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Soil Phosphorus Desorption Kinetics and Its Relationship with Plant Growth
Author(s) -
Raven K. P.,
Hossner L. R.
Publication year - 1994
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/sssaj1994.03615995005800020026x
Subject(s) - desorption , udic moisture regime , chemistry , soil water , phosphorus , environmental chemistry , cation exchange capacity , extraction (chemistry) , adsorption , zoology , soil science , chromatography , environmental science , loam , biology , organic chemistry
The kinetics of P desorption in soils is important to consider from a plant nutrition perspective. This study was designed to compare the ability of several equations to describe P desorption kinetics from soils and to relate the information derived from desorption kinetic curves to plant growth and P uptake. Samples of five soils (Psammentic Paleudult, Typic Calciustoll, Udic Pellustert, Vertic Albaqualf, and Aridic Calciustoll) were treated with five P levels (0, 25, 50 75, and 100 mg kg −1 ) and incubated at field capacity and 24 °C for 31 d. Phosphorus desorption kinetic data for each treatment were generated by equilibrating suspensions of the incubated soil samples with mesh bags containing HCO − 3 ‐saturated anion‐exchange resin for periods up to 96 h. Desorbed P was then determined by extraction of resin P with 0.5 M NaC1. Initial (after 0.25 h) and final (after 72 h) amounts of desorbed P and desorption rates were determined. The kinetic data were best described by the expanded form of the Elovich equation. The initial and final amounts of desorbed P were closely related to relative plant growth and P uptake. The final desorbed soil P was the best soil P availability index. Soil P desorption rates generally had soil‐specific relationships with growth of corn ( Zea mays L.) and P uptake and did not seem to limit the P nutrition of plants. The parameters of the expanded Elovich equation were not satisfactory indicators of the P‐supplying capacity of the soil.