Use of 31P-NMR to study the forms of phosphorus in peat soils

Abstract

31P-NMR has been used to characterise the major forms of organic and inorganic phosphorus in soil derived alkali extracts and humic acids. Blanket peat, which had been under different fertilisation treatments for 10 years was compared with an agricultural mineral soil. In the mineral soil the phosphorus was shown to be in the form of inorganic orthophosphate and phosphate monoesters whereas the peat soil also contained phosphate diesters and other inorganic forms of phosphorus. Changes in various phosphorus pools in the peat soils were shown to correlate with differences in fertilisation regime and land management practice. Fertilisation with superphosphate increased phosphate monoester content in the peat, although vegetation type appeared to have greater impact on the phosphate monoester concentration. The degree of microbial activity, as indicated by the presence of polyphosphates and absence of phosphonates, correlated positively with vegetational improvement and fertilisation of the peat soils.