晋东南地区旱地农田土壤水分状况及水分循环特征

 根据农田土壤水分的定位观测资料，应用水分平衡法研究了晋东南地区主要作物对土壤水分的利用和农田土壤水分循环的特征。结果表明，该区农田土壤水分常处于亏缺状态，亏缺量比裸地多，土壤干旱层加深。作物对土壤水分的利用能力、收获时土壤有效水分剩余量因作物而异。冬小麦对土壤水分的利用量较多，用水层较深。春玉米、春谷子利用量较少，用水层也较浅。作物收获时，农田土壤中还有较多的有效水分未被利用，说明旱地土壤水分资源尚有一定的生产潜力，有待进一步开发。

SOIL MOISTURE STATE AND CYCLE CHARACTERS OF DRYLAND FIELD IN SOUTHEAST OF SHANXI PROVINCE

According to the observed soil moisture information from the place located in southeast areas of Shanxi Province, and water balance methoa, we have studied the physical characters of soil moisture, the influence of crop to soil moisture, and field moisture cycle characters, The results suggest that the soil water deficit often exists in fields of the areas. From May to June, soil water deficit of bare-laud rises to the top of 232.8mm, and the bottom of 66.6mm appears during the period from August to September. By comparison, due to the influence of crop transpiration, both soil water deficit and soil dry layer of cultivated land are 15.1-40.4mm more and 20-70cm deeper respecsively than those of bare-land. Crops mainly planted in this area have less utilization ability to soil water. The water utilization ability of winter wheat can be the biggest of 26.2%-30.6%, and the depth of soil water utilization can deepen over 200cm soil layer. Spring corn and millet can only consume the soil water with the maximum ability and deepest layer of 13.4% and 0-50cm or 0-100cm respectively. After crop reaped, over 41% of available soil water in fields has not been used. So, increasing the soil water storage and improving the utilization ability of crops to soil water by efficient agrotechniques are one of the ways to increase the productivity in dryland farming.