The trajectory of soil development and its relationship to soil carbon dynamics
The trajectory of soil development and its relationship to soil carbon dynamics
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土壤发育轨迹及其与土壤碳动态的关系
DOI：
10.1016/j.geoderma.2021.115378
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发表时间：
2021
期刊：
影响因子：
6.1
通讯作者：
J. Harden
中科院分区：
文献类型：
--
作者：
C. Lawrence;M. Schulz;C. Masiello;O. Chadwick;J. Harden
土壤有机碳（SOC）与土壤矿物质的关系在土壤有效水分（估计为降水减去蒸散量）的响应中表现出阈值关系。为了更好地表征水分在土壤形成过程中影响有机碳储存机制中的作用，我们比较了两个不同时间序列地点的土壤：圣克鲁斯和马托尔河海相阶地，它们共同形成了一个土壤气候年龄梯度（即气候-时间序列）。我们的研究结果表明，有效土壤水分的变化可能会驱动土壤沿着不同的成土轨迹发育，从而导致次生风化产物的形式和深度分布的变化。特别是，残余金属铁和铝与风化过程中积累的次生矿物类型直接相关，这些变化与土壤内部和土壤之间有机碳储存和长期保存的差异有关。随着时间的推移，这些土壤发育的差异可能导致“成土阈值”，从而进一步区分土壤特征并影响有机碳动态。在这种情况下，成土阈值以富含粘土的泥质层的形式出现，一旦形成，就会抑制水运移，使浅层和深层土壤环境分离，并可能限制深层土壤的有机碳输入和增加微生物循环。我们的数据表明，在较干燥的圣克鲁斯土壤中，粘土层发育有利，高岭石是主要的次生风化产物。相比之下，马托勒年代序列土壤中较大的有效水分驱动了不同的风化轨迹，其特征是更多无定形次级矿物的积累。因此，Mattole土壤并没有表现出泥质层发育，而是在所有采样深度都具有较大的有机碳积累。总的来说，我们的研究结果说明了气候（即湿度）和时间的相互作用如何影响土壤发育的轨迹以及有机碳储存和保存的动态。
It has been postulated that the amount of soil organic carbon (SOC) associated with soil minerals exhibits a threshold relationship in response to effective soil moisture (estimated as precipitation less evapotranspiration). To better characterize the role of moisture in influencing mechanisms of SOC storage during pedogenesis, we compare soils from two different chronosequence sites: the Santa Cruz and Mattole River marine terraces that together form a soil age-by-climate gradient (i.e., climo-chronosequence). Our results demonstrate how variation in the effective soil moisture may drive soil development along divergent pedogenic trajectories, resulting in variations in the form and depth distribution of secondary weathering products. In particular, the residual metals Fe and Al are directly related to the type of secondary minerals that accumulate during weathering, and these variations are coupled to differences in the storage and long-term preservation of SOC both within and between soils. Over time, these differences in soil development may lead to ‘pedogenic thresholds’ that further differentiate soil characteristics and influence SOC dynamics. In this case, the pedogenic threshold takes the form of clay-rich argillic horizons that once formed, inhibit aqueous transport, decouple shallow and deep soil environments, and potentially limit SOC inputs and increase microbial recycling in deep soils. Our data suggest argillic horizon development is favorable in the drier Santa Cruz soils, where kaolinite is the dominant secondary weathering product. In contrast, greater available moisture in soils of the Mattole chronosequence drive a different weathering trajectory characterized by the accumulation of more amorphous secondary minerals. As a result, the Mattole soils and do not exhibit argillic horizon development but are instead characterized by greater accumulation of SOC across all depths sampled. Overall, our results illustrate how the interaction of climate (i.e., moisture) and time may shape the trajectory of soil development and the dynamics of SOC storage and preservation.
影响因子：
64.8
作者：
Hemingway, Jordon D.;Rothman, Daniel H.;Galy, Valier V.
通讯作者：
Galy, Valier V.