Zinc distribution in Zimbabwean soils and its relationship with other soil factors

Abstract

Abstract The distribution of zinc in some major Zimbabwean soils was studied using 120 profiles taken from 22 different locations. The total zinc status (TL‐Zn) of the horizons of soils studied was low (8 ppm), and the range was narrow (3.7 to 16.3 ppm). The residual zinc (RS‐Zn) fraction was about 65 percent of the total zinc found in the soils, while 15 percent was organically bound zinc (OG‐Zn), 14 percent was available zinc (MG‐Zn), and 6 percent was zinc associated with hydrous metal oxides (OX‐Zn). The total zinc status of the soils was related to parent material. Generally, texture had a significant effect on zinc distribution with heavier textured soils having more zinc in most fractions than the lighter textured soils. A decrease in zinc down the profile was observed for available, residual, and total zinc. If cropped intensively, 32 per cent of the soils with less than 1 ppm available zinc have the potential for zinc deficiency. Multiple stepwise regression analysis showed that organic matter, s...