Level of zinc in maize seeds and maize growing soils of central Mecha, Amhara National Regional State of Ethiopia
Ethiopia is one of the world countries with reported zinc deficiency or high probability of zinc deficiency. Zinc deficiency is an important soil constraint to crop production, food quality and human health. The aim of this study was to evaluate the zinc concentration of different cultivars of maize seeds and soil samples in central Mecha area using a laboratory analysis to establish whether the roles and effects of zinc in crop productivity and quality in the area could be significant due to plant factors (e.g. cultivar) or changes in soil nutrient zinc concentration or both. Thirty representative soil samples from seven kebeles of the central Mecha and six genotypes of maize grains (Bako Hybrid-540, Bako Hybrid-543, Bako Hybrid-660, Pioneer Hybrid-3253, Melkassa Hybrid-2, and Melkassa Hybrid-4) available in the region for farmers archived by Ethiopian Seed Enterprise (ESE) were collected and analyzed in the laboratory. Zinc levels were determined by FAAS using wet digestion and dilute acid extraction methods. The mean pH (KCl) value of the soils indicated the samples studied are acidic (pH = 4.60). The means and ranges of concentrations of total zinc using strong acids wet digestion and available HCl-extractable zinc in soils (mg Kg-1 DW) were 50.49 mg Kg-1 (44.80 to 65.22 mg Kg-1) and 2.95 mg Kg-1 (1.76 to 4.94 mg Kg-1), respectively. ANOVA analysis revealed significant differences (P < 0.05) between maize varieties in zinc levels. There was significant genetic variability in the level of zinc between the maize cultivars from 16.18 mg Kg-1 for Bako Hybrid-540; 20.08 mg Kg-1 for Bako Hybride-660; 21.08 mg Kg-1 for Pioneer Hybrid-3253; 23.26 mg Kg-1 for Bako Hybrid-543; 29.38 mg Kg-1 for Melkassa-2 to 32.52 mg kg-1 for Melkassa-4. Chemical analysis of composite soil samples indicated that inherent zinc level was on the borderline sufficiency to support good crop growth for now, however; the variations in the level of zinc among the different maize cultivars should be significant in limiting high and quality yield for consumption. Adequate zinc in soils
and high zinc concentrations in seeds ensure agronomic and nutritional benefits resulting in high yield and nutritional quality crops.
Keywords: Crops, Micronutrients, Zinc deficiency, Soil acidity, Ethiopia