Effects of Long-term Fertilization on the Soil enzyme Activities and Soil Nutrients of the Black and Dark Brown Soils

The soil enzyme activities and their corresponding nutrients of the black and dark brown soils under the same fertilizer applications of twenty-eight years were measured,and their relationships were analyzed.The objective was to clarify the effects of long-term fertilization on the soil enzyme activities and to figure out sustainable management of the black and dark brown soils.The results showed,compared to non-fertilization treatment,all the fertilization treatments could significantly increase the soil organic matter and total NPK contents of the black and dark brown soils,and enhance the soil urease,phosphatase,invertase and catalase activities,especially for the chemical fertilizer application combined with manure.There were good correlations among the soil enzyme activities and soil nutrients.Soil urease,phosphatase,invertase and catalase activities had a significant correlation with soil organic matter,total nitrogen,total phosphorus,nitrogen and available phosphorus contents.The effects of fertilizer applications on the black soil enzyme activities were more sensitive than those of the dark brown soil.The long-term chemical fertilizer application combined with manure could provide a good soil environment for the crop growth.