Evaluation index systems of soil quality in the Yellow River Delta

The soil quality was evaluated by using four schemes with Arcgis, in which the index weight was determined with correlation analysis method, the index membership degree with membership function. Results show that the soil quality evaluation based on GIS is fast and accurate. The difference between the results evaluated by the total contents of soil nutrients and by the soil available nutrients is not obvious and the two index schemes can be used alternatively. The results evaluated by soil organic matter and salt contents present similar outcomes to that by the comprehensive index system including soil total nutrients, available nutrients, organic matter, salt content, groundwater level and mineralization degree. Therefore, the organic matter and salt contents can be used to evaluate the soil quality in the case of limited evaluation data.