一年两熟制下旱地土壤水分动态的初步研究

A Preliminary Study of Soil Moisture Dynamic On Dryland

本文研究了土壤水分的季节变化和垂直变化。土壤季节变化可划为4个时期:秋季缓慢蒸腾消耗期(9-11月)、冬季冻结水分相对稳定期(11-翌年3月)、春季初夏返浆蒸发水分强烈消耗期(4-6月)、雨季雨水下淋水分恢复期。土壤水分垂直变化划分为3个层位即活跃层(0-20cm)、次活跃层(20-60cm)、深墒较穗层(60cm以下)。在没有补充灌溉条件下,自然降水直接影响着土壤水分状况。5月至6月份是全年最干旱时期,表层0-20cm土壤含水量为5.50％,0-100cm平均土壤含水量为22.16％,土壤干旱落后于大气干旱,冬春季土壤贮水量与同期降水量关系不大,而夏秋季降水量与1m土层贮水量有一定相关关系,降水对土壤表层及上层影响较小,而对深层土壤水分影响较大。

This paper deals with the laws of seasonal and vertical changes of soil moisture in the current planting system. Four distinct stages of soil water regime are recognized, the slow lossing of soil moisture from Sep. to Nov.; the stable of soil moisture in the freezing time; the rapid lossing stage of soil moisture from April to Ju'ne and the storing stage of soil moisture from June to Aug..Vertical change of soil moisture in 0-100cm can be divided into three layers: the active layer(0-20cm), the secondary active layer (20-60)and the relative stable layer with good moisture(60-100).