Quantitative Analysis of Pedogenic Thresholds and Domains in Volcanic Soils.
Quantitative Analysis of Pedogenic Thresholds and Domains in Volcanic Soils.
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火山土壤成土阈值和域的定量分析。
DOI：
10.1007/s10021-019-00361-1
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Vitousek,PeterM
中科院分区：
文献类型：
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作者：
Bateman,JesseBloom;Chadwick,OliverA;Vitousek,PeterM
成壤阈值描述了土壤性质或过程在环境强迫的微小变化下以突然/非线性方式变化的情况。相比之下，土壤过程域指的是阈值之间的空间，其中土壤特性在广泛的环境强迫下保持不变或逐渐变化。在这里，我们定量测试的存在下的阈值在整个气候梯度的土壤中的土壤性质的模式，从大约20公里的玄武岩基板上的夏威夷岛。从多个土壤性质，我们定量确定了一个阈值在约750毫米/年的水平衡（降水量减去潜在蒸散），划定在这些土壤中的土壤肥力的水平衡上限。根据交换性钙与总钙的比值阈值，我们确定了这些土壤中土壤肥力的水平衡下限为-1000 mm/y;然而，这个阈值是定性描述的，因为它接近气候梯度数据的极限，无法应用统计方法。这两个结果分别代表了第一次使用统计学上严格的方法和所述方法的局限性来确定成壤阈值。比较20-ky土壤上的玄武岩基质的1.2千，7.5千，150千，和4100千的时间-气候矩阵，我们发现，我们的定量分析支持以前定性确定的阈值在从旧基板开发的土壤。我们还确定了20千公斤作为过渡动力学的供应限制在该系统中的土壤中的植物养分。
Pedogenic thresholds describe where soil properties or processes change in an abrupt/nonlinear fashion in response to small changes in environmental forcing. Contrastingly, soil process domains refer to the space between thresholds where soil properties are either unchanged, or change gradually, across a broad range of environmental forcing. Here, we test quantitatively for the presence of thresholds in patterns of soil properties across a climatic gradient on soils developed from about 20-ky-old basaltic substrate on the Island of Hawai’i. From multiple soil properties, we quantitatively identified a threshold at about 750 mm/y of water balance (precipitation minus potential evapotranspiration), delineating the upper water balance boundary of soil fertility in these soils. From the threshold in the ratio of exchangeable Ca to total Ca, we identified the lower water balance boundary of soil fertility in these soils at − 1000 mm/y; however, this threshold was qualitatively described as it lies near the limit of the climate gradient data where the statistical approach cannot be applied. These two results represent the first time that pedogenic thresholds have been identified using statistically rigorous methods and the limitations of said methods, respectively. Comparing the 20-ky soils to soils that developed on basaltic substrates of 1.2 ky, 7.5 ky, 150 ky, and 4100 ky in a time–climate matrix, we found that our quantitative analysis supports previous qualitatively identified thresholds in the soils developed from older substrates. We also identified the 20 ky as the transition from kinetic to supply limitation for plant nutrients in soil in this system.