Effect of spatial distribution and soil volume fertilized on recovery of phosphorus fertilizer by wheat in a pot experiment

Labelled Ca(H₂PO₄)₂ · H₂O was added to two soils (an Oxisol and a vertisol) at two rates, both as a point source and completely dispersed through the soil. The point source treatments included two spatial distributions at each of two percentages of soil volume fertilized. Total and fertilizer phosphorus uptake by wheat (Triticum aestivum) grown for 42 days were determined in a glasshouse experiment. Uptake of fertilizer phosphorus was not affected by spatial distribution, but declined in the Oxisol as percentage soil volume fertilized increased at the low application rate. The implications of these results in terms of the effects of cultivation on fertilizer availability are briefly discussed.