Optimization And Utilization Of Water Resource For High Efficient Agriculture In Suburb Region In Beijing--Case Study In Shunyi County

The conflict of water consumption between industry, agriculture and living is becoming sharp in suburbs of Beijing. Based on case study in Shunyi County, water requirement and water use efficiency of crops in the region were studied through onsite experiment and typical household survey. On the ground of analyses of the sustainability of regional water resource balance, the trend of water use in the future was projected in this paper. Water-saving cropping structure and the optimization of cropping pattern were also discussed. Main results are generalized as follows:In dry year, coupling fitness of water requirement to rainfall reaches 90% for sorghum and spring millet during crop's growth and reproductive season in Shunyi county, while 85% for peanut and soybean, 70% for spring com and cotton, 65% for alfalfa, and 55% for cropping pattern of rice followed by wheat. Compared with coupling fitness of water requirement to rainfall, crop's water requirement and irrigation requirement show the contrary trend. So autumn crops should not planted excessively because of the scarce water resources.Water use efficiency in Shunyi is comparatively 12-50% lower than national level at present for crops except rice and soybean, which means a great water-saving potential in the region according to comparison between experimental observation and estimation. For most crops, yield potential can hardly be increased. Therefore, it is necessary to enhance water-saving efficiency of cropping in the region. /Based on the trends of present cropping development and irrigation efficiency increase in the region, water supply can meet irrigation by 89% in 2010, 75% in 2020 and 70% in 2030 to crop's water requirement under normal condition. Water supply can meet irrigation by 100% in 2010, 88% in 2020 and 83% in 2030 to 85% of crop's water requirement under normal condition. The situation of water shortage in the region is more austere in dry year.In the view of regional water balance and cropping irrigation efficiency increase, optimized model for the mid-long term cropping was proposed. Practicing these pattern can guarantee water resources balance, satisfy the requirement of production, economic increase and ecological efficiency for agriculture.