Organic phosphorus content in soil samples

Abstract

The objective of this laboratory investigation was to estimate the total organic phosphorus content, and labile organic phosphorus fraction of samples taken from the surface layer of soils of different taxonomic classes. The study was a completely randomized design with the treatments consisted of 17 soil samples. The content of total organic phosphorus varied from 7 to 272 mg/kg of soil. The labile organic phosphorus varied from 6 to 35 mg/kg of soil, being much greater than the labile inorganic phosphorus, and on average corresponding to 26% of the total organic P in the soil. Analysis revealed that total organic P was correlated with total P and C in ultisols and total P, Fe₂O₃ and clay content in oxisols. Thus, for both soil classes, the labile organic P was intimately related to the available P, indicating the potential contribution of this fraction to the availability of phosphorus in these soils.