| Through the comprehensive evaluation of water and soil resources and eco-environment in major grain producing areas,the development status of water and soil resources a nd ecoenvironment in these areas can be clarified,which is of great significance for maintaining green and sustainable agricultural development and ensuring food security.In this paper,13 major grain producing areas in China are taken as the study are a,and the DPSIR model is used to build the eco-environment index system.The original data is used to represent the static development trend of the eco-environment of water and soil resources,and the annual average growth rate is used to represent the dy namic development trend of the eco-environment of water and soil resources.The random forest model is selected to conduct a comprehensive evaluation of the eco-environment of water and soil resources in the major grain producing areas from 2005 to 2020,A nd analyze the future development trends of soil and water resources and eco-environment under different scenarios based on important indicators,and seek the optimal development scenario.The specific research content and conclusions are as follows:(1)Construction of regional evaluation index system.Based on the DPSIR model and the basic principles of index system establishment,the evaluation index system of the eco-environment of soil and water resources in the main grain producing areas is constructe d.The criterion layer of the index system consists of five parts: driving force(D),pressure(P),state(S),impact(I)and response(R).18 indicators are selected as the index layer by combining the characteristics and development status of the main gr ain-producing regions,and the evaluation criteria of each indicator are determined through literature search,which are five evaluation levels: extremely discordant,discordant,basic harmony,harmony and ideal state.(2)Comprehensive evaluation of the e co-environment of regional soil and water resources.The random forest model with fewer adjustment parameters and better adaptability to the data set is used to conduct a comprehensive evaluation of the eco-environment of soil and water resources in the study area from 2005 to 2020,and the dynamic changes of each index are represented by the average annual growth rate,and the static evaluation results represented by the example data are compared and analyzed,and the eco-environment of soil and water resources is evaluated by combining dynamic and static.The results show that the multi-year static evaluation results of the north and south regions in 2020 are 4.50 and 4.80 respectively,and the dynamic evaluation results are 4.20 and 4.05 respectively,the current situation of the north region is better but the development potential is worse,and the development of agricultural mechanization should be accelerated;the current situation of the south region is relatively worse but the development potential is better,and the prevention and control of heavy metal sources should be paid attention to,while the construction of ecological civilization should be accelerated in the north and south regions.Enhance people’s awareness and protect the importance of eco-environment.(3)Predictive analysis of the development trend of regional soil and water resources ecological environment.In order to guarantee the sustainable development of the ecological environment of soil and water resources in the main grain producing areas,firstly,the important indicators of the study area under different conditions are determined by using the random forest model.Secondly,from the development characteristics of the data itself,the development trend of important indicator s is predicted by mathematical and rational methods and set as Scenario I.Based on some national policies on the future planning of soil and water resources ecological environment,the development trends of important indicators are qualitatively designed under two conditions,high and low,as Scenario II and Scenario III,respectively.Then,the sample sets of the three scenarios were established under static and dynamic conditions,respectively.Finally,the development trend of soil and water resources ecology in the study area was obtained by random forest regression model.The results show that Scenario II is the most objective and ideal development scenario when the per capita grain yield reaches the optimal planning and the other important indicators are raised to the planning value according to the national policy,which can effectively improve the state of regional soil and water resources ecological environment and maintain a better development potential.The northern region should develop plans to increase the penetration rate of agricultural mechanization and improve the efficiency of water use,and increase urbanization investment to increase the GDP per capita. |
