The determination of labile soil phosphate as influenced by the time of application of labelled phosphate

Summary An experiment was conducted to determine the effect on the L-values of pre-equilibrating P³² with three soil types for 2, 1, and 0 months before sowing ryegrass. Resin and phosphoric acid were used as carriers. Equilibrium was established some twelve weeks after sowing and this time was virtually unaffected by the pre-equilibration treatments. The phosphate source was found to affect both P uptake and L-value; higher uptake and lower L-values were recorded from the resin.