| Rainfall runoff regulation is an important way to solve the problem of drought and soil erosion in the Loess Plateau. It has always been a problem that how to make full use of rainfall resources to increase crop yield, and also nowadays, it is a hot issue in the research field of the efficient utilization of water and soil resources in the loess plateau area. On the basis of analyzing the rule of runoff on the existing slope and the utilization models of rainfall runoff, by means of located field observation experiment, and through layouting various kinds of water and fertilizer coupling experiments concerning runoff regulation measures and rainfall runoff collecting supplementary irrigation for apple on the slope surface, the effect of different rainfall runoff regulation models on slope erosion, maize growth has been analyzed and the placement indices of the utilization models of supplementary irrigation with catchment rainfall for apple has been optimized. Preliminary test results are as follows:(1)The result of new soil conditioner BGA in runoff regulation shows that,Under the conditions of individual rainfall as 45.4 mm, rainfall duration as 540 min, and average rainfall intensity as 0.084 mm/min, there is no runoff yield with straw mulching and the application of water retaining agent, while three other regulation measures have the runoff coefficient in the order from small to big: equal height ridge culture planting, the application of BGA soil conditioner, general planting. Straw muching and application of water retaining agent play a great role in increasing permeation and reducing runoff, while application of BGA soil conditioner does not.(2)The result of orchard in GanSu XiFeng shows that, the index parameters of utilization model of supplementary irrigation with catchment rainfall for apple suitable to loess plateau gully region can be determined preliminarily: during the years of different rainfall guarantee rate, to collect all the runoff, the required area of runoff-collecting surface is 360～570 m2/hm2, and allocated water cellar volume is 105～110 m3/hm2, supplementary irrigation quota is 55～60 m3/hm2, supplementary irrigation time is during the germination stage and the fruit expanding process, net fertilization application reference is 0.2～0.3 kg/plant, fertilizer ratio is 1:2:2, and at the same time the ratio of output to input of this model is 1.41, and also the surface runoff can be effectively decreased and further the erosion can be prevented. In the high tableland gully region of Loess Plateau,as for the tableland surface, the average annual rainfall range is 450～530 mm, the annual mean temperature is 7.5～13.5℃, as for the orchards catchment irrigation in the high tableland gully region of the loess area of high altitude with mean altitude 1500 m the high tableland model can be the reference.(3)According to the research carried out in the high slope area in Yan An and An Sai,the index parameters of utilization model of supplementary irrigation with catchment rainfall for apple suitable to loess hilly region can be determined preliminarily: during the years of different rainfall guarantee rate, to collect all the runoff, the required area of runoff-collecting surface is 270～430 m2/hm2, and allocated water cellar volume is 95～100 m3/hm2, supplementary irrigation quota is 50～55 m3/hm2, supplementary irrigation time is during the germination stage and the fruit expanding process, net fertilization application reference is 0.5～0.7 kg/plant, fertilizer ratio is 1:1:2.In the hilly and gully region of Loess Plateau, as for the slope terrace, the average annual rainfall range is 500～580 mm,when the annual mean temperature range is 8.5～13℃, this model is adopted. |
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