Effect of pH,and phosphorus and organic matter contents on zinc availability and distribution in two Zimbabwean soils

Abstract

Laboratory studies to assess the effects of pH, and phosphorus (P) and organic matter contents on zinc (Zn) distribution in various soil fractions were conducted. Soils were incubated with different levels of lime, P fertilization, and two types of added organic materials. Phosphorus and pH were found to influence Zn distribution in the different soil fractions. Increase in pH and P decreased available and organic Zn and increased unavailable forms. Where fresh Zn was applied, a greater proportion of Zn was retained in the available and organically‐bound Zn forms. Application of maize stover and cow manure had a temporal effect of reducing available zinc in both the Chiota and Gwebi soils. The organic Zn and other unavailable forms of Zn increased showing that Zn was being immobilised. The immobilization was a relatively rapid process occurring in the first two weeks. The release of Zn which had been immobilised increased with time of incubation.