为提高中国三大灌区(都江堰灌区、河套灌区和淠史杭灌区)参考作物蒸散量(reference crop evapotranspiration,ET_0)温度法的计算精度,选取8个代表性站点1961-2014年逐日气象资料,采用Irmark-Allen(IA)、Hargreaves and Samani(HS)、Turc...为提高中国三大灌区(都江堰灌区、河套灌区和淠史杭灌区)参考作物蒸散量(reference crop evapotranspiration,ET_0)温度法的计算精度,选取8个代表性站点1961-2014年逐日气象资料,采用Irmark-Allen(IA)、Hargreaves and Samani(HS)、Turc(Tur)、Mc Cloud(MC)、Schendel(Sch)、Trajkovic(Tra)、Droogres and Allen-1(DA-1)和Droogres and Allen-2(DA-2)共8种温度法计算ET_0,以FAO-56Penman-Monteith(PM)法计算结果为标准,基于各方法计算的ET0日值线性回归方程(y=kx+b),分别在都江堰灌区选取IA法和Tra法,河套灌区选取HS法、DA-1法和DA-2法,淠史杭灌区选取IA法、HS法、DA-1法和DA-2法,引入调差参数对模型进行修订,利用均方根误差(RMSE)、平均相对误差(MRE)和Nash-Sutcliffe系数(NS)对其适应性进行评价。结果表明:都江堰灌区和淠史杭灌区所选模型修订后计算精度均有明显提高,河套灌区提高不明显;都江堰灌区IA修订模型(IA-Du法)在该灌区计算精度最高,其日值、旬值的RMSE、MRE和NS分别为0.318mm·d^(-1)、0.120和0.923,0.201mm·d^(-1)、0.093和0.959,且在不同月份均有较高计算精度;河套灌区计算精度最高模型为HS法,其日值、旬值的RMSE、MRE和NS分别为0.898mm·d^(-1)、0.326和0.785,0.547mm·d^(-1)、0.223和0.904,且在1-5月和10-12月具有较高计算精度;淠史杭灌区IA修订模型(IA-Pi法)在该灌区计算精度最高,其日值、旬值的RMSE、MRE和NS分别为0.534mm·d^(-1)、0.195和0.861,0.390mm·d^(-1)、0.167和0.896,且在不同月份均具有较高计算精度。因此,推荐IA-Du法、HS法和IA-Pi法分别作为都江堰灌区、河套灌区和淠史杭灌区计算参考作物蒸散量的方法。展开更多
We conducted a two-year study of deficit irrigation impact on peach yield and quality in semi-arid northwest China. Over two years, four-year-old peach trees were irrigated at 100, 75, 50 and 25% of peach evapotranspi...We conducted a two-year study of deficit irrigation impact on peach yield and quality in semi-arid northwest China. Over two years, four-year-old peach trees were irrigated at 100, 75, 50 and 25% of peach evapotranspiration （ETc）, here, ETc= Coefficient （Kc）×Local reference evapotranspiration （ET0）. During the April-July fruit production season we measured root zone soil water depletion, sap flow velocity, net photosynthetic rate （Pn）, transpiration rate （Tr）, stomatal conductance （Gs）, water use efficiency （WUE=Pn/Tr）, fruit quality, and yield under a mobile rain-out shelter. Increased soil water depletion reasonably mirrored decreasing irrigation rates both years, causing progressively greater water stress. Progressive water stress lowered Gs, which in turn translated into lower T as measured by sap flow. However, mild deficit irrigation （75% ETc） constricted T more than Pn. Pn was not different between 100 and 75% ETc treatments in both years, and it decreased only 5-8% in June with higher temperature than that in May with cooler temperature. Concurrently under 75% ETc treatment, was reduced, and WUE was up to 13% higher than that under 100% ETc treatment. While total fruit yield was not different under the two treatments, because 75% ETc treatment had fewer but larger fruit than 100% ETc trees, suggesting mild water stress thinned fruit load. By contrast, sharply decreased T and Pn of the driest treatments （50 and 25% ETo） increased WUE, but less carbon uptake impacted total fruit yield, resulting 13 and 33% lower yield compared to that of 100% ETc treatment. Irrigation rates affected fruit quality, particularly between the 100 and 75% ETc trees. Fewer but larger fruit in the mildly water stressed trees （75% ETc） resulted in more soluble solids and vitamin C, firmer fruit, and improved sugar：acid ratio and fruit color compared to the 100% ETo treatment. Overall, trees deficit irrigated at 75% ETc maintained yield while improving fruit quality and using less water.展开更多
