Influence of soil parameters on DTPA extractable micronutrients in arid soils

The influence of soil parameters on the DTPA extractable micronutrients in texturally different soils appeared variable. In the three types of soils, among the different soil parameters negative dominating influence of CaCO₃ on the DTPA extractable iron and of soil pH on the DTPA extractable manganese indicated that soil pH and reduction-oxidation status exerts major influence on their availability. The DTPA extractable manganese was also influenced positively in coarse textured soils by organic carbon and free manganese and in fine textured soils by free iron. The DTPA extractable zinc content, in coarse and medium textured soils was negatively influenced respectively by free iron and pH. The DTPA extractable copper in coarse and medium textured soils appeared related with the organic carbon content. The predictabilities of DTPA extractable iron, manganese and copper was much better in the coarse textured soils (34, 66 and 37 per cent) whereas DTPA extractable zinc could be better predicted (26 per cent) only in the fine textured soils.