Science.gov

Sample records for agricultural growing seasons

  1. The Effect of Agricultural Growing Season Change on Market Prices in Africa

    NASA Technical Reports Server (NTRS)

    deBeurs, K.M.; Brown, M. E.

    2013-01-01

    Local agricultural production is a key element of food security in many agricultural countries in Africa. Climate change and variability is likely to adversely affect these countries, particularly as they affect the ability of smallholder farmers to raise enough food to feed themselves. Seasonality influences farmers' decisions about when to sow and harvest, and ultimately the success or failure of their crops. At a 2009 conference in the United Kingdom hosted by the Institute of Development Studies, Jennings and Magrath (2009) described farmer reports from East Asia, South Asia, Southern Africa, East Africa and Latin America. Farmers indicate significant changes in the timing of rainy seasons and the pattern of rains within seasons, including: More erratic rainfall, coming at unexpected times in and out of season; Extreme storms and unusually intense rainfall are punctuated by longer dry spells within the rainy season; Increasing uncertainty as to the start of rainy seasons in many areas; Short or transitional second rainy seasons are becoming stronger than normal or are disappearing altogether. These farmer perceptions of change are striking in that they are geographically widespread and are remarkably consistent across diverse regions (Jennings and Magrath, 2009). The impact of these changes on farmers with small plots and few resources is large. Farming is becoming riskier because of heat stress, lack of water, pests and diseases that interact with ongoing pressures on natural resources. Lack of predictability in the start and length of the growing season affects the ability of farmers to invest in appropriate fertilizer levels or improved, high yielding varieties. These changes occur at the same time as the demand for food is rising and is projected to continue to rise for the next fifty years (IAASTD, 2008). Long-term data records derived from satellite remote sensing can be used to verify these reports, providing necessary analysis and documentation required

  2. Rainfall-derived growing season characteristics for agricultural impact assessments in South Africa

    NASA Astrophysics Data System (ADS)

    Ambrosino, Chiara; Chandler, Richard E.; Todd, Martin C.

    2014-02-01

    Precipitation variability imposes significant pressure in areas where agricultural practice is dominated by smallholder farmers who are dependent on subsistence farming. Advances in the understanding of this variability, in both time and space, have an important role to play in increasing the resilience of agricultural systems. The need is particularly pressing in regions of the world such as the African continent, which is already affected by multiple stresses including poverty and economic and political instability. In this paper, we explore the use of generalised linear models (GLMs) for this purpose, via a case study from north-east South Africa. A GLM is used to link the local rainfall variability to large-scale climate drivers identified from previous subcontinental-scale analyses, and the ability of the resulting model to simulate precipitation features that are relevant in agricultural applications is evaluated. We focus in particular on a set of growing season indices, proposed for the investigation of intraseasonal characteristics relevant for maize production in the region. Seven indices were computed from spatially averaged daily rainfall series from nine stations in the study area. As a first attempt to use GLMs for this type of application, the results are encouraging and suggest that the models are able to reproduce a range of agriculture-relevant indices. However, further research into spatial correlation structure is recommended to improve the multisite generation of the rainfall-derived characteristics.

  3. Temporal variability of atmospheric particulate matter and chemical composition during a growing season at an agricultural site in northeastern China.

    PubMed

    Chen, Weiwei; Tong, Daniel; Zhang, Shichun; Dan, Mo; Zhang, Xuelei; Zhao, Hongmei

    2015-12-01

    This study presents the observations of PM10 and PM2.5 concentrations at an agricultural site from April to October 2012 in Dehui city, China. Ambient air was sampled by filter-based samplers and online PM monitors. The filter samples were analyzed to determine the abundance of ionic/inorganic elements, organic carbon (OC) and elemental carbon (EC). The daily PM10 concentrations varied significantly over the monitoring period, with an average of 168±63 (in the range of 52-277)μg/m(3) during the land preparation/planting period (26 April-15 June), 85±65 (36-228)μg/m(3) during the growing season (16 June-25 September), and 207±88 (103-310)μg/m(3) during the harvest period (26 September-31 October). PM2.5 accounted for 44%, 56% and 66% of atmospheric PM10 during these periods, respectively. The PM10 diurnal variation showed a distinct peak from 16:00 to 21:00 (LST) during the growing and harvesting seasons, while a gradual increase throughout the daytime until 17:00 was observed during tilling season. Mineral dust elements (Al, Ca, Fe, and Mg) dominated the PM10 chemical composition during the tilling season; OC, NO3(-), SO4(2-) and NH4(+) during the growing season; and carbonaceous species (i.e., OC and EC) during the harvesting season. Our results indicate that the soil particles emitted by farm tillage and organic matter released from straw burning are the two most significant sources of PM10 emissions contributing to the recurring high pollution events in this region. Therefore, development of agricultural PM inventories from soil tillage and straw burning is prioritized to support air quality modeling. PMID:26702977

  4. Are BVOC exchanges in agricultural ecosystems overestimated? Insights from fluxes measured in a maize field over a whole growing season

    NASA Astrophysics Data System (ADS)

    Bachy, Aurélie; Aubinet, Marc; Schoon, Niels; Amelynck, Crist; Bodson, Bernard; Moureaux, Christine; Heinesch, Bernard

    2016-04-01

    Although maize is the second most important crop worldwide, and the most important C4 crop, no study on biogenic volatile organic compounds (BVOCs) has yet been conducted on this crop at ecosystem scale and over a whole growing season. This has led to large uncertainties in cropland BVOC emission estimations. This paper seeks to fill this gap by presenting, for the first time, BVOC fluxes measured in a maize field at ecosystem scale (using the disjunct eddy covariance by mass scanning technique) over a whole growing season in Belgium. The maize field emitted mainly methanol, although exchanges were bi-directional. The second most exchanged compound was acetic acid, which was taken up mainly in the growing season. Bi-directional exchanges of acetaldehyde, acetone and other oxygenated VOCs also occurred, whereas the terpenes, benzene and toluene exchanges were small, albeit significant. Surprisingly, BVOC exchanges were of the same order of magnitude on bare soil and on well developed vegetation, suggesting that soil is a major BVOC reservoir in agricultural ecosystems. Quantitatively, the maize BVOC emissions observed were lower than those reported in other maize, crops and grasses studies. The standard emission factors (SEFs) estimated in this study (231 ± 19 µg m-2 h-1 for methanol, 8 ± 5 µg m-2 h-1 for isoprene and 4 ± 6 µg m-2 h-1 for monoterpenes) were also much lower than those currently used by models for C4 crops, particularly for terpenes. These results suggest that maize fields are small BVOC exchangers in north-western Europe, with a lower BVOC emission impact than that modelled for growing C4 crops in this part of the world. They also reveal the high variability in BVOC exchanges across world regions for maize and suggest that SEFs should be estimated for each region separately.

  5. Are BVOC exchanges in agricultural ecosystems overestimated? Insights from fluxes measured in a maize field over a whole growing season

    NASA Astrophysics Data System (ADS)

    Bachy, Aurélie; Aubinet, Marc; Schoon, Niels; Amelynck, Crist; Bodson, Bernard; Moureaux, Christine; Heinesch, Bernard

    2016-04-01

    Maize is the most important C4 crop worldwide. It is also the second most important crop worldwide (C3 and C4 mixed), and is a dominant crop in some world regions. Therefore, it can potentially influence local climate and air quality through its exchanges of gases with the atmosphere. Among others, biogenic volatile organic compounds (BVOC) are known to influence the atmospheric composition and thereby modify greenhouse gases lifetime and pollutant formation in the atmosphere. However, so far, only two studies have dealt with BVOC exchanges from maize. Moreover, these studies were conducted on a limited range of meteorological and phenological conditions, so that the knowledge of BVOC exchanges by this crop remains poor. Here, we present the first BVOC measurement campaign performed at ecosystem-scale on a maize field during a whole growing season. It was carried out in the Lonzée Terrestrial Observatory (LTO), an ICOS site. BVOC fluxes were measured by the disjunct by mass-scanning eddy covariance technique with a proton transfer reaction mass spectrometer for BVOC mixing ratios measurements. Outstanding results are (i) BVOC exchanges from soil were as important as BVOC exchanges from maize itself; (ii) BVOC exchanges observed on our site were much lower than exchanges observed by other maize studies, even under normalized temperature and light conditions, (iii) they were also lower than those observed on other crops grown in Europe. Lastly (iv), BVOC exchanges observed on our site under standard environmental conditions, i.e., standard emission factors SEF, were much lower than those currently considered by BVOC exchange up-scaling models. From those observations, we deduced that (i) soil BVOC exchanges should be better understood and should be incorporated in terrestrial BVOC exchanges models, and that (ii) SEF for the C4 crop plant functional type cannot be evaluated at global scale but should be determined for each important agronomic and pedo-climatic region

  6. Spatiotemporal variations in growing season exchanges of CO2, H2O,and sensible heat in agricultural fields of the Southern GreatPlains

    SciTech Connect

    Fischer, Marc L.; Billesbach, David P.; Berry, Joseph A.; Riley,William J.; Torn, Margaret S.

    2007-06-13

    Climate, vegetation cover, and management create fine-scaleheterogeneity in unirrigated agricultural regions, with important but notwell-quantified consequences for spatial and temporal variations insurface CO2, water, and heat fluxes. We measured eddy covariance fluxesin seven agricultural fields--comprising winter wheat, pasture, andsorghum--in the U.S. Southern Great Plains (SGP) during the 2001-2003growing seasons. Land-cover was the dominant source of variation insurface fluxes, with 50-100 percent differences between fields planted inwinter-spring versus fields planted in summer. Interannual variation wasdriven mainly by precipitation, which varied more than two-fold betweenyears. Peak aboveground biomass and growing-season net ecosystem exchange(NEE) of CO2 increased in rough proportion to precipitation. Based on apartitioning of gross fluxes with a regression model, ecosystemrespiration increased linearly with gross primary production, but with anoffset that increased near the time of seed production. Because theregression model was designed for well-watered periods, it successfullyretrieved NEE and ecosystem parameters during the peak growing season,and identified periods of moisture limitation during the summer. Insummary, the effects of crop type, land management, and water limitationon carbon, water, and energy fluxes were large. Capturing the controllingfactors in landscape scale models will be necessary to estimate theecological feedbacks to climate and other environmental impactsassociated with changing human needs for agricultural production of food,fiber, and energy.

  7. A complete and continuous pesticide screening during one growing season in five small Swiss rivers with agricultural watersheds

    NASA Astrophysics Data System (ADS)

    Mangold, Simon; Comte, Rahel; Doppler, Tobias; Wittmer, Irene; Moschet, Christoph; Stamm, Christian; Singer, Heinz; Kunz, Manuel

    2016-04-01

    Agricultural pesticides are regularly found in surface waters at concentration levels that raise ecotoxicological concerns. Due to large fluctuations in concentration over time and the potentially high number of pesticides in agricultural watersheds, it is difficult to obtain a comprehensive overview of the actual pollution level. This collaborative project between research and Swiss federal and cantonal authorities aimed for a comprehensive analysis of pesticide pollution in five small agricultural streams to address this knowledge gap. The five rivers are located in catchments (1.5 to 9 km2) with intensive agriculture covering a wide range of crops, such as grains, vegetables, vineyards and orchards. Urban activities and influences are low. Twelve-hour composite samples were collected continuously from March until the end of August with automatic sampling devices, resulting in 360 samples per site. Using precipitation and water level data, we differentiated between discharge events and low-flow periods. Samples taken during dry weather were pooled for the analysis. This procedure resulted in a complete concentration profile over the entire monitoring period covered by 60 samples per site. The analysis, using liquid chromatography coupled to high resolution mass spectrometry (Orbitrap technology), involved a target screening of 248 pesticides including fungicides, herbicides, insecticides, as well as important transformation products. Data on the total number and distribution of pesticides, their detection frequency, crop specific applications and concentration time profiles will be presented. Preliminary results indicate substantial pesticide exposure since at least 20 different compounds were detected in all samples. One sample even contained a mixture of 80 pesticides. The majority of concentrations were in the low ng/L range but concentrations of a few compounds were very high (several micrograms/L) during discharge events as well as during low flow conditions

  8. Environmental and societal consequences of a possible CO/sub 2/-induced climate change. Volume II, Part 8. Impacts of rising atmospheric carbon dioxide levels on agricultural growing seasons and crop water use efficiencies

    SciTech Connect

    Newman, J. E.

    1982-09-01

    The researchable areas addressed relate to the possible impacts of climate change on agricultural growing seasons and crop adaptation responses on a global basis. The research activities proposed are divided into the following two main areas of investigation: anticipated climate change impacts on the physical environmental characteristics of the agricultural growing seasons and, the most probable food crop responses to the possible changes in atmospheric CO/sub 2/ levels in plant environments. The main physical environmental impacts considered are the changes in temperature, or more directly, thermal energy levels and the growing season evapotranspiration-precipitation balances. The resulting food crop, commercial forest and rangeland species response impacts addressed relate to potential geographical shifts in agricultural growing seasons as determined by the length in days of the frost free period, thermal energy changes and water balance changes. In addition, the interaction of possible changes in plant water use efficiencies during the growing season in relationship to changing atmospheric CO/sub 2/ concentrations, is also considered under the scenario of global warming due to increases in atmospheric CO/sub 2/ concentration. These proposed research investigations are followed by adaptive response evaluations.

  9. Impact of Seasonal Forecasts on Agriculture

    NASA Astrophysics Data System (ADS)

    Aldor-Noiman, S. C.

    2014-12-01

    More extreme and volatile weather conditions are a threat to U.S. agricultural productivity today, as multiple environmental conditions during the growing season impact crop yields. That's why farmers' agronomic management decisions are dominated by consideration for near, medium and seasonal forecasts of climate. The Climate Corporation aims to help farmers around the world protect and improve their farming operations by providing agronomic decision support tools that leverage forecasts on multiple timescales to provide valuable insights directly to farmers. In this talk, we will discuss the impact of accurate seasonal forecasts on major decisions growers face each season. We will also discuss assessment and evaluation of seasonal forecasts in the context of agricultural applications.

  10. Projected changes in Malawi's growing season

    NASA Astrophysics Data System (ADS)

    Vizy, Edward K.; Cook, Kerry H.; Chimphamba, James; McCusker, Brent

    2015-09-01

    Regional climate model projections at 30-km resolution are used to predict future mid-century and late-century growing season changes over Malawi due to global warming under the Representative Concentration Pathway 8.5 business-as-usual emissions forcing scenario. Three different methods for estimating growing season characteristics are applied and evaluated. All three methods yield reasonable growing season length, onset, and demise date estimates over Malawi given the wide range of uncertainty of the observations. The projections indicate the likelihood for a shorter growing season in the future over Malawi south of 13.5°S. At mid-century the growing season length is predicted to be 20-40 % (20-55 days) shorter over the southernmost districts and 5-20 % (5-30 days) shorter over the central districts. By late-century the length is predicted to be 25-55 % (20-70 days) shorter with significant differences extending into northern Malawi. The shorter growing season is primarily associated with an earlier demise date, as no significant change in the onset date is predicted. Analysis of the regional circulation and horizontal moisture flux transport indicates that the earlier demise is associated with an intensification of the thermal low over the Kalahari Desert to the south and west of Malawi and an expansion of the mid-tropospheric Kalahari anticyclone over southern Africa. The stronger thermal low/anticyclone enhances the moisture flux divergence over Malawi suppressing the convective activity at the end of the wet season.

  11. Seasonal Agricultural Labor in Oregon.

    ERIC Educational Resources Information Center

    Oregon State Univ., Corvallis.

    Requested by the governor of Oregon, this 1968 report focuses on seasonal agricultural labor in Oregon. The task force, appointed by the president of Oregon State University, reported on the following areas: (1) the problem in terms of potential unionization, population trends, existing state programs and agencies for the migrants; (2) regulations…

  12. Growing season precipitation in Finland under recent and projected climate

    NASA Astrophysics Data System (ADS)

    Ylhäisi, J. S.; Tietäväinen, , H.; Peltonen-Sainio, P.; Venäläinen, A.; Eklund, J.; Räisänen, J.; Jylhä, K.

    2010-07-01

    The past and projected future precipitation sum in May-September for two areas in Finland, one located in the south-west (SW) and the other in the north-east (NE), is studied using 13 regional climate simulations and three observational datasets. The conditions in the present-day climate for agricultural crop production are far more favourable in the south-western part of the country than the more continental north-eastern Finland. Based on a new high-resolution observational precipitation dataset for Finland (FMI_grid), with a resolution of 10×10 km, the only statistically significant past long-term (1908-2008) precipitation tendencies in the two study regions are positive. Differences between FMI_grid and two other observational datasets during 1961-2000 are rather large in the NE, whereas in the SW the datasets agree better. Observational uncertainties stem from the interpolation and sampling errors. The projected increases in precipitation in the early stage of the growing season would be most favourable for agricultural productivity, but the projected increases in August and September might be harmful. Model projections for the future indicate a statistically significant increase in precipitation for most of the growing season by 2100, but the distribution of precipitation within the growing season is not necessarily the most optimal.

  13. Monitoring and modeling growing season dynamics

    NASA Astrophysics Data System (ADS)

    White, Michael Aaron

    Phenology, the study of recurring biological cycles and their connection to climate, is a growing field of global change research. Vegetation phenology exerts a strong control over carbon cycles, weather, and global radiation partitioning between sensible and latent heat fluxes. Phenological monitors of the timing and length of the growing season can also be used as barometers of vegetation responses to climatic variability. In the following chapters, I present research investigating the monitoring and interpretation of growing season dynamics. Ecological modeling is limited more by data availability than by model theory. In particular, the description of vegetation functional types (biomes) for distributed modeling has been lacking. In chapter 1, I present a documented description and sensitivity analysis of the 34 parameters used in the ecosystem model, BIOME-BGC, for major temperate biomes. I applied BIOME-BGC in the eastern U.S. deciduous broad leaf forest and found that minor phenological variation created large impacts on simulated net ecosystem exchange of carbon (chapter 2). In addition to simulating the effects of growing season variability, it is also important to develop accurate field monitoring techniques, both as a means of testing modeling activities and as a validation of satellite remote sensing estimates. I conducted an intercomparison of field techniques that could be used to monitor phenological dynamics in and ecosystems (chapter 3). I found that methodological barriers to rapid, low cost monitoring were severe, but that a digital camera with both visible and near-infrared channels was a viable option. Satellite remote sensing provides the only means of obtaining consistent estimates of phenological variation at a global scale, yet our understanding of these data has been limited by a lack of ground observations. To address this problem, I proposed, developed, and wrote a phenology measurement protocol for the Global Learning and Observations

  14. Monitoring Southern African Rainfall Season Utilizing Growing Regions

    NASA Astrophysics Data System (ADS)

    Husak, G. J.; Magadzire, T.

    2005-12-01

    Variability in timing and amount of rainfall during the growing season in southern Africa can have a dramatic impact on livelihoods in the region. This research integrates satellite model rainfall amounts with expectations for the remainder of the season to provide an envelope of likely outcomes for different growing regions. Satellite information combined with station observations combine to make the African Rainfall Climatology (ARC), which is used to estimate the start of season (SOS) and monitor the season-to-date rainfall accumulations at a pixel level. The Collaborative Historical African Rainfall Model (CHARM) - a 36-year climatology based on available station fields, global climate models and an orographic component - is used to estimate various scenarios for the remainder of the season. The season length is defined by location specific length of growing period provided by the Southern African Development Community (SADC). Once the SOS is observed according to the ARC, seasonal accumulations for each pixel begin and are evaluated at a dekadal interval. These accumulations can be compared to historical accumulations after an equal number of dekads to evaluate the progression of the season as a percentage of historical season-to-date totals for each pixel. Rainfall accumulations for the remainder of the growing period can be tallied for each year of the CHARM dataset, and Gamma probability distribution parameters can be fit to these values. Using these distribution parameters, it is possible to evaluate scenarios for the remainder of the season and combine them with the accumulations from the ARC to arrive at total rainfall accumulated during a growing period. Analysis of these totals can be compared with long-term mean accumulations for the growing period to estimate how crops will fare relative to past performance. Evaluation of various wet and dry scenarios for the remainder of the season, defined here as the 80th percentile and 20th percentile, provide an

  15. AGRICULTURAL SEASONAL LABORERS OF COLORADO AND CALIFORNIA.

    ERIC Educational Resources Information Center

    KARRAKER, CYRUS H.

    ACCOMPLISHMENTS IN THE WELFARE OF AGRICULTURAL SEASONAL WORKERS ARE REPORTED. PARTICULAR ATTENTION IS PAID TO SUCH SERVICES FOR MIGRANT CHILDREN AS DAY CARE CENTERS. SUCH CENTERS ARE PROVIDED FROM PRIVATE FUNDS, ARE USUALLY CHURCH SPONSORED, AND ARE LARGELY STAFFED BY VOLUNTEERS. STATE-OPERATED CENTERS ARE RECOMMENDED. COLORADO WAS CONE OF THE…

  16. Growing Season Evapotranspiration with Satellite Remote Sensing Procedure

    NASA Astrophysics Data System (ADS)

    Irmak, A.; Ratcliffe, I.; Ranade, P.; Kamble, B.; Mutiibwa, D.; Akasheh, O. Z.; Hydrologic Information System Team

    2010-12-01

    Water is the most important constraint facing agriculture in the most of the Central High Plains of the U.S.A.. Local, state and federal water management regulatory agencies need good quality water use estimates by different land surfaces to assess short and long-term water management, planning, and allocations on a watershed scale. Evapotranspiration (ET) can be defined as the loss of water from the ground, lake or pond, and vegetative surfaces to the atmosphere through vaporization of liquid water. The ability is required to accurately estimate the magnitude of this flux will, therefore, go a long way towards being able to compute the water balance and plan the water resources and regimes.. Furthermore, quantification of this flux on a watershed or a regional scale is much more difficult. In this study we applied the Mapping Evapotranspiration at High Resolution with internal calibration (METRIC) to obtain ET maps for Central and Western parts of Nebraska. Landsat 5 and Landsat 7 images were processed for the 2005 and 2007 growing seasons to obtain instantaneous and daily ET. Monthly and Seasonal ET data are rarely presented in previous studies and are often required for quantifying water consumption. In order to produce monthly and seasonal ET maps, individual daily ET maps generated from METRIC were interpolated between dates on a daily basis using a cubic-spline model. Cloud artifacts were removed and filled back in using interpolated ET data and a daily background evaporation adjustment based on the FAO-56 Ke evaporation model. The maps generated by the METRICtm allowed us to follow the seasonal trend in evaporative faction and ET for major land use classes. If calibrated properly, the model could be a viable tool to estimate water use in managed and native ecosystems in sub-humid climates at a large scale. The METRICtm approach presented in this paper illustrated how an ‘off-the-shelf’ model can be applied operationally over a significant time period and

  17. Elevated CO2 further lengthens growing season under warming conditions.

    PubMed

    Reyes-Fox, Melissa; Steltzer, Heidi; Trlica, M J; McMaster, Gregory S; Andales, Allan A; LeCain, Dan R; Morgan, Jack A

    2014-06-12

    Observations of a longer growing season through earlier plant growth in temperate to polar regions have been thought to be a response to climate warming. However, data from experimental warming studies indicate that many species that initiate leaf growth and flowering earlier also reach seed maturation and senesce earlier, shortening their active and reproductive periods. A conceptual model to explain this apparent contradiction, and an analysis of the effect of elevated CO2--which can delay annual life cycle events--on changing season length, have not been tested. Here we show that experimental warming in a temperate grassland led to a longer growing season through earlier leaf emergence by the first species to leaf, often a grass, and constant or delayed senescence by other species that were the last to senesce, supporting the conceptual model. Elevated CO2 further extended growing, but not reproductive, season length in the warmed grassland by conserving water, which enabled most species to remain active longer. Our results suggest that a longer growing season, especially in years or biomes where water is a limiting factor, is not due to warming alone, but also to higher atmospheric CO2 concentrations that extend the active period of plant annual life cycles. PMID:24759322

  18. New satellite-based maps of the growing season north of 50°N

    NASA Astrophysics Data System (ADS)

    Rune Karlsen, Stein; Arild Høgda, Kjell; Tolvanen, Anne; Johansen, Bernt; Elvebakk, Arve

    2009-09-01

    In this study we present new satellite-based maps of the growing season of northern areas. The maps show trends and mean date in onset and length of the growing season at different scales north of 50° N. For all the circumpolar area we use the GIMMS-NDVI satellite dataset for the 1982 to 2006 period, and for the Nordic countries we used the MODISNDVI satellite data for the 2000 to 2007 period. The circumpolar maps are not as accurate as the one covering the Nordic countries, this due to lack of ancillary environmental geo-data available that can be included in the mapping process. In particular this is a problem for the Russian part of the circumpolar north. The resulting growing season maps are useful in a broad range of ecological and climatic changes studies. Changes in the timing of the growing season are sensitive bio-indicators of climate change of northern areas, and these changes crucially affects primary industries, such as agriculture, animal husbandry and forestry, as well as the population dynamics of wild mammals and birds. The onset of growing season maps is also useful to improve pollen forecasts, and the maps can be used to improve the global change models.

  19. New satellite-based maps of the growing season north of 50°N

    NASA Astrophysics Data System (ADS)

    Rune Karlsen, Stein; Arild Høgda, Kjell; Tolvanen, Anne; Johansen, Bernt; Elvebakk, Arve

    2010-11-01

    In this study we present new satellite-based maps of the growing season of northern areas. The maps show trends and mean date in onset and length of the growing season at different scales north of 50° N. For all the circumpolar area we use the GIMMS-NDVI satellite dataset for the 1982 to 2006 period, and for the Nordic countries we used the MODISNDVI satellite data for the 2000 to 2007 period. The circumpolar maps are not as accurate as the one covering the Nordic countries, this due to lack of ancillary environmental geo-data available that can be included in the mapping process. In particular this is a problem for the Russian part of the circumpolar north. The resulting growing season maps are useful in a broad range of ecological and climatic changes studies. Changes in the timing of the growing season are sensitive bio-indicators of climate change of northern areas, and these changes crucially affects primary industries, such as agriculture, animal husbandry and forestry, as well as the population dynamics of wild mammals and birds. The onset of growing season maps is also useful to improve pollen forecasts, and the maps can be used to improve the global change models.

  20. Seasonal Climate Forecasts and Adoption by Agriculture

    NASA Astrophysics Data System (ADS)

    Garbrecht, Jurgen; Meinke, Holger; Sivakumar, Mannava V. K.; Motha, Raymond P.; Salinger, Michael J.

    2005-06-01

    Recent advances in atmospheric and ocean sciences and a better understanding of the global climate have led to skillful climate forecasts at seasonal to interannual timescales, even in midlatitudes. These scientific advances and forecasting capabilities have opened the door to practical applications that benefit society. The benefits include the reduction of weather/climate related risks and vulnerability, increased economic opportunities, enhanced food security, mitigation of adverse climate impacts, protection of environmental quality, and so forth. Agriculture in particular can benefit substantially from accurate long-lead seasonal climate forecasts. Indeed, agricultural production very much depends on weather, climate, and water availability, and unexpected departures from anticipated climate conditions can thwart the best laid management plans. Timely climate forecasts offer means to reduce losses in drought years, increase profitability in good years, deal more effectively with climate variability, and choose from targeted risk-management strategies. In addition to benefiting farmers, forecasts can also help marketing systems and downstream users prepare for anticipated production outcomes and associated consequences.

  1. Photosynthetic Control of Atmospheric Carbonyl Sulfide during the Growing Season

    NASA Technical Reports Server (NTRS)

    Campbell, J. Elliott; Carmichael, Gregory R.; Chai, T.; Mena-Carrasco, M.; Tang, Y.; Blake, D. R.; Blake, N. J.; Vay, Stephanie A.; Collatz, G. James; Baker, I.; Berry, J. A.; Montzka, S. A.; Sweeney, C.; Schnoor, J. L.; Stanier, Charles O.

    2008-01-01

    Climate models incorporate photosynthesis-climate feedbacks, yet we lack robust tools for large-scale assessments of these processes. Recent work suggests that carbonyl sulfide (COS), a trace gas consumed by plants, could provide a valuable constraint on photosynthesis. Here we analyze airborne observations of COS and carbon dioxide concentrations during the growing season over North America with a three-dimensional atmospheric transport model. We successfully modeled the persistent vertical drawdown of atmospheric COS using the quantitative relation between COS and photosynthesis that has been measured in plant chamber experiments. Furthermore, this drawdown is driven by plant uptake rather than other continental and oceanic fluxes in the model. These results provide quantitative evidence that COS gradients in the continental growing season may have broad use as a measurement-based photosynthesis tracer.

  2. Pollutants dynamics in a rice field catchment during storms in the growing and non-growing seasons

    NASA Astrophysics Data System (ADS)

    Kim, J. S.; Lee, J. B.; Cho, J. P.

    2012-04-01

    We compared the behavior of pollutants such as total nitrogen (TN), total phosphorous (TP), chemical oxygen demand (COD) and suspended solid (SS) in runoff from a Korean rice field catchment during storm events between growing and non-growing seasons. The study catchment has a size of 21.9 ha and its water source is river. Fertilizers were applied at rates of 91 N kg ha-1 and 18 P kg ha-1 as basal and top dressings. The rice fields are shallowly (3-10 cm) flooded during most of the growing season, and therefore runoff water always flows during the growing season but flows only during storms in the non-growing season. TN concentrations in runoff water decreased with discharge irrespective of the season, whereas TP, COD and SS concentrations increased with discharge. Event mean concentrations (EMCs) of pollutants in runoff water from the catchment during the non-growing season were 2 to 3 times higher than those during the growing season. This may be because flooded water in the growing season greatly reduces transport of pollutant associated with soil erosion. The results suggest that the rice field catchment may act as a sink of some pollutants during growing season but as a source of all pollutants during non-growing season. .

  3. Inter-annual Variation in Growing Season Length of a Tropical Seasonal Forest in Northern Thailand

    NASA Astrophysics Data System (ADS)

    Yoshifuji, N.; Tanaka, N.; Suzuki, M.; Tantasirin, C.

    2007-12-01

    Growing season length is an important factor affecting energy balance and water and carbon cycling at deciduous forests. The impact of its inter-annual variation on annual energy and carbon exchange is likely to be critical especially in tropical region because of high radiant energy throughout the year; however, few studies investigated inter-annual variation in growing season length of tropical deciduous forests. This study revealed year-to-year variations in the canopy duration and transpiration period as measures of growing season length using time series data of radiative transmittance and heat pulse velocities of canopy trees in a teak plantation in northern Thailand from 2001 to 2006. This study also examined whether year-to-year variation in growing season revealed by field measurements could be detected by satellite NDVI data, as a first step to investigate the inter- annual variation in growing season length of deciduous forests over tropical monsoon region. Leaf-out and transpiration commenced earlier in 2001 than other years following exceptionally heavy rainfall in the late dry season, suggesting that enhanced soil moisture advanced leaf unfolding and start of transpiration. Leaf-fall and decline in transpiration at the beginning of 2003 were late in coming in correlation with a prolonged rainy season. Declines in transpiration were directly controlled by soil moisture at the beginning of the dry season. These results revealed that soil moisture is a major cause of large inter-annual variation in the growing season at this site. Seasonal variation in NDVI corresponded to that of LAI, while transpiration declined earlier than LAI and NDVI in the dry season. Year-to-year variation in canopy duration could be also detected by NDVI. The variation in canopy duration and transpiration period of this site from 2001-2006 spanned about 60 days. This was much larger than the inter-annual variations previously reported in temperate deciduous forests, implying a

  4. Rainfall and the length of the growing season in Nigeria

    NASA Astrophysics Data System (ADS)

    Odekunle, T. O.

    2004-03-01

    This study examines the length of the growing season in Nigeria using the daily rainfall data of Ikeja, Ondo, Ilorin, Kaduna and Kano. The data were collected from the archives of the Nigerian Meteorological Services, Oshodi, Lagos. The length of the growing season was determined using the cumulative percentage mean rainfall and daily rainfall probability methods.Although rainfall in Ikeja, Ondo, Ilorin, Kaduna, and Kano appears to commence around the end of the second dekad of March, middle of the third dekad of March, mid April, end of the first dekad of May, and early June respectively, its distribution characteristics at the respective stations remain inadequate for crop germination, establishment, and development till the end of the second dekad of May, early third dekad of May, mid third dekad of May, end of May, and end of the first dekad of July respectively. Also, rainfall at the various stations appears to retreat starting from the early third dekad of October, early third dekad of October, end of the first dekad of October, end of September, and early second dekad of September respectively, but its distribution characteristics only remain adequate for crop development at the respective stations till around the end of the second dekad of October, end of the second dekad of October, middle of the first dekad of October, early October, and middle of the first dekad of September respectively. Thus, the active lengths of the growing season are approximately 5 months, 5 months, 4 months, 4 months, and 2 months respectively. Plants that are short-dry-spell tolerant may thrive early in the rainy season, i.e. from the end of the second dekad of March to the end of the second dekad of May (in Ikeja), middle of the third dekad of March to the early third dekad of May (in Ondo), mid April to the middle of the third dekad of May (in Ilorin), end of the first dekad of May to end of May (in Kaduna), and early June to the end of the first dekad in July (in Kano), but

  5. Intra-seasonal rainfall variability during the maize growing season in the northern lowlands of Lesotho

    NASA Astrophysics Data System (ADS)

    Tongwane, Mphethe Isaac; Moeletsi, Mokhele Edmond

    2015-05-01

    Intra-seasonal rainfall distribution was identified as a priority gap that needs to be addressed for southern Africa to cope with agro-meteorological risks. The region in the northwest of Lesotho is appropriate for crop cultivation due to its relatively favourable climatic conditions and soils. High rainfall variability is often blamed for poor agricultural production in this region. This study aims to determine the onset of rains, cessation of rains and rainy season duration using historical climate data. Temporal variability of these rainy season characteristics was also investigated. The earliest and latest onset dates of the rainy season are during the last week of October at Butha-Buthe and the third week of November at Mapoteng, respectively. Cessation of the season is predominantly in the first week of April making the season approximately 137-163 days long depending on the location. Average seasonal rainfall ranged from 474 mm at Mapoteng to 668 mm at Butha-Buthe. Onset and cessation of the rainfall season vary by 4-7 weeks and 1 week, respectively. Mean coefficient of variation of seasonal rainfall is 39 %, but monthly variations are higher. These variations make annual crop management and planning difficult each year. Trends show a decrease in the rainfall amounts but improvements in both the temporal distribution of annual rainfall, onset and cessation dates.

  6. Comparison of COD and SS dynamics in a rice catchment during storms between the growing and non-growing season

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Soo; Lee, Jeong-Beom; Lee, Jae-Yong; Li, Si-Hong

    2014-05-01

    We compared the behavior of chemical oxygen demand (COD) and suspended solid (SS) in runoff from a Korean rice field catchment during storm events between growing and non-growing seasons. The study catchment has a size of 21.9 ha with a water source of river. Fertilizers were applied at rates of 91 N kg ha-1 and 18 P kg ha-1 as basal and top dressings. The rice fields are shallowly flooded during most of the growing season, and therefore runoff water always occurs during the growing season. However, runoff water occurs only during storms in the non-growing season. Overall, COD and SS concentrations increased with discharge. Event mean concentration (EMC) of COD in runoff water from the catchment during the non-growing season was 2.6 times higher than that during the growing season. However EMC of SS in runoff water from the paddy field catchment during the non-growing season was almost the same as that during the growing season, much lower than that from the upland catchment. This may be because rice roots and residues in paddy soil during the non-growing season greatly reduce transport of SS associated with soil erosion.

  7. Estimating the Sensitivity of CLM-Crop to Plant Date and Growing Season Length

    NASA Astrophysics Data System (ADS)

    Drewniak, B. A.; Kotamarthi, V. R.

    2012-12-01

    The Community Land Model (CLM), the land component of the Community Earth System Model (CESM), is designed to estimate the land surface response to climate through simulated vegetation phenology and soil carbon and nitrogen dynamics. Since human influences play a significant role shaping the land surface, the vegetation has been expanded to include agriculture (CLM-Crop) for three crop types: corn, soybean, and spring wheat. CLM-Crop parameters, which define crop phenology, are optimized against AmeriFlux observations of gross primary productivity, net ecosystem exchange, and stored biomass and carbon, for two sites in the U.S. growing corn and soybean. However, there is uncertainty in the measurements and using a small subset of data to determine model parameters makes validation difficult. In order to account for the differences in plant behavior across climate zones, an input dataset is used to define the planting dates and the length of the growing season. In order to improve model performance, and to understand the impacts of uncertainty from the input data, we evaluate the sensitivity of crop productivity and production against planting date and the length of the growing season. First, CLM-Crop is modified to establish plant date based on temperature trends for the previous 10-day period, constrained against the range of observed planting dates. This new climate-based model is compared with the standard fixed plant dates to determine how sensitive the model is to when seeding occurs, and how comparable the climate calculated plant dates are to the fixed dates. Next, the length of the growing season will be revised to account for an alternative climate. Finally, both the climate-based planting and new growth season will be simulated together. Results of the different model runs will be compared to the standard model and to observations to determine the importance of planting date and growing season length on crop productivity and yield.

  8. Estimation of Growing Season ET using Wyoming ET Calculator

    NASA Astrophysics Data System (ADS)

    Rasmussen, R. W.; Park, G.

    2011-12-01

    Accurate estimations of Evapotranspiration (ET) and Consumptive Irrigation Requirement (CIR) are essential for water resources planning and management. The Wyoming State Engineer's Office currently determines monthly reference evapotranspiration (ET) with an Excel Spreadsheet ET model using average monthly data from a nearby weather station (usually an airport weather station) for the irrigated area of interest, and interpolates them into daily reference ET using either linear or cubic functions. The purpose of this project is to replace the current Excel model with a GIS-based ET calculator. Our approach uses daily weather data to calculate daily reference and actual ET, and then aggregate actual ET into monthly and seasonal ET. Among many reference ET equations available, the ASCE Standardized Reference Evapotranspiration Equation (ASCE-ET) and the Hargreaves-Samani equations were selected to calculate daily reference ET. Wyoming ET Calculator, a GIS-based ET tool, was developed to calculate daily potential ET, CIR, and actual ET, using daily reference ET, crop coefficients, effective precipitation ratios, and water stress factors. Total monthly and growing season ET and CIR were determined over the Upper Green River Basin in Wyoming. The long term trends of these totals from 1960-2009 were analyzed and compared to trends in weather data (minimum and maximum temperatures, wind speed, and dew point temperature). We also evaluated the total monthly and growing season ET from Wyoming ET Calculator against satellite-based ET (METRIC ET) estimations for June, July, and August of 2009 around an irrigated area near the Wind River Mountain Range in Wyoming. The total monthly ET from Wyoming ET Calculator agrees very well with total monthly ET from METRIC for well-watered crop areas. For other areas, the Wyoming ET Calculator tends to overestimate total monthly ET values than METRIC, because the tool assumes all NLCD crop area are being irrigated.

  9. Responses of Scots pine to waterlogging during growing season

    NASA Astrophysics Data System (ADS)

    Repo, Tapani; Launiainen, Samuli; Lehto, Tarja; Sutinen, Sirkka; Ruhanen, Hanna; Heiskanen, Juha; Laurén, Ari; Silvennoinen, Raimo; Vapaavuori, Elina; Finér, Leena

    2016-04-01

    For the future management and sustainable use of boreal forests it is crucial to consider the rate and strength of tree responses to an elevated water table and the concurrent oxygen limitations, especially in peatlands. We examined the response dynamics of 7-year-old Scots pine (Pinus sylvestris L.) seedlings to a five-week waterlogging (WL) during a growing season in a root lab experiment. WL took place after shoot elongation had ended whereas growth of the trunk diameter was still in progress. We monitored shoots and roots before, during and after WL treatment. Relations between the shoot and root responses, the latter being the primary target of the WL stress, will be discussed. We hypothesize that root responses, in terms of growth by minirhizotron imaging, will appear with delay as compared with the first symptoms in physiology of above-ground organs.

  10. The seasonal timing of warming that controls onset of the growing season.

    PubMed

    Clark, James S; Melillo, Jerry; Mohan, Jacqueline; Salk, Carl

    2014-04-01

    Forecasting how global warming will affect onset of the growing season is essential for predicting terrestrial productivity, but suffers from conflicting evidence. We show that accurate estimates require ways to connect discrete observations of changing tree status (e.g., pre- vs. post budbreak) with continuous responses to fluctuating temperatures. By coherently synthesizing discrete observations with continuous responses to temperature variation, we accurately quantify how increasing temperature variation accelerates onset of growth. Application to warming experiments at two latitudes demonstrates that maximum responses to warming are concentrated in late winter, weeks ahead of the main budbreak period. Given that warming will not occur uniformly over the year, knowledge of when temperature variation has the most impact can guide prediction. Responses are large and heterogeneous, yet predictable. The approach has immediate application to forecasting effects of warming on growing season length, requiring only information that is readily available from weather stations and generated in climate models. PMID:24115181

  11. Growing season methane budget of an Inner Mongolian steppe

    NASA Astrophysics Data System (ADS)

    Liu, Chunyan; Holst, Jirko; Yao, Zhisheng; Brüggemann, Nicolas; Butterbach-Bahl, Klaus; Han, Shenghui; Han, Xingguo; Tas, Bart; Susenbeth, Andreas; Zheng, Xunhua

    We present a methane (CH 4) budget for the area of the Baiyinxile Livestock Farm, which comprises approximately 1/3 of the Xilin river catchment in central Inner Mongolia, P.R. China. The budget calculations comprise the contributions of natural sources and sinks as well as sources related to the main land-use in this region (non-nomadic pastoralism) during the growing season (May-September). We identified as important CH 4 sources floodplains (mean 1.55 ± 0.97 mg CH 4-C m -2 h -1) and domestic ruminants, which are mainly sheep in this area. Within the floodplain significant differences between investigated positions were detected, whereby only positions close-by the river or bayous emitted large amounts of CH 4 (mean up to 6.21 ± 1.83 mg CH 4-C m -2 h -1). Further CH 4 sources were sheepfolds (0.08-0.91 mg CH 4-C m -2 h -1) and pasture faeces (1.34 ± 0.22 mg CH 4-C g -1 faeces dry weight), but they did not play a significant role for the CH 4 budget. In contrast, dung heaps were not a net source of CH 4 (0.0 ± 0.2 for an old and 0.0 ± 0.3 μg CH 4-C kg -1 h -1 for a new dung heap). Trace gas measurements along two landscape transects (volcano, hill slope) revealed expectedly a mean CH 4 uptake (volcano: 76.5 ± 4.3; hill: 28.3 ± 5.3 μg CH 4-C m -2 h -1), which is typical for the aerobic soils in this and other steppe ecosystems. The observed fluxes were rarely influenced by topography. The CH 4 emissions from the floodplain and the sheep were not compensated by the CH 4 oxidation of aerobic steppe soils and thus, this managed semi-arid grassland did not serve as a terrestrial sink, but as a source for this globally important greenhouse gas. The source strength amounted to 1.5-3.6 kg CH 4-C ha -1 during the growing season, corresponding to 3.5-8.7 kg C ha -1 yr -1.

  12. 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.

  13. Seasonal branch and fine root growth of juvenile loblolly pine five growing seasons after fertilization.

    PubMed

    Sword, M. A.; Gravatt, D. A.; Faulkner, P. L.; Chambers, J. L.

    1996-01-01

    In 1989, we established two replications of two fertilization treatments in a 10-year-old loblolly pine (Pinus taeda L.) plantation. Between March and September 1993, branch internode and needle fascicle expansion in the upper and lower third of crowns were measured weekly on three south-facing branches of each of four trees, and new root initiation and elongation were measured at 10-day intervals in three vertical rhizotrons per plot. In one replication, soil water content was measured daily. Fertilization significantly increased the expansion of first flush internodes in the upper crown and first flush needle fascicles in the upper and lower crown. New root growth was stimulated by fertilization in the second half of the growing season. The timing of root growth responses to fertilization corresponded to branch phenologies in the upper and lower crown that were conducive to increased basipetal transport of photosynthate. We conclude, therefore, that new root growth was linked to source-sink activities in the crown. Root initiation was greater in the upper than in the lower part of the soil profile; however, as the growing season progressed and water deficit increased, this relationship was reversed. The effect of soil depth on seasonal root growth was closely associated with water availability, suggesting that root initiation deep in the soil profile is critical for the continued production of new roots in environments subjected to short-term, but relatively severe, water deficits. PMID:14871782

  14. 317/319 phytoremediation site monitoring report - 2003 growing season.

    SciTech Connect

    Negri, M. C.; Gopalakrishnan, G.; Hamilton, C.; Energy Systems

    2004-02-20

    In 1999, Argonne National Laboratory-East (ANL-E) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by hydraulic control of the contaminated plume by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems Division (ES) in the growing season of 2003. ES was tasked with the biomonitoring of the plantation to determine contaminant uptake and groundwater contact. VOCs were found in plant tissue both at the French Drain and the Hydraulic Control locations in varying concentrations, and tritium levels in transpirate was found to continue a trend of higher concentrations compared to the background in the ANL-E area.

  15. Microwave remote sensing of flash droughts during crop growing seasons

    NASA Astrophysics Data System (ADS)

    Yuan, Xing; Ma, Zhuguo; Pan, Ming; Shi, Chunxiang

    2015-04-01

    Severe short-term droughts frequently occurred over China in recent years, with devastating impacts on crop production. Short-term droughts during the crop growing seasons sometimes occur together with abnormally high temperature, and positive feedbacks between the land and atmosphere often intensify the drought conditions. These droughts are recently termed as "flash droughts" due to their rapid development, unusual intensity and devastating impacts. This study assesses the capability of microwave remote sensing in detecting soil moisture droughts over China and in providing early warnings. The 22-year (1992-2013) satellite surface soil moisture retrievals produced by the European Space Agency Climate Change Initiative (ESA CCI) are compared against the in-situ observations at 312 stations in China, the ERA Interim and GLDAS soil moisture reanalysis, and the observed rainfall deficit. Both the reanalysis and remote sensing products can only detect less than 60% of drought months over most in-situ stations, but they capture the responses of inter-annual drought variations to ENSO at river basin scales quite well. As compared with reanalysis, the satellite products provide independent drought information over sparsely observed regions such as northwestern China, and the active microwave product with better vegetation penetration works the best in southern China. This study suggests that the microwave remote sensing data is useful for soil moisture drought monitor as well as verification for drought modeling or forecasting.

  16. 317/319 phytoremediation site monitoring report - 2005 growing season.

    SciTech Connect

    Negri, M. C.; Gopalakrishnan, G.; Energy Systems

    2006-03-31

    In 1999, Argonne National Laboratory (ANL) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by hydraulic control of the contaminated plume by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems Division (ES) in the growing season of 2005. Monitoring of the planted trees began soon after the trees were installed in 1999 and has been conducted every summer since then. As the trees grew and consolidated their growth into the contaminated soil and groundwater, their exposure to the contaminants was progressively shown through tissue sampling. However, as trees grow larger, some of the findings obtained in the early years when trees were much smaller may not hold true now and need to be verified again. During the 2005 sampling campaign, data from the French Drain area confirmed the results obtained in 2004 and earlier, and the previously found correlation between soil and branch concentrations. During the 2005 summer, studies under controlled conditions (cartridges) have shown a generally linear dose response of PCE uptake, and have also shown that tree concentrations of PCE decrease after flushing with clean water in short times when trees are exposed to low levels of the contaminant. This data proves that tree concentrations are transient, and that with proper time levels can return close to background

  17. Germany wide seasonal flood risk analysis for agricultural crops

    NASA Astrophysics Data System (ADS)

    Klaus, Stefan; Kreibich, Heidi; Kuhlmann, Bernd; Merz, Bruno; Schröter, Kai

    2016-04-01

    In recent years, large-scale flood risk analysis and mapping has gained attention. Regional to national risk assessments are needed, for example, for national risk policy developments, for large-scale disaster management planning and in the (re-)insurance industry. Despite increasing requests for comprehensive risk assessments some sectors have not received much scientific attention, one of these is the agricultural sector. In contrast to other sectors, agricultural crop losses depend strongly on the season. Also flood probability shows seasonal variation. Thus, the temporal superposition of high flood susceptibility of crops and high flood probability plays an important role for agricultural flood risk. To investigate this interrelation and provide a large-scale overview of agricultural flood risk in Germany, an agricultural crop loss model is used for crop susceptibility analyses and Germany wide seasonal flood-frequency analyses are undertaken to derive seasonal flood patterns. As a result, a Germany wide map of agricultural flood risk is shown as well as the crop type most at risk in a specific region. The risk maps may provide guidance for federal state-wide coordinated designation of retention areas.

  18. A seasonal agricultural drought forecast system for food-insecure regions of East Africa

    USGS Publications Warehouse

    Shukla, Shraddhanand; McNally, Amy; Husak, Gregory; Funk, Christopher C.

    2014-01-01

     The increasing food and water demands of East Africa's growing population are stressing the region's inconsistent water resources and rain-fed agriculture. More accurate seasonal agricultural drought forecasts for this region can inform better water and agricultural management decisions, support optimal allocation of the region's water resources, and mitigate socio-economic losses incurred by droughts and floods. Here we describe the development and implementation of a seasonal agricultural drought forecast system for East Africa (EA) that provides decision support for the Famine Early Warning Systems Network's science team. We evaluate this forecast system for a region of equatorial EA (2° S to 8° N, and 36° to 46° E) for the March-April-May growing season. This domain encompasses one of the most food insecure, climatically variable and socio-economically vulnerable regions in EA, and potentially the world: this region has experienced famine as recently as 2011. To assess the agricultural outlook for the upcoming season our forecast system simulates soil moisture (SM) scenarios using the Variable Infiltration Capacity (VIC) hydrologic model forced with climate scenarios for the upcoming season. First, to show that the VIC model is appropriate for this application we forced the model with high quality atmospheric observations and found that the resulting SM values were consistent with the Food and Agriculture Organization's (FAO's) Water Requirement Satisfaction Index (WRSI), an index used by FEWS NET to estimate crop yields. Next we tested our forecasting system with hindcast runs (1993–2012). We found that initializing SM forecasts with start-of-season (5 March) SM conditions resulted in useful SM forecast skill (> 0.5 correlation) at 1-month, and in some cases at 3 month lead times. Similarly, when the forecast was initialized with mid-season (i.e. 5 April) SM conditions the skill until the end-of-season improved. This shows that early-season rainfall

  19. A seasonal agricultural drought forecast system for food-insecure regions of East Africa

    NASA Astrophysics Data System (ADS)

    Shukla, S.; McNally, A.; Husak, G.; Funk, C.

    2014-03-01

    The increasing food and water demands of East Africa's growing population are stressing the region's inconsistent water resources and rain-fed agriculture. More accurate seasonal agricultural drought forecasts for this region can inform better water and agricultural management decisions, support optimal allocation of the region's water resources, and mitigate socio-economic losses incurred by droughts and floods. Here we describe the development and implementation of a seasonal agricultural drought forecast system for East Africa (EA) that provides decision support for the Famine Early Warning Systems Network's science team. We evaluate this forecast system for a region of equatorial EA (2° S to 8° N, and 36° to 46° E) for the March-April-May growing season. This domain encompasses one of the most food insecure, climatically variable and socio-economically vulnerable regions in EA, and potentially the world: this region has experienced famine as recently as 2011. To assess the agricultural outlook for the upcoming season our forecast system simulates soil moisture (SM) scenarios using the Variable Infiltration Capacity (VIC) hydrologic model forced with climate scenarios for the upcoming season. First, to show that the VIC model is appropriate for this application we forced the model with high quality atmospheric observations and found that the resulting SM values were consistent with the Food and Agriculture Organization's (FAO's) Water Requirement Satisfaction Index (WRSI), an index used by FEWS NET to estimate crop yields. Next we tested our forecasting system with hindcast runs (1993-2012). We found that initializing SM forecasts with start-of-season (5 March) SM conditions resulted in useful SM forecast skill (> 0.5 correlation) at 1-month, and in some cases at 3 month lead times. Similarly, when the forecast was initialized with mid-season (i.e. 5 April) SM conditions the skill until the end-of-season improved. This shows that early-season rainfall is

  20. Coordination of Different Phenological Events during the Growing Season

    NASA Astrophysics Data System (ADS)

    Berninger, F.; Lemieux, J.; Zhai, L.

    2008-12-01

    In two separate studies we followed the phenological development of black spruce on different microsites and of three congeneric species (Jack pine, white birch and trembling aspen) with different growth patterns on a single site. All studies were done in the northern black spruce belt in northern Quebec (northern boreal forest). We followed several phenological points during the growing season (bud development, shoot extension, onset of the diameter growth, diameter growth, budset, end of diamter growth, maximum foliage growth, end of foliage growth, end of latewood differentiation). We hypothesized that phenological development and growth are internally regulated in trees in a way that: (1) the time that it takes to pass through a certain phenological phase is similar for all trees. (2) trees that start bud development earlier will start also diameter growth earlier (3) that growth of "early trees" will end earlier.These kind of relationships are suggested by the hormonal theory of tree growth and would be useful to understand when trees are vulnerable to different abiotic and biotic events. The different sites had a clear impact on phenology which was linked to the microclimate of the site. Bud- development of the warm site was clearly more rapid on a warmer site, separated from about 100 meters from weter colder sites. However, coordination between sites broke down and clear differences in the early stages of bud development were already less clear at the late stages of bud development. The end of growth was quite similar between the sites. Between species it became evident that different species have similar "phenological timetales" and the onset. Ranks of the species were different for budbreak and the onset of xylem development. Also, birch, the species with an earlier budbreak reached full leaf size later than aspen. In addition the often proclaimed linkage between end of extension growth and onset of latewood formation did not hold for Jack pine. The

  1. Changing water availability during the African maize-growing season, 1979-2010

    NASA Astrophysics Data System (ADS)

    Estes, Lyndon D.; Chaney, Nathaniel W.; Herrera-Estrada, Julio; Sheffield, Justin; Caylor, Kelly K.; Wood, Eric F.

    2014-07-01

    Understanding how global change is impacting African agriculture requires a full physical accounting of water supply and demand, but accurate, gridded data on key drivers (e.g., humidity) are generally unavailable. We used a new bias-corrected meteorological dataset to analyze changes in precipitation (supply), potential evapotranspiration ({{E}_{p}}, demand), and water availability (expressed as the ratio P/{{E}_{p}}) in 20 countries (focusing on their maize-growing regions and seasons), between 1979 and 2010, and the factors driving changes in {{E}_{p}}. Maize-growing areas in Southern Africa, particularly South Africa, benefitted from increased water availability due in large part to demand declines driven primarily by declining net radiation, increasing vapor pressure, and falling temperatures (with no effect from changing windspeed), with smaller increases in supply. Sahelian zone countries in West Africa, as well as Ethiopia in East Africa, had strong increases in availability driven primarily by rainfall rebounding from the long-term Sahelian droughts, with little change or small reductions in demand. However, intra-seasonal supply variability generally increased in West and East Africa. Across all three regions, declining net radiation contributed downwards pressure on demand, generally over-riding upwards pressure caused by increasing temperatures, the regional effects of which were largest in East Africa. A small number of countries, mostly in or near East Africa (Tanzania and Malawi) experienced declines in water availability primarily due to decreased rainfall, but exacerbated by increasing demand. Much of the reduced water availability in East Africa occurred during the more sensitive middle part of the maize-growing season, suggesting negative consequences for maize production.

  2. Impacts of climate change on the growing season in the United States

    USGS Publications Warehouse

    Markstrom, Steven L.; Hay, Lauren E.

    2011-01-01

    Understanding the effects of climate change on the vegetative growing season is key to quantifying future hydrologic water budget conditions. The U.S. Geological Survey modeled changes in future growing season length at 14 basins across 11 states. Simulations for each basin were generated using five general circulation models with three emission scenarios as inputs to the Precipitation-Runoff Modeling System (PRMS). PRMS is a deterministic, distributed-parameter, watershed model developed to simulate the effects of various combinations of precipitation, climate, and land use on watershed response. PRMS was modified to include a growing season calculation in this study. The growing season was examined for trends in the total length (annual), as well as changes in the timing of onset (spring) and the end (fall) of the growing season. The results showed an increase in the annual growing season length in all 14 basins, averaging 27–47 days for the three emission scenarios. The change in the spring and fall growing season onset and end varied across the 14 basins, with larger increases in the total length of the growing season occurring in the mountainous regions and smaller increases occurring in the Midwest, Northeast, and Southeast regions. The Clear Creek basin, 1 of the 14 basins in this study, was evaluated to examine the growing season length determined by emission scenario, as compared to a growing season length fixed baseline condition. The Clear Creek basin showed substantial variation in hydrologic responses, including streamflow, as a result of growing season length determined by emission scenario.

  3. Growing Season Carbon Dioxide Exchange in Flooded Non-Mulching and Non-Flooded Mulching Cotton

    PubMed Central

    Li, Zhi-guo; Zhang, Run-hua; Wang, Xiu-jun; Chen, Fang; Tian, Chang-yan

    2012-01-01

    There is much interest in the role that agricultural practices might play in sequestering carbon to help offset rising atmospheric CO2 concentrations. However, limited information exists regarding the potential for increased carbon sequestration of different management strategies. The objective of this study was to quantify and contrast carbon dioxide exchange in traditional non-mulching with flooding irrigation (TF) and plastic film mulching with drip irrigation (PM) cotton (Gossypium hirsutum L.) fields in northwest China. Net primary productivity (NPP), soil heterotrophic respiration (Rh) and net ecosystem productivity (NEP) were measured during the growing seasons in 2009 and 2010. As compared with TF, PM significantly increased the aboveground and belowground biomass and the NPP (340 g C m−2 season−1) of cotton, and decreased the Rh (89 g C m−2 season−1) (p<0.05). In a growing season, PM had a higher carbon sequestration in terms of NEP of ∼ 429 g C m−2 season−1 than the TF. These results demonstrate that conversion of this type of land use to mulching practices is an effective way to increase carbon sequestration in the short term in cotton systems of arid areas. PMID:23226376

  4. Changes of accumulated temperature, growing season and precipitation in the North China Plain from 1961 to 2009

    NASA Astrophysics Data System (ADS)

    Song, Yanling; Zhao, Yanxia; Wang, Chunyi

    2011-08-01

    Using the high-quality observed meteorological data, changes of the thermal conditions and precipitation over the North China Plain from 1961 to 2009 were examined. Trends of accumulated temperature and negative temperature, growing season duration, as well as seasonal and annual rainfalls at 48 stations were analyzed. The results show that the accumulated temperature increased significantly by 348.5°C day due to global warming during 1961-2009 while the absolute accumulated negative temperature decreased apparently by 175.3°C day. The start of growing season displayed a significant negative trend of -14.3 days during 1961-2009, but the end of growing season delayed insignificantly by 6.7 days. As a result, the length of growing season increased by 21.0 days. The annual and autumn rainfalls decreased slightly while summer rainfall and summer rainy days decreased significantly. In contrast, spring rainfall increased slightly without significant trends. All the results indicate that the thermal conditions were improved to benefit the crop growth over the North China Plain during 1961-2009, and the decreasing annual and summer rainfalls had no direct negative impact on the crop growth. But the decreasing summer rainfall was likely to influence the water resources in North China, especially the underground water, reservoir water, as well as river runoff, which would have influenced the irrigation of agriculture.

  5. Spatiotemporal properties of growing season indices during 1961-2010 and possible association with agroclimatological regionalization of dominant crops in Xinjiang, China

    NASA Astrophysics Data System (ADS)

    Ci, Hui; Zhang, Qiang; Singh, Vijay P.; Xiao, Mingzhong; Liu, Lin

    2016-08-01

    Variations of frost days and growing season length (GSL) have been drawing increasing attention due to their impact on agriculture. The Xinjiang region in China is climatically an arid region and plays an important role in agriculture development. In this study, the GSL and frost events are analyzed in both space and time, based on the daily minimum, mean and maximum air surface temperature data covering a period of 1961-2010. Results indicate that: (1) a significant lengthening of GSL is detected during 1961-2010 in Xinjiang, China. The increasing rate of GSL over Xinjiang is about 2.5 days per decade. Besides, the starting time of growing season is 0.7 days earlier per decade and the ending time is 1.6 days later per decade. Generally, GSL in southern Xinjiang has larger increasing magnitude when compared to other regions of Xinjiang; (2) longer GSL and larger changing magnitude of growing season start (GSS), growing season end (GSE) and GSL in southern Xinjiang implies higher sensitivity of the growing season response to climate warming. Besides, GSL is in close relation with latitude, and higher latitude usually corresponds to later start and earlier end of growing season, and hence shorter GSL. In general, a northward increase of 1° latitude triggers an 8-day delay of the starting time of growing season, 6-day advance of the ending time of growing season, and thus the GSL is 14 days shorter; (3) GSL under different rates can reflect light and heat resources over Xinjiang. The GSL related to 80 % guarantee rate is 5-14 days shorter than the long-term annual mean GSL; (4) Lengthening of GSL has the potential to increase agricultural production. However, negative influences by climate warming, such as enhanced evapotranspiration, increasing weeds, insects, and pathogen-mediated plant diseases, should also be considered in planning, management and development of agriculture in Xinjiang.

  6. Spatiotemporal properties of growing season indices during 1961-2010 and possible association with agroclimatological regionalization of dominant crops in Xinjiang, China

    NASA Astrophysics Data System (ADS)

    Ci, Hui; Zhang, Qiang; Singh, Vijay P.; Xiao, Mingzhong; Liu, Lin

    2015-11-01

    Variations of frost days and growing season length (GSL) have been drawing increasing attention due to their impact on agriculture. The Xinjiang region in China is climatically an arid region and plays an important role in agriculture development. In this study, the GSL and frost events are analyzed in both space and time, based on the daily minimum, mean and maximum air surface temperature data covering a period of 1961-2010. Results indicate that: (1) a significant lengthening of GSL is detected during 1961-2010 in Xinjiang, China. The increasing rate of GSL over Xinjiang is about 2.5 days per decade. Besides, the starting time of growing season is 0.7 days earlier per decade and the ending time is 1.6 days later per decade. Generally, GSL in southern Xinjiang has larger increasing magnitude when compared to other regions of Xinjiang; (2) longer GSL and larger changing magnitude of growing season start (GSS), growing season end (GSE) and GSL in southern Xinjiang implies higher sensitivity of the growing season response to climate warming. Besides, GSL is in close relation with latitude, and higher latitude usually corresponds to later start and earlier end of growing season, and hence shorter GSL. In general, a northward increase of 1° latitude triggers an 8-day delay of the starting time of growing season, 6-day advance of the ending time of growing season, and thus the GSL is 14 days shorter; (3) GSL under different rates can reflect light and heat resources over Xinjiang. The GSL related to 80 % guarantee rate is 5-14 days shorter than the long-term annual mean GSL; (4) Lengthening of GSL has the potential to increase agricultural production. However, negative influences by climate warming, such as enhanced evapotranspiration, increasing weeds, insects, and pathogen-mediated plant diseases, should also be considered in planning, management and development of agriculture in Xinjiang.

  7. 317/319 phytoremediation site monitoring report - 2004 growing season.

    SciTech Connect

    Negri, M. C.; Gopalakrishnan, G.; Bogner, J.; Energy Systems

    2009-02-21

    In 1999, Argonne National Laboratory (ANL) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by hydraulic control of the contaminated plume by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems Division (ES) in the growing season of 2004. Monitoring of the planted trees began soon after the trees were installed in 1999 and has been conducted every summer since then. As the trees grew and consolidated their growth into the contaminated soil and groundwater, their exposure to the contaminants was progressively shown through tissue sampling. Since the inception of the project, significant progress was made in the refinement and testing of the analytical method (for which no official method is available), the determination of the optimal tissue for sampling, and of the variability of the concentrations within a specific tree. An understanding has also been developed on background concentrations of VOCs, and how to discriminate between VOCs that are associated with plant tissue because of aerial or of soil/groundwater uptake pathways. Also, during the 2003 sampling campaign, core samples from tree trunks were collected for the first time (the trees were large enough to stand the procedure). Data collected from the French Drain area last year supported the hypothesis that a correlation was present between

  8. Likely changes in growing season indices under a climate change scenario for crop production in South Africa

    NASA Astrophysics Data System (ADS)

    Ambrosino, C.; Chandler, R. E.; Todd, M. C.

    2011-12-01

    Agriculture is still the major source of income and livelihood for most of South Africa's population, and cereals and grains are among the country's most important crops. In particular, the largest locally produced field crop and the most important source of carbohydrates in South Africa is maize (Zea mays L.). As well as extensive monoculture, maize production also dominates the smallholder farming system in areas such as the Limpopo District in north-east South Africa. It is therefore critical to understand the year-to-year changes in the planting season and rainfall characteristics in order to introduce management decision and mitigation measures in the agricultural sector (e.g. planting of drought-resistant crops or the choice between long and short-season cultivars). Indeed, one of the strategies that may be easily introduced by farmers is shifting the crop planting dates to adjust to changes in the rainfall regimes. The study presented here aims to characterise the inter-annual growing season variability through the use of 7 indices derived from daily precipitation, considered the most critical factor in rain-fed agriculture, having an impact on maize production. A statistical model is developed to generate daily rainfall sequences for the study area driven by large scale climate controls. An independent validation period is chosen to evaluate the performance of the statistical model in the rainfall generation process. Onset, length and cessation of the growing season, as well as indices representing the length of the mean and maximum dry spell during the season are derived from the area average daily simulated precipitation values. The fraction of rainy days and total precipitation during the growing season are also calculated. Finally, the projected change of the growing season indices between two investigated periods in the 20th and 21st centuries is investigated under a climate change scenario (a1b; e.g.: Fig.1). The outputs of this study may be used to

  9. Separating agricultural and non-agricultural fire seasonality at regional scales

    NASA Astrophysics Data System (ADS)

    Magi, B. I.; Rabin, S.; Shevliakova, E.; Pacala, S.

    2012-08-01

    The timing and length of burning seasons in different parts of the world depend on climate, land-cover characteristics, and human activities. In this study, global burned area estimates are used in conjunction with global gridded distributions of agricultural land-cover types (defined as the sum of cropland and pasture area) to separate the seasonality of agricultural burning practices from that of non-agricultural fire. The results presented in this study show that agricultural and non-agricultural land experience broadly different fire seasonality patterns that are not always linked to climate conditions. We highlight these differences on a regional basis, examining variations in both agricultural land cover and associated cultural practices to help explain our results. While we discuss two land-cover categories, the methods can be generalized to derive seasonality for any number of land uses or cover types. This will be useful as global fire models evolve to be fully interactive with land-use and land-cover change in the next generation of Earth system models.

  10. Separating agricultural and non-agricultural fire seasonality at regional scales

    NASA Astrophysics Data System (ADS)

    Magi, B. I.; Rabin, S.; Shevliakova, E.; Pacala, S.

    2012-05-01

    The timing and length of burning seasons in different parts of the world depend on climate, land cover characteristics, and human activities. In this study, global fire data from satellite-based instruments are used in conjunction with global gridded distributions of agricultural land cover types (defined as the sum of cropland and pasture area) to separate the seasonality of agricultural burning practices from that of non-agricultural fire. The results presented in this study show that agricultural and non-agricultural land experience broadly different fire seasonality patterns that are not always linked to climate conditions. We highlight these differences on a regional basis, examining variations in both agricultural land cover and associated cultural practices to help explain our results. While we discuss two land cover categories, the methods can be generalized to derive seasonality for any number of land uses or cover types. This will be useful as global fire models evolve to be fully interactive with land use and land cover change in the next generation of Earth system models.

  11. Reflectance and internal structure of leaves from several crops during a growing season.

    NASA Technical Reports Server (NTRS)

    Sinclair, T. R.; Hoffer, R. M.; Schreiber, M. M.

    1971-01-01

    Measurements of spectral reflectance characteristics during a growing season of leaves from six crops are reported. These crops include soybeans, wheat, oats, sorghum, corn, and sudangrass. The characteristics measured are related to changes in leaf structure and water content.

  12. Reserves accumulated in non-photosynthetic organs during the previous growing season drive plant defenses and growth in aspen in the subsequent growing season.

    PubMed

    Najar, Ahmed; Landhäusser, Simon M; Whitehill, Justin G A; Bonello, Pierluigi; Erbilgin, Nadir

    2014-01-01

    Plants store non-structural carbohydrates (NSC), nitrogen (N), as well as other macro and micronutrients, in their stems and roots; the role of these stored reserves in plant growth and defense under herbivory pressure is poorly understood, particularly in trees. Trembling aspen (Populus tremuloides) seedlings with different NSC and N reserves accumulated during the previous growing season were generated in the greenhouse. Based on NSC and N contents, seedlings were assigned to one of three reserve statuses: Low N-Low NSC, High N-Medium NSC, or High N-High NSC. In the subsequent growing season, half of the seedlings in each reserve status was subjected to defoliation by forest tent caterpillar (Malacosoma disstria) while the other half was left untreated. Following defoliation, the effect of reserves was measured on foliar chemistry (N, NSC) and caterpillar performance (larval development). Due to their importance in herbivore feeding, we also quantified concentrations of phenolic glycoside compounds in foliage. Seedlings in Low N-Low NSC reserve status contained higher amounts of induced phenolic glycosides, grew little, and supported fewer caterpillars. In contrast, aspen seedlings in High N-Medium or High NSC reserve statuses contained lower amounts of induced phenolic glycosides, grew faster, and some of the caterpillars which fed on these seedlings developed up to their fourth instar. Furthermore, multiple regression analysis indicated that foliar phenolic glycoside concentration was related to reserve chemistry (NSC, N). Overall, these results demonstrate that reserves accumulated during the previous growing season can influence tree defense and growth in the subsequent growing season. Additionally, our study concluded that the NSC/N ratio of reserves in the previous growing season represents a better measure of resources available for use in defense and growth than the foliar NSC/N ratios. PMID:24363094

  13. Calculating High Resolution CWSI Maps for Entire Growing Season of a Cultivated Barley Field with UAV-Collected Surface Temperatures.

    NASA Astrophysics Data System (ADS)

    Hoffmann, H.; Jensen, R.; Nieto Solana, H.; Friborg, T.; Thomsen, A.

    2015-12-01

    With agriculture as the largest consumer of freshwater and an overall increasing pressure on water resources, developing more efficient irrigation systems is important. Combining the crop water stress index (CWSI) with unmanned aerial vehicles (UAVs) enables detection of which specific areas within a cultivated field that requires irrigation to ensure healthy growing plants. In this study remotely sensed, high resolution surface temperatures are collected with a thermal camera onboard an UAV. Temperatures are used to calculate spatially distributed, high resolution CWSI maps over a barley field during growing seasons 2014 and 2015. In early stages of the barley growing season, surface temperatures are an ensemble of both soil and canopy temperatures. Canopy temperatures are extracted using leaf area index and the two source energy balance modelling scheme. This approach enables CWSI calculations for homogeneous and evenly distributed crops (such as barley) during early as well as late stages of a growing season. CWSI maps are calculated using both an empirical and an analytical approach and are compared and validated against modelled canopy conductance and transpiration rates.

  14. Warming and elevated CO2 lead to longer growing season in temperate grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Observational data over time suggest that as climate has warmed the growing season has lengthened, although experimental warming shortens early-growing species’ life cycles. Are other plant species living longer? We found that experimental warming in a temperate, semi-arid grassland led to earlier l...

  15. Increased photosynthesis compensates for shorter growing season in subarctic tundra - seven years of snow accumulation manipulations

    NASA Astrophysics Data System (ADS)

    Bosiö, Julia; Johansson, Margareta; Njuabe, Herbert; Christensen, Torben R.

    2013-04-01

    This study was initiated to analyze the effect of snow cover on photosynthesis and plant growth in subarctic mires underlain by permafrost. Due to their narrow environmental window these raised bogs, often referred to as palsa mires, are highly sensitive to climatic changes. In Fennoscandia palsa mires are currently subjected to climate related thawing and shift in vegetational and hydrological patterns. Yet, we know little of how these subarctic permafrost mires react and feed back to such changes. By using snow fences to hinder snow drift the accumulation of snow was increased in six plots (10x20 m) in a snow manipulation experiment on a subarctic permafrost mire in northern Sweden. The thicker snow pack prolongs the duration of the snow cover in spring, causing a delay in the onset, as well as an overall shortening of the growing season. By measuring incoming and reflected photosynthetic active radiation (PAR) we wanted to address the question whether the increased snow thickness and associated delay of the growing season start affected the absorbed PAR and the accumulated gross primary production (GPP) over the season. The reflected PAR was measured at twelve plots where six of the plots experienced increased snow accumulation (treatment), and remaining six plots were untreated (control). Minikin QT sensors with integrated data loggers logged incoming and reflected PAR hourly throughout the growing seasons of 2011 and 2012. In July - September 2010 PAR measurements were coupled with flux chamber measurements to assess GPP and light use efficiency of the plots. The increased accumulation of snow prolonged the duration of the snow cover in spring, causing a delay in the onset, as well as an overall shortening of the growing season in the treated plots. The end of the growing season was not affected by the snow manipulation. The delay of the growing season start and hence overall shortening of the growing season in the treatment plots was 18 days in 2011 and 3

  16. Pan-Arctic linkages between snow accumulation and growing season air temperature, soil moisture and vegetation

    NASA Astrophysics Data System (ADS)

    Luus, K. A.; Gel, Y.; Lin, J. C.; Kelly, R. E. J.; Duguay, C. R.

