Research On The Change And Zoning Of Cultivated Land Ecosystem Service Value In Qinghai Province

Cultivated land is an important natural resource to ensure food security,ecological security and sustainable development.Population growth,urban expansion and economic development have led to problems such as high-intensity cultivated land use pattern,massive loss of high-quality cultivated land,deterioration of farmland ecological environment,etc.,which have led to the decline of cultivated land ecosystem service level in the whole society,posing a threat to national food security and sustainable agricultural development.Qinghai Province has a vast territory,complex topography,poor natural endowment,many restrictive factors of cultivated land utilization and development,and great regional differences.It is typical to study the evaluation of cultivated land ecosystem service value in Qinghai Province,which is located in the alpine farming-pastoral ecotone and the typical fragile ecological environment area,but the existing cultivated land evaluation system has not yet defined the ecological value of cultivated land.In view of this,it is urgent to carry out research on the evaluation of cultivated land ecosystem service value in Qinghai Province,to make up for the deficiency of ecological value evaluation of cultivated land in ecologically fragile areas,and to explore plot-scale cultivated land zoning based on multiple attributes of quantity,quality,ecosystem service value and multiple constraints of spatial control,so as to provide scientific data support and certain reference for realizing the trinity protection of quantity,quality and ecology of cultivated land in Qinghai Province,optimization of spatial pattern of cultivated land utilization,sustainable development of agriculture and formulation of differentiated protection policies.In order to clarify the ecosystem service value of cultivated land in Qinghai Province from 2000 to 2020 and its temporal and spatial change characteristics,this paper obtained the cultivated land information of Qinghai Province in 2000,2010 and2020 through Globe Land30 images,and identified the temporal and spatial change characteristics of cultivated land from 2000 to 2020 by land use transfer matrix and landscape pattern analysis,combined with relevant data such as meteorology,soil,topography and statistics.The universal water yield model,soil conservation model and various value calculation formulas were selected to evaluate the grain yield value,carbon fixation and oxygen release value,water conservation value and soil conservation value of cultivated land in Qinghai Province in 2000,2010 and 2020,and the temporal and spatial variation characteristics and synergistic trade-off analysis of the above values were carried out.On this basis,the spatial autocorrelation and cluster analysis are used to study the cultivated land zoning based on the multi-attribute of cultivated land quantity,quality,ecosystem service value and spatial control constraints.The main conclusions are as follows:(1)Spatio-temporal changes of cultivated land in Qinghai Province: from 2000 to2020,the area of cultivated land in Qinghai Province increased first and then decreased,and the amount of cultivated land remained balanced as a whole,showing the distribution characteristics of "more east and less west" and the change characteristics of "less east and more west".As a whole,the center of gravity of cultivated land shows the characteristics of gathering in the east,shifting from southeast to northwest in space.The results of land use transfer matrix show that77.98% of cultivated land in Qinghai Province has not changed from 2000 to 2020,and the reduced cultivated land is mostly occupied by construction.Most of the newly added cultivated land comes from the development of other grasslands and unused land in the reserve resources of cultivated land in the central and western basins.Although the fragmentation of cultivated land has increased,the change is not obvious.(2)Cultivated land ecosystem service value: From 2000 to 2020,the cultivated land ecosystem service value in Qinghai Province showed a gradual upward trend,with an increase of 1.671 billion yuan,of which the increase in 2000-2010 was greater than that in 2010-2020;The order of increment of ecosystem service value is: grain production value > soil conservation value > water conservation value > carbon fixation and oxygen release value.In terms of space,the ecosystem service value of cultivated land in Qinghai Province is characterized by a decrease in scattered counties in the south and an increase in other areas,while the ecosystem service value per unit area of cultivated land is characterized by a decrease in the north and central parts and an increase in the east and south.At the same time,the spatial correlation matrix of the above values shows that all kinds of ecosystem service values show different degrees of synergistic growth relationship.(3)Cultivated land division: Through systematic cluster analysis of cultivated land quantity,quality and ecosystem service value in Qinghai Province,it is found that there are four obvious cluster types of cultivated land in Qinghai Province.On this basis,three districts and three lines in Qinghai Province are taken as the constraint conditions of spatial control,and cultivated land division in Qinghai Province is divided,including key protection areas,ecological remediation areas,quality improvement areas,land-people contradiction reconciliation areas and fallow areas,which respectively account for 42.55%,23.51%,23.34%,8.58% and 2.02% of the cultivated land area in the province.Combined with the spatial distribution and regional characteristics,the corresponding protection measures and suggestions are put forward,and the cultivated land ecological monitoring index system and dynamic monitoring model are established.