地下水埋深对冬麦田土壤水分及产量的影响

通过6种地下水位控制处理和对照(自然地下水位)冬小麦试验,探讨了不同地下水埋深对冬麦田土壤水分季节变化规律和垂直变化规律、地下水-土壤水界面水分转化量变化过程以及对冬麦田田间土壤水分平衡的影响。结果表明,地下水埋深对冬麦田0～60cm土壤水分动态有着明显的影响。地下水埋深越浅,麦田表层和主要根层土壤储水量季节变化越强烈,地下水对土壤水分的补给量越大,冬小麦全生育期耗水量也随着增加;土壤排水量大小与灌溉量和降雨量大小有关。地下水位埋深越深,灌溉和降水后的土壤开始排水日期越滞后;无论地下水埋深深浅,冬麦田累计地下水补给量变化规律可分为4个阶段,即稳定增长期、缓慢增长期、快速增长期和趋于稳定期;地下水埋深1.5m时冬小麦产量最高,地下水位太深或太浅产量均下降。水分利用率最高值出现在地下水埋深1.0m的处理。地下水位在1.0m以下时,水分利用效率随地下水深度加深和灌水量增加而减少。

Influence of Water Table on the Soil Water Variation and Crop Yield of Winter Wheat Field

Through a field experiment which consisted of six water table control set at 0.5m, 1.0m, 1.5m, 2.0m, 2.5m, 3.0m from soil surface and one free water table, the influence of water table on the seasonal and vertical variation law of soil water, the transformation process between groundwater and soil water, and the balance of soil water was researched in this paper. The results showed that different water table has remarkable influence on water content in 0-60cm soil layer. Soil water content varies more seriously under shallower water table, and it lead to more ground water uptake and more water use. The start day of soil drainage after irrigation or rainfall lagged under deeper water table. No matter the water table, the variation law of groundwater supply quantity can be divided to four phases ,as steadily increase phase, slowly increase phase, rapidly increase phase and tending to be steady phase. The highest crop yield occurs when water table set at 1.5m and the highest WUE (water use efficiency) occurs when water table set at 1.0m.