    2013-01-01

    Arctic field studies have indicated that the air temperature, soil moisture and vegetation at a site influence the quantity of snow accumulated, and that snow accumulation can alter growing season soil moisture and vegetation. Climate change is predicted to bring about warmer air temperatures, greater snow accumulation and northward movements of the shrub and tree lines. Understanding the response of northern environments to changes in snow and growing season land surface characteristics requires: (1) insights into the present-day linkages between snow and growing season land surface characteristics; and (2) the ability to continue to monitor these associations over time across the vast pan-Arctic. The objective of this study was therefore to examine the pan-Arctic (north of 60° N) linkages between two temporally distinct data products created from AMSR-E satellite passive microwave observations: GlobSnow snow water equivalent, and NTSG (growing season air temperature, soil moisture and vegetation transmissivity). Due to the complex and interconnected nature of processes determining snow and growing season land surface characteristics, these associations were analyzed using the modern non-parametric technique of Alternating Conditional Expectations (ACE), as this approach does not impose a predefined analytic form. Findings indicate that regions with lower vegetation transmissivity (more biomass) at the start and end of the growing season tend to accumulate less snow at the start and end of the snow season, possibly due to interception and shading. Warmer air temperatures at the start and end of the growing season were associated with diminished snow accumulation at the start and end of the snow season. High latitude sites with warmer mean annual growing season temperatures tended to accumulate more snow, probably due to the greater availability of water vapor for snow season precipitation at warmer locations. Regions with drier soils preceding snow onset tended

  17. Impact of mulches and growing season on indicator bacteria survival during lettuce cultivation.

    PubMed

    Xu, Aixia; Buchanan, Robert L; Micallef, Shirley A

    2016-05-01

    In fresh produce production, the use of mulches as ground cover to retain moisture and control weeds is a common agricultural practice, but the influence that various mulches have on enteric pathogen survival and dispersal is unknown. The goal of this study was to assess the impact of different mulching methods on the survival of soil and epiphytic fecal indicator bacteria on organically grown lettuce during different growing seasons. Organically managed lettuce, cultivated with various ground covers--polyethylene plastic, corn-based biodegradable plastic, paper and straw mulch--and bare ground as a no-mulch control, was overhead inoculated with manure-contaminated water containing known levels of generic Escherichia coli and Enterococcus spp. Leaves and soil samples were collected at intervals over a two week period on days 0, 1, 3, 5, 7, 10 and 14, and quantitatively assessed for E. coli, fecal coliforms and Enterococcus spp. Data were analyzed using mixed models with repeated measures and an exponential decline with asymptote survival model. Indicator bacterial concentrations in the lettuce phyllosphere decreased over time under all treatments, with more rapid E. coli declines in the fall than in the spring (p<0.01). Persistence of E. coli in spring was correlated with higher maximum and minimum temperatures in this season, and more regular rainfall. The survival model gave very good fits for the progression of E. coli concentrations in the phyllosphere over time (R(2)=0.88 ± 0.12). In the spring season, decline rates of E. coli counts were faster (2013 p=0.18; 2014 p<0.005) for the bare ground-cultivated lettuce compared to mulches. In fall 2014, the E. coli decline rate on paper mulch-grown lettuce was higher (p<0.005). Bacteria fluctuated more, and persisted longer, in soil compared to lettuce phyllosphere, and mulch type was a factor for fecal coliform levels (p<0.05), with higher counts retrieved under plastic mulches in all trials, and higher enterococci

  18. A seasonal agricultural drought forecast system for food-insecure regions of East Africa

    NASA Astrophysics Data System (ADS)

    Shukla, S.; McNally, A.; Husak, G.; Funk, C.

    2014-10-01

    The increasing food and water demands of East Africa's growing population are stressing the region's inconsistent water resources and rain-fed agriculture. More accurate seasonal agricultural drought forecasts for this region can inform better water and agropastoral management decisions, support optimal allocation of the region's water resources, and mitigate socioeconomic losses incurred by droughts and floods. Here we describe the development and implementation of a seasonal agricultural drought forecast system for East Africa (EA) that provides decision support for the Famine Early Warning Systems Network's (FEWS NET) science team. We evaluate this forecast system for a region of equatorial EA (2° S-8° N, 36-46° E) for the March-April-May (MAM) growing season. This domain encompasses one of the most food-insecure, climatically variable, and socioeconomically vulnerable regions in EA, and potentially the world; this region has experienced famine as recently as 2011. To produce an "agricultural outlook", our forecast system simulates soil moisture (SM) scenarios using the Variable Infiltration Capacity (VIC) hydrologic model forced with climate scenarios describing the upcoming season. First, we forced the VIC model with high-quality atmospheric observations to produce baseline soil moisture (SM) estimates (here after referred as SM a posteriori estimates). These compared favorably (correlation = 0.75) with the water requirement satisfaction index (WRSI), an index that the FEWS NET uses to estimate crop yields. Next, we evaluated the SM forecasts generated by this system on 5 March and 5 April of each year between 1993 and 2012 by comparing them with the corresponding SM a posteriori estimates. We found that initializing SM forecasts with start-of-season (SOS) (5 March) SM conditions resulted in useful SM forecast skill (> 0.5 correlation) at 1-month and, in some cases, 3-month lead times. Similarly, when the forecast was initialized with midseason (i.e., 5

  19. Impact of soil moisture changes on growing season length at a teak plantation in Northern Thailand

    NASA Astrophysics Data System (ADS)

    Yoshifuji, N.; Kumagai, T.; Tantasirin, C.; Suzuki, M.

    2008-12-01

    Growing season length is an important factor affecting energy, water, and carbon exchange at deciduous forests. However, our understandings about the extent of inter-annual variation in growing season length and its cause of deciduous forests in tropical region are still not enough, though the impact of modification of growing season length is likely to be critical especially in tropical region because of high radiant energy throughout the year. In order to clarify the extent of inter-annual variation in growing season length and its major cause of a teak plantation in Northern Thailand, we monitored radiative transmittance through the canopy and heat-pulse velocities of canopy trees for 7-year period. We found large inter-annual variations in the timings of leaf-out, leaf-fall, and the start and stop of transpiration. As a result, we revealed that the year-to-year variation in the length of canopy duration and transpiration period spanned about 60 days. It was also found that these large year-to-year variations can be explained by the differences in the timings of soil moisture changes caused by the differences in the timings of rainfall occurrence. These results imply a profound potential impact of modification of rainfall regime on canopy-atmosphere water and carbon exchange on annual time scale through the modification of growing season length.

  20. Agricultural Green Revolution as a driver of increasing atmospheric CO2 seasonal amplitude.

    PubMed

    Zeng, Ning; Zhao, Fang; Collatz, George J; Kalnay, Eugenia; Salawitch, Ross J; West, Tristram O; Guanter, Luis

    2014-11-20

    The atmospheric carbon dioxide (CO2) record displays a prominent seasonal cycle that arises mainly from changes in vegetation growth and the corresponding CO2 uptake during the boreal spring and summer growing seasons and CO2 release during the autumn and winter seasons. The CO2 seasonal amplitude has increased over the past five decades, suggesting an increase in Northern Hemisphere biospheric activity. It has been proposed that vegetation growth may have been stimulated by higher concentrations of CO2 as well as by warming in recent decades, but such mechanisms have been unable to explain the full range and magnitude of the observed increase in CO2 seasonal amplitude. Here we suggest that the intensification of agriculture (the Green Revolution, in which much greater crop yield per unit area was achieved by hybridization, irrigation and fertilization) during the past five decades is a driver of changes in the seasonal characteristics of the global carbon cycle. Our analysis of CO2 data and atmospheric inversions shows a robust 15 per cent long-term increase in CO2 seasonal amplitude from 1961 to 2010, punctuated by large decadal and interannual variations. Using a terrestrial carbon cycle model that takes into account high-yield cultivars, fertilizer use and irrigation, we find that the long-term increase in CO2 seasonal amplitude arises from two major regions: the mid-latitude cropland between 25° N and 60° N and the high-latitude natural vegetation between 50° N and 70° N. The long-term trend of seasonal amplitude increase is 0.311 ± 0.027 per cent per year, of which sensitivity experiments attribute 45, 29 and 26 per cent to land-use change, climate variability and change, and increased productivity due to CO2 fertilization, respectively. Vegetation growth was earlier by one to two weeks, as measured by the mid-point of vegetation carbon uptake, and took up 0.5 petagrams more carbon in July, the height of the growing season, during 2001-2010 than in

  1. Agricultural Green Revolution as a driver of increasing atmospheric CO2 seasonal amplitude

    NASA Astrophysics Data System (ADS)

    Zeng, Ning; Zhao, Fang; Collatz, George J.; Kalnay, Eugenia; Salawitch, Ross J.; West, Tristram O.; Guanter, Luis

    2014-11-01

    The atmospheric carbon dioxide (CO2) record displays a prominent seasonal cycle that arises mainly from changes in vegetation growth and the corresponding CO2 uptake during the boreal spring and summer growing seasons and CO2 release during the autumn and winter seasons. The CO2 seasonal amplitude has increased over the past five decades, suggesting an increase in Northern Hemisphere biospheric activity. It has been proposed that vegetation growth may have been stimulated by higher concentrations of CO2 as well as by warming in recent decades, but such mechanisms have been unable to explain the full range and magnitude of the observed increase in CO2 seasonal amplitude. Here we suggest that the intensification of agriculture (the Green Revolution, in which much greater crop yield per unit area was achieved by hybridization, irrigation and fertilization) during the past five decades is a driver of changes in the seasonal characteristics of the global carbon cycle. Our analysis of CO2 data and atmospheric inversions shows a robust 15 per cent long-term increase in CO2 seasonal amplitude from 1961 to 2010, punctuated by large decadal and interannual variations. Using a terrestrial carbon cycle model that takes into account high-yield cultivars, fertilizer use and irrigation, we find that the long-term increase in CO2 seasonal amplitude arises from two major regions: the mid-latitude cropland between 25° N and 60° N and the high-latitude natural vegetation between 50° N and 70° N. The long-term trend of seasonal amplitude increase is 0.311 +/- 0.027 per cent per year, of which sensitivity experiments attribute 45, 29 and 26 per cent to land-use change, climate variability and change, and increased productivity due to CO2 fertilization, respectively. Vegetation growth was earlier by one to two weeks, as measured by the mid-point of vegetation carbon uptake, and took up 0.5 petagrams more carbon in July, the height of the growing season, during 2001-2010 than in 1961

  2. Agricultural green revolution as a driver of increasing atmospheric CO2 seasonal amplitude

    SciTech Connect

    Zeng, Ning; Zhao, Fang; Collatz, George; Kalnay, Eugenia; Salawitch, Ross J.; West, Tristram O.; Guanter, Luis

    2014-11-20

    The atmospheric carbon dioxide (CO2) record displays a prominent seasonal cycle that arises mainly from changes in vegetation growth and the corresponding CO2 uptake during the boreal spring and summer growing seasons and CO2 release during the autumn and winter seasons. The CO2 seasonal amplitude has increased over the past five decades, suggesting an increase in Northern Hemisphere biospheric activity. It has been proposed that vegetation growth may have been stimulated by higher concentrations of CO2 as well as by warming in recent decades, but such mechanisms have been unable to explain the full range and magnitude of the observed increase in CO2 seasonal amplitude. Here we suggest that the intensification of agriculture (the Green Revolution, in which much greater crop yield per unit area was achieved by hybridization, irrigation and fertilization) during the past five decades is a driver of changes in the seasonal characteristics of the global carbon cycle. Our analysis of CO2 data and atmospheric inversions shows a robust 15 per cent long-term increase in CO2 seasonal amplitude from 1961 to 2010, punctuated by large decadal and interannual variations. Using a terrestrial carbon cycle model that takes into account high-yield cultivars, fertilizer use and irrigation, we find that the long-term increase in CO2 seasonal amplitude arises from two major regions: the mid-latitude cropland between 256N and 606N and the high-latitude natural vegetation between 506N and 706 N. The long-term trend of seasonal amplitude increase is 0.311 ± 0.027 percent per year, of which sensitivity experiments attribute 45, 29 and 26 per cent to land-use change, climate variability and change, and increased productivity due to CO2 fertilization, respectively. Vegetation growth was earlier by one to two weeks, as measured by the mid-point of vegetation carbon uptake, and took up 0.5 petagrams more carbon in July, the height of the growing season, during 2001–2010 than in 1961–1970

  3. Population genetics of freeze tolerance among natural populations of Populus balsamifera across the growing season.

    PubMed

    Menon, Mitra; Barnes, William J; Olson, Matthew S

    2015-08-01

    Protection against freeze damage during the growing season influences the northern range limits of plants. Freeze tolerance and freeze avoidance are the two major freeze resistance strategies. Winter survival strategies have been extensively studied in perennials, but few have addressed them and their genetic basis during the growing season. We examined intraspecific phenotypic variation in freeze resistance of Populus balsamifera across latitude and the growing season. To investigate the molecular basis of this variation, we surveyed nucleotide diversity and examined patterns of gene expression in the poplar C-repeat binding factor (CBF) gene family. Foliar freeze tolerance exhibited latitudinal and seasonal variation indicative of natural genotypic variation. CBF6 showed signatures of recent selective sweep. Of the 46 SNPs surveyed across the six CBF homologs, only CBF2_619 exhibited latitudinal differences consistent with increased freeze tolerance in the north. All six CBF genes were cold inducible, but showed varying patterns of expression across the growing season. Some Poplar CBF homologs exhibited patterns consistent with historical selection and clinal variation in freeze tolerance documented here. However, the CBF genes accounted for only a small amount of the variation, indicating that other genes in this and other molecular pathways likely play significant roles in nature. PMID:25809016

  4. Time constraints in temperate-breeding species: influence of growing season length on reproductive strategies

    USGS Publications Warehouse

    Gurney, K. E. B.; Clark, Russell G.; Slattery, Stuart; Smith-Downey, N. V.; Walker, Jordan I.; Armstrong, L.M.; Stephens, S.E.; Petrula, Michael J.; Corcoran, R.M.; Martin, K.; Degroot, K.A.; Brook, Rodney W.; Afton, Alan; Cutting, K.; Warren, J.M.; Fournier, M.; Koons, David N.

    2011-01-01

    Organisms that reproduce in temperate regions have limited time to produce offspring successfully, and this constraint is expected to be more pronounced in areas with short growing seasons. Information concerning how reproductive ecology of endotherms might be influenced by growing season length (GSL) is rare, and species that breed over a broad geographic range provide an opportunity to study the effects of time constraints on reproductive strategies. We analyzed data from a temperate-breeding bird, the lesser scaup Aythya affinis; hereafter scaup, collected at eight sites across a broad gradient of GSL to evaluate three hypotheses related to reproductive compensation in response to varying time constraints. Clutch initiation date in scaup was unaffected by GSL and was unrelated to latitude; spring thaw dates had a marginal impact on timing of breeding. Clutch size declined during the nesting season, as is reported frequently in bird species, but was also unaffected by GSL. Scaup do not appear to compensate for shorter growing seasons by more rapidly reducing clutch size. This study demonstrates that this species is remarkably consistent in terms of timing of breeding and clutch size, regardless of growing season characteristics. Such inflexibility could make this species particularly sensitive to environmental changes that affect resource availabilities.

  5. Time constraints in temperate-breeding species: Influence of growing season length on reproductive strategies

    USGS Publications Warehouse

    Gurney, K. E. B.; Clark, R.G.; Slattery, S.M.; Smith-Downey, N. V.; Walker, J.; Armstrong, L.M.; Stephens, S.E.; Petrula, M.; Corcoran, R.M.; Martin, K.H.; Degroot, K.A.; Brook, Rodney W.; Afton, A.D.; Cutting, K.; Warren, J.M.; Fournier, M.; Koons, D.N.

    2011-01-01

    Organisms that reproduce in temperate regions have limited time to produce offspring successfully, and this constraint is expected to be more pronounced in areas with short growing seasons. Information concerning how reproductive ecology of endotherms might be influenced by growing season length (GSL) is rare, and species that breed over a broad geographic range provide an opportunity to study the effects of time constraints on reproductive strategies. We analyzed data from a temperate-breeding bird, the lesser scaup Aythya affinis; hereafter scaup, collected at eight sites across a broad gradient of GSL to evaluate three hypotheses related to reproductive compensation in response to varying time constraints. Clutch initiation date in scaup was unaffected by GSL and was unrelated to latitude; spring thaw dates had a marginal impact on timing of breeding. Clutch size declined during the nesting season, as is reported frequently in bird species, but was also unaffected by GSL. Scaup do not appear to compensate for shorter growing seasons by more rapidly reducing clutch size. This study demonstrates that this species is remarkably consistent in terms of timing of breeding and clutch size, regardless of growing season characteristics. Such inflexibility could make this species particularly sensitive to environmental changes that affect resource availabilities. ?? 2011 The Authors. Ecography ?? 2011 Ecography.

  6. An overview of crop growing condition monitoring in China agriculture remote sensing monitoring system

    NASA Astrophysics Data System (ADS)

    Huang, Qing; Zhou, Qing-bo; Zhang, Li

    2009-07-01

    China is a large agricultural country. To understand the agricultural production condition timely and accurately is related to government decision-making, agricultural production management and the general public concern. China Agriculture Remote Sensing Monitoring System (CHARMS) can monitor crop acreage changes, crop growing condition, agriculture disaster (drought, floods, frost damage, pest etc.) and predict crop yield etc. quickly and timely. The basic principles, methods and regular operation of crop growing condition monitoring in CHARMS are introduced in detail in the paper. CHARMS can monitor crop growing condition of wheat, corn, cotton, soybean and paddy rice with MODIS data. An improved NDVI difference model was used in crop growing condition monitoring in CHARMS. Firstly, MODIS data of every day were received and processed, and the max NDVI values of every fifteen days of main crop were generated, then, in order to assessment a certain crop growing condition in certain period (every fifteen days, mostly), the system compare the remote sensing index data (NDVI) of a certain period with the data of the period in the history (last five year, mostly), the difference between NDVI can indicate the spatial difference of crop growing condition at a certain period. Moreover, Meteorological data of temperature, precipitation and sunshine etc. as well as the field investigation data of 200 network counties were used to modify the models parameters. Last, crop growing condition was assessment at four different scales of counties, provinces, main producing areas and nation and spatial distribution maps of crop growing condition were also created.

  7. Determination of Spring Onset and Growing Season Duration using Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Min, Q.; Lin, Bing

    2006-01-01

    An integrated approach to retrieve microwave emissivity difference vegetation index (EDVI) over land regions has been developed from combined multi-platform/multi-sensor satellite measurements, including SSM/I measurements. A possible relationship of the remotely sensed EDVI and the leaf physiology of canopy is exploited at the Harvard Forest site for two growing seasons. This study finds that the EDVI is sensitive to leaf development through vegetation water content of the crown layer of the forest canopy, and has demonstrated that the spring onset and growing season duration can be determined accurately from the time series of satellite estimated EDVI within uncertainties about 3 and 7 days for spring onsets and growing season duration, respectively, compared to in-situ observations. The leaf growing stage may also be quantitatively monitored by a normalized EDVI. Since EDVI retrievals from satellite are generally possible during both daytime and nighttime under non-rain conditions, the EDVI technique studied here may provide higher temporal resolution observations for monitoring the onset of spring and the duration of growing season compared to currently operational satellite methods.

  8. The effect of timing of growing season drought on flowering of a dominant C4 grass.

    PubMed

    Dietrich, John D; Smith, Melinda D

    2016-06-01

    Timing of precipitation is equally important as amount for determining ecosystem function, especially aboveground net primary productivity (ANPP), in a number of ecosystems. In tallgrass prairie of the Central Plains of North America, grass flowering stalks of dominant C4 grasses, such as Andropogon gerardii, can account for more than 70 % of ANPP, or almost none of it, as the number of flowering stalks produced is highly variable. Although growing season precipitation amount is important for driving variation in flowering stalk production, it remains unknown whether there are critical periods within the growing season in which sufficient rainfall must occur to allow for flowering. The effect of timing of rainfall deficit (drought) on flowering of A. gerardii, was tested by excluding rainfall during three periods within the growing season (starting in mid-April, mid-May and mid-June). Mid-summer drought (starting in mid-June) strongly reduced the flowering rate (e.g., density and biomass) of A. gerardii (e.g., as high as 94 % compared to the control), suggesting flowering is highly sensitive to precipitation at this time. This effect appeared to be related to plant water status at the time of flowering stalk initiation, rather than an indirect consequence of reduced C assimilation. Our results suggest that increased frequency of growing season drought forecast with climate change could reduce sexual reproduction in this dominant grass species, particularly if it coincides with timing of flowering stalk initiation, with important implications for ecosystem functioning. PMID:26886131

  9. Fertilizer Application Timing Influences Greenhouse Gas Fluxes Over a Growing Season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microbial production and consumption of greenhouse gases (GHG) at the soil surface is influenced by temperature and nutrients, so effects of nutrient application on GHG fluxes should be greater as conditions warm during the growing season. We designed a replicated (n=5) field experiment to test for...

  10. USDA Cranberry Entomology Laboratory (CEL) research priorities in the 2016 growing season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research priorities during the 2016 growing season will be focused on 1) discovery and screening of native WI nematodes as bio-control agents, and 2) continued refinement of the drone-deployed mating disruption system. Extramural funding will be needed for both, and the degree of funding will dictat...

  11. Phosphorus Dynamics in Amended Soils During the Growing Season: II. Ligand Exchange and Mineralization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field study was conducted near Bushland, TX to evaluate changes in phosphorus (P) pools in soils amended with cattle manure and monoammonium phosphate (MAP) throughout a single growing season. Unfertilized checks were included for P extractability comparisons. Grain sorghum (Sorghum bicolor (L.)...

  12. Impacts of climate change on corn yield and the length of corn growing season in U.S. Corn Belt

    NASA Astrophysics Data System (ADS)

    Niyogi, D.; Liu, X.; Takle, E. S.; Anderson, C.; Andresen, J.; Alagarswamy, G.; Gramig, B. M.; Doering, O.

    2015-12-01

    This study is a result of a USDA sponsored project titled Useful to Usable (U2U): "Transforming Climate Variability and Change Information for Cereal Crop Producers". The objective of this project is to improve farm resilience and profitability in the U.S. Corn Belt region by transforming existing meteorological dataset into usable knowledge and tools for the agricultural community. In this study, we conducted the Hybrid-Maize corn growth simulation model at 18 sites across the U.S. Corn Belt with 5 CMIP5 (Coupled Model Intercomparison Project) climate models. The crop model was running for two time periods: 1981-2010 ('current') and 2041-2070 ('future'). We also developed a "delta" method, which combines the current climate variability with the "mean" model projected climate change. The results indicate that under the 'future' climate, growing degree days (GDD) projected corn growing season (from planting date reach to maturity required GDD) are shortened due to the increasing of mean temperature. Compare to the contemporary simulations, the shorter growing season under "future" scenario brings lower attainable yields if farmers using the same cultivar. This presentation will focus on the details about the model simulations, the interactive process employed in developing the simulations, the implications of the results, the uncertainties, and the lessons learned.

  13. Mutation at the circadian clock gene EARLY MATURITY 8 adapts domesticated barley (Hordeum vulgare) to short growing seasons

    PubMed Central

    Faure, Sebastien; Turner, Adrian S.; Gruszka, Damian; Christodoulou, Vangelis; Davis, Seth J.; von Korff, Maria; Laurie, David A.

    2012-01-01

    The circadian clock is an autonomous oscillator that produces endogenous biological rhythms with a period of about 24 h. This clock allows organisms to coordinate their metabolism and development with predicted daily and seasonal changes of the environment. In plants, circadian rhythms contribute to both evolutionary fitness and agricultural productivity. Nevertheless, we show that commercial barley varieties bred for short growing seasons by use of early maturity 8 (eam8) mutations, also termed mat-a, are severely compromised in clock gene expression and clock outputs. We identified EAM8 as a barley ortholog of the Arabidopsis thaliana circadian clock regulator EARLY FLOWERING3 (ELF3) and demonstrate that eam8 accelerates the transition from vegetative to reproductive growth and inflorescence development. We propose that eam8 was selected as barley cultivation moved to high-latitude short-season environments in Europe because it allowed rapid flowering in genetic backgrounds that contained a previously selected late-flowering mutation of the photoperiod response gene Ppd-H1. We show that eam8 mutants have increased expression of the floral activator HvFT1, which is independent of allelic variation at Ppd-H1. The selection of independent eam8 mutations shows that this strategy facilitates short growth-season adaptation and expansion of the geographic range of barley, despite the pronounced clock defect. PMID:22566625

  14. Spatial variability in UV radiation during the growing season across the continental USA

    NASA Astrophysics Data System (ADS)

    Grant, R. H.; Slusser, J. R.

    A major limitation in predicting the ultraviolet-B irradiance on humans, plant leaves and flowers and aquatic organisms is the difficulty in estimating exposure. This study analyzes the spatial variability in the daily exposure of narrow band 300nm and 368nm and broadband 290-315nm (UVB) solar radiation between twelve paired locations in the United States Department of Agriculture (USDA) UVB Climate Network over two summer growing seasons (May through August of 2000 and 2001). The spatial correlation of the UVB, 300nm and 368nm daily exposures between locations was approximately 0.7 to 0.8 for spacing distances of 100km. The 300nm daily exposure was typically more highly correlated between locations than the 368nm daily exposure. Both the diffuse and direct beam components to the 300nm daily exposure were similarly correlated with distance between locations. The 368nm diffuse component of the daily exposures was less correlated with distance than the direct beam component, limiting the ability to interpolate daily exposures from measurement locations. In general the variability in daily exposures of UVB in the USDA UVB Climate Network is too large to interpolate daily exposures of solar radiation, with estimated 300nm, 368nm and broadband UVB errors at one-half the mean station spacing of the USDA Network of 22%, 21% and 16% respectively. More accurate interpolations of UVB exposure from this network will require either the incorporation of cloud cover variability from satellite imagery for daily exposure or the use of longer periods of accumulated exposure.

  15. Enhanced winter soil frost reduces methane emission during the subsequent growing season in a boreal peatland.

    PubMed

    Zhao, Junbin; Peichl, Matthias; Nilsson, Mats B

    2016-02-01

    Winter climate change may result in reduced snow cover and could, consequently, alter the soil frost regime and biogeochemical processes underlying the exchange of methane (CH4 ) in boreal peatlands. In this study, we investigated the short-term (1-3 years) vs. long-term (11 years) effects of intensified winter soil frost (induced by experimental snow exclusion) on CH4 exchange during the following growing season in a boreal peatland. In the first 3 years (2004-2006), lower CH4 emissions in the treatment plots relative to the control coincided with delayed soil temperature increase in the treatment plots at the beginning of the growing season (May). After 11 treatment years (in 2014), CH4 emissions were lower in the treatment plots relative to the control over the entire growing season, resulting in a reduction in total growing season CH4 emission by 27%. From May to July 2014, reduced sedge leaf area coincided with lower CH4 emissions in the treatment plots compared to the control. From July to August, lower dissolved organic carbon concentrations in the pore water of the treatment plots explained 72% of the differences in CH4 emission between control and treatment. In addition, greater Sphagnum moss growth in the treatment plots resulted in a larger distance between the moss surface and the water table (i.e., increasing the oxic layer) which may have enhanced the CH4 oxidation potential in the treatment plots relative to the control in 2014. The differences in vegetation might also explain the lower temperature sensitivity of CH4 emission observed in the treatment plots relative to the control. Overall, this study suggests that greater soil frost, associated with future winter climate change, might substantially reduce the growing season CH4 emission in boreal peatlands through altering vegetation dynamics and subsequently causing vegetation-mediated effects on CH4 exchange. PMID:26452333

  16. Seasonal Variations of Nitrate Concentrations In Agricultural Catchments

    NASA Astrophysics Data System (ADS)

    Martin, C.; Aquilina, L.; Gascuel-Odoux, C.; Molénat, J.; Ruiz, L.

    Nitrate concentrations in streams of agricultural catchments with impervious bedrock often present an interannual variability (due to landuse changes) and a seasonal one. Usually seasonal variations are characterised by high concentrations in winter and low in summer. Some catchments may present intermediate or inverse cycles (high con- centrations in summer). Two hypothesis to explain classical variations of nitrate con- centrations in streams exist: (i) the availibility of nitrate in the soil for leaching and (ii) the temporal variations of the nitrate-rich shallow groundwater. The aim of this study is to explain the occurence of classical or inverse scheme of seasonal variations by testing these two existing hypothesis and proposing an alternative one for inverse cycles. Two catchments with different seasonal variations (KERRIEN catchment : normal cycle, and KERBERNEZ catchment : inverse cycle), located in the South Western French Brittany, were instrumented in 2001 with a set of 22 piezometers in- stalled at different depths and located along the hillslope. The water table dynamic and chemestry (nitrate, chloride, carbon, Rare Earth Elements,...) had been measured weekly during one year. The shallow groundwater of the Kerrien catchment is char- acterised by two lateral domains with a temporal stability of concentrations : the bot- tom land, constantly denitrified, and the upper domain with nitrate concentrations around 60 mg.L(-1) . The Kerbernez catchment is characterised by two vertical domains with a temporal rise of concentrations : the upper domain with nitrate concen- trations around 60 mg.L(-1) , as the Kerrien catchment, and a deeper compartment, with concentrations excedeed 100 to 120 mg.L(-1) of nitrate. On the Kerrien catchment, the classical cycle is due to the most important contribution of the shal- low groundwater in winter. The inverse cycle of the Kerbernez catchment may be due to the most important contribution of the deep compartment in

  17. Predicting Future Temperate and Boreal of Growing Season Start With a Land Surface Model

    NASA Astrophysics Data System (ADS)

    Kaduk, J.

    2008-12-01

    Controlled ecological experiments show that temperate and boreal trees require chilling in winter for rapid leaf out in spring. If the amount of chilling falls below a species specific threshold then an exponentially increasing amount of warming is required to initiate leaf out - potentially actually delaying it in a future warmer climate. The boreal areas could be particularly affected as climate predictions indicate strong warming in these regions. Moreover, currently a large part of the land carbon sink is located in temperate and boreal regions and a changing growing season start might have a large impact on this important sink. Warming-chilling models for green-up, which have been calibrated with remotely sensed normalized difference vegetation index from the years 1983-1995, indicate that in future the chilling requirements reduce the rate of advance of the start of the growing season to earlier times compared to advance rates in the last two decades. Climate scenarios with large warming (IPCC A2 scenarios) show lower advance rates of green- up to earlier times than predictions with a smaller warming (B1 scenarios) due to the reduced chilling in high warming scenarios. When incorporated into a coupled land-surface carbon cycle model based on JULES (the Joint-UK-Land Environment Simulator) the chilling requirements lead to a early growing season photosynthetic carbon up that is correspondingly lower than in simulations where the start of the growing season as simply modelled as responding to warming only. Thus the phenological response in effect provides a positive feedback to global warming.

  18. Comparison of Phenology Models for Predicting the Onset of Growing Season over the Northern Hemisphere

    PubMed Central

    Fu, Yang; Zhang, Haicheng; Dong, Wenjie; Yuan, Wenping

    2014-01-01

    Vegetation phenology models are important for examining the impact of climate change on the length of the growing season and carbon cycles in terrestrial ecosystems. However, large uncertainties in present phenology models make accurate assessment of the beginning of the growing season (BGS) a challenge. In this study, based on the satellite-based phenology product (i.e. the V005 MODIS Land Cover Dynamics (MCD12Q2) product), we calibrated four phenology models, compared their relative strength to predict vegetation phenology; and assessed the spatial pattern and interannual variability of BGS in the Northern Hemisphere. The results indicated that parameter calibration significantly influences the models' accuracy. All models showed good performance in cool regions but poor performance in warm regions. On average, they explained about 67% (the Growing Degree Day model), 79% (the Biome-BGC phenology model), 73% (the Number of Growing Days model) and 68% (the Number of Chilling Days-Growing Degree Day model) of the BGS variations over the Northern Hemisphere. There were substantial differences in BGS simulations among the four phenology models. Overall, the Biome-BGC phenology model performed best in predicting the BGS, and showed low biases in most boreal and cool regions. Compared with the other three models, the two-phase phenology model (NCD-GDD) showed the lowest correlation and largest biases with the MODIS phenology product, although it could catch the interannual variations well for some vegetation types. Our study highlights the need for further improvements by integrating the effects of water availability, especially for plants growing in low latitudes, and the physiological adaptation of plants into phenology models. PMID:25279567

  19. Comparison of phenology models for predicting the onset of growing season over the Northern Hemisphere.

    PubMed

    Fu, Yang; Zhang, Haicheng; Dong, Wenjie; Yuan, Wenping

    2014-01-01

    Vegetation phenology models are important for examining the impact of climate change on the length of the growing season and carbon cycles in terrestrial ecosystems. However, large uncertainties in present phenology models make accurate assessment of the beginning of the growing season (BGS) a challenge. In this study, based on the satellite-based phenology product (i.e. the V005 MODIS Land Cover Dynamics (MCD12Q2) product), we calibrated four phenology models, compared their relative strength to predict vegetation phenology; and assessed the spatial pattern and interannual variability of BGS in the Northern Hemisphere. The results indicated that parameter calibration significantly influences the models' accuracy. All models showed good performance in cool regions but poor performance in warm regions. On average, they explained about 67% (the Growing Degree Day model), 79% (the Biome-BGC phenology model), 73% (the Number of Growing Days model) and 68% (the Number of Chilling Days-Growing Degree Day model) of the BGS variations over the Northern Hemisphere. There were substantial differences in BGS simulations among the four phenology models. Overall, the Biome-BGC phenology model performed best in predicting the BGS, and showed low biases in most boreal and cool regions. Compared with the other three models, the two-phase phenology model (NCD-GDD) showed the lowest correlation and largest biases with the MODIS phenology product, although it could catch the interannual variations well for some vegetation types. Our study highlights the need for further improvements by integrating the effects of water availability, especially for plants growing in low latitudes, and the physiological adaptation of plants into phenology models. PMID:25279567

  20. Growing Degree Vegetation Production Index (GDVPI): A Novel and Data-Driven Approach to Delimit Season Cycles

    NASA Astrophysics Data System (ADS)

    Graham, W. D.; Spruce, J.; Ross, K. W.; Gasser, J.; Grulke, N.

    2014-12-01

    Growing Degree Vegetation Production Index (GDVPI) is a parametric approach to delimiting vegetation seasonal growth and decline cycles using incremental growing degree days (GDD), and NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) 8-day composite cumulative integral data. We obtain a specific location's daily minimum and maximum temperatures from the nearest National Oceanic and Atmospheric Administration (NOAA) weather stations posted on the National Climate Data Center (NCDC) Climate Data Online (CDO) archive and compute GDD. The date range for this study is January 1, 2000 through December 31, 2012. We employ a novel process, a repeating logistic product (RLP), to compensate for short-term weather variability and data drops from the recording stations and fit a curve to the median daily GDD values, adjusting for asymmetry, amplitude, and phase shift that minimize the sum of squared errors when comparing the observed and predicted GDD. The resulting curve, here referred to as the surrogate GDD, is the time-temperature phasing parameter used to convert Cartesian NDVI values into polar coordinate pairs, multiplying the NDVI values as the radial by the cosine and sine of the surrogate GDD as the angular. Depending on the vegetation type and the original NDVI curve, the polar NDVI curve may be nearly circular, kidney-shaped, or pear-shaped in the case of conifers, deciduous, or agriculture, respectively. We examine the points of tangency about the polar coordinate NDVI curve, identifying values of 1, 0, -1, or infinity, as each of these represent natural inflection points. Lines connecting the origin to each tangent point illustrate and quantify the parametrically segmentation of the growing season based on the GDD and NDVI ostensible dependency. Furthermore, the area contained by each segment represents the apparent vegetation production. A particular benefit is that the inflection points are determined

  1. Evaluating the vegetation growing season changes in the arid region of northwestern China

    NASA Astrophysics Data System (ADS)

    Wang, Yanfang; Shen, Yanjun; Sun, Fubao; Chen, Yaning

    2014-11-01

    Temperature has long been accepted as the major controlling factor in determining vegetation phenology in the middle and higher latitudes. The influence of water availability is often overlooked even in arid and semi-arid environments. We compared vegetation phenology metrics derived from both in situ temperature and satellite-based normalized difference vegetation index (NDVI) observations from 1982 to 2006 by an example of the arid region of northwestern China. From the satellite-based results, it was found the start of the growing season (SOS) advanced by 0.37 days year-1 and the end of the growing season (EOS) delayed by 0.61 days year-1 in Southern Xinjiang over 25 years. In the Tianshan Mountains, the SOS advanced by 0.35 days year-1 and the EOS delayed by 0.31 days year-1. There were almost no changes in Northern Xinjiang. Compared with satellite-based results, those estimates based on temperature contain less details of spatial variability of vegetation phenology. Interestingly, they show different and at times reversed spatial patterns from the satellite results arising from water limitation. Phenology metrics derived from temperature and NDVI conclude that water limitation of onset of the growing season is more severe than the cessation. Phenology spatial patterns of four oases in Southern Xingjiang show that, on average, there is a delay of the SOS of 1.6 days/10 km of distance from the mountain outlet stations. Our results underline the importance of water availability in determining the vegetation phenology in arid regions and can lead to important consequences in interpreting the possible change of vegetation phenology with climate.

  2. Does the start and end of the biological growing season respond independently to a changing climate?

    NASA Astrophysics Data System (ADS)

    Bolmgren, Kjell

    2016-04-01

    Adaptation of the biological growing season to a changing climatic requires that plants can adapt their phenology plastically or genetically to new conditions. Physiological and evolutionary constraints may, however, hamper such adaptations. Here, we study correlations between leafing out and autumn coloration phenology, that is, the start and end of the green growing season. In temperate, deciduous tree species the period with green leaves is more or less the same as the individual leaf's life span. General plant ecological strategy schemes suggest that the individual leaf's life span is one of the major dimensions evolutionary associated with other leaf and plant characteristics, including expensive investments in leaf nutrient content and leaf morphology. Leaf life span is thus considered highly conserved within evolutionary lineages. At the same time, local adaptation of leaf phenology to the length of the climatic growing season is common, both when it comes to leafing out cues and autumn senescence cues, suggesting that there are strong selection pressures and adaptability (plastic and/or genetic) to make use of the climatically defined growing season. We used a data set from a Swedish, national phenology network where volunteer observers recorded the start of leafing out defined as 'when the tree looks green from a distance' and the start of autumn leaf coloration as 'when 1/3 of the tree canopy had attained autumn colors'. In the subset used observations were made at 489 sites/farms between 1873-1922. We only included data when the observer at a site and year had recorded both spring leafing and autumn leaf coloration phenology on the same species. In total, the data set comprised 25'099 observations of 17 species. As the participants in the phenology monitoring network were volunteers, the data matrix has lots of missing data and unbalanced representation from different sites. We used linear mixed model analyses, including year as random factor, to analyse

  3. Migrant and Seasonal Agricultural Areas. Methodology for Designating High Impact.

    ERIC Educational Resources Information Center

    HCR, Washington, DC.

    This report describes a method to estimate the number of migrant and seasonal farmworkers present in a prescribed area during crop harvest, and to pinpoint areas of high need for health and social services. The collection of health clinic and federal program data on migrant and seasonal farmworkers in Florida, northwestern Ohio, and Maryland's…

  4. Growing season ecosystem and leaf-level gas exchange of an exotic and native semiarid bunchgrass.

    PubMed

    Hamerlynck, Erik P; Scott, Russell L; Moran, M Susan; Keefer, Timothy O; Huxman, Travis E

    2010-07-01

    The South African grass, Lehmann lovegrass (Eragrostis lehmanniana), may alter ecosystem processes across extensive semiarid grasslands and savannahs of western North America. We compared volumetric soil moisture (theta), total and green tissue leaf area index (LAI), ecosystem (i.e. whole-plant and soil), and leaf-level gas exchange of Lehmann lovegrass and the native bush muhly (Muhlenbergia porteri) over the 2008 monsoon season in a semiarid savanna in southern Arizona, USA, to see if these were consistent with high productivity associated with lovegrass invasive success. theta across 0-5 and 0-25 cm was higher while evapotranspiration (ET) was similar between lovegrass and bush muhly plots, except shortly after rainfall, when ET was 32-81% higher in lovegrass plots. Lehmann lovegrass had lower, quickly developing LAI with greater leaf proportions than bush muhly. When early season theta was high, net ecosystem CO(2) exchange (NEE) was similar, but as storm frequency and theta declined, NEE was more negative in lovegrass (-0.69 to -3.00 micromol m(-2) s(-1)) than bush muhly (+1.75 to -1.55 micromol m(-2) s(-1)). Ecosystem respiration (R (eco)) responded quickly to monsoon onset and late-season rains, and was lower in lovegrass (2.44-3.74 micromol m(-2) s(-1)) than bush muhly (3.60-5.3 micromol m(-2) s(-1)) across the season. Gross ecosystem photosynthesis (GEP) was greater in Lehmann lovegrass, concurrent with higher leaf-level photosynthesis and stomatal conductance. We conclude that canopy structure facilitates higher theta under Lehmann lovegrass, reducing phenological constraints and stomatal limitations to whole-plant carbon uptake through the short summer monsoon growing season. PMID:20063168

  5. Season of testing and its effect on feed intake and efficiency in growing beef cattle.

    PubMed

    Mujibi, F D N; Moore, S S; Nkrumah, D J; Wang, Z; Basarab, J A

    2010-12-01

    This study sought to assess whether residual feed intake (RFI) calculated by regressing feed intake (DMI) on growth rate (ADG) and metabolic mid-BW in 3 different ways led to similar estimates of genetic parameters and variance components for young growing cattle tested for feed intake in fall and winter seasons. A total of 378 beef steers in 5 cohorts were fed a typical high energy feedlot diet and had free-choice access to feed and water. Feed intake data were collected in fall or winter seasons. Climate data were obtained from the University of Alberta Kinsella meteorological station and Vikings AGCM station. Individual animal RFI was obtained by either fitting a regression model to each test group separately (RFI(C)), fitting a regression model to pooled data consisting of all cohorts but including test group as a fixed effect (RFI(O)), or fitting a regression to pooled data with test group as a fixed effect but within seasonal (fall-winter or winter-spring) groups (RFI(S)). Two animal models (M1 and M2) that differed by the inclusion of fixed effects of test group or season, respectively, were used to evaluate RFI measurements. Feed intake was correlated with air temperature, relative humidity, solar radiation, and wind speed (-0.26, 0.23, 0.30, -0.14 for fall-winter and 0.31, -0.04, 0.14, 0.16 for winter-spring, respectively), but the nature and magnitude of the correlations were different for the 2 seasons. Single trait direct heritability, model likelihood, direct genetic variance, and EBV accuracy estimates were greatest for RFI(C) and least for RFI(O) for both M1 and M2 models. A significant genetic correlation was also observed between RFI(O) and ADG, but not for RFI(C) and RFI(S). Including a season effect (M2) in the genetic evaluation of RFI(O) resulted in the smallest heritability, model LogL, EBV accuracy, and largest residual variance estimates. These results, though not conclusive, suggest a possible effect of seasonality on feed intake and thus

  6. Higher northern latitude normalized difference vegetation index and growing season trends from 1982 to 1999

    NASA Technical Reports Server (NTRS)

    Tucker, C. J.; Slayback, D. A.; Pinzon, J. E.; Los, S. O.; Myneni, R. B.; Taylor, M. G.

    2001-01-01

    Normalized difference vegetation index data from the polar-orbiting National Oceanic and Atmospheric Administration meteorological satellites from 1982 to 1999 show significant variations in photosynthetic activity and growing season length at latitudes above 35 degrees N. Two distinct periods of increasing plant growth are apparent: 1982-1991 and 1992-1999, separated by a reduction from 1991 to 1992 associated with global cooling resulting from the volcanic eruption of Mt. Pinatubo in June 1991. The average May to September normalized difference vegetation index from 45 degrees N to 75 degrees N increased by 9% from 1982 to 1991, decreased by 5% from 1991 to 1992, and increased by 8% from 1992 to 1999. Variations in the normalized difference vegetation index were associated with variations in the start of the growing season of -5.6, +3.9, and -1.7 days respectively, for the three time periods. Our results support surface temperature increases within the same period at higher northern latitudes where temperature limits plant growth.

  7. Growing season net ecosystem CO2 exchange of two desert ecosystems with alkaline soils in Kazakhstan

    PubMed Central

    Li, Longhui; Chen, Xi; van der Tol, Christiaan; Luo, Geping; Su, Zhongbo

    2014-01-01

    Central Asia is covered by vast desert ecosystems, and the majority of these ecosystems have alkaline soils. Their contribution to global net ecosystem CO2 exchange (NEE) is of significance simply because of their immense spatial extent. Some of the latest research reported considerable abiotic CO2 absorption by alkaline soil, but the rate of CO2 absorption has been questioned by peer communities. To investigate the issue of carbon cycle in Central Asian desert ecosystems with alkaline soils, we have measured the NEE using eddy covariance (EC) method at two alkaline sites during growing season in Kazakhstan. The diurnal course of mean monthly NEE followed a clear sinusoidal pattern during growing season at both sites. Both sites showed significant net carbon uptake during daytime on sunny days with high photosynthetically active radiation (PAR) but net carbon loss at nighttime and on cloudy and rainy days. NEE has strong dependency on PAR and the response of NEE to precipitation resulted in an initial and significant carbon release to the atmosphere, similar to other ecosystems. These findings indicate that biotic processes dominated the carbon processes, and the contribution of abiotic carbon process to net ecosystem CO2 exchange may be trivial in alkaline soil desert ecosystems over Central Asia. PMID:24455157

  8. Higher northern latitude normalized difference vegetation index and growing season trends from 1982 to 1999.

    PubMed

    Tucker, C J; Slayback, D A; Pinzon, J E; Los, S O; Myneni, R B; Taylor, M G

    2001-11-01

    Normalized difference vegetation index data from the polar-orbiting National Oceanic and Atmospheric Administration meteorological satellites from 1982 to 1999 show significant variations in photosynthetic activity and growing season length at latitudes above 35 degrees N. Two distinct periods of increasing plant growth are apparent: 1982-1991 and 1992-1999, separated by a reduction from 1991 to 1992 associated with global cooling resulting from the volcanic eruption of Mt. Pinatubo in June 1991. The average May to September normalized difference vegetation index from 45 degrees N to 75 degrees N increased by 9% from 1982 to 1991, decreased by 5% from 1991 to 1992, and increased by 8% from 1992 to 1999. Variations in the normalized difference vegetation index were associated with variations in the start of the growing season of -5.6, +3.9, and -1.7 days respectively, for the three time periods. Our results support surface temperature increases within the same period at higher northern latitudes where temperature limits plant growth. PMID:11769318

  9. Temporal evolution of the macropore network and saturated hydraulic conductivity in an arable, clayey topsoil during one growing season

    NASA Astrophysics Data System (ADS)

    Sandin, Maria; Köstel, Johannes; Jarvis, Nicholas; Larsbo, Mats

    2015-04-01

    Soil macropore networks and thus hydraulic properties at and close to saturation vary considerably with time, as a result of the dynamic nature of a diverse range of interacting soil structure-forming and degrading factors such as tillage and traffic events, faunal and plant root activity, swell/shrink arising from wetting and drying cycles, freeze-thaw etc. These properties are nevertheless treated as constants in most hydrological modelling studies. This is mostly justified by a lack of understanding of the processes driving these changes. Temporal variations of saturated and near-saturated hydraulic conductivity have been studied in the field (e.g. by tension disc infiltrometer), but these measurements only indirectly reflect the characteristics of the macropore network. In this study, we used non-destructive X-ray tomography to investigate the temporal changes in the macropore network characteristics occurring in the harrowed layer of a conventionally-tilled agricultural field over one growing season. Undisturbed soil cores (60-70 mm height, 68 mm diameter) were sampled on five different occasions. Changes in the geometric and topological properties of the X-ray imaged macropore system (voxel resolution = 120 µm) were compared with variations in saturated hydraulic conductivity measured on the same samples. Image analysis showed that total porosity, specific surface area, average pore diameter and the connectivity of the pore system in the uppermost 60-70 mm of ploughed and harrowed soil decreased from the first sampling occasion shortly after seedbed preparation and sowing until the middle of the growing season after which it slightly increased again. Separate analysis of the total porosity of the top 5 mm showed a marked decrease between the first two sampling occasions, followed by a gradual increase. Despite these structural changes in the macropore system, saturated hydraulic conductivity was only weakly correlated with macropore network characteristics.

  10. Using knowledge of agricultural practices to enhance through-the-season interpretation of Landsat data

    NASA Technical Reports Server (NTRS)

    Malila, W. A.; Pestre, C. R.

    1984-01-01

    Landsat data contain features that can be interpreted to produce information about crops, in support of crop estimation procedures. This paper considers ways in which detailed knowledge of agricultural practices and events might increase and improve the utilization of Landsat data in both the predictive and observational or measurement components of such procedures. Landsat observables related to agricultural practices and events throughout the cropping season are listed. Agricultural fields are identified as the preferred observational units for incorporating refined agricultural understanding, such as crop rotation patterns, into machine procedures. Uses of Landsat data from both prior seasons and the current season are considered, as is use of predictive models of crop appearance. The investigation of knowledge engineering systems tailored to through-the-season estimation problems is recommended for long range development.

  11. Trends toward an earlier peak of the growing season in Northern Hemisphere mid-latitudes.

    PubMed

    Xu, Chongyang; Liu, Hongyan; Williams, A Park; Yin, Yi; Wu, Xiuchen

    2016-08-01

    Changes in peak photosynthesis timing (PPT) could substantially change the seasonality of the terrestrial carbon cycle. Spring PPT in dry regions has been documented for some individual plant species on a stand scale, but both the spatio-temporal pattern of shifting PPT on a continental scale and its determinants remain unclear. Here, we use satellite measurements of vegetation greenness to find that the majority of Northern Hemisphere, mid-latitude vegetated area experienced a trend toward earlier PPT during 1982-2012, with significant trends of an average of 0.61 day yr(-1) across 19.4% of areas. These shifts correspond to increased annual accumulation of growing degree days (GDD) due to warming and are most highly concentrated in the eastern United States and Europe. Earlier mean PPT is generally a trait common among areas with summer temperatures higher than 27.6 ± 2.9 °C, summer precipitation lower than 84.2 ± 41.5 mm, and fraction of cold season precipitation greater than 89.2 ± 1.5%. The trends toward earlier PPT discovered here have co-occurred with overall increases in vegetation greenness throughout the growing season, suggesting that summer drought is not a dominant driver of these trends. These results imply that continued warming may facilitate continued shifts toward earlier PPT and cause these trends to become more pervasive, with important implications for terrestrial carbon, water, nutrient, and energy budgets. PMID:26752300

  12. A multi-refuge study to evaluate the effectiveness of growing-season and dormant-season burns to control cattail

    USGS Publications Warehouse

    Gleason, Robert A.; Tangen, Brian A.; Laubhan, Murray K.; Lor, Socheata

    2012-01-01

    Proliferation of invasive cattails (for example, Typha x glauca, T. angustifolia) is a concern of wetland managers across the country, and numerous methods have been used to control the spatial extent and density of the plant. To date, however, no single method has proven widely or consistently effective at reducing the long-term growth and spread of these species. We performed a multi-refuge study to evaluate the relative effects of growing-season and dormant-season prescribed burns on cattail production and to gain insight on variables such as soil moisture, groundwater, and biomass that affect the efficacy of burning as a control method. Results indicate total cattail cover recovers to pre-burn levels within 1 year regardless of whether the controlled burn was implemented during the growing season or dormant season. Growing-season burns, however, did result in lower aboveground and belowground cattail biomass 1-year post-burn, whereas no significant change in biomass was detected for dormant-season burns. Study results support the premise that burns implemented during the growing season should have a greater effect on nutrient reserves and cattail re-growth. Results from this and other studies suggest long-term research that incorporates multiple management strategies will be required to evaluate the potential of prescribed burning as a method to control cattail.

  13. Microwave remote sensing of short-term droughts during crop growing seasons

    NASA Astrophysics Data System (ADS)

    Yuan, Xing; Ma, Zhuguo; Pan, Ming; Shi, Chunxiang

    2015-06-01

    Severe short-term (monthly to seasonal) droughts frequently occurred over China in recent years, with devastating impacts on crop production. This study assesses the capability of microwave remote sensing in detecting soil moisture (agricultural) droughts over China and in providing early warnings. The 22 year (1992-2013) European Space Agency satellite soil moisture retrievals are compared against the in situ observations at 312 stations in China, the global soil moisture reanalysis, and the observed rainfall deficit. Both the reanalysis and remote sensing products can only detect less than 60% of drought months at in situ station scale, but they capture the interannual variations of short-term drought area at river basin scales quite well. As compared with reanalysis, the passive and merged microwave products have better drought detection over sparsely vegetated regions in northwestern China and the active microwave product with better vegetation penetration works the best in eastern China.

  14. Effects of chronic doses of ozone on loblolly pine: Photosynthetic characteristics in the third growing season

    SciTech Connect

    Sasek, T.W.; Richardson, C.J. )

    1989-09-01

    Gas exchange characteristics of loblolly pine seedlings were measured in the third growing season of ozone fumigations to determine the effects of long-term ozone exposure on photosynthetic capacity. Light and CO{sub 2} response curves indicated significant decreases of 21% and 27%, respectively, in light-saturated and CO{sub 2}-saturated photosynthetic capacities at 2 {times} ambient ozone compared to charcoal-filtered (CF) air, approximately 0.5 {times} ambient ozone. Differences in the response curves suggest changes in light-harvesting and biochemical efficiencies as well as changes in the activity of RuBP carboxylase and the regeneration rate of RuBP. Chlorophyll and carotenoid conditions per unit leaf area were decreased at the high ozone treatment in older flushes. Stomatal resistance limited photosynthesis by about 29% in both CF and 2 {times} ambient ozone treated plants, suggesting that chronic ozone exposure did not affect stomatal control in loblolly pine.

  15. Growing season loss of nitrate at three northeastern hardwood forests: A regional indicator of nitrogen saturation

    SciTech Connect

    Pardo, L.H.; Murdoch, P.E.; Mitchell, M.J.; Driscoll, C.T.; Likens, G.E. )

    1994-06-01

    Nitrogen is typically tightly retained in terrestrial ecosystems in the Northeast. In ecosystems with episodic nitrogen losses, nitrate export during the summer period of high biotic demand remains low. Increasing nitrate loss during the growing season is an early indicator of ecosystems shifting from episodic to chronic nitrogen loss (nitrogen saturation). Studies of nitrogen cycling from Biscuit Brook, Catskills, NY, Huntington Forest, Adirondacks, NY and Hubbard Brook Experimental Forest, White Mountains, NH, showed high nitrate loss at each site during the summer of 1990. This regional pattern many be caused by anthropogenic (higher nitrogen deposition), climatic (temperature and weather interactions), and/or natural (eg. pest outbreaks) disturbance. High nitrate loss causes surface water quality deterioration and may be linked to forest decline. The pattern also demonstrates the need for surface water monitoring on a regional scale to assess the effects of air pollution emissions legislation.

  16. Impacts of intra-seasonal agricultural decision-making and forecast information on maize production in Zambia

    NASA Astrophysics Data System (ADS)

    Tian, D.; Estes, L. D.; Evans, T. P.; Caylor, K. K.; Sheffield, J.; Wood, E. F.

    2015-12-01

    Maize is the most important food staple in sub-Saharan Africa. Climate change and rainfall variability pose great risks on maize production in this region. Intra-seasonal adaptive management combined with more skillful weather forecasts has the potential to improve the resilience of agricultural systems. Our aim is to understand the extent to which within-season agricultural management decisions can mitigate weather risks to maize production, and the degree to which this mitigation varies as a function of when the decision is made and the trajectory of weather. Using Zambia as a test case, we conducted crop-modeling experiments to determine which crop and water management decisions (typical of smallholder farmers) are most effective in mitigating rainfall-driven yield reductions under three precipitation scenarios (below normal, normal, and above normal). Yields were simulated using the DSSAT CERES-Maize model driven by an ensemble of historical weather data. Potential maize yields under different management options were simulated from different forecast points during the growing season, starting at planting and then in successive two-week intervals through the grain-filling period. The yield distributions were constructed as a function of the weather conditions and the management options, with results indicating which decision options provide the most mitigation in relation to a) the particular point in the growing season at which they are made, and b) the potential rainfall scenario. This study will help to understand how smallholder farmers in semi-arid systems may increase their resilience to highly variable weather by using typical within-season management options, and which decisions are most robust to forecast uncertainty.

  17. The net exchange of methane with high Arctic landscapes during the summer growing season

    NASA Astrophysics Data System (ADS)

    St Louis, V. L.; Emmerton, C. A.; Lehnherr, I.; Humphreys, E.; Rydz, E.; Kosolofski, H.

    2014-12-01

    High Arctic landscapes are essentially vast cold deserts interspersed with streams, ponds and wetlands. These landscapes may be important consumers and sources of the greenhouse gas methane (CH4), though few measurements exist from this region. To quantify the flux of CH4 (FCH4) between the atmosphere and high Arctic landscapes on northern Ellesmere Island, Canada, we made static chamber measurements over five and three growing seasons at a desert and wetland, respectively, and eddy covariance (EC) measurements at a wetland in 2012. Chamber measurements revealed that, during the growing season, desert soils consumed CH4 (-1.37±0.06 mg- CH4 m-2 d-1), whereas the wetland margin emitted CH4 (+0.22±0.14 mg- CH4 m-2 d-1). Desert CH4 consumption rates were positively associated with soil temperature among years, and were similar to temperate locations, likely because of suitable landscape conditions for soil gas diffusion. Wetland FCH4 varied closely with stream discharge entering the wetland and hence extent of soil saturation. Landscape-scale FCH4 measured by EC was +1.27±0.18 mg- CH4 m-2 d-1 and varied with soil temperature and carbon dioxide flux. FCH4 measured using EC was higher than using chambers because EC measurements incorporated a larger, more saturated footprint of the wetland. Using EC FCH4 and quantifying the mass of CH4 entering and exiting the wetland in stream water, we determined that methanogenesis within wetland soils was the dominant source of FCH4. Low FCH4 at the wetland was likely due to a shallow organic soil layer, and thus limited carbon resources for methanogens. Considering the prevalence of dry soils in the high Arctic, our results suggest that these landscapes cannot be overlooked as important consumers of atmospheric CH4.

  18. Forest phenology and a warmer climate - Growing season extension in relation to climatic provenance

    SciTech Connect

    Gunderson, Carla A; Edwards, Nelson T; Walker, Ashley V; O'Hara, Keiran H; Campion, Christina M; Hanson, Paul J

    2012-01-01

    Predicting forest responses to warming climates relies on assumptions about niche and temperature sensitivity that remain largely untested. Observational studies have related current and historical temperatures to phenological shifts, but experimental evidence is sparse, particularly for autumn responses. A five-year field experiment exposed four deciduous forest species from contrasting climates (Liquidambar styraciflua, Quercus rubra, Populus grandidentata, and Betula alleghaniensis) to air temperatures 2 and 4 C above ambient controls. Impacts of year-round warming on bud burst (BB), senescence and abscission were evaluated in relation to thermal provenance. Leaves emerged earlier in all species, by an average of 6-9 days at +2 and +4 C. Magnitude of advance varied with species and year, but was larger for the first 2 C increment than the second. The effect of warming increased with early BB, favoring Liquidambar, from the warmest climate, but even BB in northern species advanced, despite temperatures well beyond those of the realized niche. Treatment differences in BB were poorly explained by temperature sums, which increased with treatment. In autumn, chlorophyll was retained an average of 4 and 7 days longer in +2 and +4 C treatments, and abscission delayed by 8 and 13 days. Species differences in autumn responses were marginally significant. Growing seasons in the warmer atmospheres were 6 - 28 days longer, with the least impact in Quercus. Results are compared with a 16-year record of canopy onset and offset in a nearby upland deciduous forest, where BB showed similar responsiveness to spring temperatures (2 - 4 days C-1). Offset dates in the stand tracked August-September temperatures, except when late summer drought caused premature senescence. The common garden-like experimental approach provides evidence that warming alone extends the growing season, at both ends, even if stand-level impacts are complicated by other environmental factors.

  19. Multi-sensor analysis of changing growing season dynamics across northwest North America since 1998

    NASA Astrophysics Data System (ADS)

    Nemani, R.; White, M.; Schwartz, M.; Saatchi, S.; Myneni, R.; Dettinger, M.; Cayan, D.

    2005-12-01

    Changes in Pacific Climate on interannual (ENSO) and decadal time scales (Pacific Decadal Oscillation, PDO)have a strong impact on a variety of biospheric processes over northwest North America, including changes in vegetation phenology, snow hydrology, summer drought and fire frequency, forest growth and crop yields. Though evidence exists for a shift in PDO in 1998, the impact of such a shift on terrestrial ecosystems is not yet known. We used a variety of satellite (AVHRR, SSM/I, GOES) and surface (NWS, SNOTEL, streamflow) networks to characterize changes in climate and ecosystem conditions between 1991-97 and 1998-04. Satellite data show that cooler sea surface temperatures during 1998-04 period led to lower atmospheric water vapor over the North Pacific, which in turn led to lower dewpoint and night minimum temperatures over northwest North America. Such climatic changes were dramatic over spring, leading to a delay in the satellite-derived onset of growing season. Modeled budbreak/flowering phases, based on observed weather data, also show a delay of 4-7 days during 1998-04 compared to 1991-97. The delay in growing season onset after 1998 was further supported by later occurrence of soil thaw and snowmelt. It is probably too early to determine if any of the observed changes are a part of the purported shift in PDO. However if they persist, climate-sensitive sectors such as viticulture, with large expansions in recent years, could face potential problems. Continuous monitoring facilitated by a variety of satellite and ground-based sensors offers an unprecedented, spatio-temporal view of changes as they happen.

  20. Pan-Arctic linkages between snow accumulation and growing-season air temperature, soil moisture and vegetation

    NASA Astrophysics Data System (ADS)

    Luus, K. A.; Gel, Y.; Lin, J. C.; Kelly, R. E. J.; Duguay, C. R.

    2013-11-01

    Arctic field studies have indicated that the air temperature, soil moisture and vegetation at a site influence the quantity of snow accumulated, and that snow accumulation can alter growing-season soil moisture and vegetation. Climate change is predicted to bring about warmer air temperatures, greater snow accumulation and northward movements of the shrub and tree lines. Understanding the responses of northern environments to changes in snow and growing-season land surface characteristics requires: (1) insights into the present-day linkages between snow and growing-season land surface characteristics; and (2) the ability to continue to monitor these associations over time across the vast pan-Arctic. The objective of this study was therefore to examine the pan-Arctic (north of 60° N) linkages between two temporally distinct data products created from AMSR-E satellite passive microwave observations: GlobSnow snow water equivalent (SWE), and NTSG growing-season AMSR-E Land Parameters (air temperature, soil moisture and vegetation transmissivity). Due to the complex and interconnected nature of processes determining snow and growing-season land surface characteristics, these associations were analyzed using the modern nonparametric technique of alternating conditional expectations (ACE), as this approach does not impose a predefined analytic form. Findings indicate that regions with lower vegetation transmissivity (more biomass) at the start and end of the growing season tend to accumulate less snow at the start and end of the snow season, possibly due to interception and sublimation. Warmer air temperatures at the start and end of the growing season were associated with diminished snow accumulation at the start and end of the snow season. High latitude sites with warmer mean annual growing-season temperatures tended to accumulate more snow, probably due to the greater availability of water vapor for snow season precipitation at warmer locations. Regions with drier

  1. Quantification winter wheat LAI with HJ-1CCD image features over multiple growing seasons

    NASA Astrophysics Data System (ADS)

    Li, Xinchuan; Zhang, Youjing; Luo, Juhua; Jin, Xiuliang; Xu, Ying; Yang, Wenzhi

    2016-02-01

    Remote sensing images are widely used to map leaf area index (LAI) continuously over landscape. The objective of this study is to explore the ideal image features from Chinese HJ-1 A/B CCD images for estimating winter wheat LAI in Beijing. Image features were extracted from such images over four seasons of winter wheat growth, including five vegetation indices (VIs), principal components (PC), tasseled cap transformations (TCT) and texture parameters. The LAI was significantly correlated with the near-infrared reflectance band, five VIs [normalized difference vegetation index, enhanced vegetation index (EVI), modified nonlinear vegetation index (MNLI), optimization of soil-adjusted vegetation index, and ratio vegetation index], the first principal component (PC1) and the second TCT component (TCT2). However, these image features cannot significantly improve the estimation accuracy of winter wheat LAI in conjunction with eight texture measures. To determine the few ideal features with the best estimation accuracy, partial least squares regression (PLSR) and variable importance in projection (VIP) were applied to predict LAI values. Four remote sensing features (TCT2, PC1, MNLI and EVI) were chosen based on VIP values. The result of leave-one-out cross-validation demonstrated that the PLSR model based on these four features produced better result than the ten features' model, throughout the whole growing season. The results of this study suggest that selecting a few ideal image features is sufficient for LAI estimation.

  2. Growing Food for Space and Earth: NASA's Contributions to Vertical Agriculture

    NASA Technical Reports Server (NTRS)

    Wheeler, Raymond M.

    2015-01-01

    Beginning in the 1980s with NASA's Controlled Ecological Life Support System (CELSS) Program and later the 1990s and early 2000s with the Advanced Life Support Project, NASA conducted extensive testing with crops in controlled environment conditions. One series of tests conducted at Kennedy Space Center used a large chamber with vertically stacked shelves to support hydroponic growing trays, with a bank of electric lamps above each shelf. This is essentially the same approach that has become popular for use in so-called vertical agriculture systems, which attempts to optimize plant production in a fixed volume. Some of the findings and commonalities of NASA's work during this period and how it overlaps with current interests in vertical agriculture will be presented in the talk.

  3. The variation of the water deficit during the winter wheat growing season and its impact on crop yield in the North China Plain.

    PubMed

    Wu, Jianjun; Liu, Ming; Lü, Aifeng; He, Bin

    2014-11-01

    The North China Plain (NCP) is one of the main agricultural areas in China. However, it is also widely known for its water shortages, especially during the winter wheat growing season. Recently, climate change has significantly affected the water environment for crop growth. Analyzing the changes in the water deficit, which is only affected by climate factor, will help to improve water management in the NCP. In this study, the Decision Support System for Agrotechnology Transfer (DSSAT) was used to investigate the variations in the water deficit during the winter wheat growing season from 1961 to 2010 in 12 selected stations in the NCP. To represent the changes in the water deficit without any artificial affection, the rainfed simulation was used. Over the past 50 years, the average temperature during the winter wheat growing season increased approximately 1.42 °C. The anthesis date moved forward approximately 7-10 days and to late April, which increased the water demand in April. Precipitation in March and May showed a positive trend, but there was a negative trend in April. The water deficit in late April and early May became more serious than before, with an increasing trend of more than 0.1 mm/year. In addition, because the heading stage, which is very important to crop yield of winter wheat, moved forward, the impact of water deficit in late April was more serious to crop yield. PMID:24531705

  4. The variation of the water deficit during the winter wheat growing season and its impact on crop yield in the North China Plain

    NASA Astrophysics Data System (ADS)

    Wu, Jianjun; Liu, Ming; Lü, Aifeng; He, Bin

    2014-02-01

    The North China Plain (NCP) is one of the main agricultural areas in China. However, it is also widely known for its water shortages, especially during the winter wheat growing season. Recently, climate change has significantly affected the water environment for crop growth. Analyzing the changes in the water deficit, which is only affected by climate factor, will help to improve water management in the NCP. In this study, the Decision Support System for Agrotechnology Transfer (DSSAT) was used to investigate the variations in the water deficit during the winter wheat growing season from 1961 to 2010 in 12 selected stations in the NCP. To represent the changes in the water deficit without any artificial affection, the rainfed simulation was used. Over the past 50 years, the average temperature during the winter wheat growing season increased approximately 1.42 °C. The anthesis date moved forward approximately 7-10 days and to late April, which increased the water demand in April. Precipitation in March and May showed a positive trend, but there was a negative trend in April. The water deficit in late April and early May became more serious than before, with an increasing trend of more than 0.1 mm/year. In addition, because the heading stage, which is very important to crop yield of winter wheat, moved forward, the impact of water deficit in late April was more serious to crop yield.

  5. Mercury cycling in agricultural and managed wetlands, Yolo Bypass, California: Spatial and seasonal variations in water quality

    USGS Publications Warehouse

    Alpers, Charles N.; Fleck, Jacob A.; Marvin-DiPasquale, Mark C.; Stricker, Craig A.; Stephenson, Mark; Taylor, Howard E.

    2014-01-01

    The seasonal and spatial variability of water quality, including mercury species, was evaluated in agricultural and managed, non-agricultural wetlands in the Yolo Bypass Wildlife Area, an area managed for multiple beneficial uses including bird habitat and rice farming. The study was conducted during an 11-month period (June 2007 to April 2008) that included a summer growing season and flooded conditions during winter. Methylmercury (MeHg) concentrations in surface water varied over a wide range (0.1 to 37 ng L−1 unfiltered; 0.04 to 7.3 ng L−1 filtered). Maximum MeHg values are among the highest ever recorded in wetlands. Highest MeHg concentrations in unfiltered surface water were observed in drainage from wild rice fields during harvest (September 2007), and in white rice fields with decomposing rice straw during regional flooding (February 2008). The ratio of MeHg to total mercury (MeHg/THg) increased about 20-fold in both unfiltered and filtered water during the growing season (June to August 2007) in the white and wild rice fields, and about 5-fold in fallow fields (July to August 2007), while there was little to no change in MeHg/THg in the permanent wetland. Sulfate-bearing fertilizer had no effect on Hg(II) methylation, as sulfate-reducing bacteria were not sulfate limited in these agricultural wetlands. Concentrations of MeHg in filtered and unfiltered water correlated with filtered Fe, filtered Mn, DOC, and two indicators of sulfate reduction: the SO4 2 −/Cl− ratio, and δ34S in aqueous sulfate. These relationships suggest that microbial reduction of SO4 2−, Fe(III), and possibly Mn(IV) may contribute to net Hg(II)-methylation in this setting.

  6. Effects of urban green infrastructure (UGI) on local outdoor microclimate during the growing season.

    PubMed

    Wang, Yafei; Bakker, Frank; de Groot, Rudolf; Wörtche, Heinrich; Leemans, Rik

    2015-12-01

    This study analyzed how the variations of plant area index (PAI) and weather conditions alter the influence of urban green infrastructure (UGI) on microclimate. To observe how diverse UGIs affect the ambient microclimate through the seasons, microclimatic data were measured during the growing season at five sites in a local urban area in The Netherlands. Site A was located in an open space; sites B, C, and D were covered by different types and configurations of green infrastructure (grove, a single deciduous tree, and street trees, respectively); and site E was adjacent to buildings to study the effects of their façades on microclimate. Hemispherical photography and globe thermometers were used to quantify PAI and thermal comfort at both shaded and unshaded locations. The results showed that groves with high tree density (site B) have the strongest effect on microclimate conditions. Monthly variations in the differences of mean radiant temperature (∆Tmrt) between shaded and unshaded areas followed the same pattern as the PAI. Linear regression showed a significant positive correlation between PAI and ∆Tmrt. The difference of daily average air temperature (∆T a ) between shaded and unshaded areas was also positively correlated to PAI, but with a slope coefficient below the measurement accuracy (±0.5 °C). This study showed that weather conditions can significantly impact the effectiveness of UGI in regulating microclimate. The results of this study can support the development of appropriate UGI measures to enhance thermal comfort in urban areas. PMID:26547322

  7. Quantifying the growing season dynamics and phenology of a boreal black spruce wildfire chronosequence: Coupling field measurements with MODIS

    NASA Astrophysics Data System (ADS)

    Serbin, S. P.; Ahl, D. E.; Gower, S. T.

