Kh.Zoljargal-MSSJ_19.pdf

Phosphorus is an essential nutrient in plants required for root establishment. There are many methods for the extraction of available forms; however the choice is dependent on several factors among them soil pH. Forty nine samples were collected from three different sites from Bayankhongor, Orkhon aimag and Ulaanbaatar city. The samples were air dried, sieved, under 2 mm sieve and stored in sample bags for subsequent analysis. Phosphorus extractions of were carried out using a basic extractants. The extracts of Machigin and Olsen were measured colorimetrically by the hydrazine method and ascorbic acid method at 630 nm and 880 nm wavelength respectively. The soils had a pH range of between 6.98-7.80; phosphorus, 3.70-71.4 mg P/ kg by Machigin and 2.22-21.37 mg P/kg by Olsen. The methods were linearly correlated (r=0.82).