Study On Planting Structure Adjustment In Beijing Based On Water Resources Perspective

According to the growing shortage of water resources and poses a serious threat to the sustainable development of agriculture and economic society in Beijing,Based on statistical data and survey data,the thesis studied the water use characteristics of major crops using the Penman formula,carried out the evaluation of the comprehensive benefits of the main crops using entropy values method and used a multi-objective planning method to conduct structural optimization decision-making research on crop farming.The main result is as follows:There are differences in the water ecological adaptability of different crops.The sorghum and millet that are cooked once a year are the crops with the highest ecological adaptability,followed by the summer crops,including summer corn,summer peanuts,and summer soybeans.The crop with the lowest water ecological adaptability is winter wheat.The water balance and comprehensive advantage of different crops in different regions are significantly different.The highest water use efficiency in field crops was summer corn,which was the highest at 15.04·kg·hm^-2·mm^-1 and was generally higher than other field crops planted in the same region.The most economically efficient of field crops for water use are sorghum and millet.The water use efficiency(20.65³5.39kg·hm^-2·mm^-1)and the economic efficiency of water use(61.94¹11.56yuan·hm^-2·mm^-1)in vegetables were the highest among all crops.The areas with higher cropland crop comprehensive index were Miyun,Daxing,Shunyi,and Yanqing district,and the highest areas for vegetable crops were Daxing,Tongzhou,and Shunyi district.The highest orchard's dominant index was in Pinggu district.In this study,crop water consumption,water use efficiency,yield,and economic benefits were used as comprehensive indicators in order to evaluate the crop product comprehensive advantage.The results showed that the comprehensive advantage of same crop in different area was differences.Combined the evaluation results of comprehensive benefits and the results of structural optimization,a reasonable planting structure was suggested,that is to reduce the area of summer maize,vegetables and winter wheat,in which the vegetables decreased by 15391.28 hm² and the winter wheat decreased by5258.06 hm²;fruit trees,beans,millet,sorghum and peanut should increase area,the fruit trees should be increased the area of 2944.65hm².Conclusion:The main direction of plantation adjustment in Beijing is to reduce the area of vegetables,summer corn and winter wheat,increase the area of fruit trees and beans.Winter wheat should reduce planting area in Huairou,Tongzhou district,vegetables should reduce planting area in Huairou,Changping and Yanqing district;corn should reduce planting area in Changping,Tongzhou,Mentougou,Haidian and Daxing district;fruit trees should increase planting area in Pinggu Miyun and Fangshan district,summer soybean should increase planting area in Daxing district.