    2007-12-01

    The boreal forest is the second largest forested biome and the vast area and large carbon stores in the soil makes these forests important to the global carbon, water and energy cycles. Analysis of global coverage, coarse resolution satellite Vegetation Index (VI) data have provided considerable information on the seasonal cycles of vegetation in the mid-to high-latitudes, including the boreal forest, with evidence of an increase in the magnitude of vegetation greenness and a lengthening of the active growing season, which has been attributed to climate warming. However, boreal forests are prone to extensive wildfire disturbance that influence canopy dynamics (i.e. species composition, LAI, and phenology) and separating the direct affect of warming from the indirect affect of increased wildfire frequency on the patterns of boreal phenology and seasonal greeness requires further analysis coupled to ground measurements. In this research we address the need for detailed information on the growing season dynamics and phenological patterns of boreal vegetation. We evaluate whether MODIS reflectance data can resolve small inter-annual variations in canopy phenology and growing season dynamics of boreal forests. We quantified the seasonality and inter-annual differences of the overstory and understory vegetation by optically measuring the LAI and light harvesting potential (FPAR) during the 2004-2006 growing seasons. An automated continuously operating system is used to monitor growing season PAR transmittance. We focused on a boreal wildfire chronosequence of sites comprising a range of forest ages (1-154 years since fire) to quantify the differences in vegetation dynamics and phenology between the deciduous/mixed and coniferous forests. The spatial and temporal characteristics of LAI / FPAR within the chronosequence were examined by comparing both the in situ measurements and the relevant MODIS products. A statistical curve fitting procedure is used to derive the key

  8. Early and late seasonal carbon sequestration and allocation in larch trees growing on permafrost in Central Siberia

    NASA Astrophysics Data System (ADS)

    Masyagina, Oxana; Prokushkin, Anatoly; Kirdyanov, Alexander; Artyukhov, Aleksey; Udalova, Tatiana; Senchenkov, Sergey; Rublev, Aleksey

    2014-05-01

    Despite large geographic extent of deciduous conifer species Larix gmelinii, its seasonal photosynthetic activity and translocation of photoassimilated carbon within a tree remain poorly studied. To get better insight into productivity of larch trees growing on permafrost soils in Siberian larch biome we aimed to analyze dynamics of foliage parameters (i.e. leaf area, biomass, %N, %P etc.), seasonal dynamics of photosynthetic activity and apply whole tree labeling by 13CO2, which is powerful and effective tool for tracing newly developed assimilates translocation to tissues and organs of a tree (Kagawa et al., 2006; Keel et al., 2012). Experimental plot has been established in mature 105 year-old larch stand located within the continuous permafrost area near Tura settlement (Central Siberia, 64o17'13" N, 100o11'55" E, 148 m a.s.l.). Trees selected for experiments represented mean tree of the stand. Measurements of seasonal photosynthetic activity and foliar biomass sampling were arranged from early growing season (June 8, 2013) until yellowing and senescence of needles on September 17, 2013. Labeling by 13C in whole tree chamber was conducted by three pulses ([CO2]max ≤ 2,500 ppmv, 13CO2 (30% v/v)) at the early (June) and late (August) phase of growing season for different trees in 3 replicates each time. Both early season and late season labeling experiments demonstrated high rate of 13CO2 assimilation and respective enrichment of needle tissues by 13C: δ13C increased from -28.7 up to +670‰ just after labeling. However, there was distinct post-labeling dynamics of needle δ13C among two seasonal experiments. At the early season 13C depletion in labeled needles was slower, and δ13C approached after 40 days ca. +110 ‰ and remained constant till senescence. In the late season (August) needles were losing labeled C with much faster rate and approached only +1.5 ‰ upon senescence (28 days exposition). These findings suggest that in early season ca. 20% of

  9. 317/319 Phytoremediation site monitoring report - 2009 growing season : final report.

    SciTech Connect

    Negri, C .N.; Benda, P. L.; Gopalakrishnan, G.; Energy Systems

    2010-02-10

    In 1999, Argonne National Laboratory (Argonne) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems (ES) Division in the growing season of 2009. Monitoring of the planted trees began soon after the trees were installed in 1999 and has been conducted every summer since then. As the trees grew and consolidated their growth into the contaminated soil and groundwater, their exposure to the contaminants was progressively shown through tissue sampling. During the 2009 sampling campaign, VOC concentrations found in the French Drain area were in general consistent with or slightly lower than the 2008 results. Additionally, closely repeated, stand wide analyses showed contaminant fluctuations that may indicate short-term contaminant depletion in the area of interest of roots. This data will be useful to determine short-term removal rate by the trees. As in previous years, levels in the Hydraulic Control Area were close to background levels except for a few exceptions.

  10. Seasonality on the rainfall partitioning of a fast-growing tree plantation under Mediterranean conditions

    NASA Astrophysics Data System (ADS)

    molina, antonio; llorens, pilar; biel, carme

    2014-05-01

    Studies on rainfall interception in fast-growing tree plantations are less numerous than those in natural forests. Trees in these plantations are regularly distributed, and the canopy cover is clumped but changes quickly, resulting on high variability in the volume and composition of water that reach the soil. In addition, irrigation supply is normally required in semiarid areas to get optimal wood production; consequently, knowing rainfall interception and its yearly evolution is crucial to manage the irrigation scheme properly. This work studies the rainfall partitioning seasonality in a cherry tree (Prunus avium) plantation orientated to timber production under Mediterranean conditions. The monitoring design started on March 2012 and consists of a set of 58 throughfall tipping buckets randomly distributed (based on a 1x1 m2 grid) in a plot of 128 m2 with 8 trees. Stemflow is measured in all the trees with 2 tipping buckets and 6 accumulative collectors. Canopy cover is regularly measured throughout the study period, in leaf and leafless periods, by mean of sky-orientated photographs taken 50 cm above the center of each tipping bucket. Others tree biometrics are also measured such as diameter and leaf area index. Meteorological conditions are measured at 2 m above the forest cover. This work presents the first analyses describing the rainfall partitioning and its dependency on canopy cover, distance to tree and meteorological conditions. The modified Gash' model for rainfall interception in dispersed vegetation is also preliminary evaluated.

  11. Simulated water fluxes during the growing season in semiarid grassland ecosystems under severe drought conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Na; Liu, Chengyu

    2014-05-01

    To help improve understanding of how changes in climate and land cover affect water fluxes, water budgets, and the structure and function of regional grassland ecosystems, the Grassland Landscape Productivity Model (GLPM) was used to simulate spatiotemporal variation in primary water fluxes. The study area was a semiarid region in Inner Mongolia, China, in 2002, when severe drought was experienced. For Stipa grandis steppe, Leymus chinensis steppe, shrubland, and croplands, the modeled total, daily and monthly averaged, and maximum evapotranspiration during the growing season and the modeled water deficits were similar to those measured in Inner Mongolia under similar precipitation conditions. The modeled temporal variations in daily evaporation rate, transpiration rate, and evapotranspiration rate for the typical steppes also agreed reasonably well with measured trends. The results demonstrate that water fluxes varied in response to spatiotemporal variations in environmental factors and associated changes in the phenological and physiological characteristics of plants. It was also found that transpiration and evapotranspiration (rather than precipitation) were the primary factors controlling differences in water deficit among land cover types. The results also demonstrate that specific phenomena occur under severe drought conditions; these phenomena are considerably different to those occurring under normal or well-watered conditions. The findings of the present study will be useful for evaluating day-scale water fluxes and their relationships with climate change, hydrology, land cover, and vegetation dynamics.

  12. Long-term experimentally deepened snow decreases growing-season respiration in a low- and high-arctic tundra ecosystem

    NASA Astrophysics Data System (ADS)

    Semenchuk, Philipp R.; Christiansen, Casper T.; Grogan, Paul; Elberling, Bo; Cooper, Elisabeth J.

    2016-05-01

    Tundra soils store large amounts of carbon (C) that could be released through enhanced ecosystem respiration (ER) as the arctic warms. Over time, this may change the quantity and quality of available soil C pools, which in-turn may feedback and regulate ER responses to climate warming. Therefore, short-term increases in ER rates due to experimental warming may not be sustained over longer periods, as observed in other studies. One important aspect, which is often overlooked, is how climatic changes affecting ER in one season may carry-over and determine ER in following seasons. Using snow fences, we increased snow depth and thereby winter soil temperatures in a high-arctic site in Svalbard (78°N) and a low-arctic site in the Northwest Territories, Canada (64°N), for 5 and 9 years, respectively. Deepened snow enhanced winter ER while having negligible effect on growing-season soil temperatures and soil moisture. Growing-season ER at the high-arctic site was not affected by the snow treatment after 2 years. However, surprisingly, the deepened snow treatments significantly reduced growing-season ER rates after 5 years at the high-arctic site and after 8-9 years at the low-arctic site. We speculate that the reduction in ER rates, that became apparent only after several years of experimental manipulation, may, at least in part, be due to prolonged depletion of labile C substrate as a result of warmer soils over multiple cold seasons. Long-term changes in winter climate may therefore significantly influence annual net C balance not just because of increased wintertime C loss but also because of "legacy" effects on ER rates during the following growing seasons.

  13. Early Season Goose Grazing Has a Greater Effect Than Advancement of the Growing Season on Net Ecosystem Exchange in a Sub-Arctic Coastal Wetland of Western Alaska

    NASA Astrophysics Data System (ADS)

    Leffler, A. J.; Choi, R. T.; Beard, K. H.; Schmutz, J. A.; Welker, J. M.

    2014-12-01

    The wetlands of the Yukon-Kuskokwim Delta in western Alaska are important breeding areas for geese and are experiencing rapid climate change. Growing seasons now begin earlier but geese have not advanced their breeding enough to match the advancement of spring. Consequently, geese enter a greener system that may be less nutritious than in the past because grasses and sedges have highest nutrient density shortly following emergence. One consequence of this changing phenology is that vegetation consumed by geese and returned as feces may have a different carbon to nitrogen ratio than in the past, which may influence net ecosystem exchange (NEE). We examine the effect of the advancement of the growing season and different arrival times by Brant Geese on NEE. Our study consists of six experimental blocks, each with nine plots. Half of the plots are warmed to advance the growing season. Two plots each receive early, mid, and late season grazing; the remaining two plots are not grazed and there is one control plot. In one block, we monitor NEE hourly with an automatic gas exchange system. In the other blocks, survey measurements of NEE and ecosystem respiration (ER) are made periodically with a portable system. Geese remove considerable vegetation from the system and maintain "grazing lawns" <1 cm tall of high quality forage. Plots grazed in the early summer were net sources of C to the atmosphere, releasing ca. 2-4 g m-2 d-1. Non-grazed plots were C sinks of similar magnitude. Grazing had little effect on ER but an advanced growing season enhanced ER in the plots by ca. 0.5 μmol m-2 s-1. We observed a similar advanced growing season effect on NEE that we attribute to enhanced ER. Consequently, the larger influence on NEE in the system is grazing and this influence is through removal of photosynthetic tissue. Grazing by Brant Geese shifts large areas of this coastal wetland to a C source while advanced growing season only reduces the strength of the C sink.

  14. Mercury cycling in agricultural and managed wetlands of California: seasonal influences of vegetation on mercury methylation, storage, and transport

    USGS Publications Warehouse

    Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark C.; Kakouros, Evangelos; Agee, Jennifer L.; Kieu, Le H.; Stricker, Craig A.; Fleck, Jacob A.; Ackerman, Joshua T.

    2013-01-01

    Plants are a dominant biologic and physical component of many wetland capable of influencing the internal pools and fluxes of methylmercury (MeHg). To investigate their role with respect to the latter, we examined the changing seasonal roles of vegetation biomass and Hg, C and N composition from May 2007-February 2008 in 3 types of agricultural wetlands (domesticated or white rice, wild rice, and fallow fields), and in adjacent managed natural wetlands dominated by cattail and bulrush (tule). We also determined the impact of vegetation on seasonal microbial Hg methylation rates, and Hg and MeHg export via seasonal storage in vegetation, and biotic consumption of rice seed. Despite a compressed growing season of ~ 3 months, annual net primary productivity (NPP) was greatest in white rice fields and carbon more labile (leaf median C:N ratio = 27). Decay of senescent litter (residue) was correlated with microbial MeHg production in winter among all wetlands. As agricultural biomass accumulated from July to August, THg concentrations declined in leaves but MeHg concentrations remained consistent, such that MeHg pools generally increased with growth. Vegetation provided a small, temporary, but significant storage term for MeHg in agricultural fields when compared with hydrologic export. White rice and wild rice seeds reached mean MeHg concentrations of 4.1 and 6.2 ng gdw- 1, respectively. In white rice and wild rice fields, seed MeHg concentrations were correlated with root MeHg concentrations (r = 0.90, p < 0.001), suggesting transport of MeHg to seeds from belowground tissues. Given the proportionally elevated concentrations of MeHg in rice seeds, white and wild rice crops may act as a conduit of MeHg into biota, especially waterfowl which forage heavily on rice seeds within the Central Valley of California, USA. Thus, while plant tissues and rhizosphere soils provide temporary storage for MeHg during the growing season, export of MeHg is enhanced post-harvest through

  15. Seasonal and cumulative loblolly pine development under two stand density and fertility levels through four growing seasons. Forest Service research paper

    SciTech Connect

    Haywood, J.D.

    1994-06-01

    A loblolly pine (Pinus taeda) plantation was subjected to two cultural treatments to examine seasonal cumulative pine development in the 9th through 12th growing seasons: (1) pine stocking was either reduced by thinning to 303 trees per acre at a 12- by 12-ft spacing or the plots were left uncut with an original density of 1,210 trees per acre at a 6- by 6-ft spacing, and (2) either no fertilizer was applied or diammonium phosphate was broadcast at 134 lb of phosphorus and 120 lb of nitrogen per acre. Competing vegetation was controlled on all plots. Thinning resulted in less spring height growth in the 9th and 10th growing seasons that not cutting, but thinning increased diameter growth each year. Beginning in the 10th growing season, fertilization increased height, diameter, and basal area per acre growth, with the effect of fertilization on diameter growth being most pronounced on the thinned plots. Therefore, fertilization of thinned plots was more beneficial than thinning alone, and thinning alone resulted in less height and basal area per acre growth than the other treatment combinations for the 4-year period.

  16. Non-growing season soil CO2 efflux patterns in five land-use types in northern China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Overgrazing and unsuitable farming practices have led to grassland degradation in northern China. This studhy examined soil CO2 efflux (Fc) from five land-use types during the non-growing season on the southeastern edge of the Mongolian Plateau in China. The land-use types included three native v...

  17. n-Alkane biosynthetic hydrogen isotope fractionation is not constant throughout the growing season in the riparian tree Salix viminalis

    NASA Astrophysics Data System (ADS)

    Newberry, Sarah L.; Kahmen, Ansgar; Dennis, Paul; Grant, Alastair

    2015-09-01

    Compound-specific δ2H values of leaf wax n-alkanes have emerged as a potentially powerful paleohydrological proxy. Research suggests terrestrial plant n-alkane δ2H values are strongly correlated with meteoric water δ2H values, and may provide information on temperature, relative humidity, evaporation, and precipitation. This is based upon several assumptions, including that biosynthetic fractionation of n-alkanes during synthesis is constant within a single species. Here we present a multi-isotope study of the n-alkanes of riparian Salix viminalis growing in Norwich, UK. We measured n-alkane δ2H, leaf water δ2H, xylem water δ2H, and bulk foliar δ13C and evaluated the variability of n-alkane δ2H values and net biosynthetic fractionation (εlw-wax) over a whole growing season. S. viminalis n-alkane δ2H values decreased by 40‰ between the start of the growing season in April and the time when they stabilized in July. Variation in leaf and xylem water δ2H did not explain this variability. εlw-wax varied from -116‰ during leaf expansion in April to -156‰ during the stable phase. This suggests that differential biosynthetic fractionation was responsible for the strong seasonal trends in S. viminalis n-alkane δ2H values. We suggest that variability in εlw-wax is driven by seasonal differences in the carbohydrate source and thus the NADPH used in n-alkane biosynthesis, with stored carbohydrates utilized during spring and recent occurring growing season assimilates used later in the season. This is further supported by bulk foliar δ13C values, which are 13C-enriched during the period of leaf flush, relative to the end of the growing season. Our results challenge the assumption that biosynthetic fractionation is constant for a given species, and suggest that 2H-enriched stored assimilates are an important source for n-alkane biosynthesis early in the growing season. These findings have implications for the interpretation of sedimentary n-alkanes and call

  18. Earlier growing seasons and changes in migration timing influence carbon uptake and plant production in Arctic coastal wetlands

    NASA Astrophysics Data System (ADS)

    Leffler, A. J.; Beard, K. H.; Kelsey, K.; Choi, R. T.; Welker, J. M.

    2015-12-01

    The wetlands of the Yukon-Kuskokwim Delta in western Alaska are important breeding areas for geese and are experiencing rapid climate change, specifically earlier onset of the growing season. Consequently, geese arrive 'later' in the growing season than in the past, potentially setting up a phenological mismatch with consequences for their nutrition, plant growth, and C and N processes in the ecosystem. We examined the interactive effects between the start of the growing season and Black Brant arrival time on these processes in a manipulative experiment. Advancing the growing season had a modest influence on CO2 exchange and plant growth. An early growing season shifted the rate of net ecosystem exchange (NEE) by 1-1.5 µmol m-2 s-1 toward a carbon (C) source. This change was driven by an increase in the rate of ecosystem respiration (ER). The advanced growing season nearly doubled the rate of leaf elongation in the early summer and this difference persisted as taller vegetation later in the year; belowground biomass was not affected. Timing of grazing had greater influence on CO2 exchange and plant growth. Grazing early in the season shifted the system to a carbon source by ca. 2 μmol m-2 s-1 while delaying grazing enhanced the carbon sink by 1 μmol m-2 s-1. Here, the influence was not through ER, but through reducing and enhancing standing leaf area, respectively. Early grazing also reduced season-long root production by over 50% while delayed grazing enhanced root production by 30%. Although delaying grazing enhanced C uptake and promoted plant growth in this ecosystem, leaf tissue in delayed-grazing plots had C:N of 16.7 compared to 14.2 in the typical-grazing plots, potentially reducing the digestibility of goose forage and slowing rates of decomposition. Biotic forcing in arctic tundra can thus be major drivers of ecosystem function and need to be considered as tundra system respond to changing conditions.

  19. SEASONAL VARIATIONS OF NITRIC OXIDE FLUX FROM AGRICULTURAL SOILS IN THE SOUTHEAST UNITED STATES

    EPA Science Inventory

    Fluxes of nitric oxide (NO) were measured from the summer of 1994 to the spring of 1995 from an intensively managed agricultural soil using a dynamic flow through chamber technique in order to study the seasonal variability in the emissions of NO. The measurements were made on a ...

  20. HEALTH CONDITIONS AND SERVICES FOR DOMESTIC SEASONAL AGRICULTURAL WORKERS AND THEIR FAMILIES IN CALIFORNIA.

    ERIC Educational Resources Information Center

    California State Dept. of Public Health, Berkeley.

    FIELD INTERVIEWS WERE HELD WITH COMMUNITY LEADERS AND WITH SEVERAL HUNDRED WORKERS' FAMILIES. THE ACQUIRED INFORMATION SUPPLEMENTED A SURVEY OF PAST AND PRESENT CONDITIONS AND ASSISTED IN FORMULATING RECOMMENDATIONS FOR ACTION TO MEET THE ACUTE HEALTH NEEDS OF CALIFORNIA'S SEASONAL AGRICULTURAL WORKERS. THE HEALTH PROBLEM CAN BE MET BY LOCAL…

  1. Toward the resolution of microscopic seasonal variations in slow growing speleothems by ELA-ICP-MS

    NASA Astrophysics Data System (ADS)

    Miller, N. R.; Wong, C. I.; Cunningham, M. T.; Banner, J. L.

    2011-12-01

    Speleothems constitute potential seasonal proxies of terrestrial environmental change over multi-decadal to millennial time-scales, but have highly variable growth rates that bear on the practical spatial resolution that is achievable by conventional analytical approaches. Although attractive as possible chronometers of long-term environmental change, slow growing speleothems pose particular challenges for representative sampling required to obtain robust high-resolution geochemical time series. U-series dates demonstrate that many central Texas speleothems are slow growing records, with growth rates commonly in the range of 5-30 μm/yr. In contrast to fast-growth speleothems (i.e. >0.5 mm/yr), banding at predicted seasonal stratigraphic frequencies is not apparent by petrographic inspection. Complementary UV imagery reveals that band thicknesses can vary over short distances by a factor of 40, consistent with the allowable range of U-series growth rate estimates, but also suggesting that significant short-term growth rate variations are possible, if not endemic, to such records. Excimer laser ablation, ELA-ICP-MS, offers potential solutions to the sampling challenges posed by finely banded speleothems, but signal to noise level at this small scale has not been widely explored. We present results of tests to improve fine-scale spatial resolution through optimization of conventional instrumental variables associated with measurement and hardware changes. The latter include adoption of rectangular slit apertures, a large-format laser cell with localized "fast" sampling of the ablation plume, and a high energy optical attenuator. We focus on two speleothems from the same locality, having median U-series growth rates of ~15 μm/year, and employ slow line scans using a narrow slit aperture. Our approach is to modulate instrumental parameters (laser power, rep rate, scan rate, He flow) to obtain symmetrical wash-in and wash-out times, while obtaining lowest possible RSDs

  2. Sensitivity study of reference crop evapotranspiration during growing season in the West Liao River basin, China

    NASA Astrophysics Data System (ADS)

    Gao, Zhendong; He, Junshi; Dong, Kebao; Bian, Xiaodong; Li, Xiang

    2016-05-01

    We have analyzed the trends of reference crop evapotranspiration (ET0) through the Penman-Monteith model and climate factors in the West Liao River basin using the Mann-Kendall test after removing the effect of significant lag-1 serial correlation from the time series of the data by trend-free pre-whitening. The changing characteristics of the sensitivity coefficients and the spatial distribution during growing season are investigated, and the correlation between the sensitivity coefficients with elevation and the key climate factors by relative contribution and stepwise regression methods are evaluated. A significant overall increase in air temperature, and a significant decrease in wind speed, solar radiation, sunshine duration, relative humidity, and a slight decrease in ET0 are observed. Sensitivity analysis shows that ET0 is most sensitive to solar radiation, followed by relative humidity. In contrast, ET0 is least sensitive to the average air temperature. The sensitivity coefficients for the maximum and minimum air temperature and relative humidity have a significant negative correlation with elevation, while the coefficients for other variables are not strongly correlated with elevation. The spatial distribution of the sensitivity coefficients for wind speed and solar radiation is opposite, i.e., in regions where the sensitivity coefficients for wind speed are high; the sensitivity coefficients for solar radiation are low and vice versa. The sensitivity for relative humidity and average air temperature is region specific in the plain area. However, ET0 is most sensitive to the climate change in regions of high elevation. Wind speed is the most dominant contributor followed by solar radiation. Average air temperature contributes the least. The stepwise regression analysis indicates that wind speed is the foremost dominant variable influencing ET0. Relative contribution and stepwise regression analysis can be used to determine the main variables affecting ET0

  3. Nutrient runoff from a Korean rice paddy watershed during multiple storm events in the growing season

    NASA Astrophysics Data System (ADS)

    Kim, Jin S.; Oh, Seung Y.; Oh, Kwang Y.

    2006-07-01

    SummaryThe concentrations and loading characteristics of total nitrogen (TN) and total phosphorous (TP) in runoff from a 50.1-ha rice paddy field watershed in South Korea were investigated for eight storm events during the 1998-2001 growing seasons. TN concentrations in total runoff were inversely related to discharge, except in periods with high fertilization rates. In contrast, TP concentrations were strongly proportional to discharge under non-ponded paddy conditions, but not correlated with discharge under most ponded paddy conditions. Stormflow and irrigation return flow were separated from total runoff using the constant-discharge method. The flow-weighted mean TN concentration in stormflow was lower than that in irrigation return flow, mainly because of rainwater dilution, except for periods with a residual fertilizer effect. The flow-weighted mean TP concentration in stormflow, however, was always higher than that in irrigation return flow, likely a result of sediment-associated phosphorus transport. The ratio of mean TP concentration in stormflow to that in irrigation return flow under ponded paddy conditions (1.6) was approximately one-half that under non-ponded conditions (3.1), suggesting that ponding on paddy fields played an important role in reducing soil erosion-related phosphorus export. Relationships between TN loads and stormflow runoff volumes were found except during a storm event in the high fertilization period ( p < 0.05). TP loads were also correlated with stormflow runoff volumes ( p < 0.05), except for storm events under non-ponded and dry antecedent conditions. These results indicate that nitrogen runoff from paddy field watersheds depends on fertilization rates, while phosphorus runoff is controlled by ponding conditions.

  4. Effects of application of corn straw on soil microbial community structure during the maize growing season.

    PubMed

    Lu, Ping; Lin, Yin-Hua; Yang, Zhong-Qi; Xu, Yan-Peng; Tan, Fei; Jia, Xu-Dong; Wang, Miao; Xu, De-Rong; Wang, Xi-Zhuo

    2015-01-01

    This study investigated the influence of corn straw application on soil microbial communities and the relationship between such communities and soil properties in black soil. The crop used in this study was maize (Zea mays L.). The five treatments consisted of applying a gradient (50, 100, 150, and 200%) of shattered corn straw residue to the soil. Soil samples were taken from May through September during the 2012 maize growing season. The microbial community structure was determined using phospholipid fatty acid (PLFA) analysis. Our results revealed that the application of corn straw influenced the soil properties and increased the soil organic carbon and total nitrogen. Applying corn straw to fields also influenced the variation in soil microbial biomass and community composition, which is consistent with the variations found in soil total nitrogen (TN) and soil respiration (SR). However, the soil carbon-to-nitrogen ratio had no effect on soil microbial communities. The abundance of PLFAs, TN, and SR was higher in C1.5 than those in other treatments, suggesting that the soil properties and soil microbial community composition were affected positively by the application of corn straw to black soil. A Principal Component Analysis indicated that soil microbial communities were different in the straw decomposition processes. Moreover, the soil microbial communities from C1.5 were significantly different from those of CK (p < 0.05). We also found a high ratio of fungal-to-bacterial PLFAs in black soil and significant variations in the ratio of monounsaturated-to-branched fatty acids with different straw treatments that correlated with SR (p < 0.05). These results indicated that the application of corn straw positively influences soil properties and soil microbial communities and that these properties affect these communities. The individual PLFA signatures were sensitive indicators that reflected the changes in the soil environment condition. PMID:24652702

  5. Crop evapotranspiration-based irrigation management during the growing season in the arid region of northwestern China.

    PubMed

    Chang, Xuexiang; Zhao, Wenzhi; Zeng, Fanjiang

    2015-11-01

    In arid northwestern China, water shortages have triggered recent regulations affecting irrigation water use in desert-oasis agricultural systems. In order to determine the actual water demand of various crops and to develop standards for the rational use of water resources, we analyzed meteorological data from the Fukang desert ecosystem observation and experiment station (FKD), the Cele desert-grassland ecosystem observation and research station (CLD), and the Linze Inland River Basin Comprehensive Research Station (LZD), which all belong to the Chinese Ecosystem Research Network. We researched crop evapotranspiration (ETc) using the water balance method, the FAO-56 Penman-Monteith method, the Priestley-Taylor method, and the Hargreaves method, during the growing seasons of 2005 through 2009. Results indicate substantial differences in ETc, depending on the method used. At the CLD, the ETc from the soil water balance, FAO-56 Penman-Monteith, Priestley-Taylor, and Hargreaves methods were 1150.3±380.8, 783.7±33.6, 1018.3±22.1, and 611.2±23.3 mm, respectively; at the FKD, the corresponding results were 861.0±67.0, 834.2±83.9, 1453.5±47.1, and 1061.0±38.2 mm, respectively; and at the LZD, 823.4±110.4, 726.0±0.4, 722.3±29.4, and 1208.6±79.1 mm, respectively. The FAO-56 Penman-Monteith method provided a fairly good estimation of E Tc compared with the Priestley-Taylor and Hargreaves methods. PMID:26497559

  6. Growing season temperature and precipitation variability and extremes in the U.S. Corn Belt from 1981 to 2012

    NASA Astrophysics Data System (ADS)

    Dai, S.; Shulski, M.

    2013-12-01

    Climate warming and changes in rainfall patterns and increases in extreme events are resulting in higher risks of crop failures. A greater sense of urgency has been induced to understand the impacts of past climate on crop production in the U.S. As one of the most predominant sources of feed grains, corn is also the main source of U.S. ethanol. In the U.S. Corn Belt, region-scale evaluation on temperature and precipitation variability and extremes during the growing season is not well-documented yet. This study is part of the USDA-funded project 'Useful to Usable: Transforming climate variability and change information for cereal crop producers'. The overall goal of our work is to study the characteristics of average growing season conditions and changes in growing season temperature- and precipitation-based indices that are closely correlated with corn grain yield in the U.S. Corn Belt. The research area is the twelve major Corn Belt states, including IL, IN, IA, KS, MI, MN, MO, NE, OH, SD, ND, and WI. Climate data during 1981-2010 from 132 meteorological stations (elevation ranges from 122 m to 1,202 m) are used in this study, including daily minimum, maximum, and mean temperature, and daily precipitation. From 1981 to 2012, beginning date (BD), ending date (ED), and growing season length (GSL) in the climatological corn growing season are studied. Especially, during the agronomic corn growing season, from Apr to Oct, temperature- and precipitation-based indices are analyzed. The temperature-based indices include: number of days with daily mean temperature below 10°C, number of days with daily mean temperature above 30°C, the sum of growing degree days (GDD) between 10°C to 30°C (GDD10,30, growth range for corn), the sum of growing degree days above 30°C (GDD30+, exposure to harmful warming for corn), the sum of growing degree days between 0°C and 44°C (GDD0,44, survival range limits for corn), the sum of growing degree days between 5°C and 35°C (GDD5

  7. Diurnal patterns of gas-exchange and metabolic pools in tundra plants during three phases of the arctic growing season

    PubMed Central

    Patankar, Rajit; Mortazavi, Behzad; Oberbauer, Steven F; Starr, Gregory

    2013-01-01

    Arctic tundra plant communities are subject to a short growing season that is the primary period in which carbon is sequestered for growth and survival. This period is often characterized by 24-h photoperiods for several months a year. To compensate for the short growing season tundra plants may extend their carbon uptake capacity on a diurnal basis, but whether this is true remains unknown. Here, we examined in situ diurnal patterns of physiological activity and foliar metabolites during the early, mid, and late growing season in seven arctic species under light-saturated conditions. We found clear diurnal patterns in photosynthesis and respiration, with midday peaks and midnight lulls indicative of circadian regulation. Diurnal patterns in foliar metabolite concentrations were less distinct between the species and across seasons, suggesting that metabolic pools are likely governed by proximate external factors. This understanding of diurnal physiology will also enhance the parameterization of process-based models, which will aid in better predicting future carbon dynamics for the tundra. This becomes even more critical considering the rapid changes that are occurring circumpolarly that are altering plant community structure, function, and ultimately regional and global carbon budgets. PMID:23467719

  8. Temporal disparity in leaf chlorophyll content and leaf area index across a growing season in a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Croft, H.; Chen, J. M.; Zhang, Y.

    2014-12-01

    Spatial and temporal variations in canopy structure and leaf biochemistry have considerable influence on fluxes of CO2, water and energy and nutrient cycling in vegetation. Two vegetation indices (VI), NDVI and Macc01, were used to model the spatio-temporal variability of broadleaf chlorophyll content and leaf area index (LAI) across a growing season. Ground data including LAI, hyperspectral leaf reflectance factors (400-2500 nm) and leaf chlorophyll content were measured across the growing season and satellite-derived canopy reflectance data was acquired for 33 dates at 1200 m spatial resolution. Key phenological information was extracted using the TIMESAT software. Results showed that LAI and chlorophyll start of season (SOS) dates were at day of year (DOY) 130 and 157 respectively, and total season duration varied by 57 days. The spatial variability of chlorophyll and LAI phenology was also analyzed at the landscape scale to investigate phenological patterns over a larger spatial extent. Whilst a degree of spatial variability existed, results showed that chlorophyll SOS lagged approximately 20-35 days behind LAI SOS, and the end of season (EOS) LAI dates were predominantly between 20 and 30 days later than chlorophyll EOS. The large temporal differences between VI-derived chlorophyll content and LAI has important implications for biogeochemical models using NDVI or LAI to represent the fraction of photosynthetically active radiation absorbed by a canopy, in neglecting to account for delays in chlorophyll production and thus photosynthetic capacity.

  9. Strong contribution of autumn phenology to changes in satellite-derived growing season length estimates across Europe (1982-2011).

    PubMed

    Garonna, Irene; de Jong, Rogier; de Wit, Allard J W; Mücher, Caspar A; Schmid, Bernhard; Schaepman, Michael E

    2014-11-01

    Land Surface Phenology (LSP) is the most direct representation of intra-annual dynamics of vegetated land surfaces as observed from satellite imagery. LSP plays a key role in characterizing land-surface fluxes, and is central to accurately parameterizing terrestrial biosphere-atmosphere interactions, as well as climate models. In this article, we present an evaluation of Pan-European LSP and its changes over the past 30 years, using the longest continuous record of Normalized Difference Vegetation Index (NDVI) available to date in combination with a landscape-based aggregation scheme. We used indicators of Start-Of-Season, End-Of-Season and Growing Season Length (SOS, EOS and GSL, respectively) for the period 1982-2011 to test for temporal trends in activity of terrestrial vegetation and their spatial distribution. We aggregated pixels into ecologically representative spatial units using the European Landscape Classification (LANMAP) and assessed the relative contribution of spring and autumn phenology. GSL increased significantly by 18-24 days decade(-1) over 18-30% of the land area of Europe, depending on methodology. This trend varied extensively within and between climatic zones and landscape classes. The areas of greatest growing-season lengthening were the Continental and Boreal zones, with hotspots concentrated in southern Fennoscandia, Western Russia and pockets of continental Europe. For the Atlantic and Steppic zones, we found an average shortening of the growing season with hotspots in Western France, the Po valley, and around the Caspian Sea. In many zones, changes in the NDVI-derived end-of-season contributed more to the GSL trend than changes in spring green-up, resulting in asymmetric trends. This underlines the importance of investigating senescence and its underlying processes more closely as a driver of LSP and global change. PMID:24797086

  10. Application of Medium and Seasonal Flood Forecasts for Agriculture Damage Assessment

    NASA Astrophysics Data System (ADS)

    Fakhruddin, Shamsul; Ballio, Francesco; Menoni, Scira

    2015-04-01

    Early warning is a key element for disaster risk reduction. In recent decades, major advancements have been made in medium range and seasonal flood forecasting. This progress provides a great opportunity to reduce agriculture damage and improve advisories for early action and planning for flood hazards. This approach can facilitate proactive rather than reactive management of the adverse consequences of floods. In the agricultural sector, for instance, farmers can take a diversity of options such as changing cropping patterns, applying fertilizer, irrigating and changing planting timing. An experimental medium range (1-10 day) and seasonal (20-25 days) flood forecasting model has been developed for Thailand and Bangladesh. It provides 51 sets of discharge ensemble forecasts of 1-10 days with significant persistence and high certainty and qualitative outlooks for 20-25 days. This type of forecast could assist farmers and other stakeholders for differential preparedness activities. These ensembles probabilistic flood forecasts have been customized based on user-needs for community-level application focused on agriculture system. The vulnerabilities of agriculture system were calculated based on exposure, sensitivity and adaptive capacity. Indicators for risk and vulnerability assessment were conducted through community consultations. The forecast lead time requirement, user-needs, impacts and management options for crops were identified through focus group discussions, informal interviews and community surveys. This paper illustrates potential applications of such ensembles for probabilistic medium range and seasonal flood forecasts in a way that is not commonly practiced globally today.

  11. Geospatial approach for assessment of biophysical vulnerability to agricultural drought and its intra-seasonal variations.

    PubMed

    Sehgal, Vinay Kumar; Dhakar, Rajkumar

    2016-03-01

    The study presents a methodology to assess and map agricultural drought vulnerability during main kharif crop season at local scale and compare its intra-seasonal variations. A conceptual model of vulnerability based on variables of exposure, sensitivity, and adaptive capacity was adopted, and spatial datasets of key biophysical factors contributing to vulnerability were generated using remote sensing and GIS for Rajasthan State of India. Hazard exposure was based on frequency and intensity of gridded standardized precipitation index (SPI). Agricultural sensitivity was based on soil water holding capacity as well as on frequency and intensity of normalized difference vegetation index (NDVI)-derived trend adjusted vegetation condition index (VCITadj). Percent irrigated area was used as a measure of adaptive capacity. Agricultural drought vulnerability was derived separately for early, mid, late, and whole kharif seasons by composting rating of factors using linear weighting scheme and pairwise comparison of multi-criteria evaluation. The regions showing very low to extreme rating of hazard exposure, drought sensitivity, and agricultural vulnerability were identified at all four time scales. The results indicate that high to extreme vulnerability occurs in more than 50% of net sown area in the state and such areas mostly occur in western, central, and southern parts. The higher vulnerability is on account of non-irrigated croplands, moderate to low water holding capacity of sandy soils, resulting in higher sensitivity, and located in regions with high probability of rainfall deficiency. The mid and late season vulnerability has been found to be much higher than that during early and whole season. Significant correlation of vulnerability rating with food grain productivity, drought recurrence period, crop area damaged in year 2009 and socioeconomic indicator of human development index (HDI) proves the general soundness of methodology. Replication of this methodology

  12. The Growing Season, but Not the Farming System, Is a Food Safety Risk Determinant for Leafy Greens in the Mid-Atlantic Region of the United States

    PubMed Central

    Marine, Sasha C.; Pagadala, Sivaranjani; Wang, Fei; Pahl, Donna M.; Melendez, Meredith V.; Kline, Wesley L.; Oni, Ruth A.; Walsh, Christopher S.; Everts, Kathryne L.; Buchanan, Robert L.

    2015-01-01

    Small- and medium-size farms in the mid-Atlantic region of the United States use varied agricultural practices to produce leafy greens during spring and fall, but the impact of preharvest practices on food safety risk remains unclear. To assess farm-level risk factors, bacterial indicators, Salmonella enterica, and Shiga toxin-producing Escherichia coli (STEC) from 32 organic and conventional farms were analyzed. A total of 577 leafy greens, irrigation water, compost, field soil, and pond sediment samples were collected. Salmonella was recovered from 2.2% of leafy greens (n = 369) and 7.7% of sediment (n = 13) samples. There was an association between Salmonella recovery and growing season (fall versus spring) (P = 0.006) but not farming system (organic or conventional) (P = 0.920) or region (P = 0.991). No STEC was isolated. In all, 10% of samples were positive for E. coli: 6% of leafy greens, 18% of irrigation water, 10% of soil, 38% of sediment, and 27% of compost samples. Farming system was not a significant factor for levels of E. coli or aerobic mesophiles on leafy greens but was a significant factor for total coliforms (TC) (P < 0.001), with higher counts from organic farm samples. Growing season was a factor for aerobic mesophiles on leafy greens (P = 0.004), with higher levels in fall than in spring. Water source was a factor for all indicator bacteria (P < 0.001), and end-of-line groundwater had marginally higher TC counts than source samples (P = 0.059). Overall, the data suggest that seasonal events, weather conditions, and proximity of compost piles might be important factors contributing to microbial contamination on farms growing leafy greens. PMID:25616798

  13. A Multiple-player-game Approach to Agricultural Water Use in Regions of Seasonal Drought

    NASA Astrophysics Data System (ADS)

    Lu, Z.

    2013-12-01

    In the wide distributed regions of seasonal drought, conflicts of water allocation between multiple stakeholders (which means water consumers and policy makers) are frequent and severe problems. These conflicts become extremely serious in the dry seasons, and are ultimately caused by an intensive disparity between the lack of natural resource and the great demand of social development. Meanwhile, these stakeholders are often both competitors and cooperators in water saving problems, because water is a type of public resource. Conflicts often occur due to lack of appropriate water allocation scheme. Among the many uses of water, the need of agricultural irrigation water is highly elastic, but this factor has not yet been made full use to free up water from agriculture use. The primary goal of this work is to design an optimal distribution scheme of water resource for dry seasons to maximize benefits from precious water resources, considering the high elasticity of agriculture water demand due to the dynamic of soil moisture affected by the uncertainty of precipitation and other factors like canopy interception. A dynamic programming model will be used to figure out an appropriate allocation of water resources among agricultural irrigation and other purposes like drinking water, industry, and hydropower, etc. In this dynamic programming model, we analytically quantify the dynamic of soil moisture in the agricultural fields by describing the interception with marked Poisson process and describing the rainfall depth with exponential distribution. Then, we figure out a water-saving irrigation scheme, which regulates the timetable and volumes of water in irrigation, in order to minimize irrigation water requirement under the premise of necessary crop yield (as a constraint condition). And then, in turn, we provide a scheme of water resource distribution/allocation among agriculture and other purposes, taking aim at maximizing benefits from precious water resources, or in

  14. Physiological responses of birch (Betula pendula) to ozone: a comparison between open-soil-grown trees exposed for six growing seasons and potted seedlings exposed for one season.

    PubMed

    Oksanen, Elina

    2003-06-01

    Physiological responses of 4-year-old potted saplings of an O3-tolerant clone of Betula pendula Roth to short-term ozone (O3) exposure (one growing season) were compared with those of 6-year-old open-soil-grown trees of the same clone fumigated with O3 for six growing seasons. In the 2001 growing season, both groups of plants were exposed to ambient (control) and 1.6x ambient (elevated) O3 concentration under similar microclimatic conditions in a free air O3 exposure facility. Growth, net photosynthesis, stomatal conductance, stomatal density, visible foliar injury, starch and nutrient concentrations, bud formation and differences in O3 responses between lower, middle and upper sections of the canopy were determined. The potted saplings were unaffected by elevated O3 concentration, whereas the open-soil-grown trees showed a 3-38% reduction in shoot growth, a 22% reduction in number of overwintering buds, a 26-65% decrease in autumnal net photosynthesis, 30% and 20-23% reductions in starch and nitrogen concentrations of senescing leaves, respectively, and disturbances in stomatal conductance. The greater O3 sensitivity of open-soil-grown trees compared with potted saplings was a result of senescence-related physiological factors. First, a lower net photosynthesis to stomatal conductance ratio in open-soil-grown trees at the end of the season promoted O3 uptake and decreased photosynthetic gain, leading to the onset of visible foliar injuries. Second, decreased carbohydrate reserves may have resulted in deleterious carry-over effects arising from the reduced formation of over-wintering buds. Finally, the leaf-level O3 load was higher for open-soil-grown trees than for potted saplings because of slower leaf senescence in the trees. Thus, O3 sensitivity in European white birch increases with increasing exposure time and tree size. PMID:12750053

  15. Effect of season and variety on the differentiation of geographic growing origin of pistachios by stable isotope profiling.

    PubMed

    Anderson, Kim A; Smith, Brian W

    2006-03-01

    The objectives of this study were to demonstrate if seasonal or variety differences affected the feasibility of stable isotope profiling methods to differentiate the geographical growing regions of pistachios (Pistachia vera). Bulk carbon and nitrogen isotope analyses of approximately 150 pistachios samples were performed. Isotope ratios were determined using a stable isotope mass spectrometer. The pistachio samples analyzed were from the three major pistachio-growing regions: Turkey, Iran, and the United States (California). Geographic regions were well separated on the basis of isotope ratios. Seasonal effects were found to affect some isotopes for some regions. Pistachio varieties within specified geographic regions were not found to affect the discriminating power of stable isotopes, for the varieties tested. This paper reports the development of a simple chemical profiling method using bulk stable isotope ratios that may be widely applied to the determination of the geographic origin of foods. PMID:16506828

  16. Agriculture modifies the seasonal decline of breeding success in a tropical wild bird population

    PubMed Central

    Cartwright, Samantha J; Nicoll, Malcolm A C; Jones, Carl G; Tatayah, Vikash; Norris, Ken

    2014-01-01

    Habitat conversion for agriculture is a major driver of biodiversity loss, but our understanding of the demographic processes involved remains poor. We typically investigate the impacts of agriculture in isolation even though populations are likely to experience multiple, concurrent changes in the environment (e.g. land and climate change). Drivers of environmental change may interact to affect demography, but the mechanisms have yet to be explored fully in wild populations. Here, we investigate the mechanisms linking agricultural land use with breeding success using long-term data for the formerly Critically Endangered Mauritius kestrel Falco punctatus, a tropical forest specialist that also occupies agricultural habitats. We specifically focused on the relationship between breeding success, agriculture and the timing of breeding because the latter is sensitive to changes in climatic conditions (spring rainfall) and enables us to explore the interactive effects of different (land and climate) drivers of environmental change. Breeding success, measured as egg survival to fledging, declines seasonally in this population, but we found that the rate of this decline became increasingly rapid as the area of agriculture around a nest site increased. If the relationship between breeding success and agriculture was used in isolation to estimate the demographic impact of agriculture, it would significantly under-estimate breeding success in dry (early) springs and over-estimate breeding success in wet (late) springs. Analysis of prey delivered to nests suggests that the relationship between breeding success and agriculture might be due, in part, to spatial variation in the availability of native, arboreal geckos. Synthesis and applications. Agriculture modifies the seasonal decline in breeding success in this population. As springs are becoming wetter in our study area and since the kestrels breed later in wetter springs, the impact of agriculture on breeding success will

  17. Transcriptome profiling in fast versus slow-growing rainbow trout across seasonal gradients

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Circannual rhythms in vertebrates can influence a wide variety of physiological processes. Some notable examples include annual reproductive cycles and for poikilotherms, seasonal changes modulating growth. Increasing water temperature elevates growth rates in fishes, but increases i...

  18. Increases in Growing Season Length and Changes in Precipitation at Six Different Arctic and Subarctic Ecosystems from 1906-Present

    NASA Astrophysics Data System (ADS)

    Culler, L. E.; Finger, R.; Plane, E.; Ayres, M.; Virginia, R. A.

    2015-12-01

    Ecological dynamics across the Arctic are responding to rapid changes in climate. As a whole, the Arctic has warmed at approximately twice the rate of the rest of the world, but changes in temperature and precipitation experienced at regional and local scales are most important for coupled human-natural systems. In addition, biologically-relevant climate indices are necessary for quantifying ecological responses of terrestrial and aquatic systems to varying climate. We compared climatic changes at six different Arctic and sub-Arctic locations, including two in Greenland (Kangerlussuaq, Sisimiut), one in Sweden (Abisko), and three in Alaska (Barrow, Nome, Fairbanks). We amassed weather data (daily temperature and precipitation), dating as far back as 1906, from public-access databases and used these data to calculate indices such as length of growing season, growing season degree days (GDD), and growing season precipitation. Annual GDD increased at all locations (average of 13% increase in GDD since 1980), but especially in western Greenland (16 and 37% in Kangerlussuaq and Sisimiut, respectively). Changes in growing season precipitation were more variable, with only Barrow, AK and Abisko, Sweden experiencing increased precipitation. All other sites experienced stable or slightly declining precipitation. Increasing temperatures and relatively stable precipitation translates to increased evapotranspiration potential, which influences soil moisture, lake depth, vegetation, carbon emissions, and fire susceptibility. Understanding local and regional trends in temperature and precipitation can help explain observed phenological changes and other processes at population, community, and ecosystem levels. In addition, identification of locations most susceptible to future change will allow scientists to closely monitor their ecological dynamics, anticipate changes in coupled human-natural systems, and consider adaptation plans for the most rapidly changing systems.

  19. Seasonal changes in the performance of a catch crop for mitigating diffuse agricultural pollution.

    PubMed

    Kondo, K; Inoue, K; Fujiwara, T; Yamane, S; Yasutake, D; Maeda, M; Nagare, H; Akao, S; Ohtoshi, K

    2013-01-01

    An in situ technology for mitigating diffuse agricultural pollution using catch crops was developed for simultaneously preventing nitrate groundwater pollution, reducing nitrous oxide (N2O) gas emissions, and removing salts from the topsoil. Seasonal changes in the performance of a catch crop were investigated using lysimeters in a full-scale greenhouse experiment with 50 d cultivation of dent corn. Catch crop cultivation significantly reduced the leached mineral nitrogen by 89-91% in summer, 87-89% in spring, and 61-82% in winter, and it also significantly reduced the N2O emission by 68-84% in summer. The amounts of nitrogen uptake by the catch crop were remarkably higher than those of leached nitrogen and N2O emission in each season. Catch crop cultivation is a promising technology for mitigating diffuse agricultural pollution. PMID:23985506

  20. Seasonal Dynamics in Runoff Generation, Flowpaths and Phosphorus Mobilization From Reduced-till Agricultural Fields in Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Macrae, M. L.; van Esbroeck, C.; Brunke, R.; McKague, K.

    2014-12-01

    Reduced tillage systems used in agriculture have been shown to decrease losses of particulate phosphorus (P), but may increase the risk of dissolved P transport in some landscapes. Most of our knowledge of P losses from agricultural systems is based on observations made during the frost-free season and little is known about winter processes. Given the magnitude of the spring freshet in many regions, it is important to characterize P dynamics during this period. Discharge and P transport in overland flow and subsurface (tile) drainage were monitored at three reduced-till fields in southern Ontario, Canada for 18 months to (1) quantify runoff and P loads from fields; (2) characterize seasonality in the relative contributions of tile drainage and overland flow to runoff and P loads, and (3) demonstrate variable responses among different event types. Transport pathways were active throughout the non-growing season (NGS) and this period accounted for the majority of annual P loads over the study period. Drainage tiles were the dominant hydrologic pathway from fields throughout the study period, but were a small source of P when compared to P loss in overland flow. Overland flow was predominantly observed during winter thaws when ground frost was present. However, the magnitude and speciation of P losses during individual winter events were variable, and, were governed by a combination of antecedent conditions and precipitation characteristics. Given the importance of the NGS to annual P losses, we suggest that management steps should be taken to minimize the risk of losses during this period.

  1. Identifying spatial and seasonal patterns of river water quality in a semiarid irrigated agricultural Mediterranean basin.

    PubMed

    Darwiche-Criado, Nadia; Jiménez, Juan José; Comín, Francisco A; Sorando, Ricardo; Sánchez-Pérez, José Miguel

    2015-12-01

    A detailed understanding of the study area is essential to achieve key information and optimize the monitoring, analysis, and evaluation of water quality of natural ecosystems that have been highly transformed into agricultural areas. Using classification techniques like the hierarchical cluster analysis (CA) and partial triadic analysis (PTA), we assessed the sources of water pollution and the seasonal influence of human activities in water composition in a river basin from northeastern Spain. The results suggested that a strong connection existed between water quality and the seasonality of the human activities. The CA showed the spatial relationship between water chemistry and the adjacent land uses. The PTA associated the analyzed variables to their pollutant source. Electrical conductivity (EC), Cl(-), SO4(2-)-S, Na(+), and Mg(2+) ions were related with agricultural sources, whereas NH4(+)-N, PT, and PO4(3-)-P were linked with urban polluted sites. Concentration of NO3(-)-N was associated with urban land use. Differences in water composition according to the irrigation intensity were also found during the irrigation season. The statistical tools used in this work, especially the PTA, allowed us to jointly analyze the spatial and seasonal components of water pollutant trends. We obtained a more comprehensive knowledge of water quality patterns in the study area, which will be essential when taking measures to minimize the effects of water pollution. PMID:26429137

  2. Changes in growing season duration and productivity of northern vegetation inferred from long-term remote sensing data

    NASA Astrophysics Data System (ADS)

    Park, Taejin; Ganguly, Sangram; Tømmervik, Hans; Euskirchen, Eugénie S.; Høgda, Kjell-Arild; Rune Karlsen, Stein; Brovkin, Victor; Nemani, Ramakrishna R.; Myneni, Ranga B.

    2016-08-01

    Monitoring and understanding climate-induced changes in the boreal and arctic vegetation is critical to aid in prognosticating their future. We used a 33 year (1982–2014) long record of satellite observations to robustly assess changes in metrics of growing season (onset: SOS, end: EOS and length: LOS) and seasonal total gross primary productivity. Particular attention was paid to evaluating the accuracy of these metrics by comparing them to multiple independent direct and indirect growing season and productivity measures. These comparisons reveal that the derived metrics capture the spatio-temporal variations and trends with acceptable significance level (generally p < 0.05). We find that LOS has lengthened by 2.60 d dec‑1 (p < 0.05) due to an earlier onset of SOS (‑1.61 d dec‑1, p < 0.05) and a delayed EOS (0.67 d dec‑1, p < 0.1) at the circumpolar scale over the past three decades. Relatively greater rates of changes in growing season were observed in Eurasia (EA) and in boreal regions than in North America (NA) and the arctic regions. However, this tendency of earlier SOS and delayed EOS was prominent only during the earlier part of the data record (1982–1999). During the later part (2000–2014), this tendency was reversed, i.e. delayed SOS and earlier EOS. As for seasonal total productivity, we find that 42.0% of northern vegetation shows a statistically significant (p < 0.1) greening trend over the last three decades. This greening translates to a 20.9% gain in productivity since 1982. In contrast, only 2.5% of northern vegetation shows browning, or a 1.2% loss of productivity. These trends in productivity were continuous through the period of record, unlike changes in growing season metrics. Similarly, we find relatively greater increasing rates of productivity in EA and in arctic regions than in NA and the boreal regions. These results highlight spatially and temporally varying vegetation dynamics and are reflective of biome-specific responses

  3. Temperature and geographic attribution of change in the Taraxacum mongolicum growing season from 1990 to 2009 in eastern China's temperate zone

    NASA Astrophysics Data System (ADS)

    Chen, Xiaoqiu; Tian, Youhua; Xu, Lin

    2015-10-01

    Using leaf unfolding and leaf coloration data of a widely distributed herbaceous species, Taraxacum mongolicum, we detected linear trend and temperature response of the growing season at 52 stations from 1990 to 2009. Across the research region, the mean growing season beginning date marginal significantly advanced at a rate of -2.1 days per decade, while the mean growing season end date was significantly delayed at a rate of 3.1 days per decade. The mean growing season length was significantly prolonged at a rate of 5.1 days per decade. Over the 52 stations, linear trends of the beginning date correlate negatively with linear trends of spring temperature, whereas linear trends of the end date and length correlate positively with linear trends of autumn temperature and annual mean temperature. Moreover, the growing season linear trends are also closely related to the growing season responses to temperature and geographic coordinates plus elevation. Regarding growing season responses to temperature, a 1 °C increase in regional mean spring temperature results in an advancement of 2.1 days in regional mean growing season beginning date, and a 1 °C increase in regional mean autumn temperature causes a delay of 2.3 days in regional mean growing season end date. A 1 °C increase in regional annual mean temperature induces an extension of 8.7 days in regional mean growing season length. Over the 52 stations, response of the beginning date to spring temperature depends mainly on local annual mean temperature and geographic coordinates plus elevation. Namely, a 1 °C increase in spring temperature induces a larger advancement of the beginning date at warmer locations with lower latitudes and further west longitudes than at colder locations with higher latitudes and further east longitudes, while a 1 °C increase in spring temperature causes a larger advancement of the beginning date at higher than at lower elevations.

  4. Temperature and geographic attribution of change in the Taraxacum mongolicum growing season from 1990 to 2009 in eastern China's temperate zone.

    PubMed

    Chen, Xiaoqiu; Tian, Youhua; Xu, Lin

    2015-10-01

    Using leaf unfolding and leaf coloration data of a widely distributed herbaceous species, Taraxacum mongolicum, we detected linear trend and temperature response of the growing season at 52 stations from 1990 to 2009. Across the research region, the mean growing season beginning date marginal significantly advanced at a rate of -2.1 days per decade, while the mean growing season end date was significantly delayed at a rate of 3.1 days per decade. The mean growing season length was significantly prolonged at a rate of 5.1 days per decade. Over the 52 stations, linear trends of the beginning date correlate negatively with linear trends of spring temperature, whereas linear trends of the end date and length correlate positively with linear trends of autumn temperature and annual mean temperature. Moreover, the growing season linear trends are also closely related to the growing season responses to temperature and geographic coordinates plus elevation. Regarding growing season responses to temperature, a 1 °C increase in regional mean spring temperature results in an advancement of 2.1 days in regional mean growing season beginning date, and a 1 °C increase in regional mean autumn temperature causes a delay of 2.3 days in regional mean growing season end date. A 1 °C increase in regional annual mean temperature induces an extension of 8.7 days in regional mean growing season length. Over the 52 stations, response of the beginning date to spring temperature depends mainly on local annual mean temperature and geographic coordinates plus elevation. Namely, a 1 °C increase in spring temperature induces a larger advancement of the beginning date at warmer locations with lower latitudes and further west longitudes than at colder locations with higher latitudes and further east longitudes, while a 1 °C increase in spring temperature causes a larger advancement of the beginning date at higher than at lower elevations. PMID:25627826

  5. Monitoring seasonal progress of rice stubble burning in major rice growing districts of Haryana, India, using multidate AWiFS data

    NASA Astrophysics Data System (ADS)

    Yadav, M.; Prawasi, R.; Jangra, S.; Rana, P.; Kumari, K.; Lal, S.; Jakhar, K.; Sharma, S.; Hooda, R. S.

    2014-11-01

    The present paper describes the methodology and results of assessment of seasonal progress of rice stubble burning for 10 major rice growing districts of Haryana state in India. These 10 districts contribute about 84 per cent of total rice area of the state. As the rice fields are immediately required to be vacated for the sowing of next crop the farmers opt for mechanized harvesting and easy way out of burning the stubbles in the field. Such burning result in release of polluting gases and aerosols. Besides, the heating of the soil kills the useful micro-flora of the soil causing soil degradation. Multi-date AWiFS data from Resourcesat 1 and 2 satellites acquired between October 16, 2013 to November 26, 2013 were used for estimating paddy stubble burning areas at different intervals for the year 2013 crop growing season. In season collected ground truth data using hand held GPS along with field photographs were used to identify paddy stubble burning areas and other land features. Complete enumeration approach and Iterative Self-organizing Data Analysis Technique (ISODATA) unsupervised classifier was used for digital analysis. Normalized Difference Vegetation Index (NDVI) of each date was also used with other spectral bands of temporal images. To improve the classification accuracy the non-agricultural areas were masked out. The area was estimated by computing pixels under the classified image mask. Progress of paddy stubble burning was estimated at different intervals for the year 2013 using available cloud free multi-date IRS-P6 AWiFS data to identify the crucial period when stubbles burning takes place in major area so that preventive measures can be taken to curb the menace.

  6. Fertilizer Application Timing Influences Greenhouse Gas Fluxes Over a Growing Season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microbial production and consumption of greenhouse gases (GHG) is influenced by temperature and nutrients, especially during the first few weeks after agricultural fertilization. The effect of fertilization on GHG fluxes should be sensitive to environmental conditions during and shortly after appli...

  7. Nitrogen Loss from a Mixed Land Use Watershed as Influenced by Hydrology and Growing Seasons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-point nitrogen loss from agriculture is an environmental concern among scientists, decision-makers, and the public. This study investigated nitrate-N and total N losses from a mixed land use watershed (39.5 ha) as influenced by hydrology (flow type, runoff volume, storm sizes, and precipitation ...

  8. Impacts and uses of seasonal and intraseasonal predictions in the business community with an emphasis on the energy and agricultural industries

    NASA Astrophysics Data System (ADS)

    Streit, D.; Murnane, R.

    2003-04-01

    Almost any industry can benefit financially from accurate seasonal and intraseasonal predictions by determining threats to profits and taking out derivative insurance. However, the energy and agricultural industries stand to gain from these forecasts in many more ways and are therefore already using them in their decision support systems. Earth Satellite Corporation is one of the leading companies providing seasonal and intraseasonal forecasts to customers in these communities. The end users in both can be broadly divided into producers and traders, each with specific needs and applications. In this presentation, we describe those needs and applications based on our 30 years of experience. The basic difference between traders and producers in both groups is that traders will use a long-range forecast to define their overall trading strategy for a season, while producers will use the forecast more in a tactical sense to either cut their losses or maximize their profits. For example, agricultural producers will change the crops to be planted if they know a dry growing season is expected. In the energy industry, the amount of natural gas or heating oil stored by producers for the upcoming heating season is driven by forecasts. Traders in both industries will apply a more aggressive or cautious approach to the positions they take based on the forecasts. The rest of the presentation will describe other several other applications in retail, transportation, and the housing industry.

  9. High-Frequency Measurements of Methane Ebullition Over a Growing Season at a Temperate Peatland Site

    NASA Technical Reports Server (NTRS)

    Goodrich, Jordan P.; Varner, Ruth K.; Frolking, Steve; Duncan, Bryan N.; Crill, Patrick M.

    2011-01-01

    Bubbles can contribute a significant fraction of methane emissions fr om wetlands; however the range of reported fractions is very large an d accurate characterization of this pathway has proven difficult. Her e we show that continuous automated flux chambers combined with an in tegrated cavity output spectroscopy (ICOS) instrument allow us to qua ntify both CH4 ebullition rate and magnitude. For a temperate poor f en in 2009, ebullition rate varied on hourly to seasonal time scales. A diel pattern in ebullition was identified with peak release occurr ing between 20:00 and 06:00 local time, though steady fluxes (i.e., t hose with a linear increase in chamber headspace CH4 concentration) d id not exhibit diel variability. Seasonal mean ebullition rates peake d at 843.5 +/- 384.2 events m(exp -2)/d during the summer, with a me an magnitude of 0.19 mg CH4 released in each event.

  10. Landscape controls on the timing of spring, autumn, and growing season length in mid-Atlantic forests

    USGS Publications Warehouse

    Elmore, A.J.; Guinn, S.M.; Minsley, B.J.; Richardson, A.D.

    2012-01-01

    The timing of spring leaf development, trajectories of summer leaf area, and the timing of autumn senescence have profound impacts to the water, carbon, and energy balance of ecosystems, and are likely influenced by global climate change. Limited field-based and remote-sensing observations have suggested complex spatial patterns related to geographic features that influence climate. However, much of this variability occurs at spatial scales that inhibit a detailed understanding of even the dominant drivers. Recognizing these limitations, we used nonlinear inverse modeling of medium-resolution remote sensing data, organized by day of year, to explore the influence of climate-related landscape factors on the timing of spring and autumn leaf-area trajectories in mid-Atlantic, USA forests. We also examined the extent to which declining summer greenness (greendown) degrades the precision and accuracy of observations of autumn offset of greenness. Of the dominant drivers of landscape phenology, elevation was the strongest, explaining up to 70% of the spatial variation in the onset of greenness. Urban land cover was second in importance, influencing spring onset and autumn offset to a distance of 32 km from large cities. Distance to tidal water also influenced phenological timing, but only within ~5 km of shorelines. Additionally, we observed that (i) growing season length unexpectedly increases with increasing elevation at elevations below 275 m; (ii) along gradients in urban land cover, timing of autumn offset has a stronger effect on growing season length than does timing of spring onset; and (iii) summer greendown introduces bias and uncertainty into observations of the autumn offset of greenness. These results demonstrate the power of medium grain analyses of landscape-scale phenology for understanding environmental controls on growing season length, and predicting how these might be affected by climate change.

  11. Partitioning the grapevine growing season in the Douro Valley of Portugal: accumulated heat better than calendar dates

    NASA Astrophysics Data System (ADS)

    Real, António C.; Borges, José; Cabral, J. Sarsfield; Jones, Gregory V.

    2015-08-01

    Temperature and water status profiles during the growing season are the most important factors influencing the ripening of wine grapes. To model weather influences on the quality and productivity of the vintages, it is necessary to partition the growing season into smaller growth intervals in which weather variables are evaluated. A significant part of past and ongoing research on the relationships between weather and wine quality uses calendar-defined intervals to partition the growing season. The phenology of grapevines is not determined by calendar dates but by several factors such as accumulated heat. To examine the accuracy of different approaches, this work analyzed the difference in average temperature and accumulated precipitation using growth intervals with boundaries defined by means of estimated historical phenological dates and intervals defined by means of accumulated heat or average calendar dates of the Douro Valley of Portugal. The results show that in situations where there is an absence of historical phenological dates and/or no available data that makes the estimation of those dates possible, it is more accurate to use grapevine heat requirements than calendar dates to define growth interval boundaries. Additionally, we analyzed the ability of the length of growth intervals with boundaries based on grapevine heat requirements to differentiate the best from the worst vintage years with the results showing that vintage quality is strongly related to the phenological events. Finally, we analyzed the variability of growth interval lengths in the Douro Valley during 1980-2009 with the results showing a tendency for earlier grapevine physiology.

  12. [Effects of precipitation variation on growing seasonal dynamics of soil microbial biomass in broadleaved Korean pine mixed forest].

    PubMed

    Wang, Ning; Wang, Mei-ju; Li, Shi-lan; Wang, Nan-nan; Feng, Fu-juan; Han, Shi-jie

    2015-05-01

    Broadleaved Korean pine mixed forest is the zonal climax vegetation in Northeast China and it plays a significant role in maintaining the ecological security. Changbai Mountains is a suitable region to study the positive and negative feedback mechanisms of temperate forest for precipitation variation. This study analyzed responses of soil microbial biomass carbon (SMBC) and microbial biomass nitrogen (SMBN) to precipitation variation (± 30%) in original broadleaved Korean pine mixed forest of Changbai Mountains. The results showed that, during the growing seasons (from May to September), the averages of SMBC and SMBN were 879.09 and 100.03 mg · kg(-1), respectively. Moreover, both of these two parameters gradually decreased with the soil depth. The contents of SMBC and SMBN all increased with the increasing precipitation, and the changes of SMBC and SMBN in the 0-5 cm soil layer were stronger than in the 5-10 cm soil layer. The value of SMBC/SMBN declined with the increase of precipitation. The precipitation variation significantly influenced the means of SMBC and SMBN. Compared with precipitation reduction, precipitation enhancement affected the indices much significantly. Both SMBC and SMBN showed similar seasonal patterns, which were the lowest in May, and after that, they increased and then decreased and increased again, showing 1-2 peaks in the growing season. However, the value and occurring time of the peaks varied with the precipitation and soil layer, and the seasonal variations of SMBC and SMBN in the 0-5 cm soil layer were higher than in the 5-10 cm soil layer. SMBC and SMBN had significant positive correlation with organic matter and total nitrogen content. The variances of soil physical and chemical properties caused by precipitation variation were closely related with the difference in spatial-temporal patterns of the soil microbial biomass in the forest. In conclusion, the precipitation variations could cause the change of the soil microbial

  13. Where the Grass Grows Again: Knowledge Exchange in the Sustainable Agriculture Movement.

    ERIC Educational Resources Information Center

    Hassanein, Neva; Kloppenburg, Jack R., Jr.

    1995-01-01

    Intensive rotational grazing by Wisconsin dairy farmers represents a local expression of the sustainable agriculture movement. Contrary to interpretations that view local knowledge in agriculture as idiosyncratic, these graziers use horizontal forms of organizing and information exchange to overcome the limits of personal experience and share…

  14. The variation of methane flux rates from boreal tree species at the beginning of the growing season

    NASA Astrophysics Data System (ADS)

    Haikarainen, Iikka; Halmeenmäki, Elisa; Machacova, Katerina; Pihlatie, Mari

    2016-04-01

    Boreal forests are considered as net sink for atmospheric methane (CH4) because of the CH4 oxidizing bacteria in the aerobic soil layer. However, within the last decades it has become more evident that trees play an important role in the global CH4 budget by offering pathways for anaerobically produced CH4 from deeper soil layers to the atmosphere. Furthermore, trees may also act as independent sources of CH4. To confirm magnitude, variability and the origin of the tree mediated CH4 emissions more research is needed, especially in boreal forests which have been in a minority in such investigation. We measured tree stem and shoot CH4 exchange of three boreal tree species at the beginning of the growing season (13.4.-13.6.2015) at SMEAR II station in Hyytiälä, located in southern Finland (61° 51'N, 24° 17'E, 181 asl). The fluxes were measured from silver birch (Betula pendula), downy birch (B. pubescens) and Norway spruce (Picea abies) on two sites with differing soil type and characteristics (paludified and mineral soil), vegetation and forest structure by using the static chamber technique. Scaffold towers were used for measurements at multiple stem heights and shoots. The aim was to study the vertical profile of CH4 fluxes at stem and shoot level and compare these fluxes among the studied species, and to observe temporal changes in CH4 flux over the beginning of the growing season. We found that all the trees emitted CH4 from their stems and shoots. Overall, the birches showed higher emissions compared to the spruces. The emission rates were considerably larger in the lower parts of the birch stems than upper parts, and these emissions increased during the growing season. The spruces had more variation in the stem CH4 flux, but the emission rates of the upper parts of the stem exceeded the birch emissions at the same height. The shoot fluxes of all the studied trees indicated variable CH4 emissions without a clear pattern regarding the vertical profile and

  15. Exploring the correlation between Southern Africa NDVI and Pacific sea surface temperatures: Results for the 1998 maize growing season

    USGS Publications Warehouse

    Verdin, J.; Funk, C.; Klaver, R.; Roberts, D.

    1999-01-01

    Several studies have identified statistically significant correlations between Pacific sea surface temperature anomalies and NDVI anomalies in Southern Africa. The potential predictive value of the relationship was explored for the 1998 maize growing season. Cross-validation techniques suggested a more useful relationship for regions of wet anomaly than for regions of dry anomaly. Observed 1998 NDVI anomaly patterns were consistent with this result. Wet anomalies were observed as expected, but wide areas of expected dry anomalies exhibited average or above-average greeness.

  16. Seasonal Patterns in Microbial Community Composition in Denitrifying Bioreactors Treating Subsurface Agricultural Drainage.

    PubMed

    Porter, Matthew D; Andrus, J Malia; Bartolerio, Nicholas A; Rodriguez, Luis F; Zhang, Yuanhui; Zilles, Julie L; Kent, Angela D

    2015-10-01

    Denitrifying bioreactors, consisting of water flow control structures and a woodchip-filled trench, are a promising approach for removing nitrate from agricultural subsurface or tile drainage systems. To better understand the seasonal dynamics and the ecological drivers of the microbial communities responsible for denitrification in these bioreactors, we employed microbial community "fingerprinting" techniques in a time-series examination of three denitrifying bioreactors over 2 years, looking at bacteria, fungi, and the denitrifier functional group responsible for the final step of complete denitrification. Our analysis revealed that microbial community composition responds to depth and seasonal variation in moisture content and inundation of the bioreactor media, as well as temperature. Using a geostatistical analysis approach, we observed recurring temporal patterns in bacterial and denitrifying bacterial community composition in these bioreactors, consistent with annual cycling. The fungal communities were more stable, having longer temporal autocorrelations, and did not show significant annual cycling. These results suggest a recurring seasonal cycle in the denitrifying bioreactor microbial community, likely due to seasonal variation in moisture content. PMID:25910602

  17. Verification of Satellite Radar Remote Sensing Based Estimates of Boreal and Subalpine Growing Seasons Using an Ecosystem Process Model and Surface Biophysical Measurement Network Information

    NASA Astrophysics Data System (ADS)

    Kimball, J. S.; McDonald, K. C.; Running, S. W.; Zimmermann, R.

    2002-12-01

    We employ daily surface Radar backscatter data from the SeaWinds Ku-band Scatterometer onboard Quikscat to estimate landscape freeze-thaw state and associated length of the seasonal non-frozen period as a surrogate for determining the annual growing season across boreal and subalpine regions of North America for 2000 and 2001. We compare these results with estimates of growing season length derived from a network of surface stations, utilizing BIOME-BGC stand-level ecosystem process model simulations, site sap flow and tower eddy flux net CO2 exchange measurements for a network of mature evergreen coniferous forest stands. Remote sensing based estimates of spatial patterns in the timing of seasonal freeze-thaw vary by more than 8 weeks, while associated estimates of growing season length span more than 14 weeks across the region. Inter-annual variability between 2000 and 2001 is found to be on the order of 1-4 weeks. Remote sensing estimates of growing season initiation and length are found to be well correlated with both site measurements and model simulations. Remote sensing measurements of the end of the seasonal non-frozen period are also found to be consistent with site based temperature measurements, but not with site based estimates of growing season termination. These findings are attributed to a relatively strong dependence of the onset of the growing season to snowmelt and associated soil thaw in spring and the relative importance of additional factors such as light availability and day length in controlling growing season termination. This work was performed at the University of Montana, and at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  18. Estimation of Migrant and Seasonal Agricultural Workers in Iowa, Kansas, Missouri and Nebraska: Public Health Service Region VII. Final Report.

