In a study comparing grain filling and yield in a large-and a small-grain-size wheat cultivar under two planting patterns and two irrigation regimes,plastic-covered ridge and furrow planting with sprinkler irrigation ...In a study comparing grain filling and yield in a large-and a small-grain-size wheat cultivar under two planting patterns and two irrigation regimes,plastic-covered ridge and furrow planting with sprinkler irrigation increased grain filling and yield in both cultivars.The largest contributors to grain yield were an extended active grain-filling period in Shuangda 1 and an increased mean grain-filling rate in XN538.展开更多
Soil information is one of the crucial inputs needed to assess the impacts of existing and alternative agricultural management practices on water quality. Therefore, it is important to understand the effects of spatia...Soil information is one of the crucial inputs needed to assess the impacts of existing and alternative agricultural management practices on water quality. Therefore, it is important to understand the effects of spatial scale at which soil databases are developed on water quality evaluations. In the United States, STATSGO (State Soils Geographic) and SSURGO (Soil Survey Geographic) are the most commonly available soil databases. The purpose of this paper was to quantify the effect of scale by employing STATSGO (1:250,000) and SSURGO (1:24,000) soil databases in predicting and comparing flow, sediment, nitrate and phosphorus losses for High Island Creek. This watershed is predominately agricultural and located in south-central Minnesota. The ADAPT (Agricultural Drainage and Pesticide Transport), model was calibrated for flow, sediment, nitrate and phosphorus losses over two years (2001-2002) using STATSGO and SSURGO soil databases. Then the calibrated model was used to evaluate alternative tillage and fertilizer management practices such as adoption of conservation tillage, and rate, timing and method of N- and P-fertilizer applications. Statistical comparison of calibration results with observed data indicated excellent agreement for both soil databases (STATSGO with r2 of 0.95, 0.97, 0.77 and 0.92 and SSURGO with r2 of 0.90, 0.97, 0.82 and 0.99 for flow, sediment, nitrate and phosphorus losses, respectively). However, STATSGO based predictions of annual nitrate-N losses were consistently greater than those with SSURGO database and vice-versa for predicted annual phosphorus losses for the alternative management practice that were evaluated.展开更多
Cotton yields in Uzbekistan are significantly lower than those in similar agro-climatic regions,requiring the estimation of crop potential and baseline yield to track progress of production enhancement efforts.The cur...Cotton yields in Uzbekistan are significantly lower than those in similar agro-climatic regions,requiring the estimation of crop potential and baseline yield to track progress of production enhancement efforts.The current study estimated potential cotton development and baseline yield(maximum given no production constraints)using total heat units(THU)and potential cotton yield(PCY),respectively.Calculations were based on heat units(HU)for a 30-year(1984-2013)period.Long-term average THU and PCY,as well as PCY at three different exceedance probabilities(p=0.99,p=0.80,and p=0.75),were calculated for 21 selected weather stations across cotton-growing areas of Uzbekistan.After confirmation that the current planting date(April 15)is optimal,a comparison of THU with the accepted cotton production cutoff threshold(1444°C)suggested that areas with lower elevations and latitudes are more appropriate for cotton production.Yield gap analysis(relative difference between long-term average PCY and actual yields)confirmed that Uzbekistan cotton production is below potential,while the spatial distribution of yield gaps outlined where efforts should be targeted.Areas near the stations of Nukus,Kungrad,Chimbay,and Syrdarya should be further investigated as benefit/cost ratio is highest in these areas.A comparison between state-set yield targets and PCY values,taking into account climatic variability,suggested that all areas except Jaslyk,Nurata,and Samarkand have safe,appropriate targets.These results present a starting-point to aid in strategic actions for Uzbekistan cotton production improvement.展开更多
Introduction:The lower Syr Darya River Basin is an integral part of the Aral Sea Basin that is shared by four riparian countries.In Kazakhstan,the water is mainly used for agricultural purposes.However,the poor qualit...Introduction:The lower Syr Darya River Basin is an integral part of the Aral Sea Basin that is shared by four riparian countries.In Kazakhstan,the water is mainly used for agricultural purposes.However,the poor quality and insufficient quantity of water and the overall degradation of natural resources due to unsustainable management practices threaten the profitability of the sector.The situation is even worse for downstream users.Three alternative scenarios for sustainable water and land management were developed using the RIOS and SWAT models as decision support tools.The scenario that offered the highest water and land productivity was presented to farmers to assess their willingness to forgo their current practices and adopt proposed management practices.We introduce willingness to forego(WTF)—a qualitative approach and a variant of the concept of opportunity costs to look beyond hypothetical markets to trading current benefits for future returns.We also tap into literature on agricultural risk management to provide additional insight into farmers’rationale behind their choices.Result:Generally,despite their stated preference to conserve ecosystem services,farmers’actions were found to be inconsistent with