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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。
As global warming intensifies, the soil ring is receiving increasing attention as an important carbon sink in the global carbon cycle. Soil organic carbon fixation plays an important role in the greenhouse effect and climate warming. Dissolved organic matter (DOM) is the most active organic carbon pool in soil, and its content is significantly and positively correlated with soil CO2, CH4 and N2O emissions. DOM mineralization has become an important way of soil organic carbon loss. DOM can co-precipitate with Fe, Al and adsorb on the surface of soil minerals to change its biodegradability, thus stabilizing and retaining in the soil. DOM can make an important contribution to the accumulation of soil organic carbon. The chemical composition and structural characteristics of DOM affect its biodegradability and affect its precipitation adsorption effect. The stability mechanism is different, and there are differences in the contribution to soil organic carbon accumulation. At present, there is no universally accepted method to estimate the contribution of DOM to soil organic carbon. The specific numerical values vary greatly due to different estimation methods. Effective estimation methods still need further study.