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Potassium Removed from Some Southern Brazilian Soils by Exhaustive Cropping and Chemical Extraction Methods
Author(s) -
Oliveira V.,
Ludwick A. E.,
Beatty M. T.
Publication year - 1971
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/sssaj1971.03615995003500050037x
Subject(s) - inceptisol , alfisol , mollisol , ultisol , lolium perenne , chemistry , oxisol , soil water , entisol , agronomy , lolium , perennial plant , poaceae , environmental science , soil science , biology
Soils from the orders Alfisol, Inceptisol, Mollisol, Ultisol, and Oxisol contained exchangeable K (neutral 1 N NH 4 OAc) and boiling 1 N HNO 3 extractable K varying from 31 to 358 ppm and 62 to 652 ppm, respectively. Total K varied from 1,780 to 14,200 ppm. Quantities absorbed from each soil by 7 cuttings of perennial ryegrass ( Lolium perenne ) in the greenhouse ranged up to 13 times that of exchangeable K and up to 5 times that of HNO 3 ‐extractable K. Total plant uptake represented 3.5 to 29.7% of total soil K. In no soil did K become limiting in the first four cuttings. However, except for the Mollisols, uptake decreased abruptly in the later cuttings, indicating very little “slowly” available K. Even though exchangeable K and K removed by strong acids were highly correlated with plant uptake ( r = 0.744** to 0.881**), all extractants greatly underestimated actual plant‐available K under intensive cropping. Total soil K did not significantly correlate with plant uptake ( r = 0.211).