Study On The Optimization Of Water-saving Cropping Structure In Weibei Dry-land

As the population increases,the situation of water resource crisis and environmental deterioration faced by human beings become more and more serious.The water resource crisis becomes seriously hinderers to the sustainable development of agricultural production.It isn't effective that the agriculture development rely on consuming water resource and the expend of irrigation area.To set up a cropping system that is adaptable to the rainfall resources and favorable to the raise of water use efficiency and ratio is the basic prerequisite to realize sustainable development of agriculture in dry-land regions.The main achievements of the research are as follows:1.On the basis of climate data of Weibei dry-land in past 50 years(1957～2007),the rainfall distribution law with time and space and features was analyses.It was showed that the average amount of rainfall every ten years is reducing.It was lesser 21.1 mm in 2000s than that in 1980s. The average amount of rainfall in the past 50 years was 585.42mm.2.The overall and systematic investigation of time-sequence relationship between growth of different crops and rainfall distribution was did in this paper.And water utilization condition of dry-land crops was researched.The results showed that from the viewpoint of water adaptability, the autumn crops were better than the summer crops.The study results show that in line with productive potential the crops can be put in order as:alfalfa＞corn＞potato＞winter wheat＞millet and panic3.In order to attain the maximum comprehensive benefits of economic,society and ecology, the thesis established a multi-objective fuzzy optimization model of water-saving cropping structure.4.Conclude the optimized project in the year of 2010,2015 and 2020.According to the project,compared with 2007,11%,19%,24%decreased in crops planting area respectively;7%, 12%,17%increased in economic crops planting area;8%raised in fodder-crops planting area.And the utilization efficiency of rainfall ascend from 6.86 kg/mm·hm~2 in 2007 to 14.08 kg/mm·hm~2 in 2020.