|
|
Article: The systematic effect of soil P buffer capacity on Colwell soil P test v. plant response calibration exists only when field experiments are adjacent.
- Article from:
- Australian Journal of Soil Research
- Article date:
- December 1, 2004
- Author:
CopyrightCOPYRIGHT 2004 CSIRO Publishing. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
|
Introduction
The Colwell (1963) soil test procedure, a modification of the original sodium bicarbonate soil test procedure (Olsen et al. 1954), is the soil phosphorus (P) test used in much of Australia. Colwell soil test P values are strongly influenced by the capacity of soil to sorb P (Barrow and Shaw 1976). In Australia the capacity of soil to sorb P is frequently measured using the P buffer capacity (PBC) of Ozanne and Shaw (1968), which is the amount of P sorbed by soil between equlibrium concentrations of 0.25 and 0.35 mg P/L in solution.
Helyar and Spencer (1977) showed that the PBC of the soil affected the Colwell soil P test calibration such ...