the proposed sustainable management.WTF analysis revealed that farmers’desire to maximize current benefits and more importantly to minimize future risks override all sustainability considerations.Their WTF current benefits mainly depended on their location along the canal and hence their access to water and land,overall cost of production,market conditions that informed their crop choices,and the cost of adopting recommended packages.While the results remain specific to this case,they are consistent with the literature that links farmers’behaviors to ecological performances.Conclusions:The study highlights the limitations of decision support tools and other valuation approaches including willingness to pay(WTP)and willingness to accept(payment)(WTA),to capture the delicate trade-offs that need to be considered to ensure household food and income security and encourage adoption of sustainable ecosystem management practices.Adequate information on potential effects of proposed conservation measures on yield,markets and hence farm profits,and availability of other alternatives are critical in shaping farmers’decisions.展开更多
In the dryland regions of North China,water is the limiting factor for rainfed crop production.Conservation agriculture(featuring reduced or zero tillage,mulching,crop rotations and cover crops)has been proposed to im...In the dryland regions of North China,water is the limiting factor for rainfed crop production.Conservation agriculture(featuring reduced or zero tillage,mulching,crop rotations and cover crops)has been proposed to improve soil and water conservation and enhance yields in these areas.Conservation agriculture systems typically result in increased crop water availability and agro-ecosystem productivity,and reduced soil erosion.To evaluate the potential of conservation agriculture to improve soil water balance and agricultural productivity,the DSSAT crop model was calibrated using the data of a field experiment in Shouyang County in the semi-arid northeastern part of the Yellow River Basin.The average annual precipitation at the site is 472 mm,75%of which falls during the growing season.The site had a maize-fallow-maize rotation.data from two crop seasons(2005 and 2006)and four treatments for calibration and analysis were used.The treatments were:conventional tillage(CT),no-till with straw mulching(NTSM),all-straw incorporated(ASRT)and one-third residue left on the surface with no-till(RRT).The calibration results gave satisfactory agreement between field observed and model predicted values for crop yield for all treatments except RRT treatment,and for soil water content of different layers in the 150 cm soil profile for all treatments.The difference between observed and predicted values was in the range of 3%-25%for maize yield and RMSE was in the range of 0.03-0.06 cm^(3)/cm^(3) for soil water content measured periodically each cropping season.While these results are encouraging,more rigorous calibration and independent model evaluation are warranted prior to making recommendations based on model simulations.Medium-term simulations(1995-2004)were conducted for three of the treatments using the calibrated model.The NTSM and ASRT treatments had similar or higher yields(by up to 36%),higher crop water productivity by up to 28%and reduced runoff of up to 93%or 43 mm compared to CT treatment.展开更多
In order to improve water quality and restore impaired watersheds,managers need to make decisions using data that are able to gather.Data collection can be expensive,tedious and time consuming.Not all watershed manage...In order to improve water quality and restore impaired watersheds,managers need to make decisions using data that are able to gather.Data collection can be expensive,tedious and time consuming.Not all watershed managers have sufficient budgets to undertake such exercises.In such situations using modeling approach makes sense.The Sediment Nutrient Assessment Program(SNAP)is a functionally distributed model.It uses Geographic Information System(GIS)-based methodology employing commonly used Revised Universal Soil Loss Equation(RUSLE)to estimate the amount of erosion that can occur in the study area and Flux model for estimating the sediment transport.By adopting this methodology a modeler can estimate fractions of sediment contributions from the three landforms(upland,surface tiled,riparian).An intermediate result is mapping of areas producing erosion at rates above,below and equal to tolerable rates for each soil type.The model works best on smaller watersheds(<4,000 hectare)where staff have time and resources to inventory water quality.A good understanding of the watershed is needed to validate the model outputs.The model implementation is relatively cheap,cost effective and easy.Existing data and freely available information in the public domain are used for computations.It takes a multifaceted and holistic approach by integrating current,localized research literature,field surveys,water quality data,and GIS into one tool for refining watershed management decisions.The SNAP model serves as a first stage of analyzing as to how bad the sedimentation problem is with limited resources.展开更多
基金supported by the National Key Research and Development Program of China(2017YFD0300202-2)the National Natural Science Foundation of China(31871567)the Young Scholar of Tang(2017)。
文摘In a study comparing grain filling and yield in a large-and a small-grain-size wheat cultivar under two planting patterns and two irrigation regimes,plastic-covered ridge and furrow planting with sprinkler irrigation increased grain filling and yield in both cultivars.The largest contributors to grain yield were an extended active grain-filling period in Shuangda 1 and an increased mean grain-filling rate in XN538.
