Potential evaluation method on plow layer soil-stripping of cultivated land occupied by non-agricultural construction

Abstract: Stripping plow layer soil of cultivated land occupied by non-agricultural construction is an effective measure to reduce the contradiction between people and land, and to protect the cultivated land resources as city development and construction projects are increasing. Based on geographic information system (GIS) technology, from the aspects of the plow layer soil quality and the cultivated land quality, this study proposed a quantitative evaluation method about the potential of the plow layer soil-stripping of the cultivated land occupied by non-agricultural construction, and Jiangjin District of Chongqing was chosen as an example. Firstly, in order to ensure that plow layer soil-stripping was fertile, the indictors including organic matter, alkali-hydrolysable nitrogen (N), available phosphorus (P), available potassium (K), total N, total P and total K were chosen to evaluate the quality of plow layer soil in Jiangjin District. The fuzzy mathematical evaluation method was used in the determination of the membership degree about evaluation indicators of plow layer soil quality. The analysis hierarchy process was used in the determination of the weight of evaluation indicators. The fuzzy set weighted synthesis method was applied to establish a comprehensive evaluation model for plow layer soil quality in Jiangjin District. Based on ArcGIS, the quality of plow layer soil in Jiangjin District was discussed by using the ordinary Kriging method, which was divided into 5 levels. Then, in order to save the financial resource and human resource, reduce the project cost and realize the scale stripping and improve the benefit of project, the indicators of slope, soil thickness, distance to lane and single plot area were chosen to evaluate the quality of cultivated land occupied by non-agricultural construction in Jiangjin District. By using the Superposition Tool and Statistical Tool in Analysis Tools of ArcGIS, the cultivated land occupied by construction land in Jiangjin District from 2013 to 2020 could be inferred. With reference to the evaluation indicators of cultivated land quality, the cultivated land occupied by non-agricultural construction in Jiangjin District could be divided into 5 levels. Finally, according to the level of plow layer soil quality and the level of cultivated land quality, the potential of plow layer soil-stripping in Jiangjin District could be calculated and the plow layer soil-stripping could be divided into 3 levels. The results showed that: 1) The area of plow layer soil-stripping was 30.18 km2 in Jiangjin District, accounting for 76.39% of the total area of the cultivated land occupied by non-agricultural construction. The plow layer soil-stripping was mainly concentrated in northern and central Jiangjin District where existed booming economy, rapid development, flat terrain, contiguous cultivated land, convenient transportation, huge value-added potential. The levels of plow layer soil-stripping determined the priority of the plow layer soil-stripping and the reserve of soil resources. 2) The plow layer soil-stripping was scarce, and Level 1 and 2 were 0.32 and 4.64 km2, respectively, accounting for only 1.03% and 15.37% of the plow layer soil-stripping respectively. Therefore, the protection of cultivated land was a major task, and the high-quality soil layer in cultivated land occupied by non-agricultural construction should be stripped off in the development and construction in southwest hilly area. This study provides a scientific basis for the layout of regional non-agricultural construction and the protection of cultivated land, as well as some references for the subsequent use of plow layer soil.