Effects of copper-based fungicide application on cocoa growing soils and plants in Fenaso of the Amansie Central District, Ashanti Region,Ghana
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Date
2014-11-20
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Abstract
Copper based fungicide remains the most effective way to control the canker that reduces
the higher yield of the brown gold, cocoa for the people of Fenaso and the country at
large. However excessive application of the fungicide leaves a higher percentage of
residual copper in the soil and plants which affects the quality of cocoa produced in the
area. 30 selected cocoa farms from Fenaso, in the Amansie Central District of Ashanti
Region which had experienced repeated application of copper-based fungicide were
sampled to study the total copper in two soil depth of three of spraying age categories
together with cocoa parts, namely seeds, leaves and bark. The relationship between
copper concentrations and the soil pH and organic matter in the soils were also studied.
An unsprayed farm land at the same area was sampled for control. Mean total copper
concentration for three spraying age categories-below 10 years, 10-30 years, and above
30 years of the top soil were 22.37 mg/kg, 22.46 mg/kg and 23.97 mg/kg respectively
with corresponding mean of sub-soil as 18.08 mg/kg, 17.34 mg/kg and 17.91 mg/kg.
Analysis of results indicated that copper concentrations of the soil samples from sprayed
cocoa farms at both depths were significantly different from the corresponding copper
concentrations from unsprayed farm land (p < 0.05). The analysis also showed a
significant difference between top soil and sub soil which indicated that the mean copper
concentration of top soil was always greater than corresponding sub soil. No significant
difference was obtained in the three spraying age categories on total copper concentration
pH values and organic matter content of soil the samples (p > 0.05). The regression
analysis of the results indicated positive relationship between total copper concentration
and soil pH as well as organic matter. Copper concentration of cocoa beans differed
significantly from leaves and bark (p < 0.05). The mean copper concentration of the
seeds, leaves and bark were 37.3 mg/kg, 16.10 mg/kg and 16.5 mg/kg respectively. Even
though the cocoa growing soil of Fenaso is contaminated with copper based fungicide, the
cocoa beans from the area are far below the health risk of consumption. In future, more
research should be conducted on different cocoa farms nationwide to complement with
the conclusions made in this study.
Description
A thesis submitted to the Department of Theoretical and
Applied Biology,
Kwame Nkrumah University of Science and Technology
in partial fulfillment of the requirements for the degree of
Master of Science in Environmental Science,