FRACTIONATION OF MICRONUTRIENTS IN SELECTED SOILS FROM SAUDI-ARABIA

Fractionation of micronutrients into 5 fractions was carried out on te n selected soils in Saudi Arabia (Tessier et al. 1979). The ranges for different micronutrient fractions were: 0 - 796, 0 - 105, 0 - 75 and 0 - 59942 ug g(-1) for Mn, Zn, Cu and Fe, respectively. The residual f raction constitutes the absolute majority of all fractions and the ord er of the 5 fractions was: Residual > Fe-Mn Oxide bound > CO3 bound > organic bound > exchangeable. The DTPA extractable micronutrients rang ed from 1.56 - 16.30 ug g(-1) for Mn, 0.09 - 2.20 ug g(-1) for Zn, 1.5 1 - 17.7 ug g(-1) for Fe and 0.07 - 2.73 ug g(-1) for Cu extraction of micronutrients with DTP A showed strong relationship with micronutrie nts estimated by using different fractionation schemes. Therefore, it is considered a good estimation for the availability of micronutrients in the studied soils.