Topsoil and Deep Soil Organic Carbon Concentration and Stability Vary with Aggregate Size and Vegetation Type in Subtropical China.
Topsoil and Deep Soil Organic Carbon Concentration and Stability Vary with Aggregate Size and Vegetation Type in Subtropical China.
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中国亚热带表土和深层土壤有机碳浓度和稳定性随团聚体大小和植被类型的变化而变化
DOI：
10.1371/journal.pone.0139380
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Shi JM
中科院分区：
文献类型：
--
作者：
Fang XM;Chen FS;Wan SZ;Yang QP;Shi JM
造林对土壤有机碳（OC）的影响，尤其是深层有机碳的影响，目前尚不清楚，也不清楚造林地土壤深层有机碳稳定性与植被类型和团聚体的关系。在这里，我们收集了表土（0-15厘米）和深层土壤（30-45厘米），从6对针叶林（CF）和阔叶林（BF）在20世纪90年代初在中国亚热带地区的森林。土壤团聚体分离的大小，通过干筛和OC的稳定性进行了测定，在71个培养天的闭罐碱吸收。BF处理土壤有机质含量和平均重径均高于CF处理。BF和CF表层土壤的累积碳矿化量（Cmin，mg CO2-C kg-1土）随团聚体的大小而变化，在深层土壤中，BF中较大团聚体的碳矿化量高于较小团聚体，而CF中较小团聚体的碳矿化量高于较大团聚体。土壤有机碳矿化的百分比（SOCmin，% SOC）一般较高，在较大的团聚体比在较小的团聚体。同时，在表层和深层土壤团聚体中，CF的SOCmin大于BF。与表土相比，深层土壤团聚体一般表现出较低的Cmin和较高的SOCmin。表层和深层土壤团聚体中全氮（N）和碳磷比（C/P）均表现出BF高于CF的趋势，而N/P仅在深层土壤团聚体中表现出相同的趋势。此外，土壤有机碳最小值与有机碳、全氮、C/P和N/P呈负相关。这项工作表明，植被恢复类型可能通过内部养分循环在土壤有机碳储存中发挥重要作用。土壤深度和团聚体的大小影响有机碳的稳定性，深层土壤有机碳的稳定性可以改变植被恢复约20年。
The impact of reforestation on soil organic carbon (OC), especially in deep layer, is poorly understood and deep soil OC stabilization in relation with aggregation and vegetation type in afforested area is unknown. Here, we collected topsoil (0–15 cm) and deep soil (30–45 cm) from six paired coniferous forests (CF) and broad-leaved forests (BF) reforested in the early 1990s in subtropical China. Soil aggregates were separated by size by dry sieving and OC stability was measured by closed-jar alkali-absorption in 71 incubation days. Soil OC concentration and mean weight diameter were higher in BF than CF. The cumulative carbon mineralization (Cmin, mg CO2-C kg-1 soil) varied with aggregate size in BF and CF topsoils, and in deep soil, it was higher in larger aggregates than in smaller aggregates in BF, but not CF. The percentage of soil OC mineralized (SOCmin, % SOC) was in general higher in larger aggregates than in smaller aggregates. Meanwhile, SOCmin was greater in CF than in BF at topsoil and deep soil aggregates. In comparison to topsoil, deep soil aggregates generally exhibited a lower Cmin, and higher SOCmin. Total nitrogen (N) and the ratio of carbon to phosphorus (C/P) were generally higher in BF than in CF in topsoil and deep soil aggregates, while the same trend of N/P was only found in deep soil aggregates. Moreover, the SOCmin negatively correlated with OC, total N, C/P and N/P. This work suggests that reforested vegetation type might play an important role in soil OC storage through internal nutrient cycling. Soil depth and aggregate size influenced OC stability, and deep soil OC stability could be altered by vegetation reforested about 20 years.