Controls of surface soil moisture spatial patterns and their temporal stability in a semi‐arid steppe
Controls of surface soil moisture spatial patterns and their temporal stability in a semi‐arid steppe
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DOI：
10.1002/hyp.7665
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发表时间：
2010-08
影响因子：
3.2
通讯作者：
Y. Zhao;S. Peth;X. Y. Wang;H. Lin;R. Horn
中科院分区：
文献类型：
--
作者：
Y. Zhao;S. Peth;X. Y. Wang;H. Lin;R. Horn
土壤水分空间格局的时间稳定性对优化水土管理和有效的田间监测具有重要意义。以中国半干旱草原为研究对象，研究了不同放牧强度下4个样地105 m × 135 m土壤水分空间格局的时间稳定性。我们还研究了是否可以从致病因素（即土壤、植被和地形）中确定时间稳定的位置。在每个样地，从2004年到2006年，每隔两周在每个网格中使用100个点测量表层土壤湿度（0-6 cm）。在相同的网格点上确定了土壤湿度的可能控制因素，包括土壤质地、有机碳、容重、植被覆盖度和地形指数。结果表明，在3年监测期内，土壤水分的空间格局较为稳定。湿润条件下的土壤水分（平均体积含水量bbb20）%) was more stable than that under dry ($\bar{\theta}_{j, t} < 10\%$) or moist ($\def\endash{\hbox{--}} \bar{\theta}_{j, t} = 10\endash 20\%$) conditions. The best representative point for the whole field identified in each plot was accurate in representing the field mean moisture over time (R2 ≥ 0·97; p < 0·0001). The degree of temporal persistence varied with grazing intensity, which was partly related to grazing‐induced differences in soil and vegetation properties. The correlation analysis showed that soil properties, and to a lesser extent vegetation and topographic properties, were important in controlling the temporal stability of soil moisture spatial patterns in this relatively flat grassland. Response surface regression analysis was used to quantitatively identify representative monitoring locations a priori from available soil‐plant parameters. This allows appropriate selection of monitoring locations and enhances efficiency in managing soil and water resources in semi‐arid environments. Copyright © 2010 John Wiley & Sons, Ltd.
Temporal stability of soil moisture spatial patterns has important implications for optimal soil and water management and effective field monitoring. The aim of this study was to investigate the temporal stability of soil moisture spatial patterns over four plots of 105 m × 135 m in grid size with different grazing intensities in a semi‐arid steppe in China. We also examined whether a time‐stable location can be identified from causative factors (i.e. soil, vegetation, and topography). At each plot, surface soil moisture (0–6 cm) was measured about biweekly from 2004 to 2006 using 100 points in each grid. Possible controls of soil moisture, including soil texture, organic carbon, bulk density, vegetation coverage, and topographic indices, were determined at the same grid points. The results showed that the spatial patterns of soil moisture were considerably stable over the 3‐y monitoring period. Soil moisture under wet conditions (averaged volumetric moisture contents > 20%) was more stable than that under dry ($\bar{\theta}_{j, t} < 10\%$) or moist ($\def\endash{\hbox{--}} \bar{\theta}_{j, t} = 10\endash 20\%$) conditions. The best representative point for the whole field identified in each plot was accurate in representing the field mean moisture over time (R2 ≥ 0·97; p < 0·0001). The degree of temporal persistence varied with grazing intensity, which was partly related to grazing‐induced differences in soil and vegetation properties. The correlation analysis showed that soil properties, and to a lesser extent vegetation and topographic properties, were important in controlling the temporal stability of soil moisture spatial patterns in this relatively flat grassland. Response surface regression analysis was used to quantitatively identify representative monitoring locations a priori from available soil‐plant parameters. This allows appropriate selection of monitoring locations and enhances efficiency in managing soil and water resources in semi‐arid environments. Copyright © 2010 John Wiley & Sons, Ltd.