowlanders. Altitude exposure in the lowlanders was associated with slightly increased blood pressure, decreased LV volumes and decreased longitudinal strain with a trend to increased prevalence of post-systolic shortening (p = 0.06), whereas the low frequency/high frequency (LF/HF) ratio increased (1.62 ± 0.81 vs. 5.08 ± 4.13, p < 0.05) indicating sympathetic activation. Highlanders had a similarly raised LF/HF ratio, but no alteration in LV deformation. Highlanders with CMS had no change in LV deformation, no significant increase in LF/HF, but decreased global HRV still suggestive of increased sympathetic tone, and lower mitral E/A ratio compared to healthy highlanders. Short-term altitude exposure in lowlanders alters indices of LV systolic function and increases sympathetic nervous system tone. Life-long altitude exposure in highlanders is associated with similar sympathetic hyperactivity, but preserved parameters of LV function, whereas diastolic function may be altered in those with CMS. Altered LV systolic function in recently acclimatized lowlanders may be explained by combined effects of hypoxia and changes in loading conditions. PMID:25665685

  4. Gene transfer rate from CL rice to diverse red rice biotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The future and sustainability of ClearfieldTM (CL) technology at the producers’ level will be dictated by various factors. Among many, prominent factors which affect the transfer of ALS-resistant gene from CL rice to red rice are: disparity in red rice biotypes and CL cultivars; flowering time of re...

  5. Screening and association mapping of rice blast disease resistance using a diverse collection of rice germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast, caused by the fungus Magnaporthe oryzae B. Couch, is a very serious disease in rice (Oryza sativa L.) worldwide. Incorporation of new blast resistance genes into breeding lines is an important objective of many rice breeding programs. A diverse collection of 409 O. sativa accessions des...

  6. Influence of Water to Rice Ratio on Cooked Rice Flavor and Texture.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water to rice ratio is known to affect cooked rice texture, whereas, the effects on flavor are largely unknown. To determine the impact of the amount of water during cooking on flavor and texture descriptive attributes, three- water to rice ratios consisting of low (less than ideal), medium (ideal)...

  7. Characterizing irrigation water requirements for rice production from the Arkansas Rice Research Verification Program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigated rice irrigation water use in the University of Arkansas Rice Research Verification Program between the years of 2003 and 2011. Irrigation water use averaged 747 mm (29.4 inches) over the nine years. A significant 40% water savings was reported for rice grown under a zero gr...

  8. Factors affecting the outcrossing rate between Clearfield rice and red rice (Oryza sativa)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The commercialization of imazethapyr-resistant (Clearfield[TM], CL) rice in the southern United States has raised serious concerns about gene flow to red rice, producing imazethapyr-resistant red rice populations. Our objectives were to determine the impact of planting date, CL cultivars, and red ri...

  9. Relative competitive ability of rice with strawhull and blackhull red rice biotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed interference depends largely upon the species composition of the weed community and an ability to compete with the cultured crop. Weedy red rice is a major weed pest of rice in the southern U.S. The focus of this study was to evaluate the competitive ability of rice against common, genetically ...

  10. Geology of the Terra Cimmeria-Utopia Planitia Highland Lowland Transitional Zone: Final Technical Approach and Scientific Results

    NASA Technical Reports Server (NTRS)

    Skinner, J. A., Jr.; Tanaka, K. L.

    2010-01-01

    The southern Utopia highland-lowland transitional zone extends from northern Terra Cimmeria to southern Utopia Planitia and contains broad, bench-like platforms with depressions, pitted cones, tholi, and lobate flows. The locally occurring geologic units and landforms contrast other transitional regions and record a spatially partitioned geologic history. We systematically delineated and described the geologic units and landforms of the southern Utopia-Cimmeria highland-lowland transitional zone for the production of a 1:1,000,000-scale geologic map (MTMs 10237, 15237, 20237, 10242, 15242, 20242, 10247, 15247, and 20247). Herein, we present technical and scientific results of this mapping project.

  11. Erosion rates and landscape evolution of the lowlands of the Upper Paraguay river basin (Brazil) from cosmogenic 10Be

    NASA Astrophysics Data System (ADS)

    Pupim, Fabiano do Nascimento; Bierman, Paul R.; Assine, Mario Luis; Rood, Dylan H.; Silva, Aguinaldo; Merino, Eder Renato

    2015-04-01

    The importance of Earth's low sloping areas in regard to global erosion and sediment fluxes has been widely and vigorously debated. It is a crucial area of research to elucidate geologically meaningful rates of land-surface change and thus the speed of element cycling on Earth. However, there are large portions of Earth where erosion rates have not been well or extensively measured, for example, the tropical lowlands. The Cuiabana lowlands are an extensive low-altitude and low-relief dissected metamorphic terrain situated in the Upper Paraguay river basin, central-west Brazil. Besides exposures of highly variable dissected metamorphic rocks, flat residual lateritic caps related to a Late Cenozoic planation surface dominate interfluves of the Cuiabana lowlands. The timescale over which the lowlands evolved and the planation surface developed, and the rate at which they have been modified by erosion, are poorly known. Here, we present measurements of in situ produced cosmogenic 10Be in outcropping metamorphic bedrock and clastic-lateritic caps to quantify rates of erosion of the surface and associated landforms in order to better understand the Quaternary landscape evolution of these lowlands. Overall, slow erosion rates (mean 10 m/Ma) suggest a stable tectonic environment in these lowlands. Erosion rates vary widely between different lithologies (range 0.57 to 28.3 m/Ma) consistent with differential erosion driving regional landform evolution. The lowest erosion rates are associated with the low-relief area (irregular plains), where clastic-laterite (mean 0.67 m/Ma) and quartzite (mean 2.6 m/Ma) crop out, whereas the highest erosion rates are associated with dissection of residual hills, dominated by metasandstone (mean 11.6 m/Ma) and phyllite (mean 27.6 m/Ma). These data imply that the Cuiabana lowland is comprised of two dominant landform sets with distinct and different dynamics. Because the planation surface (mostly lowlands) is lowering and losing mass more

  12. Wheat products as acceptable substitutes for rice.

    PubMed

    Yu, B H; Kies, C

    1993-07-01

    The objective of the study was to compare the acceptability to semi-trained US American and Asian palatability panelist, of four wheat products processed to be possible replacers of rice in human diets. Products evaluated using rice as the control standard of excellence were steamed whole wheat, couscous (steamed, extracted wheat flour semolina), rosamarina (rice shaped, extracted wheat flour pasta), and bulgar (steamed, pre-cooked partly debranned, cracked wheat). Using a ten point hedonic rating scale, both groups of panelists gave rosamarina closely followed by couscous, most favorable ratings although these ratings were somewhat lower than that of the positive control, steamed polished rice. Bulgar wheat was given the lowest evaluation and was, in general, found to be an unacceptable replacement for rice by both American and Asian judges because of its dark, 'greasy' color and distinctive flavor. In their personal dietaries, judges included rice from 0.25 to 18 times per week with the Asian judges consuming rice significantly more times per week than did the American judges (10.8 +/- 4.71 vs 1.75 +/- 1.65, p < 0.01). However, rice consumption patterns, nationality, race, or sex of the judges was not demonstrated to affect scoring of the wheat products as rice replacers. PMID:8332588

  13. Bioethanol production from rice straw residues.

    PubMed

    Belal, Elsayed B

    2013-01-01

    A rice straw - cellulose utilizing mold was isolated from rotted rice straw residues. The efficient rice straw degrading microorganism was identified as Trichoderma reesei. The results showed that different carbon sources in liquid culture such as rice straw, carboxymethyl cellulose, filter paper, sugar cane bagasse, cotton stalk and banana stalk induced T. reesei cellulase production whereas glucose or Potato Dextrose repressed the synthesis of cellulase. T. reesei cellulase was produced by the solid state culture on rice straw medium. The optimal pH and temperature for T. reesei cellulase production were 6 and 25 °C, respectively. Rice straw exhibited different susceptibilities towards cellulase to their conversion to reducing sugars. The present study showed also that, the general trend of rice straw bioconversion with cellulase was more than the general trend by T. reesei. This enzyme effectively led to enzymatic conversion of acid, alkali and ultrasonic pretreated cellulose from rice straw into glucose, followed by fermentation into ethanol. The combined method of acid pretreatment with ultrasound and subsequent enzyme treatment resulted the highest conversion of lignocellulose in rice straw to sugar and consequently, highest ethanol concentration after 7 days fermentation with S. cerevisae yeast. The ethanol yield in this study was about 10 and 11 g.L(-1). PMID:24159309

  14. Bioethanol production from rice straw residues

    PubMed Central

    Belal, Elsayed B.

