Effects of phosphate buffering on the extraction of labile phosphate by plants and by soil tests

Abstract

In a glasshouse experiment on 24 calcareous soils, the uptake of isotopically exchangeable phosphorus by ryegrass was negatively related to the phosphate buffer capacity. The corresponding effect of buffering on the extraction of exchangeable phosphorus by sodium bicarbonate was almost identical. In four different soil tests, the greater the effect of buffering on extraction, the higher was the correlation between the soil test and phosphorus uptake by the ryegrass.