基金国家科技支撑计划课题"农田水分生产潜力及适度开发研究"(2006BAD29B01)Challenge Program on Water & Food"Conservation agriculture for the dry-land areas of the Yellow River Basin"+1 种基金国家"十一五"863课题"山西半干旱区现代节水农业技术集成基地("2006AA100220)农业部"保护性耕作对地力及作物生长影响的机理研究"
基金Challenge Program on Water&Food"Conservation Agriculture for the Dryland Areas of the Yellow River Basin"(CN228)"十一五"国家科技支撑计划项目"黄土高原水土流失综合治理工程关键支撑技术研究"(2006BAD09B04)欧盟DESIRE项目(037046)
文摘Soil information is one of the crucial inputs needed to assess the impacts of existing and alternative agricultural management practices on water quality. Therefore, it is important to understand the effects of spatial scale at which soil databases are developed on water quality evaluations. In the United States, STATSGO (State Soils Geographic) and SSURGO (Soil Survey Geographic) are the most commonly available soil databases. The purpose of this paper was to quantify the effect of scale by employing STATSGO (1:250,000) and SSURGO (1:24,000) soil databases in predicting and comparing flow, sediment, nitrate and phosphorus losses for High Island Creek. This watershed is predominately agricultural and located in south-central Minnesota. The ADAPT (Agricultural Drainage and Pesticide Transport), model was calibrated for flow, sediment, nitrate and phosphorus losses over two years (2001-2002) using STATSGO and SSURGO soil databases. Then the calibrated model was used to evaluate alternative tillage and fertilizer management practices such as adoption of conservation tillage, and rate, timing and method of N- and P-fertilizer applications. Statistical comparison of calibration results with observed data indicated excellent agreement for both soil databases (STATSGO with r2 of 0.95, 0.97, 0.77 and 0.92 and SSURGO with r2 of 0.90, 0.97, 0.82 and 0.99 for flow, sediment, nitrate and phosphorus losses, respectively). However, STATSGO based predictions of annual nitrate-N losses were consistently greater than those with SSURGO database and vice-versa for predicted annual phosphorus losses for the alternative management practice that were evaluated.
基金the CGIAR Research Program on Dryland Systems led by the International Center for Agricultural Research in the Dry Areas(ICARDA).Dryland Systems is supported by these donors(http://drylandsystems.cgiar.org/partner-focus).
文摘Cotton yields in Uzbekistan are significantly lower than those in similar agro-climatic regions,requiring the estimation of crop potential and baseline yield to track progress of production enhancement efforts.The current study estimated potential cotton development and baseline yield(maximum given no production constraints)using total heat units(THU)and potential cotton yield(PCY),respectively.Calculations were based on heat units(HU)for a 30-year(1984-2013)period.Long-term average THU and PCY,as well as PCY at three different exceedance probabilities(p=0.99,p=0.80,and p=0.75),were calculated for 21 selected weather stations across cotton-growing areas of Uzbekistan.After confirmation that the current planting date(April 15)is optimal,a comparison of THU with the accepted cotton production cutoff threshold(1444°C)suggested that areas with lower elevations and latitudes are more appropriate for cotton production.Yield gap analysis(relative difference between long-term average PCY and actual yields)confirmed that Uzbekistan cotton production is below potential,while the spatial distribution of yield gaps outlined where efforts should be targeted.Areas near the stations of Nukus,Kungrad,Chimbay,and Syrdarya should be further investigated as benefit/cost ratio is highest in these areas.A comparison between state-set yield targets and PCY values,taking into account climatic variability,suggested that all areas except Jaslyk,Nurata,and Samarkand have safe,appropriate targets.These results present a starting-point to aid in strategic actions for Uzbekistan cotton production improvement.
基金This study was funded by the CGIAR Research Program on Water,Land and Ecosystems(WLE)and is a result of a collaborative research by the International Center for Agricultural Research in the Dry Areas(ICARDA)and the Regional Environmental Center for Central Asia(CAREC).
