Soil enzymes as indicators of saline soil fertility under various soil amendments

Soil salinity, caused by natural of anthropogenic factors, has been recognized as a challenge to cultivation. Coastal saline soil is widely distributed in China. The relationships between soil properties and enzyme activities under different amendment types were investigated in Yellow River Town, Kenli County, Shandong Province. The aim of our study was to determine the appropriate treatments for alleviating salinity. Hekang (a saline soil modifier), chemical fertilizers, microbial inoculant, and organic fertilizer were applied to coastal saline soil in this study. The results showed that urease and catalase activities were improved under conditions of Hekang, organic fertilizer and microbial inoculant, but not under single chemical fertilizer applications. All the amendment applications improved alkaline phosphatase activity. Urease activity, alkaline phosphatase activity and catalase activity were all significantly positively correlated with soil organic matter (SOM) or soil nitrogen (N), and were negatively correlated with soil salinity or pH. In addition, Catalase activity was significantly negatively correlated with available phosphorus (P); urease activity showed a significantly positive correlation with soil available nitrogen (N) and a negative correlation with available P or available potassium (K).