Kan Zheng-Rong, Wang Zirui, Chen Wei, Virk Ahmad Latif, Li Feng-Min, Liu Jian, Xue Yaguang, Yang Haishui
College of Agriculture, Nanjing Agricultural University, Nanjing 210095, PR China.
State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, PR China.
J Environ Manage. 2023 Feb 15;328:116990. doi: 10.1016/j.jenvman.2022.116990. Epub 2022 Dec 9.
Methane (CH) is the main greenhouse gas emitted from rice paddy fields driven by methanogens, for which methanogenic abundance on CH production has been intensively investigated. However, information is limited about the relationship between methanogenic diversity (e.g., richness and evenness) and CH production. Three independent field experiments with different straw managements including returning method, burial depth, and burial amount were used to identify the effects of methanogenic diversity on CH production, and its regulating factors from soil properties in a rice-wheat cropping system. The results showed that methanogenic evenness (dominance) can explain 23% of variations in CH production potential. CH production potential was positively related to methanogenic evenness (R = 0.310, p < 0.001), which is driven by soil organic carbon (SOC), available phosphorus (AP), and nitrate (NO) through structure equation model (SEM). These findings indicate that methanogenic evenness has a critical role in evaluating the responses of CH production to agricultural practices following changes in soil properties. The SEM also revealed that SOC concentration influenced CH production potential indirectly via complementarity of methanogenic evenness (dominance) and available phosphorus (AP). Increasing SOC accumulation improved AP release and stimulated CH production when SOC was at a low level, whereas decreased evenness and suppressed CH production when SOC was at a high level. A nonlinear relationship was detected between SOC and CH production potential, and CH production potential decreased when SOC was ≥14.16 g kg. Our results indicated that the higher SOC sequestration can not only mitigate CO emissions directly but CH emissions indirectly, highlighting the importance to enhance SOC sequestration using optimum agricultural practices in a rice-wheat cropping system.
甲烷（CH₄）是稻田中由产甲烷菌驱动排放的主要温室气体，针对产甲烷菌丰度对CH₄产生的影响已进行了深入研究。然而，关于产甲烷菌多样性（如丰富度和均匀度）与CH₄产生之间关系的信息有限。在稻麦种植系统中，通过三个不同秸秆管理方式（包括还田方式、掩埋深度和掩埋量）的独立田间试验，来确定产甲烷菌多样性对CH₄产生的影响及其土壤性质调控因子。结果表明，产甲烷菌均匀度（优势度）可解释CH₄产生潜力23%的变异。CH₄产生潜力与产甲烷菌均匀度呈正相关（R = 0.310，p < 0.001），通过结构方程模型（SEM）可知，这是由土壤有机碳（SOC）、有效磷（AP）和硝酸盐（NO₃⁻）驱动的。这些发现表明，产甲烷菌均匀度在评估土壤性质变化后CH₄产生对农业实践的响应方面具有关键作用。SEM还揭示，SOC浓度通过产甲烷菌均匀度（优势度）和有效磷（AP）的互补性间接影响CH₄产生潜力。当SOC处于低水平时，增加SOC积累可改善AP释放并刺激CH₄产生；而当SOC处于高水平时，均匀度降低并抑制CH₄产生。检测到SOC与CH₄产生潜力之间存在非线性关系，当SOC≥14.16 g kg⁻¹时，CH₄产生潜力下降。我们的结果表明，较高的SOC固存不仅可以直接减少CO₂排放，还可以间接减少CH₄排放，突出了在稻麦种植系统中采用最佳农业实践增强SOC固存的重要性。
