生物炭施用3年后对稻麦轮作系统CH4和N2O综合温室效应的影响

本试验对比观测研究了在稻田土壤中经3年陈化后的生物炭(B_3)和新施入生物炭(B_0)对稻麦轮作系统CH_4和N_2O综合温室效应和温室气体强度的影响,旨在明确生物炭对土壤温室气体排放的长期效应.田间试验设置4个处理,分别为对照(CK)、施用氮肥不施用生物炭(N)、施用氮肥和新生物炭(NB_0)以及施用氮肥和陈化生物炭(NB_3)处理.结果表明:NB_0和NB_3处理均显著提高了稻田土壤pH值、有机碳和全氮含量,并且显著影响与温室气体排放相关的微生物潜在活性.与N处理相比,NB_3处理显著增加了作物产量,增幅14.1%,并且显著降低了CH_4和N_2O排放,降幅分别为9.0%和34.0%;而NB_0处理显著增加作物产量,增幅9.3%,显著降低N_2O排放,降幅38.6%,但增加了CH_4排放,增幅4.7%;同时NB_0和NB_3处理均能降低稻麦轮作系统的综合温室效应和温室气体强度,且NB_3处理能更有效地减少温室气体的排放并提高作物产量.在土壤中经3年陈化后的生物炭仍然具有固碳减排能力,因此,施用生物炭对稻麦轮作系统固碳减排和改善作物生产具有长期效应.

Effects of biochar application three-years ago on global warming potentials of CH4 and N2O in a rice-wheat rotation system.

To evaluate the long-term effects of biochar amendment on greenhouse gas emissions (GHGs), a field experiment was conducted to examine the effects of 3-year field-aged biochar (B₃) and fresh biochar (B₀) on global warming potential (GWP) and greenhouse gas intensity (GHGI) of methane (CH₄) and nitrous oxide (N₂O) in a typical rice-wheat rotation system. Four treatments were established as control without nitrogen fertilizer (CK), urea without biochar (N), urea with fresh biochar amended in 2015 (NB₀), and urea with 3-year field-aged biochar amended in 2012 (NB₃). Results showed that both the NB₀ and NB₃ treatments obviously increased soil pH, soil organic carbon (SOC), total nitrogen (TN) and influenced the potential activity of functional microorganisms related to GHGs compared to the N treatment. Relative to the N treatment, the NB₃ treatment significantly improved crop yield by 14.1% while reduced the CH₄ and N₂O emissions by 9.0% and 34.0%, respectively. In addition, the NB₀ treatment significantly improved crop yield by 9.3%, while reduced the N₂O emission by 38.6% though increased the CH₄ emissions by 4.7% relative to the N treatment. Moreover, both the NB₀ and NB₃ treatments could significantly reduce both GWP and GHGI, with NB₃ being more effective in simultaneously mitigating the GHGs emissions and enhancing crop yield. Since field-aged biochar showed obvious effects on GHGs mitigation and carbon sequestration after 3 years, biochar incorporations had long-term effect on GHGs mitigation and crop production in the rice-wheat rotation system.