文摘Introduction:The lower Syr Darya River Basin is an integral part of the Aral Sea Basin that is shared by four riparian countries.In Kazakhstan,the water is mainly used for agricultural purposes.However,the poor quality and insufficient quantity of water and the overall degradation of natural resources due to unsustainable management practices threaten the profitability of the sector.The situation is even worse for downstream users.Three alternative scenarios for sustainable water and land management were developed using the RIOS and SWAT models as decision support tools.The scenario that offered the highest water and land productivity was presented to farmers to assess their willingness to forgo their current practices and adopt proposed management practices.We introduce willingness to forego(WTF)—a qualitative approach and a variant of the concept of opportunity costs to look beyond hypothetical markets to trading current benefits for future returns.We also tap into literature on agricultural risk management to provide additional insight into farmers’rationale behind their choices.Result:Generally,despite their stated preference to conserve ecosystem services,farmers’actions were found to be inconsistent with the proposed sustainable management.WTF analysis revealed that farmers’desire to maximize current benefits and more importantly to minimize future risks override all sustainability considerations.Their WTF current benefits mainly depended on their location along the canal and hence their access to water and land,overall cost of production,market conditions that informed their crop choices,and the cost of adopting recommended packages.While the results remain specific to this case,they are consistent with the literature that links farmers’behaviors to ecological performances.Conclusions:The study highlights the limitations of decision support tools and other valuation approaches including willingness to pay(WTP)and willingness to accept(payment)(WTA),to capture the delicate trade-offs that need to be considered to ensure household food and income security and encourage adoption of sustainable ecosystem management practices.Adequate information on potential effects of proposed conservation measures on yield,markets and hence farm profits,and availability of other alternatives are critical in shaping farmers’decisions.
基金the 11th Five-year plan of National Key Technologies R&D Program:“Water Balance and Crop Potential Productivity in Field Scale(No.2006BAD29B01)”the 11th Five-year plan of National High-tech R&D Program:“The Pilot Base Construction of Modern Water Saving Technology of Agriculture in Shanxi province(No.2006AA100220)”“The study on the mechanism of the effect of conservation agriculture for field fertility and crop growing”from Ministry of Agriculture,China.
文摘In the dryland regions of North China,water is the limiting factor for rainfed crop production.Conservation agriculture(featuring reduced or zero tillage,mulching,crop rotations and cover crops)has been proposed to improve soil and water conservation and enhance yields in these areas.Conservation agriculture systems typically result in increased crop water availability and agro-ecosystem productivity,and reduced soil erosion.To evaluate the potential of conservation agriculture to improve soil water balance and agricultural productivity,the DSSAT crop model was calibrated using the data of a field experiment in Shouyang County in the semi-arid northeastern part of the Yellow River Basin.The average annual precipitation at the site is 472 mm,75%of which falls during the growing season.The site had a maize-fallow-maize rotation.data from two crop seasons(2005 and 2006)and four treatments for calibration and analysis were used.The treatments were:conventional tillage(CT),no-till with straw mulching(NTSM),all-straw incorporated(ASRT)and one-third residue left on the surface with no-till(RRT).The calibration results gave satisfactory agreement between field observed and model predicted values for crop yield for all treatments except RRT treatment,and for soil water content of different layers in the 150 cm soil profile for all treatments.The difference between observed and predicted values was in the range of 3%-25%for maize yield and RMSE was in the range of 0.03-0.06 cm^(3)/cm^(3) for soil water content measured periodically each cropping season.While these results are encouraging,more rigorous calibration and independent model evaluation are warranted prior to making recommendations based on model simulations.Medium-term simulations(1995-2004)were conducted for three of the treatments using the calibrated model.The NTSM and ASRT treatments had similar or higher yields(by up to 36%),higher crop water productivity by up to 28%and reduced runoff of up to 93%or 43 mm compared to CT treatment.
文摘In order to improve water quality and restore impaired watersheds,managers need to make decisions using data that are able to gather.Data collection can be expensive,tedious and time consuming.Not all watershed managers have sufficient budgets to undertake such exercises.In such situations using modeling approach makes sense.The Sediment Nutrient Assessment Program(SNAP)is a functionally distributed model.It uses Geographic Information System(GIS)-based methodology employing commonly used Revised Universal Soil Loss Equation(RUSLE)to estimate the amount of erosion that can occur in the study area and Flux model for estimating the sediment transport.By adopting this methodology a modeler can estimate fractions of sediment contributions from the three landforms(upland,surface tiled,riparian).An intermediate result is mapping of areas producing erosion at rates above,below and equal to tolerable rates for each soil type.The model works best on smaller watersheds(<4,000 hectare)where staff have time and resources to inventory water quality.A good understanding of the watershed is needed to validate the model outputs.The model implementation is relatively cheap,cost effective and easy.Existing data and freely available information in the public domain are used for computations.It takes a multifaceted and holistic approach by integrating current,localized research literature,field surveys,water quality data,and GIS into one tool for refining watershed management decisions.The SNAP model serves as a first stage of analyzing as to how bad the sedimentation problem is with limited resources.