Scarcity of rainfall and limited irrigation water resources is the main challenge for agricultural expanding policies and strategies. At the same time, there is a high concern to increase the area of wheat cultivation...Scarcity of rainfall and limited irrigation water resources is the main challenge for agricultural expanding policies and strategies. At the same time, there is a high concern to increase the area of wheat cultivation in order to meet the increasing local consumption. The big challenge is to incerese wheat production using same or less amount of irrigation water. In this trend, the study was carried out to analyze the sensitivity of wheat yield to water deficit using remotely sensed data in El-Salhia agricultural project which located in the eastern part of Nile delta. Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) were extracted from Landsat 7. Water Deficit Index (WDI) used both LST minus air temperature (Tair) and vegetation index to estimate the relative water status. Yield response factor (ky) was derived from relationship between relative yield decrease and relative evapotranspiration deficit. The relative Evapotranspiration deficit was replaced by WDI. Linear regression was found between predicted wheat yield and actual wheat yield with 0.2?6, 0.025, 0.252 and 0.76 as correlation coefficient on 30th of Dec. 2012, 15th of Jan. 2013, 16th of Feb. 2013 and 20th of Mar. 2013 respectively. The main objective of this study is using a combination between FAO 33 paper approach and remote sensing techniques to estimate wheat yield response to water.展开更多
The water deficit in arid and semi-arid regions is the primary limiting factor for the development of urban greenery and forestation. In addition, planting the species that consume low levels of water is useful in ari...The water deficit in arid and semi-arid regions is the primary limiting factor for the development of urban greenery and forestation. In addition, planting the species that consume low levels of water is useful in arid and semi-arid regions that have poor water management measures. Leaf water potential(Ψ) is a physiological parameter that can be used to identify drought resistance in various species. Indeed, Ψ is one of the most important properties of a plant that can be measured using a pressure chamber. Drought avoiding or drought resistant species have a lower Ψ than plants that use normal or high levels of water. To determine drought resistance of species that are suitable for afforestation in arid urban regions, we evaluated twenty woody species in the Isfahan City, central Iran. The experimental design was random split-split plots with five replications. The species were planted outdoor in plastic pots and then subjected to treatments that consisted of two soil types and five drip irrigation regimes. To evaluate the resistance of each species to drought, we used the Ψ and the number of survived plants to obtain the drought resistance index(DRI). Then, cluster analysis, dendrogram, and similarity index were used to group the species using DRI. Result indicates that the evaluated species were classified into five groups:(1) high water