Abstract: A long-term field experiment with four kinds of fertilization treatments was conducted in Fuxin of Liaoning Province. The fertilization treatments included: no fertilization (CK), chemical fertilizer (NPK), organic manure (M), and organic manure combined with chemical fertilizer (NPKM). Soil total organic carbon and key active carbon components were analyzed in order to offer a scientific basis for reasonable regional fertilization and sustainable agriculture management. The results showed that the total organic carbon content (TOC), organic carbon stock, microbial biomass carbon (MBC), dissolved organic carbon (DOC), particulate organic carbon (POC), labile organic carbon (LOC) contents in NPKM were higher than in the other treatments, and were 40.5%, 38.6%, 114.7%, 57.5%, 103.8%, and 97.6% higher than in the CK treatment, respectively. The MBC in organic manure treatment was obviously higher than that of without organic manure treatment. There were significant positive correlations between TOC, MBC, DOC, POC and LOC (P<0.05). Mixed application of organic and inorganic fertilizers significantly increased soil organic carbon content, indicating that it was the optimal fertilization model to improve soil fertility. The active carbon components responded sensitively to the fertilization and could be used as an index indicating the changes in soil total carbon.

Key words: truffles, principal component analysis, ecology, comprehensive evaluation.