Study On Optimal Allocation Of Agricultural Land Polluted By Heavy Metals Based On CA-Markov Model

At present,the agricultural land polluted by heavy metal which is closely related with people’s health has attracted more and more attention.The optimal allocation of land types taken the safe use of agricultural land which heavy metal exceeded the standard as the goal will provides a new idea for the research on the control technology of agricultural land polluted by heavy metal,which also has certain practical significance.This paper takes A city as the research area and takes general land use planning of 2005 and the second land survey of 2013 and so on as the basic data source.Firstly,according to the analysis on the influence factor of land use change this paper identify the main factors for the optimal configuration simulation.Secondly,Markov model is used to obtain a transfer matrix of land use,and amended according to the general land use planning.Then,the research products the multi-criteria evaluation map.Finally,through the CA-Markov module of the IDRISI platform the research achieve the optimal allocation of agricultural land in the study area and get the following conclusions:(1)From the perspective of the distribution area of agricultural land exceeded the standard,the serious area is mainly distributed in the southeast and the northern part of the A city;From the quantitative point of view,the area exceeded the standard of arable land is 2077.59hm2,accounting for 3.86% of the total area of arable land;The area exceed the standard of garden land is 560.19 hm2,accounting for 5.94% of the total area of the garden.(2)The optimization configuration simulation results of land use in 2020 show that arable land,water area and other land area are reduced.The total amount of cultivated land is basically stable and the land type of other land is reduced maximum.Forest land and construction land are increased,and the construction land increase greatly.(3)The land use change in the area of heavy metal exceed the standard in soil and allowed construction show that 72.63% arable land and 49.66% garden are transferred to construction land or woodland in severe heavy metal polluted area in soil,which prove that the model can better achieve the goal of the safe utilization of the farmland polluted by heavy metal.Construction area in allowed construction zone is rapidly expanding and water area for ecosystem services increase.The cultivated land,woodland,garden land and other land area are reduced,so the allocation results can provide reference for the new construction land of A city.(4)The land use change of land remediation area results show that arable land area increases by 1705.74 hm2,which is mainly supplemented by the land type of other.This area has well suitability of cultivated land as the mainly land type of reclamation.(5)At the end of this paper,according to the simulation results the study area is divided into four types,which provide a reference for soil heavy metal control policy of agricultural land.How to adjust the land use and which area should be changed in heavy metal exceeded agricultural land have been solved by CA-Markov.The results provide support for the establishment of local control policies.