Effect of fertilization on labile carbon pools and emissions of greenhouse gas in soils of Chinese chestnut stands

Soil greenhouse gas (CO2 and N2O) emission rates were analyzed by the method of static closed chamber/GC technique, and soil labile organic carbon pools, including watersoluble organic carbon (WSOC) and microbial biomass carbon (MBC) concentrations, were determined as well in the typical Chinese chestnut (Castanea mollissima) stands of Linan, Zhejiang Province. There were four different fertilizer treatments, including no fertilizer (CK), inorganic fertilizer (IF), organic fertilizer (OF), and half organic plus half inorganic fertilizer (OIF). The objectives of this study were to investigate the effects on soil CO2 and N2O emission rates and soil labile organic carbon pools in different fertilization treatments and reveal the relationships between greenhouse gas emissions and soil labile carbon pools. The results show that the fertilization could significantly increase emissions of CO2 and N2O in Chinese chestnut stands (P 0.05). Compared with the CK treatment, the CO2 emission rates in IF, OF, and OIF treatments are increased by 87%, 38%, and 61%, respectively, after one month of fertilization, and are increased by 51%, 43%, and 64%, respectively, after six months of fertilization. Meanwhile, the N2O emission rates in IF, OF, and OIF treatments are increased by 101%, 67% and 95%, respectively, after one month fertilization, and are increased by 21%, 29%, and 47%, respectively, after six months of fertilization. Additionally, the fertilization could significantly increase the WSOC and MBC concentrations (P 0.05). The soil CO2 and N2O emission rates have significant positive correlations with soil WSOC concentrations (P 0.05), but have no significant correlations with soil MBC concentrations. We suggest that increasing soil WSOC concentration by fertilization may contribute to increase soil greenhouse gas emission in Chinese chestnut stands.