Study On Optimization Of Water-saving Crop Planting Structure In Dali County Based On Uncertainty

As a large agricultural country,the biggest constraint of China is the water shortage,mainly reflected in the imbalance between supply and demand,furthermore unreasonable exploitation and utilization,which caused the decline of groundwater level and the deterioration of ecological environment in part of areas.Therefore,there is a meaningful reason to study the utilization of water resources,planting structure optimization is an effective non-engineering method for optimal allocation of water resources.On the basis of the above situation,this paper takes the main crops planted in Dali County as the research object,and the agricultural economic benefit and the maximum utilization ratio of green water as the objective function,then established the crop planting structure optimization model under the condition of local resources supply fully guaranteed.The model was solved by genetic algorithm that combined with Monte Carlo simulation,which is used for the random variables simulation for the reason of uncertainty of some factors in the model.Finally,the optimized scheme was obtained in this way with 2013 a,then forecasted the planting structure with 2020 a as the planning year.The main conclusions in this paper are as follows:(1)The total planting area of Dali County has a decreasing trend over the years,and goes into steadily in recent years.The structure of crop planting is unstable and fluctuating;the structure of crop water usage has changed greatly over the years,and the information entropy has been increasing,the system is unstable and the degree of equilibrium is not high.(2)A planting structure optimization model was established to optimize the crop planting structure,and the optimization results show that the planting area of wheat and corn has a slightincrease,peanuts,cotton,rape and vegetables were all reduced instead,the fruit trees has a large increased.With optimization,the economic benefit would be [3.469×109,3.656×109] yuan,which could increased by 2.70×108 yuan,the irrigation water demand was 2.26×108m3 and reduced by6.0×106m3,the utilization rate of green water was increased by 3.44 percent.(3)The sensitivity analysis of variables in the model shows that the changes of fruit trees have the greatest influence on economic and water saving objectives among several crop variables,vegetables are the second,besides,fruit trees,wheat and corn are more sensitive to water-saving goals.The results show that the optimization of agricultural planting structure is one of the most important means to improve the agricultural water use efficiency and ensure the agricultural income.It has a certain potential in alleviating the water resources shortage.