
%0 Journal Article
%A Burkitt, L. L. 
%A Gourley, C. J. P. 
%A Sale, P. W. G. 
%A Uren, N. C. 
%A Hannah, M. C. 
%T Factors affecting the change in extractable phosphorus following the application of phosphatic fertiliser on pasture soils in southern Victoria
%J Soil Research
%D 2001/07/05
%V 39
%N 4
%P 759-771
%K buffering, sorption, Olsen, Colwell, single superphosphate, triple superphosphate, lime.
%R https://doi.org/10.1071/SR00069
%U https://www.publish.csiro.au/paper/SR00069 
%X Nine pasture soils from high rainfall zones of southern Victoria were analysed for a range of chemical and physical properties before receiving a single application of P fertiliser in the form of triple superphosphate (TSP), single superphosphate (SSP), or TSP and lime (5 t/ha) at amounts ranging from 0 to 280 kg P/ha. Soils were analysed for bicarbonate-extractable P concentration, using both the Olsen P and Colwell P methods, 6 and 12 months after fertiliser application. A strong positive linear relationship existed at all sites between the amount of P applied and both the Olsen P and Colwell P concentrations. The slopes of these relationships measured the change in extractable P concentration (&#916; EP) per unit of P applied, whilst the inverse of the &#916;EP value indicated the amount of P fertiliser required above maintenance to increase the extractable P concentration by 1 mg/kg. These values ranged from 5 to 15 kg P/ha, depending on soil type. The &#916;EP measured by the Olsen (&#916; EP Olsen ) method was closely related to selected soil properties and P sorption measures, whilst the &#916;EPColwell values were also closely related to selected soil properties and P sorption measures, but only when one particular site, an acidic sand, with a high organic carbon content was excluded from the analysis. In general, simple, direct measures of soil P sorption could allow the estimation of &#916;EP values on different soil types. The application of P in the form of SSP resulted in a trend for higher &#916;EP values than occurred with TSP. This difference was significant on 3 sites (P &#60; 0.05), but depended on the method of extraction and the time after fertiliser application. The application of lime significantly (P &#60; 0.001) increased soil pH (H2 O and CaCl 2 ) and decreased the concentration of exchangeable Al, 6 months after treatments were applied, but generally had little impact on &#916;EP values. 
