知识与财富的链接
绿肥在培育健康土壤和保障水稻高产优质方面具有重要作用,然而高量有机物还田可能引发稻田土壤的甲烷（CH4）增排,须研发相应的管控路径。本研究通过在添加绿肥后的稻田土壤中施用田菁炭、过氧化钙、硫磺、2-氯乙烷磺酸钠和针铁矿5种CH4减排材料,研究其CH4减排效果,并针对减排效果较好的材料开展了作用机制研究。结果表明：与无绿肥（CK）相比,绿肥还田增加了稻田土壤CH4排放,添加减排材料后CH4排放降低。其中,与单独绿肥（GM）相比,添加田菁炭（GM+C）和硫磺（GM+S）CH4累积排放量降幅较小,分别为19.5%和23.8%;2-氯乙烷磺酸钠（GM+CES）相较于GM的CH4减排效果最佳,CH4累积排放量降低了66.7%,全球增温潜势（GWP）降低了 52.5%。培养结束时（90 d）,与 GM 相比,添加 2-氯乙烷磺酸钠的土壤 pH降低了 0.4个单位,产甲烷古菌mcrA丰度降低了29.9%。随机森林模型和相关性分析发现产甲烷古菌mcrA基因丰度与CH4排放呈显著正相关,说明产甲烷古菌是驱动绿肥稻田CH4排放的重要因子。研究表明,绿肥稻田土壤可通过添加减排材料实现CH4减排,本研究中以2-氯乙烷磺酸钠的效果最优,其专一、高效抑制产甲烷古菌群落,是未来值得探索的绿肥稻田土壤CH4减排材料。
Green manure plays an important role in cultivating healthy soil and ensuring high yield and quality of rice. However, it may trigger the increase of CH4 emission from green manure paddy soil for the return of high amount of organic matter to the field, and corresponding control pathways need to be developed. In this study, we investigated the CH4 emission reduction effects of five CH4 abatement materials, including sesbania biochar, calcium peroxide, sulfur, 2-chloroethanesulfonate, and goethite, after green manure returned to the paddy soils through simulation experiments, and carried out the mechanism studies for the materials with better abatement effects. The results showed that green manure returned to paddy field increased CH4 emission compared with no green manure（CK）, and CH4 emission was reduced by the addition of abatement materials. Among them, the cumulative CH4 emission reduction was smaller with the addition of the sesbania biochar（GM+C）and sulfur（GM+S）compared to green manure alone（GM）19.5% and 23.8%, respectively. And 2-chloroethanesulfonate（GM+CES）showed the best CH4 emission reduction compared to GM, with 66.7% reduction in cumulative CH4 emission and 52.5% reduction in global warming potential（GWP）. At the end of the incubation（90 d）, compared to GM, the addition of 2-chloroethanesulfonate decreased soil pH by 0.4 units and methanogenic archaea by 29.9%. Random forest modeling and correlation analyses revealed that the abundance of the mcrA gene of methanogenic archaea was significantly and positively correlated with CH4 emission, and this result suggests that methanogenic archaea is an important factor in driving CH4 emission from paddy soil. In summary, CH4 emission can be reduced through the addition of emission-reduction materials to green manure paddy field soils. Among these, 2- chloroethanesulfonate demonstrates the best performance in this study, specifically and efficiently inhibiting the methanogenic archaeal community, making it a promising material for future exploration in reducing CH4 emissions.
