In:
Soil Science Society of America Journal, Wiley, Vol. 56, No. 3 ( 1992-05), p. 733-736
Abstract:
A simple field method for measuring the soil's effectively mobile water fraction during near‐saturated flow is presented. Initial charging of the immobile fraction θ im is achieved by first wetting the soil with a disk permeameter until steady conditions prevail. The disk is then removed and rapidly replaced, but now filled with a tracer solution. Subsequently after a period of infiltration with tracer (0.1 M KBr), the soil underneath is sampled. The ratio of the measured to applied concentration, c */ c m , in the samples will be the fraction of the soil's water that is effectively mobile. We assume that the antecedent tracer concentration is zero, and that the mobile fraction, θ m , is at concentration c m . Disk permeameters, set at the slightly unsaturated potential head ψ o = −20 mm, wetted Manawatu fine sandy loam to a water content of θ o = 0.414 m 3 m −3 . From analysis of the tracer concentrations measured under the disk, we deduced θ m to be just 0.203. This semimobility was in accord with the observed depthwise penetration of tracer, as well as other measures of mobility previously found by others from longer term leaching studies carried out nearby.
Type of Medium:
Online Resource
ISSN:
0361-5995
,
1435-0661
DOI:
10.2136/sssaj1992.03615995005600030010x
Language:
English
Publisher:
Wiley
Publication Date:
1992
detail.hit.zdb_id:
241415-6
detail.hit.zdb_id:
2239747-4
detail.hit.zdb_id:
196788-5
detail.hit.zdb_id:
1481691-X
SSG:
13
SSG:
21
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