LAUSR

The non-point source pollution of drinking water source areas is a global issue which is mainly caused by unreasonable management of the commercial forests growing in the upstream areas. However the occurrence and specific mechanism of runoff pollution in these areas have not been approached. In order to clarify the factors influencing the non-point source pollution in the area, the test plot in Fushi Reservoir watershed covered by Phyllostachys edulis plantations with pure and modified stands was chosen, and the characteristics of soil chemical properties, enzyme activities and the coupling between soil factors and surface runoff of were initially analyzed, the relationship between soil factors and surface runoff pollutants was examined using redundancy analysis. The results showed that pH, soil nitrate reductase (S-NR) and catalase (S-CAT) were the key factors affecting the differentiation of water quality in surface runoff. The total nitrogen (TN) concentration in surface runoff was positively correlated with S-NR but negatively correlated with pH, TN and alkali-hydrolyzed nitrogen (AN) concentrations in soil. The total phosphorus (TP) concentration was negative correlation with soil pH and TP. In addition, the permanganate index (CODMn) concentration has positive correlation with urease (S-UE), acid phosphatase (S-ACP) and organic matter (SOM) in soil. These results suggest that soil enzyme activities are more sensitive than soil nutrient status, and could be used as indicators of non-point source pollution assessing. Moreover, pollution in this area could be effectively controlled by enhancing vegetation coverage and ameliorating soil environment.