consuming species(DRI>–60 MPa);(2) above normal water consuming species(–60 MPa≥DRI>–90 MPa);(3) normal water consuming species(–90 MPa≥DRI>–120 MPa);(4) semi-drought resistant species(–120 MPa≥DRI>–150 MPa);and(5) drought resistant species(DRI≤–150 MPa). According to the DRI, Salix babylonica L., Populus alba L., and P. nigra L. are high water consuming species, Platanus orientalis L. and Albizia julibrissin Benth are normal water consuming species, and Quercus infectoria Oliv. and Olea europaea L. can be considered as drought resistant species.展开更多
作为西南地区主要的水稻产区,成都平原近年来面临日益严重的干旱问题。为确定该地区水稻最适宜的播种时期,提高抗旱能力,本文以广汉地区为例,采用气候倾向率法分析1991—2020年不同播期水稻生育期的气候资源特征,并通过作物水分亏缺指数...作为西南地区主要的水稻产区,成都平原近年来面临日益严重的干旱问题。为确定该地区水稻最适宜的播种时期,提高抗旱能力,本文以广汉地区为例,采用气候倾向率法分析1991—2020年不同播期水稻生育期的气候资源特征,并通过作物水分亏缺指数(Crop Water Deficit Index,CWDI)评估水稻生育期的干旱程度。结果表明,近30 a来研究区各播期水稻的气候特征均表现为日照减少、日均温上升、降水量增加的趋势。随播期推迟,水稻全生育期日照时数整体减少,日均温、降水量均呈上升和增加趋势。CWDI随水稻发育逐渐减小,各播期水稻在生育前、中期缺水率较高。不同播期水稻生长期内均以轻旱、中旱为主,其次是重旱,特旱最少。研究区3月下旬至4月初的气候资源配置最优,是最适宜水稻播种的时期;3月上旬及中旬播种应选择抗旱品种,而4月中下旬播种则需防范重旱对作物需水期的影响。展开更多
【目的】干旱是影响中国农业生产的主要自然灾害之一。东北地区作为中国最大的玉米生产基地,气候变化背景下干旱频发重发严重影响玉米的高产稳产。评估未来气候情景下东北地区春玉米干旱发生风险及其空间格局变化,为该地区春玉米防旱避...【目的】干旱是影响中国农业生产的主要自然灾害之一。东北地区作为中国最大的玉米生产基地,气候变化背景下干旱频发重发严重影响玉米的高产稳产。评估未来气候情景下东北地区春玉米干旱发生风险及其空间格局变化,为该地区春玉米防旱避灾以及保障其高产稳产提供科学依据。【方法】选取东北地区春玉米潜在种植区为研究区域,基于ISIMIP输出的SSP1-2.6、SSP3-7.0和SSP5-8.53种气候情景的1981—2060年逐日气象资料以及53个农业气象观测站1981—2014年春玉米生育期资料,选取作物水分亏缺指数(crop water deficit index,CWDI)为农业干旱指标,分析东北地区春玉米不同生育时期不同等级干旱时空分布特征,选择最优概率理论分布函数进行干旱指数序列的概率估算,基于信息扩散理论估算得到各点春玉米不同等级干旱风险,构建干旱风险指数,评估未来不同气候情景下东北地区春玉米干旱发生风险及未来各等级风险区的空间格局变化。【结果】(1)1981—2014年东北地区春玉米全生育期干旱指数总体呈西南高东北低的特征,表现为内蒙古东四盟(57.3%)>黑龙江省(40.6%)>辽宁省(39.5%)>吉林省(38.9%)。(2)研究区域春玉米生育中期干旱指数整体高于生育前期和生育后期。其中,2030s和2050s研究区域春玉米生育前期干旱风险概率为轻旱>中旱≈重旱>特旱,生育中期干旱风险概率为特旱>重旱>轻旱≈中旱,生育后期干旱风险概率轻旱>中旱>重旱>特旱。(3)1981—2060年,SSP1-2.6低排放情景下,东北地区春玉米较高等级干旱风险发生概率将减少,极高和较高干旱风险区明显向西南收缩,2030s和2050s面积占比分别减少5.4%和9.6%、0.8%和2.5%;而SSP3-7.0和SSP5-8.5两个高排放情景下,较高等级干旱风险发生概率增加,且较高干旱风险区向东北扩张,2050s面积占比分别增加8.5%和9.7%。【结论】基于干旱风险指数的未来干旱风险时空分布格局中,东北春玉米干旱风险呈现由西南向东北减少的特征,且未来SSP3-7.0和SSP5-8.5情景下,较高干旱风险区向东北方向扩张,需关注作物关键生育时期提出针对性的防御措施。展开更多
【目的】探究马铃薯的叶气温差与环境因子的关系,进一步优化马铃薯水分胁迫指数模型。【方法】在河南农业大学林学院试验基地进行马铃薯盆栽试验,选择晴朗天气测定不同土壤含水率下马铃薯的叶气温差随太阳辐射和大气饱和水汽压差(VPD)...【目的】探究马铃薯的叶气温差与环境因子的关系,进一步优化马铃薯水分胁迫指数模型。【方法】在河南农业大学林学院试验基地进行马铃薯盆栽试验,选择晴朗天气测定不同土壤含水率下马铃薯的叶气温差随太阳辐射和大气饱和水汽压差(VPD)的变化规律,确定作物水分胁迫指数(crop water stress index,CWSI)的上下基线,进一步试验后得到优化后的马铃薯CWSI经验模型,并对相关模型进行验证。【结果】马铃薯的叶气温差随着土壤含水率的降低而升高;当土壤含水率较低(7.28%)时,马铃薯的叶气温差随太阳辐射的增大而增大,呈显著线性关系;当土壤含水率较高(15.85%)时,马铃薯的叶气温差随VPD的增大而减小,呈显著线性关系;构建出马铃薯CWSI的上基线为y=0.0098Q-0.68[Q为太阳辐射强度/(W·m^(-2))],下基线为y=-1.67V+3.75(V为大气饱和水汽压差/kPa);将优化的CWSI模型验证后得知,随着土壤含水率的减少,CWSI值增加,且CWSI同土壤含水量呈极显著负相关关系(p<0.01)。【结论】马铃薯的最大叶气温差与太阳辐射的线性关系作为马铃薯水分胁迫指数的上基线是可行的,该研究对传统CWSI经验模型进行改进,进一步优化了CWSI经验模型。展开更多
