Regional-scale variation and distribution patterns of soil saturated hydraulic conductivities in surface and subsurface layers in the loessial soils of China

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• 作者：Yunqiang Wang^a ; ^b ; ^c ; Ming&rsquo ; an Shao^b ; ^{shaoma@igsnrr.ac.cn} ; Zhipeng Liu^c ; Robert Horton^d
• 关键词：Land use ; Soil texture ; Principal component analysis ; Minimum data set ; Geostatistics ; Soil hydraulic conductivity
• 刊名：Journal of Hydrology
• 出版年：2013
• 出版时间：22 April, 2013
• 年：2013
• 卷：487
• 期：Complete
• 页码：13-23
• 全文大小：1008 K

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Summary

Saturated hydraulic conductivity (K_s) is an important soil property that shows a high degree of spatial heterogeneity. There is a lack of research that investigates and determines K_s at a regional scale, due to the challenges associated with the required intensive sampling. To determine the closely correlated factors affecting K_s at a regional scale and to then generate a regional distribution map of K_s, we selected 382 sampling sites across the Loess Plateau of China (620,000 km²) and collected undisturbed and disturbed soil samples from two soil layers (0-5 and 20-25 cm). We found that both surface K_s and subsurface K_s had log(base 10)-normal distributions, and demonstrated strong spatial variability (CV = 206 % and 135 % , respectively). Surface LogK_s was most closely correlated with LogSand, LogSilt, LogSG (slope gradient), LogSSWC (saturated soil water content), vegetation coverage and land use; while subsurface LogK_s was correlated with LogClay, SSWC, LogSG, LogAltitude, LogGY (growth year) and land use. Geostatistical analysis indicated that semivariograms of surface and subsurface Log K_s could be best fitted by an isotropic exponential model, with effective ranges of 204 km and 428 km, respectively. Distribution maps of K_s produced by kriging indicated a pronounced spatial pattern and demonstrated an obvious spatial depth gradient. The spatial distribution patterns of K_s at a regional scale in the loessial soils of China comprehensively reflected soil hydraulic properties and the combined effects of soil texture, vegetation, topography and human activities.