    2013-01-01

    A rice straw - cellulose utilizing mold was isolated from rotted rice straw residues. The efficient rice straw degrading microorganism was identified as Trichoderma reesei. The results showed that different carbon sources in liquid culture such as rice straw, carboxymethyl cellulose, filter paper, sugar cane bagasse, cotton stalk and banana stalk induced T. reesei cellulase production whereas glucose or Potato Dextrose repressed the synthesis of cellulase. T. reesei cellulase was produced by the solid state culture on rice straw medium. The optimal pH and temperature for T. reesei cellulase production were 6 and 25 °C, respectively. Rice straw exhibited different susceptibilities towards cellulase to their conversion to reducing sugars. The present study showed also that, the general trend of rice straw bioconversion with cellulase was more than the general trend by T. reesei. This enzyme effectively led to enzymatic conversion of acid, alkali and ultrasonic pretreated cellulose from rice straw into glucose, followed by fermentation into ethanol. The combined method of acid pretreatment with ultrasound and subsequent enzyme treatment resulted the highest conversion of lignocellulose in rice straw to sugar and consequently, highest ethanol concentration after 7 days fermentation with S. cerevisae yeast. The ethanol yield in this study was about 10 and 11 g.L−1. PMID:24159309

  15. Information Commons for Rice (IC4R).

    PubMed

    Hao, Lili; Zhang, Huiyong; Zhang, Zhang; Hu, Songnian; Xue, Yu

    2016-01-01

    Rice is the most important staple food for a large part of the world's human population and also a key model organism for plant research. Here, we present Information Commons for Rice (IC4R; http://ic4r.org), a rice knowledgebase featuring adoption of an extensible and sustainable architecture that integrates multiple omics data through community-contributed modules. Each module is developed and maintained by different committed groups, deals with data collection, processing and visualization, and delivers data on-demand via web services. In the current version, IC4R incorporates a variety of rice data through multiple committed modules, including genome-wide expression profiles derived entirely from RNA-Seq data, resequencing-based genomic variations obtained from re-sequencing data of thousands of rice varieties, plant homologous genes covering multiple diverse plant species, post-translational modifications, rice-related literatures and gene annotations contributed by the rice research community. Unlike extant related databases, IC4R is designed for scalability and sustainability and thus also features collaborative integration of rice data and low costs for database update and maintenance. Future directions of IC4R include incorporation of other omics data and association of multiple omics data with agronomically important traits, dedicating to build IC4R into a valuable knowledgebase for both basic and translational researches in rice. PMID:26519466

  16. Information Commons for Rice (IC4R)

    PubMed Central

    2016-01-01

    Rice is the most important staple food for a large part of the world's human population and also a key model organism for plant research. Here, we present Information Commons for Rice (IC4R; http://ic4r.org), a rice knowledgebase featuring adoption of an extensible and sustainable architecture that integrates multiple omics data through community-contributed modules. Each module is developed and maintained by different committed groups, deals with data collection, processing and visualization, and delivers data on-demand via web services. In the current version, IC4R incorporates a variety of rice data through multiple committed modules, including genome-wide expression profiles derived entirely from RNA-Seq data, resequencing-based genomic variations obtained from re-sequencing data of thousands of rice varieties, plant homologous genes covering multiple diverse plant species, post-translational modifications, rice-related literatures and gene annotations contributed by the rice research community. Unlike extant related databases, IC4R is designed for scalability and sustainability and thus also features collaborative integration of rice data and low costs for database update and maintenance. Future directions of IC4R include incorporation of other omics data and association of multiple omics data with agronomically important traits, dedicating to build IC4R into a valuable knowledgebase for both basic and translational researches in rice. PMID:26519466

  17. Respiratory health of California rice farmers.

    PubMed

    McCurdy, S A; Ferguson, T J; Goldsmith, D F; Parker, J E; Schenker, M B

    1996-05-01

    Rice farmers are occupationally exposed to agents that may affect respiratory health, including inorganic dusts and smoke from burning of agricultural waste. To assess respiratory health of this occupational group, we conducted a cross-sectional study, including a self-administered health and work questionnaire, spirometry, and chest radiography among 464 male California rice farmers. Mean age +/- SD was 48.3 +/- 15.2 yr; mean duration of rice farming was 25.7 +/- 14.3 yr. Prevalences for respiratory symptoms were: chronic bronchitis (6.3%), physician-diagnosed asthma (7.1%), and persistent wheeze (8.8%). Chronic cough was reported by 7.1% of respondents and was associated with reported hours per year burning rice stubble. Mean FEV1 and FVC were at expected values. FEV1 was inversely associated with years working in rice storage and use of heated rice dryers. Mean FEF25-75 was 93% of expected and was inversely associated with rice storage activities involving unheated rice driers. ILO profusion scores > or = 1/0 for small irregular opacities were seen in 18 (10.1%) of 178 chest radiographs. Study findings suggest increased asthma prevalence among California rice farmers. Radiologic findings consistent with dust or fiber exposure were increased compared with those of the general population, although no associations with specific farming activities were identified. PMID:8630601

  18. Contributions of phenotypic plasticity to differences in thermogenic performance between highland and lowland deer mice.

    PubMed

    Cheviron, Zachary A; Bachman, Gwendolyn C; Storz, Jay F

    2013-04-01

    Small mammals face especially severe thermoregulatory challenges at high altitude because the reduced O2 availability constrains the capacity for aerobic thermogenesis. Adaptive enhancement of thermogenic performance under hypoxic conditions may be achieved via physiological adjustments that occur within the lifetime of individuals (phenotypic plasticity) and/or genetically based changes that occur across generations, but their relative contributions to performance differences between highland and lowland natives are unclear. Here, we examined potentially evolved differences in thermogenic performance between populations of deer mice (Peromyscus maniculatus) that are native to different altitudes. The purpose of the study was to assess the contribution of phenotypic plasticity to population differences in thermogenic performance under hypoxia. We used a common-garden deacclimation experiment to demonstrate that highland deer mice have enhanced thermogenic capacities under hypoxia, and that performance differences between highland and lowland mice persist when individuals are born and reared under common-garden conditions, suggesting that differences in thermogenic capacity have a genetic basis. Conversely, population differences in thermogenic endurance appear to be entirely attributable to physiological plasticity during adulthood. These combined results reveal distinct sources of phenotypic plasticity for different aspects of thermogenic performance, and suggest that thermogenic capacity and endurance may have different mechanistic underpinnings. PMID:23197099

  19. Salinization processes in an alluvial coastal lowland plain and effect of sea water level rise

    NASA Astrophysics Data System (ADS)

    Don, Nguyen Cao; Hang, Nguyen Thi Minh; Araki, Hiroyuki; Yamanishi, Hiroyuki; Koga, Kenichi

    2006-03-01

    In coastal areas, groundwater and aquifer systems are easily prone to pollution and contamination. Moreover, sea level rises also threaten the viability of many coastal zones and small islands. In the Shiroishi lowland plain, southwestern Kyushu Island of Japan, some environmental problems such as land subsidence and salinity intrusion due to over pumping of groundwater have long been recognized as water problems and become causes for public concern. In this study, an integrated surface and groundwater model was established and applied to the Shiroishi site to simulate groundwater flow hydraulics and predict the salinity intrusion process in the alluvial lowland plain. The simulated results show that groundwater levels in the aquifer greatly vary in response to varying climatic and pumping conditions. It is also found that sea water intrusion would be expected along the coast if the current rates of groundwater exploitation continue. Furthermore, sea water intrusion with a relative rise in sea water level due to aquifer compression and global climatic change was also considered. As a result, sea water intrusion appears to extend much farther in land from the coast compared to a reference case. The study also suggests a possible alternative to mitigate the inverse effects by pumping groundwater.

  20. Paleovegetation Simulations of Lowland Amazonia and Implications for Neotropical Allopatry and Speciation

    NASA Astrophysics Data System (ADS)

    Cowling, Sharon A.; Maslin, Mark A.; Sykes, Martin T.

    2001-03-01

    Paleovegetation modeling simulations of the lowland Amazon basin were made to assess the relative importance of glacial climate and atmospheric CO2 for altering vegetation type and structure, as well as to explore the potential physiological mechanisms underlying these ecosystem-level responses. Modeling results support the view that widespread invasion of grasslands into the Amazon lowlands during the last glaciation was not likely. Glacial cooling was probably responsible for maintaining glacial forest cover via its effects in reducing photorespiration and decreasing evapotranspiration, which collectively improve plant carbon and water relations. Modeling results confirm that leaf area index (LAI), a common proxy for canopy density, is highly sensitive to independent and interactive changes in climate and low concentration of atmospheric CO2, and the results show considerable region-to-region variation during the last glaciation. Heterogeneous variations in glacial vegetation LAI may have promoted allopatric speciation by geographically isolating species (called vicariance) in the forest (sub)canopy. The proposed vicariance hypothesis incorporating spatial variations in canopy density conforms to many of the essential tenets addressed by previous neotropical speciation models, but also helps to overcome some of their inconsistencies.

  1. Macrophytes, epipelic biofilm, and invertebrates as biotic indicators of physical habitat degradation of lowland streams (Argentina).

    PubMed

    Cortelezzi, Agustina; Sierra, María Victoria; Gómez, Nora; Marinelli, Claudia; Rodrigues Capítulo, Alberto

    2013-07-01

    Our objective was to assess the effect of the physical habitat degradation in three lowland streams of Argentina that are subject to different land uses. To address this matter, we looked into some physical habitat alterations, mainly the water quality and channel changes, the impact on macrophytes' community, and the structural and functional descriptors of the epipelic biofilm and invertebrate assemblages. As a consequence of physical and chemical perturbations, we differentiated sampling sites with different degradation levels. The low degraded sites were affected mainly for the suburban land use, the moderately degraded sites for the rural land use, and the highly degraded sites for the urban land use. The data shows that the biotic descriptors that best reflected the environmental degradation were vegetation cover and macrophytes richness, the dominance of tolerant species (epipelic biofilm and invertebrates), algal biomass, O2 consumption by the epipelic biofilm, and invertebrates' richness and diversity. Furthermore, the results obtained highlight the importance of the macrophytes in the lowland streams, where there is a poor diversification of abiotic substrates and where the macrophytes not only provide shelter but also a food source for invertebrates and other trophic levels such as fish. We also noted that both in benthic communities, invertebrates and epipelic biofilm supplied different information: the habitat's physical structure provided by the macrophytes influenced mainly the invertebrate descriptors; meanwhile, the water quality mainly influenced most of the epipelic biofilm descriptors. PMID:23149840

  2. Tropical Rain Forest and Climate Dynamics of the Atlantic Lowland, Southern Brazil, during the Late Quaternary

    NASA Astrophysics Data System (ADS)

    Behling, Hermann; Negrelle, Raquel R. B.

    2001-11-01

    Palynological analysis of a core from the Atlantic rain forest region in Brazil provides unprecedented insight into late Quaternary vegetational and climate dynamics within this southern tropical lowland. The 576-cm-long sediment core is from a former beach-ridge "valley," located 3 km inland from the Atlantic Ocean. Radio-carbon dates suggest that sediment deposition began prior to 35,000 14C yr B.P. Between ca. 37,500 and ca. 27,500 14C yr B.P. and during the last glacial maximum (LGM; ca. 27,500 to ca. 14,500 14C yr B.P.), the coastal rain forest was replaced by grassland and patches of cold-adapted forest. Tropical trees, such as Alchornea, Moraceae/Urticaceae, and Arecaceae, were almost completely absent during the LGM. Furthermore, their distributions were shifted at least 750 km further north, suggesting a cooling between 3°C and 7°C and a strengthening of Antarctic cold fronts during full-glacial times. A depauperate tropical rain forest developed as part of a successional sequence after ca. 12,300 14C yr B.P. There is no evidence that Araucaria trees occurred in the Atlantic lowland during glacial times. The rain forest was disturbed by marine incursions during the early Holocene period until ca. 6100 14C yr B.P., as indicated by the presence of microforaminifera. A closed Atlantic rain forest then developed at the study site.

