Xiao Yi, Huang Rong, Zhang Zongjin, Wong Vanessa N L, Li Xingyu, Tang Xiaoyan, Luo Youlin, Wu Yingjie, Liu Jiang, Li Shiwei, Wang Changquan, Li Bing
College of Resources, Sichuan Agricultural University, Chengdu 611130, China.
College of Resources, Sichuan Agricultural University, Chengdu 611130, China; Key Laboratory of Investigation and Monitoring, Protection and Utilization for Cultivated Land Resources, Ministry of Natural Resources, Chengdu 611130, China.
J Environ Sci (China). 2025 Dec;158:420-434. doi: 10.1016/j.jes.2025.03.016. Epub 2025 Mar 11.
Soil microorganisms and labile soil organic carbon (SOC) fractions are essential factors affecting greenhouse gas (GHG) emissions in paddy fields. However, the effects of labile SOC fractions and microorganisms on GHG emissions from flooding to drying after organic fertilizer replacing for chemical fertilizer remain unclear. Here, a long-term experiment was conducted with four treatments: chemical fertilization only (control), organic fertilizer substituting 25 % of chemical N fertilizer (NM1), 50 % of chemical N fertilizer (NM2), and NM2 combined with crop straw (NMS). GHG emissions were monitored, and soil samples were collected to determine labile SOC fractions and microorganisms. Results revealed the GHG emissions in the NM2 significantly increased by 196.88 % from flooding to drying, mainly due to the higher CO emissions. The GHG emissions per kg of C input in NMS was the lowest with the value of 9.17. From flooding to drying, organic fertilizer application significantly increased the readily oxidizable organic carbon (ROC) contents and C lability; the NM2 and NMS dramatically increased the SOC and non-readily oxidizable organic carbon (NROC). The bacterial communities showed significant differences among different treatments in the flooding, while the significant difference was only found between the NMS and other treatments in the drying. From flooding to drying, changing soil moisture conditions causes C fractions and microbial communities to jointly affect carbon emissions, and the NMS promoted carbon sequestration and mitigated GHG emissions. Our findings highlight the importance of the labile SOC fractions and microorganisms linked to GHG emissions in paddy fields.
土壤微生物和不稳定土壤有机碳（SOC）组分是影响稻田温室气体（GHG）排放的重要因素。然而，在有机肥料替代化学肥料后，不稳定SOC组分和微生物对从淹水到干燥过程中温室气体排放的影响仍不明确。在此，进行了一项长期试验，设置了四个处理：仅施用化学肥料（对照）、有机肥料替代25%的化学氮肥（NM1）、50%的化学氮肥（NM2）以及NM2与作物秸秆结合（NMS）。监测了温室气体排放，并采集土壤样本以测定不稳定SOC组分和微生物。结果表明，从淹水到干燥过程中，NM2的温室气体排放量显著增加了196.88%，主要是由于较高的CO排放量。NMS中每千克碳输入的温室气体排放量最低，为9.17。从淹水到干燥，施用有机肥料显著增加了易氧化有机碳（ROC）含量和碳的活性；NM2和NMS显著增加了SOC和难氧化有机碳（NROC）。在淹水期，不同处理间细菌群落存在显著差异，而在干燥期，仅NMS与其他处理之间存在显著差异。从淹水到干燥，土壤水分条件的变化导致碳组分和微生物群落共同影响碳排放，NMS促进了碳固存并减少了温室气体排放。我们的研究结果凸显了稻田中与温室气体排放相关的不稳定SOC组分和微生物的重要性。
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