    ERIC Educational Resources Information Center

    Slesinger, Doris P.; Cautley, Eleanor

    This research project estimated migrant and seasonal agricultural workers in four Midwestern States in 1988, using the Public Health Service's definitions of such workers. Researchers collected federal agricultural data and state reports on migrant education programs and crop patterns, and considered other potential data sources. Numerous…

  19. Impact of Faba Bean-Seed Rhizobial Inoculation on Microbial Activity in the Rhizosphere Soil during Growing Season.

    PubMed

    Siczek, Anna; Lipiec, Jerzy

    2016-01-01

    Inoculation of legume seeds with Rhizobium affects soil microbial community and processes, especially in the rhizosphere. This study aimed at assessing the effect of Rhizobium inoculation on microbial activity in the faba bean rhizosphere during the growing season in a field experiment on a Haplic Luvisol derived from loess. Faba bean (Vicia faba L.) seeds were non-inoculated (NI) or inoculated (I) with Rhizobium leguminosarum bv. viciae and sown. The rhizosphere soil was analyzed for the enzymatic activities of dehydrogenases, urease, protease and acid phosphomonoesterase, and functional diversity (catabolic potential) using the Average Well Color Development, Shannon-Weaver, and Richness indices following the community level physiological profiling from Biolog EcoPlate™. The analyses were done on three occasions corresponding to the growth stages of: 5-6 leaf, flowering, and pod formation. The enzymatic activities were higher in I than NI (p < 0.05) throughout the growing season. However, none of the functional diversity indices differed significantly under both treatments, regardless of the growth stage. This work showed that the functional diversity of the microbial communities was a less sensitive tool than enzyme activities in assessment of rhizobial inoculation effects on rhizosphere microbial activity. PMID:27213363

  20. Impact of Faba Bean-Seed Rhizobial Inoculation on Microbial Activity in the Rhizosphere Soil during Growing Season

    PubMed Central

    Siczek, Anna; Lipiec, Jerzy

    2016-01-01

    Inoculation of legume seeds with Rhizobium affects soil microbial community and processes, especially in the rhizosphere. This study aimed at assessing the effect of Rhizobium inoculation on microbial activity in the faba bean rhizosphere during the growing season in a field experiment on a Haplic Luvisol derived from loess. Faba bean (Vicia faba L.) seeds were non-inoculated (NI) or inoculated (I) with Rhizobium leguminosarum bv. viciae and sown. The rhizosphere soil was analyzed for the enzymatic activities of dehydrogenases, urease, protease and acid phosphomonoesterase, and functional diversity (catabolic potential) using the Average Well Color Development, Shannon-Weaver, and Richness indices following the community level physiological profiling from Biolog EcoPlate™. The analyses were done on three occasions corresponding to the growth stages of: 5–6 leaf, flowering, and pod formation. The enzymatic activities were higher in I than NI (p < 0.05) throughout the growing season. However, none of the functional diversity indices differed significantly under both treatments, regardless of the growth stage. This work showed that the functional diversity of the microbial communities was a less sensitive tool than enzyme activities in assessment of rhizobial inoculation effects on rhizosphere microbial activity. PMID:27213363

  1. Evaluation of the onset and length of growing season to define planting date—`a case study for Mali (West Africa)'

    NASA Astrophysics Data System (ADS)

    Akinseye, F. M.; Agele, S. O.; Traore, P. C. S.; Adam, M.; Whitbread, A. M.

    2016-05-01

    The agroecological zones (AEZ) of Mali fall within the semi-arid climate, the ability to determine efficiently or predict accurately the onset of growing season (OGS), and length of growing season (LGS) cannot be over-emphasized due to highly variable rainfall pattern and the dependence of smallholder farmers practising on rainfed farming agriculture. In this study, we determined the most suitable method for predicting the onset date of rainfall across AEZ that fitted with the planting windows of major cereal crops (maize, millet, and sorghum). Using long-term daily rainfall records from 22 meteorological stations spread across AEZ of Mali, four (4) known methods were applied to determine the onset dates of the rain. The mean onset dates were statistically compared with the farmer's planting window for the selected weather stations to determine the suitable dates of OGS and LGS. The hypothesis considered a time lag minimum of 7 days between the mean onset date and traditional farmer sowing dates for the crops. Then, the preferred method was used to estimate OGS based on early, normal and late dates respectively across the stations. Also, the estimated LGS according to each zone was evaluated using probability distribution chart with duration to maturity for varieties of the same crops. The results showed that Def_4 was found appropriate for Sahelian and Sudano-Sahelian zones; Def_3 satisfied the criteria and exhibited superior capacity into farmer's average planting date over Sudanian and Guinea Savannah zones. These results have an important application in cropping systems in order to prevent crop failure and ensure a better choice of crop variety according to LGS under climate variability and change being experienced across Mali.

  2. Controls for ecosystem methane exchange are time-scale specifc and shift during the growing season of a temperate fen

    NASA Astrophysics Data System (ADS)

    Sachs, T.; Koebsch, F.; Jurasinski, G.; Koch, M.; Hofmann, J.; Glatzel, S.

    2014-12-01

    Wetlands are the largest natural sources for atmospheric methane (CH4). In wetlands with permanent shallow inundation, the seasonal variation of CH4 exchange is mainly controlled by temperature and phenology. In addition, ecosystem CH4 exchange varies considerably on smaller temporal scales such as days or weeks. Several single processes that control CH4 emissions on the local soil-plant-atmosphere continuum are well investigated, but their interaction on ecosystem level is not well understood yet. We applied wavelet analysis to a quasi-continuous Eddy Covariance CH4 flux time series to describe the temporal variation of ecosystem CH4 exchange within the growing season of a permanently inundated temperate fen. Moreover, we addressed time scale-specific controls and investigated whether their impact changes during the course of the growing season. On large time scales of two weeks to three months, temperature explained most of the variation in ecosystem CH4 exchange. In general, the temperature in the shallow water column had the largest impact as explanatory variable, however, air temperature and soil temperature became increasingly important as explanatory variables when water level dropped slightly up to June. The diurnal variation of ecosystem CH4 exchange shifted during the course of the growing season: During a short time period at the end of April, plant activity (expressed by canopy photosynthesis) caused a diurnal variation of ecosystem CH4 exchange with peak time around noon. In the following weeks, the daily cycle of convective mixing within the water column (expressed by the water temperature gradient) gradually gained importance and caused high night-time CH4 emissions, thereby levelling off the diurnal CH4 emission pattern. Moreover, shear-induced turbulence caused short-term fluctuations of ecosystem CH4 exchange on time scales up to two hours. Our study highlights the need for multi-scale approaches that consider the non-stationarity of the

  3. Controls for multi-scale temporal variation in ecosystem methane exchange during the growing season of a permanently inundated fen

    NASA Astrophysics Data System (ADS)

    Koebsch, Franziska; Jurasinski, Gerald; Koch, Marian; Hofmann, Joachim; Glatzel, Stephan

    2014-05-01

    Temperature and phenology trigger seasonal variation of CH4 emissions in many ecosystems. However, ecosystem CH4 exchange varies also considerably on smaller temporal scales such as days or weeks. Indeed, we are aware of many processes that control CH4 emissions on the local soil-plant-atmosphere continuum, but their interaction on ecosystem level is not well understood yet. We used a quasi-continuous Eddy Covariance CH4 flux time series and wavelet analysis to describe the temporal variation of ecosystem CH4 exchange within the growing season of a permanently inundated temperate fen. Moreover, we assigned time scale-specific controls and investigated whether their impact changes during the course of the growing season. Water/soil temperature correlated with ecosystem CH4 exchange at time scales of 6-11 and 22 days which exceeds the time scales that are typically associated with the passage of weather fronts. The low response time might be due to the high heat capacity of the water column. On a daily scale, shear-induced turbulence (presented by friction velocity) and plant activity (presented by canopy photosynthesis) caused a diurnal variation of ecosystem CH4 exchange with peak time around noon. However, this pattern was apparent only at the beginning of the growing season (April/May). In the following, convective mixing of the water column (presented by the water temperature gradient) gradually gained importance and caused high night-time CH4 emissions, thereby levelling off the diurnal CH4 emission pattern. Our study highlights the need for multi-scale approaches that consider the non-stationarity of the underlying processes to adequately describe the complexity of ecosystem CH4 exchange. Moreover, we show that CH4 release processes such as convective mixing of the water column which has been mainly known from aquatic ecosystems until recently (Godwin et al. 2013), might be also of importance in shallowly flooded terrestrial ecosystems. Citation: Godwin CM, Mc

  4. Improving crop biomass through asynchronous assimilation of LAI and soil moisture during multiple growing seasons of corn

    NASA Astrophysics Data System (ADS)

    Bongiovanni, T. E.; Nagarajan, K.; Jones, J. W.; Monsivais Huertero, A.; Judge, J.

    2010-12-01

    Crop biomass is an important indicator of the health of a plant and is also critical for various remote sensing algorithms. In addition, it determines water uptake by the roots, affecting the root zone soil moisture (RZSM). Typically, crop models are used to simulate growth and development in a growing season and estimate biomass and yield. However large uncertainties in these estimates occur over time due to errors in computation, initialization conditions, forcings, and model parameters. Such uncertainties can be significantly reduced by assimilating in situ and/or remotely sensed observations. Satellite-based LAI and near-surface soil moisture (SM) are available weekly and 3 days, respectively. In this study, an EnKF-based assimilation algorithm was implemented to improve crop biomass using the Decision Support System for Agrotechnology Transfer (DSSAT) Cropping System Model. In situ observations of weekly LAI and every 3-day SM were assimilated asynchronously to update model estimates of LAI, RZSM, and crop biomass. The in situ observations were obtained from intensive field experiments during three seasons of sweet corn grown in North Central Florida. The impact of different assimilation scenarios for crop biomass was determined by the root mean squared difference and the standard deviation between the model estimates and observations during the seasons.

  5. Investigating the Persistence of a Snowpack Sublimation Stable Isotope Signal in Tree Xylem Water during the Growing Season

    NASA Astrophysics Data System (ADS)

    Schulze, E. S.; Bowling, D. R.

    2014-12-01

    Previous work identified a riparian meadow in the Rocky Mountains where streamside box elder (Acer negundo) trees did not use stream water, the most reliable and readily available source. A follow-up study showed that the water used by trees appears to be more evaporatively enriched than all available measured sources, including stream water, precipitation-derived soil water, and groundwater. While it is unlikely that there is a missing pool of water these trees are accessing, they may be tapping into a distinct subset of the bulk soil water available, possibly derived from much colder and older snowmelt. In this study, we investigated whether snowpack sublimation and subsequent melt water may impart an enriched isotopic signature that persists throughout the following growing season in less-mobile soil water pools. Profile samples of the snowpack, bulk melt water, and early season soil lysimeter water were collected throughout the winter and analyzed for hydrogen and oxygen stable isotopes. As snow began to melt in the spring, water samples for isotope analysis were taken from soil profiles, stream water, groundwater, and stems. Although sublimation likely occurred at the site, such processes did not impart an evaporative isotope enrichment on the snowpack throughout the season. Both snow pack and melt water remained closely tied to the local meteoric water line as they infiltrated soil. These findings suggest that snowpack sublimation processes preceding melt water infiltration are not the source of evaporative enrichment in tree water at our site.

  6. A comparative synoptic climatology of cool-season rainfall in major grain-growing regions of southern Australia

    NASA Astrophysics Data System (ADS)

    Pook, Michael J.; Risbey, James S.; McIntosh, Peter C.

    2014-08-01

    Two distinct synoptic weather systems, cut-off lows and fronts, deliver most of the cool-season rainfall to the cropping regions of southern Australia. A comparative synoptic climatology of daily rainfall events over approximately five decades reveals both spatial and temporal variations of the dominant synoptic types. The rainfall characteristics and associated large-scale drivers differ between the two synoptic types. Understanding regional rainfall depends on understanding these differences. Cut-off lows contribute one half of growing season rainfall in southeast Australia, while frontal systems associated with Southern Ocean depressions contribute about a third. The proportions are reversed in the Central Wheat Belt (CWB) of Western Australia where Southern Ocean fronts are the dominant source of growing season rainfall. In the southern island state of Tasmania, topography strongly influences the outcome with cut-off lows contributing about half the rainfall near the east coast and fronts dominating a short distance to the west. Cut-off lows generally contribute their highest proportion of rainfall in the austral autumn and spring while frontal rainfall is at its maximum in late winter. Cut-off low rainfall contributes more strongly in percentage terms to the recent decline in rainfall. The distribution of synoptic types is explained by the dominant long-wave structure in the winter half of the year. The major trough near Western Australia favours frontogenesis to the southwest of the CWB but fronts moving out of the region encounter a persistent meridional ridge in the Tasman Sea where there is a high frequency of blocking events.

  7. Effects of grazing on ecosystem CO₂ exchange in a meadow grassland on the Tibetan Plateau during the growing season.

    PubMed

    Chen, Ji; Shi, Weiyu; Cao, Junji

    2015-02-01

    Effects of human activity on ecosystem carbon fluxes (e.g., net ecosystem exchange (NEE), ecosystem respiration (R(eco)), and gross ecosystem exchange (GEE)) are crucial for projecting future uptake of CO2 in terrestrial ecosystems. However, how ecosystem that carbon fluxes respond to grazing exclusion is still under debate. In this study, a field experiment was conducted to study the effects of grazing exclusion on R(eco), NEE, and GEE with three treatments (free-range grazing (FG) and grazing exclusion for 3 and 5 years (GE3 and GE5, respectively)) in a meadow grassland on the Tibetan Plateau. Our results show that grazing exclusion significantly increased NEE by 47.37 and 15.84%, and R eco by 33.14 and 4.29% under GE3 and GE5 plots, respectively, although carbon sinks occurred in all plots during the growing season, with values of 192.11, 283.12, and 222.54 g C m(-2) for FG, GE3, and GE5, respectively. Interestingly, grazing exclusion increased temperature sensitivity (Q10) of R eco with larger increases at the beginning and end of growing season (i.e., May and October, respectively). Soil temperature and soil moisture were key factors on controlling the diurnal and seasonal variations of R(eco), NEE, and GEE, with soil temperature having a stronger influence. Therefore, the combined effects of grazing and temperature suggest that grazing should be taken into consideration in assessing global warming effects on grassland ecosystem CO2 exchange. PMID:25355630

  8. Effects of Grazing on Ecosystem CO2 Exchange in a Meadow Grassland on the Tibetan Plateau During the Growing Season

    NASA Astrophysics Data System (ADS)

    Chen, Ji; Shi, Weiyu; Cao, Junji

    2015-02-01

    Effects of human activity on ecosystem carbon fluxes (e.g., net ecosystem exchange (NEE), ecosystem respiration ( R eco), and gross ecosystem exchange (GEE)) are crucial for projecting future uptake of CO2 in terrestrial ecosystems. However, how ecosystem that carbon fluxes respond to grazing exclusion is still under debate. In this study, a field experiment was conducted to study the effects of grazing exclusion on R eco, NEE, and GEE with three treatments (free-range grazing (FG) and grazing exclusion for 3 and 5 years (GE3 and GE5, respectively)) in a meadow grassland on the Tibetan Plateau. Our results show that grazing exclusion significantly increased NEE by 47.37 and 15.84 %, and R eco by 33.14 and 4.29 % under GE3 and GE5 plots, respectively, although carbon sinks occurred in all plots during the growing season, with values of 192.11, 283.12, and 222.54 g C m-2 for FG, GE3, and GE5, respectively. Interestingly, grazing exclusion increased temperature sensitivity ( Q 10) of R eco with larger increases at the beginning and end of growing season (i.e., May and October, respectively). Soil temperature and soil moisture were key factors on controlling the diurnal and seasonal variations of R eco, NEE, and GEE, with soil temperature having a stronger influence. Therefore, the combined effects of grazing and temperature suggest that grazing should be taken into consideration in assessing global warming effects on grassland ecosystem CO2 exchange.

  9. Monitoring Seasonal Evapotranspiration in Vulnerable Agriculture using Time Series VHSR Satellite Data

    NASA Astrophysics Data System (ADS)

    Dalezios, Nicolas; Spyropoulos, Nicos V.; Tarquis, Ana M.

    2015-04-01

    The research work stems from the hypothesis that it is possible to perform an estimation of seasonal water needs of olive tree farms under drought periods by cross correlating high spatial, spectral and temporal resolution (~monthly) of satellite data, acquired at well defined time intervals of the phenological cycle of crops, with ground-truth information simultaneously applied during the image acquisitions. The present research is for the first time, demonstrating the coordinated efforts of space engineers, satellite mission control planners, remote sensing scientists and ground teams to record at specific time intervals of the phenological cycle of trees from ground "zero" and from 770 km above the Earth's surface, the status of plants for subsequent cross correlation and analysis regarding the estimation of the seasonal evapotranspiration in vulnerable agricultural environment. The ETo and ETc derived by Penman-Montieth equation and reference Kc tables, compared with new ETd using the Kc extracted from the time series satellite data. Several vegetation indices were also used especially the RedEdge and the chlorophyll one based on WorldView-2 RedEdge and second NIR bands to relate the tree status with water and nutrition needs. Keywords: Evapotransipration, Very High Spatial Resolution - VHSR, time series, remote sensing, vulnerability, agriculture, vegetation indeces.

  10. Growing season boundary layer climate and surface exchanges in a subarctic lichen woodland

    NASA Technical Reports Server (NTRS)

    Fitzjarrald, David R.; Moore, Kathleen E.

    1994-01-01

    Between June and August 1990, observations were made at two surface micrometeorological towers near Schefferville Quebec (54 deg 52 min N, 66 deg 40.5 min W), one in a fen and one in the subarctic lichen woodland, and at four surface climatological stations. Data from these surface stations were supplemented by regular radiosonde launches. Supporting measurements of radiative components and soil temperatures allowed heat and moisture balances to be obtained at two sites. The overall surface meteorological experiment design and results of micrometeorological observations made on a 30-m tower in the lichen woodland are presented here. Seasonal variation in the heat and water vapor transport characteristics illustrate the marked effect of the late summer climatological shift in air mass type. During the first half of the summer, average valley sidewalls only 100 m high are sufficient to channel winds along the valley in the entire convective boundary layer. Channeling effects at the surface, known for some time at the long-term climate station in Schefferville, are observed both at ridge top and in the valley, possibly the response of the flow to the NW-SE orientation of valleys in the region. Diurnal surface temperature amplitude at ridge top (approximately equal to 10 C) was found to be half that observed in the valley. Relatively large differences in precipitation among these stations and the climatological station at Schefferville airport were observed and attributed to the local topography. Eddy correlation observations of the heat, moisture and momentum transports were obtained from a 30-m tower above a sparse (approximately equal to 616 stems/ha) black spruce lichen woodland. Properties of the turbulent surface boundary layer agree well with previous wind tunnel studies over idealized rough surfaces. Daytime Bowen ratios of 2.5-3 are larger than those reported in previous studies. Surface layer flux data quality was assessed by looking at the surface layer heat

  11. Seasonal energy requirements and thermoregulation of growing pouched mice, Saccostomus campestris (Cricetidae)

    NASA Astrophysics Data System (ADS)

    Ellison, G. T. H.; Skinner, J. D.

    1991-06-01

    Pouched mice ( Saccostomus campestris) were born in captivity during January and March and subsequently maintained under long photoperiod (14 h light: 10 h dark) at 25°C. During their first winter (July) and the following summer (January) the pouched mice were exposed to natural photoperiod in an unheated laboratory for 3 weeks prior to measurement. The pouched mice continued to grow during the study, and were significantly heavier after summer exposure than after winter exposure 6 months earlier. Although this increase in body mass would result in a decline in their surface area to volume ratio there was no significant decline in minimal thermal conductance ( C m) and winter-exposed pouched mice had a relatively lower C m than expected. Meanwhile the smaller, winter-exposed animals displayed a significantly higher capacity for non-shivering thermogenesis, together with higher levels of basal metabolism than summer individuals. These differences were not solely attributable to the contrasting body mass of each group and it is therefore clear that S. campestris can increase thermoregulatory heat production, and modify heat loss following exposure to short photoperiod and cold during their first winter. Despite the significant increase in metabolism, the overall energy requirements of small, winter-exposed animals were significantly lower than those for heavier pouched mice following exposure to summer conditions. These results suggest that growing pouched mice can effectively adapt to lower temperature conditions during their first winter, yet accrue considerable overall savings in total energy requirements as a result of their smaller body mass.

  12. Climatic warming above the Arctic Circle: are there trends in timing and length of the thermal growing season in Murmansk Region (Russia) between 1951 and 2012?

    NASA Astrophysics Data System (ADS)

    Blinova, Ilona; Chmielewski, Frank-Michael

    2015-06-01

    Anomalies in the timing of the thermal growing season have become obvious in the NE part of Fennoscandia since 2000. They are in accordance with climatic changes reported for Europe and Fennoscandia. The actual length of the growing season reached 120 days on average, onset on 30 May and ending on 27 September (1981-2010). Shifts in the timing of the growing season and its mean prolongation by 18.5 days/62a are demonstrated for Murmansk Region (1951-2012). In this period, the onset of the growing season advanced by 7.1 days/62a, while the end was extended by 11.4 days/62a. The delay in the end of the growing season is similar to the entire Fennoscandian pattern but it has not been detected in the rest of Europe. The regional pattern of climatic regimes in Murmansk Region remained stable in comparison with earlier climatic maps (1971). However, the actual shifts in the timing of the growing season were more pronounced in colder (oceanic and mountainous) parts. Recent climatic trends could influence the retreat of the tundra zone and changes in the forest line. Losses of tundra biodiversity and enrichment of the northern taiga by southern species could be expected from present climatic trends.

  13. Climatic warming above the Arctic Circle: are there trends in timing and length of the thermal growing season in Murmansk Region (Russia) between 1951 and 2012?

    PubMed

    Blinova, Ilona; Chmielewski, Frank-Michael

    2015-06-01

    Anomalies in the timing of the thermal growing season have become obvious in the NE part of Fennoscandia since 2000. They are in accordance with climatic changes reported for Europe and Fennoscandia. The actual length of the growing season reached 120 days on average, onset on 30 May and ending on 27 September (1981-2010). Shifts in the timing of the growing season and its mean prolongation by 18.5 days/62a are demonstrated for Murmansk Region (1951-2012). In this period, the onset of the growing season advanced by 7.1 days/62a, while the end was extended by 11.4 days/62a. The delay in the end of the growing season is similar to the entire Fennoscandian pattern but it has not been detected in the rest of Europe. The regional pattern of climatic regimes in Murmansk Region remained stable in comparison with earlier climatic maps (1971). However, the actual shifts in the timing of the growing season were more pronounced in colder (oceanic and mountainous) parts. Recent climatic trends could influence the retreat of the tundra zone and changes in the forest line. Losses of tundra biodiversity and enrichment of the northern taiga by southern species could be expected from present climatic trends. PMID:25155187

  14. Verification of satellite radar remote sensing based estimates of boreal and subalpine growing seasons using an ecosystem process model and surface biophysical measurement network information

    NASA Technical Reports Server (NTRS)

    McDonald, K. C.; Kimball, J. S.; Zimmerman, R.

    2002-01-01

    We employ daily surface Radar backscatter data from the SeaWinds Ku-band Scatterometer onboard Quikscat to estimate landscape freeze-thaw state and associated length of the seasonal non-frozen period as a surrogate for determining the annual growing season across boreal and subalpine regions of North America for 2000 and 2001.

  15. Environmental effects of growing short-rotation woody crops on former agricultural lands

    SciTech Connect

    Tolbert, V.R.; Thornton, F.C.; Joslin, J.D.

    1997-10-01

    Field-scale studies in the Southeast have been addressing the environmental effects of converting agricultural lands to biomass crop production since 1994. Erosion, surface water quality and quantity and subsurface movement of water and nutrients from woody crops, switchgrass and agricultural crops are being compared. Nutrient cycling, soil physical changes and crop productivity are also being monitored at the three sites. Maximum sediment losses occurred in the spring and fall. Losses were greater from sweetgum planted without a cover crop than with a cover crop. Nutrient losses of N and P in runoff and subsurface water occurred primarily after spring fertilizer application.

  16. Leaf ontogeny dominates the seasonal exchange of volatile organic compounds (VOC) in a SRC-poplar plantation during an entire growing season

    NASA Astrophysics Data System (ADS)

    Brilli, Federico; Gioli, Beniamino; Fares, Silvano; Zenone, Terenzio; Zona, Donatella; Gielen, Bert; Loreto, Francesco; Janssens, Ivan; Ceulemans, Reinhart

    2015-04-01

    The declining cost of many renewable energy technologies and changes in the prices of fossil fuels have recently encouraged governments policies to subsidize the use of biomass as a sustainable source of energy. Deciduous poplars (Populus spp.) trees are often selected for biomass production in short rotation coppiced (SRC) for their high CO2 photosynthetic assimilation rates and their capacity to develop dense canopies with high values of leaf area index (LAI). So far, observations and projections of seasonal variations of many VOC fluxes has been limited to strong isoprenoids emitting evergreen ecosystems such tropical and Mediterranean forests as well as Citrus and oil palm plantation, all having constant values of LAI. We run a long-term field campaign where the exchange of VOC, together with CO2 and water vapor was monitored during an entire growing season (June - November, 2012) above a SRC-based poplar plantation. Our results confirmed that isoprene and methanol were the most abundant fluxes emitted, accounting for more than 90% of the total carbon released in form of VOC. However, Northern climates characterized by fresh summertime temperatures and recurring precipitations favored poplar growth while inhibiting the development of isoprene emission that resulted in only 0.7% of the net ecosystem carbon exchange (NEE). Besides, measurements of a multitude of VOC fluxes by PTR-TOF-MS showed bi-directional exchange of oxygenated-VOC (OVOC) such as: formaldehyde, acetaldehyde, acetone, isoprene oxidation products (iox, namely MVK, MAC and MEK) as well as ethanol and formic acid. The application of Self Organizing Maps to visualize the relationship between the full time-series of many VOC fluxes and the observed seasonal variations of environmental, physiological and structural parameters proved the most abundant isoprene ad methanol fluxes to occur mainly on the hottest days under mid-high light intensities when also NEE and evapotraspiration reached the highest

  17. Exposure to Atrazine and Selected Non-Persistent Pesticides among Corn Farmers during a Growing Season

    PubMed Central

    Bakke, Berit; De Roos, Anneclaire J.; Barr, Dana B.; Stewart, Patricia A.; Blair, Aaron; Freeman, Laura Beane; Lynch, Charles F.; Allen, Ruth H.; Alavanja, Michael C.R.; Vermeulen, Roel

    2011-01-01

    Objectives The aim was to develop quantitative estimates of farmers’ pesticide exposure to atrazine and to provide an overview of background levels of selected non-persistent pesticides among corn farmers in a longitudinal molecular epidemiologic study. Methods The study population consisted of 30 Agricultural Health Study farmers from Iowa and 10 nonfarming controls. Farmers completed daily and weekly diaries from March to November in 2002 and 2003 on pesticide use and other exposure determinants. Urine samples were collected at 10 timepoints relative to atrazine application and other farming activities. Pesticide exposure was assessed using urinary metabolites and diaries. Results The analytical limit of detection (LOD) ranged between 0.1–0.2 μg/l for all pesticide analytes except for isazaphos (1.5 μg/l) and diazinon (0.7 μg/l). Farmers had higher geometric mean urinary atrazine mercapturate (AZM) values than controls during planting (1.1 vs.

  18. The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem

    NASA Astrophysics Data System (ADS)

    Cassidy, A. E.; Christen, A.; Henry, G. H. R.

    2015-12-01

    Soil carbon stored in high-latitude permafrost landscapes is threatened by warming, and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, have increased in frequency and magnitude across the Fosheim Peninsula, Ellesmere Island, Canada. To determine the effects of retrogressive thaw slumps on net ecosystem exchange (NEE) of CO2 in high Arctic tundra, we used two eddy covariance (EC) tower systems to simultaneously and continuously measure CO2 fluxes from a disturbed site and the surrounding undisturbed tundra. During the 32-day measurement period in the 2014 growing season the undisturbed tundra was a small net sink (NEE = -0.12 g C m-2 d-1); however, the disturbed terrain of the retrogressive thaw slump was a net source (NEE = +0.39 g C m-2 d-1). Over the measurement period, the undisturbed tundra sequestered 3.84 g C m-2, while the disturbed tundra released 12.48 g C m-2. Before full leaf out in early July, the undisturbed tundra was a small source of CO2, but shifted to a sink for the remainder of the sampling season (July), whereas the disturbed tundra remained a source of CO2 throughout the season. A static chamber system was also used to measure fluxes in the footprints of the two towers, in both disturbed and undisturbed tundra, and fluxes were partitioned into ecosystem respiration (Re) and gross primary production (GPP). Average GPP and Re found in disturbed tundra were smaller (+0.41 μmol m-2 s-1 and +0.50 μmol m-2 s-1, respectively) than those found in undisturbed tundra (+1.21 μmol m-2 s-1 and +1.00 μmol m-2 s-1, respectively). Our measurements indicated clearly that the permafrost disturbance changed the high Arctic tundra system from a sink to a source for CO2 during the growing season.

  19. The effect of a permafrost disturbance on growing-season carbon-dioxide fluxes in a high Arctic tundra ecosystem

    NASA Astrophysics Data System (ADS)

    Cassidy, Alison E.; Christen, Andreas; Henry, Gregory H. R.

    2016-04-01

    Soil carbon stored in high-latitude permafrost landscapes is threatened by warming and could contribute significant amounts of carbon to the atmosphere and hydrosphere as permafrost thaws. Thermokarst and permafrost disturbances, especially active layer detachments and retrogressive thaw slumps, are present across the Fosheim Peninsula, Ellesmere Island, Canada. To determine the effects of retrogressive thaw slumps on net ecosystem exchange (NEE) of CO2 in high Arctic tundra, we used two eddy covariance (EC) tower systems to simultaneously and continuously measure CO2 fluxes from a disturbed site and the surrounding undisturbed tundra. During the 32-day measurement period in the 2014 growing season, the undisturbed tundra was a small net sink (NEE = -0.1 g C m-2 d-1); however, the disturbed terrain of the retrogressive thaw slump was a net source (NEE = +0.4 g C m-2 d-1). Over the measurement period, the undisturbed tundra sequestered 3.8 g C m-2, while the disturbed tundra released 12.5 g C m-2. Before full leaf-out in early July, the undisturbed tundra was a small source of CO2 but shifted to a sink for the remainder of the sampling season (July), whereas the disturbed tundra remained a source of CO2 throughout the season. A static chamber system was also used to measure daytime fluxes in the footprints of the two towers, in both disturbed and undisturbed tundra, and fluxes were partitioned into ecosystem respiration (Re) and gross primary production (GPP). Average GPP and Re found in disturbed tundra were smaller (+0.40 µmol m-2 s-1 and +0.55 µmol m-2 s-1, respectively) than those found in undisturbed tundra (+1.19 µmol m-2 s-1 and +1.04 µmol m-2 s-1, respectively). Our measurements indicated clearly that the permafrost disturbance changed the high Arctic tundra system from a sink to a source for CO2 during the majority of the growing season (late June and July).

  20. [Effects of nitrogen addition on available nitrogen content and acidification in cold-temperate coniferous forest soil in the growing season].

    PubMed

    Chen, Gao-Qi; Fu, Wa-Li; Luo, Ya-Chen; Gao, Wen-Long; Li, Sheng-Gong; Yang, Hao

    2014-12-01

    Based on a low-level and multi-form N addition control experiment, this study took cold-temperate coniferous forest in Daxing'an Ling as the research object. After long-term and continuous nitrogen addition in situ, the available nitrogen (NH4(+) -N & NO3(-) -N) contents and pH values of the soil (0-10 cm) were measured in the early growing season (May) and the peak growing season (August) in 2010, 2012 and 2013. The results showed that, the available nitrogen in the early and peak growing seasons was mainly NH4(+) -N which accounted for over 96% of the inorganic nitrogen content, while the content of NO3(-) -N was very low. With the time extension of nitrogen addition, the effects of nitrogen addition on the NH4(+) -N content in 0-10 cm soil were more obvious in the early growing season than that in the peak growing season, and the NH4(+) -N content was mainly affected by the type of nitrogen addition. On the contrary, the NO3(-) -N content in 0-10 cm soil was higher in the peak growing season than that in the early growing season. The effect of N input was obvious on NO3(-) -N content in both early and peak growing seasons, and low nitrogen treatment tended to promote the enrichment of NO3(-) -N. As time went on, the response of NH4(+) -N and NO3(-) -N content to N addition was changed from insignificant in the early stage to significant in the late stage. N addition had a significant impact on the pH value of the 0-10 cm soil in the early and peak growing seasons. The pH values of the soil with low nitrogen treatment and the soil in the peak growing season were relatively lower. With the extension of the nitrogen addition time, the response of pH value also turned from insignificant in the early stage to significant in the late stage. Because of the long-term and continuous nitrogen addition, the 0 - 10 cm soil in this cold-temperate coniferous forest was obviously acidified. PMID:25826942

  1. Growing Indian Fig Opuntia on selenium-laden agriculture drainage sediment under field conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growing alternative crops for saline and selenium (Se) impacted lands in arid regions, e.g., Western United States, depends upon the plant’s ability to tolerate the presence of high salts and boron (B). In this field study, we planted 2-month old cacti plants on 30 x 1m beds and evaluated the abilit...

  2. Metal contamination of soil and translocation in vegetables growing under industrial wastewater irrigated agricultural field of Vadodara, Gujarat, India.

    PubMed

    Tiwari, K K; Singh, N K; Patel, M P; Tiwari, M R; Rai, U N

    2011-09-01

    The present investigation was carried out to evaluate metals concentration in ten vegetable crops growing in mixed industrial effluent irrigated agricultural field near Vadodara, Gujarat, India. Differential accumulation and translocation of various metals in selected vegetables plant species was observed. A higher concentration of metals were found in order of Fe>Mn>Zn>Cd>Cu>Pb>Cr>As in soil irrigated with industrial effluent than soil irrigated with tube well water; however, the concentration of As, Cr and Pb found below detection limit in tube well water irrigated soil. Metal accumulation in root and top of vegetables varied significantly both in relations to metal concentration in the soil and the plant genotype. Among ten vegetable species studied five vegetable species, i.e. Spinach, Radish, Tomato, Chili and Cabbage growing in mixed industrial effluent irrigated agricultural field showed high accumulation and translocation of toxic metals (As, Cd, Cr, Pb and Ni) in their edible parts, thus, their cultivation are unsafe with respect to possible transfer in food chain and health hazards. However, it is suggested that vegetable crops restricting toxic metal in non-edible port may be recommended for cultivation in such metal contaminated agricultural field. PMID:21555153

  3. Utilisation of young and old soil carbon sources by microbial groups differ during the growing season and between experimental treatments in a long-term field experiment

    NASA Astrophysics Data System (ADS)

    Börjesson, Gunnar; Menichetti, Lorenzo; Thornton, Barry; Campbell, Colin; Kätterer, Thomas

    2014-05-01

    Soil organic matter (SOM)is the largest active carbon pool in the terrestrial environment. SOM is a key factor for soil fertility, but is also important for the sequestration of atmospheric CO2. In agricultural soils, management of plant residues and the use of organic fertilisers play important roles for maintaining SOM. Switching from C3 plants to C4 plants such as maize, enables a natural labelling in situ; when coupled with compound specific 13C isotope analysis of phospholipid fatty acids (PLFAs) it allows the proportion of new C (fixed after the switch added to soil from above- and belowground litter and root exudates) and the proportion of old C (fixed prior to the switch derived from turnover of organic matter) utilised by the soil microbial community to be determined. (new paragraph) A field experiment in Sweden, amended with different mineral and organic fertilisers since 1956, was grown with C3 plants, mainly cereals until 1999. From the year 2000 silage maize was grown every year. In 2012, soil from four replicate plots of five experimental treatments, N fertilised, N fertilised amended with straw and sewage sludge, and two controls (bare fallow and cropped unfertilised) were sampled three times, at the start, middle and end of the growing season. Phospholipid fatty acids (PLFAs) were extracted from all soil samples and analysed for concentrations and 13C content. (new paragraph) Total PLFA concentrations and also the PLFA/SOM ratios increased with SOM in the different treatments. Seasonal variation in total PLFA was small except for the most SOM-rich treatment (sewage sludge) where concentrations significantly decreased during the growing season indicating the depletion of a labile SOM pool. Weighted mean values of δ13C in PLFAs show that the plots fertilised with only calcium nitrate had the highest δ13C-values in PLFAs before (-20.24 o) and after the vegetation period (-20.37 o), due to a large input of 13C-enriched plant material. However, during

  4. Irrigated acreage in the Bear River Basin as of the 1975 growing season. [Idaho, Utah, and Wyoming

    NASA Technical Reports Server (NTRS)

    Ridd, M. K.; Jaynes, R. A.; Landgraf, K. F.; Clark, L. D., Jr. (Principal Investigator)

    1982-01-01

    The irrigated cropland in the Bear River Basin as of the 1975 growing season was inventoried from satellite imagery. LANDSAT color infrared images (scale 1:125,000) were examined for early, mid, and late summer dates, and acreage was estimated by use of township/section overlays. The total basin acreage was estimated to be 573,435 acres, with individual state totals as follows: Idaho 234,370 acres; Utah 265,505 acres; and Wyoming 73,560 acres. As anticipated, wetland areas intermingled among cropland appears to have produced an over-estimation of irrigated acreage. According to a 2% random sample of test sites evaluated by personnel from the Soil Conservation Service such basin-wide over-estimation is 7.5%; individual counties deviate significantly from the basin-wide figure, depending on the relative amount of wetland areas intermingled with cropland.

  5. Contribution of grazing to soil atmosphere CH4 exchange during the growing season in a continental steppe

    NASA Astrophysics Data System (ADS)

    Tang, Shiming; Wang, Chengjie; Wilkes, Andreas; Zhou, Pei; Jiang, Yuanyuan; Han, Guodong; Zhao, Mengli; Huang, Ding; Schönbach, Philipp

    2013-03-01

    Degradation of steppes induced by overgrazing may affect the uptake of atmospheric methane (CH4) by soil sinks. However, uncertainty is associated with the very limited knowledge of gas fluxes in rapidly degrading steppe. In this study, we investigated the effects of grazing on CH4 uptake during the growing season in three types of steppe (meadow steppe, typical steppe and desert steppe and) in Inner Mongolia, China, to quantify and compare CH4 uptake in steppe ecosystems under different grazing management conditions. The CH4 fluxes were measured using an automatic cavity ring-down spectrophotometer at three steppe locations that differed primarily in grazing intensity. The results indicated that steppe soils were CH4 sinks throughout the growing season. CH4 uptake at all sites averaged 7.98 kg CH4-C ha-1 yr-1 (ranging from 1.53 to 18.74 kg CH4-C ha-1 yr-1), of which approximately 43.8% occurred in the desert steppe. CH4 uptake in the desert steppe increased 20.4% and 51.2% compared with the typical steppe and meadow steppe, respectively. Light grazing (LG) of steppe did not significantly change CH4 uptake compared with un-grazed (UG) steppe, but moderate and heavy grazing (MG, HG) reduced CH4 uptake significantly (by 6.8-37.9%, P < 0.05). These findings imply that reducing the grazing pressure on steppe would help increase the atmospheric CH4 sinks in steppe soils. Our results suggest that HG exerts a considerable negative impact on CH4 uptake in a continental steppe. Further studies involving year-round, intensive measurements of CH4 uptake are needed.

  6. Downscaling 250-m MODIS growing season NDVI based on multiple-date landsat images and data mining approaches

    USGS Publications Warehouse

    Gu, Yingxin; Wylie, Bruce K.

    2015-01-01

    The satellite-derived growing season time-integrated Normalized Difference Vegetation Index (GSN) has been used as a proxy for vegetation biomass productivity. The 250-m GSN data estimated from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors have been used for terrestrial ecosystem modeling and monitoring. High temporal resolution with a wide range of wavelengths make the MODIS land surface products robust and reliable. The long-term 30-m Landsat data provide spatial detailed information for characterizing human-scale processes and have been used for land cover and land change studies. The main goal of this study is to combine 250-m MODIS GSN and 30-m Landsat observations to generate a quality-improved high spatial resolution (30-m) GSN database. A rule-based piecewise regression GSN model based on MODIS and Landsat data was developed. Results show a strong correlation between predicted GSN and actual GSN (r = 0.97, average error = 0.026). The most important Landsat variables in the GSN model are Normalized Difference Vegetation Indices (NDVIs) in May and August. The derived MODIS-Landsat-based 30-m GSN map provides biophysical information for moderate-scale ecological features. This multiple sensor study retains the detailed seasonal dynamic information captured by MODIS and leverages the high-resolution information from Landsat, which will be useful for regional ecosystem studies.

  7. Migrant farmworkers' housing conditions across an agricultural season in North Carolina

    PubMed Central

    Vallejos, Quirina M.; Quandt, Sara A.; Grzywacz, Joseph G.; Isom, Scott; Chen, Haiying; Galván, Leonardo; Whalley, Lara; Chatterjee, Arjun B.; Arcury, Thomas A.

    2011-01-01

    Background Several studies have documented poor housing conditions for farmworkers but none has focused on migrant farmworker housing, which is often provided as a condition of employment. Farmworker housing quality is regulated, but little documentation exists of compliance with regulations. Methods A 2007 survey of 43 randomly selected farmworker camps and a 2008 survey of 27 camps randomly selected from the 2007 sample documented housing conditions via interviewer administered questionnaire and housing checklist. Results Substandard conditions are common in migrant housing. All camps had at least one exterior housing problem; 93% had at least one interior problem. Housing conditions worsen across the agricultural season. Characteristics including no residents with H2A visa and 11 or more residents are associated with poorer conditions. Conclusions Housing standards are not adequately enforced. An increase in post-occupancy inspections and targeting camps with characteristics that place them at increased risk for substandard conditions are recommended. PMID:21360725

  8. Application of Satellite Data for Early Season Assessment of Fallowed Agricultural Lands for Drought Impact Reporting

    NASA Astrophysics Data System (ADS)

    Rosevelt, C.; Melton, F. S.; Johnson, L.; Verdin, J. P.; Thenkabail, P. S.; mueller, R.; Zakzeski, A.; Jones, J.

    2013-12-01

    Rapid assessment of drought impacts can aid water managers in assessing mitigation options, and guide decision making with respect to requests for local water transfers, county drought disaster designations, or state emergency proclamations. Satellite remote sensing offers an efficient way to provide quantitative assessments of drought impacts on agricultural production and land fallowing associated with reductions in water supply. A key advantage of satellite-based assessments is that they can provide a measure of land fallowing that is consistent across both space and time. Here we describe an approach for monthly mapping of land fallowing developed as part of a joint effort by USGS, USDA, and NASA to provide timely assessments of land fallowing during drought events. This effort has used the Central Valley of California as a pilot region for development and testing of an operational approach. To provide quantitative measures of fallowed land from satellite data early in the season, we developed a decision tree algorithm and applied it to timeseries of normalized difference vegetation index (NDVI) data from Landsat TM, ETM+, and MODIS. Our effort has been focused on development of leading indicators of drought impacts in the March - June timeframe based on measures of crop development patterns relative to a reference period with average or above average rainfall. This capability complements ongoing work by USDA to produce and publicly release within-season estimates of fallowed acreage from the USDA Cropland Data Layer. To assess the accuracy of the algorithms, monthly ground validation surveys were conducted along transects across the Central Valley at more than 200 fields per month from March - June, 2013. Here we present the algorithm for mapping fallowed acreage early in the season along with results from the accuracy assessment, and discuss potential applications to other regions.

  9. Proposal of a growth chamber for growing Super-Dwarf Rice in Space Agriculture

    NASA Astrophysics Data System (ADS)

    Hirai, Hiroaki; Kitaya, Yoshiaki; Tsukamoto, Koya; Yamashita, Youichirou; Hirai, Takehiro

    Space agriculture needs to be considered to supply food for space crew who stay in space over an extended time period. So far crops such as wheat, onion, oat, pea and lettuce grew to explore the possibility of space agriculture. Although rice is a staple food for most of the world, research on rice cultivation in space has not been done much. Rice grains are nutrient-rich with carbohydrate, protein and dietary fiber. Moreover, rice is a high yield crop and harvested grains have a long shelf life. However, the plant height of standard rice cultivars is relatively long, requiring much space. In addition, rice plants require higher light intensities for greater yield. For these reasons, it is difficult to establish facilities for rice culture in a limited space with a low cost. We propose to employee a super-dwarf cultivar and a small growth chamber with a new type of LEDs. The super-dwarf rice is a short-grain japonica variety and the plant height is approximately 20 cm that is one-fifth as tall as standard cultivars. The LED light used as a light source for this study can provide full spectrum of 380 nm to 750 nm. Air temperature and humidity were controlled by a Peltier device equipped in the chamber. The characteristics of the new type of LEDs and other equipments of the chamber and the ground based performance of super-dwarf rice plants grown in the chamber will be reported.

  10. Impacts of Prognostic Phenology and Agriculture on the Seasonal Cycle of Carbon Fluxes

    NASA Astrophysics Data System (ADS)

    Haynes, K. D.; Baker, I. T.; Denning, A.; Stockli, R.; Lokupitiya, E. Y.

    2011-12-01

    Since terrestrial carbon fluxes cannot be measured directly on regional and global scales, land surface models are an important tool in improving estimates of carbon sources and sinks. One common limitation in biosphere models is requiring the use of remotely sensed data to represent vegetation phenology; however, prognostic phenology models are being developed to predict the phonological timing and leaf state of both natural vegetation and crops (Stockli et al., 2008; Lokupitiya et al., 2009; Stockli et al., 2011). Simulating phenology rather than relying on data products removes the uncertainty due to satellite retrievals, allows the short yet highly productive growing season of crops to be more accurately simulated, and enables predictive capabilities. The Simple Biosphere Model (SiB) has been modified to include prognostic phenology for twenty different plant functional types, including maize, soybean and wheat. Predicting the phenology will alter carbon fluxes regionally and globally on diurnal to seasonal timescales, and this study will discuss the impact of prognostic phenology on the resulting simulated net ecosystem exchange of carbon dioxide.

  11. Pesticide residues in some herbs growing in agricultural areas in Poland.

    PubMed

    Malinowska, Elżbieta; Jankowski, Kazimierz

    2015-12-01

    The aim of this paper was to assess residue content of plant protection products in selected herbs: Achillea millefolium L., Cichorium intybus L., Equisetum arvense L., Polygonum persicaria L., Plantago lanceolata L., and Plantago major L. The study comprises herbs growing in their natural habitat, 1 and 10 m away from crop fields. The herbs, 30 plants of each species, were sampled during the flowering stage between 1 and 20 July 2014. Pesticide residue content was measured with the QuECHERS method in the dry matter of leaves, stalks, and inflorescence, all mixed together. Out of six herb species growing close to wheat and maize fields, pesticide residues were found in three species: A. millefolium L., E. arvense L., and P. lanceolata L. Most plants containing the residues grew 1 m away from the wheat field. Two active substances of fungicides were found: diphenylamine and tebuconazole, and one active substance of insecticides: chlorpyrifos-ethyl. Those substances are illegal to use on herbal plants. Samples of E. arvense L. and P. lanceolata L. contained two active substances each, which constituted 10% of all samples, while A. millefolium L. contained one substance, which is 6.6% of all samples. PMID:26612566

  12. DOMESTIC AGRICULTURAL MIGRANTS IN THE UNITED STATES, COUNTIES IN WHICH AN ESTIMATED 100 OR MORE SEASONAL AGRICULTURAL WORKERS MIGRATED INTO THE AREA OF WORK DURING THE PEAK SEASON IN 1965.

    ERIC Educational Resources Information Center

    Bureau of Employment Security (DOL), Washington, DC.

    THE NUMBER OF SEASONAL DOMESTIC AGRICULTURAL MIGRANTS IN EACH COUNTY OF THE UNITED STATES IS PRESENTED GRAPHICALLY ON THIS 26 BY 40 INCH MAP. PUBLIC HEALTH AND OTHER SERVICE AGENCIES MAY USE IT AND ACCOMPANYING TABLES TO PLAN PROGRAM ADJUSTMENTS NECESSITATED BY THE WORKER INFLUX. THE DATA ARE CONFINED TO DOMESTIC WORKERS AND THEIR ACCOMPANYING…

  13. Does increased mid-growing season absorbed PAR compensate for the loss due to longer snow cover duration in a subarctic permafrost mire?

    NASA Astrophysics Data System (ADS)

    Bosio, J.; Christensen, T. R.; Johansson, M.

    2012-12-01

    This study was initiated to analyse the effect of snow cover on photosynthesis and plant growth in subarctic mires underlain by permafrost. Due to their narrow environmental window these raised bogs, called palsa mires, are highly sensitive to climatic changes. In Fennoscandia palsa mires are currently subjected to climate related thawing and shift in vegetational and hydrological patterns. Yet, we know little of how these subarctic permafrost mires react and feed back to such changes. By using snow fences to hinder snow drift the amount of accumulated snow was increased in a snow manipulation experiment on a subarctic permafrost mire in northern Sweden. The increase in accumulated snow prolongs the duration of the snow cover in spring, causing a delay in the onset, as well as an overall shortening of the growing season. By measuring incoming and reflected photosynthetic active radiation (PAR) we wanted to address the question whether this shortening of the growing season affected the absorbed PAR, and possibly the total gross primary production (GPP) over the season. The reflected PAR was measured at twelve plots where six of the plots experienced increased snow accumulation (treatment), and remaining six plots were untreated (control). Minikin QT sensors and dataloggers logged incoming and reflected PAR hourly throughout the growing seasons of 2011 and 2012. The increased accumulation of snow resulted in a 18 and 3 days delay in the growing season start in treatment plots for 2011 and 2012 respectively. The end of the growing season was not affected by the snow manipulation; hence the overall length of the growing season was shortened by 18 and 3 days in treatment plots in relation to the control plots in 2011 and 2012 respectively. Preliminary results show that the loss in absorbed PAR due to the shortening of the growing season in the treatment plots is well compensated for by a significant increase in absorption of PAR throughout the whole growing season. This

  14. Growing Lemna minor in agricultural wastewater and converting the duckweed biomass to ethanol.

    PubMed

    Ge, Xumeng; Zhang, Ningning; Phillips, Gregory C; Xu, Jianfeng

    2012-11-01

    Duckweed (Lemna minor) was grown in swine lagoon wastewater and Schenk & Hildebrandt medium with a growth rate of 3.5 and 14.1 g m(-2)day(-1) (dry basis), respectively detected. The rapid accumulation of starch in duckweed biomass (10-36%, w/w) was triggered by nutrient starvation or growing in dark with addition of glucose. The harvested duckweed biomass (from culture in wastewater) contained 20.3% (w/w) total glucan, 32.3% (w/w) proteins, trace hemicellulose and undetectable lignin. Without prior thermal-chemical pretreatment, up to 96.2% (w/w) of glucose could be enzymatically released from both the cellulose and starch fractions of duckweed biomass. The enzymatic hydrolysates could be efficiently fermented by two yeast strains (self-flocculating yeast SPSC01 and conventional yeast ATCC 24859) with a high ethanol yield of 0.485 g g(-1) (glucose). PMID:22985823

  15. Temperature drives inter-annual variability of growing season CO2 and CH4 fluxes of Siberian lowland tundra

    NASA Astrophysics Data System (ADS)

    Kutzbach, Lars; Wille, Christian; Runkle, Benjamin; Schreiber, Peter; Sachs, Torsten; Langer, Moritz; Boike, Julia; Pfeiffer, Eva-Maria

    2015-04-01

    Due to the logistic and technical difficulties associated with experimental work in high latitudes, long-term measurements of CO2 and CH4 fluxes from arctic ecosystems are still rare, and published trace gas balances often rely on measurements from one or few growing seasons. The inter-annual variability of environmental conditions such as temperature, precipitation, snow cover, and timing of snow melt can be high in the Arctic, especially for regions which are influenced by both continental and maritime climates, such as the Siberian arctic lowlands. For these ecosystems, we must also expect a great inter-annual variability in the balance of trace gases. Multi-annual data sets are needed to investigate this variability and its drivers. Here we present multi-annual late summer CO2 and CH4 flux data from the Lena River Delta in the Siberian Arctic (72° N, 126° E). The study site Samoylov Island is characterized by polygonal lowland tundra, a vegetation dominated by mosses and sedges, a soil complex of Glacic, Turbic and Histic Cryosols, and an active layer depth of on average 0.5 m. Seasonal flux measurements were carried out with the eddy covariance technique during the 13-year period 2002 - 2014. Within this period, CO2 flux data overlaps during 37 days (20 July - 25 August) for 12 years, and CH4 flux data overlaps during 25 days (28 July - 21 August) for 9 years. Cumulative net ecosystem CO2 exchange (NEE) during the late summer overlap period is fairly consistent for 9 out of 12 years with a CO2 uptake of 1.9 ± 0.1 mol m-2. Three years show a clearly smaller uptake of

  16. Climate change, growing season water deficit and vegetation activity along the north-south transect of Eastern China from 1982 through 2006

    NASA Astrophysics Data System (ADS)

    Sun, P.; Yu, Z.; Liu, S.; Wei, X.; Wang, J.; Zegre, N.

    2012-05-01

    Considerable work has been done to examine the relationship between environmental constraints and vegetation activities represented by the remote sensing-based Normalized Difference Vegetation Index (NDVI). However, the relationships along either environmental or vegetation type gradients are rarely examined. The aim of this paper was to identify the vegetation types that are potentially susceptible to climate change through examining the interaction between vegetation activity and water deficit. We selected 12 major vegetation types along the north-south transect of Eastern China (NSTEC), examined their time trends from 1982 to 2006 with respect to climate change, vegetation activity and water deficit. The results showed that all vegetation types experienced warming during the study period, and the majority of them experienced precipitation decline. Warming and growing season water deficit exert counteracting controls on vegetation activity. Our study found insignificant greening trends in the northernmost cold temperate coniferous forest (CTCF), three temperate herbaceous types including the meadow steppe (TMS), grass steppe (TGS) and grassland (TG), where the growing season warming exerted more than offset effect on vegetation activity (phenology) than growing season water deficit. For the three temperate forest including the coniferous (TCF), mixed (TMF) and deciduous-broadleaved (TDBF), growing season water deficit was the main constraint on vegetation activity. Differently, the growing season browning in subtropical or tropical forests of coniferous (STCF), deciduous-broadleaved (SDBF) and evergreen-broadleaved (SEBF) and subtropical grasslands (STG) were likely attributed to decline in sunshine duration due to increased summer cloudiness. Poor water status in TDS, TG, TMS and severe drought in TGS have been identified by using growing season water deficit index (GWDI), suggested these ecosystems were subjected to severe progressing drought that may create

  17. Migrant and Seasonal Workers in Michigan's Agriculture: A Study of Their Contributions, Characteristics, Needs, and Services. Research Report No. 1.

    ERIC Educational Resources Information Center

    Rochin, Refugio I.; Santiago, Anne M.; Dickey, Karla S.

    This study examines the characteristics and needs of Michigan's migrant and seasonal farmworkers. The study was based on census data, state agency records, and a statewide survey of service providers. Results indicate that neither mechanization nor other structural changes in Michigan's agricultural economy have diminished the industry's…

  18. 1961 ACTIVITIES IN CALIFORNIA DIRECTED TOWARD THE IMPROVEMENT OF HEALTH AMONG DOMESTIC SEASONAL AGRICULTURAL WORKERS AND THEIR FAMILIES.

    ERIC Educational Resources Information Center

    1961

    A PROGRAM INSTITUTED IN 1961 TO IMPROVE THE HEALTH OF DOMESTIC SEASONAL AGRICULTURAL WORKERS IN CALIFORNIA AND THEIR FAMILIES WAS GIVEN. IT SOUGHT TO HELP LOCAL HEALTH AGENCIES BY PROVIDING--TECHNICAL ASSISTANCE TO COUNTIES TRYING TO DEVELOP FACILITIES AND SERVICES, EARLY DEVELOPMENT OF POLICIES AND PROCEDURES FOR USE OF STATE FUNDS BY LOCAL…

  19. 78 FR 32460 - Comment Request for Information Collection for ETA Form 232, Domestic Agricultural In-Season Wage...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-30

    ... Federal or State minimum wage, whichever is higher.'' The collection is also required by regulations for... legal federal or State minimum wage rate, whichever is highest unless special procedures apply to the... Agricultural In-Season Wage Report and ETA Form 232-A, Wage Survey Interview Record, Extension with...

  20. Leaching techniques for saline wastes composts used as growing media in organic agriculture: assessment and modelling.

    PubMed

    Illera-Vives, Marta; López-Mosquera, María Elvira; Salas-Sanjuan, María Del Carmen; López-Fabal, Adolfo

    2015-05-01

    The purpose of this work was to examine solute release by the effect of leaching of a saline compost with two main objectives: (1) to identify the most efficient method for this purpose, in order to minimize the environmental impact of this process in terms of water consumption and (2) to study the composition of the leachates to manage them properly and avoid possible contamination. A laboratory method involving column leaching with distilled water (CL) and two field methods involving saturation leaching (SL) and drip leaching (DL) were compared to this end. In order to more accurately assess nutrient release and compare the three leaching techniques, the cumulative amounts of ions leached were processed by using an exponential growth model. All target ions fitted properly, and so did the curve for the ions as a whole. Salts were removed mainly by effect of the leaching of major ions in the substrate (Na(+), Cl(-), inorganic N, SO4 (2-) and K(+)). SL and CL proved similarly efficient and reduced the salt content of the substrate to an electrical conductivity below 2 dS m(-1) in the saturation extract, which is the optimum level for nursery crops. By contrast, the DL method provided poor results: salt contents were reduced to an electrical conductivity of only 8 dS m(-1) in the saturation extract, so the resulting substrate can only be useful to grow highly salt-tolerant crops. PMID:25471718

  1. Importance of recent shifts in soil thermal dynamics on growing season length, productivity, and carbon sequestration in terrestrial high-latitude ecosystems

    USGS Publications Warehouse

    Euskirchen, E.S.; McGuire, A.D.; Kicklighter, D.W.; Zhuang, Q.; Clein, J.S.; Dargaville, R.J.; Dye, D.G.; Kimball, J.S.; McDonald, K.C.; Melillo, J.M.; Romanovsky, V.E.; Smith, N.V.

    2006-01-01

    In terrestrial high-latitude regions, observations indicate recent changes in snow cover, permafrost, and soil freeze-thaw transitions due to climate change. These modifications may result in temporal shifts in the growing season and the associated rates of terrestrial productivity. Changes in productivity will influence the ability of these ecosystems to sequester atmospheric CO2. We use the terrestrial ecosystem model (TEM), which simulates the soil thermal regime, in addition to terrestrial carbon (C), nitrogen and water dynamics, to explore these issues over the years 1960-2100 in extratropical regions (30-90??N). Our model simulations show decreases in snow cover and permafrost stability from 1960 to 2100. Decreases in snow cover agree well with National Oceanic and Atmospheric Administration satellite observations collected between the years 1972 and 2000, with Pearson rank correlation coefficients between 0.58 and 0.65. Model analyses also indicate a trend towards an earlier thaw date of frozen soils and the onset of the growing season in the spring by approximately 2-4 days from 1988 to 2000. Between 1988 and 2000, satellite records yield a slightly stronger trend in thaw and the onset of the growing season, averaging between 5 and 8 days earlier. In both, the TEM simulations and satellite records, trends in day of freeze in the autumn are weaker, such that overall increases in growing season length are due primarily to earlier thaw. Although regions with the longest snow cover duration displayed the greatest increase in growing season length, these regions maintained smaller increases in productivity and heterotrophic respiration than those regions with shorter duration of snow cover and less of an increase in growing season length. Concurrent with increases in growing season length, we found a reduction in soil C and increases in vegetation C, with greatest losses of soil C occurring in those areas with more vegetation, but simulations also suggest that

  2. Denitrification in Agriculturally Impacted Streams: Seasonal Changes in Structure and Function of the Bacterial Community

    PubMed Central

    Manis, Erin; Royer, Todd V.; Johnson, Laura T.; Leff, Laura G.

    2014-01-01

    Denitrifiers remove fixed nitrogen from aquatic environments and hydrologic conditions are one potential driver of denitrification rate and denitrifier community composition. In this study, two agriculturally impacted streams in the Sugar Creek watershed in Indiana, USA with different hydrologic regimes were examined; one stream is seasonally ephemeral because of its source (tile drainage), whereas the other stream has permanent flow. Additionally, a simulated flooding experiment was performed on the riparian benches of the ephemeral stream during a dry period. Denitrification activity was assayed using the chloramphenicol amended acetylene block method and bacterial communities were examined based on quantitative PCR and terminal restriction length polymorphisms of the nitrous oxide reductase (nosZ) and 16S rRNA genes. In the stream channel, hydrology had a substantial impact on denitrification rates, likely by significantly lowering water potential in sediments. Clear patterns in denitrification rates were observed among pre-drying, dry, and post-drying dates; however, a less clear scenario was apparent when analyzing bacterial community structure suggesting that denitrifier community structure and denitrification rate were not strongly coupled. This implies that the nature of the response to short-term hydrologic changes was physiological rather than increases in abundance of denitrifiers or changes in composition of the denitrifier community. Flooding of riparian bench soils had a short-term, transient effect on denitrification rate. Our results imply that brief flooding of riparian zones is unlikely to contribute substantially to removal of nitrate (NO3-) and that seasonal drying of stream channels has a negative impact on NO3- removal, particularly because of the time lag required for denitrification to rebound. This time lag is presumably attributable to the time required for the denitrifiers to respond physiologically rather than a change in abundance or

  3. Development of the Seasonal Migrant Agricultural Worker Stress Scale in Sanliurfa, Southeast Turkey.

    PubMed

    Simsek, Zeynep; Ersin, Fatma; Kirmizitoprak, Evin

    2016-01-01

    Stress is one of the main causes of health problems, especially mental disorders. These health problems cause a significant amount of ability loss and increase cost. It is estimated that by 2020, mental disorders will constitute 15% of the total disease burden, and depression will rank second only after ischemic heart disease. Environmental experiences are paramount in increasing the liability of mental disorders in those who constantly face sustained high levels of stress. The objective of this study was to develop a stress scale for seasonal migrant agricultural workers aged 18 years and older. The sample consisted of 270 randomly selected seasonal migrant agricultural workers. The average age of the participants was 33.1 ± 14, and 50.7% were male. The Cronbach alpha coefficient and test-retest methods were used for reliability analyses. Although the factor analysis was performed for the structure validity of the scale, the Kaiser-Meyer-Olkin coefficient and Bartlett test were used to determine the convenience of the data for the factor analysis. In the reliability analyses, the Cronbach alpha coefficient of internal consistency was calculated as .96, and the test-retest reliability coefficient was .81. In the exploratory factor analysis for validity of the scale, four factors were obtained, and the factors represented workplace physical conditions (25.7% of the total variance), workplace psychosocial and economic factors (19.3% of the total variance), workplace health problems (15.2% of the total variance), and school problems (10.1% of the total variance). The four factors explained 70.3% of the total variance. As a result of the expert opinions and analyses, a stress scale with 48 items was developed. The highest score to be obtained from the scale was 144, and the lowest score was 0. The increase in the score indicates the increase in the stress levels. The findings show that the scale is a valid and reliable assessment instrument that can be used in

  4. The growing season water balance and controls on evapotranspiration in wetland reclamation test cells Fort McMurray, Alberta

    NASA Astrophysics Data System (ADS)

    Faubert, Jean-Pascal R.

    In the oil sands mining region near Fort McMurray, Alberta, efforts to establish specific wetland reclamation techniques are underway. During the 2010 growing season, the water balance of 12 plots (cells) of different soil and vegetation treatments were studied with emphasis on understanding the controls on evapotranspiration (ET) and the effects of construction techniques. Cell hydrologic behaviour was distinct from natural wetlands due to frequent artificial irrigation. ET ranged from ˜0 6 mm day-1 to ˜8.2 mm day-1 with a mean of ˜3.2 mm day-1 and variation among the cells was attributed to the construction techniques used, specifically placement period and soil depth. ET was weakly correlated to individual environmental variables; however, multivariate statistical models revealed complex interactions among environmental variables that acted to control ET. Cumulative water balances indicated certain construction techniques produced ET rates comparable to natural wetlands, which may be an important factor in improving the long-term sustainability of reclaimed wetlands.

  5. Wet and Dry Atmospheric Depositions of Inorganic Nitrogen during Plant Growing Season in the Coastal Zone of Yellow River Delta

    PubMed Central

    Li, Yunzhao; Du, Siyao; Han, Guangxuan; Xing, Qinghui; Wu, Huifeng; Wang, Guangmei

    2014-01-01

    The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD) using automatic sampling equipment. The results showed that SO42− and Na+ were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m−2, in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3−–N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4+–N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3−–N and NH4+–N was ~31.38% and ~20.50% for the contents of NO3−–N and NH4+–N in 0–10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD. PMID:24977238

  6. Positive effects of night warming on physiology of coniferous trees in late growing season: Leaf and root

    NASA Astrophysics Data System (ADS)

    Tang, Bo; Yin, Chunying; Wang, Yujie; Sun, Yuyu; Liu, Qing

    2016-05-01

    Previous studies about the effects of experimental warming on tree species have focused primarily on response of morphology and physiology in leaf and biomass allocation in the growing season, and a few studies considered the importance of roots. Based on the available evidence, it is unclear whether photosynthesis rate is enhanced by night warming in late autumn an issue that deserves further investigation. Thus, we exposed two coniferous species, Picea asperata and Abies faxoniana, to night warming continued throughout the year to investigate morphological and physiological responses of roots and leaves in the autumn. The results showed that night warming caused significant increases in net influxes of NH4+ and NO3- in P. asperata seedlings corresponding well with net H+ efflux and net influx of O2. Meanwhile, night warming had a positive effect on foliar gas exchange such as net photosynthesis rate, apparent quantum efficiency, dark respiration rate and maximum quantum efficiency of PS II, and nitrate reductase activity of roots. Additionally, root morphology such as total roots length, surface area, specific root area and specific root length was also stimulated by night warming. In contrast, night warming decreased concentrations of non-structural carbohydrate in leaves and roots of both species in autumn. The present study demonstrates that night warming would enhance late autumn leaf photosynthetic rate, and increase N uptake capacity of roots.

  7. Wet and dry atmospheric depositions of inorganic nitrogen during plant growing season in the coastal zone of Yellow River Delta.

    PubMed

    Yu, Junbao; Ning, Kai; Li, Yunzhao; Du, Siyao; Han, Guangxuan; Xing, Qinghui; Wu, Huifeng; Wang, Guangmei; Gao, Yongjun

    2014-01-01

    The ecological problems caused by dry and wet deposition of atmospheric nitrogen have been widespread concern in the world. In this study, wet and dry atmospheric depositions were monitored in plant growing season in the coastal zone of the Yellow River Delta (YRD) using automatic sampling equipment. The results showed that SO4 (2-) and Na(+) were the predominant anion and cation, respectively, in both wet and dry atmospheric depositions. The total atmospheric nitrogen deposition was ~2264.24 mg m(-2), in which dry atmospheric nitrogen deposition was about 32.02%. The highest values of dry and wet atmospheric nitrogen deposition appeared in May and August, respectively. In the studied area, NO3 (-)-N was the main nitrogen form in dry deposition, while the predominant nitrogen in wet atmospheric deposition was NH4 (+)-N with ~56.51% of total wet atmospheric nitrogen deposition. The average monthly attribution rate of atmospheric deposition of NO3 (-)-N and NH4 (+)-N was ~31.38% and ~20.50% for the contents of NO3 (-)-N and NH4 (+)-N in 0-10 cm soil layer, respectively, suggested that the atmospheric nitrogen was one of main sources for soil nitrogen in coastal zone of the YRD. PMID:24977238

  8. Wavelength shifts in fluorescence maxima of stressed and non-stressed Norway spruce needles over the growing season

    NASA Technical Reports Server (NTRS)

    Banninger, Cliff; Chappelle, E.

    1991-01-01

    Laboratory fluorescence measurements of first and third year metal stressed and non stressed Norway spruce needles collected in May, Jul. Sep. and Nov. display significant wavelength shifts in the intensity maxima in the blue, green, red, and near infrared spectral regions, with the largest shifts occurring in the blue spectral region for both first and third year needles from Nov. Smaller, but the otherwise significant shifts also take place in the blue spectral region for first year needles from Sep. in the red spectral region for third year neddles from May, Jul. and Sep. and in the near infrared spectral region for first and third year needles from Jul. and Sep. Wavelength shifts in needle fluorescence maxima over the growing season are greatest in the blue and to a lesser extent, greenspectral regions from Sep. to Nov. but are also significant in the red and near infrared spectral regions from Jul. to Sep. and Sep. to Nov., and in the near infrared spectral region also from May to Jul.

  9. Rate of Nitrogen Application during the Growing Season Alters Response of Container-Grown Rhododendron and Azalea to Foliar Urea in Autumn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One-year-old liners of rhododendron (Rhododendron ‘H-1 P.J.M’) and azalea (Rhododendron ‘Cannon’s Double’) grown at different N fertilization rates were used to assess the influence of foliar urea application in the autumn and soil nitrogen (N) applications during the growing season on N storage, N ...

  10. The value of seasonal forecasting and crop mix adaptation to climate variability for agriculture under climate change

    NASA Astrophysics Data System (ADS)

    Choi, H. S.; Schneider, U.; Schmid, E.; Held, H.

    2012-04-01

    Changes to climate variability and frequency of extreme weather events are expected to impose damages to the agricultural sector. Seasonal forecasting and long range prediction skills have received attention as an option to adapt to climate change because seasonal climate and yield predictions could improve farmers' management decisions. The value of seasonal forecasting skill is assessed with a crop mix adaptation option in Spain where drought conditions are prevalent. Yield impacts of climate are simulated for six crops (wheat, barely, cotton, potato, corn and rice) with the EPIC (Environmental Policy Integrated Climate) model. Daily weather data over the period 1961 to 1990 are used and are generated by the regional climate model REMO as reference period for climate projection. Climate information and its consequent yield variability information are given to the stochastic agricultural sector model to calculate the value of climate information in the agricultural market. Expected consumers' market surplus and producers' revenue is compared with and without employing climate forecast information. We find that seasonal forecasting benefits not only consumers but also producers if the latter adopt a strategic crop mix. This mix differs from historical crop mixes by having higher shares of crops which fare relatively well under climate change. The corresponding value of information is highly sensitive to farmers' crop mix choices.

  11. N2O and CH4 emissions from a Chinese wheat-rice cropping system under different tillage practices during the wheat-growing season

    NASA Astrophysics Data System (ADS)

    Zhang, Y.

    2015-12-01

    The annual wheat (Triticum aestivum L.)-rice (Oryza sativa L.) cropping system is the most important cereal production system in the Yangtze River Valley of China, in which various tillage systems are currently implemented during the wheat-growing season. The emissions of nitrous oxide (N2O) and methane (CH4) from the different tillage systems in this system remain unclear. We conducted a 3-year field experiment in a wheat-rice cropping system in a silt clay loam soil to investigate the effects of the type of tillage employed during the wheat-growing season (no-tillage (NT), reduced tillage (RT) or conventional tillage (CT)) on the emissions of N2O and CH4 using the static chamber method over three annual rotation cycles from the 2008 wheat season to the 2011 rice season. The results revealed that the adoption of an NT system during the wheat-growing season significantly increased CH4 emissions during both the wheat-growing season and the following rice-growing season. Over the three annual rotation cycles studied, the annual N2O emissions from the NT (2.24 kg N2O-N ha-1) and CT (2.01 kg N2O-N ha-1) treatments were similar to each other and significantly higher than those from the RT treatment (1.73 kg N2O-N ha-1); the annual CH4 emissions were significantly higher from the NT (100.1 kg CH4-C ha-1) than the CT (83.7 kg CH4-C ha-1) and RT (73.9 kg CH4-C ha-1) systems. The overall results regarding the net global warming potential associated with annual N2O and CH4 emissions indicate that the conversion of conventional tillage to no-tillage systems during the wheat-growing season would intensify the radiative forcing in wheat-rice cropping systems in China.

  12. Phenology Shifts at Start vs. End of Growing Season in Temperate Vegetation Over the Northern Hemisphere for the Period 1982-2008

    NASA Technical Reports Server (NTRS)

    Jeong, Su-Jong; Ho, Chang-Hoi; Gim, Hyeon-Ju; Brown, Molley E.

    2011-01-01

    Changes in vegetative growing seasons are dominant indicators of the dynamic response of ecosystems to climate change. Therefore, knowledge of growing seasons over the past decades is essential to predict ecosystem changes. In this study, the long-term changes in the growing seasons of temperate vegetation over the Northern Hemisphere were examined by analyzing satellite-measured normalized difference vegetation index and reanalysis temperature during 1982 2008. Results showed that the length of the growing season (LOS) increased over the analysis period; however, the role of changes at the start of the growing season (SOS) and at the end of the growing season (EOS) differed depending on the time period. On a hemispheric scale, SOS advanced by 5.2 days in the early period (1982-1999) but advanced by only 0.2 days in the later period (2000-2008). EOS was delayed by 4.3 days in the early period, and it was further delayed by another 2.3 days in the later period. The difference between SOS and EOS in the later period was due to less warming during the preseason (January-April) before SOS compared with the magnitude of warming in the preseason (June September) before EOS. At a regional scale, delayed EOS in later periods was shown. In North America, EOS was delayed by 8.1 days in the early period and delayed by another 1.3 days in the later period. In Europe, the delayed EOS by 8.2 days was more significant than the advanced SOS by 3.2 days in the later period. However, in East Asia, the overall increase in LOS during the early period was weakened in the later period. Admitting regional heterogeneity, changes in hemispheric features suggest that the longer-lasting vegetation growth in recent decades can be attributed to extended leaf senescence in autumn rather than earlier spring leaf-out. Keywords: climate change, growing season, NDVI (normalized difference vegetation index), Northern Hemisphere, phenology,

  13. Effect of soil frost on growing season nitrogen uptake by fine roots of mature trees in northern hardwood forests of the United States

    NASA Astrophysics Data System (ADS)

    Socci, A. M.; Templer, P. H.

