Effects of biochar and plastic film mulching on greenhouse gases emissions from vegetable fields in Southwest China

The study investigated the effects of biochar application (BA) and plastic film mulching (PFM) on CH(4 )and N2O emissions in a hot pepper-radish rotation field in Southwest China. The research was conducted using the static chamber method from October 2019 to September 2020, encompassing the first radish growing season, the hot pepper growing season and the second radish growing season. Six treatments were applied: no mulching (NF) and PFM combined with three different BA rates (0, 20, and 40 t<middle dot>hm(-2)), labeled as NFBA0, NFBA20, NFBA40, PFMBA0, PFMBA2 0 and PFMBA40. The results indicated that neither PFM nor BA had a significant impact on CH(4 )emissions throughout the experimental period (P > 0.05). However, during the hot pepper growing season, PFM increased N2O emissions by 52.96 % - 53.27 % (P < 0.05). During the second radish growing season, BA reduced N2O emissions by 28.65 % - 63.70 % (P < 0.001). PFM also significantly boosted hot pepper and radish yields (P < 0.05), whereas BA had no significant effect on vegetable yields (P > 0.05). Additionally, PFM significantly decreased greenhouse gas intensity (GHGI) during both the radish and hot pepper growing seasons (P < 0.05). Although BA's effects on global warming potential (GWP) and GHGI were not significant during the first radish and hot pepper growing seasons, BA notably reduced GWP by 32.08 % - 67.53 % and GHGI by 37.26 % - 67.57 % during the second radish growing season (P < 0.01), with the lowest GWP and GHGI observed under the PFMBA20 treatment. In conclusion, PFMBA20 and PFMBA0 were recommended as the optimal agricultural practices for radish and hot pepper growing seasons, respectively, to achieve higher yields and lower greenhouse gas emissions simultaneously.