黄土高原荒坡径流生产潜力研究

STUDY ON THE PRODUCTIVITY POWER OF RUNOFF IN THE LOESS PLATEAU

运用“单株平衡法” ,测定了油松、刺槐优势木单株年耗水量。并以此作为林地水分生产力评价的依据 ,提出了“期望最低水分潜势标准”及“降雨径流期望生产力指数” ,并指出径流系数是决定径流生产力的主要因素。对黄土高原荒坡径流生产力进行了必要的理论探讨。计算求得了利用自然坡面径流 ,油松、刺槐可望成林、成材的降雨量下限均为 50 0mm ;在 4 0 0mm降水地区 ,仅能形成郁闭度为 0

The amounts of used water by single dominant trees of Pinus tabulaeformis and of Robinia pseudoacacia ,by using as the basis for evaluating the productivity power of available water of forest land,were measured by using ‘the measuring method of single\|tree water\|cycle balance’.The base amount of the available water of a forest land for stand normal growth and the productivity power index of runoff were set.The runoff coefficient is thought as a decisive factor to affect runoff productivity power.The productivity power of forest land was counted in the Loess Plateau.The results show that the minimums of annual precipitation for stand normal growth of the two species are all 500mm by collecting the runoff on nature slope.There will be only a stand with 0.3 crown densities in the area where the annual precipitation is 400 mm.