    2010-12-01

    Forests of the northeastern United States are predicted to experience a decrease in the depth and duration of the winter snowpack over the next 100 years. Even when coupled with warmer winter air temperatures, the absence of snow as insulation can increase soil frost during the winter months. Past research has determined that there are species-level effects of soil frost on dominant forest trees. For example, in stands dominated by sugar maple (Acer saccharum), induced soil frost led to increased fine root mortality and soil nitrate leaching. Soil frost also increased fine root mortality in stands dominated by yellow birch (Betula allegheniensis), but there was no significant change in leaching of soil nitrate. We hypothesized that greater nitrogen (N) losses from stands dominated by sugar maple may be due to reduced N uptake by fine roots of this tree species. To determine the impact of increased soil freezing on fine root uptake of N, we established a snow manipulation experiment in mixed sugar maple/American beech (Fagus grandifolia) forests at the Hubbard Brook Experimental Forest in New Hampshire (n=4 paired snow-removal and reference plots; each 13m X 13m). Snow removal occurred during the first six weeks of winter over two years. During each growing season following snow removal, we used the N depletion technique to measure in situ rates of uptake of ammonium and nitrate by fine roots of sugar maple during the early, peak and late growing season. Among all sampling dates and plots, we observed significantly lower uptake of N as nitrate compared to ammonium. During the first growing season, at moderate ammonium availability (35 μM N) we observed significantly less uptake of ammonium by fine roots of sugar maple in the snow removal plots relative to the reference plots during the early growing season (April-May), with no significant differences in uptake of ammonium during the peak (July) and late (September) growing season. We observed no differences in

  14. Early-season agricultural drought: detection, assessment and monitoring using Shortwave Angle and Slope Index (SASI) data.

    PubMed

    Das, Prabir Kumar; Murthy, Srirama C; Seshasai, M V R

    2013-12-01

    Early season or crop-planting-period (ES/CPP) drought conditions have become a recurrent phenomenon in tropical countries like India, due to fluctuations in the time of onset and progression of monsoon rains. ES/CPP agricultural drought assessment is a major challenge because of the difficulties in the generation of operational products on soil moisture at larger scales. The present study analyzed the Shortwave Angle Slope Index (SASI) derived from Near Infrared and Shortwave Infrared data of Moderate Resolution Imaging Spectroradiometer, for tracking surface moisture changes and assessing the agricultural drought conditions during ES/CPP, over Andhra Pradesh state, India. It was found that in-season progression of SASI was well correlated with rainfall and crop planting patterns in different districts of the study area state in both drought and normal years. Rainfall occurrence, increase in crop planted area, and decrease in SASI were in chronological synchronization in the season. Change in SASI from positive to negative values is a unique indication of dryness to wetness shift in the season. Duration of positive SASI values indicated the persistence of agricultural drought in the crop planting period. Mean SASI values were able to discriminate an area which was planted in normal year and unplanted in drought year. SASI thresholds provide an approximate and rapid estimate of the crop planting favorable area in a region which is useful to assess the impact of drought. Thus, SASI is a potential index to strengthen the existing operational drought monitoring systems. Further work needs to be on the integration of multiple parameters-SASI, soil texture, soil depth, rainfall and cropping pattern, to evolve a geospatial product on crop planting favorable areas. Such products pave the way for quantification of drought impact on agriculture in the early part of the season, which is a major inadequacy in the current drought monitoring system. PMID:23793539

  15. Seasonal comparisons of meteorological and agricultural drought indices in Morocco using open short time-series data

    NASA Astrophysics Data System (ADS)

    Ezzine, Hicham; Bouziane, Ahmed; Ouazar, Driss

    2014-02-01

    Although the preliminary investigations of NDWI demonstrated its sensitivity to vegetation water content, drought indices based on NDWI short time-series are still understudied compared to those derived from NDVI and LST, such as VCI, SVI and TCI. On the basis of the open data, this paper introduces a new index derived from NDWI short time-series, and explores its performance for drought monitoring in Mediterranean semi-arid area. The new index, Standardized Water Index (SWI), was calculated and spatiotemporally compared to both meteorological drought index (TRMM-based SPI) and to agricultural drought index (NDVI-based SVI) for the hydrological years and autumn, winter and spring seasons during a period of 15 years (1998-2012). Furthermore, the response and spatial agreement of the meteorological and agricultural drought indices (SWI, SVI and SPI) were compared over two land use classes, rainfed agriculture and vegetation cover, for the studied years and seasons. The validation of SWI was based on in situ SPI and cereal productions. The analysis of the 336 cross-tables, proportions of concordance and Cohen's kappa coefficients indicate that SWI and SVI are concordant comparing to other combinations for hydrological years and for the three seasons. The study points that the spatial agreements of drought indices over rainfed agriculture and over vegetation cover are different. It is relatively more important in the rainfed agriculture than in the vegetation cover areas. Our results show that the agreement between vegetation drought indices and meteorological drought indices is moderated to low and the SPI is slightly more concordant with SWI when it is compared to SVI in autumn and winter seasons. The validation approach indicates that drought affected area, according to SWI, is highly correlated with cereal production. Likewise, a satisfactory correlation was revealed between SWI and in situ SPI.

  16. Non-growing-season soil respiration is controlled by freezing and thawing processes in the summer monsoon-dominated Tibetan alpine grassland

    NASA Astrophysics Data System (ADS)

    Wang, Yonghui; Liu, Huiying; Chung, Haegeun; Yu, Lingfei; Mi, Zhaorong; Geng, Yan; Jing, Xin; Wang, Shiping; Zeng, Hui; Cao, Guangmin; Zhao, Xinquan; He, Jin-Sheng

    2014-10-01

    The Tibetan alpine grasslands, sharing many features with arctic tundra ecosystems, have a unique non-growing-season climate that is usually dry and without persistent snow cover. Pronounced winter warming recently observed in this ecosystem may significantly alter the non-growing-season carbon cycle processes such as soil respiration (Rs), but detailed measurements to assess the patterns, drivers of, and potential feedbacks on Rs have not been made yet. We conducted a 4 year study on Rs using a unique Rs measuring system, composed of an automated soil CO2 flux sampling system and a custom-made container, to facilitate measurements in this extreme environment. We found that in the nongrowing season, (1) cumulative Rs was 82-89 g C m-2, accounting for 11.8-13.2% of the annual total Rs; (2) surface soil freezing controlled the diurnal pattern of Rs and bulk soil freezing induced lower reference respiration rate (R0) and temperature sensitivity (Q10) than those in the growing season (0.40-0.53 versus 0.84-1.32 µmol CO2 m-2 s-1 for R0 and 2.5-2.9 versus 2.9-5.6 for Q10); and (3) the intraannual variation in cumulative Rs was controlled by accumulated surface soil temperature. We found that in the summer monsoon-dominated Tibetan alpine grassland, surface soil freezing, bulk soil freezing, and accumulated surface soil temperature are the day-, season-, and year-scale drivers of the non-growing-season Rs, respectively. Our results suggest that warmer winters can trigger carbon loss from this ecosystem because of higher Q10 of thawed than frozen soils.

  17. The warming-induced increase of growing-season freezing event and its effect on the survival and growth of treeline seedlings in the Sergyemla Mountains, Southeast Tibet

    NASA Astrophysics Data System (ADS)

    Shen, W.; Zhang, L.; Liu, X.; Luo, T.

    2013-12-01

    Seedling establishment is important to the formation and dynamics of alpine treeline. How can we understand the limitation to the survival and growth of seedlings at and above treeline under a warmer climate? In this study, we conducted a 4-yr reciprocal transplant experiment of seed-based fir and root-sprouting juniper seedlings on opposite slopes of a valley in the Sergyemla Mountains, where annual mean air-temperature differed by 0.5-2.1 K and annual precipitation was similar. We aim to test the hypotheses that the warmer climate on the south-facing slope generally has more severe growing-season freezing events, and the seed-based fir seedlings are especially vulnerable to the warming-induced increase of freezing days in the early growing season. The frequency, intensity and duration of the growing-season freezing events across site habitats generally increased from north- to south-facing slopes. The freezing days in the early growing season (April-June) were mainly determined by daily minimum net radiation and relative humidity, and positively correlated with annual mean air-temperature across sites and years. The survival rates of transplanted fir seedlings on the south-facing slope greatly decreased by <60% in forested habitat and by <40% in non-forested habitat, while their survival rates on the north-facing slope did not change in forested habitat and slowly decreased by 85% in non-forested habitat. The survival rates of transplanted juniper seedlings decreased by 68%-84% with unclear change trends among different slopes and habitats. In pooled data across sites and years, annual top-shoot growth rates decreased in fir seedlings but varied little in juniper seedlings with increasing freezing days in the early growing season. The data supported our hypotheses. The warming-enhanced difficulty of seedling establishment above treeline can explain why the fir treeline position did not advance with climatic warming in past 200 years.

  18. Climate change in winter versus the growing-season leads to different effects on soil microbial activity in northern hardwood forests

    NASA Astrophysics Data System (ADS)

    Sorensen, P. O.; Templer, P. H.; Finzi, A.

    2014-12-01

    Mean winter air temperatures have risen by approximately 2.5˚ C per decade over the last fifty years in the northeastern U.S., reducing the maximum depth of winter snowpack by approximately 26 cm over this period and the duration of winter snow cover by 3.6 to 4.2 days per decade. Forest soils in this region are projected to experience a greater number of freeze-thaw cycles and lower minimum winter soil temperatures as the depth and duration of winter snow cover declines in the next century. Climate change is likely to result not only in lower soil temperatures during winter, but also higher soil temperatures during the growing-season. We conducted two complementary experiments to determine how colder soils in winter and warmer soils in the growing-season affect microbial activity in hardwood forests at Harvard Forest, MA and Hubbard Brook Experimental Forest, NH. A combination of removing snow via shoveling and buried heating cables were used to induce freeze-thaw events during winter and to warm soils 5˚C above ambient temperatures during the growing-season. Increasing the depth and duration of soil frost via snow-removal resulted in short-term reductions in soil nitrogen (N) production via microbial proteolytic enzyme activity and net N mineralization following snowmelt, prior to tree leaf-out. Declining mass specific rates of carbon (C) and N mineralization associated with five years of snow removal at Hubbard Brook Experimental Forest may be an indication of microbial physiological adaptation to winter climate change. Freeze-thaw cycles during winter reduced microbial extracellular enzyme activity and the temperature sensitivity of microbial C and N mineralization during the growing-season, potentially offsetting nutrient and soil C losses due to soil warming in the growing-season. Our multiple experimental approaches show that winter climate change is likely to contribute to reduced microbial activity in northern hardwood forests.

  19. Seasonal Variation in Cortisol Biomarkers in Hispanic Mothers Living in an Agricultural Region

    PubMed Central

    Smith, Marissa N.; Wilder, Carly S.; Griffith, William C.; Workman, Tomomi; Thompson, Beti; Dills, Russel; Onstad, Gretchen; Vredevoogd, Melinda; Vigoren, Eric M.; Faustman, Elaine M.

    2016-01-01

    Context Characterization of stress exposure requires an understanding seasonal variability in stress biomarkers. Objective To compare acute and chronic stress biomarkers between two seasons in a cohort of rural, Hispanic mothers. Methods Stress questionnaires and cortisol measurements (hair, blood, saliva) were collected in the summer and fall. Results Cortisol biomarkers were significantly different and stress questionnaires were significantly correlated between seasons. Discussion The variability in cortisol and relative stability of questionnaires between seasons may indicate that cortisol responds to subtle stressors not addressed in questionnaires. Conclusions There are significant differences in stress biomarkers in our cohort between seasons. PMID:26329526

  20. Plant phenological responses to a long-term experimental extension of growing season and soil warming in the tussock tundra of Alaska.

    PubMed

    Khorsand Rosa, Roxaneh; Oberbauer, Steven F; Starr, Gregory; Parker La Puma, Inga; Pop, Eric; Ahlquist, Lorraine; Baldwin, Tracey

    2015-12-01

    Climate warming is strongly altering the timing of season initiation and season length in the Arctic. Phenological activities are among the most sensitive plant responses to climate change and have important effects at all levels within the ecosystem. We tested the effects of two experimental treatments, extended growing season via snow removal and extended growing season combined with soil warming, on plant phenology in tussock tundra in Alaska from 1995 through 2003. We specifically monitored the responses of eight species, representing four growth forms: (i) graminoids (Carex bigellowii and Eriophorum vaginatum); (ii) evergreen shrubs (Ledum palustre, Cassiope tetragona, and Vaccinium vitis-idaea); (iii) deciduous shrubs (Betula nana and Salix pulchra); and (iv) forbs (Polygonum bistorta). Our study answered three questions: (i) Do experimental treatments affect the timing of leaf bud break, flowering, and leaf senescence? (ii) Are responses to treatments species-specific and growth form-specific? and (iii) Which environmental factors best predict timing of phenophases? Treatment significantly affected the timing of all three phenophases, although the two experimental treatments did not differ from each other. While phenological events began earlier in the experimental plots relative to the controls, duration of phenophases did not increase. The evergreen shrub, Cassiope tetragona, did not respond to either experimental treatment. While the other species did respond to experimental treatments, the total active period for these species did not increase relative to the control. Air temperature was consistently the best predictor of phenology. Our results imply that some evergreen shrubs (i.e., C. tetragona) will not capitalize on earlier favorable growing conditions, putting them at a competitive disadvantage relative to phenotypically plastic deciduous shrubs. Our findings also suggest that an early onset of the growing season as a result of decreased snow cover

  1. Forest Gaps Inhibit Foliar Litter Pb and Cd Release in Winter and Inhibit Pb and Cd Accumulation in Growing Season in an Alpine Forest

    PubMed Central

    He, Jie; Yang, Wanqin; Li, Han; Xu, Liya; Ni, Xiangyin; Tan, Bo; Zhao, Yeyi; Wu, Fuzhong

    2015-01-01

    Aims The release of heavy metals (such as Pb and Cd) from foliar litter play an important role in element cycling in alpine forest ecosystems. Although natural forest gaps could play important roles in the release of heavy metals from foliar litter by affecting the snow cover during the winter and solar irradiation during the growing season, few studies have examined these potential roles. The objectives of this study were to document changes in Pb and Cd dynamics during litter decomposition in the center of gaps and under closed canopies and to investigate the factors that controlled these changes during the winter and growing seasons. Methods Senesced foliar litter from six dominant species, including Kangding willow (Salix paraplesia), Masters larch (Larix mastersiana), Mingjiang fir (Abies faxoniana), Alpine azalea (Rhododendron lapponicum), Red birch (Betula albosinensis) and Mourning cypress (Sabina saltuaria), was placed in litterbags and incubated between the gap center and closed canopy conditions in an alpine forest in the eastern region of the Tibetan Plateau. The litterbags were sampled at the snow formation stage, snow coverage stage, snow melt stage and during the growing season. The Pb and Cd concentrations in the sampled foliar litter were determined by acid digestion (HNO3/HClO4). Important findings Over one year of decomposition, Pb accumulation and Cd release from the foliar litter occurred, regardless of the foliar litter species. However, Pb and Cd were both released from the foliar litter during the winter and accumulated during the growing season. Compared with the gap center and the canopy gap edge, the extended gap edge and the closed canopy showed higher Pb and Cd release rates in winter and higher Pb and Cd accumulation rates during the growing season, respectively. Statistical analyses indicate that the dynamics of Pb were significantly influenced by frequent freeze–thaw cycles in winter and appropriate hydrothermal conditions during

  2. Leaf Tissue C:N and Soil N are Modified by Growing Season and Goose Grazing Phenology in a Sub-Arctic Coastal Wetland of Western Alaska

    NASA Astrophysics Data System (ADS)

    Choi, R. T.; Beard, K. H.; Leffler, A. J.; Schmutz, J. A.; Welker, J. M.

    2014-12-01

    Climate change in Arctic wetlands is resulting in a widening phenological mismatch between the onset of the growing season and the arrival and hatch date of migratory geese, the primary consumers in the system. During the past three decades, the growing season has advanced but geese have not advanced arrival or hatch date at the same rate. Geese now arrive into a system that has been growing longer than in the past with potential changes in forage quality because sedges have their highest nutrient density shortly following emergence. One potential concomitant result of this phenological gap is altered carbon to nitrogen ratio (C:N) of leaf tissue being returned to the ecosystem as feces that is more N-poor. Altering the C:N of these inputs can further influence C and N cycling in the system. We examine the influence of advanced growing season and different arrival times by black brant on leaf and soil C:N ratio and soil N-form. Our experiment consists of six blocks with nine study plots each. Half the plots are warmed to advance the growing season. Two plots each receive early, typical, late, and no grazing; one plot is a control that is not warmed and grazing is natural. Leaf tissue was collected to determine C and N concentration using an elemental analyzer. Anion and cation exchange membranes were used to monitor inorganic N forms in soil; samples were analyzed via fluorescence following extraction. Soil water collected from lysimeters was analyzed for organic N. Warming advanced plant growth between one and two weeks and resulted in higher C:N of leaf tissue Geese maintained 'grazing lawns', areas of exceptionally short vegetation, where plants had high N compared to non-grazed areas. Grazing early in the season promoted higher N content of leaves and soil while grazing late had little influence on N. The timing of the growing season and grazing both have important implications for C and N in this system.

  3. Ten Years of Growing Season Water, Energy and Carbon Exchange From an Oil sands Reclamation Site, Fort McMurray, Alberta

    NASA Astrophysics Data System (ADS)

    Carey, S. K.; Drewitt, G. B.

    2013-12-01

    The oil sands mining industry in Canada has made a commitment to restore disturbed areas to an equivalent capability to that which existed prior to mining. Certification requires successful reclamation, which can in part be evaluated through long-term ecosystem studies. A reclamation site, informally named South Bison Hill (SBH) has had growing season water, energy and carbon fluxes measured via the eddy covariance method for 10 years since establishment. SBH was capped with a 0.2 m peat-glacial till mixture overlying 0.8 m of reworked glacial till soil. The site was seeded to barley cultivar (Hordeum spp.) in the summer of 2002 and later planted to white spruce (Picea glauca) and aspen (Populus spp.) in the summer/fall of 2004. Since 2007, the major species atop SBH has been aspen, and by 2012 was on average ~ 4 m in height. Climatically, mean growing temperature did not vary greatly, yet there was considerable difference in rainfall among years, with 2012 having the greatest rainfall at 321 mm, whereas 2011 and 2007 were notably dry at 180 and 178 mm, respectively. The partitioning of energy varied among years, but the fraction of latent heat as a portion of net radiation increased with the establishment of aspen, along with concomitant increases in LAI and growing season net ecosystem exchange (NEE). Peat growing season ET was smallest in 2004 at 2.3 mm/d and greatest in 2010 at ~3.9 mm/d. ET rates showed a marked increase in 2008 corresponding with the increase in LAI attributed to the aspen cover. Since the establishment of a surface cover and vegetation in 2003, SBH has been a growing season sink for carbon dioxide. Values of NEE follow similar patterns to those of ET, with values gradually becoming more negative (greater carbon uptake) as the aspen forest established. Comparison with other disturbed and undisturbed boreal aspen stands show that SBH exhibits similar water, energy and carbon flux patterns during the growing season.

  4. Annual and seasonal differences in pesticide mixtures within channelized agricultural headwater streams in central Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Only a limited amount of information on pesticide mixtures within agricultural headwater streams is available. A greater understanding of the characteristics of pesticide mixtures and their spatial and temporal trends within agricultural headwater streams is needed to evaluate the risks of pesticid...

  5. Bayesian analysis of the species-specific lengthening of the growing season in two European countries and the influence of an insect pest

    NASA Astrophysics Data System (ADS)

    Menzel, Annette; Estrella, Nicole; Heitland, Werner; Susnik, Andreja; Schleip, Christoph; Dose, Volker

    2008-01-01

    A recent lengthening of the growing season in mid and higher latitudes of the northern hemisphere is reported as a clear indicator for climate change impacts. Using data from Germany (1951-2003) and Slovenia (1961-2004), we study whether changes in the start, end, and length of the growing season differ among four deciduous broad-leaved tree species and countries, how the changes are related to temperature changes, and what might be the confounding effects of an insect attack. The functional behaviour of the phenological and climatological time series and their trends are not analysed by linear regression, but by a new Bayesian approach taking into account different models for the functional description (one change-point, linear, constant models). We find advanced leaf unfolding in both countries with the same species order (oak > horse chestnut, beech, and birch). However, this advance is non linear over time and more apparent in Germany with clear change-points in the late 1970s, followed by marked advances (on average 3.67 days decade-1 in the 2000s). In Slovenia, we find a more gradual advance of onset dates (on average 0.8 days decade-1 in the 2000s). Leaf colouring of birch, beech, and oak has been slightly delayed in the last 3 decades, especially in Germany, however with no clear functional behaviour. Abrupt changes in leaf colouring dates of horse chestnut with recent advancing onset dates can be linked across countries to damage by a newly emerging pest, the horse chestnut leaf-miner ( Cameraria ohridella). The lengthening of the growing season, more distinct in Germany than in Slovenia (on average 4.2 and 1.0 days decade-1 in the 2000s, respectively), exhibits the same species order in both countries (oak > birch > beech). Damage by horse chestnut leaf-miner leads to reduced lengthening (Germany) and drastic shortening (Slovenia) of the horse chestnut growing season (-12 days decade-1 in the 2000s). Advanced spring leaf unfolding and lengthening of the

  6. Sensory and chemical flavor analyses of tomato genotypes grown in Florida during three different growing seasons in multiple years

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-eight tomato genotypes were analyzed for sensory attributes “sweet”, “sour” and “overall flavor” over seven years, one to three seasons per year (March, June and December) as well as for physical and chemical flavor-related attributes including color, sugars, acids and aroma volatiles (6-7 ye...

  7. Downscaling large-scale NCEP CFS to resolve fine-scale seasonal precipitation and extremes for the crop growing seasons over the southeastern United States

    NASA Astrophysics Data System (ADS)

    Lim, Young-Kwon; Cocke, Steven; Shin, D. W.; Schoof, Justin T.; Larow, Timothy E.; O'Brien, James J.

    2010-08-01

    Seasonally predicted precipitation at a resolution of 2.5° was statistically downscaled to a fine spatial scale of ~20 km over the southeastern United States. The downscaling was conducted for spring and summer, when the fine-scale prediction of precipitation is typically very challenging in this region. We obtained the global model precipitation for downscaling from the National Center for Environmental Prediction/Climate Forecast System (NCEP/CFS) retrospective forecasts. Ten member integration data with time-lagged initial conditions centered on mid- or late February each year were used for downscaling, covering the period from 1987 to 2005. The primary techniques involved in downscaling are Cyclostationary Empirical Orthogonal Function (CSEOF) analysis, multiple regression, and stochastic time series generation. Trained with observations and CFS data, CSEOF and multiple regression facilitated the identification of the statistical relationship between coarse-scale and fine-scale climate variability, leading to improved prediction of climate at a fine resolution. Downscaled precipitation produced seasonal and annual patterns that closely resemble the fine resolution observations. Prediction of long-term variation within two decades was improved by the downscaling in terms of variance, root mean square error, and correlation. Relative to the coarsely resolved unskillful CFS forecasts, the proposed downscaling drove a significant reduction in wet biases, and correlation increased by 0.1-0.5. Categorical predictability of seasonal precipitation and extremes (frequency of heavy rainfall days), measured with the Heidke skill score (HSS), was also improved by the downscaling. For instance, domain averaged HSS for two category predictability by the downscaling are at least 0.20, while the scores by the CFS are near zero and never exceed 0.1. On the other hand, prediction of the frequency of subseasonal dry spells showed limited improvement over half of the Georgia and

  8. Effect of Season on the Persistence of Bacterial Pathogens in Runoff from Agricultural Plots

    EPA Science Inventory

    Runoff from agricultural fields undergoing manure applications may carry a variety of chemical and microbial contaminants that compromise water quality and increase the possibility of human exposure to pathogenic microorganisms when recreational waters are impacted. A series of r...

  9. Seasonal variation of macro and trace mineral contents in 14 browse species that grow in northeastern Mexico.

    PubMed

    Ramirez, R G.; Haenlein, G F.W.; Núñez-González, M A.

    2001-02-01

    Leaves and twigs from shrub species consumed by range goats: Acacia berlandieri, Acacia farnesiana, Acacia greggii, Acacia rigidula, Celtis pallida, Cercidium macrum, Condalia obovata, Cordia boissieri, Desmanthus virgathus, Leucaena leucocephala, Leucophyllum texanum, Opuntia lindehimieri, Porlieria angustifolia, Prosopis glandulosa, and Ziziphus obtusifolia were evaluated for comparative seasonal contents of Ca, P, Mg K, Zn, Mn, Cu and Fe. Plants were collected in summer (September 12, 1992), fall (November 20, 1992), winter (February 20, 1993) and spring (May 22, 1993) in Marín, County, Nuevo Leon, Mexico. During spring and summer mineral concentrations were higher in general. Only Ca, Mg, K, and Fe were in substantial amounts in all seasons to meet adult goat requirements. With the exception of spring, shrubs had extremely low P concentrations. Manganese, Cu and Zn in most plants had low marginal levels to meet adult goat requirements. Moreover, potential intake of P, Mn, Cu and Zn in shrub species by goats weighing 50kg BW consuming 2.0kg per day DM was low. However, plants such as D. virgathus, L. texanum, P. glandulosa, L. leucocephala and C. macrum can be considered prominent components in diets of range goats because of their high mineral concentrations. It appears that ration formulations for range goats in northeastern Mexico should include P, Mn, Cu and Zn in all seasons of the year. PMID:11182308

  10. Soil Bacterial Community Response to Differences in Agricultural Management along with Seasonal Changes in a Mediterranean Region

    PubMed Central

    Bevivino, Annamaria; Paganin, Patrizia; Bacci, Giovanni; Florio, Alessandro; Pellicer, Maite Sampedro; Papaleo, Maria Cristiana; Mengoni, Alessio; Ledda, Luigi; Fani, Renato; Benedetti, Anna; Dalmastri, Claudia

    2014-01-01

    Land-use change is considered likely to be one of main drivers of biodiversity changes in grassland ecosystems. To gain insight into the impact of land use on the underlying soil bacterial communities, we aimed at determining the effects of agricultural management, along with seasonal variations, on soil bacterial community in a Mediterranean ecosystem where different land-use and plant cover types led to the creation of a soil and vegetation gradient. A set of soils subjected to different anthropogenic impact in a typical Mediterranean landscape, dominated by Quercus suber L., was examined in spring and autumn: a natural cork-oak forest, a pasture, a managed meadow, and two vineyards (ploughed and grass covered). Land uses affected the chemical and structural composition of the most stabilised fractions of soil organic matter and reduced soil C stocks and labile organic matter at both sampling season. A significant effect of land uses on bacterial community structure as well as an interaction effect between land uses and season was revealed by the EP index. Cluster analysis of culture-dependent DGGE patterns showed a different seasonal distribution of soil bacterial populations with subgroups associated to different land uses, in agreement with culture-independent T-RFLP results. Soils subjected to low human inputs (cork-oak forest and pasture) showed a more stable bacterial community than those with high human input (vineyards and managed meadow). Phylogenetic analysis revealed the predominance of Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes phyla with differences in class composition across the site, suggesting that the microbial composition changes in response to land uses. Taken altogether, our data suggest that soil bacterial communities were seasonally distinct and exhibited compositional shifts that tracked with changes in land use and soil management. These findings may contribute to future searches for bacterial bio-indicators of soil

  11. Can reduced stocking rates and natural forage utilization produce market sized catfish from fingerlings in one growing season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to determine the feasibility of growing marketable channel catfish Ictalurus punctatus from pond-run fingerlings (15.9 g/fish) using low stocking densities (7,413 or 14,826 fish/ha) and electrified bug lights to enhance natural forage available to fish. Even at low sto...

  12. LATITUDINAL AND SEASONAL VARIATION IN CALCULATED ULTRAVIOLET-B IRRADIANCE IN THE RICE-GROWING REGIONS OF ASIA

    EPA Science Inventory

    Ultraviolet-B (UV-B, 280-329 nm) irradiance was calculated for more than 1200 sites in Asia to characterize the spatial and temporal variation in the present UV-B climate for rice-growing regions. he analytical model of Green et al. was used to compute UV-B irradiance for clear s...

  13. Connecting Seasonal Riparian Buffer Metrics and Nitrogen Concentrations in a Pulse-Driven Agricultural System

    EPA Science Inventory

    Riparian buffers have been well studied as best management practices for nutrient reduction at field scales yet their effectiveness for bettering water quality at watershed scales has been difficult to determine. Seasonal dynamics of the stream network are often overlooked when ...

  14. Seasonal atrazine contamination of drinking water in pig-breeding farm surroundings in agricultural and industrial areas of Croatia.

    PubMed

    Gojmerac, T; Kartal, B; Bilandzic, N; Roic, B; Rajkovic-Janje, R

    1996-02-01

    Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) a s-triazine herbicide, has been widely used in Croatian agriculture. Due to atrazine extensive use and its biodegradation in nature within at least one year (Klassen and Kodoum 1979), atrazine residues are found in ground, surface, drain and drinking water (Vidacek et al. 1994; Gojmerac et al. 1994). Groundwater downgradient from atrazine treated fields may show seasonal concentration peaks which could exceed the safe level (Wehtje et al. 1983). Therefore, the use of atrazine includes permanent control of its residues in water, particularly in relation to its use as a herbicidal chemical and groundwater contamination (Graham 1991). Furthermore, the presence of atrazine in the environment and its possible ingestion via the water, food and feed chain, may present a risk for the animal and human health. The analysis of atrazine residues in soil can be performed by either colorimetry or high performance liquid chromatography (HPLC) (Vickrey et al. 1980), and in water, soil and food by immunoassay in comparison with HPLC or gas chromatography/mass spectrometry (GS-MS) (Bushway et al. 1988; Bushway et al. 1989; Bushway et al. 1992; Thurman et al. 1990). We describe the use of enzyme-linked immunosorbent assay (ELISA) for one-year seasonal monitoring of atrazine residues in drinking water from two differently situated pig-breeding farms (agricultural and industrial areas) in Croatia. Results obtained by ELISA were compared to those produced by HPLC. PMID:8720093

  15. Climate change, growing season water deficit and vegetation activity along the north-south transect of eastern China from 1982 through 2006

    NASA Astrophysics Data System (ADS)

    Sun, P.; Yu, Z.; Liu, S.; Wei, X.; Wang, J.; Zegre, N.; Liu, N.

    2012-10-01

    Considerable work has been done to examine the relationship between environmental constraints and vegetation activities represented by the remote sensing-based normalized difference vegetation index (NDVI). However, the relationships along either environmental or vegetational gradients are rarely examined. The aim of this paper was to identify the vegetation types that are potentially susceptible to climate change through examining their interactions between vegetation activity and evaporative water deficit. We selected 12 major vegetation types along the north-south transect of eastern China (NSTEC), and tested their time trends in climate change, vegetation activity and water deficit during the period 1982-2006. The result showed significant warming trends accompanied by general precipitation decline in the majority of vegetation types. Despite that the whole transect increased atmospheric evaporative demand (ET0) during the study period, the actual evapotranspiration (ETa) showed divergent trends with ET0 in most vegetation types. Warming and water deficit exert counteracting controls on vegetation activity. Our study found insignificant greening trends in cold temperate coniferous forest (CTCF), temperate deciduous shrub (TDS), and three temperate herbaceous types including the meadow steppe (TMS), grass steppe (TGS) and grassland (TG), where warming exerted more effect on NDVI than offset by water deficit. The increasing growing season water deficit posed a limitation on the vegetation activity of temperate coniferous forest (TCF), mixed forest (TMF) and deciduous broad-leaved forest (TDBF). Differently, the growing season brownings in subtropical or tropical forests of coniferous (STCF), deciduous broad-leaved (SDBF), evergreen broad-leaved (SEBF) and subtropical grasslands (STG) were likely attributed to evaporative energy limitation. The growing season water deficit index (GWDI) has been formulated to assess ecohydrological equilibrium and thus indicating

  16. Seasonal Patterns of Nitrogen and Phosphorus Losses in Agricultural Drainage Ditches in Northern Mississippi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drainage ditches convey nutrient laden waters from agricultural landscapes to receiving waters. Surface drainage ditches are landscape features that have been overlooked for non-point source pollution mitigation of receiving waters. The objective of this study was to determine the nitrogen and phosp...

  17. Application of seasonal climate forecasts in agricultural crop monitoring in Brazil

    NASA Astrophysics Data System (ADS)

    de Avila, A. M. H.; Pereira, V. R.; Lopes, F. A.

    2014-12-01

    This work is investigating the contribution of seasonal climate forecasts of Eta regional climate model to support crops in Brazil. The weather conditions are directed related with the crop yield, being a basic parameter for its forecast. The southern region has a subtropical climate and is the major national producer of rice and wheat and also is the second one for soybean, bean and corn. The Eta seasonal forecast model data for southern Brazil was evaluated from 2001 to 2010. Observed data from National and state meteorological agencies were used to evaluate the monthly model performance. The model performance was evaluated by calculating two parameters. The Root Mean Square Error (RMSE) was used to evaluate the monthly forecast averages and the observed precipitation standard deviation. The Skill Score Climatology (SSC) was used to compare the accuracy between the forecast and the climatology. The RMSE showed that in some locations the predicted values by the model were closer to the observed. The SSC showed a systematic error for the predicted values by the Eta seasonal model. This behavior indicates that the climatological analysis is more accurate to predict the monthly climate than the ETA model forecast. Also the consecutive negative bias was observed in some locations that can be corrected removing the systematic error.

  18. Agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agriculture within the United States is varied and produces a large value ($200 billion in 2002) of production across a wide range of plant and animal production systems. Because of this diversity, changes in climate will likely impact agriculture throughout the United States. Climate affects crop, ...

  19. Net ecosystem exchange, gross primary production, and ecosystem respiration of carbon dioxide during barley growing season in rice-barley paddy field of Korea

    NASA Astrophysics Data System (ADS)

    Jung, M.; Shim, K.; Min, S.; Kim, Y.; Kim, S.; So, K.

    2013-12-01

    This study was conducted to measure carbon dioxide exchange between customarily cultivated rice-barley double cropping paddy field and the atmosphere during barley growing season (October 2012 and June 2013) and to estimate carbon dioxide fluxes using agro-meteorological factors (temperature, net radiation etc. ) and barley biomass. The carbon dioxide fluxes were quantified by eddy covariance technique in paddy fields with rice-barley double cropping system, located at the Gimje flux site in the southwestern coast of Korea. The total values of net ecosystem carbon dioxide exchange (NEE), gross primary production (GPP), and ecosystem respiration (Re) were -100.6, 782.7, and 682.5 g C m-2 during barley growing season, respectively. The NEE was tended to keep between 0 and 5 g C m-2 d-1 from sowing date (Oct. 21, 2012) to winter rest stage (Dec. 3, 2012 to Feb. 22, 2013), and gradually decreased in tillering stage (Feb. 23, 2013 to May 5, 2013) with its maximum around heading date, and then started to increase in ripening stage (May 6, 2013 to Jun. 8, 2013). The soil temperature was strongly correlated with the Re (r2=0.86), while the net radiation showed the weak relationship with the GPP during the emergence, seedling, and winter rest stage. The aboveground biomass of barley was significantly correlated with the values of NEE (r2=0.79), GPP (r2=0.83), and Re (r2=0.77), respectively.

  20. Interactions between light and growing season temperatures on, growth and development and gas exchange of Semillon (Vitis vinifera L.) vines grown in an irrigated vineyard.

    PubMed

    Greer, Dennis H; Weedon, Mark M

    2012-05-01

    High-light intensities and temperatures of the warm climate regions of Australia and elsewhere have a major effect on the growth and development of grapevines (Vitis vinifera L.). The objective of this research was to assess interactions between the light and seasonal temperatures by shading some vines and comparing these with vines exposed to high-light intensities. Canopy temperatures were monitored using infrared radiometers and budbreak, phenology, growth, yield, berry ripening and gas exchange determined over three growing seasons. Results showed canopies were generally about 4 °C cooler than air and shading extended this cooling. Irradiance, irrespective of seasonal temperatures, had no effect on time of budbreak, shoot phenology, stem growth, yield and bunch fresh weights while bunch and leaf dry weights were reduced in low-light. Bunch ripening was initially delayed by low-light but thereafter the ripening process was highly temperature-dependent. Rates increased linearly with increasing temperature in both low and high-light and were optimal at about 35 °C. Maximum photosynthetic capacity was impaired by low irradiance, in accordance with shade leaf attributes, and attributable to stomatal closure. No effects of the low photosynthetic capacity apparently carried-over to sugar accumulation, consistent with the strong sink capacity of bunches. PMID:22381656

  1. The contribution of soil biogenic NO emissions from a managed hyper-arid ecosystem to the regional NO2 emissions during growing season

    NASA Astrophysics Data System (ADS)

    Mamtimin, B.; Badawy, M.; Behrendt, T.; Meixner, F. X.; Wagner, T.

    2015-12-01

    A study was carried out to understand the contributions of soil biogenic NO emissions from managed (fertilized and irrigated) hyper-arid ecosystem in NW-China to the regional NO2 emissions during growing season. Soil biogenic NO emissions were quantified by laboratory incubation of corresponding soil samples. We have developed the Geoscience General Tool Package (GGTP) to obtain soil temperature, soil moisture and biogenic soil NO emission at oasis scale. Bottom-up anthropogenic NO2 emissions have been scaled down from annual to monthly values to compare mean monthly soil biogenic NO2 emissions. The top-down emission estimates have been derived from satellite observations compared then with the bottom-up emission estimates (anthropogenic and biogenic). The results show that the soil biogenic emissions of NO2 during the growing period are (at least) equal until twofold of the related anthropogenic sources. We found that the grape soils are the main summertime contributor to the biogenic NO emissions of study area, followed by cotton soils. The top-down and bottom-up emission estimates were shown to be useful methods to estimate the monthly/seasonal cycle of the total regional NO2 emissions. The resulting total NO2 emissions show a strong peak in winter and a secondary peak in summer, providing confidence in the method. These findings provide strong evidence that biogenic emissions from soils of managed drylands (irrigated and fertilized) in the growing period can be much more important contributors to the regional NO2 budget (hence to regional photochemistry) of dryland regions than thought before.

  2. Differentiating transpiration from evaporation in seasonal agricultural wetlands and the link to advective fluxes in the root zone

    USGS Publications Warehouse

    Bachand, P.A.M.; S. Bachand; Fleck, Jacob A.; Anderson, Frank E.; Windham-Myers, Lisamarie

    2014-01-01

    The current state of science and engineering related to analyzing wetlands overlooks the importance of transpiration and risks data misinterpretation. In response, we developed hydrologic and mass budgets for agricultural wetlands using electrical conductivity (EC) as a natural conservative tracer. We developed simple differential equations that quantify evaporation and transpiration rates using flowrates and tracer concentrations atwetland inflows and outflows. We used two ideal reactormodel solutions, a continuous flowstirred tank reactor (CFSTR) and a plug flow reactor (PFR), to bracket real non-ideal systems. From those models, estimated transpiration ranged from 55% (CFSTR) to 74% (PFR) of total evapotranspiration (ET) rates, consistent with published values using standard methods and direct measurements. The PFR model more appropriately represents these nonideal agricultural wetlands in which check ponds are in series. Using a fluxmodel, we also developed an equation delineating the root zone depth at which diffusive dominated fluxes transition to advective dominated fluxes. This relationship is similar to the Peclet number that identifies the dominance of advective or diffusive fluxes in surface and groundwater transport. Using diffusion coefficients for inorganic mercury (Hg) and methylmercury (MeHg) we calculated that during high ET periods typical of summer, advective fluxes dominate root zone transport except in the top millimeters below the sediment–water interface. The transition depth has diel and seasonal trends, tracking those of ET. Neglecting this pathway has profound implications: misallocating loads along different hydrologic pathways; misinterpreting seasonal and diel water quality trends; confounding Fick's First Law calculations when determining diffusion fluxes using pore water concentration data; and misinterpreting biogeochemicalmechanisms affecting dissolved constituent cycling in the root zone. In addition,our understanding of internal

  3. Differentiating transpiration from evaporation in seasonal agricultural wetlands and the link to advective fluxes in the root zone.

    PubMed

    Bachand, P A M; Bachand, S; Fleck, J; Anderson, F; Windham-Myers, L

    2014-06-15

    The current state of science and engineering related to analyzing wetlands overlooks the importance of transpiration and risks data misinterpretation. In response, we developed hydrologic and mass budgets for agricultural wetlands using electrical conductivity (EC) as a natural conservative tracer. We developed simple differential equations that quantify evaporation and transpiration rates using flow rates and tracer concentrations at wetland inflows and outflows. We used two ideal reactor model solutions, a continuous flow stirred tank reactor (CFSTR) and a plug flow reactor (PFR), to bracket real non-ideal systems. From those models, estimated transpiration ranged from 55% (CFSTR) to 74% (PFR) of total evapotranspiration (ET) rates, consistent with published values using standard methods and direct measurements. The PFR model more appropriately represents these non-ideal agricultural wetlands in which check ponds are in series. Using a flux model, we also developed an equation delineating the root zone depth at which diffusive dominated fluxes transition to advective dominated fluxes. This relationship is similar to the Peclet number that identifies the dominance of advective or diffusive fluxes in surface and groundwater transport. Using diffusion coefficients for inorganic mercury (Hg) and methylmercury (MeHg) we calculated that during high ET periods typical of summer, advective fluxes dominate root zone transport except in the top millimeters below the sediment-water interface. The transition depth has diel and seasonal trends, tracking those of ET. Neglecting this pathway has profound implications: misallocating loads along different hydrologic pathways; misinterpreting seasonal and diel water quality trends; confounding Fick's First Law calculations when determining diffusion fluxes using pore water concentration data; and misinterpreting biogeochemical mechanisms affecting dissolved constituent cycling in the root zone. In addition, our understanding of

  4. VIRTUAL COLLECTION OF AGRICULTURAL CROPS, THEIR WILD-GROWING RELATIVES AND PEST ORGANISMS WITHIN THE FORMER SOVIET UNION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The first revision of the Agricultural Atlas of the former USSR territories is now nearing completion. It will consist of maps and associated metadata, biological descriptions, including photographs, and GIS exploratory software. The Atlas presents maps reflecting the distribution of major and minor...

  5. Radionuclide Concentrations in Soils and Vegetation at Low-Level Radioactive Waste Disposal Area G during the 1997 Growing Season

    SciTech Connect

    L. Naranjo, Jr.; P. R. Fresquez; R. J. Wechsler

    1998-08-01

    Soil and overstory and understory vegetation (washed and unwashed) collected at eight locations within and around Area G-a low-level radioactive solid-waste disposal facility at Los Alamos National Laboratory-were analyzed for 3H, 238Pu, 239Pu, 137CS, 234U, 235U, 228AC, Be, 214Bi, 60Co, 40& 54Mn, 22Na, 214Pb and 208Tl. In general, most radionuclide concentrations, with the exception of 3Ef and ~9Pu, in soils and overstory and understory vegetation collected from within and around Area G were within upper (95'%) level background concentrations. Although 3H concentrations in vegetation from most sites were significantly higher than background (>2 pCi mL-l), concentrations decreased markedly in comparison to last year's results. The highest `H concentration in vegetation was detected from a juniper tree that was growing over tritium shaft /+150; it contained 530,000 pCi 3H mL-l. Also, as in the pas~ the transuranic waste pad area contained the highest levels of 239Pu in soils and in understory vegetation as compared to other areas at Area G.

  6. Seasonal synchronicity of algal assemblages in three Midwestern agricultural streams having varying concentrations of atrazine, nutrients, and sediment.

    PubMed

    Andrus, J Malia; Winter, Diane; Scanlan, Michael; Sullivan, Sean; Bollman, Wease; Waggoner, J B; Hosmer, Alan J; Brain, Richard A

    2013-08-01

    Numerous studies characterizing the potential effects of atrazine on algal assemblages have been conducted using micro- or mesocosms; however, few evaluations focused on in situ lotic algal communities, potentially confounding risk assessment conclusions. This exploratory study, conducted at several sites in the midwestern United States where atrazine is commonly used, presents in situ observations of native algal communities relative to atrazine exposure and other parameters. Planktonic and periphytic algae from three streams in three Midwestern states, having historically differing atrazine levels, were sampled over a 16-week period in 2011 encompassing atrazine applications and the summer algal growth period at each site. Changes in abundance, diversity, and composition of algal communities were placed in the context of hydrological, climatic, and water quality parameters (including components sometimes present in agricultural runoff) also collected during the study. Diatoms dominated communities at each of the three sites and periphyton was much more abundant than phytoplankton. As expected, significant variations in algal community and environmental parameters were observed between sites. However, correspondence analysis plots revealed that patterns of temporal variation in algal communities at each site and in periphyton or phytoplankton were dominated by seasonal environmental gradients. Significant concordance in these seasonal patterns was detected among sites and between phytoplankton and periphyton communities (via procrustes Protest analysis), suggesting synchronicity of algal communities across a regional scale. While atrazine concentrations generally exhibited seasonal trends at the study watersheds; no effects on algal abundance, diversity or assemblage structure were observed as a result of atrazine pulses. This lack of response may be due to exposure events of insufficient concentration or duration (consistent with previously reported results) or

  7. Seasonal occurrence of antibiotics and a beta agonist in an agriculturally-intensive watershed.

    PubMed

    Jaimes-Correa, Juan C; Snow, Daniel D; Bartelt-Hunt, Shannon L

    2015-10-01

    We evaluated the occurrence of 12 veterinary antibiotics and a beta agonist over spatial and temporal scales in Shell Creek, an intensively agricultural watershed in Nebraska, using Polar Organic Chemical Integrative Samplers (POCIS). Twelve pharmaceuticals were detected with concentrations ranging from 0.0003 ng/L to 68 ng/L. The antibiotics measured at the highest time-weighted average concentrations were lincomycin (68 ng/L) and monensin (49 ng/L), and both compounds were detected at increased concentrations in summer months. Analysis of variance indicates that mean concentrations of detected pharmaceuticals have no significant (p > 0.01) spatial variation. However, significant temporal differences (p < 0.01) were observed. This study demonstrates the utility of passive samplers such as POCIS for monitoring ambient levels of pharmaceuticals in surface waters. PMID:26025261

  8. The contribution of soil biogenic NO and HONO emissions from a managed hyperarid ecosystem to the regional NOx emissions during growing season

    NASA Astrophysics Data System (ADS)

    Mamtimin, Buhalqem; Meixner, Franz X.; Behrendt, Thomas; Badawy, Moawad; Wagner, Thomas

    2016-08-01

    A study was carried out to understand the contributions of soil biogenic NO emissions from managed (fertilized and irrigated) hyperarid ecosystems in NW China to the regional NOx emissions during the growing season. Soil biogenic net potential NO fluxes were quantified by laboratory incubation of soil samples from the three dominating ecosystems (desert, cotton, and grape fields). Regional biogenic NO emissions were calculated bottom-up hourly for the entire growing season (April-September 2010) by considering corresponding land use, hourly data of soil temperature, gravimetric soil moisture, and fertilizer enhancement factors. The regional HONO emissions were estimated using the ratio of the optimum condition ((FN,opt(HONO) to FN,opt (NO)). Regional anthropogenic NOx emissions were calculated bottom-up from annual statistical data provided by regional and local government bureaus which have been downscaled to monthly value. Regional top-down emission estimates of NOx were derived on the monthly basis from satellite observations (OMI) of tropospheric vertical NO2 column densities and prescribed values of the tropospheric NOx lifetime. In order to compare the top-down and bottom-up emission estimates, all emission estimates were expressed in terms of mass of atomic nitrogen. Consequently, monthly top-down NOx emissions (total) were compared with monthly bottom-up NOx emissions (biogenic + anthropogenic) for the time of the satellite overpass (around 13:00 LT) with the consideration of the diurnal cycle of bottom-up estimates. Annual variation in total Tohsun Oasis NOx emissions is characterized by a strong peak in winter (December-February) and a secondary peak in summer (June-August). During summer, soil biogenic emissions were from equal to double that of related anthropogenic emissions, and grape soils were the main contributor to soil biogenic emissions, followed by cotton soils, while emissions from the desert were negligible. The top-down and bottom

  9. Deeper winter snow reduces ecosystem C losses but increases the global warming potential of Arctic tussock tundra over the growing season.

    NASA Astrophysics Data System (ADS)

    Blanc-Betes, E.; Welker, J. M.; Gomez-Casanovas, N.; Gonzalez-Meler, M. A.

    2015-12-01

    Arctic winter precipitation is projected to increase globally over the next decades, spatial variability encompassing areas with increases and decreases in winter snow. Changes in winter precipitation strongly affect C dynamics in Arctic systems and may lead to major positive climate forcing feedbacks. However, impacts of predicted changes in snowfall and accumulation on the rate and form of C fluxes (CO2 and CH4) and associated forcing feedbacks from Arctic tundra remain uncertain. We investigated how changes in winter precipitation affect net ecosystem CO2 and CH4 fluxes and budgets of moist acidic tundra in an 18-yrs snow fence experiment over a complete growing season at Toolik Lake, AK. Arctic tundra under ambient winter precipitation (CTL) was a net source of CO2 and CH4, yielding net C losses over the growing season. Reduced snow (-15-30% snow depth; RS) switched the system to a net CO2 sink mostly by limiting SOC decomposition within colder soils. Snow additions progressively reduced net ecosystem CO2 losses compared to CTL, switching the system into a weaker net CO2 source with medium additions (+20-45% snow depth; MS) and into a small net CO2 sink with high additions (+70-100% snow depth; HS). Increasingly wetter soils with snow additions constrained the temperature sensitivity of aerobic decomposition and favored the anaerobic metabolism, buffering ecosystem CO2 losses despite substantial soil warming. Accordingly, Arctic tundra switched from a sustained CH4 sink at RS site to an increasingly stronger CH4 source with snow additions. Accounting for both CO2 and CH4, the RS site became a net C sink over the growing season, overall reducing the global warming potential (CO2 equiv.; GWP) of the system relative to CTL. Snow additions progressively reduced net C losses at the MS site compared to CTL and the system transitioned into a net C sink at HS plots, partly due to the slower metabolism of anaerobic decomposition. However, given the greater radiative

  10. Isoprene Emissions from Downy Oak under Water Limitation during an Entire Growing Season: What Cost for Growth?

    PubMed Central

    Genard-Zielinski, Anne-Cyrielle; Ormeño, Elena; Boissard, Christophe; Fernandez, Catherine

    2014-01-01

    Increases in the production of terpene- and phenolic-like compounds in plant species under abiotic stress conditions have been interpreted in physiological studies as a supplementary defense system due to their capacity to limit cell oxidation. From an ecological perspective however, these increases are only expected to confer competitive advantages if they do not imply a significant cost for the plant, that is, growth reduction. We investigated shifts of isoprene emissions, and to a lesser extent phenolic compound concentration, of Quercus pubescens Willd. from early leaf development to leaf senescence under optimal watering (control: C), mild and severe water stress (MS, SS). The impact of water stress was concomitantly assessed on plant physiological (chlorophyll fluorescence, stomatal conductance, net photosynthesis, water potential) functional (relative leaf water content, leaf mass per area ratio) and growth (aerial and root biomass) traits. Growth changes allowed to estimate the eventual costs related to the production of isoprene and phenolics. The total phenolic content was not modified under water stress whereas isoprene emissions were promoted under MS over the entire growing cycle despite the decline of Pn by 35%. Under SS, isoprene emissions remained similar to C all over the study despite the decline of Pn by 47% and were thereby clearly uncoupled to Pn leading to an overestimation of the isoprene emission factor by 44%. Under SS, maintenance of isoprene emissions and phenolic compound concentration resulted in very significant costs for the plants as growth rates were very significantly reduced. Under MS, increases of isoprene emission and maintenance of phenolic compound concentration resulted in moderate growth reduction. Hence, it is likely that investment in isoprene emissions confers Q. pubescens an important competitive advantage during moderate but not severe periods of water scarcity. Consequences of this response for air quality in North

  11. Isoprene emissions from downy oak under water limitation during an entire growing season: what cost for growth?

    PubMed

    Genard-Zielinski, Anne-Cyrielle; Ormeño, Elena; Boissard, Christophe; Fernandez, Catherine

    2014-01-01

    Increases in the production of terpene- and phenolic-like compounds in plant species under abiotic stress conditions have been interpreted in physiological studies as a supplementary defense system due to their capacity to limit cell oxidation. From an ecological perspective however, these increases are only expected to confer competitive advantages if they do not imply a significant cost for the plant, that is, growth reduction. We investigated shifts of isoprene emissions, and to a lesser extent phenolic compound concentration, of Quercus pubescens Willd. from early leaf development to leaf senescence under optimal watering (control: C), mild and severe water stress (MS, SS). The impact of water stress was concomitantly assessed on plant physiological (chlorophyll fluorescence, stomatal conductance, net photosynthesis, water potential) functional (relative leaf water content, leaf mass per area ratio) and growth (aerial and root biomass) traits. Growth changes allowed to estimate the eventual costs related to the production of isoprene and phenolics. The total phenolic content was not modified under water stress whereas isoprene emissions were promoted under MS over the entire growing cycle despite the decline of Pn by 35%. Under SS, isoprene emissions remained similar to C all over the study despite the decline of Pn by 47% and were thereby clearly uncoupled to Pn leading to an overestimation of the isoprene emission factor by 44%. Under SS, maintenance of isoprene emissions and phenolic compound concentration resulted in very significant costs for the plants as growth rates were very significantly reduced. Under MS, increases of isoprene emission and maintenance of phenolic compound concentration resulted in moderate growth reduction. Hence, it is likely that investment in isoprene emissions confers Q. pubescens an important competitive advantage during moderate but not severe periods of water scarcity. Consequences of this response for air quality in North

  12. Seasonal OVOC fluxes from an agricultural field planted with sugar beet

    NASA Astrophysics Data System (ADS)

    Custer, T. G.; Schade, G. W.

    2005-12-01

    Although agricultural crops are generally not strong isoprenoid emitters, they do emit a variety of other atmospherically significant species collectively known as oxygenated VOCs (OVOCs), such as methanol, acetaldehyde, or various hexenal and hexenol compounds. Many OVOCs have longer atmospheric lifetimes than isoprenoid compounds and can affect the atmosphere's oxidative potential at higher elevations and far from sources. We performed selected OVOC flux measurements for select species above an agricultural field planted with sugar beets ( B. vulgaris) in northern Germany in 2004 to better understand the magnitude and controls over these OVOC emissions. Virtual disjunct eddy covariance was used to measure fluxes beginning immediately following seeding and continuing until past harvest. A commercial PTR-MS provided mixing ratios of methanol (m/z 33), acetaldehyde (m/z 45), acetone (m/z 59), and the sum of the isoprene oxidation products methacrolein and methyl vinyl ketone (m/z 71) while 3D wind velocities were measured using a Gill R3 sonic anemometer. Here, we compare the fluxes of methanol and acetone over the growth cycle of sugar beet to plant development as measured by the leaf area index. Methanol fluxes ranged from approximately -0.05 to 0.15 mg C m-2 h-1 (mixing ratios from ~1 to 15 ppbv) and showed a clear diurnal cycle after the sugar beets established a significant leaf area. Acetone fluxes ranged from approximately -0.2 to 0.2 mg C m-2 h-1 (mixing ratios from ~0.2 to 3 ppb). Higher specific emissions were found during earlier growth stages. Methanol flux correlated strongly with latent heat flux (or alternatively, with canopy conductance derived from the latent heat flux), while acetone flux did not. Acetone flux was small compared to methanol flux and sugar beet is likely not a significant acetone emitter. Weekly measurements of soil OVOC exchange using a flux chamber showed that the soil may have contributed significantly to the overall flux values

  13. Growing season fluxes and sources of CO2 and CH4 in high arctic ecosystems, NW Greenland

    NASA Astrophysics Data System (ADS)

    Lupascu, M.; Seibt, U.; Stills, A. K.; Xu, X.; Lindsey, D. S.; Welker, J. M.; Czimczik, C. I.

    2010-12-01

    Arctic tundra soils store vast amounts of organic carbon. Understanding how rapidly this pool can be mineralized as a consequence of warming and changes in the magnitude and timing of precipitation is a major uncertainty in predicting future levels of carbon dioxide in the atmosphere. We quantified the magnitudes and patterns of ecosystem-atmosphere fluxes of carbon dioxide (CO2) and methane (CH4) from polar semi-desert landscapes in NW Greenland. The measurements were undertaken from May to August 2010 at a multi-factorial, long-term climate change experiment started in 2003. In each treatment, fluxes were monitored from vegetated and barren soils. The experimental treatments consist of +2oC warming (T1), +4oC warming (T2), +50% summer precipitation (W), +4oC × +50% summer precipitation (T2W), and control (C). We used radiocarbon analysis to investigate the sources of carbon contributing to ecosystem carbon respiration under current and future climate conditions. Net ecosystem exchange (NEE) of CO2 and CH4 was measured continuously from four clear, automated chambers using cavity ring-down spectroscopy (Picarro 1301) under ambient and under conditions of high warming and added summer water (T2W). In all treatments, ecosystem respiration (R) from opaque chambers and soil pore space CO2 concentrations from soil wells were monitored daily via infrared spectroscopy (LI-COR 800 & 840) and sampled monthly for radiocarbon analysis. NEE fluxes were higher in vegetated than in bare soils and showed a clear seasonal pattern: both C and T2W treatments were a source of CO2 to the atmosphere in the spring and a net CO2 sink during summer. During the summer, NEE fluxes from vegetated soil were up to 5 times higher in the T2W (-11 µmol m-2 s-1) than ambient conditions (~ - 2 µmol m-2 s-1). Bare soils were a net source of CO2 at all times. All plots were a net sink of CH4 and showed a maximum in mid summer (-3 µmol m-2 s-1) when soil moisture was at a minimum. In the T2W

  14. Evaluation of growth potential of Crimean juniper (Juniperus excelsa Bieb.) seedlings for the first growing season under Tekir forest nursery conditions in Kahramanmaras, Turkey.

    PubMed

    Avsar, Mahmut D; Tonguc, Fatih

    2003-04-01

    In this study, growth potential of Crimean juniper (Juniperus excelsa Bieb.) seedlings for the first growing season under Tekir Forest Nursery conditions in Kahramanmaras was evaluated. The height growth of Crimean juniper seedlings was relatively close to that of Lebanon cedar (Cedrus libani A. Rich.) seedlings produced in the same nursery, but their root collar diameters were fairly lower than that of Lebanon cedar seedlings. According to coniferous seedling standards of Turkish Standards Institute, the height growth of Crimean juniper seedlings was fairly good, but their root collar diameters were slightly small. In this respect, that 2+0 or 1+1 Crimean juniper seedlings are used in reforestation activities in the region would be more useful than 1+0 seedlings. PMID:12974456

  15. A Satellite Based Modeling Framework for Estimating Seasonal Carbon Fluxes Over Agricultural Lands

    NASA Astrophysics Data System (ADS)

    Bandaru, V.; Houborg, R.; Izaurralde, R. C.

    2014-12-01

    Croplands are typically characterized by fine-scale heterogeneity, which makes it difficult to accurately estimate cropland carbon fluxes over large regions given the fairly coarse spatial resolution of high-frequency satellite observations. It is, however, important that we improve our ability to estimate spatially and temporally resolved carbon fluxes because croplands constitute a large land area and have a large impact on global carbon cycle. A Satellite based Dynamic Cropland Carbon (SDCC) modeling framework was developed to estimate spatially resolved crop specific daily carbon fluxes over large regions. This modeling framework uses the REGularized canopy reFLECtance (REGFLEC) model to estimate crop specific leaf area index (LAI) using downscaled MODIS reflectance data, and subsequently LAI estimates are integrated into the Environmental Policy Integrated Model (EPIC) model to determine daily net primary productivity (NPP) and net ecosystem productivity (NEP). Firstly, we evaluate the performance of this modeling framework over three eddy covariance flux tower sites (Bondville, IL; Fermi Agricultural Site, IL; and Rosemount site, MN). Daily NPP and NEP of corn and soybean crops are estimated (based on REGFLEC LAI) for year 2007 and 2008 over the flux tower sites and compared against flux tower observations and model estimates based on in-situ LAI. Secondly, we apply the SDCC framework for estimating regional NPP and NEP for corn, soybean and sorghum crops in Nebraska during year 2007 and 2008. The methods and results will be presented.

  16. A Satellite Based Modeling Framework for Estimating Seasonal Carbon Fluxes Over Agricultural Lands

    NASA Astrophysics Data System (ADS)

    Bandaru, V.; Izaurralde, R. C.; Sahajpal, R.; Houborg, R.; Milla, Z.

    2013-12-01

    Croplands are typically characterized by fine-scale heterogeneity, which makes it difficult to accurately estimate cropland carbon fluxes over large regions given the fairly coarse spatial resolution of high-frequency satellite observations. It is, however, important that we improve our ability to estimate spatially and temporally resolved carbon fluxes because croplands constitute a large land area and have a large impact on global carbon cycle. A Satellite based Dynamic Cropland Carbon (SDCC) modeling framework was developed to estimate spatially resolved crop specific daily carbon fluxes over large regions. This modeling framework uses the REGularized canopy reFLECtance (REGFLEC) model to estimate crop specific leaf area index (LAI) using downscaled MODIS reflectance data, and subsequently LAI estimates are integrated into the Environmental Policy Integrated Model (EPIC) model to determine daily net primary productivity (NPP) and net ecosystem productivity (NEP). Firstly, we evaluate the performance of this modeling framework over three eddy covariance flux tower sites (Bondville, IL; Fermi Agricultural Site, IL; and Rosemount site, MN). Daily NPP and NEP of corn and soybean crops are estimated (based on REGFLEC LAI) for year 2007 and 2008 over the flux tower sites and compared against flux tower observations and model estimates based on in-situ LAI. Secondly, we apply the SDCC framework for estimating regional NPP and NEP for corn, soybean and sorghum crops in Nebraska during year 2007 and 2008. The methods and results will be presented.

  17. Is health a labour, citizenship or human right? Mexican seasonal agricultural workers in Leamington, Canada.

    PubMed

    Barnes, Nielan

    2013-07-01

    Post-North American Free Trade Agreement (NAFTA) trade liberalisation combined with post-9/11 border securitisation means North America increasingly relies on pools of temporary foreign labour, particularly in the agricultural and service sectors. Despite being temporary, these workers often spend most of their years on foreign soil, living and working in isolated rural communities, far from their own families and communities. Migrants' mental and physical health suffers due to hazardous and stressful working conditions, sub-standard housing, lack of social support and limited access to health and social welfare services. Assuming access to health is a basic human right, who is responsible for the health of temporary foreign migrant workers? Is it the nation-state? or the Employers and/or unions? or Civil society? Research and practice show that a combined multisector approach is best; however, such initiatives are often uneven due to questions of sovereignty and citizenship rights. Community-based organisations (CBOs) have emerged to advocate for and serve migrants' social and welfare needs; analysis of CBO projects reveals an uneven application of rights to migrants. Using a comparative case study from Canada, this project contributes to understanding how civil-society helps to activate different types of health care rights for migrants, and to create an informed policy that provides migrant workers with access to a wider range of human and health rights. PMID:23672480

  18. Growing Season CO2-Net Ecosystem Exchange and CH4 Fluxes Response to Increase Precipitation in a Boreal Peatland, Eastmain Region, Quebec, Canada

    NASA Astrophysics Data System (ADS)

    Pelletier, L.; Garneau, M.

    2010-12-01

    Climate scenarios for northern Quebec, Canada, predict a rise in temperature of 3.9 to 4.5oC and an increase in precipitation of 3 to 7mm per month in a double CO2 climate. The response of Quebec’s James Bay peatlands to an increase in moisture/precipitation has not been thoroughly documented although these ecosystems are an important feature representing 30% of the landscape. Here we present results from three growing seasons of a study looking at CO2-net ecosystem exchange and CH4 fluxes to assess inter annual variability and the impact of greater precipitation on gas exchange. Monthly average temperatures between the studied growing seasons were within 1oC except in August 2008, which was 3oC warmer than previous years. Total precipitation was 30% greater between June and August 2008 than previous years. Results of CO2 exchange show significantly different relationships between photosynthetic photon flux density and NEE in 2008 on 3 of the 4 microforms studied as a result of increased precipitation. We found that when water table was closer to the surface productivity was increased on high and low hummocks through an increase in maximum rates of photosynthesis, and productivity was reduced on hollows through the flooding of the surface vegetation. Water table position was also a significant control on ecosystem respiration but only on the lawn microform. Elevated water table in 2008 had no significant effect on CH4 fluxes from the 4 microforms suggesting that reducing the oxidation layer thickness by 10cm does not influence fluxes at the surface. These results highlight the spatial and temporal variability in GHG fluxes from peatlands and the different responses of microforms to changing environmental conditions. The rapid response of vegetation productivity to the increase in precipitation in 2008 should also be considered for peat/carbon accumulation models.

  19. Changes in volatile emissions from apple trees and associated response of adult female codling moths over the fruit-growing season.

    PubMed

    Vallat, Armelle; Dorn, Silvia

    2005-05-18

    Odors in the headspace of apple trees were characterized by in situ volatile collections in the orchard. Sixty-two compounds were quantitatively identified with thermal desorption-gas chromatography-mass spectrometry over the complete fruit-growing season. Overall quantities in the headspace of fruit-bearing twig were highest at petal fall and at the beginning of June and August. Interestingly, the latter two periods coincide with the flight maxima of the codling moth, Cydia pomonella, one of the principal pest insects of apple fruit worldwide. Dual-choice bioassays with mated adult female moths in a Y-tube olfactometer showed that the blend of plant-derived volatiles repelled this key pest of apple at petal fall and attracted it from July to mid-August. Single-component analysis indicated that benzaldehyde and butyl acetate might contribute to the observed repellent effect, but the constituents accounting for the attractant effect mid-season remain to be further elucidated. The attractant effect clearly originates from the apple fruit and not from the twig with leaves, as bioassays demonstrated conclusively. PMID:15884843

  20. Beyond leaf color: Comparing camera-based phenological metrics with leaf biochemical, biophysical, and spectral properties throughout the growing season of a temperate deciduous forest

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Tang, Jianwu; Mustard, John F.

    2014-03-01

    Plant phenology, a sensitive indicator of climate change, influences vegetation-atmosphere interactions by changing the carbon and water cycles from local to global scales. Camera-based phenological observations of the color changes of the vegetation canopy throughout the growing season have become popular in recent years. However, the linkages between camera phenological metrics and leaf biochemical, biophysical, and spectral properties are elusive. We measured key leaf properties including chlorophyll concentration and leaf reflectance on a weekly basis from June to November 2011 in a white oak forest on the island of Martha's Vineyard, Massachusetts, USA. Concurrently, we used a digital camera to automatically acquire daily pictures of the tree canopies. We found that there was a mismatch between the camera-based phenological metric for the canopy greenness (green chromatic coordinate, gcc) and the total chlorophyll and carotenoids concentration and leaf mass per area during late spring/early summer. The seasonal peak of gcc is approximately 20 days earlier than the peak of the total chlorophyll concentration. During the fall, both canopy and leaf redness were significantly correlated with the vegetation index for anthocyanin concentration, opening a new window to quantify vegetation senescence remotely. Satellite- and camera-based vegetation indices agreed well, suggesting that camera-based observations can be used as the ground validation for satellites. Using the high-temporal resolution dataset of leaf biochemical, biophysical, and spectral properties, our results show the strengths and potential uncertainties to use canopy color as the proxy of ecosystem functioning.

  1. Ultra-high Resolution Carbon Isotope Records in Tree Rings: Indicators of Carbon Allocation and Growing Season Precipitation/Temperature (Invited)

    NASA Astrophysics Data System (ADS)

    Jahren, A.; Schubert, B.

    2010-12-01

    The rapidity and ease of carbon stable isotope measurements on organic substrates has opened the possibility of ultra-high resolution δ13C analyses within tree rings at < 30 to 100 micron increments. We present such measurements for 80 individual tree rings, from 10 trees spanning the last 55 million years in age from arctic, temperate, and tropical environments. Morphological features such as growth rings and resin canals were not preserved in some ancient specimens making identification of annual rings via standard techniques impossible. However, the annual patterns observed in ultra-high resolution δ13C records allowed for characterization of these unknown specimens as evergreen or deciduous. A combination of our data with that published in the literature showed a strong correlation between the amplitude of the δ13C pattern and growing season precipitation/temperature in > 90% of modern evergreen trees examined to date. Ultra-high resolution δ13C analyses of ancient, non-permineralized, evergreen trees could therefore provide quantitative estimates of past climate at annual or seasonal resolution.

  2. Impacts of Short-Rotation Early-Growing Season Prescribed Fire on a Ground Nesting Bird in the Central Hardwoods Region of North America

    PubMed Central

    2016-01-01

    Landscape-scale short-rotation early-growing season prescribed fire, hereafter prescribed fire, in upland hardwood forests represents a recent shift in management strategies across eastern upland forests. Not only does this strategy depart from dormant season to growing season prescriptions, but the strategy also moves from stand-scale to landscape-scale implementation (>1,000 ha). This being so, agencies are making considerable commitments in terms of time and resources to this management strategy, but the effects on wildlife in upland forests, especially those dominated by hardwood canopy species, are relatively unknown. We initiated our study to assess whether this management strategy affects eastern wild turkey reproductive ecology on the Ozark-St. Francis National Forest. We marked 67 wild turkey hens with Global Positioning System (GPS) Platform Transmitting Terminals in 2012 and 2013 to document exposure to prescribed fire, and estimate daily nest survival, nest success, and nest-site selection. We estimated these reproductive parameters in forest units managed with prescribed fire (treated) and units absent of prescribed fire (untreated). Of 60 initial nest attempts monitored, none were destroyed or exposed to prescribed fire because a majority of fires occurred early than a majority of the nesting activity. We found nest success was greater in untreated units than treated units (36.4% versus 14.6%). We did not find any habitat characteristic differences between successful and unsuccessful nest-sites. We found that nest-site selection criteria differed between treated and untreated units. Visual concealment and woody ground cover were common selection criteria in both treated and untreated units. However, in treated units wild turkey selected nest-sites with fewer small shrubs (<5 cm ground diameter) and large trees (>20 cm DBH) but not in untreated units. In untreated units wild turkey selected nest-sites with more large shrubs (≥5cm ground diameter) but

  3. Impacts of Short-Rotation Early-Growing Season Prescribed Fire on a Ground Nesting Bird in the Central Hardwoods Region of North America.

    PubMed

    Pittman, H Tyler; Krementz, David G

    2016-01-01

    Landscape-scale short-rotation early-growing season prescribed fire, hereafter prescribed fire, in upland hardwood forests represents a recent shift in management strategies across eastern upland forests. Not only does this strategy depart from dormant season to growing season prescriptions, but the strategy also moves from stand-scale to landscape-scale implementation (>1,000 ha). This being so, agencies are making considerable commitments in terms of time and resources to this management strategy, but the effects on wildlife in upland forests, especially those dominated by hardwood canopy species, are relatively unknown. We initiated our study to assess whether this management strategy affects eastern wild turkey reproductive ecology on the Ozark-St. Francis National Forest. We marked 67 wild turkey hens with Global Positioning System (GPS) Platform Transmitting Terminals in 2012 and 2013 to document exposure to prescribed fire, and estimate daily nest survival, nest success, and nest-site selection. We estimated these reproductive parameters in forest units managed with prescribed fire (treated) and units absent of prescribed fire (untreated). Of 60 initial nest attempts monitored, none were destroyed or exposed to prescribed fire because a majority of fires occurred early than a majority of the nesting activity. We found nest success was greater in untreated units than treated units (36.4% versus 14.6%). We did not find any habitat characteristic differences between successful and unsuccessful nest-sites. We found that nest-site selection criteria differed between treated and untreated units. Visual concealment and woody ground cover were common selection criteria in both treated and untreated units. However, in treated units wild turkey selected nest-sites with fewer small shrubs (<5 cm ground diameter) and large trees (>20 cm DBH) but not in untreated units. In untreated units wild turkey selected nest-sites with more large shrubs (≥5 cm ground diameter

  4. SUMMARY OF ACCOMPLISHMENTS AND DISAPPOINTMENTS, TUSKEGEE INSTITUTE-OEO SEASONALLY EMPLOYED AGRICULTURAL WORKERS EDUCATIONAL PROJECT, NOVEMBER 1, 1966-OCTOBER 31, 1967.

    ERIC Educational Resources Information Center

    PINNOCK, THEODORE J.; TAYLOR, G.W.

