黄土长武塬区农田生态系统水量平衡研究

摘要

以黄土高原沟壑区的典型代表长武塬为研究区,选取玉米农田生态系统为研究对象,通过测定冠层截留量、土壤含水量和估算蒸散量等水量平衡的各个组分,分析土壤水分、蒸散与降水量的关系,评估玉米农田的水量平衡状况,正确认识和评价黄土塬区农地系统的生态水文效应.结果表明:2012-2014年研究区降雨量均低于多年降雨平均值,降水距平均百分率为-17.7%、-10%和-5%,属于正常年,雨季降雨量所占比例均高于多年平均雨季降雨量所占比例;作物生长期农田生态系统平衡项均较大,说明研究样地水分收支闭合程度较低,尽管雨季降雨能够使土壤水分得到暂时的补充,但水量平衡状况较差,原因可能在于研究时间尺度的局限性、大暴雨的出现以及测量误差的产生.%The Changwu tableland in the Loess Plateau, China was selected as the study area to analyze the water balance of farmlands (corn) through measuring and evaluating various components of water budget such ascanopy interception, soil water content and evapotraspiration.The purpose is to understand and evaluate the eco-hydrological effect of farmlands in the Loess tableland.The results showed that the annual precipitation during the years of 2012-2014 was lower than that of long-time average annual value, and the precipitation in the rainfall reason was higher than that of long-time average annual value.The closure error of water balance in the farmlands was high, indicating there was not balance of water budget, and the reasons would be time scale, rainstorm event and measurement error.The results would provide theoretical support for the restructuring of farmland and orchard in the Loess Plateau and the sustainable use of limited soil water resources.