Key Laboratory of Subtropical Agriculture Ecology, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China.
J Sci Food Agric. 2012 Mar 30;92(5):1112-8. doi: 10.1002/jsfa.4647. Epub 2011 Sep 23.
Organic substrates and calcium are important factors controlling organic matter turnover in Karst soils. To understand their effects on soil organic carbon (SOC) mineralization, an incubation experiment was conducted involving a control treatment (CK), the addition of a (14)C-labeled rice straw (T1), CaCO(3) (T2), and both (14)C-labeled rice straw and CaCO(3) (T3) to two types of Karst soils (terra fusca and rendzina) and a red soil from southwestern China.
Cumulative mineralization of the rice straw over 100 days in rendzina (22.96 mg kg(-1)) and terra fusca (23.19 mg kg(-1)) was higher than in the red soil (15.48 mg kg(-1); P < 0.05). Cumulative mineralization of native SOC decreased following addition of (14)C-labeled rice straw in the rendzina and terra fusca but increased in the red soil (negative and positive priming effects on native SOC). The turnover times of (14)C-labeled microbial biomass C (MBC) in the red soil, terra fusca and rendzina were 71 ± 2, 243 ± 20 and 254 ± 45 days, respectively. By adding CaCO(3), the accumulation of SOC was greater in the Karst soils than in the red soil.
Although the interactions between rice straw decomposition and priming effects on native SOC are not yet understood, there was considerable variation between Karst and red soils. Soil calcium was a positive factor in maintaining SOC stability. MBC from rice straws was stable in terra fusca and rendzina, whereas it was active in the red soil. The Karst soils (terra fusca and rendzina) used in this study benefited SOC accumulation.
有机底物和钙是控制喀斯特土壤有机质转化的重要因素。为了了解它们对土壤有机碳（SOC）矿化的影响，进行了一项包含对照处理（CK）、添加 14C 标记稻秸（T1）、CaCO3（T2）和 14C 标记稻秸和 CaCO3（T3）的培养实验，实验涉及中国西南部的两种喀斯特土壤（棕色石灰土和暗棕色土）和一种红壤。
在暗棕色土（22.96 mg kg-1）和棕色石灰土（23.19 mg kg-1）中，稻秸的累积矿化作用在 100 天内高于红壤（15.48 mg kg-1；P < 0.05）。添加 14C 标记稻秸后，暗棕色土和棕色石灰土中天然 SOC 的累积矿化作用降低，但红土中增加（对天然 SOC 产生负和正激发效应）。红土、棕色石灰土和暗棕色土中 14C 标记微生物生物量 C（MBC）的周转时间分别为 71 ± 2、243 ± 20 和 254 ± 45 天。添加 CaCO3 后，喀斯特土壤中的 SOC 积累量大于红土。
尽管稻秸分解与天然 SOC 激发效应之间的相互作用尚不清楚，但喀斯特土壤和红土之间存在相当大的差异。土壤钙是维持 SOC 稳定性的一个积极因素。稻秸中的 MBC 在棕色石灰土和暗棕色土中稳定，而在红土中活跃。本研究中使用的喀斯特土壤（棕色石灰土和暗棕色土）有利于 SOC 积累。
