Open Access Repository

A simple phosphorus buffering index for Australian soils


Downloads per month over past year

Burkitt, LL, Moody, PW, Gourley, CJP and Hannah, MC 2002 , 'A simple phosphorus buffering index for Australian soils' , Australian Journal of Soil Research, vol. 40 , pp. 497-513 , doi: 10.1071/SR01050.

[img] PDF
Burkitt_et_al_2...pdf | Document not available for request/download
Full text restricted
Available under University of Tasmania Standard License.


Soil phosphorus (P) buffering capacity (PBC) is an important soil property that influences the amount of P fertiliser available for plant uptake. However, current methods of determining PBC are time-consuming and uneconomic in most commercial soil testing programs. The current study examined simpler methods of measuring the PBC of a wide range of Australian soils. Phosphorus sorption and extractable P data from 290 soils (initial data set) were collated to define the range of PBC values of Australian agricultural soils. Independently, detailed chemical and physical analyses were undertaken on a second set of 90 agricultural soils (principal data set), which were selected to represent the range of soil properties measured on the initial data set.

Relationships between PBC O&S (Ozanne and Shaw 1968) values (P sorbed between solution P concentrations of 0.25 and 0.35 mg P/L) and 11 different single-point P sorption indices and selected soil properties were examined for the principal data set. Whilst relationships between PBC O&S values and selected soil properties such as oxalate-extractable iron and aluminium, and clay content, were generally poor, strong relationships existed between all of the single-point P sorption indices and PBCO&S. Results suggest that PBCO&S values were most closely related to the P buffering indices (PBI+ColP and PBI+OlsP) when a single addition of 1000 mg P/kg was added to soil and either the Colwell or 4.59 Olsen extractable P were added to the amount of P sorbed:

PBI+ColP = (Ps + Colwell P)/c0.41

PBI+OlsP = (Ps + 4.59 Olsen P)/c0.41

where Ps is the amount of P sorbed (mg P/kg) from a single addition of 1000 mg P/kg, and c is the resulting solution P concentration (mg P/L).

This index provides a simple and accurate method for estimating PBC, a fundamental soil property that influences the P fertiliser requirements of different soil types.

Item Type: Article
Authors/Creators:Burkitt, LL and Moody, PW and Gourley, CJP and Hannah, MC
Keywords: phosphorus sorption capacity, single-point phosphorus sorption index, phosphorus retention index, soil properties, Colwell phosphorus, Olsen phosphorus.
Journal or Publication Title: Australian Journal of Soil Research
DOI / ID Number: 10.1071/SR01050
Item Statistics: View statistics for this item

Actions (login required)

Item Control Page Item Control Page