ABSTRACT

A two-year field experiment was performed to investigate greenhouse gas emissions from rice straw return to different return depths and soil types. The experiment comprised of six treatments: without straw return (silty clay loam, SC; sandy loam, SL); straw return to topsoil (SCT, SLT); and straw return to subsoil (SCS, SLS). SCT and SLT released 2402.18 and 2494.01 kg ha⁻¹ more CO₂ than SC and SL in total, respectively. Straw return to topsoil and subsoil in both soil textures significantly increased CH₄ emissions. Compared to the total cumulative CH₄ fluxes in SC and SL, those of SCT and SLT increased by 239.62 and 131.34 kg ha⁻¹, and those of SCS and SLS increased by 125.07 and 89.93 kg ha⁻¹, respectively. SCT and SCS emitted 389.06 and 168.94 g ha⁻¹ less N₂O than SC in total, respectively. SL released 146.28 and 72.06 g ha⁻¹ more N₂O than SLT and SLS in total, respectively. The variations in the ratio of the total cumulative fluxes of CO₂ and CH₄, indicate that rice straw return to silty clay loam and subsoil tend to release more carbon in the form of CH₄ compared to sandy loam and topsoil, respectively.

摘要

进行了为期两年的田间试验，以研究稻草返回不同深度和土壤类型的温室气体排放。试验包括六个处理：不还稻草（粉质粘壤土，SC；砂壤土，SL）；秸秆还田（SCT、SLT）；和秸秆还田（SCS、SLS）。SCT 和SLT总共分别比SC 和SL释放了2402.18 和2494.01 kg ha ^{-1 的}CO ₂。在两种土壤质地中，秸秆返回表土和底土显着增加了 CH ₄排放。与SC和SL的CH ₄总累积通量相比，SCT和SLT分别增加了239.62和131.34 kg ha ^-1，SCS和SLS分别增加了125.07和89.93 kg ha ^-1， 分别。SCT 和SCS 排放的N ₂ O 总量分别比SC少389.06 和168.94 g ha ^-1。SL分别比 SLT 和 SLS释放的N ₂ O 总量多146.28 和 72.06 g ha ^-1。CO ₂和CH ₄总累积通量之比的变化表明，与砂壤土和表土相比，稻草返回粉质粘壤土和底土往往以CH ₄形式释放更多的碳。