Nutrient Availability in Calcareous Soils as Affected by Sulphur and Zinc Application.

Abstract

The effect of S-application on plant availability of nutrients, was studied in two calcareous soils of widely different CaCO3 content and clay/CaCO3. The effect of zinc application to Zn-deficient highly calcareous Dirab soil, was also compared with that of S-application. The experiments were carried out in the greenhouse using 0.5, 1.0 and 1.5% elemental sulphur and 2, 4, 8 ppm Zn as ZnSO4. S-application had no significant effect on dry matter of barley plants and the uptake of N, P, K, Mn and Zn in highly calcareous Dirab loamy sand of low caly/ CaCO3 % ratio, while the uptake of Fe generally increase. On the-other hand, dry matter of barley plants and the uptake of N, K, Fe, Mn and Zn were significantly increased by S- addition to low CaCO3 Qasseem sandy loam of high clay/ CaCO3 ratio. Fe and Mn-uptake were affected most whereas Zn-uptake was least affected by S addition in Qasseem soil. S-application to Zn treated highly calcareous Dirab soil had generally no significant effect on dry matter of barley and the content and uptake of all studied nutrients. Zn-addition to this soil, however, considerably increased dry matter of barley plants and their uptake of N, P, K, Fe, Mn and Zn