
%0 Journal Article
%A Piper, CS 
%A de, Vries MPC 
%T The residual value of superphosphate on a red-brown earth in South Australia
%J Australian Journal of Agricultural Research
%D 1964/04/01
%V 15
%N 2
%P 234-272
%K 
%R https://doi.org/10.1071/AR9640234
%U https://www.publish.csiro.au/paper/AR9640234 
%X The residual value of superphosphate on a red-brown earth naturally deficient in phosphate has been determined by means of a field experiment. pot trials. and chemical extractions . In a field experiment on a site where 24&frac12; cwt of superphosphate per acre had been previously applied over a period of 23 years, it was found that wheat. in a wheat-barley-fallow rotation. could be grown for 5 years before a clearly defined response developed to superphosphate currently applied at 11 lb (P1) or 22 lb (P2) phosphorus pentoxide (P2O5 ) per acre . Stubble-sown barley showed a response after the first year. 