  3. Comparative assessment of lowland and highland Smallholder farmers' vulnerability to climate variability in Ethiopia

    NASA Astrophysics Data System (ADS)

    Ayal, D. Y., Sr.; Abshare, M. W. M.; Desta, S. D.; Filho, W. L.

    2015-12-01

    Desalegn Yayeh Ayal P.O.BOX 150129 Addis Ababa University Ethiopia Mobil +251910824784 Abstract Smallholder farmers' near term scenario (2010-2039) vulnerability nature and magnitude was examined using twenty-two exposure, sensitivity and adaptive capacity vulnerability indicators. Assessment of smallholder farmers' vulnerability to climate variability revealed the importance of comprehending exposure, sensitivity and adaptive capacity induces. Due to differences in level of change in rainfall, temperature, drought frequency, their environmental interaction and variations on adaptive capacity the nature and magnitude of smallholder farmers vulnerability to physical, biological and epidemiological challenges of crop and livestock production varied within and across agro-ecologies. Highlanders' sensitive relates with high population density, erosion and crop disease and pest damage occurrence. Whereas lowlanders will be more sensitive to high crop disease and pest damage, provenance of livestock disease, absence of alternative water sources, less diversified agricultural practices. However, with little variations in the magnitude and nature of vulnerability, both highlanders and lowlanders are victims of climate variability and change. Given the ever increasing population, temperature and unpredictable nature of rainfall variability, the study concluded that future adaptation strategies should capitalize on preparing smallholder farmers for both extremes- excess rainfall and flooding on the one hand and severe drought on the other.

  4. Highland-lowland contrasts in the impact of Old World diseases in early colonial Ecuador.

    PubMed

    Newson, L A

    1993-05-01

    Old World epidemics played a major role in the demographic collapse of native peoples after 1492. In estimating aboriginal populations it is often assumed that once introduced Old World diseases spread unhindered and their impact was uniform. This paper indicates that there were often marked regional differences in impact of Old World diseases which were related not only to environmental conditions, but also to the size and character of native societies. Drawing on research on the demographic history of early colonial Ecuador, it demonstrates that there were marked regional differences in levels of depopulation, particularly between the highlands and lowlands. It argues that the presence of tropical fevers provides an inadequate explanation for the higher levels of depopulation in the lowlands and goes on to suggest that regional differences in the impact of Old World diseases were influenced by the size of Indian populations, their settlement patterns, forms of subsistence, social organization and ideology. These affected not only disease mortality, but also the ability of native groups to recover. PMID:8511648

  5. Finding concealed active faults: Extending the southern Whidbey Island fault across the Puget Lowland, Washington

    NASA Astrophysics Data System (ADS)

    Sherrod, Brian L.; Blakely, Richard J.; Weaver, Craig S.; Kelsey, Harvey M.; Barnett, Elizabeth; Liberty, Lee; Meagher, Karen L.; Pape, Kristin

    2008-05-01

    The southern Whidbey Island fault zone (SWIF), as previously mapped using borehole data, potential field anomalies, and marine seismic reflection surveys, consists of three subparallel, northwest trending strands extending ˜100 km from near Vancouver Island to the northern Puget Lowland. East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is concealed beneath a thick mantle of young glacial deposits and vegetation. A ˜20-km-wide, northwest trending swath of subparallel, low-amplitude aeromagnetic anomalies crosses this region of the Puget Lowland and is on strike with the SWIF. The most prominent aeromagnetic anomaly, the Cottage Lake lineament, extends at least 18 km and lies approximately on strike with the SWIF on Whidbey Island. Subtle scarps and topographic lineaments on Pleistocene surfaces, visible on high-resolution lidar topography at a number of locations along the SWIF, lie on or near these magnetic anomalies. In the field, scarps exhibit northeast-side-up and vertical relief of 1 to 5 m. Excavations across several lidar scarps lying on or near magnetic anomalies show evidence for multiple folding and faulting events since deglaciation, most likely above buried reverse/oblique faults. Excavations in areas away from magnetic anomalies do not show evidence of tectonic deformation. In total, paleoseismological evidence suggests that the SWIF produced at least four earthquakes since deglaciation about 16,400 years ago, the most recent less than 2700 years ago.

  6. Diet of lowland tapir (Tapirus terrestris) in El Rey National Park, Salta, Argentina.

    PubMed

    Chalukian, Silvia C; de Bustos, M Soledad; Lizárraga, R Leonidas

    2013-03-01

    Lowland tapir (Tapirus terrestris) is the largest herbivore in the Neotropics and, in Argentina, it inhabits a variety of habitats from 100 to 2100 m asl. Lowland tapirs importantly influence their habitat structure because they are selective browsers, seed predators and long-distance seed dispersers. However, increased knowledge of tapir ecology is necessary to support the conservation and management of the species in natural and human-modified environments. Between Jun 2002 and Dec 2008 we assessed the tapir's diet in El Rey National Park, Salta, northwestern Argentina. We collected fresh feces and recorded browsing signs, and we recorded direct observations of tapirs while they were feeding. We analyzed 88 feces samples that had been dried and subsequently weighed. Feces were dominated by fibers and leaves (84.09%), while fruit parts represented a small proportion of the weight (15.91%). During the dry months, a greater percentage of seeds were found in the feces, mainly due to the availability of 3 species of Fabaceae fruits. We recorded a total of 57 plant species from 26 families. Tapirs are adapted to extreme habitats, switching their diet from frugivory to herbivory when fruits are scarce. Considering this, forest remnants and even secondary growth fields should be protected from deforestation. PMID:23586559

  7. Interpretation of gravity anomalies in the northwest Adirondack lowlands, northern New York

    SciTech Connect

    Revetta, F.A.; O'Brian, B. . Geology Dept.)

    1993-03-01

    Twelve hundred gravity measurements were made in the Adirondack Highlands and northwest Adirondack Lowlands, New York between 44[degree]15 minutes and 44[degree]30 minutes N. Latitude and 75[degree]00 minutes W. Longitude. A Bouguer gravity map constructed from the gravity measurements includes the Carthage-Colton Mylonite Zone, a major structural boundary between the highlands and lowlands. The gravity map indicates the gravity contours trend parallel to the CCMZ along most of its length however in some areas the contours cross the boundary. No clear-cut relationships exists between the CCMZ and gravity contours. The Bouguer gravity map shows several prominent gravity anomalies which correlate with the geology seismicity and mineral deposits in the area. Gravity lows of 20 to 30 g.u. are centered over the Gouverneur, Hyde and Payne Lake Alaskite gneiss bodies. A gravity high of 20 g.u. occurs over the Pleasant Lake gabbro pluton. Gravity highs of 35 and 100 g.u. occur over the Sylvia Lake Zinc District and marble just north of the district. A gravity high at Russell, N.Y. coincides with a cluster of nine earthquake epicenters. Finally a steep gravity gradient separates high density rocks from lower density rocks along the Black Lake fault. Two-dimensional computer modeling of the geologic features is underway and quantitative models of the structures will be presented.

  8. Main types of soil degradation in the Kura-Aras Lowland of Azerbaijan

    NASA Astrophysics Data System (ADS)

    Babaev, M. P.; Gurbanov, E. A.; Ramazanova, F. M.

    2015-04-01

    The main types of soil degradation in the Kura-Aras Lowland are irrigation-induced erosion, natural water and wind erosion, and salinization. Among 2098.8 thousand ha of agricultural land in the lowland, the areas of lands subjected to erosion and salinization reach 333.6 and 373.4 thousand ha, respectively. The dependence of irrigation-induced erosion on the soil type (sierozems, meadow sierozems, and gray-cinnamonic soils), the inclination of the irrigation furrows, the irrigation water salinity (0.15-0.95 g/L), and the water discharge (0.8-1.4 L/s) was studied. It was found that soil erosion and salinization result in changes in the soil bulk density and porosity and in a decreasing content of humus and nutrients. Certain changes take place in the soil texture. The land areas subjected to rainstorm erosion of strong, moderate, and low degrees are estimated at 57.7, 24.4, and 15.3 thousand ha, respectively. Measures to control soil erosion and salinization are discussed.

  9. The geography of Vertisols and Vertic soils in the Kuban-Azov Lowland

    NASA Astrophysics Data System (ADS)

    Khitrov, N. B.; Vlasenko, V. P.; Rukhovich, D. I.; Bryzzhev, A. V.; Kalinina, N. V.; Rogovneva, L. V.

    2015-07-01

    The soils shown on Russian soil maps of the Kuban-Azov Lowland under the names of slitic (vertic) and compacted soils contain diagnostic features characteristic of the type of dark slitozems and subtypes of slitic soils in the new Russian soil classification system, or Vertisols and Vertic soils in the WRB system. These are slickensides, wedge-shaped structure, clayey texture through the entire soil profile, and shrinkage cracks formed during soil drying. It was found that dark quasi-gley slitozems (Vertisols) occur in the central parts of the bottoms of large (> 1.5 km along the longest axis) closed depressions. Humus quasi-gley slitozems (Vertic Stagnic Phaeozems (Clayic, Pachic)) are confined to the peripheral parts of the bottoms of these depressions and to the bottoms of smaller (0.8-1.5 km) closed depressions. Deeply slitic humus—quasi-gley soils and deeply slitic clay-illuvial chernozems (Bathyvertic Stagnic Phaeozems (Clayic, Pachic)), in which the upper boundary of slickensides is found at the depths from 100 to 200 cm, usually occur in the bottoms of closed depressions with the longest axis of less than 0.6-0.8 km and in the bottoms and on slopes of shallow flat-bottomed ravines. With respect to the distribution of Vertisols and Vertic soils, the Kuban-Azov Lowland can be subdivided into eight soil districts. In five of them, these soils occupy from 0.1% to 12.1% of the territory.