    THE SEASONALLY EMPLOYED AGRICULTURAL WORKERS PROGRAM WAS SPONSORED BY TUSKEGEE INSTITUTE, UNDER THE AUSPICES OF THE OFFICE OF ECONOMIC OPPORTUNITY, TO PROVIDE BASIC AND PREVOCATIONAL EDUCATION AND NEW GOALS FOR 1,239 FUNCTIONAL ILLITERATES, MOST OF THEM OWNERS OF SMALL FARMS, IN SEVEN ALABAMA COUNTIES. FAMILIES WERE HELPED TO IMPROVE THEIR…

  5. Spatio-temporal reconstruction of air temperature maps and their application to estimate rice growing season heat accumulation using multi-temporal MODIS data*

    PubMed Central

    Zhang, Li-wen; Huang, Jing-feng; Guo, Rui-fang; Li, Xin-xing; Sun, Wen-bo; Wang, Xiu-zhen

    2013-01-01

    The accumulation of thermal time usually represents the local heat resources to drive crop growth. Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity. To solve the critical problems of estimating air temperature (T a) and filling in missing pixels due to cloudy and low-quality images in growing degree days (GDDs) calculation from remotely sensed data, a novel spatio-temporal algorithm for T a estimation from Terra and Aqua moderate resolution imaging spectroradiometer (MODIS) data was proposed. This is a preliminary study to calculate heat accumulation, expressed in accumulative growing degree days (AGDDs) above 10 °C, from reconstructed T a based on MODIS land surface temperature (LST) data. The verification results of maximum T a, minimum T a, GDD, and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels. Overall, MODIS-derived AGDD was slightly underestimated with almost 10% relative error. However, the feasibility of employing AGDD anomaly maps to characterize the 2001–2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper. Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring, agricultural climatic regionalization, and agro-meteorological disaster detection at the regional scale. PMID:23365013

  6. Spatio-temporal reconstruction of air temperature maps and their application to estimate rice growing season heat accumulation using multi-temporal MODIS data.

    PubMed

    Zhang, Li-wen; Huang, Jing-feng; Guo, Rui-fang; Li, Xin-xing; Sun, Wen-bo; Wang, Xiu-zhen

    2013-02-01

    The accumulation of thermal time usually represents the local heat resources to drive crop growth. Maps of temperature-based agro-meteorological indices are commonly generated by the spatial interpolation of data collected from meteorological stations with coarse geographic continuity. To solve the critical problems of estimating air temperature (T(a)) and filling in missing pixels due to cloudy and low-quality images in growing degree days (GDDs) calculation from remotely sensed data, a novel spatio-temporal algorithm for T(a) estimation from Terra and Aqua moderate resolution imaging spectroradiometer (MODIS) data was proposed. This is a preliminary study to calculate heat accumulation, expressed in accumulative growing degree days (AGDDs) above 10 °C, from reconstructed T(a) based on MODIS land surface temperature (LST) data. The verification results of maximum T(a), minimum T(a), GDD, and AGDD from MODIS-derived data to meteorological calculation were all satisfied with high correlations over 0.01 significant levels. Overall, MODIS-derived AGDD was slightly underestimated with almost 10% relative error. However, the feasibility of employing AGDD anomaly maps to characterize the 2001-2010 spatio-temporal variability of heat accumulation and estimating the 2011 heat accumulation distribution using only MODIS data was finally demonstrated in the current paper. Our study may supply a novel way to calculate AGDD in heat-related study concerning crop growth monitoring, agricultural climatic regionalization, and agro-meteorological disaster detection at the regional scale. PMID:23365013

  7. Nesting Biology and Fungiculture of the Fungus-Growing Ant, Mycetagroicus cerradensis: New Light on the Origin of Higher Attine Agriculture

    PubMed Central

    Solomon, Scott E.; Lopes, Cauê T.; Mueller, Ulrich G.; Rodrigues, Andre; Sosa-Calvo, Jeffrey; Schultz, Ted R.; Vasconcelos, Heraldo L.

    2011-01-01

    The genus Mycetagroicus is perhaps the least known of all fungus-growing ant genera, having been first described in 2001 from museum specimens. A recent molecular phylogenetic analysis of the fungus-growing ants demonstrated that Mycetagroicus is the sister to all higher attine ants (Trachymyrmex, Sericomyrmex, Acromyrmex, Pseudoatta, and Atta), making it of extreme importance for understanding the transition between lower and higher attine agriculture. Four nests of Mycetagroicus cerradensis near Uberlândia, Minas Gerais, Brazil were excavated, and fungus chambers for one were located at a depth of 3.5 meters. Based on its lack of gongylidia (hyphal-tip swellings typical of higher attine cultivars), and a phylogenetic analysis of the ITS rDNA gene region, M. cerradensis cultivates a lower attine fungus in Clade 2 of lower attine (G3) fungi. This finding refines a previous estimate for the origin of higher attine agriculture, an event that can now be dated at approximately 21–25 mya in the ancestor of extant species of Trachymyrmex and Sericomyrmex. PMID:21526926

  8. Effects of co-cropping Bidens pilosa (L.) and Tagetes minuta (L.) on bioaccumulation of Pb in Lactuca sativa (L.) growing in polluted agricultural soils.

    PubMed

    Cid, Carolina Vergara; Rodriguez, Judith Hebelen; Salazar, María Julieta; Blanco, Andrés; Pignata, María Luisa

    2016-09-01

    Polluted agricultural soils are a serious problem for food safety, with phytoremediation being the most favorable alternative from the environmental perspective. However, this methodology is generally time-consuming and requires the cessation of agriculture. Therefore, the purpose of this study was to evaluate two potential phytoextractor plants (the native species Bidens pilosa and Tagetes minuta) co-cropped with lettuce growing on agricultural lead-polluted soils. The concentrations of Pb, as well as of other metals, were investigated in the phytoextractors, crop species, and in soils, with the potential risk to the health of consumers being estimated. The soil parameters pH, EC, organic matter percentage and bioavailable lead showed a direct relationship with the accumulation of Pb in roots. In addition, the concentration of Pb in roots of native species was closely related to Fe (B. pilosa, r = 0.81; T. minuta r = 0.75), Cu (T. minuta, r = 0.93), Mn (B. pilosa, r = 0.89) and Zn (B. pilosa, r = 0.91; T. minuta, r = 0.91). Our results indicate that the interaction between rhizospheres increased the phytoextraction of lead, which was accompanied by an increase in the biomass of the phytoextractor species. However, the consumption of lettuce still revealed a toxicological risk from Pb in all treatments. PMID:26940382

  9. Identifying the spatial and temporal variability of economic opportunity costs to promote the adoption of alternative land uses in grain growing agricultural areas: an Australian example.

    PubMed

    Lyle, G; Bryan, B A; Ostendorf, B

    2015-05-15

    Grain growers face many future challenges requiring them to adapt their land uses to changing economic, social and environmental conditions. To understand where to make on ground changes without significant negative financial repercussions, high resolution information on income generation over time is required. We propose a methodology which utilises high resolution yield data collected with precision agriculture (PA) technology, gross margin financial analysis and a temporal standardisation technique to highlight the spatial and temporal consistency of farm income. On three neighbouring farms in Western Australia, we found non-linear relationships between income and area. Spatio-temporal analysis on one farm over varying seasons found that between 37 and 49% (1082-1433ha) of cropping area consistently produced above the selected income thresholds and 43-32% (936-1257ha) regularly produced below selected thresholds. Around 20% of area showed inconsistent temporal variation in income generation. Income estimated from these areas represents the income forgone if a land use change is undertaken (the economic opportunity cost) and the average costs varied spatially from $190±114/ha to $560±108/ha depending on what scenario was chosen. The interaction over space and time showed the clustering of areas with similar values at a resolution where growers make input decisions. This new evidence suggests that farm area could be managed with two strategies: (a) one that maximises grain output using PA management in temporally stable areas which generate moderate to high income returns and (b) one that proposes land use change in low and inconsistent income returning areas where the financial returns from an alternative land use may be comparable. The adoption of these strategies can help growers meet the demand for agricultural output and offer income diversity and adaptive capacity to deal with the future challenges to agricultural production. PMID:25836353

  10. Hydroclimatic Controls on the Seasonal and Inter-Annual Variability of Dissolved Phosphorus Concentration in a Lowland Agricultural Catchment

    NASA Astrophysics Data System (ADS)

    Dupas, R.; Gascuel-odoux, C.; Grimaldi, C.; Gruau, G.

    2014-12-01

    We investigated soluble reactive phosphorus (SRP) at the outlet of a lowland agricultural catchment (Kervidy-Naizin, France) to identify the hydroclimatic controls on the seasonal and inter-annual variability in concentrations. Six years of stream data have been used, including a regular 6-daily sampling and high-frequency monitoring of 52 floods. Both on an annual basis and during flood events, distinct export dynamics for SRP and particulate phosphorus (PP) revealed that SRP transport mechanism was independent from PP (Dupas et al., submitted). During most flood events, discharge-SRP hystereses were anticlockwise, which suggests that SRP was transferred to the stream via subsurface flow. Groundwater rise in wetland soils was likely the cause of this transfer, through the hydrological connectivity it created between the stream and P-rich soil horizons. SRP concentrations were highest in the beginning of the hydrological year (period A), when the stream started to flow again after the dry summer season and water table fluctuated in the wetland domain. Thus, wetland soils seemed to be a major source of SRP. Concentrations during period A were higher after a long summer period than after a short one, which suggest that a pool of labile P was constituted in soils during the dry summer period. During winter (period B), SRP concentration generally decreased compared to period A, both during floods and interflood. This could be due to depletion of a soil P pool in the wetland domain and/or dilution by deep groundwater with low P concentration from the upland domain. Concentration during period B barely decreased compared to A during wet years, probably due to increased connectivity with soils from the upland domain in wet conditions. During spring (period C), SRP concentration increased during baseflow periods. The possible mechanisms causing the release of SRP could involve reduction of Fe oxide-hydroxides in wetland soils or in-stream processes. At the same time, SRP

  11. Vertical distribution of heavy metals in soil profile in a seasonally waterlogging agriculture field in Eastern Ganges Basin.

    PubMed

    Rajmohan, N; Prathapar, S A; Jayaprakash, M; Nagarajan, R

    2014-09-01

    The accumulation of heavy metals in soil and water is a serious concern due to their persistence and toxicity. This study investigated the vertical distribution of heavy metals, possible sources and their relation with soil texture in a soil profile from seasonally waterlogged agriculture fields of Eastern Ganges basin. Fifteen samples were collected at ~0.90-m interval during drilling of 13.11 mbgl and analysed for physical parameters (moisture content and grain size parameters: sand, silt, clay ratio) and heavy metals (Fe, Mn, Cr, Cu, Pb, Zn, Co, Ni and Cd). The average metal content was in the decreasing order of Fe > Mn > Cr > Zn > Ni > Cu > Co > Pb > Cd. Vertical distribution of Fe, Mn, Zn and Ni shows more or less similar trends, and clay zone records high concentration of heavy metals. The enrichment of heavy metals in clay zone with alkaline pH strongly implies that the heavy metal distributions in the study site are effectively regulated by soil texture and reductive dissolution of Fe and Mn oxy-hydroxides. Correlation coefficient analysis indicates that most of the metals correlate with Fe, Mn and soil texture (clay and silt). Soil quality assessment was carried out using geoaccumulation index (I(geo)), enrichment factor (EF) and contamination factor (CF). The enrichment factor values were ranged between 0.66 (Mn) and 2.34 (Co) for the studied metals, and the contamination factor values varied between 0.79 (Mn) and 2.55 (Co). Results suggest that the elements such as Cu and Co are categorized as moderate to moderately severe contamination, which are further confirmed by I(geo) values (0.69 for Cu and 0.78 for Co). The concentration of Ni exceeded the effects-range median values, and the biological adverse effect of this metal is 87%. The average concentration of heavy metals was compared with published data such as concentration of heavy metals in Ganga River sediments, Ganga Delta sediments and upper continental crust (UCC

  12. Nitrogen Cycle Modeling: a Mechanistic Estimate of N-losses From Agricultural Fields Over the Seasonal Time Period

    NASA Astrophysics Data System (ADS)

    Maggi, F.; Gu, C.; Venterea, R.; Riley, W.; Oldenburg, C.

    2007-12-01

    The biogeochemical cycle of nitrogen and production of NO, N2O, and CO2 gas and NO2- and NO3- ions in nutrient-enriched agricultural fields is mediated by soil microbial activity, the hydrological cycle, plant dynamics, and climatic forcing. Understanding how NO, N2O, CO2 gases and NO2- and NO3- ions are released from agricultural fields to the environment is a key factor in controlling the green-house effect and water contamination, and assumes ever greater importance in view of the foreseen increase in biofuel, food, and fiber production. To address these issues we have developed a mechanistic model (TOUGHREACT-N) for various nitrification and denitrification pathways, multiple microbial biomass dynamics, heat and water flows, and various chemical reactions at local and kinetic equilibrium. The soil column is represented in a 1D framework, with hydraulic properties described by a water tension-saturation model. Biotic and abiotic reactions are assumed to follow Michaelis-Menten kinetics, while a consortium of several micro-organismal strains is assumed to follow multiple Monod growth kinetics accounting for electron donor, electron acceptor, and inhibitor concentrations. Water flow is modeled with the Darcy-Richards equation, while nutrient transport is modeled by Fickian advective and diffusive processes in both gaseous and liquid phases. Heat flow is modeled with the Fourier equation. Plant dynamics is taken into account by coupling TOUGHREACT-N with CERES to determine water and nutrient uptake, and soil carbon accumulation. TOUGHREACT-N was calibrated against field measurements to assess pathways of N losses following fertilization. A good agreement between field observations and model predictions was found. We identified two dominant time scales in the system response that depended on plants dynamics. Before plants have substantial impact on soil nutrients and moisture content, N losses are characterized by rapid increases as a function of water application

  13. Growing season variability of net ecosystem CO2 exchange and evapotranspiration of a sphagnum mire in the broad-leaved forest zone of European Russia

    NASA Astrophysics Data System (ADS)

    Olchev, A.; Volkova, E.; Karataeva, T.; Novenko, E.

    2013-09-01

    The spatial and temporal variability of net ecosystem exchange (NEE) of CO2 and evapotranspiration (ET) of a karst-hole sphagnum peat mire situated at the boundary between broad-leaved and forest-steppe zones in the central part of European Russia in the Tula region was described using results from field measurements. NEE and ET were measured using a portable measuring system consisting of a transparent ventilated chamber combined with an infrared CO2/H2O analyzer, LI-840A (Li-Cor, USA) along a transect from the southern peripheral part of the mire to its center under sunny clear-sky weather conditions in the period from May to September of 2012 and in May 2013. The results of the field measurements showed significant spatial and temporal variability of NEE and ET that was mainly influenced by incoming solar radiation and ground water level. The seasonal patterns of NEE and ET within the mire were quite different. During the entire growing season the central part of the mire was a sink of CO2 for the atmosphere. NEE reached maximal values in June-July (-6.8 ± 4.2 μmol m-2 s-1). The southern peripheral part of the mire, due to strong shading by the surrounding forest, was a sink of CO2 for the atmosphere in June-July only. ET reached maximal values in the well-lighted central parts of the mire in May (0.34 ± 0.20 mm h-1) mainly because of high air and surface temperatures and the very wet upper peat horizon and sphagnum moss. Herbaceous species made the maximum contribution to the total gross primary production (GPP) in both the central and the peripheral parts of the mire. The contribution of sphagnum to the total GPP of these plant communities was relatively small and ranged on sunny days of July-August from -1.1 ± 1.1 mgC g-1 of dry weight (DW) per hour in the peripheral zone of the mire to -0.6 ± 0.2 mgC g-1 DW h-1 at the mire center. The sphagnum layer made the maximum contribution to total ET at the mire center (0.25 ± 0.10 mm h-1) and the herbaceous

  14. Rate of Nitrogen Application during the Growing Season and Spraying Plants with Urea in the Autumn Alters Uptake of other Nutrients by Deciduous and Evergreen Container-Grown Rhododendron

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of N rate during the growing season and spraying plants with urea in the autumn on the uptake of other nutrients was assessed using container-grown rhododendron (Rhododendron 'H-1 P.J.M') and azalea (Rhododendron 'Cannon’s Double'). Plants were grown with a complete fertilizer containi...

  15. Projections of the advance in the start of the growing season during the 21st century based on CMIP5 simulations

    NASA Astrophysics Data System (ADS)

    Xia, Jiangjiang; Yan, Zhongwei; Jia, Gensuo; Zeng, Heqing; Jones, Philip Douglas; Zhou, Wen; Zhang, Anzhi

    2015-06-01

    It is well-known that global warming due to anthropogenic atmospheric greenhouse effects advanced the start of the vegetation growing season (SOS) across the globe during the 20th century. Projections of further changes in the SOS for the 21st century under certain emissions scenarios (Representative Concentration Pathways, RCPs) are useful for improving understanding of the consequences of global warming. In this study, we first evaluate a linear relationship between the SOS (defined using the normalized difference vegetation index) and the April temperature for most land areas of the Northern Hemisphere for 1982-2008. Based on this relationship and the ensemble projection of April temperature under RCPs from the latest state-of-the-art global coupled climate models, we show the possible changes in the SOS for most of the land areas of the Northern Hemisphere during the 21st century. By around 2040-59, the SOS will have advanced by -4.7 days under RCP2.6, -8.4 days under RCP4.5, and -10.1 days under RCP8.5, relative to 1985-2004. By 2080-99, it will have advanced by -4.3 days under RCP2.6, -11.3 days under RCP4.5, and -21.6 days under RCP8.5. The geographic pattern of SOS advance is considerably dependent on that of the temperature sensitivity of the SOS. The larger the temperature sensitivity, the larger the date-shift-rate of the SOS.

  16. Fusarium species and fumonisins associated with maize kernels produced in Rio Grande do Sul State for the 2008/09 and 2009/10 growing seasons

    PubMed Central

    Stumpf, R.; dos Santos, J.; Gomes, L.B.; Silva, C.N.; Tessmann, D.J.; Ferreira, F.D.; Machinski, M.; Del Ponte, E.M.

    2013-01-01

    Ear rots caused by Fusarium spp. are among the main fungal diseases that contribute to poor quality and the contamination of maize grains with mycotoxins. This study aimed to determine the visual incidence of fungal-damaged kernels (FDKs), the incidence of two main Gibberella (a teleomorph of Fusarium) complexes (G. fujikuroi and G. zeae) associated with maize using a seed health blotter test, and the fumonisin levels, using high performance liquid chromatography, in samples of maize grains grown across 23 municipalities during the 2008/09 and 2009/10 growing seasons. Additionally, 104 strains that were representative of all of the analysed samples were identified to species using PCR assays. The mean FDK was seven per cent, and only six of the samples had levels greater than six per cent. Fusarium spp. of the G. fujikuroi complex were present in 96% of the samples, and G. zeae was present in 18% of the samples (5/27). The mean incidence of G. fujikuroi was 58%, and the incidence of G. zeae varied from 2 to 6%. FB1 was found in 58.6%, FB2 in 37.9%, and both toxins in 37.9% of the samples. The FB1 and FB2 levels were below the quantification limits for 41.3% of the samples, and the mean FB1 levels (0.66 μg/g) were higher than the mean FB2 levels (0.42 μg/g). The PCR identification separated the 104 isolates into three of the G. fujikuroi complex: F. verticillioides (76%), F. subglutinans (4%) and F. proliferatum (2%); and G. zeae (anamorph = F. graminearum) (18%). Our results confirmed the dominance of F. verticillioides, similar to other regions of Brazil, but they differed due to the relatively higher incidence of F. graminearum. Total fumonisin levels were below the maximum limit determined by current Brazilian regulations. PMID:24159288

  17. Fusarium species and fumonisins associated with maize kernels produced in Rio Grande do Sul State for the 2008/09 and 2009/10 growing seasons.

    PubMed

    Stumpf, R; Dos Santos, J; Gomes, L B; Silva, C N; Tessmann, D J; Ferreira, F D; Machinski, M; Del Ponte, E M

    2013-01-01

    Ear rots caused by Fusarium spp. are among the main fungal diseases that contribute to poor quality and the contamination of maize grains with mycotoxins. This study aimed to determine the visual incidence of fungal-damaged kernels (FDKs), the incidence of two main Gibberella (a teleomorph of Fusarium) complexes (G. fujikuroi and G. zeae) associated with maize using a seed health blotter test, and the fumonisin levels, using high performance liquid chromatography, in samples of maize grains grown across 23 municipalities during the 2008/09 and 2009/10 growing seasons. Additionally, 104 strains that were representative of all of the analysed samples were identified to species using PCR assays. The mean FDK was seven per cent, and only six of the samples had levels greater than six per cent. Fusarium spp. of the G. fujikuroi complex were present in 96% of the samples, and G. zeae was present in 18% of the samples (5/27). The mean incidence of G. fujikuroi was 58%, and the incidence of G. zeae varied from 2 to 6%. FB1 was found in 58.6%, FB2 in 37.9%, and both toxins in 37.9% of the samples. The FB1 and FB2 levels were below the quantification limits for 41.3% of the samples, and the mean FB1 levels (0.66 μg/g) were higher than the mean FB2 levels (0.42 μg/g). The PCR identification separated the 104 isolates into three of the G. fujikuroi complex: F. verticillioides (76%), F. subglutinans (4%) and F. proliferatum (2%); and G. zeae (anamorph = F. graminearum) (18%). Our results confirmed the dominance of F. verticillioides, similar to other regions of Brazil, but they differed due to the relatively higher incidence of F. graminearum. Total fumonisin levels were below the maximum limit determined by current Brazilian regulations. PMID:24159288

  18. The impact of growing-season length variability on carbon assimilation and evapotranspiration over 88 years in the eastern US deciduous forest

    PubMed

    White; Running; Thornton

    1999-02-01

    Recent research suggests that increases in growing-season length (GSL) in mid-northern latitudes may be partially responsible for increased forest growth and carbon sequestration. We used the BIOME-BGC ecosystem model to investigate the impacts of including a dynamically regulated GSL on simulated carbon and water balance over a historical 88-year record (1900-1987) for 12 sites in the eastern USA deciduous broadleaf forest. For individual sites, the predicted GSL regularly varied by more than 15 days. When grouped into three climatic zones, GSL variability was still large and rapid. There is a recent trend in colder, northern sites toward a longer GSL, but not in moderate and warm climates. The results show that, for all sites, prediction of a long GSL versus using the mean GSL increased net ecosystem production (NEP), gross primary production (GPP), and evapotranspiration (ET); conversely a short GSL is predicted to decrease these parameters. On an absolute basis, differences in GPP between the dynamic and mean GSL simulations were larger than the differences in NEP. As a percentage difference, though, NEP was much more sensitive to changes in GSL than were either GPP or ET. On average, a 1-day change in GSL changed NEP by 1.6%, GPP by 0.5%, and ET by 0.2%. Predictions of NEP and GPP in cold climates were more sensitive to changes in GSL than were predictions in warm climates. ET was not similarly sensitive. First, our results strongly agree with field measurements showing a high correlation between NEP and dates of spring growth, and second they suggest that persistent increases in GSL may lead to long-term increases in carbon storage. PMID:10083835

  19. Chemical characteristics and source apportionment of PM2.5 during the harvest season in eastern China's agricultural regions

    NASA Astrophysics Data System (ADS)

    Li, Jianfeng; Song, Yu; Mao, Yi; Mao, Zhichun; Wu, Yusheng; Li, Mengmeng; Huang, Xin; He, Qichao; Hu, Min

    2014-08-01

    To determine the contribution of the open burning of wheat straw residues to local PM2.5 during the harvest season of June 2013, PM2.5 was sampled in an agricultural region in eastern China. The sampling site was approximately 1 km from the nearest wheat field. Chemical compositions were analyzed, and source apportionment was undertaken using the positive matrix factorization model. The average PM2.5 concentration was 110.7 μg/m3, containing 36.4 μg/m3 organics, 7.3 μg/m3 EC, 6.0 μg/m3 potassium (K) and 4.9 μg/m3 chloride ion (Cl-). The sampling period was divided into three phases: the pre-local-burning phase (Phase 1), the local-burning phase (Phase 2) and the post-local-burning phase (Phase 3). In Phase 2, the concentrations of PM2.5 and the organics, EC, K and Cl- in PM2.5 were 163.6 μg/m3, 59.0 μg/m3, 12.2 μg/m3, 11.0 μg/m3 and 10.8 μg/m3, respectively, which were all remarkably higher than in both Phase 1 and Phase 3. Eight sources of PM2.5 were determined, including two types of wheat residue burning sources, which showed a significant difference in Cl- content. The atmospheric relative humidity (RH) and the aging process of PM2.5 might be the causes: only fresh particulate emissions from wheat residue burning could feature high-concentration Cl- under high RH conditions. In Phase 2, wheat residue burning contributed 51.3% of PM2.5, 75.8% of OC, 74.5% of EC, 90.1% of K and 104.1% of Cl-. These percentages were lower in Phases 1 and 3 than in Phase 2. Wheat residue burning caused such severe air pollution that it's necessary to prohibit the open burning of crop residues in order to protect public health and the environment.

  20. Investigating the implications of meteorological indicators of seasonal rainfall performance on maize yield in a rain-fed agricultural system: case study of Mt. Darwin District in Zimbabwe

    NASA Astrophysics Data System (ADS)

    Mushore, Terence; Manatsa, Desmond; Pedzisai, Ezra; Muzenda-Mudavanhu, Chipo; Mushore, Washington; Kudzotsa, Innocent

    2016-06-01

    The study focuses on the impacts of climate variability and change on maize yield in Mt. Darwin District. The rainfall and temperature data for the period under study that is from 1992 to 2012 were obtained from Meteorological Services Department of Zimbabwe at daily resolution while crop yield data were obtained from Department of Agricultural, Technical and Extension Services (AGRITEX) and Zimbabwe Statistics Agency (ZIMSTAT) at seasonal/yearly resolution. In order to capture full rainfall seasons, a year was set to begin on 1 June and end on 31 July the next year. Yearly yield, temperature and rainfall data were used to compute time series analysis of rainfall, temperature and yield. The relationship between temperature, rainfall, quality of season (start, cessation, dry days, wet days and length) and yield was also investigated. The study also investigated the link between meteorological normal and maize yield. The study revealed that temperature is rising while rainfall is decreasing with time hence increasing risk of low maize yield in Mt. Darwin. Correlation between maize yield was higher using a non-linear (R 2 = 0.630) than a linear regression model (R 2 = 0.173). There was a very high correlation between maize yield and number of dry days (R = -0.905) as well as between maize yield and length of season (R = 0.777). We also observed a strong correlation between percentage normal rainfall and percentage normal maize yield (R 2 = 0.753). This was also agreed between rainfall tessiles and maize yield tessiles as 50 % of the seasons had normal and above normal rainfall coinciding with normal and above normal maize yield. Of the 21 seasons considered, only one season had above normal rainfall while maize yield was below normal. The study concluded that there is a strong association between meteorological normal and maize yield in a rain-fed agricultural system. Climate information remains crucial to agricultural productivity hence the need to train farmers to

  1. Genetic diversity and insecticide resistance during the growing season in the green peach aphid (Hemiptera: Aphididae) on primary and secondary hosts: a farm-scale study in Central Chile.

    PubMed

    Rubiano-Rodríguez, J A; Fuentes-Contreras, E; Figueroa, C C; Margaritopoulos, J T; Briones, L M; Ramírez, C C

    2014-04-01

    The seasonal dynamics of neutral genetic diversity and the insecticide resistance mechanisms of insect pests at the farm scale are still poorly documented. Here this was addressed in the green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) in Central Chile. Samples were collected from an insecticide sprayed peach (Prunus persica L.) orchard (primary host), and a sweet-pepper (Capsicum annum var. grossum L.) field (secondary host). In addition, aphids from weeds (secondary hosts) growing among these crops were also sampled. Many unique multilocus genotypes were found on peach trees, while secondary hosts were colonized mostly by the six most common genotypes, which were predominantly sensitive to insecticides. In both fields, a small but significant genetic differentiation was found between aphids on the crops vs. their weeds. Within-season comparisons showed genetic differentiation between early and late season samples from peach, as well as for weeds in the peach orchard. The knock-down resistance (kdr) mutation was detected mostly in the heterozygote state, often associated with modified acetylcholinesterase throughout the season for both crops. This mutation was found in high frequency, mainly in the peach orchard. The super-kdr mutation was found in very low frequencies in both crops. This study provides farm-scale evidence that the aphid M. persicae can be composed of slightly different genetic groups between contiguous populations of primary and secondary hosts exhibiting different dynamics of insecticide resistance through the growing season. PMID:24484894

  2. The ever-increasing CO2 seasonal cycle amplitude: contributions from high latitude warming, CO2 fertilization, and the agricultural Green Revolution

    NASA Astrophysics Data System (ADS)

    Zeng, N.; Martin, C.; Zhao, F.; Collatz, G. J.; Kalnay, E.; Salawitch, R. J.; West, T. O.; Guanter, L.

    2014-12-01

    Human activities has tranformed the Earth's surface in complex ways. Here we show that not only land cover change, but also the management intensity, namely the intensification of agriculture through the Green Revolution has had a profound impact on the carbon cycle. A long-standing puzzle in the global carbon cycle is the increase in the amplitude of the seasonal cycle of atmospheric CO2. This increase likely reflects enhanced biological activity in the Northern Hemisphere (NH). It has been hypothesized that vegetation growth may have been stimulated by higher concentrations of CO2 as well as warming in recent decades, but the role of such specific mechanisms has not been quantified and they have been unable to explain the full range and magnitude of observations. Here we suggest another potential driver of the increased seasonal amplitude: the intensification of agriculture from the Green Revolution to feed a rising population, that led to a 3-fold increase in world crop production over the last 5 decades. Our analysis of CO2 data and atmospheric inversions shows a robust 15% long-term increase in CO2 seasonal amplitude from 1961 to 2010 that is punctuated by large decadal and interannual variations. The three pillars of the Green Revolution, consisting of high yield cultivars, fertilizer use, and irrigation, are represented in a terrestrial carbon cycle model. The results reveal that the long-term increase in CO2 seasonal amplitude arises from two major regions in the NH: the mid-latitude cropland between 25N-60N that encompasses the world's major agriculture zones in Asia, Europe and North America, and the high-latitude natural vegetation between 50N-70N that includes much of the Northern boreal forests, tundra and some deciduous forests. The long-term trend of seasonal amplitude is 0.3% per year, of which sensitivity experiments attribute 43% to land use change, 31% to climate variability and change, and 26% to CO2 fertilization. Our results suggest that human

  3. SPATIAL AND TEMPORAL PATTERNS OF THE MOVEMENT OF SEASONAL AGRICULTURAL MIGRANT CHILDREN INTO WISCONSIN, EDUCATIONAL PROGRAMS FOR CHILDREN OF MIGRATORY AGRICULTURAL WORKERS IN WISCONSIN, REPORT 2.

    ERIC Educational Resources Information Center

    LINDSEY, HERBERT H.; AND OTHERS

    USEFUL MEANS OF ANTICIPATING THE MOVEMENTS OF MIGRANT CHILDREN INCLUDE ANALYSIS OF CROPS, THE HARVESTING OF WHICH REQUIRES OUT-OF-STATE WORKERS, DISTRIBUTIONAL MAPS OF CROP ACREAGE, NORMAL TIME SCHEDULES FOR CROPS, AND INFORMATION ON AGRICULTURAL DEVELOPMENTS. SUCH INFORMATION ASSISTS IN THE PLANNING OF SCHOOL PROGRAMS. IN WISCONSIN, MOST MIGRANT…

  4. Seasonal dynamics in photosynthesis of woody plants at the northern limit of Asian tropics: potential role of fog in maintaining tropical rainforests and agriculture in Southwest China.

    PubMed

    Zhang, Yong-Jiang; Holbrook, N Michele; Cao, Kun-Fang

    2014-10-01

    The lowland tropical rainforests in Xishuangbanna, Southwest (SW) China, mark the northern limit of Asian tropics. Fog has been hypothesized to play a role in maintaining rainforests and tropical crop production in this region, but the physiological mechanism has not been studied. The goals of this study were to characterize the seasonal dynamics in photosynthesis and to assess the potential for fog to mitigate chilling-induced photodamage for tropical trees and crops in Xishuangbanna. We measured seasonal dynamics in light-saturated net photosynthetic rate (Aa), stomatal conductance (gs), intercellular CO2 concentration, quantum yield of Photosystem II (Fv/Fm) and maximum P700 changes (Pm; indicates the amount of active PSI complex), as well as chilling resistance and fog (light/shading) effects on low temperature-induced decline in Fv/Fm and Pm for native tree and introduced lower latitude tree or woody shrub species grown in a tropical botanical garden. Despite significant decreases in Aa, gs, Pm and Fv/Fm, most species maintained considerably high Aa during the cool season (2.51-14.6 μmol m(-2) s(-1)). Shaded leaves exposed to seasonal low temperatures had higher Fv/Fm than sun-exposed leaves in the cool season. All species could tolerate 1.4 °C in the dark, whereas a combined treatment of low temperature and high light caused a distinctly faster decline in Pm and Fv/Fm compared with low temperature treatment alone. Because fog persistence avoids or shortens the duration of high light condition in the morning when the temperatures are still low, our results provide support for the hypothesis that fog reduces chilling damage to tropical plants in this region and thus plays a role in maintaining tropical rainforests and agriculture in SW China. PMID:25298374

  5. Climate Variability is Influencing Agricultural Expansion and Output in a Key Agricultural Region of Brazil

    NASA Astrophysics Data System (ADS)

    Spera, S. A.; Cohn, A.; VanWey, L.; Mustard, J. F.

    2013-12-01

    Over the last decade, the Brazilian state of Mato Grosso has both expanded and intensified its agricultural production to become the country's leading producer of soy, corn, and cotton. Yet this increase in agricultural production may be threatened due to changes in the region's climate stemming from deforestation caused by the agricultural expansion itself. The sensitivity of Mato Grosso's agriculture to climate variability has important implications for both climate change mitigation and climate adaptation. The vast bulk of research on the drivers of land use change in the region has examined economic and institutional drivers. Leveraging a novel remote sensing-derived dataset classifying shifts between single (cultivating one commercial crop per growing season) and double cropping (cultivating two commercial crops per growing season), we investigated the influence of climate variability on land use change during the period 2000 to 2011. Over the past decade, over half of Mato Grosso's farm area transitioned from single cropping to double cropping. We used regression analysis (controlling for space and time fixed effects) to show monthly rainfall, monthly temperature, agricultural commodity prices, and agricultural revenue to be the main drivers of adoption of double cropping and reversion to single cropping in the region. The influence of climate varies as much as five orders of magnitude across these outcomes, with both temperature and precipitation exhibiting the largest climatic influence on the transition from single to double cropping. Temperature consistently proves to be more important, explaining three times more of the variance than precipitation for each outcome. Months at the beginning of a given first crop season, the end of that first crop season, and middle of the subsequent second crop season are particularly important for planting decisions in the subsequent growing year. Fitting our land transition models using remote-sensing derived

  6. Developing seasonal rainfall scenarios for food security early warning

    NASA Astrophysics Data System (ADS)

    Husak, Gregory J.; Funk, Christopher C.; Michaelsen, Joel; Magadzire, Tamuka; Goldsberry, Kirk P.

    2013-10-01

    Rainfed agriculture in Sub-Saharan Africa accounts for 95 % of the local cereal production, impacting hundreds of millions of people. Early identification of poor rainfall conditions is a critical indicator of food security. As such, monitoring accumulated seasonal rainfall gives an important mid-season estimate of final accumulated totals. However, characterizing the remaining uncertainty in a season has largely been ignored by the food security community. This paper presents a new technique describing rainfall conditions over the duration of a crop-growing cycle by combining estimated rainfall-to-date with potential scenarios for the remaining season based on available satellite rainfall estimates, the common tool for rainfall analysis in Africa. The limited historical record provided by satellite rainfall estimates using previous seasons provides only a coarse view of likely seasonal totals. To combat this, scenarios developed by bootstrapping dekadal data to create synthetic seasons allow for a finer understanding of potential seasonal accumulations. Updating this throughout the season shows a narrowing envelope of seasonal totals, converging on the final seasonal result. The resulting scenarios inform the expectations for the final seasonal rainfall accumulation, allowing analysts to quantify and visualize the uncertainty in seasonal totals. Giving decision makers a tool for understanding the likelihood of specific rainfall amounts provides additional time to enact and mobilize efforts to reduce the impact of agricultural drought.

  7. Nitrogen Cycle Modeling: a Mechanistic Estimate of N-losses From Agricultural Fields Over the Seasonal Time Period

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The biogeochemical cycle of nitrogen and production of NO, N2O, and CO2 gas and NO2- and NO3- ions in nutrient-enriched agricultural fields is mediated by soil microbial activity, the hydrological cycle, plant dynamics, and climatic forcing. Understanding how NO, N2O, CO2 gases and NO2- and NO3- io...

  8. Dealing with Climate Change and Variability in the Growing Season: a U2U Decision Support Tool for Central United States Corn Producers Based on Corn Growing Degree Days

    NASA Astrophysics Data System (ADS)

    Angel, J. R.; Todey, D.; Massey, R.; Widhalm, M.; Biehl, L. L.; Andresen, J.

    2014-12-01

    Climate extremes are a major challenge for corn producers in the central United States. Among those extremes are wet springs that lead to planting delays, late spring and early fall frosts that can damage crops, and extreme summer temperatures either too warm or too cool. A newly-operational corn growing degree-day (CGDD) tool helps producers manage and adapt to these extremes. For example, a challenge in recent years has been exceptionally wet springs that have led to significant planting delays. Producers have been forced to re-assess their planting strategies on short notice, such as switching to a faster-growing but lower-yielding hybrids. With this pattern of wetter springs projected to continue or worsen in the central United States, the problem will remain and likely get worse. Another example is helping producers identify the risk of early or late frost/freezes. The CGDD tool puts current conditions into a 30-year historical perspective and offers trend projections (based on climatology or forecasts) through the end of the calendar year. Corn, or sometimes called modified, growing degree-days use a temperature base of 10 C (50 F) and a ceiling of 30 C (86 F) and is strongly correlated with the development of the corn crop. This tool was developed as part of USDA-supported U2U Useful to Usable Project for transforming climate variability and change information for cereal crop producers.

  9. The seasonal dynamics of the stream sources and input flow paths of water and nitrogen of an Austrian headwater agricultural catchment.

    PubMed

    Exner-Kittridge, Michael; Strauss, Peter; Blöschl, Günter; Eder, Alexander; Saracevic, Ernis; Zessner, Matthias

    2016-01-15

    Our study examines the source aquifers and stream inputs of the seasonal water and nitrogen dynamics of a headwater agricultural catchment to determine the dominant driving forces for the seasonal dynamics in the surface water nitrogen loads and concentrations. We found that the alternating aquifer contributions throughout the year of the deep and shallow aquifers were the main cause for the seasonality of the nitrate concentration. The deep aquifer water typically contributed 75% of the total outlet discharge in the summer and 50% in the winter when the shallow aquifer recharges due to low crop evapotranspiration. The shallow aquifer supplied the vast majority of the nitrogen load to the stream due to the significantly higher total nitrogen concentration (11 mg-N/l) compared to the deep aquifer (0.50 mg-N/l). The main stream input pathway for the shallow aquifer nitrogen load was from the perennial tile drainages providing 60% of the total load to the stream outlet, while only providing 26% of the total flow volume. The diffuse groundwater input to the stream was the largest input to the stream (39%), but only supplied 27% to the total nitrogen load as the diffuse water was mostly composed of deep aquifer water. PMID:26562340

  10. Using a model and forecasted weather to predict forage and livestock production for making stocking decisions in the coming growing season

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forecasting peak standing crop (PSC) for the coming grazing season can help ranchers make appropriate stocking decisions to reduce enterprise risks. Previously developed PSC predictors were based on short-term experimental data (<15 yr) and limited stocking rates (SR) without including the effect of...

  11. Nitrous oxide emissions from intensive agricultural systems: Variations between crops and seasons, key driving variables, and mean emission factors

    NASA Astrophysics Data System (ADS)

    Dobbie, K. E.; McTaggart, I. P.; Smith, K. A.

    1999-11-01

    Emissions of nitrous oxide from intensively managed agricultural fields were measured over 3 years. Exponential increases in flux occurred with increasing soil water- filled pore space (WFPS) and temperature; increases in soil mineral N content due to fertilizer application also stimulated emissions. Fluxes were low when any of these variables was below a critical value. The largest fluxes occurred when WFPS values were very high (70-90%), indicating that denitrification was the major process responsible. The relationships with the driving variables showed strong similarities to those reported for very different environments: irrigated sugar cane crops, pastures, and forest in the tropics. Annual emissions varied widely (0.3-18.4 kg N2O-N ha-1). These variations were principally due to the degree of coincidence of fertilizer application and major rainfall events. It is concluded therefore that several years' data are required from any agricultural ecosystem in a variable climate to obtain a robust estimate of mean N2O fluxes. The emissions from small-grain cereals (winter wheat and spring barley) were consistently lower (0.2-0.7 kg N2O-N per 100 kg N applied) than from cut grassland (0.3-5.8 kg N2O- N per 100 kg N). Crops such as broccoli and potatoes gave emissions of the same order as those from the grassland. Although these differences between crop types are not apparent in general data comparisons, there may well be distinct regional differences in the relative and absolute emissions from different crops, due to local factors relating to soil type, weather patterns, and agricultural management practices. This will only be determined by more detailed comparative studies.

  12. Seasonal variations in surface ozone as influenced by Asian summer monsoon and biomass burning in agricultural fields of the northern Yangtze River Delta

    NASA Astrophysics Data System (ADS)

    Tang, Haoye; Liu, Gang; Zhu, Jianguo; Han, Yong; Kobayashi, Kazuhiko

    2013-03-01

    Surface ozone (O3) concentration was measured continuously at an agricultural site of Jiangdu in the northern Yangtze River Delta (YRD), China for the period from March 2007 to December 2011. Extremely high O3 concentrations ([O3]) were frequently observed in May and June with the highest hourly mean of 144 ppb. The monthly 7-h mean of [O3] showed a bimodal pattern in the seasonal change with peaks in June and October. The depression of [O3] in summer was due mostly to the monsoonal climate, which was adverse to photochemical O3 generation. Analyses of the wind direction and air mass trajectories showed that pollutants from the industrialized area of YRD were carried by the prevailing wind, causing an increased [O3] in the spring, whereas, in the summer, frequent incursions of maritime air mass diluted the high [O3] in the polluted air mass. Furthermore, it was found that extensive open crop residue burning in central eastern China made a significant contribution to the peak [O3] in June. The increase of [O3] by the residue burning in June was estimated to be 39% on sunny days and 27% on rainy days. The inter-annual variation of [O3] showed that [O3] in June tends to be lower in the years with more maritime air mass incursions, and the lowest [O3] in June 2008 could be partially attributed to the low frequency of residue burning events. This study has thus demonstrated that the variations in marine air mass incursions as influenced by the monsoonal climate and the open crop residue burning are the major determinants of the seasonal trends in surface [O3] across the agricultural areas of the northern YRD.

  13. Multi-Season Regional Analysis of Multi-Species Occupancy: Implications for Bird Conservation in Agricultural Lands in East-Central Argentina

    PubMed Central

    Goijman, Andrea Paula; Conroy, Michael. J.; Bernardos, Jaime Nicolás; Zaccagnini, María Elena

    2015-01-01

    Rapid expansion and intensification of agriculture create challenges for the conservation of biodiversity and associated ecosystem services. In Argentina, the total row crop planted area has increased in recent decades with the expansion of soybean cultivation, homogenizing the landscape. In 2003 we started the first long-term, large-scale bird monitoring program in agroecosystems of central Argentina, in portions of the Pampas and Espinal ecoregions. Using data from this program, we evaluated the effect of land use and cover extent on birds between 2003-2012, accounting for imperfect detection probabilities using a Bayesian hierarchical, multi-species and multi-season occupancy model. We tested predictions that species diversity is positively related to habitat heterogeneity, which in intensified agroecosystems is thought to be mediated by food availability; thus the extent of land use and cover is predicted to affect foraging guilds differently. We also infer about ecosystem services provisioning and inform management recommendations for conservation of birds. Overall our results support the predictions. Although many species within each guild responded differently to land use and native forest cover, we identified generalities for most trophic guilds. For example, granivorous gleaners, ground insectivores and omnivores responded negatively to high proportions of soybean, while insectivore gleaners and aerial foragers seemed more tolerant. Habitat heterogeneity would likely benefit most species in an intensified agroecosystem, and can be achieved with a diversity of crops, pastures, and natural areas within the landscape. Although most studied species are insectivores, potentially beneficial for pest control, some guilds such as ground insectivores are poorly represented, suggesting that agricultural intensification reduces ecological functions, which may be recovered through management. Continuation of the bird monitoring program will allow us to continue to

  14. Multi-Season Regional Analysis of Multi-Species Occupancy: Implications for Bird Conservation in Agricultural Lands in East-Central Argentina.

    PubMed

    Goijman, Andrea Paula; Conroy, Michael J; Bernardos, Jaime Nicolás; Zaccagnini, María Elena

    2015-01-01

    Rapid expansion and intensification of agriculture create challenges for the conservation of biodiversity and associated ecosystem services. In Argentina, the total row crop planted area has increased in recent decades with the expansion of soybean cultivation, homogenizing the landscape. In 2003 we started the first long-term, large-scale bird monitoring program in agroecosystems of central Argentina, in portions of the Pampas and Espinal ecoregions. Using data from this program, we evaluated the effect of land use and cover extent on birds between 2003-2012, accounting for imperfect detection probabilities using a Bayesian hierarchical, multi-species and multi-season occupancy model. We tested predictions that species diversity is positively related to habitat heterogeneity, which in intensified agroecosystems is thought to be mediated by food availability; thus the extent of land use and cover is predicted to affect foraging guilds differently. We also infer about ecosystem services provisioning and inform management recommendations for conservation of birds. Overall our results support the predictions. Although many species within each guild responded differently to land use and native forest cover, we identified generalities for most trophic guilds. For example, granivorous gleaners, ground insectivores and omnivores responded negatively to high proportions of soybean, while insectivore gleaners and aerial foragers seemed more tolerant. Habitat heterogeneity would likely benefit most species in an intensified agroecosystem, and can be achieved with a diversity of crops, pastures, and natural areas within the landscape. Although most studied species are insectivores, potentially beneficial for pest control, some guilds such as ground insectivores are poorly represented, suggesting that agricultural intensification reduces ecological functions, which may be recovered through management. Continuation of the bird monitoring program will allow us to continue to

  15. Xylogenesis: Coniferous Trees of Temperate Forests Are Listening to the Climate Tale during the Growing Season But Only Remember the Last Words!

    PubMed

    Cuny, Henri E; Rathgeber, Cyrille B K

    2016-05-01

    The complex inner mechanisms that create typical conifer tree-ring structure (i.e. the transition from large, thin-walled earlywood cells to narrow, thick-walled latewood cells) were recently unraveled. However, what physiological or environmental factors drive xylogenesis key processes remain unclear. Here, we aim to quantify the influence of seasonal variations in climatic factors on the spectacular changes in the kinetics of wood cell differentiation and in the resulting tree-ring structure. Wood formation was monitored in three sites over 3 years for three coniferous species (Norway spruce [Picea abies], Scots pine [Pinus sylvestris], and silver fir [Abies alba]). Cell differentiation rates and durations were calculated and related to tracheid final dimensions and corresponding climatic conditions. On the one hand, we found that the kinetics of cell enlargement and the final size of the tracheids were not explained by the seasonal changes in climatic factors. On the other hand, decreasing temperatures strongly constrained cell wall deposition rates during latewood formation. However, the influence of temperature was permanently written into tree-ring structure only for the very last latewood cells, when the collapse of the rate of wall deposition was no longer counterbalanced by the increase of its duration. Our results show that the formation of the typical conifer tree-ring structure, in normal climatic conditions, is only marginally driven by climate, suggesting strong developmental control of xylogenesis. The late breakage of the compensatory mechanism at work in the wall deposition process appears as a clue to understand the capacity of the maximum latewood density to record past temperature conditions. PMID:27208048

  16. Historical warnings of future food insecurity with unprecedented seasonal heat.

    PubMed

    Battisti, David S; Naylor, Rosamond L

    2009-01-01

    Higher growing season temperatures can have dramatic impacts on agricultural productivity, farm incomes, and food security. We used observational data and output from 23 global climate models to show a high probability (>90%) that growing season temperatures in the tropics and subtropics by the end of the 21st century will exceed the most extreme seasonal temperatures recorded from 1900 to 2006. In temperate regions, the hottest seasons on record will represent the future norm in many locations. We used historical examples to illustrate the magnitude of damage to food systems caused by extreme seasonal heat and show that these short-run events could become long-term trends without sufficient investments in adaptation. PMID:19131626

  17. Trace gases and particulate matter emissions from wildfires and agricultural burning in Northeastern Mexico during the 2000 fire season.

    PubMed

    Mendoza, Alberto; Garcia, Marisa R; Vela, Patricia; Lozano, D Fabian; Allen, David

    2005-12-01

    An inventory of air pollutants emitted from forest and agricultural fires in Northeastern Mexico for the period of January to August of 2000 is presented. The emissions estimates were calculated using an emissions factor methodology. The inventory accounts for the emission of carbon monoxide (CO), methane, nonmethane hydrocarbons, ammonia, nitrogen oxides, and particulate matter (PM). Particulate matter emissions include estimates for fine PM and coarse PM. A total of 2479 wildfires were identified in the domain for the period of interest, which represented approximately 810,000 acres burned and 621,130 short tons emitted (81% being CO). The main source of information used to locate and estimate the extent of the fires came from satellite imagery. A geographic information system was used to determine the type of vegetation burned by each fire. More than 54% of the total area burned during the period of study was land on the State of Tamaulipas. However, >58% of the estimated emissions came from the State of Coahuila. This was because of the mix of vegetation types burned in each state. With respect to the temporal distribution, 76.9% of the fires occurred during the months of April and May consuming almost 78% of the total area burned during the period of study. Analysis of wind forward trajectories of air masses passing through the burned areas and 850-mb wind reanalyses indicate possible transboundary transport of the emissions from Mexico to the United States during the occurrence of the major wildfires identified. PMID:16408684

  18. Intake, digestibility, nitrogen efficiency, and animal performance of growing and finishing beef cattle fed warm-season legume (Stylosanthes capitata plus Stylosanthes macrocephala) silage replacing corn silage.

    PubMed

    Souza, W F; Pereira, O G; Ribeiro, K G; Santos, S A; Valadares Filho, S C

    2014-09-01

    It was hypothesized that Stylosanthes cv. Campo Grande (ES) silage could be used as the single source of dietary forage for beef cattle and that performance on ES would be similar to corn silage (CS) at a 50:50 forage:concentrate. The objectives of this study were to evaluate intake, total and partial digestibility of nutrients, ruminal pH, ruminal ammonia, and productive performance in growing beef cattle fed diets with varying proportions of ES silage replacing CS. Treatments consisted of diets with ratios of 0:100, 25:75, 50:50, 75:25, and 100:0% ES:CS. Two experiments were conducted simultaneously. In the first experiment, 10 crossbred Holstein-Zebu bulls with an average initial weight of 272 ± 86 kg were used. The bulls were rumen and abomasums fistulated. An experimental design of two 5 × 5 Latin squares (Exp. 1) was used. The second experiment used 40 Nellore bulls with an average BW of 386 ± 30 kg in a completely randomized design (Exp. 2). Results showed a linear increase in CP intake (P < 0.05) in response to increased dietary ES. An increase in the proportion of ES in the diet had a negative linear effect on TDN. Apparent ruminal digestibility of CP increased linearly, and apparent intestinal digestibility of nonfibrous carbohydrates increased with the addition of ES to the diet (P < 0.05). Intestinal digestibility of DM exhibited a quadratic response (P < 0.05). Nitrogen balance, excretion of urinary urea, and plasma urea nitrogen did not respond to the inclusion of ES in the diet (P > 0.05). There was also no effect (P > 0.05) of ES inclusion on animal performance. Ruminal pH was not affected by an increased proportion of ES in the diet (P > 0.05), but ruminal pH was affected (P < 0.05) by the time of collection, for which a cubic model fit the data. There was an interaction (P < 0.05) between treatment and collection time for ruminal ammonia nitrogen concentration. It can be concluded that ES silage can be used as a source of roughage in the diet

  19. A Case Study of the Basic Education Project for the Children of Seasonal Agricultural Workers in the Cukurova Region in Turkey. Mid-Decade Review of Progress towards Education for All.

    ERIC Educational Resources Information Center

    Guner, Barbaros; Simsek, Hasan; Yildirim, Ali

    In 1995, the International Consultative Forum on Education for All commissioned case studies in developing countries as part of a mid-decade review of progress in expanding access to basic education. This paper examines a project in Turkey that provided basic education and health services to the children of seasonal agricultural workers. Between…

  20. 7 CFR 916.15 - Marketing season.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Marketing season. 916.15 Section 916.15 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Definitions § 916.15 Marketing season. Marketing season means the period beginning...

  1. 7 CFR 916.15 - Marketing season.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Marketing season. 916.15 Section 916.15 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Definitions § 916.15 Marketing season. Marketing season means the period beginning...

  2. Monitoring of a fast-growing speleothem site from the Han-sur-Lesse cave, Belgium, indicates equilibrium deposition of the seasonal δ18O and δ13C signals in the calcite

    NASA Astrophysics Data System (ADS)

    Van Rampelbergh, M.; Verheyden, S.; Allan, M.; Quinif, Y.; Keppens, E.; Claeys, P.

    2014-10-01

    Speleothems provide paleoclimate information on multimillennial to decadal scales in the Holocene. However, seasonal or even monthly resolved records remain scarce. Such records require fast-growing stalagmites and a good understanding of the proxy system on very short timescales. The Proserpine stalagmite from the Han-sur-Less cave (Belgium) displays well-defined/clearly visible darker and lighter seasonal layers of 0.5 to 2 mm thickness per single layer, which allows a measuring resolution at a monthly scale. Through a regular cave monitoring, we acquired a good understanding of how δ18O and δ13C signals in modern calcite reflect climate variations on the seasonal scale. From December to June, outside temperatures are cold, inducing low cave air and water temperature, and bio-productivity in the soil is limited, leading to lower pCO2 and higher δ13C values of the CO2 in the cave air. From June to December, the measured factors display an opposite behavior. The absence of epikarst water recharge between May and October increases prior calcite precipitation (PCP) in the vadose zone, causing drip water to display increasing pH and δ13C values over the summer months. Water recharge of the epikarst in winter diminishes the effect of PCP and as a result the pH and δ13C of the drip water gradually decrease. The δ18O and δ13C signals of fresh calcite precipitated on glass slabs also vary seasonally and are both reflecting equilibrium conditions. Lowest δ18O values occur during the summer, when the δ13C values are high. The δ18O values of the calcite display seasonal variations due to changes in the cave air and water temperature. The δ13C values reflect the seasonal variation of the δ13CDIC of the drip water, which is affected by the intensity of PCP. This same anticorrelation of the δ18O versus the δ13C signals is seen in the monthly resolved speleothem record that covers the period between 1976 and 1985 AD. Dark layers display lower δ18O and higher δ13C

  3. Use of Weighted Regressions on Time, Discharge, and Season to Assess Effectiveness of Agricultural and Environmental Best Management Practices in California and Nevada, USA

    NASA Astrophysics Data System (ADS)

    Domagalski, J. L.; Schlegel, B.; Hutchins, J.

    2014-12-01

    Long-term data sets on stream-water quality and discharge can be used to assess whether best management practices (BMPs) are restoring beneficial uses of impaired water as required under the Clean Water Act. In this study, we evaluated a greater than 20-year record of water quality from selected streams in the Central Valley (CV) of California and Lake Tahoe (California and Nevada, USA). The CV contains a mix of agricultural and urbanized land, while the Lake Tahoe area is mostly forested, with seasonal residents and tourism. Because nutrients and fine sediments cause a reduction in water clarity that impair Lake Tahoe, BMPs were implemented in the early 1990's, to reduce nitrogen and phosphorus loads. The CV does not have a current nutrient management plan, but numerous BMPs exist to reduce pesticide loads, and it was hypothesized that these programs could also reduce nutrient levels. In the CV and Lake Tahoe areas, nutrient concentrations, loads, and trends were estimated by using the recently developed Weighted Regressions on Time, Discharge, and Season (WRTDS) model. Sufficient data were available to compare trends during a voluntary and enforcement period for seven CV sites within the lower Sacramento and San Joaquin Basins. For six of the seven sites, flow-normalized mean annual concentrations of total phosphorus and nitrate decreased at a faster rate during the enforcement period than during the earlier voluntary period. Concentration changes during similar years and ranges of flow conditions suggest that BMPs designed for pesticides also reduced nutrient loads in the CV. A trend analysis using WRTDS was completed for six streams that enter Lake Tahoe during the late 1980's through 2008. The results of the model confirm that nutrient loading is influenced strongly by season, such as by spring runoff from snowmelt. The highest nutrient concentrations in the late 1980's and early 1990's correlate with high flows, followed by statistically significant decreases

  4. Heavy metal content in ash of energy crops growing in sewage-contaminated natural wetlands: potential applications in agriculture and forestry?

    PubMed

    Bonanno, Giuseppe; Cirelli, Giuseppe Luigi; Toscano, Attilio; Lo Giudice, Rosa; Pavone, Pietro

    2013-05-01

    One of the greatest current challenges is to find cost-effective and eco-friendly solutions to the ever increasing needs of modern society. Some plant species are suitable for a multitude of biotechnological applications such as bioenergy production and phytoremediation. A sustainable practice is to use energy crops to clean up polluted lands or to treat wastewater in constructed wetlands without claiming further arable land for biofuel production. However, the disposal of combustion by-products may add significant costs to the whole process, especially when it deals with toxic waste. This study aimed to investigate the possibility of recycling ash from energy biomass as a fertilizer for agriculture and forestry. In particular, the concentrations of Cd, Cr, Cu, Mn, Pb and Zn were analyzed in the plant tissues and corresponding ash of the grasses Phragmites australis and Arundo donax, collected in an urban stream affected by domestic sewage. Results showed that the metal concentration in ash is 1.5-3 times as high as the values in plant tissues. However, metal enriched ash showed much lower element concentrations than the legal limits for ash reutilization in agriculture and forestry. This study found that biomass ash from constructed wetlands may be considered as a potential fertilizer rather than hazardous waste. Energy from biomass can be a really sustainable and clean option not only through the reduction of greenhouse gas emissions, but also through ash recycling for beneficial purposes, thus minimizing the negative impacts of disposal. PMID:23534998

  5. Responses to Global Warming Over the Eastern and Central Tibetan Plateau as Reflected in Day-time and Night-time Temperatures, Extreme Temperature Events, and Growing Season Length During 1961-2003

    NASA Astrophysics Data System (ADS)

    Yin, Z.; Liu, X.; Shao, X.

    2006-12-01

    This study examines the trends and variation patterns in daily maximum (day-time) and minimum (night-time) temperatures (hereafter referred to as Tm and Tn), extreme events, and growing season lengths over the eastern and central Tibetan Plateau (TP), in comparison with the results from other regions. Data during the period 1961-2003 from 66 weather stations over the eastern and central TP with elevations above 2000 m are used in this study, after going through rigorous quality assessment/quality control procedures. Statistically significant warming trends are identified in various measures of the temperature regime, especially in night- time temperatures, extreme warm/cold events, and diurnal temperature range (DTR). We find that the trends in Tn and Tm display distinct spatial patterns in the study region. The warming trends in winter night-time temperatures are among the highest when compared with studies conducted in other regions. Our results also confirm the asymmetric pattern of greater warming trends in minimum or night-time temperatures as compared to the day-time temperatures, which reduces the DTR in the region. Based on the time-varying percentiles of Tn and Tm, prominent warming trends are found in Tn during cold season months across the relative temperature scale of both warm and cold events. The warming in night-time temperatures causes the number of frost days to decrease significantly and the number of warm days to increase. The mean length of growing season has increased by approximately 17 days during the 43-year study period for the region. Most of the record-setting months for cold events are found in the earlier part of the study period, while that of the warm events have occurred mostly in the later half, especially since the 1990s. The changes in the temperature regime in this region may have brought regional-specific impacts on the ecosystems. It is found that grain production in Qinghai Province, located in the northeastern part of the

  6. Tetracycline Resistance and Presence of Tetracycline Resistance Determinants tet(V) and tap in Rapidly Growing Mycobacteria from Agricultural Soils and Clinical Isolates

    PubMed Central

    Kyselková, Martina; Chron̂áková, Alica; Volná, Lucie; Nêmec, Jan; Ulmann, Vít; Scharfen, Josef; Elhottová, Dana

    2012-01-01

    Rapidly growing mycobacteria (RGM) inhabit soil and water but certain strains represent a health risk for human and animals. Both clinical and soil RGM may be under selection pressure for resistance to tetracycline (TET) antibiotics, since tetracyclines are administrated to humans and farm animals, and TET residues enter soil through manuring; however, resistance to TET and the presence of TET-resistance genes have been assessed only in clinical isolates. We were therefore interested in comparing soil and clinical RGM in terms of TET resistance and the presence of TET-resistance genes. We used 44 RGM from grasslands with different exposure to animal manure, and 38 clinical RGM from Czech hospitals. There was no difference between the clinical and soil isolates in TET resistance, with >50% resistant isolates in both groups. otr(A), otr(B), tet(K), tet(L) or tet(M) were not detected in any soil or clinical isolate. In contrast, most isolates harbored tet(V) and tap, both encoding mycobacterial efflux pumps, including species where these genes have never been evidenced before. The phylogeny of tet(V) correlated with isolates’ BOX-PCR profiles, suggesting that this gene evolved along with mycobacterial genomes as a part of the intrinsic resistome. In certain cases, tet(V) and/or tap were found in TET-sensitive isolates, or inversely, were not found in resistant strains. Concluding, intrinsic efflux pumps may be more important for TET resistance than horizontally transferred genes in both soil and clinical RGM. Their simple presence, however, does not attest to resistance, and therefore their diversity, function and expression merit further research. PMID:22673307

  7. A framework for developing an impact-oriented agricultural drought monitoring system from remote sensing

    NASA Astrophysics Data System (ADS)

    Zhang, Jie

    2016-04-01

    With a changing climate, drought has become more intensified, of which agriculture is the major affected sector. Satellite observations have proven great utilities for real-time drought monitoring as well as crop yield estimation, and many remotely sensed indicators have been developed for drought monitoring based on vegetation growth conditions, surface temperature and evapotranspiration information. However, those current drought indicators typically don't take into account the different responses of various input information and the drought impacts during the growing season, revealing some limitations for effective agricultural drought monitoring and impact analysis. Therefore, the goal of this research is to build a framework for the development of an impact-oriented and remote sensing based agricultural drought indicator. Firstly, the global agricultural drought risk was characterized to provide an overview of the agricultural drought prone areas in the world. Then, the responses of different remotely sensed indicators to drought and the impacts of drought on crop yield from the remote sensing perspective during the growing season were explored. Based on previous works on drought risk, drought indicator response and drought impact analysis, an impact-oriented drought indicator will be prototyped from the integration of the drought responses of different indicators and the drought impacts during the growing season. This research can inform an impact-oriented agricultural drought indicator, help prototype an impact-oriented agricultural drought monitoring system, and thus provide valuable inputs for effective agricultural management.

  8. America's water: Agricultural water demands and the response of groundwater

    NASA Astrophysics Data System (ADS)

    Ho, M.; Parthasarathy, V.; Etienne, E.; Russo, T. A.; Devineni, N.; Lall, U.

    2016-07-01

    Agricultural, industrial, and urban water use in the conterminous United States (CONUS) is highly dependent on groundwater that is largely drawn from nonsurficial wells (>30 m). We use a Demand-Sensitive Drought Index to examine the impacts of agricultural water needs, driven by low precipitation, high agricultural water demand, or a combination of both, on the temporal variability of depth to groundwater across the CONUS. We characterize the relationship between changes in groundwater levels, agricultural water deficits relative to precipitation during the growing season, and winter precipitation. We find that declines in groundwater levels in the High Plains aquifer and around the Mississippi River Valley are driven by groundwater withdrawals used to supplement agricultural water demands. Reductions in agricultural water demands for crops do not, however, lead to immediate recovery of groundwater levels due to the demand for groundwater in other sectors in regions such as Utah, Maryland, and Texas.

  9. Comparison of Irrigation Water Use Estimates Calculated from Remotely Sensed Irrigated Acres and State Reported Irrigated Acres in the Lake Altus Drainage Basin, Oklahoma and Texas, 2000 Growing Season

    USGS Publications Warehouse

    Masoner, J.R.; Mladinich, C.S.; Konduris, A.M.; Smith, S. Jerrod

    2003-01-01

    Increased demand for water in the Lake Altus drainage basin requires more accurate estimates of water use for irrigation. The U.S. Geological Survey, in cooperation with the U.S. Bureau of Reclamation, is investigating new techniques to improve water-use estimates for irrigation purposes in the Lake Altus drainage basin. Empirical estimates of reference evapotranspiration, crop evapotranspiration, and crop irrigation water requirements for nine major crops were calculated from September 1999 to October 2000 using a solar radiation-based evapotranspiration model. Estimates of irrigation water use were calculated using remotely sensed irrigated crop acres derived from Landsat 7 Enhanced Thematic Mapper Plus imagery and were compared with irrigation water-use estimates calculated from irrigated crop acres reported by the Oklahoma Water Resources Board and the Texas Water Development Board for the 2000 growing season. The techniques presented will help manage water resources in the Lake Altus drainage basin and may be transferable to other areas with similar water management needs. Irrigation water use calculated from the remotely sensed irrigated acres was estimated at 154,920 acre-feet; whereas, irrigation water use calculated from state reported irrigated crop acres was 196,026 acre-feet, a 23 percent difference. The greatest difference in irrigation water use was in Carson County, Texas. Irrigation water use for Carson County, Texas, calculated from the remotely sensed irrigated acres was 58,555 acrefeet; whereas, irrigation water use calculated from state reported irrigated acres was 138,180 acre-feet, an 81 percent difference. The second greatest difference in irrigation water use occurred in Beckham County, Oklahoma. Differences between the two irrigation water use estimates are due to the differences of irrigated crop acres derived from the mapping process and those reported by the Oklahoma Water Resources Board and Texas Water Development Board.

  10. Lengthening Spring Season in Southwestern North America

    NASA Astrophysics Data System (ADS)

    Gutzler, D. S.

    2014-12-01

    Climate is changing rapidly in southwestern North America during the Spring season, a critically important transition season in terms of hydrology, ecosystem dynamics, and water resource management. Major rivers are snow-fed in mountainous headwaters but then flow through a monsoonal region with a Summer precipitation maximum; Spring is the dry season in between snowmelt and monsoon onset and is the principal wildfire season in the Southwest. Evaporation during the warm, dry Spring represents a major hydrologic loss in the surface water budget and is a principal cause of projections of significant decreases in post-snowmelt streamflow, during the first half of the growing season when demand for surface water for irrigated agriculture is highest. As temperatures increase, snowpack is expected to decrease and melt earlier, leading to a smaller and earlier peak in snowmelt runoff. Recent climate model projections suggest that monsoon onset should occur later in the year, delaying the summer rainy season. Each of these effects contributes to projections of a lengthening Spring season, at both the beginning and end of Spring. A longer, warmer Spring season is associated with significant surface drying and increased wildfire risk in the 21st Century across the Southwest. So far changes are observed at the beginning of spring in terms of temperature (increasing) and snowpack (decreasing). Detection of other changes, including metrics of the end of spring, has not been easy, in part due to the huge natural variability of precipitation that affects hydrologic variables in conjunction with temperature. This presentation describes efforts to diagnose and document observed changes in the transitions into and out of the Spring dry season in the Southwest, in variables such as temperature, snowmelt date, timing and magnitude of streamflow, and monsoon onset date.

  11. A Two-Tier Statistical Forecast Method for Agricultural and Resource Management Simulations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simple conditional methods to predict growing season climate based on the state of leading ENSO sea-surface temperature (SSTA) and sea-level pressure anomaly (SLPA) indicators provide the means to model and study the effects of forecast information in agriculture, but may be limited in their accurac...

  12. MAPPING AND SCOUTING CORN PEST INFESTATIONS IN A PRODUCTION AGRICULTURE ENVIRONMENT USING REMOTE SENSING.

    EPA Science Inventory

    Hyperspectral imagery was acquired three times during the 2006 agricultural growing season (late July to mid-September) over 35 corn fields in east central Illinois. The imagery was processed with an emphasis on rapid image product development (turnabround time of less than 24 ho...

  13. 7 CFR 319.37-8 - Growing media.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Growing media. 319.37-8 Section 319.37-8 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Plants for Planting 1, 2 § 319.37-8 Growing media. (a) Any restricted article at the time...

  14. Sensory Profiles and Seasonal Variation of Black Walnut Cultivars.

    PubMed

    Lynch, Catherine; Koppel, Kadri; Reid, William

    2016-03-01

    Black walnut (Juglans nigra L.) is a North American hardwood tree valued for producing nuts and wood. Black walnut cultivars were evaluated by a trained panel over 2 growing seasons to determine the seasonal variation in the sensory profile. Results showed that cultivars were significantly different on 3 appearance (skin color, nutmeat color, and kernel roughness), 1 aroma (black walnut ID), 5 flavor (black walnut ID, banana-like, piny, rancid, and overall nutty), and 2 texture attributes (surface roughness and hardness). These profiles were compared to results collected in 2011 to determine differences between growing seasons. Results showed 4 flavor attributes (black walnut ID, overall nutty, fruity-dark and rancid) had an interaction effect of year and cultivar, while 6 attributes (brown, caramelized, floral/fruity, piny, musty/dusty, and oily) showed a main effect of year. In general, flavor attributes had higher intensities in 2011 than in 2013. These results suggest that seasonal variation may influence flavor profile more than cultivar. Thus, using samples from only 1 growing season when testing agricultural products may not provide adequate information for the long term. PMID:26849318

  15. Agricultural crops and soil treatment impacts on the daily and seasonal dynamics of CO2 fluxes in the field agroecosystems at the Central region of Russia

    NASA Astrophysics Data System (ADS)

    Mazirov, Ilya; Vasenev, Ivan; Meshalkina, Joulia; Yaroslavtsev, Alexis; Berezovskiy, Egor; Djancharov, Turmusbek

    2015-04-01

    The problem of greenhouse gases' concentrations increasing becomes more and more important due to global changes issues. The main component of greenhouse gases is carbon dioxide. The researches focused on its fluxes in natural and anthropogenic modified landscapes can help in this problem solution. Our research has been done with support of the RF Government grants # 11.G34.31.0079 and # 14.120.14.4266 and of FP7 Grant # 603542 LUC4C in the representative for Central Region of Russia field agroecosystems at the Precision Farming Experimental Field of Russian Timiryazev State Agrarian University with cultivated sod podzoluvisols, barley and oats - vetch grass mix (Moscow station of the RusFluxNet). The daily and seasonal dynamics of the carbon dioxide have been studied at the ecosystem level by the Eddy covariance method (2 stations) and at the soil level by the exposition chamber method (40 chambers) with mobile infra red gas analyzer (Li-Cor 820). The primary Eddy covariance monitoring data on CO2 fluxes and water vapor have been processed by EddyPro software developed by LI-COR Biosciences. According to the two-year monitoring data the daily CO2 sink during the vegetation season is usually approximately two times higher than its emission at night. Seasonal CO2 fluxes comparative stabilization has been fixed in case the plants height around 10-12 cm and it usually persist until the wax ripeness phase. There is strong dependence between the soil CO2 emission and the air temperature with the correlation coefficient 0.86 in average (due to strong input of the soil thin top functional subhorizon), but it drops essentially at the end of the season - till 0.38. The soil moisture impact on CO2 fluxes dynamics was less, with negative correlation at the end of the season. High daily dynamics of CO2 fluxes determines the protocol requirements for seasonal soil monitoring investigation with less limitation at the end of the season. The accumulated monitoring data will be

  16. Expressing the sense of the House of Representatives that specialty crops are a vital part of agriculture in the United States, that the Committee on Agriculture should propose funding for programs that support specialty crops priorities, and that legislation should be passed that includes funding reflecting specialty crops as a growing and important part of United States agriculture.

    THOMAS, 113th Congress

    Rep. DelBene, Suzan K. [D-WA-1

    2013-04-25

    05/03/2013 Referred to the Subcommittee on Horticulture, Research, Biotechnology, and Foreign Agriculture. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  17. The Use of Uas for Assessing Agricultural Systems in AN Wetland in Tanzania in the - and Wet-Season for Sustainable Agriculture and Providing Ground Truth for Terra-Sar X Data

    NASA Astrophysics Data System (ADS)

    Thamm, H.-P.; Menz, G.; Becker, M.; Kuria, D. N.; Misana, S.; Kohn, D.

    2013-08-01

    The paper describes the assessment of the vegetation and the land use systems of the Malinda Wetland in the Usambara Mountains in Tanzania with the parachute UAS (unmanned aerial system) SUSI 62. The area of investigation was around 8 km2. In two campaigns, one in the wet season and one in the dry season, approximately 2600 aerial photos of the wetland were taken using the parachute UAS SUSI 62; of these images, ortho-photos with a spatial resolution of 20 cm x 20 cm, were computed with an advanced block bundle approach. The block bundles were geo-referenced using control points taken with differential GPS. As well a digital surface model (DSM) of the wetland was created out of the UAS photos. Using the ortho-photos it is possible to assess the different land use systems; the differences in the phenology of the vegetation between wet and dry season can be investigated. In addition, the regionalisation of bio mass samples on smaller test plots was possible. The ortho-photos and the DSM derived from the UAS proved to be a valuable ground truth for the interpretation of Terra-SAR X images. The campaigns demonstrated that SUSI 62 was a suitable, robust tool to obtain the valuable information under harsh conditions.

