黄土丘陵沟壑区三种不同植被土壤水分动态及蒸散耗水规律研究

Study on Soil Water Dynamic and the Evapotranspiration of Three Different Vegetation in the Loess Hilly and Gully Region

通过连续5a定点观测流域土壤水分、气象要素等资料,利用水量供耗平衡原理,分析了该区域3种不同植被类型阶段储水量、耗水量和耗水规律。结果表明:天然次生林年耗水量最少,为487.8mm,玉米次之,为519.65mm;苹果最大,为540.7mm;从不同类型土壤储水量分析表明:在阴坡生长的天然次生林处于充分供水状态,年耗水量稳定在500mm左右;而玉米和苹果树全生育期内大部分月份都处在土壤水分亏缺状态,耗水量年变差较大,其年最大耗水量之差分别达240mm和140.7mm,当作物在土壤水分亏缺状态下生长时耗水量较小;年耗水量与当年降雨量关系不显著,而与降雨时间分布较为密切。

The located observation on soil moisture dynamics and analysis the characteristics of water consumption rhythm under three kinds of vegetations in five years show that annual water consumption of nature forestry, maize and apple tree are 487.8 mm, 519.65 mm and 540.7 mm respectively. Analyzing the water accumulating capacity under three kinds of vegetation showed that the nature forestry of shaded hillside grew in the condition of sufficient soil moisture and every annual water requirement is steady with about 500 ram. Apple tree and maize grew in the condition of shortage soil moisture in the almost every month, which difference of annual water requirement is very large, the variation of water accumulating capacity the nature forestry and maize are 240 mm and 140. 7 mm respectively. The crop growing of shortage soil moisture, the annual water consumption is small. The relationship between annual water consumption and rainfall is not significant. But the relationship between annual water consumption and rainfall distribution is closer.