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作物产量一般与蒸发蒸腾量呈线性关系,而后者又与土壤水分密切相关,只有当土壤水分维持在某个临界值以上,才能避免减产,一般认为此临界值是PF_3。 在保证土壤水分高于临界值的条件下,欲节约灌水,就要促进降雨的有效化,使有效土层内存留尽可能多的水分,在设法利用根层下方水分的同时,减少表面迳流,土面蒸发和深层渗透。具体方法可采用滴灌、确定适当的灌水期和灌水强度、改良土壤、地面覆盖、改善耕作体系等,其中以调节灌水时期和灌水量较为适用。本研究从灌溉工程角度来探讨干旱时节约灌水量的可能性。
Crop yield generally has a linear relationship with evapotranspiration, and the latter is closely related to soil moisture. Only when soil moisture is maintained above a certain critical value can yield reduction be avoided. This critical value is generally considered to be PF_3. To ensure that the soil moisture is above the critical value, to save irrigation, it is necessary to promote the effectiveness of rainfall, the effective soil layer to retain as much water as possible, in trying to use the water under the root layer while reducing the surface flow , Soil evaporation and deep penetration. Specific methods can use drip irrigation to determine the appropriate irrigation and irrigation intensity, soil improvement, ground cover, improve farming system, etc., of which the regulation of irrigation period and irrigation is more applicable. This study explored the possibility of saving irrigation volume during drought from the perspective of irrigation engineering.