Mobilization of noneachangeable K in soils
2000
Raychaudhuri, M. (ICAR Research Complex for NEH Region, Lamphelpat, (India)) | Sanyal, S.K. (Bidhan Chandra Krishi Viswavidyalaya, Nadia (India). Dept. of Agricultural Chemistry and Soil Science)
Detailed characteristics of the nonexchangeable K fraction of soils of different orders, namely, Entisol, &fiso.l, Mollisol and Inceptisol were studied. The non-exchangeable K reserves have been categonzed mto step K and constant rate K. The threshold level of K release from the intermediate K in terms of activity ratio, K concentration and exchangeable K has also been determined. The mineralogical composition of the soils varied widely. The amounts of nonexchangeable K and step K were significantly correlated with the illitic fraction content and the percentage clay present in the soil. The CR-K and specifically held K were also significantly correlated with the percentage of illitic minerals present in the clay fraction. The threshold values in tenns of K concentration and activity ratio changed considerably for all the soils as the electrolyte concentration decreased from 0.01 to 0.002 M. Soil samples studied released intermediate K at a very low activity ratio except Inceptisol.
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