| China has a large arable land and the fourth largest arable land in the world,but China has a large population with 1.4 billion people,accounting for 18%of the global population.The per capita arable land area is only one-third of the global average,thus ensuring sufficient food production.It has always been the top priority of our development.At the same time,the appropriation of cultivated land has inevitably occurred in the construction of cities such as land planning in China.Therefore,the evaluation of cultivated land quality is an extremely effective measure to ensure food security and the effective use of cultivated land resources.Sustainable development is extremely important.In this paper,Anqing City is used as a research area.In combination with soil sampling point data,vector graphics,and text data in 2019,the Anqing City was used to analyze the quality of cultivated land in Anqing City.Levels.The evaluation is mainly based on ArcGIS software,county-level cultivated land resource management information system,and MATLAB as auxiliary software.The main conclusions are as follows:(1)The total area of cultivated land in Anqing City in 2019 is 378494.05 hectares.The average cultivated land quality grade is 4.92,and the overall level is medium.The high-grade cultivated land(first to third grade)mainly distributed in the area along the Yangtze River.Most of these areas are plains,and only a few are hills,basins and mountains.The soil type is mainly moisture soil and paddy soil.The content of main nutrient elements in the high-grade cultivated land is relatively high.The irrigation capacity and drainage capacity are mainly fully satisfied and satisfied.The texture of the arable layer is mostly middle soil,and the texture configuration is mostly sponge type.This part of the region has excellent geological characteristics,good soil health,and basic barrier-free factors.It is the main crop high-yield area in Anqing.The medium-grade cultivated land(fourth to sixth grade)mainly distributed in the central hilly area,and are distributed in the plains and mountains.The terrain has some ups and downs.The content of main nutrients in this area is relatively moderate,and the soil type is mainly paddy soil.And the drainage capacity is mostly satisfied and basically satisfied.The texture of the arable layer is mainly heavy soil and middle soil,the texture configuration is mainly sponge type and upper loose and tight type,and the crop yield is medium.The low-grade cultivated land(seventh to tenth grade)mainly distributed in the Dabie Mountains.This part of the area is dominated by hills and mountains.The irrigation capacity and drainage capacity are basically satisfied.The texture configuration is poor.The thin layer type is mainly used.The cultivated layer texture is mainly It is sandy soil,with relatively low levels of main nutrient elements,other cultivated land indicators are poor,and crop yields are low.The first-class land area is 5004.6 hectares,accounting for 1.32%of the total cultivated land area,mainly distributed in Wangjiang County;the second-class land area is 26194.48 hectares,accounting for 6.92%of the total cultivated land area,accounting for the largest proportion in Wangjiang County;third-class The land area is 50588.38 hectares,accounting for 13.37%of the total area,with the most distribution in Huaining County;the fourth-grade land area is 112708.2 hectares,accounting for 29.78%of the total cultivated land area,mainly located in Susong County;the fifth-grade land area is 61050.28 hectares,accounting for 16.13%of the total area of cultivated land is also the most distributed in Susong County;the area of the sixth grade is 42802.38 hectares,accounting for 11.31%of the total area of cultivated land,and the most widely distributed in Huaining County;the area of the seventh grade is 36799.42 hectares,accounting for the total area of cultivated land 9.72%,Tongcheng has the largest area area;the eighth grade land area is 20673.17 hectares,accounting for 5.46%of the total cultivated land area,mainly in Taihu County;The counties are the most distributed.The tenth grade land area is 13195.06 hectares,accounting for 3.49%of the total cultivated land area,and is mainly located in Taihu County.(2)The available potassium content of cultivated land in Anqing city is at a medium and low level,accounting for 25.53%and 62.48%.The soil available potassium content levels in different counties are significantly different,mainly showing a distribution trend of high in the southeast and low in the northwest.Among them,the average value of available soil potassium in cultivated land in Wangjiang County is the highest,reaching 137.35mg.kg-1,and the lowest in Qianshan City,only 69.54 mg.kg-1.The level of soil available potassium content is also different on different soil types.The soil available potassium content in the fluvo-aquic soil is the highest,with an average of 164.50mg.kg-1,and the lowest in brown soil,only 74.7mg.kg-1.The overall level of available phosphorus in Anqing City's cultivated soil is relatively high and medium,accounting for 55.63%and 30.59%,respectively.The overall distribution trend is low in the northeast and high in the southwest,and the levels are moderate in Tongcheng and Yingjiang districts.,Only 11.94mg.kg-1,13.74mg.kg-1,higher in Wangjiang County,reaching 33.24mg.kg-1.The content of available phosphorus in cultivated land of Anqing City varies greatly among soils,with the highest content in brown soil,reaching 52.85 mg.kg-1,and the lowest in red clay,only 11.71 mg.kg-1.The organic matter content of the cultivated land in Anqing City was relatively high and medium levels,accounting for 49.01%and 50.95%,respectively.There are no obvious differences in the administrative area and the distribution of soil types,and they all fluctuate around 25g.kg-1.(3)In the application of the spatial interpolation method,the three methods of RF,OK,and IDW have the same trend in the prediction results of spatial distribution of soil nutrient content in cultivated land in Anqing City.However,from the perspective of prediction accuracy,in the spatial distribution prediction of soil nutrient content in Anqing City,the MAE and RMSE of RF are less than OK and IDW,and the R2 of RF is greater than OK and IDW.In the spatial distribution prediction of available phosphorus and available potassium in cultivated soil in Anqing,OK has the second MAE,RMSE,and R2;IDW has the largest MAE and RMSE,and the smallest R2.In the prediction of spatial distribution of soil organic matter content in cultivated land in Anqing,the MAE and RMSE of OK and IDW are relatively close,and the R2 of IDW is higher than that of OK.It shows that within the scope of the study area,RF has the highest prediction accuracy for cultivated soil nutrients,OK has higher prediction accuracy for cultivated soil available potassium and cultivated soil available phosphorus than IDW,and IDW has higher prediction accuracy for cultivated soil organic matter than OK.In the spatial interpolation application of RF,latitude,annual average temperature,soil parent material,elevation,longitude,and annual average precipitation are the main factors that affect the accuracy of RF prediction of soil available potassium content in cultivated land in Anqing.Longitude,latitude,annual average temperature,Plane curvature,elevation and annual average precipitation have a great influence on the prediction accuracy of RF for the prediction of soil available phosphorus in Anqing City.Longitude,latitude,plane curvature,elevation,annual average temperature and profile curvature predict the prediction of RF in Anqing City.Precision has a greater impact.The environmental variable factors that affect the soil nutrient content of cultivated land are basically the same,including longitude,latitude,annual average temperature,elevation,etc. |
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