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Soil Moisture Effects on Potassium Release Observed on Drying Soils with Organic Additives
Author(s) -
Bates T. E.,
Scott A. D.
Publication year - 1965
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/sssaj1965.03615995002900060024x
Subject(s) - subsoil , potassium , moisture , chemistry , water content , boiling , soil water , desiccation , environmental chemistry , environmental science , soil science , botany , organic chemistry , geotechnical engineering , biology , engineering
A release of 223 ppm K occurred when Marshall subsoil samples were heated for 40 days in a drying oven at 110C. Most of this release can be attributed to the desiccation attained, not the heat, because similar heat treatments without drying increased the exchangeable K level by only 33 ppm. The release of K associated with drying was entirely eliminated by adding organic compounds to the soil samples before they were dried. To attain this control of K release, however, it was necessary to dry the soil under conditions that ensured the presence of the organic compounds throughout the drying period. Otherwise, the effect of organic additives varied with the initial moisture level of the soil and the relative rates at which the water and organic additives were lost. Single additions of compounds with high boiling points were particularly effective in controlling K release, but even ethanol (boiling point 78C) prevented K release when it was maintained in the soil while the soil moisture was removed. A practical method of controlling the release of K associated with drying involves the addition of 20 mmoles dextrose to 10 g soil. This treatment eliminates K release despite the presence of large amounts of water or the use of different drying rates.