农田土壤固碳作用对温室气体减排的影响

Effects of carbon sequestration in farmland ecosystem on the greenhouse gas emission

温室气体排放引起的全球气候变暖和平流层臭氧空洞已成为当前人们关注的环境问题之一。土壤碳库作为地表生态系统中最活跃的碳库之一,是甲烷、二氧化碳、一氧化二氮等温室气体的重要释放源,也是重要的吸收汇。因此,寻找农田土壤系统碳管理的有效方法已经成为缓解温室效应的重要科学问题。西方发达国家已将固碳农业作为环境管理的重要导向,应用颗粒分组13CNMR或CPMAS-NMR技术对土壤碳固定的机制研究指出微团聚体与矿物-粘粒复合体的相互作用是土壤有机碳稳定存在的主要方式,揭示了土壤有机碳的腐殖质转化及其与土壤矿物、金属氧化物结合的微观水平,且从土壤物理结构、化学组成和生物学特性等多学科交叉研究土壤有机碳的固定机理及其稳定机制。长期传统的土地利用方式和管理措施所导致的土壤有机碳含量、密度及垂直分布的变化是造成土壤碳库损失的主要原因,为了增加农业生态系统土壤有机碳的含量,土地利用方式和农业管理措施应该从增加有机碳输入量和减少有机碳矿化两方面着手,加强对农业土壤固碳潜力和土壤碳库稳定性影响因素的多角度研究。

Global climate change and destroy of ozonosphere due to Greenhouse gas emission is one of the most critical environmental problems today. As one of the largest and most active carbon pools of the earth surface ecosystem, the soil organic carbon （SOC） pool is not only a main greenhouse gas emission source in the earth which releases methane, carbon dioxide and nitrous oxide, but a carbon sink. Thus, it is a important thing to impulse efficient carbon management strategies in agro-ecosystem to mitigate greenhouse effect. Carbon sequestration agriculture has been recognized as the key approaches to sustainable agriculture in developed countries. Currently, researches in soil organic carbon （SOC） sequestration in soil has been increasing, such as SOC partitioning and binding behavior in soil aggregates （soil particle fractions） by ^13C NMR or CPMAS-NMR structure analysis technologies. It has been showed that interaction between microaggregates and mineral-humus-clay complexes is mainly responsible for the stabilization of soil organic carbon. The capacity of carbon storage in soil is also related to the size of micro-aggregates. There is an urgent need to enforce multidisciplinary researches to illustrate the influences of physical, chemical and biological features on the mechanisms of soil carbon sequestration in agricultural soil including soil aggregate, soil structure, nutrition and agriculture practices. Soil organic carbon loss is strongly affected by changes on SOC content, SOC density and vertical distribution which resulted from long-term intensive agriculture and management practices. Land use and management practices that lead to improvement in plant biomass pro- duction would likely to increased carbon inputs. Thus, the focuses that the study about the influences of carbon sequestration and soil organic carbon stability should be strengthened were put forward in order to establish reasonable policy of agricultural management, consequently to alleviate greenhouse effect.