Study On The Soil Function Evaluation And Regionalization Of Farmland In Heilongjiang Province

In this study,the research framework of " Cultivated land soil function evaluation—Restrictive evaluation of soil function—Cultivated land use zoning and optimization " was established.Taking Heilongjiang Province as the research area,the farmland soil function was divided into Primary Productivity,Nutrient cycling and provision,Habitat for functional and intrinsic biodiversity,Water regulation and purification,Carbon sequestration and regulation,integrating soil,climate and terrain,land use,social economy,remote sensing and other multi-source,multi-scale data,taking 1km × 1km grid as the evaluation unit to carry out refined evaluation of the cultivated land and soil function in 2018 in Heilongjiang Province,using multi factor comprehensive evaluation,geographical detector,Spearman rank correlation and other analysis methods,combined with mathematical statistics methods,spatial analysis technology,etc.,to put forward the division scheme and optimization of cultivated land use function The main conclusions are as follows:(1)This paper expounds the connotation and characteristics of farmland soil function,theoretically analyzes the research framework of farmland soil function evaluation and zoning,follows the logic of "farmland soil function evaluation-soil function influencing factor analysis and restrictive evaluation-zoning and optimization",constructs the overall research framework of farmland soil function evaluation and zoning,and establishes farmland soil function evaluation and zoning The evaluation method system of soil function limitation,and the research idea of farmland utilization function division and optimization.(2)From the single function evaluation results,the primary productivity function,nutrient cycling and provision function,habitat for functional and intrinsic biodiversity function and carbon sequestration and climate regulation function of paddy field and dry land are roughly the same,mainly showing a decreasing spatial distribution law from northeast to southwest;water purification and regulation function is mainly in the first level area,mainly distributed in the north of Ning ‘an City,the east of Shuangcheng City The middle of Boli County,the west of Longjiang County and the northeast of Fuyu County.The primary productivity function,nutrient cycling and provision function of paddy field and dry land are almost the same;the habitat for functional and intrinsic biodiversity function,water purification and regulation function,and carbon sequestration and climate regulation function of paddy field are better than those of dry land,mainly because the water content and organic carbon content of soil are important factors affecting the function of these three functions,but compared with dry land soil,The water content of paddy soil is more stable,the organic carbon content is higher,and the function of paddy soil is higher under the comprehensive action.From the results of spatial distribution of soil function comprehensive evaluation,the study area shows the distribution law of high grade in the northeast and low grade in the southwest.The area of the second-grade area is the main area,accounting for 46.59% of the total area of cultivated land in the study area.The main reason of forming the spatial distribution pattern is the comprehensive effect of climate,topography,soil type,soil attribute and other factors.(3)Based on the results of soil function evaluation,the supply-demand matrix of soil function is constructed,and the supply-demand ratio of soil function is calculated.From the perspective of spatial distribution,the supply capacity of soil functions in the southwest of the study area is weak,which can not meet the demand of human society for soil functions.On the contrary,the supply capacity of soil functions in the northeast of the study area is strong and in surplus.The main reason for this spatial differentiation is that the northeast part of the study area has uniform water and heat,flat terrain,a large area of black soil,meadow soil and other soil types with deep soil layers and sufficient nutrients.The soil has strong capacity of water and fertilizer conservation,which is conducive to the growth of animals and plants.In the southwest of China,the wind is strong and the precipitation is little,the problem of soil desertification is prominent,the soil types are mainly aeolian sand soil and saline alkali soil,the soil is strong in alkalinity and poor in water and fertilizer conservation.(4)According to the results of the geographical detector,the main factors affecting the soil function of cultivated land are slope,erosion and salinization sensitivity.The natural environment and ecological security have a more significant impact on the function of cultivated land.On the basis of the results of geographical detector,a multi factor comprehensive evaluation model is built to evaluate the soil function limitation of cultivated land in Heilongjiang Province.From the single factor evaluation results,the natural environment and ecological security are mainly in the second level area,followed by the first level area,the third level area of natural environment is mainly affected by accumulated temperature and precipitation,and the third level area of ecological environment is mainly restricted by salinization sensitivity.The social and economic restrictions are relatively strong in general,with the area of the third level area as the main area,accounting for 39.40% of the cultivated land in the province.From the comprehensive restrictive evaluation results,most of the areas in the whole study area belong to the upper middle level,the second level area is the most,followed by the first level,the third level area is mainly distributed in the north,southwest and northeast of the study area.(5)Based on the above analysis results,combined with the actual situation of Heilongjiang Province,the cultivated land in the whole province is divided into four areas: grain supply area,ecological agriculture area,balanced development area and weak functional,and the corresponding cultivated land management mode is put forward according to the regional restrictions.The grain supply area should pay attention to improving the production efficiency of agriculture to ensure the continuous high and stable yield of grain;the balanced development area should highlight the regional functional advantages and promote the comprehensive utilization of cultivated land space;the ecological agriculture area should pay attention to the construction of green agricultural production base,which can develop sightseeing agriculture according to the terrain characteristics;the weak functional area should focus on the improvement of soil desertification and salinization to improve the cultivated land soil Conditions are the key to ensure the sustainable use of arable land.The study can provide a theoretical basis for the evaluation of cultivated land soil function,the optimization of cultivated land pattern and the improvement of cultivated land use management mode at the provincial level,and is of great significance for the sustainable utilization of cultivated land resources and the improvement of comprehensive benefits.