Dynamic Changes of Soil Enzyme Activities in Microorganism Inoculants,Enzymes and Chemical Fertilizers in Different Proportions after Straw Returning Soil

The dynamic changes of soil enzyme activities,the relationship of soil enzyme activities with the contents of soil nutrients were investigated based on the experiment of microorganism inoculants,enzymes and chemical fertilizers in different proportions after straw returning soil in Hengqu county,Shaanxi province,China. The results showed that invertase and alkaline phosphatase had peaks of concentrations at filling stage and it was 58.30 mg,3.85 mg respectively. It was 4.7 times and 1.5 times before sowing of CK respectively. Urease and polyphenol oxidase peaked at mature stage and it was 4.85 mg,1.46 mg respectively. It was 3.2 times and 8.1 times before sowing of CK respectively. Microorganism inoculants,enzymes and chemical fertilizers in different proportions in straw returning soil could significantly increase the soil invertase,urease,alkaline phosphatase and polyphenol oxidase activities. The application of SFN+E+D fertilizers was more effective than others to increase soil enzyme activities. The significantly positive correlations were found between the activities of invertase,urease and alkaline phosphatase except polyphenol oxidase. Urease and alkaline phosphatase activities were correlated with soil nutrient contents except availble K while polyphenol oxidase varied un-remarkably. Invertase activities were reversely correlated with available K.