
%0 Journal Article
%A Batten, G. D. 
%A Fettell, N. A. 
%A Mead, J. A. 
%A Khan, M. A. 
%T Effect of sowing date on the uptake and utilisation of phosphorus by wheat (cv. Osprey) grown in central New South Wales
%J Australian Journal of Experimental Agriculture
%D 1999/05/17
%V 39
%N 2
%P 161-170
%K 
%R https://doi.org/10.1071/EA97104
%U https://www.publish.csiro.au/paper/EA97104 
%X Experiments were sown at Cowra and Condobolin to determine the effect of sowing time (April&#8211;June) on the response to and utilisation of phosphorus by the wheat cultivar Osprey which requires vernalisation. Crops sown in April needed only 0&#8211;2 kg/ha of applied phosphorus to achieve 90% of the maximum yield for the site. This contrasts with crops sown at the traditional sowing time in May&#8211;June which needed from 11.5 kg P/ha, on a site with a moderate soil phosphorus status, to 36 kg P/ha, on a site with a very low soil phosphorus status, to produce 90% of the site maximum yield. Crops sown in April had higher yields and even without applied phosphorus accumulated more phosphorus (kg/ha) than crops sown in June with 40 kg P/ha. Crops sown in April had a lower dry matter harvest index, a lower phosphorus harvest index, produced less grain per kilogram of phosphorus in the shoots at maturity, and had a higher grain phosphorus concentration than crops sown in June. Grain protein was not affected by sowing date or the amount of phosphorus applied at sowing. At 90% of maximum dry matter yield shoots had 0.14&#8211;0.20% phosphorus at growth stage 30. The critical concentration of phosphorus in grain at 90% maximum grain yield increased with yield from 0.19 to 0.25% phosphorus. Farmers who sow wheat in April can achieve optimum yields with lower inputs of fertiliser phosphorus. However, this benefit will be offset by a lower phosphorus-use efficiency and more rapid depletion of phosphorus reserves from the soil. 
