Development of a simplified health assessment method for saline cultivated land using soil and crop indicators

• Development of a method for evaluating integrated soil-crop systems for fertility. • Coastal saline-alkali cultivated land are currently in an unhealthy condition. • Soil amendments are more effective for improvement than other farming practices. Land salinization threatens the sustainable use of approximately 7.7 million hectares of arable land worldwide. The lack of a specialized soil health assessment system for saline cultivated land hampers accurate evaluation and improvement efforts. To address this issue, this study conducted a meta -analysis of 264 datasets from coastal saline lands in eastern China to identify key soil and crop evaluation indicators. The results revealed notable differences in seven soil indicators and four crop indicators. Principal component analysis (PCA) and correlation analysis were used to select a minimum dataset (MDS), which explained 70.41% of the variation in the soil subsystem and 71.03% in the crop subsystem. The integrated fertility index (IFI) was calculated using a modified Nemerow formula, with weights of different indicators assigned by PCA. Then a grading scale based on IFI categorized the health status of saline cultivated land as “healthy”, “sub-healthy” or “unhealthy”. Furthermore, a time-series assessment method was introduced to illustrate the trends in soil health over time. Three main improvement strategies (cultural practices, cultivation of salt-tolerant crops, and the application of soil amendments) were evaluated through empirical studies. Soil amendments, such as organic fertilizers and microbial fungicides, produced the most significant improvements in soil fertility. A simplified soil fertility assessment framework was developed for saline cultivated land, emphasizing practicality and operability while ensuring scientific rigor. This study provides a methodological reference for assessing soil health in saline lands and evaluating the effectiveness of improvement strategies.