坡地土壤水分动态及耗水规律研究

8年长期坡耕地土壤水分研究表明:裸地2m土层水分季节性变化呈倒S型；40～100cm内土层水分对作物供水极为重要；在降水量为500mm左右的黄土丘陵沟壑区，降水能完全满足坡耕地作物生长发育；在降雨因素不成为限制作物生长发育主要因素时，水平沟耕作可以有效地控制地表蒸发，降低作物耗水量；人工草地耗水强度趋势为:沙打旺>草木樨>紫花苜蓿>红豆草>柠条（二年生）；3年生人工草地主要利用50～200cm土层水分，8年生人工草地利用150～400cm土层水分，且8年生人工草地土壤水分恢复维艰。

Study on Soil Moisture Dynamic and Water-Consuming Law in Slop-Land

The moisture research with 8 years long-term experiments in slop-land shows: the moisture seasonal dynamic change of 0-200cm layer appears the S type; the 40-100cm layer moisture is very important to supplying water for crops; in loess hilly and gully region with about 500mm rainfall, rainfall meets the demands of crops completely; while rainfall is not a factor-limied for crop growth, the contour-level tillage controls soil water evaporation and decreases crop consuming water; the water-consuming tendency sequence of artificial grassland is as follows;Astrasalus adsurgens, Melilotus albus, Medicago satvia, Caragana korshimskii Onobrychis voiciaefolia; 3-year growth artificial grass mainly uses 50-200cm layer water, 8-year growth artificial grassland mainly uses 150-400cm layer water and its recoves is extremely difficult.