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A Device for Rapid Field Measurement of A Soil's Water Transmission Rate
Author(s) -
Fletcher Peter W.
Publication year - 1957
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1957.03615995002100050026x
Subject(s) - citation , library science , field (mathematics) , columbia university , computer science , sociology , media studies , mathematics , pure mathematics
Many soil physicists have considered that some measure of the permeability of soil should provide a quantitative expression of its structure. Both air and water have been used as the fluid. Being a porous medium, the soil offers resistance to the passage of the fluid, depending upon the size, shape, and continuity of the pores. A soil with many large circular, continuous pores offers least resistance, and is classed as very permeable. Conversely, a soil with small, occluded, discontinuous pores approaches impermeability. An extremely wide range of permeability values has been reported for various surface soil-cover and land-use complexes, as well as for the several horizons in a mature soil profile. This sensitivity is doubtless influenced as much (or more) by the shape and continuity of the large pores as it is by their volume alone. Certainly, the permeability value depends upon the integrated effect of all three pore features, and not necessarily on one alone. For example, figure 1 shows a scatter relationship between water transmission rate and volume of large pores (as determined at 60-cm. water tension or, pF 1.78). With 15% by volume of large pores, a coarse mull may have a