Effect of Cu AND Zn On Maize (Zea Mays L.) Yield and Nutrient Uptake in Coastal Plain Sand Derived Soils of Southeastern Nigeria

Abstract

Micronutrients, which are often found to be lacking in coastal plain sand derived soils, can lead to higher crop yields in this area. The use of Cu and Zn as fertilizers could be a variable option to fulfill the demand for these elements and also to increase its contents in maize grains. In this study, laboratory, greenhouse and field studies were undertaken to investigate the status of Cu and Zn and to find out whether the addition of these nutrient elements would increase maize grain yields and yield components and also, remediate their constraints in coastal plain sand derived soil of southeastern Nigeria, for optimization of maize (Zea mays L.) yields. Dry matter yields, plant concentrations, plant uptake, and maize grain yield was used to evaluate the effects of Cu and Zn levels. In both the greenhouse and field experiments, hydrated Cu and Zn sulphate fertilizers were applied to the soils in separate experiments at seven levels (0, 2, 4, 6, 8, 10 and 12 kg ha^-1) for Cu and Zn respectively. A recommended N, P, and K at rates of 120, 60, 30 kg ha^-1, respectively, were also used as basal application. The status of available Cu and Zn by 0.1 HCl were found to be low in the soil. The application of Cu and Zn into the soils significantly (P<0.05) increased both maize DM and grain yields. Maximum grain yields and uptake in maize were established at 10 kg Cu ha^-1 and 8 kg Zn ha^-1, respectively. The estimated optimum rates for Cu and Zn under greenhouse environments were also established at 10 kg Cu ha^-1 and 8 kg Zn ha^-1, respectively. However, maize response curve showed that for optimum grain yield, concentration for Cu was determined to be 35.9 mg kg^-1, while for Zn it was 32.1 mg kg^-1. The current study showed that though the soils has a severe Cu and Zn deficiency, which could be due to their strong sorption capacity, and nutrients mining, due to intensive cropping, maize production can still be increased considerably in this soil and other similar soils in the same agroecological zone within a coastal plain sand derived soil by applying Cu and Zn at rates of 10 kg Cu ha^-1 and 8 kg Zn ha^-1, respectively.