SOIL QUALITY CRITERIA AND METHODOLOGIES OF FARMLAND GRADING
耕地分等中土壤质量指标体系与分等方法

Soil quality criteria are the most important bases for farmland grading. According to principles and methods of selecting indicators, introduced in this paper, it is pointed out that relatively stable characteristics of soil are usually used as criteria of farmland grading. Although mathematics methods, such as Main Component Analysis, Correlation Analysis, Variability Analysis, and Responding Duration Analysis of soil properties, are widely applied to select indicators for farmland grading, practical experiences as well as research results from soil science is proved to be the most effective way. Furthermore, method of summing the selected indicators' values is the reliable criterion for farmland grading.