Effect of Long-term Fertilizations on Particulate Organic Carbon and Enzyme Activities in a Brown Earth

Particulate organic carbon(POM-C) and enzyme activities in soil at 0-20cm depth of long-term located fertilizer experiment field for 27 years were measured and analyzed in order to illustrate the changes of POM-C and enzyme activities in soil and the relationship between them under different fertilizations.The results indicated that long-term application of pig manure significantly increased content of TOC,FPOM-C and OPOM-C in soil and the ratios of POM-C/TOC and FPOM-C/ OPOM-C.Application of chemical fertilizer alone increased soil TOC content but significantly decreased soil FPOM-C and OPOM-C contents and the ratios of POM-C/TOC and FPOM-C/ OPOM-C.Long-term application of pig manure significantly raised soil catalase,invertase,urease and neutral phosphatase activities.The soil enzyme activities were differently influenced by application of chemical fertilizer alone.The correlation analysis results showed that there were significant or extremely significant positive correlation relationship among the different SOC fractions and intimate relationship between the different SOC fractions and the soil enzyme activities.