Effect of sugarcane vinasse on soil physicochemical properties and oxidoreductase enzymes

An experiment was conducted in sugarcane field to study the effect of six treatments vinasse application (four application rates), CK1 (non-fertilizer) and CK2 (chemical fertilizer) on soil physicochemical properties, catalase and polyphenol oxidase activity. The results show that total N, Cl^-, organic matter (OM), humic acid (HA) content of soil improves under vinasse treatments. Catalase and polyphenol oxidase activity increase abnormally at sugarcane settling stage and then sharply decrease to CK2 level at sugarcane maturity stage. Catalase activity has extremly significant positive correlations with total N, OM, HA, and significant positive correlations with fulvic acid fraction(FAF), humic acid fraction (HAF) and Cl^- (r_0.05=0.811, r_0.01=0.917, n=6). An obvious significant correlation also exists between polyphenol oxidase activity and OM, HA and Cl^- content. At the latter stage of sugarcane growth, total N, OM, Cl^- sugarcane fields are lower than in 75 ton treatment in sugarcane fields. Soil fertility, OM and HA content, and catalase and polyphenol oxidase activity are higher in the four vinasse treatments than in CK1 and CK2 treatments. Sugarcane plantation absorbs vinasse nutrient and purifies soil environment when treated with vinasse.