System Analysis And Dynamic Model Research On The Joint Allocation Of Cultivated Land And Ecological Land

Cultivated land is the material basis and condition for human survival and development.Ecological land is an important guarantee for maintaining ecological balance and satisfying people’s yearning for a good ecological environment and a better life.The increase of population and the need of social and economic development lead to the increasing tightening of cultivated land resources.Irrational cultivation is an important reason for the degradation of cultivated land.While seriously affecting the effective supply of food,it also brings tremendous pressure to the environment.As a base of heavy industry in China,Tianjin uses sewage to irrigate farmland earlier,which makes the content of heavy metals in farmland soil exceed the standard in sewage irrigation area,and seriously threatens food security.We should scientifically promote the rotation and fallow system of polluted cultivated land and promote the restoration of cultivated land through the conversion between cultivated land and ecological land.This is of great significance for ensuring the sustainable use of land resources.The main work of this paper is as follows:Firstly,this paper makes a comparative analysis of the current economic development situation,development trend and the development and utilization of land resources in Beijing,Tianjin and Hebei.Secondly,in order to ensure food security and ecological security under the condition of the loss of arable land quality and the decrease of arable land quantity,taking Tianjin as an example,this paper uses the method of system dynamics to analyze the relationship among Tianjin’s social,economic,environmental and resource systems.The feedback relationship and system dynamics model(CLERSD)of cultivated land ecological restoration system were constructed and the reality of the model was tested.Thirdly,six scenarios of three types of green development,sustainable development and ecological restoration were set up to simulate the joint deployment of cultivated land and ecological land in Tianjin from 2016 to 2030.The research results show that in the long-term trend,reducing the use of pesticide and chemical fertilizer could increase grain yield in the green development strategy.Although increasing the use of chemical fertilizer and pesticide could increase grain yield in a short time,it would not be beneficial in the long run,and more cultivated land would need ecological restoration because of damage.In the strategy of sustainable development,increasing investment can increase grain production and promote sustainable agricultural development.Increasing sewage irrigation can better meet the demand of crop growth water in the short term,but long-term use will lead to the increase of cadmium content,which will make more arable land need to be converted to ecological land,so as to reduce the number of arable land and increase the ecological land.In the strategy of ecological restoration,planting plants with strong metal enrichment ability can make ecological land complete the restoration of damaged cultivated land in a relatively short time,and reduce the content of heavy metals in soil and increase the number of cultivated land.Finally,in agricultural production,we can better maintain food security and agricultural green sustainable development by changing the input of pesticides and fertilizers,funds,reducing sewage irrigation and ecological restoration of cultivated land.