Effect of Zinc Application Rates on Manihot esculenta Yield Grown in Coastal Plain Sand Soils of Nigeria

Two experiments at greenhouse and field scale were undertaken to determine the optimum rate of zinc sulphate for cassava tuber production in coastal plain sand derived soil of southeastern Nigeria.  The results of greenhouse experiment showed that the application of Zn into the soils significantly (P < 0.05) increased cassava dry matter production, concentration, uptake and tuber yields. The estimated optimum rates for Zn under greenhouse environments were established at 7 kg Zn ha⁻¹ for Zn uptake of cassava shoots. Also established were optimum Zn levels of 12, 13 and 15 kg Zn ha⁻¹, and maximum cassava tuber yields, respectively. In conclusion, it is recommended that application of zinc sulphate at a rate of 15 kg Zn ha⁻¹ is essential for cassava production (t ha^-1) at coastal plain sand derived soils of southeast agro-ecological zone of Nigeria.