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Limitations in the Use of Electrical Resistance Soil Moisture Units 1
Author(s) -
Weaver H. A.,
Jamison V. C.
Publication year - 1951
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1951.00021962004300120004x
Subject(s) - citation , resistance (ecology) , computer science , agronomy , library science , biology
' I 'HE gypsum block electrical soil moisture instruJ. merit of Bouyoucos and Mick (2) has proved useful for in situ moisture or tension measurements. The units however tend to deteriorate rapidly in poorly drained soils, and their electrical resistance in such soils changes little with variation in moisture tension. The nylon electrical resistance unit of Bouyoucos (1) and the fiberglas unit of Colman and Hendrix (3) give some promise of overcoming these difficulties. The units are sensitive to changes in moisture tension in the wet range and appear somewhat more durable than gypsum units in very wet soils. The fabric units are an improvement over the gypsum block in that the conductive path is independent of the soil surrounding the unit. The fiberglas unit is equipped with a built-in electrical thermal unit for measuring soil temperature. This study was designed to test the reproducibility of fabric units for moisture tension measurements under controlled conditions, to determine the effect of varying electrolyte concentration on their resistance, and to note mechanical features which might limit or extend their usefulness. The tests were performed on commercial samples of the nylon and fiberglas units.