Soil quality evaluation and limiting factor analysis in different microtopographies of hilly and gully region based on minimum data set

Abstract

Assessing soil quality across different microtopographies in hilly and gully regions is essential for enhancing the ecological environment, guiding plantation cultivation, and promoting sustainable development. In this study, soil quality was evaluated across six microtopographies based on 18 physical and chemical indicators. A minimum data set (MDS) was constructed using principal component analysis (PCA), and soil quality indices (SQI) were calculated for both the total data set (TDS) and MDS through membership function (MF), linear (S_L), and nonlinear scoring (S_NL) methods. The results indicate that the MDS for the soil quality evaluation of Caragana korshinskii plantation in the hilly and gully region is composed of moisture content (MC), total phosphorus (TP), total potassium (TK), pH and available nitrogen (AN), which can explain 74.801% of the information of TDS. The SQI calculated by the six methods are all extremely significantly correlated. In MDS, S_NL performs the best and is the closest to the calculation result of TDS. Soil quality varied significantly across microtopographies, with Gently sloped terrace exhibiting the highest quality and Gully the lowest, reflecting the strong influence of microtopography on soil properties and nutrient distribution. Total phosphorus (TP) was identified as the primary limiting factor, particularly in collapsed terrain. These findings not only provide a theoretical foundation and practical parameters for soil quality assessment in hilly and gully regions but also offer valuable insights for similar ecosystems globally, particularly in arid and semi-arid areas facing soil degradation and vegetation restoration challenges.