G.B. ROBBINS¹, J.J. BUSHELL¹ and J.F. COMPTON²

¹Queensland Department of Primary Industries "Brian Pasture" Pasture Research Station, Gayndah, Qld. 4625.
²P.O. Box 1143, Bundaberg, Qld. 4670.

Abstract

Plant N, P and S concentrations in grass–legume pasture on a sandy loam were generally lower from biosuper 20 months after application than from the equivalent level of superphosphate. After 37 months, P and S concentrations in herbage treated with biosuper were generally similar to those from equivalent rates of' superphosphate, suggesting a possible increase in the availability of P and S from biosuper over time. It is most likely that the biosuper was simply acting as a mixture of rockphosphate and sulphur, rather than as "biological superphosphate".