Research On Optimization Of Agricultural Planting Structure In Yulin Based On Efficient Utilization Of Water Resources

Yulin is located in the inland area of northwest China.It is a typical temperate semi-arid continental monsoon climate.The proportion of agricultural water is still as high as 60%.With the shortage of water resources,it begins to occupy life and ecological water.Therefore,under the premise of ensuring water resources-ecological sustainability,appropriately reducing agricultural water consumption has become an option to alleviate water resources and ecological deterioration in the region.Planting structure adjustment,as an important measure for water saving in agriculture,is of great significance for improving food security and ensuring sustainable use of water resources.This paper takes Yulin City as the research area,evaluates the water resources carrying capacity of Yulin City in response to the shortage of water resources in Yulin City,and obtains the water use threshold of planting industry through the optimized water distribution model of each water department in Yulin City,thus constructing a two-layer planning model.Optimize the crop planting structure and evaluate different options.The main contents and conclusions of this paper are as follows:(1)Water resources optimization in the water sector of Yulin City.Forecasting the water demand and water availability under the 50%rainfall frequency of Yulin.Based on the analysis of supply and demand water,the optimal allocation model of water resources with social,economic and ecological environment is constructed,and the optimization results of comprehensive social,economic and ecological benefits are obtained.According to the analysis,the water shortage rates were 3.2%and 4.1%.Based on the analysis of supply and demand water,the optimal allocation model of water resources with social,economic and ecological environmental benefits is constructed,and the optimization results of comprehensive social,economic and ecological benefits are obtained.The results show that the water shortage rates in 2020 and 2030 are 3.3%and 5.9%respectively;the output values are 0.70 trillion and 1.39 trillion respectively;the COD emissions are 30500 tons and 31700tons respectively.Based on the optimal allocation of water resources,it can meet the reasonable demand for water in various sectors in the case of increasingly tight water resources.(2)Evaluation of agricultural water resources carrying capacity.This paper uses the factor analysis legal authority to determine the weight of the index,constructs a fuzzy comprehensive evaluation model,evaluates the agricultural water resources carrying capacity of Yulin from 2011 to 2015,and finds that the overall water resources carrying capacity shows a downward trend,so the development of water-saving irrigation technology.At the same time,we must pay attention to adjusting the planting structure so that agricultural water resources can be continuously utilized.(3)Planting structure optimization.In this paper,the crops are mainly divided into eight types,and in the case of planting water distribution constraints,the two-layer optimization model of the planting structure of Yulin City with the lowest water consumption as the objective function and the lower layer with the maximum economic benefit as the objective function is constructed.By solving the model,the minimum overall satisfaction reached 0.65and 0.69,respectively,and eight crop planting structures were obtained.Compared with the current year,the double-layer planning optimization results in an increase of 5.68 million m~3of water consumption,an increase of 518 million yuan in economic benefits,and an increase of 0.74 yuan/m~3 in water consumption per unit.In 2030,the water consumption increased by23.75 million m~3.The efficiency increased by 4836.2 billion yuan,and the water use efficiency of single water increased by 0.87 yuan/m~3.It can be seen that the optimized agricultural planting structure will be of great help to Yulin in the future to improve economic efficiency and water potential.(4)Evaluation of different planting structure schemes.The evaluation index system of planting water efficiency in Yulin City was constructed.The projection pursuit model and principal component analysis method based on particle swarm optimization algorithm were used to evaluate the planting structure of different schemes.The results show that the bilevel planning result is better than the single layer planning result.It is better than the current year's planting structure scheme,which proves that the optimization result of planting structure is reasonable,and has guiding significance for the adjustment of planting structure in Yulin in the future.