  18. Seasonal drought forecast system for food-insecure regions of East Africa

    NASA Astrophysics Data System (ADS)

    Shukla, Shraddhanand; McNally, Amy; Husak, Greg; Funk, Chris

    2014-05-01

    In East Africa, agriculture is mostly rainfed and hence sensitive to interannual rainfall variability, and the increasing food and water demands of a growing population place further stresses on the water resources of this region. Skillful seasonal agricultural drought forecasts for this region can inform timely water and agricultural management decisions, support the proper allocation of the region's water resources, and help mitigate socio-economic losses. Here we describe the development and implementation of a seasonal drought forecast system that is being used for providing seasonal outlooks of agricultural drought in East Africa. We present a test case of the evaluation and applicability of this system for March-April-May growing season over equatorial East Africa (latitude 20 south to 80 North and 360 E to 460E) that encompasses one of the most food insecure and climatically and socio-economically vulnerable regions in East Africa. This region experienced famine as recently as in 2011. The system described here combines advanced satellite and re-analysis as well as station-based long term and real-time observations (e.g. NASA's TRMM, Infra-red remote sensing, Climate Forecast System Reanalysis), state-of-the-art dynamical climate forecast system (NCEP's Climate Forecast System Verison-2) and large scale land surface models (e.g. Variable Infiltration Capacity, NASA's Land Information System) to provide forecasts of seasonal rainfall, soil moisture and Water Requirement Satisfaction Index (WRSI) throughout the season - with an emphasis on times when water is the most critical: start of season/planting and the mid-season/crop reproductive phase. Based on the hindcast assessment of this system, we demonstrate the value of this approach to the US Agency for International Development (USAID)'s efforts to mitigate future losses of lives and economic losses by allowing a proactive approach of drought management that includes early warning and timely action.

  19. Measuring efficiency of rice growing farmers using data envelopment analysis

    NASA Astrophysics Data System (ADS)

    Zaibidi, Nerda Zura; Kasim, Maznah Mat; Ramli, Razamin; Baten, Md. Azizul; Khan, Sahubar Ali Nadhar

    2015-12-01

    Self-sufficiency in rice production has been the main issue in Malaysia agriculture. It is significantly low and does not comply with the current average rice yield of 3.7 tons per ha per season. One of the best options and the most effective way to improve rice productivity is through more efficient utilization of paddy farmers. Getting farmers to grow rice is indeed a challenge when they could very well be making better money doing something else. This paper attempts to study the efficiency of rice growing farmers in Kubang Pasu using Data Envelopment Analysis model. For comparative analysis, three scenarios are considered in this study in measuring efficiency of rice growing farmers. The first scenario considers only fertilizer factor as an input while for the second, the land size is added as another factor. The third scenario considers more details about the inputs such as the type of fertilizer, NPK and mixed and also land tenureship and size. In all scenarios, the outputs are rice yield (tons) and the profit (RM). As expected, the findings show that the third scenario establishes the highest number of efficient rice growing farmers. It reveals that the combination of outputs and inputs chosen has significant contribution in measuring efficiency of rice growing farmers.

  20. Hydrology of a zero-order Southern Piedmont watershed through 45 years of changing agricultural land use. Part 1. Monthly and seasonal rainfall-runoff relationships

    NASA Astrophysics Data System (ADS)

    Endale, Dinku M.; Fisher, Dwight S.; Steiner, Jean L.

    2006-01-01

    Few studies have reported runoff from small agricultural watersheds over sufficiently long period so that the effect of different cover types on runoff can be examined. We analyzed 45-yrs of monthly and annual rainfall-runoff characteristics of a small (7.8 ha) zero-order typical Southern Piedmont watershed in southeastern United States. Agricultural land use varied as follows: 1. Row cropping (5-yrs); 2. Kudzu ( Pueraria lobata; 5-yrs); 3. Grazed kudzu and rescuegrass ( Bromus catharticus; 7-yrs); and 4. Grazed bermudagrass and winter annuals ( Cynodon dactylon; 28-yrs). Land use and rainfall variability influenced runoff characteristics. Row cropping produced the largest runoff amount, percentage of the rainfall partitioned into runoff, and peak flow rates. Kudzu reduced spring runoff and almost eliminated summer runoff, as did a mixture of kudzu and rescuegrass (KR) compared to row cropping. Peak flow rates were also reduced during the kudzu and KR. Peak flow rates increased under bermudagrass but were lower than during row cropping. A simple process-based 'tanh' model modified to take the previous month's rainfall into account produced monthly rainfall and runoff correlations with coefficient of determination ( R2) of 0.74. The model was tested on independent data collected during drought. Mean monthly runoff was 1.65 times the observed runoff. Sustained hydrologic monitoring is essential to understanding long-term rainfall-runoff relationships in agricultural watersheds.

  1. Dry-season length and runoff control annual variability in stream DOC dynamics in a small, shallow groundwater-dominated agricultural watershed

    NASA Astrophysics Data System (ADS)

    Humbert, G.; Jaffrezic, A.; Fovet, O.; Gruau, G.; Durand, P.

    2015-10-01

    As a phenomenon integrating climate conditions and hydrological control of the connection between streams and terrestrial dissolved organic carbon (DOC) sources, groundwater dynamics control patterns of stream DOC characteristics (concentrations and fluxes). Influence of intra-annual variations in groundwater level, discharge and climatic factors on DOC concentrations and fluxes were assessed over 13 years at the headwater watershed of Kervidy-Naizin (5 km2) in western France. Four seasonal periods were delineated within each year according to groundwater fluctuations (A: rewetting, B: high flow, C: recession, and D: drought). Annual and seasonal base flow versus stormflow DOC concentrations were defined based on daily hydrograph readings. High interannual variability of annual DOC fluxes (5.4-39.5 kg ha-1 yr-1) indicates that several years of data are required to encompass variations in water flux to evaluate the actual DOC export capacity of a watershed. Interannual variability of mean annual DOC concentrations was much lower (4.9-7.5 mg C L-1), with concentrations decreasing within each year from ca. 9.2 mg C L-1 in A to ca. 3.0 mg C L-1 in C. This indicates an intra-annual pattern of stream DOC concentrations controlled by DOC source characteristics and groundwater dynamics very similar across years. Partial least squares regressions combined with multiple linear regressions showed that the dry season characteristics (length and drawdown) determine the mean annual DOC concentration while annual runoff determines the annual flux. Antagonistic mechanisms of production-accumulation and dilution-depletion combined with an unlimited DOC supply from riparian wetland soils can mitigate the response of stream concentrations to global changes and climatic variations.

  2. Development of a regionally consistent geospatial dataset of agricultural lands in the Upper Colorado River Basin, 2007-10

    USGS Publications Warehouse

    Buto, Susan G.; Gold, Brittany L.; Jones, Kimberly A.

    2014-01-01

    Irrigation in arid environments can alter the natural rate at which salts are dissolved and transported to streams. Irrigated agricultural lands are the major anthropogenic source of dissolved solids in the Upper Colorado River Basin (UCRB). Understanding the location, spatial distribution, and irrigation status of agricultural lands and the method used to deliver water to agricultural lands are important to help improve the understanding of agriculturally derived dissolved-solids loading to surface water in the UCRB. Irrigation status is the presence or absence of irrigation on an agricultural field during the selected growing season or seasons. Irrigation method is the system used to irrigate a field. Irrigation method can broadly be grouped into sprinkler or flood methods, although other techniques such as drip irrigation are used in the UCRB. Flood irrigation generally causes greater dissolved-solids loading to streams than sprinkler irrigation. Agricultural lands in the UCRB mapped by state agencies at varying spatial and temporal resolutions were assembled and edited to represent conditions in the UCRB between 2007 and 2010. Edits were based on examination of 1-meter resolution aerial imagery collected between 2009 and 2011. Remote sensing classification techniques were used to classify irrigation status for the June to September growing seasons between 2007 and 2010. The final dataset contains polygons representing approximately 1,759,900 acres of agricultural lands in the UCRB. Approximately 66 percent of the mapped agricultural lands were likely irrigated during the study period.

  3. Conducting an Agricultural Life Cycle Assessment: Challenges and Perspectives

    PubMed Central

    Caffrey, Kevin R.; Veal, Matthew W.

    2013-01-01

    Agriculture is a diverse field that produces a wide array of products vital to society. As global populations continue to grow the competition for natural resources will increase pressure on agricultural production of food, fiber, energy, and various high value by-products. With elevated concerns related to environmental impacts associated with the needs of a growing population, a life cycle assessment (LCA) framework can be used to determine areas of greatest impact and compare reduction strategies for agricultural production systems. The LCA methodology was originally developed for industrial operations but has been expanded to a wider range of fields including agriculture. There are various factors that increase the complexity of determining impacts associated with agricultural production including multiple products from a single system, regional and crop specific management techniques, temporal variations (seasonally and annually), spatial variations (multilocation production of end products), and the large quantity of nonpoint emission sources. The lack of consistent methodology of some impacts that are of major concern to agriculture (e.g., land use and water usage) increases the complexity of this analysis. This paper strives to review some of these issues and give perspective to the LCA practitioner in the field of agriculture. PMID:24391463

  4. Conducting an agricultural life cycle assessment: challenges and perspectives.

    PubMed

    Caffrey, Kevin R; Veal, Matthew W

    2013-01-01

    Agriculture is a diverse field that produces a wide array of products vital to society. As global populations continue to grow the competition for natural resources will increase pressure on agricultural production of food, fiber, energy, and various high value by-products. With elevated concerns related to environmental impacts associated with the needs of a growing population, a life cycle assessment (LCA) framework can be used to determine areas of greatest impact and compare reduction strategies for agricultural production systems. The LCA methodology was originally developed for industrial operations but has been expanded to a wider range of fields including agriculture. There are various factors that increase the complexity of determining impacts associated with agricultural production including multiple products from a single system, regional and crop specific management techniques, temporal variations (seasonally and annually), spatial variations (multilocation production of end products), and the large quantity of nonpoint emission sources. The lack of consistent methodology of some impacts that are of major concern to agriculture (e.g., land use and water usage) increases the complexity of this analysis. This paper strives to review some of these issues and give perspective to the LCA practitioner in the field of agriculture. PMID:24391463

  5. High quality InSAR data linked to seasonal change in hydraulic head for an agricultural area in the San Luis Valley, Colorado

    NASA Astrophysics Data System (ADS)

    Reeves, Jessica A.; Knight, Rosemary; Zebker, Howard A.; Schreüder, Willem A.; Shanker Agram, Piyush; Lauknes, Tom R.

    2011-12-01

    In the San Luis Valley (SLV), Colorado legislation passed in 2004 requires that hydraulic head levels in the confined aquifer system stay within the range experienced in the years 1978-2000. While some measurements of hydraulic head exist, greater spatial and temporal sampling would be very valuable in understanding the behavior of the system. Interferometric synthetic aperture radar (InSAR) data provide fine spatial resolution measurements of Earth surface deformation, which can be related to hydraulic head change in the confined aquifer system. However, change in cm-scale crop structure with time leads to signal decorrelation, resulting in low quality data. Here we apply small baseline subset (SBAS) analysis to InSAR data collected from 1992 to 2001. We are able to show high levels of correlation, denoting high quality data, in areas between the center pivot irrigation circles, where the lack of water results in little surface vegetation. At three well locations we see a seasonal variation in the InSAR data that mimics the hydraulic head data. We use measured values of the elastic skeletal storage coefficient to estimate hydraulic head from the InSAR data. In general the magnitude of estimated and measured head agree to within the calculated error. However, the errors are unacceptably large due to both errors in the InSAR data and uncertainty in the measured value of the elastic skeletal storage coefficient. We conclude that InSAR is capturing the seasonal head variation, but that further research is required to obtain accurate hydraulic head estimates from the InSAR deformation measurements.

  6. Developing Earth Observations Requirements for Global Agricultural Monitoring

    NASA Astrophysics Data System (ADS)

    Whitcraft, A. K.; Becker-Reshef, I.; Vermote, E.; Justice, C. O.

    2013-12-01

    Recognizing the dynamic nature of agricultural cultivation both within and between years and across the globe, the Group on Earth Observations (GEO) is developing an agricultural monitoring (GEO-GLAM) system with the goal of enhancing the availability and use of satellite and in situ Earth observations (EO) for the generation of timely and accurate information on national, regional, and global food supply. One of the key components of the GEO-GLAM system is the coordination of satellite observations so as to ensure sufficient and appropriate data volume and quality for agricultural monitoring. Therefore, it is essential that we develop EO requirements which articulate in a spatially explicit way where, when, how frequently, and at what spatial resolution satellite imagery must be acquired to meet the needs of a variety of agricultural monitoring applications. Accordingly, best-available cropland location information ('where?') in conjunction with ten years of MODIS surface reflectance data have been used to characterize the timing and duration of the agricultural growing season ('when?') in the form of agricultural growing season calendars (GSCs) for all major agricultural areas of the Earth. With respect to temporal resolution, we must first identify the frequency with which we require imagery inputs for monitoring applications such as crop condition, crop type, crop yield estimation, and planted and harvested area estimation. Members of the GEO Agriculture Monitoring Community of Practice - a group of international scientists - have combined their knowledge and expertise to articulate these general requirements. Second, we must determine how cloud cover impacts the ability of optical sensing systems to meet these established temporal resolution requirements. To this end, MODIS Terra (morning; 2000-2011) and Aqua (afternoon; 2002-2011) observations have been analyzed to derive probabilities of a cloud free clear view at different times of day throughout the

  7. Agriculture drought risk assessment of the irrigated agriculture zone in North Henan Plain using HJ-1 and MODIS data

    NASA Astrophysics Data System (ADS)

    He, Haixia; Huang, He; Wang, Ping; Sun, Yinxiang

    2011-12-01

    This paper analyzed the evolution of drought and the spectral response of the crop at different growing seasons focuses on the irrigated agricultural areas of northen Henan using the HJ-1 data and MODIS data,associated with relevant meteologic data, regional geographical data and the social economic data.The Spatial and temporal distribution of the risk of disaster-causing factors and the fragility of the disaster-affected body was conducted and the comprehensive index of agricultral drought risk was built up.Then, trend of the agricultural drought was analyzed and the irrigated agricultural drought risk class was performed and the possible hazard and influence of agricultural drought and the performance of appropriate strategy to reduce agricultral drought have been estimated.At last,verification of the results and improvement of the model have been carried out supported by the historic cases, expert system and the on-site investigation data.

  8. Ecological and evolutionary implications of spatial heterogeneity during the off-season for a wild plant pathogen.

    PubMed

    Tack, Ayco J M; Laine, Anna-Liisa

    2014-04-01

    While recent studies have elucidated many of the factors driving parasite dynamics during the growing season, the ecological and evolutionary dynamics during the off-season (i.e. the period between growing seasons) remain largely unexplored. We combined large-scale surveys and detailed experiments to investigate the overwintering success of the specialist plant pathogen Podosphaera plantaginis on its patchily distributed host plant Plantago lanceolata in the Åland Islands. Twelve years of epidemiological data establish the off-season as a crucial stage in pathogen metapopulation dynamics, with c. 40% of the populations going extinct during the off-season. At the end of the growing season, we observed environmentally mediated variation in the production of resting structures, with major consequences for spring infection at spatial scales ranging from single individuals to populations within a metapopulation. Reciprocal transplant experiments further demonstrated that pathogen population of origin and overwintering site jointly shaped infection intensity in spring, with a weak signal of parasite adaptation to the local off-season environment. We conclude that environmentally mediated changes in the distribution and evolution of parasites during the off-season are crucial for our understanding of host-parasite dynamics, with applied implications for combating parasites and diseases in agriculture, wildlife and human disease systems. PMID:24372358

  9. Viewing Seasonality in 8 Megacities at 4 Microns

    NASA Astrophysics Data System (ADS)

    Tomaszewska, M. A.; Kovalskyy, V.; Small, C.; Henebry, G. M.

    2013-12-01

    months and quite low in the winter months at high latitudes, as was expected due to the seasonal cycle of irradiance. The urban land cover showed higher seasonal dynamic range than most other cover types, with the forest 'natural' type showing least seasonal variation and agriculture showing more variation than forest but less than urban. Where the 'natural' type included much exposed soil or dried vegetation (savanna near Nairobi and New Delhi or desert near Cairo), the seasonal dynamic range in the MIR exceeded that of the associated city. However, the interaction of VZA and seasonality was most evident in the agricultural land covers, likely due to exposed cropland soils being gradually covered by the growing canopy when viewed at higher VZAs.

  10. Waiting for trees to grow: nest survival, brood parasitism, and the impact of reforestation efforts

    USGS Publications Warehouse

    Hazler, K.R.; Twedt, D.J.; Cooper, R.J.

    2005-01-01

    Of the forested wetlands that once covered the Mississippi Alluvial Valley, only -25% remain due to large-scale conversion to agriculture. Reforestation efforts are currently underway, but tracts planted with slow-growing oaks maintain the structure of a grassland for 5 yr or longer, and will require at least 40 yr to resemble a mature forest. Nonetheless, it is hoped that reforestation, even in early stages, can effectively increase core area in extant tracts of mature forest by reducing higher rates of nest failure and brood parasitism often associated with forest-agriculture interfaces. To test this, we monitored nests of a mature-forest specialist, the Acadian Flycatcher, in extensive bottomland forests adjacent to agricultural fields and reforested tracts (<20 yr-old). We used an information-theoretic approach to evaluate alternative hypotheses regarding the relative impacts of agriculture and reforestation in the landscape. Controlling for year, season, and stand basal area, there was little evidence that landscape context significantly affected nest survival, although survival tended to increase with decreasing amounts of agriculture. The probability of brood parasitism increased with greater proportions of open habitats in the landscape. There was much stronger support for the hypothesis that parasitism rates depended on the sum of agricultural and reforested tracts, rather than on the amount of agriculture alone. Thus, reforested tracts are not expected to have the desired effect of reducing parasitism rates in the adjacent mature forest until several decades have passed.

  11. Growing and Growing: Promoting Functional Thinking with Geometric Growing Patterns

    ERIC Educational Resources Information Center

    Markworth, Kimberly A.

    2010-01-01

    Design research methodology is used in this study to develop an empirically-substantiated instruction theory about students' development of functional thinking in the context of geometric growing patterns. The two research questions are: (1) How does students' functional thinking develop in the context of geometric growing patterns? (2) What are…

  12. Agriculture Education. Agriculture Structures.

    ERIC Educational Resources Information Center

    Stuttgart Public Schools, AR.

    This curriculum guide is designed for group instruction of secondary agricultural education students enrolled in one or two semester-long courses in agriculture structures. The guide presents units of study in the following areas: (1) shop safety, (2) identification and general use of hand tools, (3) power tools, (4) carpentry, (5) blueprint…

  13. A Farming Revolution: Sustainable Agriculture.

    ERIC Educational Resources Information Center

    Klinkenborg, Verlyn

    1995-01-01

    Growing realization of the economic, social, and environmental costs of conventional agriculture has led many U.S. farmers to embrace and become advocates for agricultural practices that limit the need for pesticides and chemical fertilizers, decrease soil erosion, and improve soil health. Some hope that sustainable agriculture can promote smaller…

  14. 1971 Post Season Rural Manpower Report.

    ERIC Educational Resources Information Center

    Michigan State Dept. of Labor, Detroit. Michigan Employment Security Commission.

    The Rural Manpower Service reports on the migrant seasonal labor in Michigan during 1971. Seasonal labor has been declining since it reached its peak of 97,700 in 1962. This report discusses migrant seasonal labor with regard to (1) the wages and earnings of the workers, (2) the recruitment of workers, (3) the agricultural-labor housing, (4) the…

  15. Agricultural activity shapes the communication and migration patterns in Senegal.

    PubMed

    Martin-Gutierrez, S; Borondo, J; Morales, A J; Losada, J C; Tarquis, A M; Benito, R M

    2016-06-01

    The communication and migration patterns of a country are shaped by its socioeconomic processes. The economy of Senegal is predominantly rural, as agriculture employs over 70% of the labor force. In this paper, we use mobile phone records to explore the impact of agricultural activity on the communication and mobility patterns of the inhabitants of Senegal. We find two peaks of phone calls activity emerging during the growing season. Moreover, during the harvest period, we detect an increase in the migration flows throughout the country. However, religious holidays also shape the mobility patterns of the Senegalese people. Hence, in the light of our results, agricultural activity and religious holidays are the primary drivers of mobility inside the country. PMID:27368795

  16. Agricultural activity shapes the communication and migration patterns in Senegal

    NASA Astrophysics Data System (ADS)

    Martin-Gutierrez, S.; Borondo, J.; Morales, A. J.; Losada, J. C.; Tarquis, A. M.; Benito, R. M.

    2016-06-01

    The communication and migration patterns of a country are shaped by its socioeconomic processes. The economy of Senegal is predominantly rural, as agriculture employs over 70% of the labor force. In this paper, we use mobile phone records to explore the impact of agricultural activity on the communication and mobility patterns of the inhabitants of Senegal. We find two peaks of phone calls activity emerging during the growing season. Moreover, during the harvest period, we detect an increase in the migration flows throughout the country. However, religious holidays also shape the mobility patterns of the Senegalese people. Hence, in the light of our results, agricultural activity and religious holidays are the primary drivers of mobility inside the country.

  17. Variability of growing degree days in Poland in response to ongoing climate changes in Europe

    NASA Astrophysics Data System (ADS)

    Wypych, Agnieszka; Sulikowska, Agnieszka; Ustrnul, Zbigniew; Czekierda, Danuta

    2016-05-01

    An observed increase in air temperature can lead to significant changes in the phenology of plants and, consequently, changes in agricultural production. The aim of the study was to evaluate the spatial differentiation of thermal resources in Poland and their variability during a period of changing thermal conditions in Europe. Since the variability of thermal conditions is of paramount importance for perennial crops, the study focused on apple, plum, and cherry orchard regions in Poland. The analysis was conducted for the period of 1951-2010 using air temperature daily data. Thermal resources have been defined using the growing degree days (GDD) index calculated independently for the whole year and during in frost-free season for three air temperature thresholds: 0, 5, and 10 °C, which determine the non-winter period, growing season, and the period of full plant growth, respectively. In addition, due to the high significance for perennials in particular, the incidence and intensity of frost during flowering were calculated. In this study, a detailed analysis of the spatial differentiation of thermal resources was first performed, followed by an evaluation of long-term variability and associated change patterns. The obtained results confirmed an increase in thermal resources in Poland as a consequence of the lengthening of the growing season. However, the frequency and intensity of spring frost, especially during flowering or even during ripening of plants, remain a threat to harvests in both the eastern and western parts of the country.

  18. Phone traffic as a measurement of agricultural events

    NASA Astrophysics Data System (ADS)

    Martín, Samuel; Borondo, Javier; Morales, Alfredo; Losada, Juan Carlos; Tarquis, Ana M.; Benito, Rosa Maria

    2015-04-01

    Inspired by empirical studies of networked systems such as the Internet, social networks, and biological networks, researchers have in recent years developed a variety of techniques and models to help us understand or predict the behaviour of these systems (1). However, it has been recently when global food system has been seen as a complex web of production, processing, storage and transportation opening new challenges in their analysis. Agricultural activities in developing countries remain as important today as in the 1950s implying seasonal workers mobilization. The proliferation of mobile phones (MPs) offers an unprecedented tool to analyze human activity mapping. We would like to mention that in developed countries, the number of MP subscribers has surpassed the total population, with a penetration rate now reaching 121%, whereas in developing countries, it is as high as 90% and continuing to rise (2). As an example, we have analyzed the impact that agricultural activities, such as the growing of groundnut, have on Senegal. To this end we have analyzed the Normalized Difference Vegetation Index (NDVI) time series of the whole of Senegal and spotted the regions where groundnut is grown to identify the time period when this crop growth. By analyzing phone calls at each region of the country we found that a significant fraction of antennas exhibit two well defined peaks of activity corresponding with the begging and end of the growing season. Antennas located on regions identified as growing regions present this pattern. However, other antennas, located in non growing regions, such as Dakar, also present the two peaks pattern pointing out the synchronization between growing regions and key points in cities that emerges from the agricultural activity. References 1. Marta C. González, César A. Hidalgo and Albert-László Barabási (2008) Understanding individual human mobility patterns. Nature 453, 779-78. 2. International Telecommunication Union (2014) World

  19. Seasonal Phenology and Species Composition of the Aphid Fauna in a Northern Crop Production Area

    PubMed Central

    Kirchner, Sascha M.; Hiltunen, Lea; Döring, Thomas F.; Virtanen, Elina; Palohuhta, Jukka P.; Valkonen, Jari P. T.

    2013-01-01

    Background The species diversity of aphids and seasonal timing of their flight activity can have significant impacts on crop production, as aphid species differ in their ability to transmit plant viruses and flight timing affects virus epidemiology. The aim of the study was to characterise the species composition and phenology of aphid fauna in Finland in one of the northernmost intensive crop production areas of the world (latitude 64°). Methodology/Principal Findings Flight activity was monitored in four growing seasons (2007–010) using yellow pan traps (YPTs) placed in 4–8 seed potato fields and a Rothamsted suction trap. A total of 58,528 winged aphids were obtained, identified to 83 taxa based on morphology, and 34 species were additionally characterised by DNA barcoding. Seasonal flight activity patterns analysed based on YPT catch fell into three main phenology clusters. Monoecious taxa showed early or middle-season flight activity and belonged to species living on shrubs/trees or herbaceous plants, respectively. Heteroecious taxa occurred over the entire potato growing season (ca. 90 days). Abundance of aphids followed a clear 3-year cycle based on suction trap data covering a decade. Rhopalosiphum padi occurring at the end of the potato growing season was the most abundant species. The flight activity of Aphis fabae, the main vector of Potato virus Y in the region, and Aphis gossypii peaked in the beginning of potato growing season. Conclusions/Significance Detailed information was obtained on phenology of a large number aphid species, of which many are agriculturally important pests acting as vectors of plant viruses. Aphis gossypii is known as a pest in greenhouses, but our study shows that it occurs also in the field, even far in the north. The novel information on aphid phenology and ecology has wide implications for prospective pest management, particularly in light of climate change. PMID:23967149

  20. Background levels of some major, trace, and rare earth elements in indigenous plant species growing in Norway and the influence of soil acidification, soil parent material, and seasonal variation on these levels.

    PubMed

    Gjengedal, Elin; Martinsen, Thomas; Steinnes, Eiliv

    2015-06-01

    Baseline levels of 43 elements, including major, trace, and rare earth elements (REEs) in several native plant species growing in boreal and alpine areas, are presented. Focus is placed on species metal levels at different soil conditions, temporal variations in plant tissue metal concentrations, and interspecies variation in metal concentrations. Vegetation samples were collected at Sogndal, a pristine site in western Norway, and at Risdalsheia, an acidified site in southernmost Norway. Metal concentrations in the different species sampled in western Norway are compared with relevant literature data from Norway, Finland, and northwest Russia, assumed to represent natural conditions. Except for aluminium (Al) and macronutrients, the levels of metals were generally lower in western Norway than in southern Norway and may be considered close to natural background levels. In southern Norway, the levels of cadmium (Cd) and lead (Pb) in particular appear to be affected by air pollution, either by direct atmospheric supply or through soil acidification. Levels of some elements show considerable variability between as well as within plant species. Calcium (Ca), magnesium (Mg), and potassium (K) are higher in most species at Sogndal compared to Risdalsheia, despite increased extractable concentrations in surface soil in the south, probably attributed to different buffer mechanisms in surface soil. Antagonism on plant uptake is suggested between Ca, Mg, and K on one hand and Al on the other. Tolerance among calcifuges to acid conditions and a particular ability to detoxify or avoid uptake of Al ions are noticeable for Vaccinium vitis-idaea. PMID:26022847

  1. Assessing the Remotely Sensed Drought Severity Index for Agricultural Drought Monitoring in North China

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Huang, J.; Mu, Q.

    2014-12-01

    With a warming climate, the world has experienced frequent droughts during the past few decades. A remotely sensed Drought Severity Index (DSI), which integrates both vegetation growth condition and evapotranspiration, has been recently proposed for drought monitoring at the global scale. However, there has been little research on its utility for regional application, especially on agricultural drought. As an important winter wheat producing region, the North China has suffered from frequent droughts in recent years. In this study, the capability of the DSI for drought monitoring and impact analysis in five wheat producing provinces of North China was investigated. First, the DSI was compared with precipitation and soil moisture to show its ability for characterizing moisture status. Then specifically for agricultural drought, the DSI was evaluated against agricultural drought severity and the impacts of drought on crop yield during the growing season were also explored using the 8-day DSI data. The main conclusions are: (1) The DSI shows generally good ability for characterizing moisture conditions at the province level with varying ability during winter wheat main growing season (March-June), and the best relationship was found in April. (2) Despite varying capability, the DSI is quite effective in characterizing agricultural drought severity at the province level. (3) Drought shows generally increasing agricultural impacts during winter wheat main growing season (March-June), with little impacts in March (green-up stage), emerging impacts in April (jointing and booting stages) and significant drought impacts in May (heading and filling stages). (4) Based on the spatial pattern of agricultural drought impacts, densely winter wheat planted areas such as South Hebei, Central/West Shandong and North/East Henan are identified as drought vulnerable regions and comprehensive monitoring in these hotspots is highly recommended.

  2. Growing plants on atoll soils

    SciTech Connect

    Stone, E L; Migvar, L; Robison, W L

    2000-02-16

    year. Except on the driest of atolls, air temperature and humidity range only within limits set by the surrounding sea. There are no cold seasons, no frosts, no cold soils, no dry winds, and no periodic plagues of insects or diseases moving from miles away. Problems of soil drainage or salinity are few and easily recognized. Nor are there problems with acid soils, soil crusting, or erosion that challenge cultivators in many other areas. On the contrary, some of the black soils at the center of wide islands rank with the best soils of Russia and the American Midwest, except for their shortage of potassium and the uncertainties of rainfall. Some of these atoll soils contain more total nitrogen than many of the world's most productive agricultural soils and, in some, the total phosphorus content is so high as to be almost unbelievable--two to five tons of the element per acre. Certainly, problems exist in growing plants on atolls. There are also some special concerns not encountered in other environments, such as the wind and salt spray near shore. The two major physical limitations, however, are inadequate rainfall in some years and in many places, and soil fertility limitations. The alkaline or ''limy'' make-up of atoll soils means that a few plant nutrients, especially iron, limit growth of many introduced plants, and this is difficult to correct. As elsewhere in the world, many--but not all--atoll soils lack enough nitrogen and/or phosphorus for high yield, and all lack sufficient potassium. There is no practical way of overcoming drought except by use of tolerant plants such as coconut (ni) and Pandanus (bob), plus collection and careful use of whatever water is available. There are opportunities to overcome nutritional limitations mentioned above, first, by intensive use of all organic debris and household wastes in small gardens and, second, by use of commercial fertilizers. Imported fertilizers are expensive, certainly, but much less so on a family basis than the

  3. Changing Seasons

    ERIC Educational Resources Information Center

    Karolak, Eric

    2011-01-01

    In some ways, there is a season of change at the national level in early childhood. Some things are wrapping up while some developments aim to prepare the "field" for improvements in the next year and beyond, just as a garden plot is readied for the next planting season. Change is in the air, and there's hope of renewal, but what changes and how…

  4. Spectrally-Based Assessment of Crop Seasonal Performance and Yield

    NASA Astrophysics Data System (ADS)

    Kancheva, Rumiana; Borisova, Denitsa; Georgiev, Georgy

    The rapid advances of space technologies concern almost all scientific areas from aeronautics to medicine, and a wide range of application fields from communications to crop yield predictions. Agricultural monitoring is among the priorities of remote sensing observations for getting timely information on crop development. Monitoring agricultural fields during the growing season plays an important role in crop health assessment and stress detection provided that reliable data is obtained. Successfully spreading is the implementation of hyperspectral data to precision farming associated with plant growth and phenology monitoring, physiological state assessment, and yield prediction. In this paper, we investigated various spectral-biophysical relationships derived from in-situ reflectance measurements. The performance of spectral data for the assessment of agricultural crops condition and yield prediction was examined. The approach comprisesd development of regression models between plant spectral and state-indicative variables such as biomass, vegetation cover fraction, leaf area index, etc., and development of yield forecasting models from single-date (growth stage) and multitemporal (seasonal) reflectance data. Verification of spectral predictions was performed through comparison with estimations from biophysical relationships between crop growth variables. The study was carried out for spring barley and winter wheat. Visible and near-infrared reflectance data was acquired through the whole growing season accompanied by detailed datasets on plant phenology and canopy structural and biochemical attributes. Empirical relationships were derived relating crop agronomic variables and yield to various spectral predictors. The study findings were tested using airborne remote sensing inputs. A good correspondence was found between predicted and actual (ground-truth) estimates

  5. Challenge for future agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Future food security will be dependent upon a combination of the stresses imposed by climate change, variability of weather within the growing season, development of cultivars more suited to different conditions, and the ability to develop effective adaptation strategies which allow these cultivars ...

  6. From LACIE to GEOGLAM: Integrating Earth Observations into Operational Agricultural Monitoring Systems

    NASA Astrophysics Data System (ADS)

    Becker-Reshef, I.; Justice, C. O.

    2012-12-01

    Earth observation data, owing to their synoptic, timely and repetitive coverage, have long been recognized as an indispensible tool for agricultural monitoring at local to global scales. Research and development over the past several decades in the field of agricultural remote sensing has led to considerable capacity for crop monitoring within the current operational monitoring systems. These systems are relied upon nationally and internationally to provide crop outlooks and production forecasts as the growing season progresses. This talk will discuss the legacy and current state of operational agricultural monitoring using earth observations. In the US, the National Aeronautics and Space Administration (NASA) and the US Department of Agriculture (USDA) have been collaborating to monitor global agriculture from space since the 1970s. In 1974, the USDA, NASA and National Oceanic and Atmospheric Administration (NOAA) initiated the Large Area Crop Inventory Experiment (LACIE) which demonstrated that earth observations could provide vital information on crop production, with unprecedented accuracy and timeliness, prior to harvest. This experiment spurred many agencies and researchers around the world to further develop and evaluate remote sensing technologies for timely, large area, crop monitoring. The USDA and NASA continue to closely collaborate. More recently they jointly initiated the Global Agricultural Monitoring Project (GLAM) to enhance the agricultural monitoring and the crop-production estimation capabilities of the USDA Foreign Agricultural Service by using the new generation of NASA satellite observations including from MODIS and the Visible Infrared Imaging Radiometer Suite (VIIRS) instruments. Internationally, in response to the growing calls for improved agricultural information, the Group on Earth Observations (partnership of governments and international organizations) developed the Global Agricultural Monitoring (GEOGLAM) initiative which was adopted

  7. Skilling a Seasonal Workforce: A Way Forward for Rural Regions

    ERIC Educational Resources Information Center

    Kilpatrick, Sue; Bound, Helen

    2005-01-01

    Seasonal work is crucial for the many rural regions reliant on seasonal industries such as agriculture, forestry, aquaculture and tourism. This report examines the diverse nature of the seasonal workforce in two locations and the approaches used in their training. The report finds that the seasonal workforce is diverse and has varied training…

  8. Direct human influence on atmospheric CO2 seasonality from increased cropland productivity

    NASA Astrophysics Data System (ADS)

    Gray, Josh M.; Frolking, Steve; Kort, Eric A.; Ray, Deepak K.; Kucharik, Christopher J.; Ramankutty, Navin; Friedl, Mark A.

    2014-11-01

    Ground- and aircraft-based measurements show that the seasonal amplitude of Northern Hemisphere atmospheric carbon dioxide (CO2) concentrations has increased by as much as 50 per cent over the past 50 years. This increase has been linked to changes in temperate, boreal and arctic ecosystem properties and processes such as enhanced photosynthesis, increased heterotrophic respiration, and expansion of woody vegetation. However, the precise causal mechanisms behind the observed changes in atmospheric CO2 seasonality remain unclear. Here we use production statistics and a carbon accounting model to show that increases in agricultural productivity, which have been largely overlooked in previous investigations, explain as much as a quarter of the observed changes in atmospheric CO2 seasonality. Specifically, Northern Hemisphere extratropical maize, wheat, rice, and soybean production grew by 240 per cent between 1961 and 2008, thereby increasing the amount of net carbon uptake by croplands during the Northern Hemisphere growing season by 0.33 petagrams. Maize alone accounts for two-thirds of this change, owing mostly to agricultural intensification within concentrated production zones in the midwestern United States and northern China. Maize, wheat, rice, and soybeans account for about 68 per cent of extratropical dry biomass production, so it is likely that the total impact of increased agricultural production exceeds the amount quantified here.

  9. Direct human influence on atmospheric CO2 seasonality from increased cropland productivity.

    PubMed

    Gray, Josh M; Frolking, Steve; Kort, Eric A; Ray, Deepak K; Kucharik, Christopher J; Ramankutty, Navin; Friedl, Mark A

    2014-11-20

    Ground- and aircraft-based measurements show that the seasonal amplitude of Northern Hemisphere atmospheric carbon dioxide (CO2) concentrations has increased by as much as 50 per cent over the past 50 years. This increase has been linked to changes in temperate, boreal and arctic ecosystem properties and processes such as enhanced photosynthesis, increased heterotrophic respiration, and expansion of woody vegetation. However, the precise causal mechanisms behind the observed changes in atmospheric CO2 seasonality remain unclear. Here we use production statistics and a carbon accounting model to show that increases in agricultural productivity, which have been largely overlooked in previous investigations, explain as much as a quarter of the observed changes in atmospheric CO2 seasonality. Specifically, Northern Hemisphere extratropical maize, wheat, rice, and soybean production grew by 240 per cent between 1961 and 2008, thereby increasing the amount of net carbon uptake by croplands during the Northern Hemisphere growing season by 0.33 petagrams. Maize alone accounts for two-thirds of this change, owing mostly to agricultural intensification within concentrated production zones in the midwestern United States and northern China. Maize, wheat, rice, and soybeans account for about 68 per cent of extratropical dry biomass production, so it is likely that the total impact of increased agricultural production exceeds the amount quantified here. PMID:25409830

  10. Environmental Impacts of the Annual Agricultural Drawdown in Southern Miami-Dade County

    NASA Astrophysics Data System (ADS)

    Kearns, E. J.; Renshaw, A.; Bellmund, S.

    2008-05-01

    Water managers annually manipulate groundwater storage in Southern Miami-Dade County at the end of the wet season to support agricultural interests. The so-called "agricultural drawdown" in Southern Miami-Dade County involves a 0.8 ft (0.24 m) reduction in groundwater stages via the release of large volumes of water each fall to Biscayne Bay. An average of 21.4 billion gallons (65,800 ac-ft or 8.1x107 m3) of freshwater are released each year from the Biscayne Aquifer via the C-103 and C-102 canals during the drawdown in anticipation of the winter growing season. The side-effects of this groundwater drawdown and loss of stored water are felt primarily by the environment in, and adjacent to, southern Biscayne Bay. Without the rapid drainage of freshwater, these large volumes of water would gradually leak into Biscayne Bay and its low-lying coastal wetlands, providing freshwater flows further into the dry season. The rapid and sudden release of water from the Biscayne Aquifer within a few weeks of the end of the wet season brings about an artificially early start to the dry season. The following dry season is thus unnaturally dry, leading to long periods of dry marshes and high salinities along the shoreline. The result threatens productive estuarine fish and shellfish habitat, enhances predation of nearshore species by marine fish, encourages exotic plant species within the coastal wetland zone, and promotes a loss of wading bird foraging habitat during nesting season. The threat of saltwater intrusion into the Biscayne Aquifer is enhanced by this operational practice as well, since sea levels are at their seasonal maximums in October and November. The effects of the agricultural drawdown, the possible enhancements to the coastal ecosystem that could be realized by its elimination, and its future within the context of the Comprehensive Everglades Restoration Plan's Biscayne Bay Coastal Wetlands project will be explored.

  11. INNOVATIVE USES OF VEGETATED DRAINAGE DITCHES FOR REDUCING AGRICULTURAL RUNOFF

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growing concerns over agricultural contributions to water quality degradation have resulted in increased emphasis on discovering new, innovative best management practices (BMPs) to decrease effects of storm water runoff containing potential agricultural pollutants. Vegetated agricultural ditches pla...

  12. Nitrate isotopes unveil distinct seasonal N-sources and the critical role of crop residues in groundwater contamination

    NASA Astrophysics Data System (ADS)

    Savard, Martine M.; Somers, George; Smirnoff, Anna; Paradis, Daniel; van Bochove, Eric; Liao, Shawna

    2010-02-01

    SummaryGlobally, fertilizers are identified as principle sources of nitrate in waters of intensely cultivated areas. Here this general concept is appraised on a seasonal basis over a two year period, under temperate climatic conditions. Water ( δ2H and δ18O) and nitrate ( δ15N and δ18O) isotopes in surface water and groundwater suggest that freshwater is acting as a transport vector conducting nitrate from agricultural soils to groundwater and ultimately to surface water. Measured nitrate isotopes of organic and inorganic fertilizers and of nitrate in groundwater are used to constrain a conceptual apportionment model quantifying the relative seasonal N contributions in an area of intense potato production. Source inputs differ strongly between the growing (summer and fall) and non-growing (winter and spring) periods. Chemical fertilizers and soil organic matter equally dominate and contribute to the growing period load, whereas soil organic matter dominates the non-growing period load, and accounts for over half of the overall annual nitrogen charge. These findings reveal the magnitude of nitrogen cycling by soil organic matter, and point to the benefits of controlling the timing of its nitrate release from this organic material. We conclude that strategies to attenuate contamination by nitrate in waters of temperate climate row-cropping regions must consider nitrogen cycling by soil organic matter, including the crucial role of crop residues throughout both the growing and non-growing seasons.

  13. Performance of Seasonally and Continuously Loaded Constructed Wetlands Treating Dairy Farm Wastewater.

    PubMed

    Wood, Jeffrey D; Gordon, Robert J; Madani, Ali; Stratton, Glenn W; Bromley, Heather M

    2015-11-01

    A 2-yr study compared the performance of seasonally and continuously loaded constructed wetlands treating dairy farm wastewater. One wetland was loaded during the growing season (GS) periods only, while the other was continuously loaded. Weekly samples were analyzed for 5-d biochemical oxygen demand (BOD), total suspended solids (TSS), total Kjeldahl N (TKN), total ammoniacal N (TAN), total P (TP), and . Annual average daily mass removal rates (kg ha) were similar for both wetlands in both years; however, seasonal differences were observed. With the exception of BOD in Year 2, average daily GS areal mass removal rates were higher for the seasonal wetland. However, GS mass exports from the seasonal wetland were higher by 28 to 94%, with the exception of BOD in Year 1. Annual mass reductions (MRs; %) for nutrients were higher for the continuous wetland in both years. Annual MRs were similar for in both years and for TSS in Year 2. Annual mass exports from the seasonal wetland were higher for nutrients and by 14 to 77% in both years. Pollutant MRs generally decreased during the nongrowing season (NGS) for the continuous wetland; however, in Year 2 when lower loading rates were used, the wetland still removed 84 to 99% of the pollutant masses. The continuous wetland also performed better during periods of high flow that occurred during the GS. Although there were minimal differences in annual treatment performance, continuously loaded systems require less additional infrastructure and should require less maintenance and may, therefore, be more attractive for agricultural applications. PMID:26641349

  14. Mercury Cycling in Agricultural and Non-agricultural Wetlands of the Yolo Bypass Wildlife Area, California: Sediment Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Marvin-Dipasquale, M. C.; Windham-Myers, L.; Alpers, C. N.; Agee, J. L.; Cox, M. H.; Kakouros, E.; Wren, S. L.

    2007-12-01

    The Yolo Bypass Wildlife Area (YBWA) is part of the larger Yolo Bypass floodwater protection zone associated with the Sacramento River and the Sacramento-San Joaquin Delta, California. Land use in the YBWA consists of white and wild rice fields, seasonally flooded fallow agricultural fields, and permanently and seasonally flooded non-agricultural wetlands used for resident and migratory waterfowl. A recent assessment of mercury (Hg) and methylmercury (MeHg) loads indicates that the Yolo Bypass is responsible for a high proportion of the aqueous MeHg entering the Delta, and that biota from the Yolo Bypass are considerably elevated in MeHg. The current study examines benthic MeHg production and biogeochemical controls on this process, as a function of YBWA land use, wetland management, and agricultural practices during the 2007 rice growing season (June to October). Preliminary results indicate that in the week following initial flooding of agricultural fields, prior to the establishment of rice plants, the microbial community in the 0-2 cm surface sediment zone exhibited very little potential Hg(II)-methylation activity compared to the permanent wetland habitat (as assessed via the 203Hg(II)- methylation assay). Approximately 1 month after flooding, rice plants were established and the activity of the resident Hg(II)-methylating microbial community had increased substantially in all agricultural fields, although the observed rates of MeHg production were still much lower than those observed in the permanent wetland setting. Ongoing field sampling includes analysis of reactive Hg(II) in sediments and of iron and sulfur redox species in sediments and pore waters.

  15. Guidelines for growing perennial grasses for biofuel and bioproducts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Guidelines for growing perennial grasses for biofuel and bioproducts Rob Mitchell Abstract: Switchgrass, big bluestem, and warm-season grass mixtures provide numerous benefits. Existing field equipment, herbicides, and cultivar improvement promote rapid establishment in the planting year. These gra...

  16. Preliminary assessment of off-season fuels for electricity generation at Indian sugar mills

    SciTech Connect

    Perlack, R.D.; Ranney, J.W.

    1995-11-07

    This report on off-season fuels is part of a preliminary feasibility assessment to retrofit Indian sugar mills to cogenerate heat and power with sales of excess electricity to the local grid. To justify the high capital costs of retrofitting existing facilities, sugar mill operators must attempt to maximize the amount of power they sell to the local grid. This fact means that sugar mills must operate and sell power well-beyond the milling season, which typically lasts about 200 days. The purpose of this report is to assess and determine whether low cost and reliable sources of off-season fuels can be secured for two sugar mills (Simbhaoli and Daurala) within their respective sugar growing districts, located in western Uttar Pradesh. Off-season fuels under consideration include excess bagasse that is stored for off-season use, agricultural field residues (e.g., wheat straw), forest residues (e.g., bark and small limbs), and dedicated energy crops (short-rotation woody crops and herbaceous energy crops). Results of the pre-feasibility indicate that bagasse and some agricultural residues are available in sufficient quantity and may be available at reasonable cost.

  17. Linking seasonal climate forecasts with crop models in Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Capa, Mirian; Ines, Amor; Baethgen, Walter; Rodriguez-Fonseca, Belen; Han, Eunjin; Ruiz-Ramos, Margarita

    2015-04-01

    Translating seasonal climate forecasts into agricultural production forecasts could help to establish early warning systems and to design crop management adaptation strategies that take advantage of favorable conditions or reduce the effect of adverse conditions. In this study, we use seasonal rainfall forecasts and crop models to improve predictability of wheat yield in the Iberian Peninsula (IP). Additionally, we estimate economic margins and production risks associated with extreme scenarios of seasonal rainfall forecast. This study evaluates two methods for disaggregating seasonal climate forecasts into daily weather data: 1) a stochastic weather generator (CondWG), and 2) a forecast tercile resampler (FResampler). Both methods were used to generate 100 (with FResampler) and 110 (with CondWG) weather series/sequences for three scenarios of seasonal rainfall forecasts. Simulated wheat yield is computed with the crop model CERES-wheat (Ritchie and Otter, 1985), which is included in Decision Support System for Agrotechnology Transfer (DSSAT v.4.5, Hoogenboom et al., 2010). Simulations were run at two locations in northeastern Spain where the crop model was calibrated and validated with independent field data. Once simulated yields were obtained, an assessment of farmer's gross margin for different seasonal climate forecasts was accomplished to estimate production risks under different climate scenarios. This methodology allows farmers to assess the benefits and risks of a seasonal weather forecast in IP prior to the crop growing season. The results of this study may have important implications on both, public (agricultural planning) and private (decision support to farmers, insurance companies) sectors. Acknowledgements Research by M. Capa-Morocho has been partly supported by a PICATA predoctoral fellowship of the Moncloa Campus of International Excellence (UCM-UPM) and MULCLIVAR project (CGL2012-38923-C02-02) References Hoogenboom, G. et al., 2010. The Decision

  18. Estimated demand for agricultural water for irrigation use in New Jersey, 1990

    USGS Publications Warehouse

    Titus, E.O.; Clawges, R.M.; Qualls, C.L.

    1990-01-01

    As part of an effort to determine if an adequate supply of agricultural water for irrigation use will be available to farmers, the U.S. Geological Survey prepared preliminary estimates of demand for agricultural water for irrigation use for the year 1990 on the basis of six possible scenarios. These scenarios incorporate normal and drought climatic conditions and three alternative estimates of the total acreage of farmland that may be irrigated in 1990. Preliminary estimates of water demand based on soil-moisture deficits were made using methods for calculating climatic water budgets. These estimates ranged from 3.0 billion gal/growing season (May through September), under normal climatic conditions and a 2% annual decline in irrigated acreage since 1984, to 28. 9 billion gal/growing season, under drought conditions and a 2% annual increase in irrigated acreage since 1984. Preliminary estimates of water demand made for the 1986 growing season reasonably approximate reported water use for that period. (USGS)

  19. Growing Pains (For Parents)

    MedlinePlus

    ... Joints affected by more serious diseases are swollen, red, tender, or warm — the joints of kids having growing pains look normal. Although growing pains often strike in late afternoon or early evening before bed, pain can sometimes wake a sleeping child. The ...

  20. Site Description for the University of Nebraska's Sandhills Agricultural Laboratory

    NASA Technical Reports Server (NTRS)

    Gardner, B. R.; Blad, B. L.

    1985-01-01

    The Sandhills Agricultural Laboratory is operated by the University of Nebraska. The laboratory is located in the south-central part of the Nebraska Sandhills near Tryon, Nebraska (41 deg. 37' N; 100 deg. 50' W). The laboratory is surrounded on the west and south by native rangeland vegetation, on the south by a large field of corn irrigated by a center pivot, and on the east by wheat stubble. This site is appropriate for moisture stress studies since rainfall is almost always inadequate to meet evaporative demands of agricultural crops during most of the growing season and the sandy soils (Valentine fine sand) at the site do not store large quantities of water. Various levels of water stress are achieved through irrigation from solid set sprinklers.

  1. Probabilistic Description of the Hydrologic Risk in Agriculture

    NASA Astrophysics Data System (ADS)

    Vico, G.; Porporato, A. M.

    2011-12-01

    Supplemental irrigation represents one of the main strategies to mitigate the effects of climatic variability on agroecosystems productivity and profitability, at the expenses of increasing water requirements for irrigation purposes. Optimizing water allocation for crop yield preservation and sustainable development needs to account for hydro-climatic variability, which is by far the main source of uncertainty affecting crop yields and irrigation water requirements. In this contribution, a widely applicable probabilistic framework is proposed to quantitatively define the hydrologic risk of yield reduction for both rainfed and irrigated agriculture. The occurrence of rainfall events and irrigation applications are linked probabilistically to crop development during the growing season. Based on these linkages, long-term and real-time yield reduction risk indices are defined as a function of climate, soil and crop parameters, as well as irrigation strategy. The former risk index is suitable for long-term irrigation strategy assessment and investment planning, while the latter risk index provides a rigorous probabilistic quantification of the emergence of drought conditions during a single growing season. This probabilistic framework allows also assessing the impact of limited water availability on crop yield, thus guiding the optimal allocation of water resources for human and environmental needs. Our approach employs relatively few parameters and is thus easily and broadly applicable to different crops and sites, under current and future climate scenarios, thus facilitating the assessment of the impact of increasingly frequent water shortages on agricultural productivity, profitability, and sustainability.

  2. Energy-efficient agriculture using aeroponics. Final report

    SciTech Connect

    Lederer, G.P.; Zobel, R.W.; Matthews, L.

    1994-01-01

    In New York State, the production of fresh vegetables and fruits in controlled environments, e.g., greenhouses and warehouses, could experience explosive growth, based on market opportunities resulting from water quality problems in major vegetable-growing states and Controlled Environment Agriculture (CEA) technological advancements in the Northeast and overseas for vegetable and ornamental crop production. CEA crops will be consistently high quality, will be available out-of-season, and potentially could be grown pesticide-free. Out-of-season, fresh vegetable markets for such CEA crops as lettuce and tomatoes are dominated by foreign producers with almost no New York output. The objective of this project was to develop a proprietary ultrasonic-mist generator capable of providing nutrient-laden mist to the roots of plants growing on Lederer Nursery, Inc.`s plant holding A-frame modules. This system of aeroponic agriculture suspends the plant`s roots in nutrient-laden air rather than soil or water.

  3. Extreme temperature trends in major cropping systems and their relation to agricultural land use change

    NASA Astrophysics Data System (ADS)

    Mueller, N. D.; Butler, E. E.; McKinnon, K. A.; Rhines, A. N.; Tingley, M.; Siebert, S.; Holbrook, N. M.; Huybers, P. J.

    2015-12-01

    High temperature extremes during the growing season can reduce agricultural production. At the same time, agricultural practices can modify temperatures by altering the surface energy budget. Here we investigate growing season climate trends in major cropping systems and their relationship with agricultural land use change. In the US Midwest, 100-year trends exhibit a transition towards more favorable conditions, with cooler summer temperature extremes and increased precipitation. Statistically significant correspondence is found between the cooling pattern and trends in cropland intensification, as well as with trends towards greater irrigated land over a small subset of the domain. Land conversion to cropland, often considered an important influence on historical temperatures, is not significantly associated with cooling. We suggest that cooling is primarily associated with agricultural intensification increasing the potential for evapotranspiration, consistent with our finding that cooling trends are greatest for the highest temperature percentiles, and that increased evapotranspiration generally leads to greater precipitation. Temperatures over rainfed croplands show no cooling trend during drought conditions, consistent with evapotranspiration requiring adequate soil moisture, and implying that modern drought events feature greater warming as baseline cooler temperatures revert to historically high extremes. Preliminary results indicate these relationships between temperature extremes, irrigation, and intensification are also observed in other major summer cropping systems, including northeast China, Argentina, and the Canadian Prairies.

  4. Grassland agriculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agriculture in grassland environments is facing multiple stresses from: shifting demographics, declining and fragmented agricultural landscapes, declining environmental quality, variable and changing climate, volatile and increasing energy costs, marginal economic returns, and globalization. Degrad...

  5. An Updated Decision Support Interface: A Tool for Remote Monitoring of Crop Growing Conditions

    NASA Astrophysics Data System (ADS)

    Husak, G. J.; Budde, M. E.; Rowland, J.; Verdin, J. P.; Funk, C. C.; Landsfeld, M. F.

    2014-12-01

    Remote sensing of agroclimatological variables to monitor food production conditions is a critical component of the Famine Early Warning Systems Network portfolio of tools for assessing food security in the developing world. The Decision Support Interface (DSI) seeks to integrate a number of remotely sensed and modeled variables to create a single, simplified portal for analysis of crop growing conditions. The DSI has been reformulated to incorporate more variables and give the user more freedom in exploring the available data. This refinement seeks to transition the DSI from a "first glance" agroclimatic indicator to one better suited for the differentiation of drought events. The DSI performs analysis of variables over primary agricultural zones at the first sub-national administrative level. It uses the spatially averaged rainfall, normalized difference vegetation index (NDVI), water requirement satisfaction index (WRSI), and actual evapotranspiration (ETa) to identify potential hazards to food security. Presenting this information in a web-based client gives food security analysts and decision makers a lightweight portal for information on crop growing conditions in the region. The crop zones used for the aggregation contain timing information which is critical to the DSI presentation. Rainfall and ETa are accumulated from different points in the crop phenology to identify season-long deficits in rainfall or transpiration that adversely affect the crop-growing conditions. Furthermore, the NDVI and WRSI serve as their own seasonal accumulated measures of growing conditions by capturing vegetation vigor or actual evapotranspiration deficits. The DSI is currently active for major growing regions of sub-Saharan Africa, with intention of expanding to other areas over the coming years.

  6. Agricultural Production.

    ERIC Educational Resources Information Center

    Lehigh County Area Vocational-Technical School, Schnecksville, PA.

    This brochure describes the philosophy and scope of a secondary-level course in agricultural production. Addressed in the individual units of the course are the following topics: careers in agriculture and agribusiness, animal science and livestock production, agronomy, agricultural mechanics, supervised occupational experience programs, and the…

  7. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems.

    PubMed

    Ladoni, Moslem; Kravchenko, Alexandra N; Robertson, G Phillip

    2015-01-01

    Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover) and non-leguminous (winter rye) cover crops on potentially mineralizable N (PMN) and [Formula: see text] levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4-5 times during each growing season and analyzed for [Formula: see text] and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3-N. Red clover cover crop increased [Formula: see text] by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on [Formula: see text] in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management in row

  8. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems

    PubMed Central

    Ladoni, Moslem; Kravchenko, Alexandra N.; Robertson, G. Phillip

    2015-01-01

    Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover) and non-leguminous (winter rye) cover crops on potentially mineralizable N (PMN) and NO3--N levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4–5 times during each growing season and analyzed for NO3--N and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3—N. Red clover cover crop increased NO3--N by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on NO3--N in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management in row-crop agricultural systems. PMID:26600462

  9. Rapidly changing climatic conditions for wine grape growing in the Okanagan Valley region of British Columbia, Canada.

    PubMed

    Rayne, Sierra; Forest, Kaya

    2016-06-15

    A statistical analysis was conducted on long-term climate records for sites bordering Okanagan Lake in the Okanagan Valley viticultural region of British Columbia, Canada. Average wine grape growing season temperatures are increasing rapidly in the area over the post-1980 period at rates upwards of 7.0±1.3°C/century. Similar increases in the average dormant season temperature are evident. These temperature changes are likely some of the most extreme observed among the world's wine producing areas during the past few decades. Growing degree day base 10°C (GDD10) has increased by nearly 50% at some locations since the 1970s, resulting in major impacts on the corresponding climate classification for viticulture. If current climate trends continue, the southern and central portions of the region will likely enter Winkler region II within the next few decades, placing them in the same category as well-established warmer wine regions from France, Spain, Italy, and Australia. The large dormant season temperature increases over the last several decades have resulted in the area no longer being a cold season outlier when compared to most other cool-climate viticultural areas. Based on average growing season temperatures, the southern end of Okanagan Lake has moved out of the cool-climate viticultural classification and into the intermediate zone, while the central and northern regions are now at the cool/intermediate viticulture interface, similar to the historical positions of the Rhine Valley in Germany, northern Oregon in the United States, and the Loire Valley, Burgundy-Cote, Burgundy-Beaujolais, and Champagne appelations of France. The corresponding suitable grape species for the area have evolved into warmer region varietals during this time frame, having substantial economic impacts on producers. Increased temperatures are also expected to bring greater threats from agricultural pests, notably Pierce's disease from the bacterium Xylella fastidiosa. PMID:26971218

  10. How Your Baby Grows

    MedlinePlus

    ... brain, the heart and lungs, are forming. The placenta grows in your uterus and supplies the baby ... like alcohol, cigarette smoke and drugs through the placenta, too. So don’t drink alcohol , smoke , use ...

  11. Apparatus for growing crystals

    NASA Technical Reports Server (NTRS)

    Jasinski, Thomas J. (Inventor); Witt, August F. (Inventor)

    1986-01-01

    An improved apparatus and method for growing crystals from a melt employing a heat pipe, consisting of one or more sections, each section serving to control temperature and thermal gradients in the crystal as it forms inside the pipe.

  12. A HELPING HAND, SEASONAL FARM LABOR IN NEW YORK STATE.

    ERIC Educational Resources Information Center

    DALRYMPLE, DANIEL M.; AND OTHERS

    NEW YORK STATE'S PROGRAM OF AID FOR ITS INTERSTATE AGRICULTURAL WORKERS IS PRESENTED. NEW YORK IS ONE OF THE MAJOR AGRICULTURAL STATES. THOUSANDS OF SEASONAL WORKERS ARE REQUIRED TO SUPPLEMENT INDIVIDUAL FARMERS, THEIR FAMILIES, AND REGULAR EMPLOYEES OF FRUIT AND VEGETABLE PROCESSING PLANTS. THE SEASONAL WORKER IS A KEY FIGURE IN THE STATE'S…

  13. Warming of the Indian Ocean Threatens Eastern and Southern Africa, but could be Mitigated by Agricultural Development

    NASA Technical Reports Server (NTRS)

    Funk, Chris; Dettinger, Michael D.; Brown, Molly E.; Michaelsen, Joel C.; Verdin, James P.; Barlow, Mathew; Howell, Andrew

    2008-01-01

    Since 1980, the number of undernourished people in eastern and southern Africa has more than doubled. Rural development stalled and rural poverty expanded during the 1990s. Population growth remains very high and declining per capita agricultural capacity retards progress towards Millennium Development goals. Analyses of in situ station data and satellite observations of precipitation identify another problematic trend. Main growing season rainfall receipts have diminished by approximately 15% in food insecure countries clustered along the western rim of the Indian Ocean. Occurring during the main growing seasons in poor countries dependent on rain fed agriculture, these declines are societally dangerous. Will they persist or intensify? Tracing moisture deficits upstream to an anthropogenically warming Indian Ocean leads us to conclude that further rainfall declines are likely. We present analyses suggesting that warming in the central Indian Ocean disrupts onshore moisture transports, reducing continental rainfall. Thus late 20th century anthropogenic Indian Ocean warming has probably already produced societally dangerous climate change by creating drought and social disruption in some of the world's most fragile food economies. We quantify the potential impacts of the observed precipitation and agricultural capacity trends by modeling millions of undernourished people as a function of rainfall, population, cultivated area, seed and fertilizer use. Persistence of current tendencies may result in a 50% increase in undernourished people. On the other hand, modest increases in per capita agricultural productivity could more than offset the observed precipitation declines. Investing in agricultural development can help mitigate climate change while decreasing rural poverty and vulnerability.

  14. Agricultural Waste.

    PubMed

    Xue, Ling; Zhang, Panpan; Shu, Huajie; Chang, Chein-Chi; Wang, Renqing; Zhang, Shuping

    2016-10-01

    In recent years, the quantity of agricultural waste has been rising rapidly all over the world. As a result, the environmental problems and negative impacts of agricultural waste are drawn more and more attention. Therefore, there is a need to adopt proper approaches to reduce and reuse agricultural waste. This review presented about 200 literatures published in 2015 relating to the topic of agricultural waste. The review examined research on agricultural waste in 2015 from the following four aspects: the characterization, reuse, treatment, and management. Researchers highlighted the importance to reuse agricultural waste and investigated the potential to utilize it as biofertilizers, cultivation material, soil amendments, adsorbent, material, energy recycling, enzyme and catalyst etc. The treatment of agricultural waste included carbonization, biodegradation, composting hydrolysis and pyrolysis. Moreover, this review analyzed the differences of the research progress in 2015 from 2014. It may help to reveal the new findings and new trends in this field in 2015 comparing to 2014. PMID:27620093

  15. Vocational Agriculture Education. Agricultural Mechanics.

    ERIC Educational Resources Information Center

    Smith, Eddie; And Others

    To assist teachers in agricultural mechanics in providing comprehensive instruction to their students, this curriculum guide treats both the mechanical skills and knowlege necessary for this specialized area. Six sections are included, as follow: orientation and safety; agricultural mechanics skills; agricultural power and machinery; agricultural…

  16. Capturing Weather-related Shocks In Smallholder Agriculture

    NASA Astrophysics Data System (ADS)

    Murray, S.

    2015-12-01

    Rainfed agriculture accounts for 93% of total cultivated area in SSA (FAO, 2002) and smallholder is the predominant form of farm organization (33 million with less than 2 ha, representing 80% of all farms). At the same time, 75% of extreme poor live in rural areas and 90% rely on agriculture. A poor harvest can have significant impact on livelihood and welfare of a household with limited coping mechanisms and little savings.This study aims to shed light on how small farmers are affected by growing conditions in a given season and how well these impacts can be predicted using objective measures derived from time-series of remote-sensing data. We investigate the covariate vs idiosyncratic nature of shocks experienced at the household level, using both community-level and household-level observations. We also test the relative efficiency of different metrics in predicting shocks, acknowledging that both spatial resolution and temporal frequency are likely to be limiting factors in the objective measures. To support this analysis we draw on surveys from the Living Standards Measurement Study Integrated Surveys on Agriculture (LSMS-ISA) project. The LSMS-ISA surveys are georeferenced, multi-topic panel surveys with a strong focus on agriculture, conducted in 7 African countries. We combine the LSMS-ISA data on production and agricultural shocks with objective measures (rainfall deficit/surplus, phenological variables, water requirements satisfaction index) derived from various data sources (CHIRPS, MODIS Land Cover Dynamics, NDVI3g). Objective measures will be considered in both absolute terms as well as deviation from mean in the survey season.

  17. An Interoperable, Agricultural Information System Based on Satellite Remote Sensing Data

    NASA Technical Reports Server (NTRS)

    Teng, William; Chiu, Long; Doraiswamy, Paul; Kempler, Steven; Liu, Zhong; Pham, Long; Rui, Hualan

    2005-01-01

    Monitoring global agricultural crop conditions during the growing season and estimating potential seasonal production are critically important for market development of US. agricultural products and for global food security. The Goddard Space Flight Center Earth Sciences Data and Information Services Center Distributed Active Archive Center (GES DISC DAAC) is developing an Agricultural Information System (AIS), evolved from an existing TRMM Online Visualization and Analysis System (TOVAS), which will operationally provide satellite remote sensing data products (e.g., rainfall) and services. The data products will include crop condition and yield prediction maps, generated from a crop growth model with satellite data inputs, in collaboration with the USDA Agricultural Research Service. The AIS will enable the remote, interoperable access to distributed data, by using the GrADS-DODS Server (GDS) and by being compliant with Open GIS Consortium standards. Users will be able to download individual files, perform interactive online analysis, as well as receive operational data flows. AIS outputs will be integrated into existing operational decision support systems for global crop monitoring, such as those of the USDA Foreign Agricultural Service and the U.N. World Food Program.

  18. Seasonal cultivated and fallow cropland mapping using MODIS-based automated cropland classification algorithm

    USGS Publications Warehouse

    Wu, Zhuoting; Thenkabail, Prasad S.; Mueller, Rick; Zakzeski, Audra; Melton, Forrest; Johnson, Lee; Rosevelt, Carolyn; Dwyer, John; Jones, Jeanine; Verdin, James P.

    2013-01-01

    Increasing drought occurrences and growing populations demand accurate, routine, and consistent cultivated and fallow cropland products to enable water and food security analysis. The overarching goal of this research was to develop and test automated cropland classification algorithm (ACCA) that provide accurate, consistent, and repeatable information on seasonal cultivated as well as seasonal fallow cropland extents and areas based on the Moderate Resolution Imaging Spectroradiometer remote sensing data. Seasonal ACCA development process involves writing series of iterative decision tree codes to separate cultivated and fallow croplands from noncroplands, aiming to accurately mirror reliable reference data sources. A pixel-by-pixel accuracy assessment when compared with the U.S. Department of Agriculture (USDA) cropland data showed, on average, a producer’s accuracy of 93% and a user’s accuracy of 85% across all months. Further, ACCA-derived cropland maps agreed well with the USDA Farm Service Agency crop acreage-reported data for both cultivated and fallow croplands with R-square values over 0.7 and field surveys with an accuracy of ≥95% for cultivated croplands and ≥76% for fallow croplands. Our results demonstrated the ability of ACCA to generate cropland products, such as cultivated and fallow cropland extents and areas, accurately, automatically, and repeatedly throughout the growing season.

  19. Agriculture, summary

    NASA Technical Reports Server (NTRS)

    Baldwin, R.

    1975-01-01

    Applications of remotely sensed data in agriculture are enumerated. These include: predictions of forage for range animal consumption, forest management, soil mapping, and crop inventory and management.

  20. Evaluation of the kriging method to predict 7-h seasonal mean ozone concentrations for estimating crop losses

    SciTech Connect

    Lefohn, A.S.; Knudsen, H.P.; Logan, J.A.; Simpson, J.; Bhumralkar, C.

    1987-05-01

    Using kriging, a statistical technique, the National Crop Loss Assessment Network (NCLAN) program estimated growing season 5-month (May-September) ambient 7-h mean O3 concentrations for each of the major crop growing areas of the US for 1978-1982. The O3 estimates were used to predict economic benefits anticipated by lowering O3 levels in the US. This paper reviews NCLAN's use of kriging to estimate 7-h seasonal mean O3 concentrations for crop growing regions. Although the original kriging program used by NCLAN incorrectly calculated the diagonal elements of the kriging equations, this omission did not result in significant errors in the predicted estimates. Most of the data used in estimating the 7-h seasonal values were obtained from urban areas; the use of these data tended to underestimate the 7-h seasonal O3 concentrations in rural areas. It is recommended that only O3 data that are representative of agricultural areas and have been collected under accepted quality assurance programs be used in future kriging efforts.

  1. Evaluation of the kriging method to predict 7-h seasonal mean ozone concentrations for estimating crop losses (journal version)

    SciTech Connect

    Lefohn, A.S.; Knudsen, H.P.; Logan, J.A.; Simpson, J.; Bhumralkar, C.

    1987-01-01

    Using kriging, a statistical technique, the National Crop Loss Assessment Network (NCLAN) program estimated growing season 5-month (May-September) ambient 7-h mean O/sub 3/ concentrations for each of the major crop growing areas of the United States for 1978-1982. The O/sub 3/ estimates were used to predict economic benefits anticipated by lowering O/sub 3/ levels in the United States. This paper reviews NCLAN's use of kriging to estimate 7-h seasonal mean O/sub 3/ concentrations for crop growing regions. Although the original kriging program used by NCLAN incorrectly calculated the diagonal elements of the kriging equations, this omission did not result in significant errors in the predicted estimates. Most of the data used in estimating the 7-h seasonal values were obtained from urban areas; the use of these data tended to underestimate the 7-h seasonal O/sub 3/ concentrations in rural areas. It is recommended that only O/sub 3/ data that are representative of agricultural areas and have been collected under accepted quality-assurance programs be used in future kriging efforts.

  2. Biophysical impacts of climate-smart agriculture in the Midwest United States.

    PubMed

    Bagley, Justin E; Miller, Jesse; Bernacchi, Carl J

    2015-09-01

    The potential impacts of climate change in the Midwest United States present unprecedented challenges to regional agriculture. In response to these challenges, a variety of climate-smart agricultural methodologies have been proposed to retain or improve crop yields, reduce agricultural greenhouse gas emissions, retain soil quality and increase climate resilience of agricultural systems. One component that is commonly neglected when assessing the environmental impacts of climate-smart agriculture is the biophysical impacts, where changes in ecosystem fluxes and storage of moisture and energy lead to perturbations in local climate and water availability. Using a combination of observational data and an agroecosystem model, a series of climate-smart agricultural scenarios were assessed to determine the biophysical impacts these techniques have in the Midwest United States. The first scenario extended the growing season for existing crops using future temperature and CO2 concentrations. The second scenario examined the biophysical impacts of no-till agriculture and the impacts of annually retaining crop debris. Finally, the third scenario evaluated the potential impacts that the adoption of perennial cultivars had on biophysical quantities. Each of these scenarios was found to have significant biophysical impacts. However, the timing and magnitude of the biophysical impacts differed between scenarios. PMID:25393245

  3. Managing the Sneezing Season

    MedlinePlus

    ... Javascript on. Feature: Managing Allergies Managing the Sneezing Season Past Issues / Summer 2011 Table of Contents Seasonal ... Read More "Managing Allergies" Articles Managing the Sneezing Season / A Pollen Primer / Seasonal Allergies: Symptoms, Diagnosis, and ...

  4. Growing Up with "1984."

    ERIC Educational Resources Information Center

    Franza, August

    1983-01-01

    Relates changing student reaction to George Orwell's "1984" over 20 years of teaching. Finds present high school students' acceptance of Orwell's bleak world vision both a sign of student honesty and a frightening indication of the growing reality of the book. (MM)

  5. Growing through Literature.

    ERIC Educational Resources Information Center

    Thomas, Barbara J.

    "Growing through Literature" is a curriculum using Joan M. and Erik H. Erikson's theory of the Life Cycle as a structure for selecting and teaching literature to inner-city high school students at Brighton High School in Massachusetts. The program consists of four component parts: Journals, Selected Stories, Discussion, and Autobiography. By…

  6. GROWING SEEDS, TEACHER'S GUIDE.

    ERIC Educational Resources Information Center

    Elementary Science Study, Newton, MA.

