Zinc availability of two wheat cultivars in soil amended with organic and inorganic Zn sources

Abstract

The nutrients and organic matter in organic amendments provide a valuable resource to agriculture, forestry and remediation of degraded lands. The objective of this research was to investigate the effects of two wheat cultivars (cv. Backcross and Alvand) on zinc (Zn) uptake in a loamy soil amended with organic and inorganic Zn sources. A factorial experiment using randomized complete blocks was used in three replications. A Zn enriched cow manure (800 mg Zn kg^-1) was applied to the soil at three rates of 25 (V₁), 50 (V₂), and 100 Mg ha^-1 (V₃). To compare the effects of organic and inorganic sources, similar rates of Zn as zinc sulphate (ZnSO₄) were also applied (Zn₁, Zn₂ and Zn₃, respectively). An untreated soil sample was considered as control soil (V₀). In general, cultivation of wheat plant (cv. Backcross) resulted in a lower Zn uptake relative to the Alvand cultivar. However, the plants Zn concentration of both cultivars depended on the rate and type of the applied manure (organic or inorganic sources). Both cultivars showed that plants grown in soil treated with ZnSO₄ accumulated significantly greater Zn in their root tissue compared to those grown in soil treated with cow manure. A significant increase in the shoot, spike and root Zn concentration was observed as the loading rate of cow manure increased. The results of this experiment point to the fact that the source of fertilizer, type of the plant and the loading rate of Zn are important factors in determining Zn phytoavailability.

Key words: Heavy metal, cow manure, ZnSO₄, phytoavailability, seed yield.