  10. Comparison of physiological responses to hypoxia at high altitudes between highlanders and lowlanders.

    PubMed

    Zhongyuan, S; Xuehan, N; Pengguo, H; Shoucheng, Z; Deming, Z; Shengyue, Y; Yan, W; Zhaoshen, D

    1979-12-01

    This report deals with the differences and changes of physiological functions of the highlanders and the lowlanders at different altitudes during the period when the Chinese Mountaineering Team was climbing up and reached the peak of Qomolangma Feng. In a period of relaxation, there are no significant changes in ventilatory responsiveness to hypercapnia, electrocardiogram and electroencephalogram between highlanders and lowlanders with the changes at different altitudes. At 5,000 m a.s.l., however, electrocardiogram and the result of cardiac ventricular functional test show significant differences after the subjects are physically loaded. Those whose electrocardiogram readings show unusual changes, and whose cardiac ventricular functional tests show their physiological functions at low degree after physical activities at the altitude of 5,000 m, have a climbing ability hardly below 6,500 m, while those who have reached the altitudes above 8,200 m have no unusual changes in electrocardiogram, and the results of cardiac ventricular functional tests show that their physiological functions are at high degree. PMID:534322

  11. Genetic Differentiation in Insular Lowland Rainforests: Insights from Historical Demographic Patterns in Philippine Birds

    PubMed Central

    Sánchez-González, Luis Antonio; Hosner, Peter A.; Moyle, Robert G.

    2015-01-01

    Phylogeographic studies of Philippine birds support that deep genetic structure occurs across continuous lowland forests within islands, despite the lack of obvious contemporary isolation mechanisms. To examine the pattern and tempo of diversification within Philippine island forests, and test if common mechanisms are responsible for observed differentiation, we focused on three co-distributed lowland bird taxa endemic to Greater Luzon and Greater Negros-Panay: Blue-headed Fantail (Rhipidura cyaniceps), White-browed Shama (Copsychus luzoniensis), and Lemon-throated Leaf-Warbler (Phylloscopus cebuensis). Each species has two described subspecies within Greater Luzon, and a single described subspecies on Greater Negros/Panay. Each of the three focal species showed a common geographic pattern of two monophyletic groups in Greater Luzon sister to a third monophyletic group found in Greater Negros-Panay, suggesting that common or similar biogeographic processes may have produced similar distributions. However, studied species displayed variable levels of mitochondrial DNA differentiation between clades, and genetic differentiation within Luzon was not necessarily concordant with described subspecies boundaries. Population genetic parameters for the three species suggested both rapid population growth from small numbers and geographic expansion across Luzon Island. Estimates of the timing of population expansion further supported that these events occurred asynchronously throughout the Pleistocene in the focal species, demanding particular explanations for differentiation, and support that co-distribution may be secondarily congruent. PMID:26312748

  12. An insight into pre-Columbian raised fields: the case of San Borja, Bolivian lowlands

    NASA Astrophysics Data System (ADS)

    Rodrigues, Leonor; Lombardo, Umberto; Trauerstein, Mareike; Huber, Perrine; Mohr, Sandra; Veit, Heinz

    2016-07-01

    Pre-Columbian raised field agriculture in the tropical lowlands of South America has received increasing attention and been the focus of heated debates regarding its function, productivity, and role in the development of pre-Columbian societies. Even though raised fields are all associated to permanent or semi-permanent high water levels, they occur in different environmental contexts. Very few field-based studies on raised fields have been carried out in the tropical lowlands and little is known about their use and past management. Based on topographic surveying and mapping, soil physical and chemical analysis and OSL and radiocarbon dating, this paper provides insight into the morphology, functioning and time frame of the use of raised fields in the south-western Llanos de Moxos, Bolivian Amazon. We have studied raised fields of different sizes that were built in an area near the town of San Borja, with a complex fluvial history. The results show that differences in field size and height are the result of an adaptation to a site where soil properties vary significantly on a scale of tens to hundreds of metres. The analysis and dating of the raised fields sediments point towards an extensive and rather brief use of the raised fields, for about 100-200 years at the beginning of the 2nd millennium.

  13. Cultural Phylogenetics of the Tupi Language Family in Lowland South America

    PubMed Central

    Walker, Robert S.; Wichmann, Søren; Mailund, Thomas; Atkisson, Curtis J.

    2012-01-01

    Background Recent advances in automated assessment of basic vocabulary lists allow the construction of linguistic phylogenies useful for tracing dynamics of human population expansions, reconstructing ancestral cultures, and modeling transition rates of cultural traits over time. Methods Here we investigate the Tupi expansion, a widely-dispersed language family in lowland South America, with a distance-based phylogeny based on 40-word vocabulary lists from 48 languages. We coded 11 cultural traits across the diverse Tupi family including traditional warfare patterns, post-marital residence, corporate structure, community size, paternity beliefs, sibling terminology, presence of canoes, tattooing, shamanism, men's houses, and lip plugs. Results/Discussion The linguistic phylogeny supports a Tupi homeland in west-central Brazil with subsequent major expansions across much of lowland South America. Consistently, ancestral reconstructions of cultural traits over the linguistic phylogeny suggest that social complexity has tended to decline through time, most notably in the independent emergence of several nomadic hunter-gatherer societies. Estimated rates of cultural change across the Tupi expansion are on the order of only a few changes per 10,000 years, in accord with previous cultural phylogenetic results in other language families around the world, and indicate a conservative nature to much of human culture. PMID:22506065

  14. Modified Whittaker plots as an assessment and monitoring tool for vegetation in a lowland tropical rainforest.

    PubMed

    Campbell, Patrick; Comiskey, James; Alonso, Alfonso; Dallmeier, Francisco; Nuñez, Percy; Beltran, Hamilton; Baldeon, Severo; Nauray, William; de la Colina, Rafael; Acurio, Lucero; Udvardy, Shana

    2002-05-01

    Resource exploitation in lowland tropical forests is increasing and causing loss of biodiversity. Effective evaluation and management of the impacts of development on tropical forests requires appropriate assessment and monitoring tools. We propose the use of 0.1-ha multi-scale, modified Whittaker plots (MWPs) to assess and monitor vegetation in lowland tropical rainforests. We established MWPs at 4 sites to: (1) describe and compare composition and structure of the sites using MWPs, (2) compare these results to those of 1-ha permanent vegetation plots (BDPs), and (3) evaluate the ability of MWPs to detect changes in populations (statistical power). We recorded more than 400 species at each site. Species composition among the sites was distinctive, while mean abundance and basal area was similar. Comparisons between MWPs and BDPs show that they record similar species composition and abundance and that both perform equally well at detecting rare species. However, MWPs tend to record more species, and power analysis studies show that MWPs were more effective at detecting changes in the mean number of species of trees > or = 10 cm in diameter at breast height (dbh) and in herbaceous plants. Ten MWPs were sufficient to detect a change of 11% in the mean number of herb species, and they were able to detect a 14% change in the mean number of species of trees > or =10 cm dbh. The value of MWPs for assessment and monitoring is discussed, along with recommendations for improving the sampling design to increase power. PMID:12125748

  15. Spectral reflectance of rice seedlings

    NASA Astrophysics Data System (ADS)

    Adams, Alois J.; Herden, Deborah

    1999-01-01

    The spectral reflectance of young rice plants was measured in the visible and near-IR region of the spectrum using a commercially available fiber optic contact probe and miniature spectrometer. This work aims to identify an empirical spectral index which changes when rice is exposed to increased levels of chloride anions in the irrigation water and soil. The ratio of near IR reflectance to that of green, R750/555 is known to be a quantitative measure of chlorophyll content in the leaf but int his study does not show a consistent shift for sample which are exposed to chloride levels equal to or less than 0.1 percent by mass of soil. However, leaf contact spectral reflectance measurements did reveal a significant and consistent increase in R750/555 along the length of the leaves, and this variation should represent an important factor in modeling remote and proximal sensing data.

  16. Rice, Japonica (Oryza sativa L.).

    PubMed

    Main, Marcy; Frame, Bronwyn; Wang, Kan

    2015-01-01

    The importance of rice, as a food crop, is reflected in the extensive global research being conducted in an effort to improve and better understand this particular agronomic plant. In regard to biotechnology, this has led to the development of numerous genetic transformation protocols. Over the years, many of these methods have become increasingly straightforward, rapid, and efficient, thereby making rice valuable as a model crop for scientific research and functional genomics. The focus of this chapter is on one such protocol that uses Agrobacterium-mediated transformation of Oryza sativa L. ssp. Japonica cv. Nipponbare with an emphasis on tissue desiccation. The explants consist of callus derived from mature seeds which are cocultivated on filter paper postinfection. Hygromycin selection is used for the recovery of subsequent genetically engineered events. PMID:25300839

  17. Water harvesting experience in sub-Saharan Africa - lessons for sustainable intensification of rainfed agriculture and the influence of available soils and rainfall data

    NASA Astrophysics Data System (ADS)

    Gowin, John; Bunclark, Lisa

    2013-04-01

    Africa is seen by many as the continent with the greatest potential for agricultural growth, but land degradation and environmental change threaten the African soil resource more severely than in many other regions of the planet. Achieving future food security will depend mainly on increasing production from rainfed agriculture. The challenge of delivering the required sustainable intensification in rainfed agriculture is most acute in the drylands - the semi-arid and dry sub-humid climatic regions. There are two broad strategies for increasing yields under these circumstances: (1) capturing more rainwater and storing it (increasing water availability), and (2) using the available water more effectively by increasing the plant growth and/or reducing non-productive soil evaporation (increasing water productivity). We focus on the first of these options - water harvesting, which is defined as, "the collection and concentration of rainfall runoff, or floodwaters, for plant production". The benefits of water harvesting have been documented from small scale experimental plot studies, but evidence of successful adoption and impact is weak. As a contribution to improving the evidence base, we present results from an investigation conducted in SSA to gather information on progress with efforts to promote adoption of water harvesting. The intention was to investigate in detail the processes and outcomes on a large enough sample area to draw some common conclusions. This was not a comprehensive analysis of all that is happening in each country, nor was it a random sample; this was a purposive sample guided by available baseline information to permit comparative analysis. Water harvesting seems to have made the most progress where techniques can be adopted by individual farmers: in Burkina Faso and Niger micro- scale zaï /tassa and demi-lune systems; in Sudan and Tanzania meso-scale majaruba and teras systems. Macro-scale systems requiring social organisation may offer

  18. [Extraction and purification method of rice DNA from rice powder containing Konjak flour].

