Analysis And Research On Ecological Carrying Capacity And Environmental Risk In The Environmental Impact Assessment Of Grassland Protection And Utilization Planning

Grassland is an important type of vegetation in China.In order to grasp the grassland resources and ecological status of the whole province,it is necessary to carry out grassland protection and utilization planning.For the planning of grassland protection construction and utilization,the planning environmental impact assessment must be carried out.At present,the ecological carrying capacity and risk assessment are still in the development stage in the planning environmental assessment.In this paper,through the research on the analysis method of ecological carrying capacity,combined with the investigation of grassland status in Sichuan Province,the comprehensive analysis method is used to analyze the comprehensive ecological carrying capacity state of the three prefectures of Sichuan Province,and the grey system model is used to simulate and predict the three indexes of fresh weight output,comprehensive vegetation coverage and livestock overload rate of the natural grassland in Sichuan Province;at the same time,through the information diffusion theory The risk of grassland fire,rodent and pest in Sichuan Province was analyzed.The conclusions are as follows:(1)The comprehensive ecological carrying capacity of each county in Aba and Ganzi Prefecture is in a state of low stability-low carrying capacity-low pressure and below.The bearing pressure index of each county is higher than the carrying capacity index,and the grassland ecosystem is relatively fragile.The ecological elasticity index of all counties in Liangshan Prefecture is higher than the bearing pressure index,and the resource bearing pressure is relatively small,but more than half of the county’s ecosystems are still in a low stability-low bearing state,and the general ecological bearing state is average.(2)The results of simulation and prediction of three indicators of fresh grass yield,comprehensive vegetation coverage,and livestock overload rate of natural grasslands in Sichuan Province show that the annual fresh grass yield and comprehensive vegetation coverage of natural grasslands are increasing year by year.The ecology has gradually improved;the trend of reduction in livestock overload rate is relatively obvious,and the grassland animal husbandry is developing in a green and sustainable direction.(3)It is calculated through the information diffusion theory model that the probability of grassland fires in Sichuan Province is 0-15 times per year(more than 0.5159);the probability of grassland fire disaster area is 250-750 hectares per year(more than 0.5334).;The probability of damage to grassland pests in the range of 2.5 to 3 million hectares is relatively large per year(more than 0.4178);the probability of the area of grassland pests to harm in grasslands is 770,000 to 830,000 ha per year(more than 0.4620).(4)It is suggested that all kinds of resources in the three prefectures should be rationally planned,utilized and developed in the grassland planning,so as to improve the ecological carrying capacity of the grassland in Sichuan Province,strengthen the management of grassland fire,rodent and insect disasters,and grassland desertification,and effectively reduce the harm of grassland risk.