Pedosphere 21(6): 719--729, 2011
ISSN 1002-0160/CN 32-1315/P
©2011 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Grass cover influences hydrophysical parameters and heterogeneity of water flow in a sandy soil |
L. LICHNER1 , D. J. ELDRIDGE2, K. SCHACHT3, N. ZHUKOVA4, L. HOLKO1, M.ŠÍR5 and J. PECHO6 |
1 Institute of Hydrology, Slovak Academy of Sciences, Racianska 75, 83102 Bratislava (Slovakia);
2 Department of Environment Climate Change and Water, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052 (Australia);
3 Geography Department, Ruhr-University Bochum, Universitaetsstrasse 150, 44801 Bochum (Germany);
4 M.Nodia Institute of Geophysics, 1 Alexidze str., 0193 Tbilisi (Georgia);
5 Institute of Hydrodynamics, Academy of Sciences of the Czech Republic, Pod Patankou 30/5, 16612 Prague (Czech Republic);
6 Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic, 1401 Bocni II, 14131 Prague (Czech Republic) |
| ABSTRACT |
| Vegetation cover has a major effect on water flow in soils.Two sites,separated by distance of about 50 m,were selected to quantify the influence of grass cover on hydrophysical parameters and heterogeneity of water flow in a sandy soil emerging during a heavy rain following a long hot,dry period.A control soil (pure sand) with limited impact of vegetation or organic matter was obtained by sampling at 50 cm depth beneath a glade area,and a grassland soil was covered in a 10 cm thick humic layer and colonised by grasses.The persistence of water repellency was measured using the water drop penetration time test,sorptivity and unsaturated hydraulic conductivity using a mini disk infiltrometer, and saturated hydraulic conductivity using a double-ring infiltrometer.Dye tracer experiments were used to assess the heterogeneity of water flow,and both the modified method for estimating effective cross section and an original method for assessing the degree of preferential flow were used to quantify this heterogeneity from the images of dyed soil profiles.Most hydrophysical parameters were substantially different between the two surfaces.The grassland soil had an index of water repellency about 10 times that of pure sand and the persistence of water repellency almost 350 times that of pure sand. Water and ethanol sorptivities in the grassland soil were 7% and 43%,respectively,of those of the pure sand.Hydraulic conductivity and saturated hydraulic conductivities in the grassland soil were 5% and 16%of those of the pure sand, respectively.Dye tracer experiments revealed a stable flow with"air-draining"condition in pure sand and well-developed preferential flow in grassland soil,corresponding to individual grass tussocks and small micro-depressions.The grassland soil was substantially more water repellent and had 3 times the degree of preferential flow compared to pure sand.The results of this study reinforce our view that the consequences of any change in climate,which will ultimately influence hydrology,will be markedly different between grasslands and bare soils. |
| Key Words: dye tracing, grassland soil, hydrophobicity, infiltration, preferential flow |
| Citation: Lichner, L., Eldridge, D. J., Schacht, K., Zhukova, N., Holko, L., ŠÍr, M. and Pecho, J. 2011. Grass cover influences hydrophysical parameters and heterogeneity of water flow in a sandy soil. Pedosphere. 21(6): 719-729. |
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