农田固碳措施对温室气体减排影响的研究进展

农田是CO2,CH4和N2O三种温室气体的重要排放源,在全球范围内农业生产活动贡献了约14%的人为温室气体排放量,以及58%的人为非CO2排放,不合理的农田管理措施强化了农田温室气体排放源特征,弱化了农田固碳作用。土壤碳库作为地球生态系统中最活跃的碳库之一,同时也是温室气体的重要源/汇。研究表明通过采取合理的农田管理措施,既可起到增加土壤碳库、减少温室气体排放的目的,又能提高土壤质量。农田土壤碳库除受温度、降水和植被类型的影响外,还在很大程度上受施肥量、肥料类型、秸秆还田量、耕作措施和灌溉等农田管理措施的影响。本文通过总结保护性耕作/免耕,秸秆还田,氮肥管理,水分管理,农学及土地利用变化等农田管理措施,探寻增强农田土壤固碳作用,减少农田温室气体排放的合理途径。农田碳库的稳定/增加,对于保证全球粮食安全与缓解气候变化趋势具有双重的积极意义。在我国许多有关土壤固碳与温室气体排放的研究尚不系统或仅限于短期研究,这也为正确评价各种固碳措施对温室气体排放的影响增加了不确定性。

Advance in Evaluation the Effect of Carbon Sequestration Strategies on Greenhouse Gases Mitigation in Agriculture

Agricultural field is an important source for three primary greenhouse gases(GHGs),including CO2,CH4 and N2O.Unreasonable agricultural managements increase GHGs and decrease the effect of soil carbon sequestration.Agricultural activities generate the largest share,58% of the world’s anthropogenic non-carbon dioxide(non-CO2) emission,and make up roughly 14% of all anthropogenic GHG emissions.And soil carbon pool is the most active carbon pools in ecosystems.In addition,soil carbon pool could be a source or sink of GHGs. Many researches indicated that the optimized agricultural practices play an important role not only in mitigating GHGs emission and increasing reserves of soil carbon pool,but also in improving soil quality.Both temperature,precipitation,vegetation types and application of fertilizers/straws,tillage and irrigation management practices can exert significant effects on carbon sequestration in soil.This paper analyzes the practices of conservation tillage/ no tillage,residue return,nitrogen fertilizer and water managements,agronomy managements and land-use change and proposes the reasonable ways on increasing carbon sequestration potential and mitigation GHGs mission.The stable or increasing of soil carbon sequestration plays an important role in guarantying global food security and mitigation climate change.Many of researches about soil carbon sequestration and greenhouse gas emissions are not system or limited to short-term studies in China,which increases the uncertainly for the correct evaluation of carbon sequestration management practices on greenhouse gas emissions.