| A study on the design of runoff-collecting system was carried out for auto-flowing drip irrigation under film as well as its ecological benefit in slope land of the Loess Plateau.Utilizing this system invented by the author, the rainfall could be collected in rainy days. On the other hand, in dry season, natural height difference could induce rainfall to drip into collecting bag for auto-flowing drip irrigation under film by dripping tube.These measures raised effectively rainfall use efficiency, solved the difficulty in irrigation due to cracked landform and scattered trench on slope land area.The results of several-year trials on drought-resistant forestation and water-saving trial on crops showed that water-collecting drip irrigation system could enhance obviously the soil moisture in 20～70 cm soil layer as well as the survival rate of Acacia, Chinesepine and Jujube to 57.0%, 77.8% and 69.4%, which were 97.7%, 91.4% and 90.5% respectively higher than those in hole irrigation.This technique integrating film mulching under young trees could increase the caulis diameter of Acacia, Chinesepine and Jujube by 26.9%, 55.2%and 49.6% as well as crown cast area by 90.9%, 74.2% and 51.8% in the second year after planting.In the same time, runoff and erosion modulus of soil in treatment plot were decreased by 38.3% and 102.7% respectively compared with the control under 387mm rainfall.Based on these better benefits for ecology and society, it is a better technique with less input, high benefit and simple operation, which could be used widely on crash mountain area and poor place in the hilly area of the Loess Plateau. |