Mitigating Nitrous Oxide Emissions from Tea Field Soil Using Bioaugmentation with a Trichoderma viride Biofertilizer

Land-use conversion from woodlands to tea fields in subtropical areas of central China leads to increased nitrous oxide (N(2)O) emissions, partly due to increased nitrogen fertilizer use. A field investigation of N(2)O using a static closed chamber-gas chromatography revealed that the average N(2)O fluxes in tea fields with 225 kg N ha(−1) yr(−1) fertilizer application were 9.4 ± 6.2 times higher than those of woodlands. Accordingly, it is urgent to develop practices for mitigating N(2)O emissions from tea fields. By liquid-state fermentation of sweet potato starch wastewater and solid-state fermentation of paddy straw with application of Trichoderma viride, we provided the tea plantation with biofertilizer containing 2.4 t C ha(−1) and 58.7 kg N ha(−1). Compared to use of synthetic N fertilizer, use of biofertilizer at 225 kg N ha(−1) yr(−1) significantly reduced N(2)O emissions by 33.3%–71.8% and increased the tea yield by 16.2%–62.2%. Therefore, the process of bioconversion/bioaugmentation tested in this study was found to be a cost-effective and feasible approach to reducing N(2)O emissions and can be considered the best management practice for tea fields.