Biomass accumulation and partitioning into different plant parts is a dynamic process during the plant growing period, which is influenced by crop management and climate factors. Adequate knowledge of biomass partitio...Biomass accumulation and partitioning into different plant parts is a dynamic process during the plant growing period, which is influenced by crop management and climate factors. Adequate knowledge of biomass partitioning is important to manage the crops to gain maximum partitioning of assimilates into plant parts of economic significance, i.e. tubers in potato. This study was conducted using two potato cultivars grown in a sandy soil with center pivot irrigation under full irrigation (FI;irrigation to replenish 100% of water loss by evapotranspiration [ET]) and deficit irrigation (DI;replenish only 80% ET) and two nitrogen(N) rates (pre-plant + in-seasonN rates of 56 + 112 or 168 + 336 kg/ha). Plant samples were taken on 22, 44, 66, and 98 days after seedling emergence (DAE). With high N rate, tuber biomass of ‘Umatilla Russet’ cultivar in relation to total plant biomass varied from 23% - 88% and 25% - 86% over 22 to 98 DAE for the FI and DI treatments, respectively. The corresponding partitioning ranges were 30% - 93% and 38% - 93% at the low N rate. With respect to the‘Ranger Russet’ cultivar, biomass partitioning to tubers ranged from 36% - 82% and 23% - 84% for the FI and DI, respectively, at the high N rate, and 29% - 87% and 39% - 95% at the low N rate. Overall, this study demonstrated that within the range of N rate and irrigation treatments the biomass portioning into tubers was largely similar in both cultivars.展开更多
基于黑龙江省62个气象台站1961-2019年逐日气象资料,利用联合国粮农组织(FAO)推荐的方法计算大豆需水量,应用美国农业部土壤保持局推荐的方法计算有效降水,采用M-K检验、GIS反距离加权插值等方法分析黑龙江省大豆各生育阶段水分盈亏指...基于黑龙江省62个气象台站1961-2019年逐日气象资料,利用联合国粮农组织(FAO)推荐的方法计算大豆需水量,应用美国农业部土壤保持局推荐的方法计算有效降水,采用M-K检验、GIS反距离加权插值等方法分析黑龙江省大豆各生育阶段水分盈亏指数及干旱与洪涝演变特征。结果表明:黑龙江省大豆生长季内有效降水在开花以前主要呈增加趋势,开花及以后主要呈减少趋势;大豆需水量在第三真叶期以前主要呈增加趋势,第三真叶期及以后呈减少趋势,结荚-鼓粒期和鼓粒-成熟期减少趋势最为显著。大豆生长季内水分盈亏指数(Crop water surplus deficit index,CWSDI)中部偏东地区和最北部地区最高,东部高于西部;开花-结荚期和结荚-鼓粒期CWSDI最低,鼓粒-成熟期最高。洪涝多发于偏北部地区,东部多于西部,出苗-第三真叶期洪涝发生站次最多。干旱发生频次高于洪涝,西部或西南部干旱发生频率高于东部,中部和北部最低,干旱多发生于开花-鼓粒期。展开更多
文摘Scarcity of rainfall and limited irrigation water resources is the main challenge for agricultural expanding policies and strategies. At the same time, there is a high concern to increase the area of wheat cultivation in order to meet the increasing local consumption. The big challenge is to incerese wheat production using same or less amount of irrigation water. In this trend, the study was carried out to analyze the sensitivity of wheat yield to water deficit using remotely sensed data in El-Salhia agricultural project which located in the eastern part of Nile delta. Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) were extracted from Landsat 7. Water Deficit Index (WDI) used both LST minus air temperature (Tair) and vegetation index to estimate the relative water status. Yield response factor (ky) was derived from relationship between relative yield decrease and relative evapotranspiration deficit. The relative Evapotranspiration deficit was replaced by WDI. Linear regression was found between predicted wheat yield and actual wheat yield with 0.2?6, 0.025, 0.252 and 0.76 as correlation coefficient on 30th of Dec. 2012, 15th of Jan. 2013, 16th of Feb. 2013 and 20th of Mar. 2013 respectively. The main objective of this study is using a combination between FAO 33 paper approach and remote sensing techniques to estimate wheat yield response to water.
