Prediction of the responsiveness to phosphorus of annual non-irrigated pasture in northern Victoria

Abstract

Field experiments at 43 sites in the Bendigo district of northern Victoria were used to examine the responsiveness of annual non-irrigated pastures to phosphorus application. Of a large range of soil and environmental factors studied, the Olsen soil test (bicarbonate extraction) for phosphorus was the only one that was correlated with pasture response to phosphorus. The relationship for the sum of winter and spring production was: responsiveness b = 0. 12 + 0.73exp(- 0.25 Olsen P); 1 00R2 = 53.6, P< 0.01. Recommendations for the amount of superphosphate to apply to pastures in the Bendigo district are now based on the above relationship, which has been incorporated into a biological model to which economic criteria are applied.