Effect of Different Rates of Zinc Sulphate on Wheat Growth and Micronutrient Status in Kano State

Zinc deficiency is a widespread micronutrient constraint in calcareous soils of northern Nigeria, reducing wheat yield and grain nutritional quality, and establishing optimal zinc sulphate rates for irrigated wheat production in Kano State is important for yield and nutritional improvement. This study examined the effect of four zinc sulphate application rates (0, 10, 20, and 30 kg ZnSO4 ha-1) on wheat growth, grain yield, and grain zinc content at the Kano Agricultural and Rural Development Authority demonstration farm, Kano State. A randomised complete block design experiment with three replications was conducted during the 2022-2023 irrigation season using NESSER wheat variety. Plant height, SPAD readings, above-ground biomass at anthesis, grain yield, grain zinc content, and soil available zinc before and after the season were determined. Results showed that 20 kg ZnSO4 ha-1 produced the highest grain yield (3.84 tonnes per hectare) and grain zinc content (38.7 mg kg-1), compared to the control (2.93 t ha-1 and 22.4 mg kg-1). The 30 kg ha-1 rate did not significantly improve yield over 20 kg ha-1. SPAD readings at heading were significantly correlated with final grain yield (r = 0.81, p < 0.05). Pre-season soil available zinc levels below 0.5 mg kg-1 were recorded in 77.8 percent of the experimental plots, confirming widespread deficiency. The study recommends 20 kg ZnSO4 ha-1 as the optimal zinc fertiliser rate for wheat production in zinc-deficient soils of Kano State. Keywords: zinc sulphate, wheat, grain yield, micronutrient, Kano State