干湿循环老化生物炭对稻田温室气体排放及产量的影响OA

The carbon sequestration and emission reduction effects of biochar in paddy fields are influenced by its aging process.To this end,a two-year pot experiment was conducted in Nanjing,Jiangsu Province,to investigate the impacts of biochar aged by dry-wet cycles on greenhouse gas(CH4 and N2O)emissions,rice yield,and greenhouse gas intensity(GHGI).Through an indoor incubation experiment(2023),the natural dry-wet cycles of paddy fields(one cycle every 3 days,10 cycles in total)were simulated to pre-age the biochar.Four treatments were established:fresh biochar(C0),3-cycle aged biochar(C3),6-cycle aged biochar(C6),and 10-cycle aged biochar(C10).Gas emissions were measured using the in-situ static chamber method,and GHGI was calculated based on yield data.The results showed that the C6 treatment yielded the optimal carbon sequestration and emission reduction effects.Compared with C0,the C6 treatment significantly reduced the fluxes and cumulative emissions of soil CH4 and N2O(p<0.05):cumulative CH4 emissions decreased by 18.33%and 23.86%in 2023 and 2024,respectively,while cumulative N2O emissions decreased by 11.03%and 15.19%,respectively.Simultaneously,the C6 treatment significantly increased rice yield(p<0.05)by 11.17%and 14.66%in the two years,respectively,and minimized GHGI,showing significant reductions of 25.40%and 32.26%compared to C0(p<0.05).These findings indicate that biochar moderately aged through dry-wet cycles(6 cycles)can optimally achieve the synergistic goals of mitigating greenhouse gas emissions and increasing crop yield in paddy fields.This study provides new strategies and a theoretical basis for the precise application of biochar in agricultural production.