The result showed that the diurnal variation of temperature, irradiation intensity, net radiation as a curve in cotton canopy of two irrigation ways.
结果表明，在两种灌溉方式下棉花冠层内的温度、光照强度和净辐射日变化曲线均呈单峰线；
2
Based on the data collected in this study, netirrigation water requirement of main crop in china has been gotten.
根据收集到的资料，计算得出全国主要作物的净灌溉需水量。
3
After these, this paper analyses the features of irrigation benefits, and calculates the average benefit of every scheme with simulated method, using Economic Net Present Value.