文摘The water deficit in arid and semi-arid regions is the primary limiting factor for the development of urban greenery and forestation. In addition, planting the species that consume low levels of water is useful in arid and semi-arid regions that have poor water management measures. Leaf water potential(Ψ) is a physiological parameter that can be used to identify drought resistance in various species. Indeed, Ψ is one of the most important properties of a plant that can be measured using a pressure chamber. Drought avoiding or drought resistant species have a lower Ψ than plants that use normal or high levels of water. To determine drought resistance of species that are suitable for afforestation in arid urban regions, we evaluated twenty woody species in the Isfahan City, central Iran. The experimental design was random split-split plots with five replications. The species were planted outdoor in plastic pots and then subjected to treatments that consisted of two soil types and five drip irrigation regimes. To evaluate the resistance of each species to drought, we used the Ψ and the number of survived plants to obtain the drought resistance index(DRI). Then, cluster analysis, dendrogram, and similarity index were used to group the species using DRI. Result indicates that the evaluated species were classified into five groups:(1) high water consuming species(DRI>–60 MPa);(2) above normal water consuming species(–60 MPa≥DRI>–90 MPa);(3) normal water consuming species(–90 MPa≥DRI>–120 MPa);(4) semi-drought resistant species(–120 MPa≥DRI>–150 MPa);and(5) drought resistant species(DRI≤–150 MPa). According to the DRI, Salix babylonica L., Populus alba L., and P. nigra L. are high water consuming species, Platanus orientalis L. and Albizia julibrissin Benth are normal water consuming species, and Quercus infectoria Oliv. and Olea europaea L. can be considered as drought resistant species.
文摘作为西南地区主要的水稻产区,成都平原近年来面临日益严重的干旱问题。为确定该地区水稻最适宜的播种时期,提高抗旱能力,本文以广汉地区为例,采用气候倾向率法分析1991—2020年不同播期水稻生育期的气候资源特征,并通过作物水分亏缺指数(Crop Water Deficit Index,CWDI)评估水稻生育期的干旱程度。结果表明,近30 a来研究区各播期水稻的气候特征均表现为日照减少、日均温上升、降水量增加的趋势。随播期推迟,水稻全生育期日照时数整体减少,日均温、降水量均呈上升和增加趋势。CWDI随水稻发育逐渐减小,各播期水稻在生育前、中期缺水率较高。不同播期水稻生长期内均以轻旱、中旱为主,其次是重旱,特旱最少。研究区3月下旬至4月初的气候资源配置最优,是最适宜水稻播种的时期;3月上旬及中旬播种应选择抗旱品种,而4月中下旬播种则需防范重旱对作物需水期的影响。
文摘【目的】干旱是影响中国农业生产的主要自然灾害之一。东北地区作为中国最大的玉米生产基地,气候变化背景下干旱频发重发严重影响玉米的高产稳产。评估未来气候情景下东北地区春玉米干旱发生风险及其空间格局变化,为该地区春玉米防旱避灾以及保障其高产稳产提供科学依据。【方法】选取东北地区春玉米潜在种植区为研究区域,基于ISIMIP输出的SSP1-2.6、SSP3-7.0和SSP5-8.53种气候情景的1981—2060年逐日气象资料以及53个农业气象观测站1981—2014年春玉米生育期资料,选取作物水分亏缺指数(crop water deficit index,CWDI)为农业干旱指标,分析东北地区春玉米不同生育时期不同等级干旱时空分布特征,选择最优概率理论分布函数进行干旱指数序列的概率估算,基于信息扩散理论估算得到各点春玉米不同等级干旱风险,构建干旱风险指数,评估未来不同气候情景下东北地区春玉米干旱发生风险及未来各等级风险区的空间格局变化。【结果】(1)1981—2014年东北地区春玉米全生育期干旱指数总体呈西南高东北低的特征,表现为内蒙古东四盟(57.3%)>黑龙江省(40.6%)>辽宁省(39.5%)>吉林省(38.9%)。(2)研究区域春玉米生育中期干旱指数整体高于生育前期和生育后期。其中,2030s和2050s研究区域春玉米生育前期干旱风险概率为轻旱>中旱≈重旱>特旱,生育中期干旱风险概率为特旱>重旱>轻旱≈中旱,生育后期干旱风险概率轻旱>中旱>重旱>特旱。(3)1981—2060年,SSP1-2.6低排放情景下,东北地区春玉米较高等级干旱风险发生概率将减少,极高和较高干旱风险区明显向西南收缩,2030s和2050s面积占比分别减少5.4%和9.6%、0.8%和2.5%;而SSP3-7.0和SSP5-8.5两个高排放情景下,较高等级干旱风险发生概率增加,且较高干旱风险区向东北扩张,2050s面积占比分别增加8.5%和9.7%。【结论】基于干旱风险指数的未来干旱风险时空分布格局中,东北春玉米干旱风险呈现由西南向东北减少的特征,且未来SSP3-7.0和SSP5-8.5情景下,较高干旱风险区向东北方向扩张,需关注作物关键生育时期提出针对性的防御措施。
