
%0 Journal Article
%A Fleming, N. K. 
%A Bolland, M. D. A. 
%A Gilbert, M. A. 
%T Effect of reactive phosphate rocks and water-soluble phosphorus fertilisers on extractable phosphorus concentrations in soil
%J Australian Journal of Experimental Agriculture
%D 1998/02/27
%V 37
%N 8
%P 1009-1017
%K 
%R https://doi.org/10.1071/EA96116
%U https://www.publish.csiro.au/paper/EA96116 
%X Summary. Soil samples were collected each year from all plots at all sites in the National Reactive Phosphate Rock Project and analysed for bicarbonate-soluble phosphorus (P) using the Colwell procedure (soil test P). The relationship between soil test P and the level of P applied was adequately described by a linear equation. The slope coefficient of this equation provides a measure of the extractability of P from soil treated with a particular fertiliser and has been termed the &#8216;extractability&#8217; for that particular fertiliser at that site. Extractability values were used to estimate phosphate rock effectiveness; this was done by dividing the extractability for each phosphate rock by the extractability of the reference water-soluble P fertiliser to provide a relative soil extractability (RSE). There was a good agreement between the RSE for a phosphate rock and its substitution value for water-soluble P fertiliser, which is a measure of fertiliser effectiveness based on pasture yield. Estimates of fertiliser effectiveness, based on increases in soil test P values, also agreed with estimates based on pasture yield with respect to the ranking of different P fertilisers, and the ranking of phosphate rocks in order of their reactivity. Simple and multiple linear regression analyses were used to identify relationships between a range of soil properties and extractability values across sites, but no relationships were found. 
