Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; School of Geography Sciences, Nanjing Normal University, Nanjing, 210047, China.
Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China; Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China.
J Environ Manage. 2019 Mar 15;234:226-236. doi: 10.1016/j.jenvman.2019.01.008. Epub 2019 Jan 8.
Crop residue decomposition has an important impact on soil organic carbon (SOC) sequestration and CO emission. Residue quality and management strategies are two important factors regulating decomposition process and SOC mineralization and greenhouse gas emission. In this study, a microcosm experiment in field condition was conducted on a silty loam (a Black soil) in Northeast China to investigate stover decomposition and soil CO emission characteristics as influenced by different crop cultivars and stover field incorporation methods. Stover from two popular maize cultivars Xianyu335 (XY) and Liangyu99 (LY) were applied in two modes (soil surface application vs soil incorporation) at a rate of 11 t ha, and CO efflux was monitored during the decomposition duration of 144 days. The structural transformation of carbon functional groups in maize stover were evaluated using solid state C-CPMAS NMR and elemental analysis techniques. Results showed that up to 71.7%∼86.9% (weight basis) of C and N in soil-incorporated stover was decomposed during the study period, which was significantly greater than the losses (32.8%∼55.3%) of C or N from the surface-applied stover for both maize cultivars; decomposition rates of main C functional groups were significantly higher in soil incorporation (71.1%∼88.8%) than in surface application (20.9%∼60.2%) systems. The concentrations of SOC, total N, available N, and microbial biomass C and N in soil were also higher with stover incorporation than surface application. Stover incorporation resulted in a notably lower CO emission rate and accumulative CO efflux (53.9-55.4 mol m) during the stover decomposition compared with surface application (57.4-67.0 mol m). Between the two maize cultivars, the LY stover showed a higher decomposition rate and greater capacity for SOC sequestration when incorporated into soil. The LY stover induced higher (16.8%) CO emission than XY when applied on soil surface, but no significant difference was found between the two cultivars when incorporated into soil. The results suggested that cultivar selection and stover management strategies have great potential in reducing soil CO emission while improving soil biochemical properties. Incorporating the LY stover into soil rather than surface mulching could enhance SOC sequestration and reduce CO emission.
作物残体分解对土壤有机碳（SOC）固存和 CO 排放有重要影响。残体质量和管理策略是调节分解过程以及 SOC 矿化和温室气体排放的两个重要因素。本研究采用田间微宇宙实验，在中国东北地区的粉质壤土（黑土）上，研究了不同作物品种和残体田间处理方式对秸秆分解和土壤 CO 排放特征的影响。以 11 t ha 的速率，采用两种模式（地表施用与土壤埋入）施用两种流行的玉米品种先玉 335（XY）和良玉 99（LY）的秸秆，在 144 天的分解期内监测 CO 通量。利用固态 C-CPMAS NMR 和元素分析技术评价了玉米秸秆中碳官能团的结构转化。结果表明，在研究期间，土壤埋入秸秆中高达 71.7%∼86.9%（以重量计）的 C 和 N 被分解，显著高于两种玉米品种地表施用秸秆的损失（32.8%∼55.3%）；土壤埋入处理中主要 C 官能团的分解速率（71.1%∼88.8%）明显高于地表施用处理（20.9%∼60.2%）。土壤中 SOC、总 N、有效 N、微生物生物量 C 和 N 的浓度也高于地表施用。与地表施用相比，秸秆埋入处理在秸秆分解过程中 CO 排放速率和累积 CO 通量（53.9-55.4 mol m）明显较低。在两种玉米品种中，LY 秸秆埋入土壤时分解速率较高，SOC 固存能力较强。LY 秸秆地表施用时的 CO 排放比 XY 高 16.8%，但埋入土壤时两种品种之间没有显著差异。结果表明，品种选择和秸秆管理策略在减少土壤 CO 排放的同时，具有提高土壤生化特性的潜力。将 LY 秸秆埋入土壤而不是地表覆盖，可以增强 SOC 固存，减少 CO 排放。
