摘要
随着全球变暖的加剧,土壤圈作为全球碳循环中的重要碳库受到日益关注。土壤有机碳固定对大气温室效应和气候变暖有重要影响。溶解性有机质(DOM)是土壤中最活跃的有机碳库,其含量与土壤CO2、CH4、N2O的排放显著正相关,DOM的矿化成为土壤有机碳损失的重要途径。DOM可通过与Fe、Al共沉淀、吸附于土壤矿物表面而改变其生物降解性,从而在土壤中稳定和保留下来,对土壤有机碳积累中具有重要贡献。DOM的化学组成和结构特征影响其生物降解性,同时也影响其沉淀吸附效应。其稳定机制不同,对土壤有机碳积累的贡献也存在差异。目前估算DOM对土壤有机碳的贡献尚无普遍认可的方法,具体数值因估算方法不同而存在较大差异,有效的估算方法仍有待于进一步研究。
At a time of growing concern about global climate change,pedosphere deserves greater attention as an important carbon pool in global carbon cycle,because its carbon sequestering and stabilization have an significant influence on greenhouse effect and climate warming.Dissolved organic matter is considered as the most labile organic carbon pool in soil since the concentration of dissolved organic carbon has a significantly positive relation with CO2,CH4 and N2O released from soil.Therefore the mineralization of DOM becomes an important pathway of soil organic carbon loss.However,DOM can be precipitated by Al and Fe and absorbed to mineral surfaces,which is considered to be an important process of DOM stabilization against microbial decay and can contribute substantially to C pool in soils,especially for mineral subsoils.The biodegradability of DOM changes after DOM＇s absorption by different minerals or precipitation by different polyvalent cations,which leads to different contribution to DOM-derived soil C pools.The chemical composition and structural characteristics of DOM are not only an important controlling factor for DOM biodegradability,but also for the adsorption/precipitation capacity and the stability of absorption of organic matter.At present,no universally accepted method was available to estimate DOM＇s contribution to soil organic C,and the obtained values are greatly different between methods.Therefore,a more precise method should be further studied.
出处
《土壤通报》
CAS
CSCD
北大核心
2011年第6期1508-1514,共7页
Chinese Journal of Soil Science
基金
国家自然科学基金(40501065)
浙江省自然科学基金(Y307068)资助
关键词
溶解性有机质
生物可降解性
结构特征
土壤固碳
Dissolved organic matter
Biodegradability
Structural characteristics
Soil carbon sequestration
