Mitigation of soil organic carbon mineralization in tea plantations through replacement of pruning litter additions with pruning litter derived biochar and organic fertilizer
Shaobo Zhang, Fuyin Huang, Shuai Guo, Ying Luo, Liping Zhang, Lan Zhang, Zeshuo Li, Shibei Ge, Huasen Wang, Jianyu Fu, Xin Li, Yan Peng
Abstract
Tea pruning litter is frequently added to soil to improve soil fertility and the C pool in tea plantations. However, the effects of different methods of incorporating tea pruning litter, such as direct return to the field, processing to organic fertilizer, and biochar, on soil organic carbon mineralization and its underlying mechanisms, especially microbial mechanisms, are still poorly understood. Therefore, we conducted an incubation experiment to explore the efficacy of tea pruning litter and its derivatives, biochar, and organic fertilizer, on the mineralization and chemical composition of soil organic C (SOC), labile organic C, functional gene abundance, microbial community composition, and activities of enzymes associated with C cycling in tea plantation soil. The results indicated that cumulative soil CO 2 emissions were ranked as pruned litter > organic fertilizer > biochar > control soil. The cumulative soil CO 2 emissions was decreased significantly by decreasing of the content of O-alkyl C and microbial biomass carbon, β-glucosidase/cellobiohydrolase activities, and the abundance of GH48 and cbh I ( P < 0.05). This indicates that lower CO 2 emissions following organic fertilizer and biochar addition (cf. pruned litter) were associated with a decrease in O-alkyl C content, β-glucosidase and cellobiohydrolase activities, as well as the abundance of GH48 and cbh I. More interestingly, changes in the microbial community structure, especially in some key species, such as Acidobacteria , Actinobacteria , Sordariomycetes , and Mortierellomycetes , can significantly affect the rate of SOC mineralization. Our study demonstrates that applying organic fertilizer and biochar derived from pruned litter significantly mitigated SOC mineralization compared to pruned litter application alone, and both have great potential for maintaining soil C stock in tea plantation soil. • Organic fertilizer and biochar can mitigate the SOC mineralization than pruned litter. • Lower SOC mineralization was related to lower the content of O-alkyl C and MBC. • Lower SOC mineralization was related to lower abundance of GH48 and cbh I. • Lower SOC mineralization was related to lower β-glucosidase/cellobiohydrolase.