摘要
土壤碳循环是与全球气候变化密切相关的重要地球表层系统过程,是国际地学和生态学界近年来的热点领域。本文简要概述了国际土壤碳循环研究的进展和发展态势,着重讨论了中国稻田土壤固碳研究已获得的认识。提出碳循环研究越来越走向与生物学的结合,且越来越依赖于长期试验和观测。中国稻田土壤的固碳水平、潜力已有较丰富的认识和资料积累,在团聚体尺度上也开展了较多的固碳机理的研究,包括物理保护、化学结合、生物学的稳定等。无论是野外还是实验室的培养均表明稻田土壤碳矿化潜力较低,这与团聚体的物理保护有关外,还与稻田土壤中存在的碳的化学结合而稳定的机制有关;固碳与农田生态系统生产力和生态服务功能的耦合机制是当前稻田土壤固碳研究的中心内容,一些研究已经表明生物多样性可能是控制碳稳定和温室气体减排与生产力提高的关键因素。未来研究的重点是定量表征固碳中碳更新的关键环节,同时需要加强对作物-土壤微生物相互作用对碳输入、转化和固定的影响及机理的研究。中国稻田土壤固碳与农业发展意义值得进一步重视。
C cycling of soils is a critical process of Earth surface system closely related to global climate change. This review paper summarizes the main achievements of studies on C cycling of paddy soils of China while highlighting the global trends. C cycling processes and the C footprints have been increasingly characterized by means of molecular micro- biology in conjunction with C and N isotopes tracing methodologies. Soil productivity and the ecological services are being focused when dealing with C sequestration and mitigation in agriculture. Long-term ecosystem experiments are increasingly involved in monitoring and modeling C cycling and the dynamics. While many studies of C sequestration have demonstra- ted well the C storage and stock in paddy soils, much attention have been paid to C sequestration processes in scale of mi- cro-aggregates regarding the formation, turnover and the physical protection and transformation of C input to paddies. Some of laboratory incubations and field monitoring works have clarified that C in paddy soils is more or less stable with relatively low mineralization rates both under aerobic and anaerobic conditions, which may suggest that C in paddy soils is more intense protected and chemically bound to soil components such as oxyhydrates rich in them. As a global trend, the coupling mechanism of C sequestration and crop productivity as well as the ecological services are being challenged. It is evidenced in some of studies that biodiversity may have controls on C cycling and GHGs production coping with the crop productivity. However, quantitative characterization of C turnover and C sequestration processes is still in debt of paddy soils. The interactive effects of crop-soil-microbe on C sequestration and GHGs production from paddy soils deserve further holistic studies with new hypothesis. The role of C sequestration in China＇ s climate change mitigation should be further evaluated for a better climate policy of agriculture.
出处
《土壤学报》
CAS
CSCD
北大核心
2008年第5期901-914,共14页
Acta Pedologica Sinica
基金
国家自然科学基金重点项目(40231016)
国际合作重大项目(40270010092)
教育部重大项目(2007)资助
关键词
碳循环
土壤有机碳
稻田
气候变化
生物多样性与生产力
C cycling
Soil organic carbon
Paddy soils
Climate change
Biodiversity and productivity
