Diagnosis of Quality Characteristics and Obstacle Factors Induced by Mechanical Compaction in Fluvo-aquic Paddy Soils of the Jianghan Plain, China

Evaluating soil quality and diagnosing obstacles are critical for improving the ecological environment and maintaining soil productivity. Despite its importance, research on fluvo-aquic paddy soil quality in the Jianghan Plain, China, remains limited, even though the region is sexperiencing significant degradation due to intensified mechanization and inappropriate human activities. These factors have led to soil quality deterioration in specific areas. In this study, a comprehensive evaluation framework was developed to assess the soil quality of fluvo-aquic paddy soils in the Jianghan Plain. Principal component analysis was employed to select key physical and chemical indicators and establish a minimum data set (MDS). The cultivated-layer soil quality index (CLSQI) and the soil obstacle factor model were essential tools for evaluating cultivated-layer soil quality (CLSQ) and identifying its degradation characteristics. The findings revealed that the MDS consisted of six critical indicators: bulk density, organic matter, cation exchange capacity, pH, available phosphorus, and soil compactness. The correlation and Nash efficiency coefficients between CLSQI-MDS and CLSQI-TDS (total data set) were 0.693 and 0.124, respectively, indicating that MDS indicators can effectively replace the total data set (TDS) in evaluating CLSQ evaluation in fluvo-aquic paddy soils. The primary obstacles identified were low organic matter and cation exchange capacity levels, low pH values, and high soil compactness. Mechanical tillage practices and improper fertilization methods were identified as the primary causes of these issues. This study offers a theoretical foundation and empirical data for understanding the degradation characteristics of the cultivated layer in fluvo-aquic paddy soils. Moreover, it offers practical recommendations for improving cultivated-layer soil quality in the Jianghan Plain. • The Minimum data set (MDS) comprised bulk density (BD), soil organic matter (SOM), cation exchange capacity (CEC), pH, available phosphorus (AP), and soil compactness (SC). • The main obstacles indicators are SOM, CEC, pH and SC for fluvo-aquic paddy soil. • The soil barrier factor diagnosis model, soil quality evaluation model MDS are effectively integrated to form a complete, coordinated and accurate evaluation system.