STATUS OF ORGANIC PHOSPHORUS IN SOME ALBERTA SOILS

Abstract

Two medium-textured profiles, widely separated geographically, were selected at virgin sites within each of the six soil zones of Alberta. Samples from the different horizons were analysed for pH, organic carbon, organic nitrogen, and non-sulphate sulphur. Total organic phosphorus values were obtained by two acid-alkaline extraction procedures (8, 10). The values obtained by the Kaila-Virtanen method (8) were used for the correlation and ratio calculations.The total organic phosphorus content decreased with increasing depth in all profiles. The values for the surface horizons of soils sampled from the Brown, Dark Brown, Thin Black, Black, Dark Grey, and Grey Wooded soil zones were 172, 247, 479, 625, 415, and 500 p.p.m., respectively. In terms of percentage organic phosphorus of total phosphorus, these figures were 34, 36, 47, 51, 42, and 38 per cent, respectively. This trend was found for both methods.The methods were similar in their ability to extract organic phosphorus. However, there was a tendency for the Mehta et al. method (10) to extract more than the Kaila-Virtanen procedure from the surface horizon of the soils from the Thin Black, Black, Dark Grey, and Grey Wooded soil zones. It is further concluded that, for the soils under study, organic phosphorus formed an integral part of the organic matter.