Transformation of rainfall into runoff over an area is a very complex process which exhibits both temporal and spatial variability;runoff in a defined area can be affected by factors such as topography, vegetation, ra...Transformation of rainfall into runoff over an area is a very complex process which exhibits both temporal and spatial variability;runoff in a defined area can be affected by factors such as topography, vegetation, rainfall characteristics and soil properties. This study was conducted to develop an empirical model using the rainfall characteristics and soil properties for predicting runoff from dry-farming lands in a semi-arid agricultural area in Hashtroud, Northwest Iran. Runoff plots(1.83 m × 22.1 m) in triplicate were installed in thirty-six sloped dry-farming lands in the study area. Runoff under natural rainfalls was measured in each plot during a2-year period. The results showed that runoff for 41 runoff-producing rainstorm events with duration longer than 30 min was largely associated with a rainfall index obtained by multiplying the positive square root of rainfall depth(h0.5) by the logarithm of the maximum 30-minute intensity(LogI30)(R2= 0.81). Runoff significantly varied among the plots(P < 0.001), which was considerably related to the effective soil properties(R2= 0.74), i.e., soil permeability(Per) and aggregate stability(AS). A multiple linear regression model was developed between runoff and the rainfall index(h0.5logI30) and the effective soil properties(AS and Per). Evaluation of the model using 34 runoff-producing rainstorm events that occurred during the next two years resulted in high values of the efficiency coefficient and R2(0.88 and 0.91, respectively), which revealed that the model developed in this study could be used in predicting runoff from the dry-farming lands in the semi-arid regions.展开更多
在黄土高原半干旱雨养农业区薯麦轮作田地建立气象部门首家FACE系统(Free Air CO2 En-richment),即CO2浓度的控制和监测系统平台,由中国气象局兰州干旱气象研究所建在定西半干旱生态环境与试验基地。该平台由CO2气体供应装置、控制系统...在黄土高原半干旱雨养农业区薯麦轮作田地建立气象部门首家FACE系统(Free Air CO2 En-richment),即CO2浓度的控制和监测系统平台,由中国气象局兰州干旱气象研究所建在定西半干旱生态环境与试验基地。该平台由CO2气体供应装置、控制系统、释放系统3大部分组成,它是利用计算机网络系统对平台的CO2浓度进行监测控制,根据作物冠层高度的CO2浓度、风向、风速、昼夜的变化调节CO2气体的释放速度及方向,实现FACE圈的CO2浓度高于周围大气CO2浓度某一数值。该平台旨在研究雨养农业区CO2浓度升高及其与温度、水分、养分等偶合对农作物生长过程、生理生态特征、生物量、产量等的影响,为该地区适应未来不同气候变化情景提供科学依据。展开更多
文摘Transformation of rainfall into runoff over an area is a very complex process which exhibits both temporal and spatial variability;runoff in a defined area can be affected by factors such as topography, vegetation, rainfall characteristics and soil properties. This study was conducted to develop an empirical model using the rainfall characteristics and soil properties for predicting runoff from dry-farming lands in a semi-arid agricultural area in Hashtroud, Northwest Iran. Runoff plots(1.83 m × 22.1 m) in triplicate were installed in thirty-six sloped dry-farming lands in the study area. Runoff under natural rainfalls was measured in each plot during a2-year period. The results showed that runoff for 41 runoff-producing rainstorm events with duration longer than 30 min was largely associated with a rainfall index obtained by multiplying the positive square root of rainfall depth(h0.5) by the logarithm of the maximum 30-minute intensity(LogI30)(R2= 0.81). Runoff significantly varied among the plots(P < 0.001), which was considerably related to the effective soil properties(R2= 0.74), i.e., soil permeability(Per) and aggregate stability(AS). A multiple linear regression model was developed between runoff and the rainfall index(h0.5logI30) and the effective soil properties(AS and Per). Evaluation of the model using 34 runoff-producing rainstorm events that occurred during the next two years resulted in high values of the efficiency coefficient and R2(0.88 and 0.91, respectively), which revealed that the model developed in this study could be used in predicting runoff from the dry-farming lands in the semi-arid regions.
文摘在黄土高原半干旱雨养农业区薯麦轮作田地建立气象部门首家FACE系统(Free Air CO2 En-richment),即CO2浓度的控制和监测系统平台,由中国气象局兰州干旱气象研究所建在定西半干旱生态环境与试验基地。该平台由CO2气体供应装置、控制系统、释放系统3大部分组成,它是利用计算机网络系统对平台的CO2浓度进行监测控制,根据作物冠层高度的CO2浓度、风向、风速、昼夜的变化调节CO2气体的释放速度及方向,实现FACE圈的CO2浓度高于周围大气CO2浓度某一数值。该平台旨在研究雨养农业区CO2浓度升高及其与温度、水分、养分等偶合对农作物生长过程、生理生态特征、生物量、产量等的影响,为该地区适应未来不同气候变化情景提供科学依据。