    PubMed

    Minematsu, Kazuhiko; Nakamura, Kosuke; Akiyama, Hiroshi; Harikai, Naoki; Nakajima, Osamu; Kitta, Kazumi; Teshima, Reiko; Iizuka, Tayoshi

    2010-01-01

    Rice powder containing Konjak flour made with tuberous roots of Amorphophallus konjac is imported as a rice-processed product from China to Japan. An improved DNA purification method for the polymerase chain reaction (PCR) analysis of rice in such products is necessary, since Konjak flour constituents absorb the DNA purification buffer to form a gel, and cause problems in the subsequent purification steps. Here, we present a simple preparative system for isolation of the rice and a purification method of the rice DNA from the product. The purified DNA was confirmed to be a good template for both PCR and real-time PCR. PMID:21071909

  19. Changes in CH4 emission from rice fields from 1960 to 1990s. 1. Impacts of modern rice technology

    NASA Astrophysics Data System (ADS)

    van der Gon, Hugo Denier

    2000-03-01

    Four countries (Indonesia, Philippines, Thailand, and Nepal) were taken as an example to assess the impact of changes in rice cultivation on methane emissions from rice fields since the 1960s. The change of rice area by type of culture from 1960-1990s is estimated, and its relative contribution to national harvested rice area is calculated and multiplied with an emission factor, to derive the relative methane emission per unit rice land. Relative methane emission per ha rice land has increased since 1960 for all four countries, largely due to an increase in irrigated rice area and partly due to a decrease in upland rice area. Patterns of rice area changes and related emission changes differ considerably among countries. On the basis of the rice area increases between 1960 and the 1990s, significant increases in methane emissions from rice fields due to increases in total rice cultivated area are not to be expected in the future. The impact of modern rice variety adoption is assessed by relating methane emissions to rice production. The organic matter returned to the paddy soil is largely determined by rice biomass production which, given a certain yield, is different for traditional and modern rice varieties. By calculating total organic matter returned to rice paddy soils and assuming a constant fraction to be emitted as methane, rice production and methane emission can be related. The analysis indicates that (1) up to now, rice yield increases in countries with high modern rice variety adoption have not resulted in increased methane emissions per unit of harvested area and, (2) global annual emission from rice fields may be considerably lower than generally assumed. The introduction of modern rice varieties can be regarded as a historical methane emission mitigation strategy because higher rice yields resulted in lower or equal methane emissions.

  20. Changes in CH4 emission from rice fields from 1960 to 1990s: 1. Impacts of modern rice technology

    NASA Astrophysics Data System (ADS)

    Gon, Hugo Denier

    2000-03-01

    Four countries (Indonesia, Philippines, Thailand, and Nepal) were taken as an example to assess the impact of changes in rice cultivation on methane emissions from rice fields since the 1960s. The change of rice area by type of culture from 1960-1990s is estimated, and its relative contribution to national harvested rice area is calculated and multiplied with an emission factor, to derive the relative methane emission per unit rice land. Relative methane emission per ha rice land has increased since 1960 for all four countries, largely due to an increase in irrigated rice area and partly due to a decrease in upland rice area. Patterns of rice area changes and related emission changes differ considerably among countries. On the basis of the rice area increases between 1960 and the 1990s, significant increases in methane emissions from rice fields due to increases in total rice cultivated area are not to be expected in the future. The impact of modern rice variety adoption is assessed by relating methane emissions to rice production. The organic matter returned to the paddy soil is largely determined by rice biomass production which, given a certain yield, is different for traditional and modern rice varieties. By calculating total organic matter returned to rice paddy soils and assuming a constant fraction to be emitted as methane, rice production and methane emission can be related. The analysis indicates that (1) up to now, rice yield increases in countries with high modern rice variety adoption have not resulted in increased methane emissions per unit of harvested area and, (2) global annual emission from rice fields may be considerably lower than generally assumed. The introduction of modern rice varieties can be regarded as a historical methane emission mitigation strategy because higher rice yields resulted in lower or equal methane emissions.

  1. Preferential association of endophytic bradyrhizobia with different rice cultivars and its implications for rice endophyte evolution.

    PubMed

    Piromyou, Pongdet; Greetatorn, Teerana; Teamtisong, Kamonluck; Okubo, Takashi; Shinoda, Ryo; Nuntakij, Achara; Tittabutr, Panlada; Boonkerd, Nantakorn; Minamisawa, Kiwamu; Teaumroong, Neung

    2015-05-01

    Plant colonization by bradyrhizobia is found not only in leguminous plants but also in nonleguminous species such as rice. To understand the evolution of the endophytic symbiosis of bradyrhizobia, the effect of the ecosystems of rice plantations on their associations was investigated. Samples were collected from various rice (Oryza sativa) tissues and crop rotational systems. The rice endophytic bradyrhizobia were isolated on the basis of oligotrophic properties, selective medium, and nodulation on siratro (Macroptilium atropurpureum). Six bradyrhizobial strains were obtained exclusively from rice grown in a crop rotational system. The isolates were separated into photosynthetic bradyrhizobia (PB) and nonphotosynthetic bradyrhizobia (non-PB). Thai bradyrhizobial strains promoted rice growth of Thai rice cultivars better than the Japanese bradyrhizobial strains. This implies that the rice cultivars possess characteristics that govern rice-bacterium associations. To examine whether leguminous plants in a rice plantation system support the persistence of rice endophytic bradyrhizobia, isolates were tested for legume nodulation. All PB strains formed symbioses with Aeschynomene indica and Aeschynomene evenia. On the other hand, non-PB strains were able to nodulate Aeschynomene americana, Vigna radiata, and M. atropurpureum but unable to nodulate either A. indica or A. evenia. Interestingly, the nodABC genes of all of these bradyrhizobial strains seem to exhibit low levels of similarity to those of Bradyrhizobium diazoefficiens USDA110 and Bradyrhizobium sp. strain ORS285. From these results, we discuss the evolution of the plant-bradyrhizobium association, including nonlegumes, in terms of photosynthetic lifestyle and nod-independent interactions. PMID:25710371

  2. Preferential Association of Endophytic Bradyrhizobia with Different Rice Cultivars and Its Implications for Rice Endophyte Evolution

    PubMed Central

    Piromyou, Pongdet; Greetatorn, Teerana; Teamtisong, Kamonluck; Okubo, Takashi; Shinoda, Ryo; Nuntakij, Achara; Tittabutr, Panlada; Boonkerd, Nantakorn

    2015-01-01

    Plant colonization by bradyrhizobia is found not only in leguminous plants but also in nonleguminous species such as rice. To understand the evolution of the endophytic symbiosis of bradyrhizobia, the effect of the ecosystems of rice plantations on their associations was investigated. Samples were collected from various rice (Oryza sativa) tissues and crop rotational systems. The rice endophytic bradyrhizobia were isolated on the basis of oligotrophic properties, selective medium, and nodulation on siratro (Macroptilium atropurpureum). Six bradyrhizobial strains were obtained exclusively from rice grown in a crop rotational system. The isolates were separated into photosynthetic bradyrhizobia (PB) and nonphotosynthetic bradyrhizobia (non-PB). Thai bradyrhizobial strains promoted rice growth of Thai rice cultivars better than the Japanese bradyrhizobial strains. This implies that the rice cultivars possess characteristics that govern rice-bacterium associations. To examine whether leguminous plants in a rice plantation system support the persistence of rice endophytic bradyrhizobia, isolates were tested for legume nodulation. All PB strains formed symbioses with Aeschynomene indica and Aeschynomene evenia. On the other hand, non-PB strains were able to nodulate Aeschynomene americana, Vigna radiata, and M. atropurpureum but unable to nodulate either A. indica or A. evenia. Interestingly, the nodABC genes of all of these bradyrhizobial strains seem to exhibit low levels of similarity to those of Bradyrhizobium diazoefficiens USDA110 and Bradyrhizobium sp. strain ORS285. From these results, we discuss the evolution of the plant-bradyrhizobium association, including nonlegumes, in terms of photosynthetic lifestyle and nod-independent interactions. PMID:25710371

  3. Analysis of rice Act1 5' region activity in transgenic rice plants.

    PubMed Central

    Zhang, W; McElroy, D; Wu, R

    1991-01-01

    The 5' region of the rice actin 1 gene (Act1) has been developed as an efficient regulator of foreign gene expression in transgenic rice plants. To determine the pattern and level of rice Act1 5' region activity, transgenic rice plants containing the Act1 5' region fused to a bacterial beta-glucuronidase (Gus) coding sequence were generated. Two independent clonal lines of transgenic rice plants were analyzed in detail. Quantitative analysis showed that tissue from these transgenic rice plants have a level of GUS protein that represents as much as 3% of total soluble protein. We were able to demonstrate that Act1-Gus gene expression is constitutive throughout the sporophytic and gametophytic tissues of these transgenic rice plants. Plants from one transgenic line were analyzed for the segregation of GUS activity in pollen by in situ histochemical staining, and the inheritance and stability of Act1-Gus expression were assayed in subsequently derived progeny plants. PMID:1821763

  4. Rice genomes recorded ancient pararetrovirus activities: Virus genealogy and multiple origins of endogenization during rice speciation.

