Characteristics of soil enzyme activities and their relationships with soil properties in southern Ningxia Loess hilly region

The linkage between soil enzyme activities and soil properties was studied. Results show that soil organic matter has a significant relationship with soil total N, available P and available K as well as with soil enzyme activities. Soil enzyme activities are improved greatly with increase in soil organic matter due to their participatory role in the decomposition and transformation of organic matter.Urase and sucrase activities are significantly related to soil N, P, K contents. Sucras activity is especially strongly related to available K.From path analysis, the sequence of soil properties based on their direct effect on urase activity is: organic matter＞available K＞available N＞cation exchange capacity(CEC)＞total N＞available P＞physical clay＞pH,meaning that organic matter is the most important factor that affects urase activity and alkaline phosphatase and available K is the most important factor for sucrase activity.