ASSESSMENT OF COPPER LEVELS IN THE SOIL AND VEGETATION FOLLOWING REPEATED APPLICATION OF BOAREAUX MIXTURE TO A COCOA PLANTATION IN SOUTH EASTERN NIGERIA

Abstract

Copper concentration in an old cocoa plantation annually sprayed with bordeaux mixture to control a fungal disease was investigated. A nearby Gmelina plantation was used to obtain some background information. Samples of leaf, seed and bark of cocoa and Gmelina respectively as well as soil and some economic ground flora species from the two plantations were collected and analyzed for Cu and Fe. The concentration of Cu in the bark leaf, seed, ground flora and soil from Cocoa plantation were significantly higher by 95%, 87%, 72.2% and 53.6% respectively than those of Gmelina plantation. The highest concentration of Cu was in the cocoa bark (156.2mg kg-1). Cocoa seed contained 18.5mg kg-1 of Cu. Cocoa and Gmelina plantations had similar Fe concentrations only in their soil and ground flora samples. The leaf sample contained the highest concentration of Fe in both Cocoa and Gmelina plantations. The use of bordeaux mixture is gradually building up the Cu level in the Cocoa plantation, and urgent control need to be introduced on the use of the fungicide to reduce both the environmental degradation and the health risk posed to the local populace.



[Niger Agric. J. 34 (2003): 97-102]