    THIS TEACHER'S GUIDE IS DESIGNED FOR USE WITH AN ELEMENTARY SCIENCE STUDY UNIT, "GROWING SEEDS," IN WHICH SUCH BASIC SCIENCE SKILLS AND PROCESSES AS MEASUREMENT, OBSERVATION, AND HYPOTHESIS FORMATION ARE INTRODUCED THROUGH STUDENT ACTIVITIES INVOLVING SEEDS, GERMINATION, AND SEEDLING GROWTH. THE MATERIALS WERE DEVELOPED FOR USE IN ELEMENTARY…

  7. Growing Up In Appalachia.

    ERIC Educational Resources Information Center

    Reed, Judith

    1981-01-01

    Offers a glimpse of a Smithsonian Institution Traveling Exhibition of 80 photographs and selected writings by first through eighth grade children growing up in Letcher County, Kentucky. Children were guided by an artist-in-residence sponsored by the Kentucky Arts Commission and Appalshop, a multimedia cooperative. (Author/RH)

  8. Growing Backyard Textiles

    ERIC Educational Resources Information Center

    Nelson, Eleanor Hall

    1975-01-01

    For those involved in creative work with textiles, the degree of control possible in texture, finish, and color of fiber by growing and processing one's own (perhaps with students' help) can make the experience rewarding. The author describes the processes for flax and nettles and gives tips on necessary equipment. (Author/AJ)

  9. Growing Plants in School.

    ERIC Educational Resources Information Center

    Salt, Bernard

    1990-01-01

    Background information on the methods and varieties used to demonstrate the cultivation of plants without the use of chemical pesticides is provided. Discussed are species and variety selection, growing plants from seed and from seedlings, soil preparation, using cuttings, useful crops, and pest control. (CW)

  10. Growing a Nurturing Classroom

    ERIC Educational Resources Information Center

    Boorn, Clare; Dunn, Paula Hopkins; Page, Claire

    2010-01-01

    "Growing a nurturing classroom" is an awareness training programme presented by educational psychologists in Leicestershire for professionals working in primary schools with the aim of promoting an optimal environment for learning and emotional well-being. The training helps primary school staff to take a holistic approach to education; see…

  11. Agriculture intensifies soil moisture decline in Northern China.

    PubMed

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego G; Teuling, Adriaan J; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-01-01

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983-2012, we find that topsoil (0-50 cm) volumetric water content during the growing season has declined significantly (p < 0.01), with a trend of -0.011 to -0.015 m(3) m(-3) per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system. PMID:26158774

  12. Agriculture intensifies soil moisture decline in Northern China

    NASA Astrophysics Data System (ADS)

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego G.; Teuling, Adriaan J.; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-07-01

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983-2012, we find that topsoil (0-50 cm) volumetric water content during the growing season has declined significantly (p < 0.01), with a trend of -0.011 to -0.015 m3 m-3 per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system.

  13. Agriculture intensifies soil moisture decline in Northern China

    SciTech Connect

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego; Teuling, Adriann; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-07-09

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983–2012, we find that topsoil (0–50 cm) volumetric water content during the growing season has declined significantly (p<0.01), with a trend of -0.011 to -0.015 m3 m-3 per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system.

  14. Agriculture intensifies soil moisture decline in Northern China

    DOE PAGESBeta

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego; Teuling, Adriann; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; et al

    2015-07-09

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983–2012, we find that topsoil (0–50 cm) volumetric water content during the growing season has declined significantly (p<0.01), with a trend of -0.011 to -0.015 m3 m-3 per decade. Observed discharge declines for the three large river basins are consistentmore » with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system.« less

  15. Agriculture intensifies soil moisture decline in Northern China

    PubMed Central

    Liu, Yaling; Pan, Zhihua; Zhuang, Qianlai; Miralles, Diego G.; Teuling, Adriaan J.; Zhang, Tonglin; An, Pingli; Dong, Zhiqiang; Zhang, Jingting; He, Di; Wang, Liwei; Pan, Xuebiao; Bai, Wei; Niyogi, Dev

    2015-01-01

    Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983–2012, we find that topsoil (0–50 cm) volumetric water content during the growing season has declined significantly (p < 0.01), with a trend of −0.011 to −0.015 m3 m−3 per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favoured biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g., maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system. PMID:26158774

  16. MIGRATORY LABOR IN WISCONSIN AGRICULTURE.

    ERIC Educational Resources Information Center

    ROSE, A. THOMAS

    A SERIES OF CHARTS RELATED TO MIGRATORY WORKERS IN WISCONSIN IS PRESENTED. THE TABLES DEPICT THE SEASONAL AGRICULTURAL AND FOOD PROCESSING EMPLOYMENT TIMETABLE OF MAJOR CROP ACTIVITIES, UTILIZATION OF MIGRANT WORKERS IN SUCH ACTIVITIES, MIGRANT WORKERS REGISTERED BY DISTRICT OFFICES, STATE OF RESIDENCE, STATE OF LAST EMPLOYMENT, AND STATE OF NEXT…

  17. Partitioning of Evapotranspiration Using a Stable Water Isotope Technique in a High Temperature Agricultural Production System

    NASA Astrophysics Data System (ADS)

    Lu, X.; Liang, L.; Wang, L.; Jenerette, D.; Grantz, D. A.

    2015-12-01

    Agricultural production in the hot and arid low desert systems of southern California relies heavily on irrigation. A better understanding of how much and to what extent the irrigation water is transpired by crops relative to being lost through evaporation will contribute to better management of increasingly limited agricultural water resources. In this study, we examined the evapotranspiration (ET) partitioning over a field of forage sorghum (S. bicolor) during a growing season with several irrigation cycles. In several field campaigns we used continuous measurements of near-surface variations in the stable isotopic composition of water vapor (δ2H). We employed custom built transparent chambers coupled with a laser-based isotope analyzer and used Keeling plot and mass balance methods for surface flux partitioning. The preliminary results show that δT is more enriched than δE in the early growing season, and becomes less enriched than δE later in the season as canopy cover increases. There is an increase in the contribution of transpiration to ET as (1) leaf area index increases, and (2) as soil surface moisture declines. These results are consistent with theory, and extend these measurements to an environment that experiences extreme soil surface temperatures. The data further support the use of chamber based methods with stable isotopic analysis for characterization of ET partitioning in challenging field environments.

  18. Agricultural Wastes.

    ERIC Educational Resources Information Center

    Jewell, W. J.; Switzenbaum, M. S.

    1978-01-01

    Presents a literature review of agricultural wastes, covering publications of 1976-77. Some of the areas covered are: (1) water characteristics and impacts; (2) waste treatment; (3) reuse of agricultural wastes; and (4) nonpoint pollution sources. A list of 150 references is also presented. (HM)

  19. VOCATIONAL AGRICULTURE.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento. Research Coordinating Unit.

    TO ASSIST THOSE WHO MAKE DECISIONS RELATING TO EDUCATIONAL PROGRAMS IN AGRICULTURE, RECENT RESEARCH IN VOCATIONAL AGRICULTURE IS SUMMARIZED. A 1963 STUDY TREATS THE RELATIONSHIP BETWEEN WORK EXPERIENCE AND STUDENT CHARACTERISTICS, PLANS, AND ASPIRATIONS. STUDIES ON POST-SECONDARY EDUCATION CONCERN GUIDELINES FOR TECHNICIAN PROGRAMS, JUSTIFICATION…

  20. Predicting the Impacts of Climate Change on Agricultural Yields and Water Resources in the Maumee River Watershed

    NASA Astrophysics Data System (ADS)

    Nagelkirk, R. L.; Kendall, A. D.; Basso, B.; Hyndman, D. W.

    2012-12-01

    Climate change will likely have considerable effects on agriculture in the Midwestern United States. Under current climate projections, end-of-century temperatures rise by approximately 4 C, while precipitation stays relatively unchanged despite a potential increase in heavy rainfall events. These trends have already been observed over the last century: rising temperatures have extended the growing season two days per decade and heavy rainfall events have become twice as common. In an effort to understand the likely effects of climate change on agriculture, maize and soybean yields in the Maumee River Watershed were simulated using the Systems Approach to Land Use Sustainability (SALUS) crop model. SALUS calculates daily crop growth in response to changing climate, soil, and management conditions. We test the hypotheses that 1) despite any positive effects of CO2 fertilization and allowing for higher yielding varieties, longer and warmer growing seasons will lead to excessive water- and heat-stress, lowering yields under current management practices, and 2) that double-cropping maize and soybeans successively in the same season to offset these losses may become feasible if sufficient late-season soil moisture is made available. Outputs of daily Leaf Area Index (LAI) and root mass from a range of SALUS models are then distributed spatially to drive regional hydrologic simulations using the Integrated Landscape Hydrology Model (ILHM). These coupled simulations demonstrate the response of streamflow and groundwater levels to different management strategies.

  1. Factors affecting leaching in agricultural areas and an assessment of agricultural chemicals in the ground water of Kansas

    USGS Publications Warehouse

    Perry, C.A.; Robbins, F.V.; Barnes, P.L.

    1988-01-01

    As assessment of hydrologic factors and agricultural practices that may affect the leaching of agricultural chemicals to groundwater was conducted to evaluate the extent and severity of chemical contamination of groundwater resources in Kansas. The climate of a particular area determines the length of the growing season and the availability of water, at the surface and in the ground, for the growth of plants. Climate, together with surficial geology, soil, and principal aquifers, determines the types of crops to be planted,types of tillage, conservation and irrigation practices, and affects the quantity and method of application of agricultural chemicals. Examination of groundwater nitrate-nitrogen data collected from 766 wells throughout Kansas during 1976-81 indicated that 13 of 14 geohydrologic regions had wells producing samples that exceeded the 10-mg/L drinking water standard determined by the U.S. Environmental Protection Agency. One or more herbicides were detected in water samples from 11 of 56 wells during 1985-86 located in areas susceptible to agricultural leaching. Atrazine was the most common herbicide that was detected; it was detected in water at 9 of 11 wells. Cyanazine was detected in water at three wells; metolachlor at two wells; and metribuzin, alachlor, simazine, and propazine were detected at one well each. (USGS)

  2. Macromolecular crystal growing system

    NASA Technical Reports Server (NTRS)

    Snyder, Robert S. (Inventor); Herren, Blair J. (Inventor); Carter, Daniel C. (Inventor); Yost, Vaughn H. (Inventor); Bugg, Charles E. (Inventor); Delucas, Lawrence J. (Inventor); Suddath, Fred L. (Inventor)

    1991-01-01

    A macromolecular crystal growing system especially designed for growing crystals in the low gravity of space as well as the gravity of earth includes at least one tray assembly, a carrier assembly which receives the tray, and a refrigeration-incubation module in which the carrier assembly is received. The tray assembly includes a plurality of sealed chambers with a plastic syringe and a plug means for the double tip of the syringe provided therein. Ganging mechanisms operate the syringes and plugs simultaneously in a precise and smooth operation. Preferably, the tray assemblies are mounted on ball bearing slides for smooth operation in inserting and removing the tray assemblies into the carrier assembly. The plugging mechanism also includes a loading control mechanism. A mechanism for leaving a syringe unplugged is also provided.

  3. How to grow tomatoes.

    PubMed

    Kimura, Seisuke; Sinha, Neelima

    2008-01-01

    INTRODUCTIONTomatoes can be easily grown in a field, in a greenhouse, or in a growth cabinet. They need acidic soil (pH 6.0-6.8), a lot of light, and water. The optimum temperature for growing tomato plants and fruit is 18°C-24°C. This protocol describes how to germinate tomato seeds, cultivate adult plants, and harvest seeds from fruit. PMID:21356721

  4. Growing up with Retinoblastoma

    ERIC Educational Resources Information Center

    Maley, Tom

    2005-01-01

    An account is given of growing up as a child blinded as a result of a cancer of the eye known as retinoblastoma. The role of his mother is brought out, variously as a source of objective knowledge, of one's personal worth, and of the worth of other people in one's community. The strengths and weaknesses of his first school in his home area and…

  5. Measurement of gas and aerosol agricultural emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies of air quality indicate that agricultural emissions may impact particulate mass concentrations through both primary and secondary processes. Agriculture impacts can include primary dust emission, on-facility combustion from vehicles or seasonal field burning, and gaseous emissions from waste...

  6. Educating Children of Colorado's Agricultural Laborers.

    ERIC Educational Resources Information Center

    Wallace, George N.

    1980-01-01

    The article discusses potential remedies for three major issues that prevent seasonal agricultural workers from maintaining the kind of working and living conditions which lead to cohesive cumulative social experience: undocumented workers; worsening living and working environments; and societal attitudes regarding agricultural labor and its…

  7. Dual scale trend analysis to evaluate climatic and anthropogenic effects on the vegetated land surface in agricultural Russia

    NASA Astrophysics Data System (ADS)

    de Beurs, Kirsten; Henebry, Geoffrey

    2010-05-01

    Russia's population is projected to shrink by a staggering 29% by 2050. Differential dynamics among rural populations are correlated with ethnicity and constitute a key driver in the spatial disintegration of rural Russia. Currently, Russia is slowly transitioning into a country with an internal "archipelago" of islands of productive agriculture around cities set within a matrix of much less productive and abandoned croplands. This heterogeneous spatial pattern is mainly driven by depopulation of the least favorable parts of the countryside, where "least favorable" is some function of lower fertility of land, higher remoteness from urban markets, or both. Our aim is to improve current understanding of the interactions of climate change and the spatio-temporal impacts of agricultural reform in European Russia. We present a dual scale trend analysis to characterize change in agricultural European Russia. We selected a global NASA MODIS product (MCD43C4 and MCD43A4) at a 0.05° (~5.6 km) and 500m spatial resolution and a 16-day temporal resolution from 2000 through 2008. We applied a refinement of the Seasonal Kendal trend method to Normalized Difference Vegetation Index (NDVI) image series at both scales. We only incorporated composites during the vegetative growing season which was delineated by start of season and end of season estimates based on analysis of Normalized Difference Infrared Index (NDII) data. Trend patterns revealed areas of increasing NDVI trend in Russia which was linked through the dual scale analysis with agricultural land cover change. The coarser scale analysis was relevant to atmospheric boundary layer processes, while the finer scale data revealed trends that were more relevant to human decision-making and regional economics. We evaluated the weather patterns and land surface phenologies for the areas with increasing NDVI over the past 9 years and compared the results with agricultural areas without change. This analysis improved our

  8. Retrospective Analog Year Analyses Using NASA Satellite Data to Improve USDA's World Agricultural Supply and Demand Estimates

    NASA Technical Reports Server (NTRS)

    Teng, William; Shannon, Harlan

    2011-01-01

    The USDA World Agricultural Outlook Board (WAOB) is responsible for monitoring weather and climate impacts on domestic and foreign crop development. One of WAOB's primary goals is to determine the net cumulative effect of weather and climate anomalies on final crop yields. To this end, a broad array of information is consulted, including maps, charts, and time series of recent weather, climate, and crop observations; numerical output from weather and crop models; and reports from the press, USDA attach s, and foreign governments. The resulting agricultural weather assessments are published in the Weekly Weather and Crop Bulletin, to keep farmers, policy makers, and commercial agricultural interests informed of weather and climate impacts on agriculture. Because both the amount and timing of precipitation significantly affect crop yields, WAOB often uses precipitation time series to identify growing seasons with similar weather patterns and help estimate crop yields for the current growing season, based on observed yields in analog years. Historically, these analog years are visually identified; however, the qualitative nature of this method sometimes precludes the definitive identification of the best analog year. Thus, one goal of this study is to derive a more rigorous, statistical approach for identifying analog years, based on a modified coefficient of determination, termed the analog index (AI). A second goal is to compare the performance of AI for time series derived from surface-based observations vs. satellite-based measurements (NASA TRMM and other data).

  9. Migrant labor in agriculture: an international comparison.

    PubMed

    Martin, P L

    1985-01-01

    The May 1984 Conference on Migrant Labor in Agriculture at the University of California-Davis discussed papers by 22 farm labor experts from 12 nations. Each industrial nation utilizes a different set of public and private policies to supply workers for labor-intensive agriculture, but none is entirely satisfactory. Labor-intensive agriculture is becoming more dependent on workers who are shut out of labor markets. Some countries have simply accepted foreign workers in agriculture, while others have adopted policies to integrate farm and nonfarm labor markets. Polices to reduce agriculture's reliance on workers-without-options include restructuring employment practices to employ fewer seasonal workers for longer periods, mechanizing production, and importing fruits and vegetables from nearby developing countries. This article explains the salient features of labor-intensive agriculture, the various polices for obtaining seasonal farmworkers, and options to reduce farming's dependence on migrant labor. PMID:12267273

  10. Precision agriculture suitability to improve the terroir management in vineyard

    NASA Astrophysics Data System (ADS)

    María Terrón López, Jose; Blanco gallego, Jorge; Jesús Moral García, Francisco; Mancha Ramírez, Luis Alberto; Uriarte Hernández, David; Rafael Marques da Silva, Jose

    2014-05-01

    Precision agriculture is a useful tool to assess plant growth and development in vineyards. Traditional technics of crop management may be not enough to keep a certain level of crop yield or quality in grapes. Vegetation indices and soil based measurements, such as apparent electrical conductivity (ECa), can estimate the variability of the terroir within a specific water treatment toward the control of grapevine canopy properties. The current study focused on establishing the variability, spatial and temporal, in the vegetative development of a traditional management vineyard through to technics related to the precision agriculture. The study was carry out in a vineyard in the southwest of Spain during 2012 and 2013 growing seasons with two irrigations treatments, with four plots of each one, by one hand vines irrigated at 100% of crop evapotranspiration (ETc) and by other hand a dry farmed wines. Variations of soil properties across the assay were measured in each year at flowering stage by means of ECa, up to 80 cm. of soil depth, using mobile electrical contact sensors. Normalized difference vegetation index (NDVI) was determined in a concept of proximal sensing. In fact, the measures were made by multispectral sensors mounted in a terrestrial vehicle, in vertical positioning, at different stages during the ripening in both growing seasons. All measured data were statistically transformed to a behavior modeling pattern using principal component analisys (PCA) and compared by ordinary least square (OLS). NDVI showed a well-established pattern of vegetative development in both growing season for all the treatments at any irrigation treatment, let us appreciate the differences among the vegetative development of each plot within a specific irrigation treatment derived from the high soil variation that the ECa measures reflected. In this way, the local terroir of each plot and irrigation treatment influenced the vegetative growth showing that soil variations had a

  11. Hydrological consequences of deforestation and forest degradation in the Amazon agricultural frontier

    NASA Astrophysics Data System (ADS)

    Coe, M. T.; Macedo, M.; Riskin, S.

    2012-12-01

    Increasing demand for agricultural commodities has driven high rates of deforestation in the Brazilian Amazon over the last two decades. The resulting changes in land cover and use fundamentally alter the energy and water balance at the land surface. This study presents results from a series of intensive field campaigns and satellite remote sensing analyses quantifying the hydrological consequences of recent land cover and land use changes (LCLUC) that have occurred on a large ranch in the Amazon's agricultural frontier in the state of Mato Grosso, Brazil. The results show that deforestation and conversion to crops significantly decrease evapotranspiration and increase sensible heat flux. These changes occur because the crops that have replaced native forests have significantly lower leaf area index, root biomass, and growing season length, resulting in an overall decrease in water demand. This reduction in water demand leads to significantly increased soil moisture down to greater than 10m depth and a significant increase in water yield and stream discharge from all cropped watersheds measured, when compared to intact forest watersheds. This suite of changes occurred in all seasons and the differences in the water cycle between forested and non-forested areas on the ranch were particularly pronounced in the dry season. The results show that the evaporative flux from the evergreen forests remains high during the dry season due to extraction of stored soil moisture but becomes very low in the fallow fields where there are no photosynthetically active plants to evapotranspire.

  12. Biosurfactants in agriculture.

    PubMed

    Sachdev, Dhara P; Cameotra, Swaranjit S

    2013-02-01

    Agricultural productivity to meet growing demands of human population is a matter of great concern for all countries. Use of green compounds to achieve the sustainable agriculture is the present necessity. This review highlights the enormous use of harsh surfactants in agricultural soil and agrochemical industries. Biosurfactants which are reported to be produced by bacteria, yeasts, and fungi can serve as green surfactants. Biosurfactants are considered to be less toxic and eco-friendly and thus several types of biosurfactants have the potential to be commercially produced for extensive applications in pharmaceutical, cosmetics, and food industries. The biosurfactants synthesized by environmental isolates also has promising role in the agricultural industry. Many rhizosphere and plant associated microbes produce biosurfactant; these biomolecules play vital role in motility, signaling, and biofilm formation, indicating that biosurfactant governs plant-microbe interaction. In agriculture, biosurfactants can be used for plant pathogen elimination and for increasing the bioavailability of nutrient for beneficial plant associated microbes. Biosurfactants can widely be applied for improving the agricultural soil quality by soil remediation. These biomolecules can replace the harsh surfactant presently being used in million dollar pesticide industries. Thus, exploring biosurfactants from environmental isolates for investigating their potential role in plant growth promotion and other related agricultural applications warrants details research. Conventional methods are followed for screening the microbial population for production of biosurfactant. However, molecular methods are fewer in reaching biosurfactants from diverse microbial population and there is need to explore novel biosurfactant from uncultured microbes in soil biosphere by using advanced methodologies like functional metagenomics. PMID:23280539

  13. A soil water based index as a suitable agricultural drought indicator

    NASA Astrophysics Data System (ADS)

    Martínez-Fernández, J.; González-Zamora, A.; Sánchez, N.; Gumuzzio, A.

    2015-03-01

    Currently, the availability of soil water databases is increasing worldwide. The presence of a growing number of long-term soil moisture networks around the world and the impressive progress of remote sensing in recent years has allowed the scientific community and, in the very next future, a diverse group of users to obtain precise and frequent soil water measurements. Therefore, it is reasonable to consider soil water observations as a potential approach for monitoring agricultural drought. In the present work, a new approach to define the soil water deficit index (SWDI) is analyzed to use a soil water series for drought monitoring. In addition, simple and accurate methods using a soil moisture series solely to obtain soil water parameters (field capacity and wilting point) needed for calculating the index are evaluated. The application of the SWDI in an agricultural area of Spain presented good results at both daily and weekly time scales when compared to two climatic water deficit indicators (average correlation coefficient, R, 0.6) and to agricultural production. The long-term minimum, the growing season minimum and the 5th percentile of the soil moisture series are good estimators (coefficient of determination, R2, 0.81) for the wilting point. The minimum of the maximum value of the growing season is the best estimator (R2, 0.91) for field capacity. The use of these types of tools for drought monitoring can aid the better management of agricultural lands and water resources, mainly under the current scenario of climate uncertainty.

  14. Agriculture Education. Subject Matters Volume 3, No. 2.

    ERIC Educational Resources Information Center

    Reese, Susan

    2001-01-01

    "Growing in New Directions" describes how education must adapt to agriculture's move from small family farms to business conglomerates. "Keeping Agriculture Alive in the Suburbs" addresses marketing agricultural education to suburban students. "The Advantages of Agriculture Education and FFA" [Future Farmers of America] looks at careers in…

  15. Agricultural Microbiology.

    ERIC Educational Resources Information Center

    Brill, Winston J.

    1981-01-01

    Elucidates strategies for applying microbiological techniques to traditional agricultural practices. Discusses the manipulation of microorganisms that live with plants and also the problems involved in the introduction of new genes into crop plants by recombinant DNA methods. (CS)

  16. Agricultural Geophysics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The four geophysical methods predominantly used for agricultural purposes are resistivity, electromagnetic induction, ground penetrating radar (GPR), and time domain reflectometry (TDR). Resistivity and electromagnetic induction methods are typically employed to map lateral variations of apparent so...

  17. Agricultural Waste.

    PubMed

    Shu, Huajie; Zhang, Panpan; Chang, Chein-Chi; Wang, Renqing; Zhang, Shuping

    2015-10-01

    The management and disposal of agricultural waste are drawn more and more attention because of the increasing yields and negative effects on the environment. However, proper treatments such as converting abundant biomass wastes into biogas through anaerobic digestion technology, can not only avoid the negative impacts, but also convert waste into available resources. This review summarizes the studies of nearly two hundred scholars from the following four aspects: the characterization, reuse, treatment, and management of agricultural waste. PMID:26420088

  18. [Contribution of Base Flow to Total Nitrogen Loading in Subtropical Agricultural Catchments].

    PubMed

    Ma, Qiu-mei; Li, Wei; Wang, Yi; Liu, Xin-liang; Li, Yong; Wu, Jin-shui

    2016-04-15

    With the fast development of economics and improvement of people's living standard, non-point source pollution of the agricultural catchments in subtropical China has become more and more severe, where water quality deterioration has become a main barrier for sustainable development and ecological restoration. The process of ecohydrology in catchment is greatly influenced by the process of base flow in channel. This study selected the Tuojia and Jianshan catchments located in Changsha County, Hunan Province, to quantify and compare the contribution of base flow to total nitrogen (TN) loading from January 2011 to December 2013, through field observation and model estimation. The results suggested that the Tuojia catchment with higher intensity of rice agriculture had the greater volume of base flow, higher average flow-weighted TN concentration in base flow, and greater monthly TN loading via base flow [15.2 mm · month⁻¹, 4.14 mg · L⁻¹ and 0.54 kg · (hm² · month)⁻¹, respectively] than those in the Jianshan catchment with lower intensity [11.4 mm · month⁻¹, 1.72 mg · L⁻¹ and 0.20 kg · (hm² · month)⁻¹, respectively]. The base flow contribution to TN loading showed an apparently seasonal pattern. During rice-growing seasons, the contributions of base flow to TN loading were 23.2% and 18.6% in the Tuojia and Jianshan catchments, respectively, lower than those in the fallow seasons (46.9% and 40.0% correspondingly. These results suggested that rice agriculture increased the contribution of base flow in the fallow season to TN loading. Therefore, to alleviate the suffering of non-point source pollution in the rice agriculture catchments, reasonable management measure of rice fields should be implemented to decrease contrihution of base flow to TN loading. PMID:27548958

  19. Growing Unculturable Bacteria

    PubMed Central

    2012-01-01

    The bacteria that can be grown in the laboratory are only a small fraction of the total diversity that exists in nature. At all levels of bacterial phylogeny, uncultured clades that do not grow on standard media are playing critical roles in cycling carbon, nitrogen, and other elements, synthesizing novel natural products, and impacting the surrounding organisms and environment. While molecular techniques, such as metagenomic sequencing, can provide some information independent of our ability to culture these organisms, it is essentially impossible to learn new gene and pathway functions from pure sequence data. A true understanding of the physiology of these bacteria and their roles in ecology, host health, and natural product production requires their cultivation in the laboratory. Recent advances in growing these species include coculture with other bacteria, recreating the environment in the laboratory, and combining these approaches with microcultivation technology to increase throughput and access rare species. These studies are unraveling the molecular mechanisms of unculturability and are identifying growth factors that promote the growth of previously unculturable organisms. This minireview summarizes the recent discoveries in this area and discusses the potential future of the field. PMID:22661685

  20. Nonlinear growing neutrino cosmology

    NASA Astrophysics Data System (ADS)

    Ayaita, Youness; Baldi, Marco; Führer, Florian; Puchwein, Ewald; Wetterich, Christof

    2016-03-01

    The energy scale of dark energy, ˜2 ×10-3 eV , is a long way off compared to all known fundamental scales—except for the neutrino masses. If dark energy is dynamical and couples to neutrinos, this is no longer a coincidence. The time at which dark energy starts to behave as an effective cosmological constant can be linked to the time at which the cosmic neutrinos become nonrelativistic. This naturally places the onset of the Universe's accelerated expansion in recent cosmic history, addressing the why-now problem of dark energy. We show that these mechanisms indeed work in the growing neutrino quintessence model—even if the fully nonlinear structure formation and backreaction are taken into account, which were previously suspected of spoiling the cosmological evolution. The attractive force between neutrinos arising from their coupling to dark energy grows as large as 106 times the gravitational strength. This induces very rapid dynamics of neutrino fluctuations which are nonlinear at redshift z ≈2 . Nevertheless, a nonlinear stabilization phenomenon ensures only mildly nonlinear oscillating neutrino overdensities with a large-scale gravitational potential substantially smaller than that of cold dark matter perturbations. Depending on model parameters, the signals of large-scale neutrino lumps may render the cosmic neutrino background observable.

  1. Farming the Desert: agriculture in the World War II-era Japanese-American relocation centers.

    PubMed

    Lillquist, Karl

    2010-01-01

    In 1942 over 110,000 Japanese Americans were evacuated from the West Coast to ten inland, barbed wire-enclosed relocation centers in the name of national security. Agriculture was a key component of the eight arid to semi-arid centers located in the western United States. Each center's agricultural program included produce for human consumption, feed crops, and livestock. Some centers also grew seed, ornamental, and war crops. Evacuees raised and consumed five types of livestock and sixty-one produce varieties, including many traditional foods. Seasonal surpluses were preserved, shipped to other centers, or sold on the open market. Short growing seasons, poor soils, initially undeveloped lands, pests, equipment shortages, and labor issues hampered operations. However, imprisoned evacuee farmers proved that diverse agricultural programs could succeed in the harsh settings primarily because of labor-intensive farming methods, ingenuity, and the large markets provided by the centers. These agricultural programs played major roles in feeding, providing meaningful employment, and preparing evacuees for life outside the centers, and readied lands for post-war "homesteaders." PMID:20419893

  2. Mexican Workers and U.S. Agriculture: The Revolving Door.

    ERIC Educational Resources Information Center

    Martin, Philip

    2002-01-01

    Discusses agriculture and farming factors affecting immigration and integration policies. Examines seasonality, wages, and guest workers; the Immigration Reform and Control Act; and the search for seasonal workers. Data suggest that first generation immigrants age out of seasonal farm work with few skills to enable them to climb any job ladder,…

  3. Operational seasonal forecasting of crop performance.

    PubMed

    Stone, Roger C; Meinke, Holger

    2005-11-29

    Integrated, interdisciplinary crop performance forecasting systems, linked with appropriate decision and discussion support tools, could substantially improve operational decision making in agricultural management. Recent developments in connecting numerical weather prediction models and general circulation models with quantitative crop growth models offer the potential for development of integrated systems that incorporate components of long-term climate change. However, operational seasonal forecasting systems have little or no value unless they are able to change key management decisions. Changed decision making through incorporation of seasonal forecasting ultimately has to demonstrate improved long-term performance of the cropping enterprise. Simulation analyses conducted on specific production scenarios are especially useful in improving decisions, particularly if this is done in conjunction with development of decision-support systems and associated facilitated discussion groups. Improved management of the overall crop production system requires an interdisciplinary approach, where climate scientists, agricultural scientists and extension specialists are intimately linked with crop production managers in the development of targeted seasonal forecast systems. The same principle applies in developing improved operational management systems for commodity trading organizations, milling companies and agricultural marketing organizations. Application of seasonal forecast systems across the whole value chain in agricultural production offers considerable benefits in improving overall operational management of agricultural production. PMID:16433097

  4. Operational seasonal forecasting of crop performance

    PubMed Central

    Stone, Roger C; Meinke, Holger

    2005-01-01

    Integrated, interdisciplinary crop performance forecasting systems, linked with appropriate decision and discussion support tools, could substantially improve operational decision making in agricultural management. Recent developments in connecting numerical weather prediction models and general circulation models with quantitative crop growth models offer the potential for development of integrated systems that incorporate components of long-term climate change. However, operational seasonal forecasting systems have little or no value unless they are able to change key management decisions. Changed decision making through incorporation of seasonal forecasting ultimately has to demonstrate improved long-term performance of the cropping enterprise. Simulation analyses conducted on specific production scenarios are especially useful in improving decisions, particularly if this is done in conjunction with development of decision-support systems and associated facilitated discussion groups. Improved management of the overall crop production system requires an interdisciplinary approach, where climate scientists, agricultural scientists and extension specialists are intimately linked with crop production managers in the development of targeted seasonal forecast systems. The same principle applies in developing improved operational management systems for commodity trading organizations, milling companies and agricultural marketing organizations. Application of seasonal forecast systems across the whole value chain in agricultural production offers considerable benefits in improving overall operational management of agricultural production. PMID:16433097

  5. Multidecadal changes in moisture condition during climatic growing period of crops in Northeast China

    NASA Astrophysics Data System (ADS)

    Zhao, Junfang; Guo, Jianping

    Investigating the spatiotemporal dynamics of agricultural water status during crop growth season can provide scientific evidences for more efficient use of water resources and sustainable development of agricultural production under climate change. In this study, the following were used to evaluate the multidecadal changes in moisture condition during climatic growth period of crops in Northeast China from 1961 to 2010: (1) the daily climate variables gathered from 101 meteorological stations in Northeast China for 1961-2010; (2) FAO (Food and Agriculture Organization) Penman-Monteith equation; (3) 80% guaranteed probability for agro-climatic indicators; and (4) the daily average temperature stably passing 0 °C, which is the threshold temperature of climatic growth period for crops. Reference crop evapotranspiration (ET0) and relative moisture index were further calculated. The results showed that Northeast China's climate in the main agricultural areas over the past 50 years was warmer and drier in general, with a growing range and intensity of drought. From 1961 to 2010, when the daily average temperature stably passed 0 °C, the average annual total precipitation (P) and ET0 with 80% guaranteed probability in Northeast China both emerged as decreasing trends with averages of 555.0 mm and 993.7 mm, respectively. However, the decline in P was greater than that of annual total ET0. As a result, the annual relative moisture indices sharply decreased with an average of -0.44, mostly fluctuating from -0.59 to -0.25. As far as spatial distributions were concerned, the inter-regional reductions in P and relative moisture index over the past 50 years were conspicuous, especially in some agricultural areas of central Heilongjiang Province, northeastern Jilin Province and northeastern Liaoning Province. On the contrary, ET0 obviously increased in some agricultural areas of central and northwestern Heilongjiang Province (eg. Qiqiha'er, Shuangyashan, Hegang, Suihua, etc

  6. Growing a market economy

    SciTech Connect

    Basu, N.; Pryor, R.J.

    1997-09-01

    This report presents a microsimulation model of a transition economy. Transition is defined as the process of moving from a state-enterprise economy to a market economy. The emphasis is on growing a market economy starting from basic microprinciples. The model described in this report extends and modifies the capabilities of Aspen, a new agent-based model that is being developed at Sandia National Laboratories on a massively parallel Paragon computer. Aspen is significantly different from traditional models of the economy. Aspen`s emphasis on disequilibrium growth paths, its analysis based on evolution and emergent behavior rather than on a mechanistic view of society, and its use of learning algorithms to simulate the behavior of some agents rather than an assumption of perfect rationality make this model well-suited for analyzing economic variables of interest from transition economies. Preliminary results from several runs of the model are included.

  7. Extended season for northern butterflies

    NASA Astrophysics Data System (ADS)

    Karlsson, Bengt

    2014-07-01

    Butterflies are like all insects in that they are temperature sensitive and a changing climate with higher temperatures might effect their phenology. Several studies have found support for earlier flight dates among the investigated species. A comparative study with data from a citizen science project, including 66 species of butterflies in Sweden, was undertaken, and the result confirms that most butterfly species now fly earlier during the season. This is especially evident for butterflies overwintering as adults or as pupae. However, the advancement in phenology is correlated with flight date, and some late season species show no advancement or have even postponed their flight dates and are now flying later in the season. The results also showed that latitude had a strong effect on the adult flight date, and most of the investigated species showed significantly later flights towards the north. Only some late flying species showed an opposite trend, flying earlier in the north. A majority of the investigated species in this study showed a general response to temperature and advanced their flight dates with warmer temperatures (on average they advanced their flight dates by 3.8 days/°C), although not all species showed this response. In essence, a climate with earlier springs and longer growing seasons seems not to change the appearance patterns in a one-way direction. We now see butterflies on the wings both earlier and later in the season and some consequences of these patterns are discussed. So far, studies have concentrated mostly on early season butterfly-plant interactions but also late season studies are needed for a better understanding of long-term population consequences.

  8. Extended season for northern butterflies.

    PubMed

    Karlsson, Bengt

    2014-07-01

    Butterflies are like all insects in that they are temperature sensitive and a changing climate with higher temperatures might effect their phenology. Several studies have found support for earlier flight dates among the investigated species. A comparative study with data from a citizen science project, including 66 species of butterflies in Sweden, was undertaken, and the result confirms that most butterfly species now fly earlier during the season. This is especially evident for butterflies overwintering as adults or as pupae. However, the advancement in phenology is correlated with flight date, and some late season species show no advancement or have even postponed their flight dates and are now flying later in the season. The results also showed that latitude had a strong effect on the adult flight date, and most of the investigated species showed significantly later flights towards the north. Only some late flying species showed an opposite trend, flying earlier in the north. A majority of the investigated species in this study showed a general response to temperature and advanced their flight dates with warmer temperatures (on average they advanced their flight dates by 3.8 days/°C), although not all species showed this response. In essence, a climate with earlier springs and longer growing seasons seems not to change the appearance patterns in a one-way direction. We now see butterflies on the wings both earlier and later in the season and some consequences of these patterns are discussed. So far, studies have concentrated mostly on early season butterfly-plant interactions but also late season studies are needed for a better understanding of long-term population consequences. PMID:23456374

  9. Extended season for northern butterflies

    NASA Astrophysics Data System (ADS)

    Karlsson, Bengt

    2013-03-01

    Butterflies are like all insects in that they are temperature sensitive and a changing climate with higher temperatures might effect their phenology. Several studies have found support for earlier flight dates among the investigated species. A comparative study with data from a citizen science project, including 66 species of butterflies in Sweden, was undertaken, and the result confirms that most butterfly species now fly earlier during the season. This is especially evident for butterflies overwintering as adults or as pupae. However, the advancement in phenology is correlated with flight date, and some late season species show no advancement or have even postponed their flight dates and are now flying later in the season. The results also showed that latitude had a strong effect on the adult flight date, and most of the investigated species showed significantly later flights towards the north. Only some late flying species showed an opposite trend, flying earlier in the north. A majority of the investigated species in this study showed a general response to temperature and advanced their flight dates with warmer temperatures (on average they advanced their flight dates by 3.8 days/°C), although not all species showed this response. In essence, a climate with earlier springs and longer growing seasons seems not to change the appearance patterns in a one-way direction. We now see butterflies on the wings both earlier and later in the season and some consequences of these patterns are discussed. So far, studies have concentrated mostly on early season butterfly-plant interactions but also late season studies are needed for a better understanding of long-term population consequences.

  10. Introduction The Role of the Agricultural Model Intercomparison and Improvement Project

    NASA Technical Reports Server (NTRS)

    Rosenzweig, Cynthia; Hillel, Daniel

    2015-01-01

    Climate impacts on agriculture are of increasing concern in both the scientific and policy communities because of the need to ensure food security for a growing population. A special challenge is posed by the changes in the frequency and intensity of heat-waves, droughts, and episodic rainstorms already underway in many parts of the world. Changes in production are directly linked to such variations in temperature and precipitation during the growing season, and often to offseason changes in weather affecting soil-water storage and availability to crops. This is not an isolated problem but one of both global and regional importance, because of impacts on the livelihoods of smallholder farmers as well as consequences for the world food trade system. This two-part set the Agricultural Model Intercomparison and Improvement Project (AgMIP): Integrated Crop and Economic Assessments is the first to be entirely devoted to AgMIP (www.agmip.org). AgMIP is a major international research program focused on climate change and agriculture. The goal of the two parts is to advance the field by providing detailed information on new simulation techniques and assessments being conducted by this program. It presents information about new methods of global and regional integrated assessment, results from agricultural regions, and adaptation strategies for maintaining food security under changing climate conditions.

  11. The impact of climate extremes on US agricultural production and the buffering impacts of irrigation

    NASA Astrophysics Data System (ADS)

    Troy, Tara J.; Kipgen, Chinpihoi; Pal, Indrani

    2014-05-01

    In recent years, droughts and floods have occurred over many of the major growing regions of the world, resulting in decreased agricultural production and increased global food prices. Many climate projections call for more frequent extreme events, which could have significant impacts on agricultural yields and water resources in irrigated agricultural regions. In order to better understand the potential impact of climate extremes and the spatial heterogeneity of those impacts, we examine the associations between climate and irrigated and rain fed crop yields, focusing on four main staple crops: wheat, rice, soy, and maize. Because the United States has high spatial resolution data for both yields and weather variables, the analysis focuses on the impact of multiple extremes over these four crops in the US using statistical methods that do not require any assumptions of functional relationships between yields and weather variables. Irrigated and rain fed agricultural yields are analyzed separately to understand the role irrigation plays either as a buffering against climate variability and extremes such as drought, heat waves, and extended dry spells or a mechanism that leads to varied relationships between extremes of climate and yield fluctuations. These results demonstrate that irrigation has varying effects depending on the region, growing season timing, crop type, and type of climate extreme. This work has important implications for future planning of the coupled water-food system and its vulnerabilities to climate.

  12. Remotely Sensed Estimates of Evapotranspiration in Agricultural Areas of Northwestern Nevada: Drought, Reliance, and Water Transfers

    NASA Astrophysics Data System (ADS)

    Bromley, Matthew

    The arid landscape of northwestern Nevada is punctuated by agricultural communities that rely on water primarily supplied by the diversion of surface waters and secondarily by groundwater resources. Annual precipitation in the form of winter snowfall largely determines the amount of surface water that is available for irrigation for the following agricultural growing season. During years of insufficient surface water supplies, particular basins can use groundwater in order to meet irrigation needs. The amount of water used to irrigate agricultural land is influenced by land use changes, such as fallowing, and water right transfers from irrigation to municipal use. To evaluate agricultural water consumption with respect to variations in weather, water supply, and land use changes, monthly estimates of evapotranspiration (ET) were derived from Landsat multispectral optical and thermal imagery over a eleven-year period (2001 to 2011) and compared to variations in weather, water supply, and land use across four hydrographic areas in northwestern Nevada. Monthly ET was estimated using a land surface energy balance model, Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC), using Landsat 5 and Landsat 7 imagery combined with local atmospheric water demand estimates. Estimates of net ET were created by subtracting monthly precipitation from METRIC-derived ET, and seasonal estimates were generated by combining monthly ET for April-October (the regional agricultural growing season). Results highlight that a range of geographic, climatic, hydrographic, and anthropogenic factors influence ET. Hydrographic areas such as Mason Valley have the ability to mitigate deficiencies in surface water supplies by pumping supplemental groundwater, thereby resulting in low annual variability in ET. Conversely, the community of Lovelock has access to limited upstream surface water storage and is restricted by groundwater that is saline and unsuitable for

  13. Water Depletion Threatens Agriculture

    NASA Astrophysics Data System (ADS)

    Brauman, K. A.; Richter, B. D.; Postel, S.; Floerke, M.; Malsy, M.

    2014-12-01

    Irrigated agriculture is the human activity that has by far the largest impact on water, constituting 85% of global water consumption and 67% of global water withdrawals. Much of this water use occurs in places where water depletion, the ratio of water consumption to water availability, exceeds 75% for at least one month of the year. Although only 17% of global watershed area experiences depletion at this level or more, nearly 30% of total cropland and 60% of irrigated cropland are found in these depleted watersheds. Staple crops are particularly at risk, with 75% of global irrigated wheat production and 65% of irrigated maize production found in watersheds that are at least seasonally depleted. Of importance to textile production, 75% of cotton production occurs in the same watersheds. For crop production in depleted watersheds, we find that one half to two-thirds of production occurs in watersheds that have not just seasonal but annual water shortages, suggesting that re-distributing water supply over the course of the year cannot be an effective solution to shortage. We explore the degree to which irrigated production in depleted watersheds reflects limitations in supply, a byproduct of the need for irrigation in perennially or seasonally dry landscapes, and identify heavy irrigation consumption that leads to watershed depletion in more humid climates. For watersheds that are not depleted, we evaluate the potential impact of an increase in irrigated production. Finally, we evaluate the benefits of irrigated agriculture in depleted and non-depleted watersheds, quantifying the fraction of irrigated production going to food production, animal feed, and biofuels.

  14. An Extensive Survey of Gaseous Emissions from Rice Paddy Agriculture

    NASA Astrophysics Data System (ADS)

    Redeker, K. R.; Meinardi, S.; Blake, D.; Sass, R.; Cicerone, R.

    2002-05-01

    Rice agriculture currently occupies nearly 1% of the available land surface area of the globe. Increased population over the next few decades will drive the need for further expansion of global agriculture. Understanding atmospheric chemistry and climate change requires us to study small changes in relatively poorly quantified gases. In order to fully describe the effects of changing land use it is imperative to understand the relative shift in emissions post and prior to agricultural use for all relevant compounds. During the 2000 growing season we sampled over a commercial rice field in Houston TX. Our study surveyed over 45 separate compounds (up to C7), covering alkanes, alkenes, aromatics, isoprene, DMS, halocarbons, CFCs, and alkyl nitrates. We compare and include results from previous studies to complement our emissions. We include emissions from control plots (unplanted with rice, but flooded) that allows us to determine whether emissions are rice-plant dependent or are inherent in the rice paddy environment itself. Biomass burning estimates are calculated for fields where residue burning is practiced.

  15. Attributing the Risk of Late Onset of the Rainy Season in Southern Africa to Climate Change

    NASA Astrophysics Data System (ADS)

    Wolski, P.; Stone, D. A.; Tadross, M. A.; Hewitson, B.; Wehner, M. F.

    2015-12-01

    Rainfed subsistence agriculture in Sub-Saharan Africa accounts for approximately 96% of all cropland. This, combined with strong intra-seasonal and interannual variability of rains makes food production sensitive to climate variations, and increases the potential and frequent occurrence of climate-triggered famines. Farmers often identify the timing of the onset of the growing season (in many areas dependent predominantly on rainfall) as a key climate characteristic which influences crop yields, influences planting activities, and can be used to adapt to changing seasonal conditions without requiring additional resources. It is thus important to understand factors affecting the timing of the onset of rains, particularly how anthropogenic climate change may increase the risk of later onsets. Here, we present a study designed to assess the level of influence of anthropogenic CO2 emissions on the risk of late onset in southern Africa. Considering numerous definitions of rainy season onset, we use one that describes onset related to the growing of maize, as it is the most wide-ranging and consumed staple in the region. Attribution is done using a risk-based event attribution methodology in which we use dedicated simulations by AGCMs (HadAM3p-N96 and CAM5.1-1degree) performed in the framework of the Climate of the 20th Century Plus (C20C+) Detection and Attribution Project. These simulations enable comparison of event (in our case the timing of the onset of a particular rainy season) probabilities under real world climates with those under a climate that might have been had human activities not emitted greenhouse gases. The fraction of risk of later onsets, attributable to an increase in greenhouse gases, is done in a spatially-explicit way for onset events derived from observed and reanalysis data for the 2007-2014 period.

  16. Growing vortex patches

    NASA Astrophysics Data System (ADS)

    Crowdy, Darren; Marshall, Jonathan

    2004-08-01

    This paper demonstrates that two well-known equilibrium solutions of the Euler equations—the corotating point vortex pair and the Rankine vortex—are connected by a continuous branch of exact solutions. The central idea is to "grow" new vortex patches at two stagnation points that exist in the frame of reference of the corotating point vortex pair. This is done by generalizing a mathematical technique for constructing vortex equilibria first presented by Crowdy [D. G. Crowdy, "A class of exact multipolar vortices," Phys. Fluids 11, 2556 (1999)]. The solutions exhibit several interesting features, including the merging of two separate vortex patches via the development of touching cusps. Numerical contour dynamics methods are used to verify the mathematical solutions and reveal them to be robust structures. The general issue of how simple vortex equilibria can be continued continuously to more complicated ones with very different vortical topologies is discussed. The solutions are examples of exact solutions of the Euler equations involving multiple interacting vortex patches.

  17. Growing for different ends.

    PubMed

    Catts, Oron; Zurr, Ionat

    2014-11-01

    Tissue engineering and regenerative biology are usually discussed in relation to biomedical research and applications. However, hand in hand with developments of this field in the biomedical context, other approaches and uses for non-medical ends have been explored. There is a growing interest in exploring spin off tissue engineering and regenerative biology technologies in areas such as consumer products, art and design. This paper outlines developments regarding in vitro meat and leather, actuators and bio-mechanic interfaces, speculative design and contemporary artistic practices. The authors draw on their extensive experience of using tissue engineering for non-medical ends to speculate about what lead to these applications and their possible future development and uses. Avoiding utopian and dystopian postures and using the notion of the contestable, this paper also mentions some philosophical and ethical consideration stemming from the use of non-medical approaches to tissue constructs. This article is part of a directed issue entitled: Regenerative Medicine: the challenge of translation. PMID:25286303

  18. COLT: seasonal prediction of crop irrigation needs

    NASA Astrophysics Data System (ADS)

    Villani, Giulia; Spisni, Andrea; Mariani, Maria Cristina; Pratizzoli, William; Pavan, Valentina; Tomei, Fausto; Botarelli, Lucio; Marletto, Vittorio

    2013-04-01

    COLT is an operational chain to predict summer (June, July, August) crop irrigation needs in Emilia-Romagna (Northern Italy) at the regional and lower scales. Set up by ARPA-SIMC in 2010, it has been applied since with good results. COLT predicts summer irrigation needs in May, i.e. at the beginning of the irrigation season in Emilia-Romagna. COLT is based on the production of yearly updated land use maps, observed daily weather data, a regional soil map and ensemble probabilistic seasonal weather forecasts obtained from the EUROSIP multi-model operational system and a geographical soil water balance model (CRITERIA). The first step of the operational scheme is the supervised classification of crops through field surveys and a set of multitemporal satellite images acquired during the first months of the growing period. As the identification of all crop species during the satellite working windows is not feasible, they are grouped in six classes: summer field crops (including corn, sorghum, tomato, sugar beet, potato and others), winter crops (wheat, barley, oat, etc.), perennial grasses (alfa-alfa and meadows), rice, vineyards and orchards, on the whole regional plain, covering about 775000 ha. The second step involves the statistical downscaling of the EUROSIP ensemble predictions over Emilia-Romagna and the use of a weather generator to synthetically produce a number (usually 50) replicated meteorological summer daily data series, consistent with the predicted and downscaled summer anomalies of temperature, rainfall and other related indices. During the final step the CRITERIA model computes crop development and soil water balance on the crop classification map using observed meteorological daily data up to the end of May. Afterword forecasts are used up to the end of the summer irrigation season, i.e. August 31st. The statistical distribution projections of summer irrigation needs at the regional and reclamation consortia scale are then issued and disseminated

  19. Agricultural Biodiversity.

    ERIC Educational Resources Information Center

    Postance, Jim

    1998-01-01

    The extinction of farm animals and crops is rarely brought up during discussions of endangered species and biodiversity; however, the loss of diversity in crops and livestock threatens the sustainability of agriculture. Presents three activities: (1) "The Colors of Diversity"; (2) "Biodiversity among Animals"; and (3) "Heirloom Plants." Discusses…

  20. AGRICULTURAL EXTENSION.

    ERIC Educational Resources Information Center

    FARQUHAR, R.N.

    AUSTRALIAN AGRICULTURAL EXTENSION HAS LONG EMPHASIZED TECHNICAL ADVISORY SERVICE AT THE EXPENSE OF THE SOCIOECONOMIC ASPECTS OF FARM PRODUCTION AND FARM LIFE. ONLY IN TASMANIA HAS FARM MANAGEMENT BEEN STRESSED. DEMANDS FOR THE WHOLE-FARM APPROACH HAVE PRODUCED A TREND TOWARD GENERALISM FOR DISTRICT OFFICERS IN MOST STATES. THE FEDERAL GOVERNMENT,…

  1. AGRICULTURAL EDUCATION.

    ERIC Educational Resources Information Center

    DEALTON, ERNEST L.

    TODAY'S SUCCESSFUL FARMER MUST POSSESS THE SKILLS OF A BUSINESSMAN, SCIENTIST, AND MECHANIC TO SURVIVE COMPETITION IN AGRICULTURE, THE LARGEST INDUSTRY IN THE UNITED STATES. THIS COMPETITION HAS CAUSED AN INCREASE IN THE SIZE OF FARMS AND RANCHES IN AN ATTEMPT TO CURTAIL OPERATIONAL EXPENSES AND TO INCREASE PRODUCTION. WITH THE SCIENTIFIC…

  2. Hot Spots and Hot Moments of Methylmercury Production Associated With Agricultural and Non-agricultural Wetlands of the Yolo Bypass Wildlife Area, California

    NASA Astrophysics Data System (ADS)

    Marvin-Dipasquale, M.; Windham-Myers, L.; Agee, J. L.; Kakouros, E.; Cox, M. H.; Fleck, J.; Alpers, C. N.; Stephenson, M.

    2008-12-01

    The Yolo Bypass Wildlife Area (YBWA) is part of the larger Yolo Bypass floodwater protection zone associated with the Sacramento River and the Sacramento-San Joaquin Delta, in California. While mercury contamination is widespread throughout the region due to historic mining practices, the Yolo Bypass is responsible for a high proportion of the aqueous methylmercury (MeHg) entering the Delta, and biota from the Yolo Bypass are particularly elevated in toxic MeHg. Land use in the YBWA includes seasonally flooded agricultural fields (white rice, wild rice, fallow fields), and permanently and seasonally flooded non-agricultural wetlands used for resident and migratory waterfowl. Mercury biogeochemistry was examined in 0-2 cm surface sediment, as a function of habitat type, wetland management, and agricultural practices during the 2007-08 crop year. In permanently flooded wetlands, MeHg concentrations varied within a narrow range (ca. 0.5-1.5 ng/g dry wt) throughout the study period. In contrast, the three types of agricultural fields had higher MeHg concentrations throughout the rice-growing season (June-Sept; ca. 1.5-3.5 ng/g), and exhibited the highest levels (ca. 3.3-6.3 ng/g) in the post-harvest winter period (Dec-Feb). Further, naturally dried sediment, sampled during July '08 from post-harvest drained fallow agricultural fields (prior to reflooding) had MeHg concentrations that were also quite elevated (3.1 +/- 1.5 ng/g). This suggests that the initial elevated concentrations of overlying water MeHg, sometimes measured soon after flooding previously dried fields, may be related to the release of MeHg formed during the previous wet season and trapped in dried sediment, as opposed to being MeHg newly produced by bacteria upon soil rewetting. These results indicate that the 'hot spots and hot moments' associated with MeHg production in this system are linked to hydrologic manipulations (wetting and drying) in the agricultural fields, and that the practice of post

  3. Investigate the Capabilities of Remotely Sensed Crop Indicators for Agricultural Drought Monitoring in Kansas

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Becker-Reshef, I.; Justice, C. O.

    2013-12-01

    Although agricultural production has been rising in the past years, drought remains the primary cause of crop failure, leading to food price instability and threatening food security. The recent 'Global Food Crisis' in 2008, 2011 and 2012 has put drought and its impact on crop production at the forefront, highlighting the need for effective agricultural drought monitoring. Satellite observations have proven a practical, cost-effective and dynamic tool for drought monitoring. However, most satellite based methods are not specially developed for agriculture and their performances for agricultural drought monitoring still need further development. Wheat is the most widely grown crop in the world, and the recent droughts highlight the importance of drought monitoring in major wheat producing areas. As the largest wheat producing state in the US, Kansas plays an important role in both global and domestic wheat markets. Thus, the objective of this study is to investigate the capabilities of remotely sensed crop indicators for effective agricultural drought monitoring in Kansas wheat-grown regions using MODIS data and crop yield statistics. First, crop indicators such as NDVI, anomaly and cumulative metrics were calculated. Second, the varying impacts of agricultural drought at different stages were explored by examining the relationship between the derived indicators and yields. Also, the starting date of effective agricultural drought early detection and the key agricultural drought alert period were identified. Finally, the thresholds of these indicators for agricultural drought early warning were derived and the implications of these indicators for agricultural drought monitoring were discussed. The preliminary results indicate that drought shows significant impacts from the mid-growing-season (after Mid-April); NDVI anomaly shows effective drought early detection from Late-April, and Late-April to Early-June can be used as the key alert period for agricultural

  4. Assessing levels and seasonal variations of current-use pesticides (CUPs) in the Tuscan atmosphere, Italy, using polyurethane foam disks (PUF) passive air samplers.

    PubMed

    Estellano, Victor H; Pozo, Karla; Efstathiou, Christos; Pozo, Katerine; Corsolini, Simonetta; Focardi, Silvano

    2015-10-01

    Polyurethane foam disks (PUF) passive air samplers (PAS) were deployed over 4 sampling periods of 3-5-months (≥ 1 year) at ten urban and rural locations throughout the Tuscany Region. The purpose was to assess the occurrence and seasonal variations of ten current-use pesticides (CUPs). PUF disk extracts were analyzed using GC-MS. The organophosphates insecticides; chlorpyrifos (3-580 pg m(-3)) and chlorpyrifos-methyl (below detection limit - to 570 pg m(-3)) presented the highest levels in air, and showed seasonal fluctuation coinciding with the growing seasons. The relative proportion urban/(urban + rural) ranged from 0.4 to 0.7 showing no differences between urban and rural concentrations. Air back trajectories analysis showed air masses passing over agricultural fields and potentially enhancing the drift of pesticides into the urban sites. This study represents the first information regarding CUPs in the atmosphere of Tuscany region using PAS-PUF disk. PMID:26005863

  5. 7 CFR 301.89-15 - Compensation for growers, handlers, and seed companies in the 1999-2000 and subsequent crop seasons.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... grower in the 2000-2001 growing season for use as seed in the next growing season, and wheat grown with... kernel, this requirement applies to compensation for wheat from the 2002-2003 and subsequent crop...

  6. 7 CFR 301.89-15 - Compensation for growers, handlers, and seed companies in the 1999-2000 and subsequent crop seasons.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... grower in the 2000-2001 growing season for use as seed in the next growing season, and wheat grown with... kernel, this requirement applies to compensation for wheat from the 2002-2003 and subsequent crop...

  7. How Do Galaxies Grow?

    NASA Astrophysics Data System (ADS)

    2008-08-01

    Astronomers have caught multiple massive galaxies in the act of merging about 4 billion years ago. This discovery, made possible by combining the power of the best ground- and space-based telescopes, uniquely supports the favoured theory of how galaxies form. ESO PR Photo 24/08 ESO PR Photo 24/08 Merging Galaxies in Groups How do galaxies form? The most widely accepted answer to this fundamental question is the model of 'hierarchical formation', a step-wise process in which small galaxies merge to build larger ones. One can think of the galaxies forming in a similar way to how streams merge to form rivers, and how these rivers, in turn, merge to form an even larger river. This theoretical model predicts that massive galaxies grow through many merging events in their lifetime. But when did their cosmological growth spurts finish? When did the most massive galaxies get most of their mass? To answer these questions, astronomers study massive galaxies in clusters, the cosmological equivalent of cities filled with galaxies. "Whether the brightest galaxies in clusters grew substantially in the last few billion years is intensely debated. Our observations show that in this time, these galaxies have increased their mass by 50%," says Kim-Vy Tran from the University of Zürich, Switzerland, who led the research. The astronomers made use of a large ensemble of telescopes and instruments, including ESO's Very Large Telescope (VLT) and the Hubble Space Telescope, to study in great detail galaxies located 4 billion light-years away. These galaxies lie in an extraordinary system made of four galaxy groups that will assemble into a cluster. In particular, the team took images with VIMOS and spectra with FORS2, both instruments on the VLT. From these and other observations, the astronomers could identify a total of 198 galaxies belonging to these four groups. The brightest galaxies in each group contain between 100 and 1000 billion of stars, a property that makes them comparable

  8. 7 CFR 3560.568 - Supplemental requirements for seasonal off-farm labor housing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Supplemental requirements for seasonal off-farm labor housing. 3560.568 Section 3560.568 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF AGRICULTURE DIRECT MULTI-FAMILY HOUSING LOANS AND GRANTS Off-Farm Labor Housing § 3560.568...

  9. 7 CFR Exhibit I to Subpart A of... - Guidelines for Seasonal Farm Labor Housing

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Guidelines for Seasonal Farm Labor Housing I Exhibit I to Subpart A of Part 1924 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE SERVICE, RURAL UTILITIES SERVICE, AND FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE...

  10. 7 CFR 3560.568 - Supplemental requirements for seasonal off-farm labor housing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Supplemental requirements for seasonal off-farm labor housing. 3560.568 Section 3560.568 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, DEPARTMENT OF AGRICULTURE DIRECT MULTI-FAMILY HOUSING LOANS AND GRANTS Off-Farm Labor Housing § 3560.568...

  11. Growing Galaxies Gently

    NASA Astrophysics Data System (ADS)

    2010-10-01

    New observations from ESO's Very Large Telescope have, for the first time, provided direct evidence that young galaxies can grow by sucking in the cool gas around them and using it as fuel for the formation of many new stars. In the first few billion years after the Big Bang the mass of a typical galaxy increased dramatically and understanding why this happened is one of the hottest problems in modern astrophysics. The results appear in the 14 October issue of the journal Nature. The first galaxies formed well before the Universe was one billion years old and were much smaller than the giant systems - including the Milky Way - that we see today. So somehow the average galaxy size has increased as the Universe has evolved. Galaxies often collide and then merge to form larger systems and this process is certainly an important growth mechanism. However, an additional, gentler way has been proposed. A European team of astronomers has used ESO's Very Large Telescope to test this very different idea - that young galaxies can also grow by sucking in cool streams of the hydrogen and helium gas that filled the early Universe and forming new stars from this primitive material. Just as a commercial company can expand either by merging with other companies, or by hiring more staff, young galaxies could perhaps also grow in two different ways - by merging with other galaxies or by accreting material. The team leader, Giovanni Cresci (Osservatorio Astrofisico di Arcetri) says: "The new results from the VLT are the first direct evidence that the accretion of pristine gas really happened and was enough to fuel vigorous star formation and the growth of massive galaxies in the young Universe." The discovery will have a major impact on our understanding of the evolution of the Universe from the Big Bang to the present day. Theories of galaxy formation and evolution may have to be re-written. The group began by selecting three very distant galaxies to see if they could find evidence

  12. Growing Galaxies Gently

    NASA Astrophysics Data System (ADS)

    2010-10-01

    New observations from ESO's Very Large Telescope have, for the first time, provided direct evidence that young galaxies can grow by sucking in the cool gas around them and using it as fuel for the formation of many new stars. In the first few billion years after the Big Bang the mass of a typical galaxy increased dramatically and understanding why this happened is one of the hottest problems in modern astrophysics. The results appear in the 14 October issue of the journal Nature. The first galaxies formed well before the Universe was one billion years old and were much smaller than the giant systems - including the Milky Way - that we see today. So somehow the average galaxy size has increased as the Universe has evolved. Galaxies often collide and then merge to form larger systems and this process is certainly an important growth mechanism. However, an additional, gentler way has been proposed. A European team of astronomers has used ESO's Very Large Telescope to test this very different idea - that young galaxies can also grow by sucking in cool streams of the hydrogen and helium gas that filled the early Universe and forming new stars from this primitive material. Just as a commercial company can expand either by merging with other companies, or by hiring more staff, young galaxies could perhaps also grow in two different ways - by merging with other galaxies or by accreting material. The team leader, Giovanni Cresci (Osservatorio Astrofisico di Arcetri) says: "The new results from the VLT are the first direct evidence that the accretion of pristine gas really happened and was enough to fuel vigorous star formation and the growth of massive galaxies in the young Universe." The discovery will have a major impact on our understanding of the evolution of the Universe from the Big Bang to the present day. Theories of galaxy formation and evolution may have to be re-written. The group began by selecting three very distant galaxies to see if they could find evidence

  13. Seasonal Life: Farmworkers, Children, and Socialization.

    ERIC Educational Resources Information Center

    Shimahara, Nobuo K.; Condon, Eliane

    This monograph is the result of an ethnographic study, conducted between 1981 and 1982, to explore the social conditions under which migrant and seasonal farm workers and their families lived and their children were socialized. The study was conducted in a large agricultural county in New Jersey. At the time of the study, the county had slightly…

  14. An agricultural survey for more than 9,500 African households.

    PubMed

    Waha, Katharina; Zipf, Birgit; Kurukulasuriya, Pradeep; Hassan, Rashid M

    2016-01-01

    Surveys for more than 9,500 households were conducted in the growing seasons 2002/2003 or 2003/2004 in eleven African countries: Burkina Faso, Cameroon, Ghana, Niger and Senegal in western Africa; Egypt in northern Africa; Ethiopia and Kenya in eastern Africa; South Africa, Zambia and Zimbabwe in southern Africa. Households were chosen randomly in districts that are representative for key agro-climatic zones and farming systems. The data set specifies farming systems characteristics that can help inform about the importance of each system for a country's agricultural production and its ability to cope with short- and long-term climate changes or extreme weather events. Further it informs about the location of smallholders and vulnerable systems and permits benchmarking agricultural systems characteristics. PMID:27218890

  15. Intensification through diversified resource use: the human ecology of a successful agricultural industry in Indonesian Borneo

    SciTech Connect

    Vondal, P.J.

    1987-03-01

    The success of an agricultural industry in commercial duck egg production in the swamplands of South Kalimantan (Borneo) is examined through the utilization of a human ecology framework. Seasonality of resource availability and human population growth are identified as two major constraints to production faced by farmers. Population increases in the urban sectors of southeastern Borneo also present economic opportunities for farmers because of the growing demand for poultry products. Farmers have responded by developing an intensification strategy in egg production based on the use of diversified resources for duck feed. The long-term consequences of these and other innovations in duck farming are discussed; and diversity-stability theory is examined for its applicability to this case of agricultural development and for rural development theory and practice.

  16. An agricultural survey for more than 9,500 African households

    PubMed Central

    Waha, Katharina; Zipf, Birgit; Kurukulasuriya, Pradeep; Hassan, Rashid M.

    2016-01-01

    Surveys for more than 9,500 households were conducted in the growing seasons 2002/2003 or 2003/2004 in eleven African countries: Burkina Faso, Cameroon, Ghana, Niger and Senegal in western Africa; Egypt in northern Africa; Ethiopia and Kenya in eastern Africa; South Africa, Zambia and Zimbabwe in southern Africa. Households were chosen randomly in districts that are representative for key agro-climatic zones and farming systems. The data set specifies farming systems characteristics that can help inform about the importance of each system for a country’s agricultural production and its ability to cope with short- and long-term climate changes or extreme weather events. Further it informs about the location of smallholders and vulnerable systems and permits benchmarking agricultural systems characteristics. PMID:27218890

  17. The Effect of El Niño on Agricultural Water Balances in Guatemala

    NASA Astrophysics Data System (ADS)

    Pedreros, D.; Michaelsen, J.; Carvalho, L. V.; Funk, C. C.; Husak, G. J.

    2010-12-01

    More than half the population of Guatemala lives in rural areas and depends on subsistence agriculture for their well being. This region is vulnerable to many climatic events, one of which is El Niño. This study looks at the effects of El Nino on rainfall patterns at regional scales and specifically quantifies the effects on agricultural water balances in Guatemala. Analysis is focused on maize crops during the Primera growing season (May - July). The study builds on rainfall and water balance modeling techniques developed by the Famine Early Warning Systems Network (FEWS NET). The results corroborate previous work, showing that there is a negative relationship between El Niño and rainfall, primarily on the Pacific side of the region and mainly during the months of August and September. The study also found that the related rainfall variations influence long-term (May - October) maize growing areas and could affect the start of the short-term Postrera season (August - October) by extending the Canícula. Correlation between rainfall and the Oceanic Niño Index (ONI) for the month of August in Central America.

  18. Growing wheat in Biosphere 2 under elevated CO2: observations and modeling

    NASA Technical Reports Server (NTRS)

    Tubiello, F. N.; Mahato, T.; Morton, T.; Druitt, J. W.; Volk, T.; Marino, B. D.

    1999-01-01

    Spring wheat (Triticum aestivum L., cv. Yecora Rojo) was grown in the intensive agricultural biome (IAB) of Biosphere 2 during the l995-l996 winter/spring season. Environmental conditions were characterized by a day/night temperature regime of 27/17 degrees C, relative humidity (RH) levels around 45%, mean atmospheric CO2 concentration of 450 ppmv, and natural light conditions with mean intensities about half of outside levels. Weekly samples of above-ground plant matter were collected throughout the growing season and phenological events recorded. A computer model, CERES-Wheat, previously tested under both field and controlled conditions, was used to simulate the observed crop growth and to help in data analysis. We found that CERES-Wheat simulated the data collected at Biosphere 2 to within 10% of observed, thus suggesting that wheat growth inside the IAB was comparable to that documented in other environments. The model predicts phenological stages and final dry matter (DM) production within l0% of the observed data. Measured DM production rates, normalized for light absorbed by the crop. suggested photosynthetic efficiencies intermediate between those observed under optimal field conditions and those recorded in NASA-Controlled Ecological Life-Support Systems (CELSS). We suggest that such a difference can be explained primarily in terms of low light levels inside the IAB, with additional effects due to elevated CO2 concentrations and diffuse light fractions.

  19. Growing wheat in Biosphere 2 under elevated CO2: observations and modeling.

    PubMed

    Tubiello, F N; Mahato, T; Morton, T; Druitt, J W; Volk, T; Marino, B D

    1999-01-01

    Spring wheat (Triticum aestivum L., cv. Yecora Rojo) was grown in the intensive agricultural biome (IAB) of Biosphere 2 during the l995-l996 winter/spring season. Environmental conditions were characterized by a day/night temperature regime of 27/17 degrees C, relative humidity (RH) levels around 45%, mean atmospheric CO2 concentration of 450 ppmv, and natural light conditions with mean intensities about half of outside levels. Weekly samples of above-ground plant matter were collected throughout the growing season and phenological events recorded. A computer model, CERES-Wheat, previously tested under both field and controlled conditions, was used to simulate the observed crop growth and to help in data analysis. We found that CERES-Wheat simulated the data collected at Biosphere 2 to within 10% of observed, thus suggesting that wheat growth inside the IAB was comparable to that documented in other environments. The model predicts phenological stages and final dry matter (DM) production within l0% of the observed data. Measured DM production rates, normalized for light absorbed by the crop. suggested photosynthetic efficiencies intermediate between those observed under optimal field conditions and those recorded in NASA-Controlled Ecological Life-Support Systems (CELSS). We suggest that such a difference can be explained primarily in terms of low light levels inside the IAB, with additional effects due to elevated CO2 concentrations and diffuse light fractions. PMID:11542248

  20. Applications of Remote Sensing to Precision Agriculture

    NASA Astrophysics Data System (ADS)

    Seielstad, G. A.; Laguette, S.; Seelan, S.; Lawrence, R.; Henry, M.; Maynard, C.; Dalsted, K.; Rattling Leaf, J.

    2001-05-01

    The Upper Midwest Aerospace Consortium (UMAC) has changed agricultural practices in the following ways: (1) farmers and ranchers have become partners with, not clients of, researchers; (2) experiments are carried out in the field rather than on small experimental plots; (3) the field is considered an agro-ecosystem, with all the complexities of multiple interactions, rather than attempting to isolate certain parameters and vary only a few; (4) both economic benefit to the producer and sound environmental stewardship for society are achievable. This approach has revealed that information is as significant an input to farm or ranch management as seeds, fertilizers, irrigation, and tillage. Accurate, timely information equips producers with the ability to make decisions during a growing season that optimize the yield at harvest time. An invaluable source of in-season information is imagery acquired from sensors on satellites or aircraft. In addition to sensing reflected sunlight in wavebands outside the visible, remote sensing's overview also reveals anomalous patterns in the vegetation cover that are difficult to spot on the ground. Anomalies can be caused by weeds, disease, water stress, inadequate nutrients, or other causes. Often, anomalies must be detected early or they spread too quickly to be addressed. The paper will demonstrate how remote sensing has been applied to (1) define management zones in farm fields, (2) prescribe variable rate applications of fertilizer, (3) detect pest infestations, and (4) manage cattle grazing according to forage available. The applications were possible because data were processed within 4-5 days of acquisition by the satellite, and then delivered by high-bandwidth satellite links to farmers, ranchers, and tribal government officials in minimal transit time. The applications research described was part of NASA's Synergy Program.

  1. Non-stationarity of "Nature's Limit" - Implications for Agriculture in Semi-arid Environments

    NASA Astrophysics Data System (ADS)

    Tozer, C.; Kiem, A.; Verdon-Kidd, D.

    2014-12-01

    "Rain follows the plow" was a theory that encouraged agricultural settlement in dryland areas in both the United States of America and Australia during the mid-1800s. Supporters of the theory believed that humans could master nature and alter the climate through cultivation of the soil. An opponent of this theory was George W. Goyder, who used vegetation in South Australia as an indicator to mark out the extent of the area's severe 1865 drought, effectively establishing "nature's limit" to reliable agriculture in South Australia. This limit became known as Goyder's Line and demarked the boundary between land suitable for agricultural pursuits (i.e. cropping) to the south and land only suitable for grazing in the State's arid north. Current cropping areas however extend north beyond this line, suggesting that either a) the line is not well defined, b) cropping is occurring on land considered 'non-viable' according to Goyder's Line or c) the line distinguishing where cropping is and is not viable varies on interannual to multidecadal timescales. In this study, the 220 mm growing season (April to October) rainfall isohyet is used as a proxy for Goyder's Line in ord