    PubMed

    Chen, Sunlu; Liu, Ruifang; Koyanagi, Kanako O; Kishima, Yuji

    2014-12-01

    Viral fossils in rice genomes are a best entity to understand ancient pararetrovirus activities through host plant history because of our advanced knowledge of the genomes and evolutionary history with rice and its related species. Here, we explored organization, geographic origins and genealogy of rice pararetroviruses, which were turned into endogenous rice tungro bacilliform virus-like (eRTBVL) sequences. About 300 eRTBVL sequences from three representative rice genomes were clearly classified into six families. Most of the endogenization events of the eRTBVLs were initiated before differentiation of the rice progenitor (> 160,000 years ago). We successfully followed the genealogy of old relic viruses during rice speciation, and inferred the geographical origins for these viruses. Possible virus genomic sequences were explained mostly by recombinations between different virus families. Interestingly, we discovered that only a few recombination events among the numerous occasions had determined the virus genealogy. PMID:25461539

  5. Three Dimensional Wind Speed and Flux Measurement over a Rain-fed Soybean Field Using Orthogonal and Non-orthogonal Sonic Anemometer Designs

    NASA Astrophysics Data System (ADS)

    Thomas, T.; Suyker, A.; Burba, G. G.; Billesbach, D.

    2014-12-01

    The eddy covariance method for estimating fluxes of trace gases, energy and momentum in the constant flux layer above a plant canopy fundamentally relies on accurate measurements of the vertical wind speed. This wind speed is typically measured using a three dimensional ultrasonic anemometer. These anemometers incorporate designs with transducer sets that are aligned either orthogonally or non-orthogonally. Previous studies comparing the two designs suggest differences in measured 3D wind speed components, in particular vertical wind speed, from the non-orthogonal transducer relative to the orthogonal design. These differences, attributed to additional flow distortion caused by the non-orthogonal transducer arrangement, directly affect fluxes of trace gases, energy and momentum. A field experiment is being conducted over a rain-fed soybean field at the AmeriFlux site (US-Ne3) near Mead, Nebraska. In this study, ultrasonic anemometers featuring orthogonal transducer sets (ATI Vx Probe) and non-orthogonal transducer sets (Gill R3-100) collect high frequency wind vector and sonic temperature data. Sensible heat and momentum fluxes and other key sonic performance data are evaluated based on environmental parameters including wind speed, wind direction, temperature, and angle of attack. Preliminary field experiment results are presented.

  6. CHANGES IN LOWLAND FLOODPLAIN SEDIMENTATION PROCESSES: PRE-DISTURBANCE TO POST-REHABILITATION, COSUMNES RIVER, CA. (R825433)

    EPA Science Inventory

    During the late Holocene, sediment deposition on the lowland Cosumnes River floodplain, CA has depended on factors that varied temporally and spatially, such as basin subsidence, sea level rise, flow, and sediment supply from both the Sacramento River system and from the Cosum...

  7. Long-term persistence of synthetic populations of a lowland switchgrass ecotype and the cultivar Cave-in-Rock

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Upland cultivars of switchgrass (Panicum virgatum L.), such as ‘Cave-in-Rock’, are most frequently recommended for the northeastern USA. Lowland ecotypes typically originate from more southerly locations and have coarser stems than upland ecotypes. Long-term data on the persistence and yield of lowl...

  8. Incorporating landscape depressions and tile drainages of a northern German lowland catchment into a semi-distributed model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydrological models need to be adapted to specific hydrological characteristics of the catchment in which they are applied. In the lowland region of northern Germany, tile drains and depressions are prominent features of the landscape though are often neglected in hydrological modelling on the catch...

  9. Hydrolutos piaroa sp.n. (Orthoptera: Anostostomatidae), a new semiaquatic Lutosini species from south-western Venezuelan lowland streams.

    PubMed

    Derka, Tomáš; Svitok, Marek; Fedor, Peter

    2016-01-01

    Hydrolutos piaroa, a new species of Lutosini (Orthoptera: Anostostomatidae) from Tobogán de la Selva (Puerto Ayacucho region, SW Venezuela) is described and figured. Inhabiting aquatic environment it represents an unusual orthopteran with sternal and pleural area covered by fine microtrichia, forming a plastron. This is the first known Hydrolutos species sampled in lowland streams of Venezuelan Guayana. PMID:27395849

  10. Bd on the beach: high prevalence of Batrachochytrium dendrobatidis in the lowland forests of Gorgona Island (Colombia, South America).

    PubMed

    Flechas, Sandra Victoria; Sarmiento, Carolina; Amézquita, Adolfo

    2012-09-01

    The amphibian chytrid fungus, Batrachochytrium dendrobatidis, Bd, has been implicated in the decimation and extinction of many amphibian populations worldwide, especially at mid and high elevations. Recent studies have demonstrated the presence of the pathogen in the lowlands from Australia and Central America. We extend here its elevational range by demonstrating its presence at the sea level, in the lowland forests of Gorgona Island, off the Pacific coast of Colombia. We conducted two field surveys, separated by four years, and diagnosed Bd by performing polymerase chain reactions on swab samples from the skin of five amphibian species. All species, including the Critically Endangered Atelopus elegans, tested positive for the pathogen, with prevalences between 3.9 % in A. elegans (in 2010) and 52 % in Pristimantis achatinus. Clinical signs of chytridiomycosis were not detected in any species. To our knowledge, this is the first report of B. dendrobatidis in tropical lowlands at sea level, where temperatures may exceed optimal growth temperatures of this pathogen. This finding highlights the need to understand the mechanisms allowing the interaction between frogs and pathogen in lowland ecosystems. PMID:22669408

  11. A Very Large Population of Likely Buried Impact Basins in the Northern Lowlands of Mars Revealed by MOLA Data

    NASA Technical Reports Server (NTRS)

    Frey, H. V.; Shockey, K. M.; Frey, E. L.; Roark, J. H.; Sakimoto, S. E. H.

    2001-01-01

    High resolution Mars Orbiter Laser Altimeter (MOLA) data have revealed a large number of subdued quasi-circular depressions (QCDs) >50 km diameter in the northern lowlands of Mars which are generally not visible in Viking imagery and which may be buried ancient impact basins. Additional information is contained in the original extended abstract.

  12. Four new rice varieties for specialty markets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although conventional long grain rice varieties are grown on over 75% of the acreage in the US, there is interest in developing rice cultivars which possess specific qualities required for certain value-added markets. USDA ARS researchers at Beaumont, TX and Stuttgart, AR, in various collaborations ...

  13. [Amino acid composition of rice grain proteins].

    PubMed

    Peruanskiĭ, Iu V; Savich, I M

    1976-01-01

    The composition of the major reserve proteins of rice grain--globulins, prolamines and glutelins--was examined in four rice varieties (Dubovsky 129, Kuban 3, Alakul, Ushtobinsky). Globulins proved to be most heterogeneous whereas glutelins appeared to be least heterogeneous. In regards to the ratio of components globulins showed high variability and glutelins displayed high stability. PMID:1005365

  14. Grain Unloading Of Arsenic Species In Rice

    EPA Science Inventory

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dim...

  15. 33 CFR 117.324 - Rice Creek.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Rice Creek. 117.324 Section 117.324 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.324 Rice Creek. The CSX Railroad Swingbridge,...

  16. 33 CFR 117.324 - Rice Creek.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Rice Creek. 117.324 Section 117.324 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.324 Rice Creek. The CSX Railroad Swingbridge,...

  17. 33 CFR 117.324 - Rice Creek.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Rice Creek. 117.324 Section 117.324 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.324 Rice Creek. The CSX Railroad Swingbridge,...

  18. 33 CFR 117.324 - Rice Creek.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Rice Creek. 117.324 Section 117.324 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.324 Rice Creek. The CSX Railroad Swingbridge,...

  19. 33 CFR 117.324 - Rice Creek.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Rice Creek. 117.324 Section 117.324 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.324 Rice Creek. The CSX Railroad Swingbridge,...

  20. Simulating rice response to climate change

    SciTech Connect

    Singh, U.; Padilla, J.L. |

    1995-12-31

    The response of rice (Oryza sativa L.) to elevated CO{sub 2} concentration and temperature increase was simulated using the CERES-rice model. CERES-rice belongs to the International Benchmark Sites Network for Agrotechnology Transfer (IBSNAT) family of crop and nutrient dynamics models. Long-term historical data from the International Rice Research Institute (IRRI) wetland site was used to quantify the climatic change effects. The model simulated such beneficial effects of CO{sub 2} enrichment as increased grain yields, reduced transpiration, increased water use efficiency, improved use of intercepted radiation, reduced N losses, and higher N use efficiency. The trends were reversed for all of the above parameters with increase in temperature. CERES-rice simulated these negative trends in low input rice production as well. Based on the model`s prediction, some of the negative effects of temperature increase in warmer regions of the world could be offset by use of rice varieties that are tolerant to high temperature-induced spikelet sterility, and planting varieties with longer growth duration, particularly, longer grain filling duration. With improved varieties and good management future impact of climate change could be capitalized to have positive effects on rice production. Although the model has been extensively tested, it is critical to validate it with field data from extreme temperature and CO{sub 2} level studies. 33 refs., 13 figs., 3 tabs.

  1. Novel gene expression tools for rice biotechnology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biotechnology is an effective and important method of improving both quality and agronomic traits in rice. We are developing novel molecular tools for genetic engineering, with a focus on developing novel transgene expression control elements (i.e. promoters) for rice. A suite of monocot grass promo...

  2. Important sensory properties differentiating premium rice cultivars.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In rice-consuming countries worldwide, specific cultivars are recognized as premium, “gold standard” cultivars, while others are recognized as being superior, but not the best. It has been difficult to ascertain whether preferences for premium rice cultivars are driven by discernable differences in...

  3. Rice University: College and University Systems Environment.

    ERIC Educational Resources Information Center

    CAUSE/EFFECT, 1984

    1984-01-01

    Computing began at Rice University with the first computer project on campus about 1958. In 1960 a computer center was formed. Today's Institute for Computer Services and Applications serves Rice administration, departments, faculty, and students by writing systems, maintaining files, entering data, retrieving information, etc. (MLW)

  4. Evolutionary Genomics Of Invasive Weedy Rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice is an interfertile, weedy form of cultivated rice (Oryza sativa) that competes aggressively with the crop in the southern U.S., reducing yields and contaminating harvests. Weed strains range from ‘crop mimics,’ which share many domestication traits with the crop, to strains closely resembli...