文摘为提高中国三大灌区(都江堰灌区、河套灌区和淠史杭灌区)参考作物蒸散量(reference crop evapotranspiration,ET_0)温度法的计算精度,选取8个代表性站点1961-2014年逐日气象资料,采用Irmark-Allen(IA)、Hargreaves and Samani(HS)、Turc(Tur)、Mc Cloud(MC)、Schendel(Sch)、Trajkovic(Tra)、Droogres and Allen-1(DA-1)和Droogres and Allen-2(DA-2)共8种温度法计算ET_0,以FAO-56Penman-Monteith(PM)法计算结果为标准,基于各方法计算的ET0日值线性回归方程(y=kx+b),分别在都江堰灌区选取IA法和Tra法,河套灌区选取HS法、DA-1法和DA-2法,淠史杭灌区选取IA法、HS法、DA-1法和DA-2法,引入调差参数对模型进行修订,利用均方根误差(RMSE)、平均相对误差(MRE)和Nash-Sutcliffe系数(NS)对其适应性进行评价。结果表明:都江堰灌区和淠史杭灌区所选模型修订后计算精度均有明显提高,河套灌区提高不明显;都江堰灌区IA修订模型(IA-Du法)在该灌区计算精度最高,其日值、旬值的RMSE、MRE和NS分别为0.318mm·d^(-1)、0.120和0.923,0.201mm·d^(-1)、0.093和0.959,且在不同月份均有较高计算精度;河套灌区计算精度最高模型为HS法,其日值、旬值的RMSE、MRE和NS分别为0.898mm·d^(-1)、0.326和0.785,0.547mm·d^(-1)、0.223和0.904,且在1-5月和10-12月具有较高计算精度;淠史杭灌区IA修订模型(IA-Pi法)在该灌区计算精度最高,其日值、旬值的RMSE、MRE和NS分别为0.534mm·d^(-1)、0.195和0.861,0.390mm·d^(-1)、0.167和0.896,且在不同月份均具有较高计算精度。因此,推荐IA-Du法、HS法和IA-Pi法分别作为都江堰灌区、河套灌区和淠史杭灌区计算参考作物蒸散量的方法。
基金the financial support from the National High-Tech R&D Program,China(863 Program,2011AA100504)the National Natural Science Foundation of China(51579211)+3 种基金the Key Research Project of Universities in Henan Province,China(16A416005)the 111 Project of the Chinese Education Ministry(B12007)the Initial Fund for Doctoral Reserch of Henan University of Science and Technology,China(13480016)the China Scholarship Council and USDA Agricultural Experiment Station CRIS Project(01129)
文摘We conducted a two-year study of deficit irrigation impact on peach yield and quality in semi-arid northwest China. Over two years, four-year-old peach trees were irrigated at 100, 75, 50 and 25% of peach evapotranspiration （ETc）, here, ETc= Coefficient （Kc）×Local reference evapotranspiration （ET0）. During the April-July fruit production season we measured root zone soil water depletion, sap flow velocity, net photosynthetic rate （Pn）, transpiration rate （Tr）, stomatal conductance （Gs）, water use efficiency （WUE=Pn/Tr）, fruit quality, and yield under a mobile rain-out shelter. Increased soil water depletion reasonably mirrored decreasing irrigation rates both years, causing progressively greater water stress. Progressive water stress lowered Gs, which in turn translated into lower T as measured by sap flow. However, mild deficit irrigation （75% ETc） constricted T more than Pn. Pn was not different between 100 and 75% ETc treatments in both years, and it decreased only 5-8% in June with higher temperature than that in May with cooler temperature. Concurrently under 75% ETc treatment, was reduced, and WUE was up to 13% higher than that under 100% ETc treatment. While total fruit yield was not different under the two treatments, because 75% ETc treatment had fewer but larger fruit than 100% ETc trees, suggesting mild water stress thinned fruit load. By contrast, sharply decreased T and Pn of the driest treatments （50 and 25% ETo） increased WUE, but less carbon uptake impacted total fruit yield, resulting 13 and 33% lower yield compared to that of 100% ETc treatment. Irrigation rates affected fruit quality, particularly between the 100 and 75% ETc trees. Fewer but larger fruit in the mildly water stressed trees （75% ETc） resulted in more soluble solids and vitamin C, firmer fruit, and improved sugar：acid ratio and fruit color compared to the 100% ETo treatment. Overall, trees deficit irrigated at 75% ETc maintained yield while improving fruit quality and using less water.
