生物质炭对农田温室气体排放的作用效应及其影响因素探讨

Effect and its influencing factors of biochar on agricultural greenhouse gases emissions

气候变暖已成为当今全球关注的焦点。农田生态系统作为CO2、CH4、N2O等温室气体的主要排放源,在全球温室效应中起重要作用。近年来,由于生物质炭在改善土壤性质,提高土壤碳汇和控制农业温室气体排放方面的巨大应用潜力,特别是对土壤碳的增汇减排作用,已成为土壤学和环境科学的研究热点。目前,关于生物质炭在农田温室气体排放方面的影响研究主要集中在我国华中、太湖平原、成都平原等地。然而由于受空间地域、实验条件等因素的差异,众多学者开展生物质炭作用于农田温室气体排放的研究结果不尽相同,也未曾见有报道从影响因素的角度深入探讨其作用机制。综述对比了近几年来国内外关于生物质炭对农田温室气体排放的影响研究,并从生物质炭的种类、施炭量、应用的土壤类型以及耕作方式和施肥条件等因素探讨了生物质炭对农田温室气体排放的作用机制。旨在通过改变生物质炭的种类和施炭量等条件,从而为抑制农业温室气体的排放乃至缓解全球气候变化提供可靠的科学依据。综合各项研究发现,秸秆炭在抑制农田温室气体排放方面要优于其他种生物质炭;40 t.hm-2的施炭量是一个既能提高作物产量又能实现固碳减排目标的较好选择;单作物耕作方式和合理的保护性耕作技术有利于减少农田温室气体的排放;在肥料的施用选择上,施用氮磷钾有机肥比普通氮肥更能有效地减少农田温室气体的综合排放效应。然而,从微生物活性和群落结构变化的角度深入探讨生物质炭作用于农田温室气体排放的微观机理及其温室气体减排还仍需进一步的研究。

Climate wanning has been the focus of the global attention at present. Agricultural field ecosystem as a main source of CO2, CH4 and N20 agricultural green house gases （GHGs） emissions, which play significant role in greenhouse effect. The research on biochar has become a hotspot in recent years due to its potential application in improving soil properties, increasing carbon sink and controlling GHGs emissions, especially for carbon abatement by the increasing of carbon sink in soils. Most reports on GHGs emissions by biochar amendment are concentrated on Tai Lake and Chengdu plain or Central China. But regional differences and experiment conditions make many researchers＇ study are different. Meanwhile, few reports are elucidates the mechanism of biochar affecting GHGs emissions from the influencing factors point of view. Comparison of the effects of biochar on GHGs releases in recent years from the domestic and foreign research is summarized here, and the mechanism is discussed as well from the perspective of biochar species and amendment, soil type, tillage, fertilization and so on. Changing conditions like species and amendments of biochar are aimed at controlling GHGs emission and even mitigating global climate change. The results by comprehensive analysis show that straw biochar is superior to another in controlling GHGs effiux; 40 t＇hm2 amendment may be a good choice to improve crop yield and carbon sink by reducing GHGs emissions; single crop tillage and reasonable conservation tillage are good for decreasing GHGs releases; NPK fertilizers are better than N fertilizers in order to reducing comprehensive emissions effect in terms of fertilizing. However, a further research about micro-mechanism of biochar on agricultural GHGs emissions and its reduction measures is still needed from the perspective of microbial activities and community structure change.