  5. Rice blast evaluation of newly introduced germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic resistance to the rice blast fungus, Magnaporthe oryzae (anamorph Pyricularia grisea oryzae) was identified in newly introduced rice germplasm through quarantine when tested in artificially inoculated greenhouse and field nursery tests during the 2007 growing season. Of 229 accessions, 31 we...

  6. Connecting with Rice: Carolina Lowcountry and Africa

    ERIC Educational Resources Information Center

    Mitchell, Jerry T.; Collins, Larianne; Wise, Susan S.; Caughman, Monti

    2012-01-01

    Though lasting less than 200 years, large-scale rice production in South Carolina and Georgia "probably represented the most significant utilization of the tidewater zone for crop agriculture ever attained in the United States." Rice is a specialty crop where successful cultivation relied heavily upon "adaptation" to nature via imported…

  7. Low oil-uptake rice batters.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice starch and flour are popular for use in foods, because they are known to be nutritious, gluten-free, and hypoallergenic – properties which make them particularly desirable for use in infant foods, and in products for people with celiac disease (gluten intolerance). One application for rice sta...

  8. RICE BREAD FOR PEOPLE WITH CELIAC DISEASE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This technical bulletin was written to describe new process to make whole rice bread (WRB) for Celiacs, a disease caused by proteins found in wheat, barley and rye. The rice is free of these proteins and hence an ideal grain to develop foods for Celiacs. Absence of these proteins, however make it ...

  9. Rice yield estimation using Landsat ETM+ Data

    NASA Astrophysics Data System (ADS)

    Siyal, Altaf Ali; Dempewolf, Jan; Becker-Reshef, Inbal

    2015-01-01

    Paddy rice areas in Larkana district in Sindh province, Pakistan, were mapped over eight years. Landsat 7 ETM+ satellite imagery was classified for rice areas using training data collected through visual interpretation and using a bagged decision tree approach. Within the rice areas, we estimated yield for the 2013 season using regression models based on Landsat-derived normalized difference vegetation index (NDVI) and ratio vegetation index (RVI) values against historic, reported yield values. The annual cropped rice area estimated from satellite imagery was between 19% and 24% lower than the area reported by the Crop Reporting Service, Sindh. A positive and strong relationship with coefficient of determination (R2) of 0.94 was observed between the reported rice crop yield and NDVI at the peak of the growing season for the years 2006 to 2013. A fair relation (R2=0.875) between rice crop yield and RVI was observed for the same years. A strong relationship between observed and predicted rice production with model efficiency=0.925, mean bias error=-85,016 t, and RMSE=80,726 t was obtained. Thus, Landsat ETM+ has a high potential for estimating rice yield and production at the district level in Pakistan and elsewhere.

  10. Landscape characteristics impacts on water quality of urban lowland catchments: monitoring the Amsterdam city area

    NASA Astrophysics Data System (ADS)

    Yu, Liang; van der Vlugt, Corné; Rozemeijer, Joachim; Broers, Hans Peter; van Breukelen, Boris; Ouboter, Maarten; Stuyfzand, Pieter

    2015-04-01

    In Dutch lowland polder systems, groundwater quality significantly contributes to surface water quality. This process is influenced by landscape characteristics such as topography, geology, and land use types. In this study, 23 variables were selected for 144 polder catchments, including groundwater and surface water solute concentrations (TN, TP, NH4+, NO3-, HCO3-, SO42-, Ca2+, Cl-), seepage rate in mm per year, elevation, paved area percentage, surface water area percentage, and soil types (calcite, humus and lutum percentage). The spatial patters in groundwater and surface water quality can largely be explained by groundwater seepage rates in polders and partly by artificial redistribution of water via the regional surface water system. High correlations (R2 up to 0.66) between solutes in groundwater and surface water revealed their probable interaction. This was further supported by results from principal component analysis (PCA) and linear regression. The PCA distinguished four factors that were related to a fresh groundwater factor, seepage rate factor, brackish groundwater factor and clay soil factor. Nutrients (TP, TN, NH4+ and NO3-) and SO42- in surface water bodies are mainly determined by groundwater quality combined with seepage rate, which is negatively related to surface water area percentage and elevation of the catchment. This pattern is more obvious in deep urban lowland catchments. Relatively high NO3- loads more tend to appear in catchments with high humus, but low calcite percentage soil type on top, which was attributed to clay soil type that was expressed by calcite percentage in our regression. Different from nitrogen contained solutes, TP is more closely related to fresh groundwater quality than to seepage rate. Surface water Cl- concentration has a high relation with brackish groundwater. Due to the artificial regulation of flow direction, brackish inlet water from upstream highly influences the chloride load in surface water bodies

  11. Vegetation and floristics of a lowland tropical rainforest in northeast Australia

    PubMed Central

    Apgaua, Deborah M. G.; Campbell, Mason J; Cox, Casey J; Crayn, Darren M; Ishida, Françoise Y; Laidlaw, Melinda J; Liddell, Michael J; Seager, Michael; Laurance, Susan G. W.

    2016-01-01

    Abstract Background Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m2 quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m2 ha-1, of which small stems (tree saplings and shrubs <10cm dbh) and lianas collectively contribute c.4.2%. Comparing the stem density-diversity patterns of the DRO forest with other tropical rainforests globally, our meta-analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. New information We present a floristic checklist, a

  12. Holocene Biomass Burning, Environmental Change, and Human Land Use in the Southern Maya Lowlands

    NASA Astrophysics Data System (ADS)

    Anderson, L.; Wahl, D.

    2013-12-01

    For several decades scholars have studied the dynamic relationship between the prehispanic Maya and their environment in order to test hypotheses that environmental change played a role in the abandonment of the Maya lowlands. Fire was inherent in Maya land use practices, arguably the primary tool used to alter the landscape and extract resources. Opening of forest for agriculture, building, and extraction/production of construction material necessitated burning. The extensive production of lime plaster for architectural and domestic use demanded harvesting and burning of vast quantities of green wood. While we understand the fundamental role of fire in Maya land use, there are very few records of prehispanic biomass burning from the Maya lowlands. Consequently, only a limited understanding exists of both natural fire regimes and patterns of anthropogenic burning in the tropical dry forests of Central America. Here we report two new well-dated, high-resolution records of biomass burning based on analysis of fossil charcoal recovered from lacustrine sediment cores, extending from the early Holocene to the present. The study sites, Lagos Paixban and Puerto Arturo are located in the southern Maya lowlands in modern northern Peten, Guatemala. Macroscopic charcoal data are presented along with previously published proxy data from the sites, and interpreted in the context of existing regional and local paleoenvironmental and archeological records. Results show that frequent fires occurred in the closed canopy forests of the region since at least the early mid-Holocene (~9000 BP), prior to occupation by sedentary agriculturalists. Following the arrival of sedentary agriculture at around 4600 BP, the system transitioned from climate controlled to anthropogenic control. During the Maya period, changes in fire regime are muted and do not appear to be driven by changes in climate conditions. Low charcoal influx and fire frequency in the Preclassic period suggest that land use

  13. Investigating Appropriate Sampling Design for Estimating Above-Ground Biomass in Bruneian Lowland Mixed Dipterocarp Forest

    NASA Astrophysics Data System (ADS)

    Lee, S.; Lee, D.; Abu Salim, K.; Yun, H. M.; Han, S.; Lee, W. K.; Davies, S. J.; Son, Y.

    2014-12-01

    Mixed tropical forest structure is highly heterogeneous unlike plantation or mixed temperate forest structure, and therefore, different sampling approaches are required. However, the appropriate sampling design for estimating the above-ground biomass (AGB) in Bruneian lowland mixed dipterocarp forest (MDF) has not yet been fully clarified. The aim of this study was to provide supportive information in sampling design for Bruneian forest carbon inventory. The study site was located at Kuala Belalong lowland MDF, which is part of the Ulu Tembulong National Park, Brunei Darussalam. Six 60 m × 60 m quadrats were established, separated by a distance of approximately 100 m and each was subdivided into quadrats of 10 m × 10 m, at an elevation between 200 and 300 m above sea level. At each plot all free-standing trees with diameter at breast height (dbh) ≥ 1 cm were measured. The AGB for all trees with dbh ≥ 10 cm was estimated by allometric models. In order to analyze changes in the diameter-dependent parameters used for estimating the AGB, different quadrat areas, ranging from 10 m × 10 m to 60 m × 60 m, were used across the study area, starting at the South-West end and moving towards the North-East end. The derived result was as follows: (a) Big trees (dbh ≥ 70 cm) with sparse distribution have remarkable contribution to the total AGB in Bruneian lowland MDF, and therefore, special consideration is required when estimating the AGB of big trees. Stem number of trees with dbh ≥ 70 cm comprised only 2.7% of all trees with dbh ≥ 10 cm, but 38.5% of the total AGB. (b) For estimating the AGB of big trees at the given acceptable limit of precision (p), it is more efficient to use large quadrats than to use small quadrats, because the total sampling area decreases with the former. Our result showed that 239 20 m × 20 m quadrats (9.6 ha in total) were required, while 15 60 m × 60 m quadrats (5.4 ha in total) were required when estimating the AGB of the trees

  14. Population history, phylogeography, and conservation genetics of the last Neotropical mega-herbivore, the lowland tapir (Tapirus terrestris)

