ISSN:
1365-2389
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
The purpose of the present study was to compare two methods for estimating the hydraulic conductivity near saturation with disc permeameters, and to identify their merits when studying runoff on sloping land. The soil's hydraulic conductivity (K) was measured with disc permeameters at a sequence of nominal pressures (ψ) in three blocks with average slope gradients of 11.0% (two occasions), 21.5% (two occasions) and 29.3% (one occasion), respectively, within a sloping area, 40 m wide and 100 m long. Two different methods were used. In the first, the split-location method, the permeameter was moved to an adjacent spot after measurement at each applied ψ. The estimate of K(ψ) was based on measured sorptivity, steady-state volumetric flow, initial volumetric water content and the volumetric water content at the applied ψ. In the second method, the one-location method, the permeameter was not moved during the measurements at each sequence of applied ψ and the estimate of K(ψ) was based only on steady-state volumetric flow and piece-wise application of the exponential relation between K and ψ. The latter method generally gave smaller estimates of K than the former on the gentle slopes. These differences were smaller or negligible on steeper slopes. The slope gradient and the conditions in the uppermost soil layers had a definite influence on the values of K obtained. The one-location method is recommended in studies in which disturbance of the soil surface must be kept to a minimum, as is the case in experimental plots.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1365-2389.2000.00281.x
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