Premium
Potassium Supply Characteristics of Thirty‐three Soils as Influenced by Seven Rates of Potassium
Author(s) -
Kovar J. L.,
Barber S. A.
Publication year - 1990
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/sssaj1990.03615995005400050026x
Subject(s) - soil water , potassium , chemistry , fertilizer , nitrogen , analytical chemistry (journal) , a value , phosphorus , mineralogy , soil science , environmental chemistry , geology , organic chemistry
Limited information is available on the effect of applications of multielement fertilizer materials on the concurrent changes in K l (soil‐solution K) and K s (exchangeable K). The objectives of this research were to: (i) investigate the relative increases in both K l and K s after addition of graded amounts of a 3‐4‐7.5 solution fertilizer; and (ii) determine if the changes in K l and K s with fertilizer additions were related to some measurable physical or chemical property of the soil. Thirty‐three surface soils were equilibrated moist for 3 wk after addition of 0, 21, 42, 104, 208, 415, and 1245 mg K per kg of soil. High rates of application were used because they occur when the same total amount of K is placed in a small fraction of soil, e.g., band application. Values of K l were determined from water‐displaced soil solution. Values of K s were obtained from K extracted with 1.0 M NH 4 OAc at pH 7.0 minus θK l , where θ is the volumetric water content g −1 of sample. The increase in K l with K addition was described by K l = ax c + d , where x is the amount of added K and a and d are regression constants. Values of c , the curvilinearity coefficient, varied from 1.00 (linear) to 1.59. The increase in K s with K addition was described by K s = g + hx . The value g represents the amount of exchangeable K in the untreated soil. Values of h , the slope, varied from 0.42 to 1.13. The coefficients describing the relation of both K l and K s to added K were not correlated with any of the measured soil properties. There was no significant correlation between c and h . Characterization of the changes in K l and K s after addition of K gives information useful for determining the effectiveness of K placement.