    PubMed Central

    2010-01-01

    Background Understanding the forces that shaped Neotropical diversity is central issue to explain tropical biodiversity and inform conservation action; yet few studies have examined large, widespread species. Lowland tapir (Tapirus terrrestris, Perissodactyla, Tapiridae) is the largest Neotropical herbivore whose ancestors arrived in South America during the Great American Biotic Interchange. A Pleistocene diversification is inferred for the genus Tapirus from the fossil record, but only two species survived the Pleistocene megafauna extinction. Here, we investigate the history of lowland tapir as revealed by variation at the mitochondrial gene Cytochrome b, compare it to the fossil data, and explore mechanisms that could have shaped the observed structure of current populations. Results Separate methodological approaches found mutually exclusive divergence times for lowland tapir, either in the late or in the early Pleistocene, although a late Pleistocene divergence is more in tune with the fossil record. Bayesian analysis favored mountain tapir (T. pinchaque) paraphyly in relation to lowland tapir over reciprocal monophyly, corroborating the inferences from the fossil data these species are sister taxa. A coalescent-based analysis rejected a null hypothesis of allopatric divergence, suggesting a complex history. Based on the geographic distribution of haplotypes we propose (i) a central role for western Amazonia in tapir diversification, with a key role of the ecological gradient along the transition between Andean subcloud forests and Amazon lowland forest, and (ii) that the Amazon river acted as an barrier to gene flow. Finally, the branching patterns and estimates based on nucleotide diversity indicate a population expansion after the Last Glacial Maximum. Conclusions This study is the first examining lowland tapir phylogeography. Climatic events at the end of the Pleistocene, parapatric speciation, divergence along the Andean foothill, and role of the Amazon

  15. The roots of future rice harvests.

    PubMed

    Ahmadi, Nourollah; Audebert, Alain; Bennett, Malcolm J; Bishopp, Anthony; de Oliveira, Antonio Costa; Courtois, Brigitte; Diedhiou, Abdala; Diévart, Anne; Gantet, Pascal; Ghesquière, Alain; Guiderdoni, Emmanuel; Henry, Amelia; Inukai, Yoshiaki; Kochian, Leon; Laplaze, Laurent; Lucas, Mikael; Luu, Doan Trung; Manneh, Baboucarr; Mo, Xiaorong; Muthurajan, Raveendran; Périn, Christophe; Price, Adam; Robin, Sabariappan; Sentenac, Hervé; Sine, Bassirou; Uga, Yusaku; Véry, Anne Aliénor; Wissuwa, Matthias; Wu, Ping; Xu, Jian

    2014-12-01

    Rice production faces the challenge to be enhanced by 50% by year 2030 to meet the growth of the population in rice-eating countries. Whereas yield of cereal crops tend to reach plateaus and a yield is likely to be deeply affected by climate instability and resource scarcity in the coming decades, building rice cultivars harboring root systems that can maintain performance by capturing water and nutrient resources unevenly distributed is a major breeding target. Taking advantage of gathering a community of rice root biologists in a Global Rice Science Partnership workshop held in Montpellier, France, we present here the recent progresses accomplished in this area and focal points where an international network of laboratories should direct their efforts. PMID:26224558

  16. Understanding of evolutionary genomics of invasive species of rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red rice is an aggressive, weedy form of cultivated rice (Oryza sativa) that infests crop fields and is a primary factor limiting rice productivity in the U.S. and worldwide. As the weedy relative of a genomic model species, red rice is a model for understanding the genetic and evolutionary mechani...

  17. Elucidation of molecular dynamics of invasive species of rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivated rice fields are aggressively invaded by weedy rice in the U.S. and worldwide. Weedy rice results in loss of yield and seed contamination. The molecular dynamics of the evolutionary adaptive traits of weedy rice are not fully understood. To understand the molecular basis and identify the i...

  18. Nitrogen fertilization on center pivot sprinkler irrigated rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three rice (Oryza sativa) experiments were conducted to determine the effects of nitrogen (N) form and timing of application on growth and yield of sprinkler irrigated rice compared to flood irrigated rice. Three rice cultivars (two conventional, one hybrid) were grown under a center pivot irrigatio...

  19. 21 CFR 172.890 - Rice bran wax.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Rice bran wax. 172.890 Section 172.890 Food and... Multipurpose Additives § 172.890 Rice bran wax. Rice bran wax may be safely used in food in accordance with the following conditions: (a) It is the refined wax obtained from rice bran and meets the...

  20. 21 CFR 172.890 - Rice bran wax.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Rice bran wax. 172.890 Section 172.890 Food and... Multipurpose Additives § 172.890 Rice bran wax. Rice bran wax may be safely used in food in accordance with the following conditions: (a) It is the refined wax obtained from rice bran and meets the...

  1. Agronomic potential of southern rice cultivars under organic management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic rice production is expanding in the United States as a result of increasing market demand. Although acreage of conventional produced rice has declined in Texas over the last twenty years, organic rice production has increased to almost ten percent of the Texas rice acreage. Organic growers ...

  2. Modification of physical properties of freeze-dried rice

    NASA Technical Reports Server (NTRS)

    Huber, C. S.

    1971-01-01

    Freeze cycling process consists of alternately freezing and thawing precooked rice for two cycles, rice is then frozen and freeze-dehydrated in vacuum sufficient to remove water from rice by sublimitation. Process modifies rice grain structure and porosity, enabling complete rehydration in one minute in hot water.

  3. 7 CFR 868.201 - Definition of rough rice.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Definition of rough rice. 868.201 Section 868.201... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Rough Rice Terms Defined § 868.201 Definition of rough rice. Rice (Oryza sativa L.) which consists of 50 percent or more of paddy kernels...

  4. 7 CFR 868.301 - Definition of milled rice.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Definition of milled rice. 868.301 Section 868.301... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Milled Rice Terms Defined § 868.301 Definition of milled rice. Whole or broken kernels of rice (Oryza sativa L.) from which the hulls and...

  5. 7 CFR 868.301 - Definition of milled rice.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Definition of milled rice. 868.301 Section 868.301... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Milled Rice Terms Defined § 868.301 Definition of milled rice. Whole or broken kernels of rice (Oryza sativa L.) from which the hulls and...

  6. 7 CFR 868.201 - Definition of rough rice.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Definition of rough rice. 868.201 Section 868.201... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Rough Rice Terms Defined § 868.201 Definition of rough rice. Rice (Oryza sativa L.) which consists of 50 percent or more of paddy kernels...

  7. 7 CFR 868.201 - Definition of rough rice.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Definition of rough rice. 868.201 Section 868.201... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Rough Rice Terms Defined § 868.201 Definition of rough rice. Rice (Oryza sativa L.) which consists of 50 percent or more of paddy kernels...

  8. 7 CFR 868.301 - Definition of milled rice.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Definition of milled rice. 868.301 Section 868.301... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Milled Rice Terms Defined § 868.301 Definition of milled rice. Whole or broken kernels of rice (Oryza sativa L.) from which the hulls and...

  9. 7 CFR 868.201 - Definition of rough rice.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Definition of rough rice. 868.201 Section 868.201... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Rough Rice Terms Defined § 868.201 Definition of rough rice. Rice (Oryza sativa L.) which consists of 50 percent or more of paddy kernels...

  10. 7 CFR 868.301 - Definition of milled rice.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Definition of milled rice. 868.301 Section 868.301... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Milled Rice Terms Defined § 868.301 Definition of milled rice. Whole or broken kernels of rice (Oryza sativa L.) from which the hulls and...

  11. 21 CFR 172.890 - Rice bran wax.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Rice bran wax. 172.890 Section 172.890 Food and... Multipurpose Additives § 172.890 Rice bran wax. Rice bran wax may be safely used in food in accordance with the following conditions: (a) It is the refined wax obtained from rice bran and meets the...

  12. 7 CFR 868.201 - Definition of rough rice.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Definition of rough rice. 868.201 Section 868.201... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Rough Rice Terms Defined § 868.201 Definition of rough rice. Rice (Oryza sativa L.) which consists of 50 percent or more of paddy kernels...

  13. 7 CFR 868.301 - Definition of milled rice.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Definition of milled rice. 868.301 Section 868.301... FOR CERTAIN AGRICULTURAL COMMODITIES United States Standards for Milled Rice Terms Defined § 868.301 Definition of milled rice. Whole or broken kernels of rice (Oryza sativa L.) from which the hulls and...

  14. 21 CFR 172.890 - Rice bran wax.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Rice bran wax. 172.890 Section 172.890 Food and... Multipurpose Additives § 172.890 Rice bran wax. Rice bran wax may be safely used in food in accordance with the following conditions: (a) It is the refined wax obtained from rice bran and meets the...

  15. Rice Bran: Production, Composition, Functionality and Food Applications, Physiological Benefits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal and human studies show cholesterol-lowering with rice bran in hypercholesterolemic individuals. Specific rice bran fractions showing hypocholesterolemic activity include rice bran oil, unsaponifiable matter, dietary fiber and protein. There is a dose response to the level of rice bran and r...

  16. Identifying novel resistance genes in rice wild relatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast and sheath blight are major fungal diseases of cultivated rice (Oryza sativa L. ) that limit Arkansas rough rice yields and market potential. Resistance to these diseases has been found in rice wild relatives (Oryza spp.) A collection of these wild relatives originating from outside the U...

  17. Identification of Some Degradation Products of Golden Rice Beta- carotene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Golden Rice (GR2) is genetically modified rice, which can contain as high as 37 ug of beta-carotene per g of dry rice. It was developed to combat vitamin A deficiency (VAD), a major malnutrition problem in many parts of the developing world, especially in South and South Eastern Asia, where rice is ...

  18. Analysis of genotypic diversity in esterase activity of rice bran

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice bran is a by-product of the rice milling process. It is rich in protein, fat, crude fiber, minerals and vitamins, and is a valuable source of antioxidants. It can be used for ingredients, be developed into a functional food, and can be extracted for rice bran oil production. However, rice bran ...

  19. Utilization of trait-linked DNA markers in rice breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    DNA marker technology is being used in U.S. rice breeding programs to enhance development of rice cultivars with improved cooking quality and genetic resistance to rice blast disease. Because there is a continuous threat of race shifts within the Magnaporthe grisea populations found in rice fields t...

  20. Golden Rice is an effective source for vitamin A

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetically engineered "Golden Rice" contains up to 35 ug Beta-carotene per gram of rice. It is important to determine the vitamin A equivalency of Golden Rice Beta-carotene to project the potential effect of this biofortified grain in rice-consuming populations that commonly exhibit low vitamin A s...