干旱缺水条件下麦田蒸散量的计算方法

A METHOD OF CALCULATING EVAPOTRANSPIRATION FROM THE FARMLAND WITH SOIL WATER DEFICIT.IN ARID AND SEMIARID AREAS

本文从试验资料出发,分析了干旱缺水条件下的麦田蒸散规律,以水量平衡方程为基础,且综合考虑影响麦田蒸散的天气条件、土壤水分状况和小麦本身的生物学特性,选用蒸发力、相对土壤有效含水量和作物的叶面积指数三因素建立了干旱缺水条件下麦田蒸散量的计算模型以及农田土壤水分变化的预测方法。

In this paper, based on the measured data in field, the regularity of evapotranspiration with droughts and soil water deficit conditions has been analysed. Based on soil water balance equation, and comprehensively consideving over the weather condition. Soil moisture state and crop's bioloyical property, we established the mathematics model for the computation of evapotranspiration from the farmlunds when soil moisture supply was restricted. This model involves three parameters, that is, the initial soil water content 60, the evaporation potential Eo and crop leaf area index LAI, and at the same time, the sensitivity of actual evapotranspiration from the farmlands to evaporation potential, the initial soil moisture content and leaf area index were also analysed. Also in this paper, two coefficients in widely-used penmen formula at present were modified by using the data measured at the radiation stations in Shanxi, Shaanxi, Gansu and Nei Mongol, etc' Finally, the error with the method presented in this paper hase been analysed, and the reliability with the model has been evaluated. The result of comparing the estimated evapotranspiration with measured evapotranspiration at the experiment plots in Shaanxi and Gansu provinces is that this method has good precisim, it can be used in the arid and semiarid areas in China.