Zhou Yunchao, Pan Genxing, Li Lianqing, Zhang Xuhui, Zhang Pingjiu
Institute of Resources, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, Nanjing 210095.
Huan Jing Ke Xue. 2003 Jan;24(1):46-51.
Change of soil organic carbon (SOC) storage under global warming scenarios was paid much attention of the soil and global change studies. To address the features of SOC loss of paddy soils in response to global warming, the authors used 3 representative paddy soils from the Tai Lake region, China to incubate at laboratory respectively under 20 degrees C and 25 degrees C and the change dynamics of total organic carbon(TOC), soluble organic carbon (DOC) and microbial biomass carbon (MBC) were monitored in time intervals. The TOC dynamics could be described with primary reaction equations with the constants varied with soil types and incubation temperature. While soil warming strengthened TOC loss of a Fe-leached Stagnic Anthrosol and a Gleyic Stagnic Anthrosol, no significant difference of TOC was detected in a Fe-accumulic Stagnic Anthosol under different temperature incubations. Q10 quotient, a measurement of soil SOC sensitivity to warming, of the studied soils decreased in the order: 11.1-14.1 for the Gleyic Stagnic Anthrosol < 4.4-4.6 for Fe-leached Stagnic Anthrosol < 0.63-0.73 for the Fe-accumulic Stagnic Anthosol. This indicated that paddy soils could be a group of human managed soils with sensitive response to global warming, whereas the inter-soil group difference in this sensitivity may be greater than that existing between the soils from different eco-zones. The different patterns of DOC and MBC change during the incubation of the 3 studied soils were indicative of different features of soil microbial community of the studied 3 types of paddy soils, which influenced the carbon bio-availability under different temperatures. Thus, change of SOC pools due to soil warming can be accounted for not only by nature of SOC of the soils but changes of microbial activity and even the community associated with soil properties. This study evidences that SOC loss due to soil warming is not a temperature-controlled kinetically decomposition process at least. Further studies should be dedicated on the SOC loss in relation to the interactions between SOC-soil minerals-soil micro-biota.
全球变暖情景下土壤有机碳（SOC）储量的变化受到土壤与全球变化研究的广泛关注。为了研究水稻土SOC损失对全球变暖的响应特征，作者选取了中国太湖地区3种典型水稻土，分别在20℃和25℃下进行室内培养，并定期监测总有机碳（TOC）、可溶性有机碳（DOC）和微生物量碳（MBC）的变化动态。TOC动态可用一级反应方程描述，其常数随土壤类型和培养温度而变化。土壤升温增强了铁淋溶潴育水稻土和潜育潴育水稻土的TOC损失，但在不同温度培养下，铁聚积潴育水稻土的TOC未检测到显著差异。研究土壤的Q10商（衡量土壤SOC对升温敏感性的指标）排序为：潜育潴育水稻土11.1 - 14.1＜铁淋溶潴育水稻土4.4 - 4.6＜铁聚积潴育水稻土0.63 - 0.73。这表明水稻土可能是对全球变暖敏感响应的一类人为管理土壤，而这种敏感性在不同土壤类型间的差异可能大于不同生态区土壤间的差异。3种研究土壤在培养过程中DOC和MBC的不同变化模式表明了3种水稻土微生物群落的不同特征，这影响了不同温度下碳的生物有效性。因此，土壤升温导致的SOC库变化不仅可归因于土壤SOC的性质，还与微生物活性甚至与土壤性质相关的群落变化有关。本研究证明，至少土壤升温导致的SOC损失不是一个受温度控制的动力学分解过程。未来研究应致力于探讨SOC损失与SOC - 土壤矿物 - 土壤微生物区系之间相互作用的关系。
