Evaluating land capability using site assessment and land evaluation model in GIS in a watershed scale

Assessment of the capability of agricultural lands using a precise and systematic approach is vital to identify both the primary limitations and the potential of the land. With the growing need to protect farmlands, particularly in areas at high risk of degradation, developing an effective evaluation method is essential. This study focuses on site-specific conditions in China, where such risks are prevalent, and integrates the Land Evaluation and Site Assessment (LESA) method with ArcGIS to map and evaluate agricultural land potential. The LESA method comprises two critical components: Site Assessment (SA) and Land Evaluation (LE). SA considers non-soil related factors such as proximity to water sources, accessibility for agricultural machinery, and socio-economic considerations that affect agricultural productivity, while LE focuses on soil characteristics. The results indicate that a weighting of 0.4 was assigned to LE and 0.6 to SA, reflecting their respective importance in evaluating land potential. By integrating LESA with ArcGIS, it is categorized 7.59% of the region as "marginal land," 74.96% as "good land," and 17.45% as "best land" for crop production. Based on the results, is it recommended for lands classified as unsuitable or marginal, rangeland and agroforestry uses. We concluded that the integration of the LESA method with ArcGIS is a practical tool for land-use planners, helping to identify limitations and to optimize land-use planning for sustainable agricultural development.