文摘【目的】探究马铃薯的叶气温差与环境因子的关系,进一步优化马铃薯水分胁迫指数模型。【方法】在河南农业大学林学院试验基地进行马铃薯盆栽试验,选择晴朗天气测定不同土壤含水率下马铃薯的叶气温差随太阳辐射和大气饱和水汽压差(VPD)的变化规律,确定作物水分胁迫指数(crop water stress index,CWSI)的上下基线,进一步试验后得到优化后的马铃薯CWSI经验模型,并对相关模型进行验证。【结果】马铃薯的叶气温差随着土壤含水率的降低而升高;当土壤含水率较低(7.28%)时,马铃薯的叶气温差随太阳辐射的增大而增大,呈显著线性关系;当土壤含水率较高(15.85%)时,马铃薯的叶气温差随VPD的增大而减小,呈显著线性关系;构建出马铃薯CWSI的上基线为y=0.0098Q-0.68[Q为太阳辐射强度/(W·m^(-2))],下基线为y=-1.67V+3.75(V为大气饱和水汽压差/kPa);将优化的CWSI模型验证后得知,随着土壤含水率的减少,CWSI值增加,且CWSI同土壤含水量呈极显著负相关关系(p<0.01)。【结论】马铃薯的最大叶气温差与太阳辐射的线性关系作为马铃薯水分胁迫指数的上基线是可行的,该研究对传统CWSI经验模型进行改进,进一步优化了CWSI经验模型。
文摘Biomass accumulation and partitioning into different plant parts is a dynamic process during the plant growing period, which is influenced by crop management and climate factors. Adequate knowledge of biomass partitioning is important to manage the crops to gain maximum partitioning of assimilates into plant parts of economic significance, i.e. tubers in potato. This study was conducted using two potato cultivars grown in a sandy soil with center pivot irrigation under full irrigation (FI;irrigation to replenish 100% of water loss by evapotranspiration [ET]) and deficit irrigation (DI;replenish only 80% ET) and two nitrogen(N) rates (pre-plant + in-seasonN rates of 56 + 112 or 168 + 336 kg/ha). Plant samples were taken on 22, 44, 66, and 98 days after seedling emergence (DAE). With high N rate, tuber biomass of ‘Umatilla Russet’ cultivar in relation to total plant biomass varied from 23% - 88% and 25% - 86% over 22 to 98 DAE for the FI and DI treatments, respectively. The corresponding partitioning ranges were 30% - 93% and 38% - 93% at the low N rate. With respect to the‘Ranger Russet’ cultivar, biomass partitioning to tubers ranged from 36% - 82% and 23% - 84% for the FI and DI, respectively, at the high N rate, and 29% - 87% and 39% - 95% at the low N rate. Overall, this study demonstrated that within the range of N rate and irrigation treatments the biomass portioning into tubers was largely similar in both cultivars.
文摘基于黑龙江省62个气象台站1961-2019年逐日气象资料,利用联合国粮农组织(FAO)推荐的方法计算大豆需水量,应用美国农业部土壤保持局推荐的方法计算有效降水,采用M-K检验、GIS反距离加权插值等方法分析黑龙江省大豆各生育阶段水分盈亏指数及干旱与洪涝演变特征。结果表明:黑龙江省大豆生长季内有效降水在开花以前主要呈增加趋势,开花及以后主要呈减少趋势;大豆需水量在第三真叶期以前主要呈增加趋势,第三真叶期及以后呈减少趋势,结荚-鼓粒期和鼓粒-成熟期减少趋势最为显著。大豆生长季内水分盈亏指数(Crop water surplus deficit index,CWSDI)中部偏东地区和最北部地区最高,东部高于西部;开花-结荚期和结荚-鼓粒期CWSDI最低,鼓粒-成熟期最高。洪涝多发于偏北部地区,东部多于西部,出苗-第三真叶期洪涝发生站次最多。干旱发生频次高于洪涝,西部或西南部干旱发生频率高于东部,中部和北部最低,干旱多发生于开花-鼓粒期。
