土壤水分再分布特性研究进展

在干旱半干旱地区,土壤水分的再分布对生态环境、农业发展有着重要的影响,是自然界中水循环的重要过程之一,是土壤墒情的自我调节过程,是土壤水在势力梯度作用下的非饱和运动.在国内外学者多年研究工作的基础上,分别从物理角度和生物角度对土壤水分再分布的基本理论和模型进行了归纳总结.从物理角度分别以耕作措施、雨强、灌水方式、土壤初始含水率等因素对土壤水分再分布过程的影响进行了研究,并归纳了基于土壤水分特征曲线及其滞后作用、土壤水分运动通量法、土壤水分运动基本方程等的数学模型.从生物角度对土壤水分再分布的生态功能及影响因素进行了总结:研究发现土壤水分的再分布作用可以有效地调节根系层土壤水分状况、丰富群落结构,提升土壤养分、增加根层土壤微生物;植物根系在对根层水分进行调节的过程中又会因土壤水分、植物种类和土壤特性的不同而发生变化.通过对前人研究成果的总结,理清研究现状,以期为理论的进一步研究提出建设性意见.

Progress in research on soil water redistribution

Soil water redistribution has significant effects on local ecosystem and agriculture in arid and semi-arid farmlands in the Loess Plateau. In a redistribution proess, soil water moves in unsaturated soil under the potential gradient. This article reviews and summarizes theories and models in soil water redistribution achived in China and abroad from point of view of both physics and biology. It is found out that the progress is mainly affected by cultivation measures, rainfall intensity, initial moisture content and irrigation method from point of view of physics. The developed mathematical models based on soil water characteristic curve and its hysteresis, soil water flux method, and soil water motion equations etc are clarified. It is also identified that the soil water redistribution can effectively regulate soil moisture condition in root layer and enrich community structure and improve soil nutrient; but the process can be influenced by soil moisture, species and soil properties.