Impact of fertiliser application on cocoa yields in Ghana: An analysis of cocoa bean yields in farmers’ plantations

Abstract

Nutrient mining from cocoa plantations in Ghana occurs continuously as pods and beans are taken from cocoa farms. The effects of fertiliser application on yield of cocoa was investigated over a ten-year period by monitoring yields in the farms of 256 farmers in the Ashanti, Brong Ahafo, Central, Eastern and Western Regions of Ghana. Selection of farms was limited to farmers that planted recommended mixed-hybrid variety, and within the age class of 10 to 15 years. Data were taken from two separate field monitoring. In the first group of farms monitored over a ten-year period (2009/10 to 2018/19), only granular type of fertilisers was applied on the farms of 99 farmers. In the second set of data taken over a six-year period (2013/14 to 2018/19), 157 farmers who applied both granular and foliar type of fertilisers were monitored. At each farm, a 0.2 ha plot was demarcated for each fertiliser type. A plot receiving no fertiliser application was included as a control for comparison. The experimental design was a randomised complete block with the locations (Farmers’ plantations) in each region serving as blocks. That is, at each location, a Farmer’s plantation is divided into the various treatments applied. Data on total number of pods was taken on each farmer’s plantation for two or three years after fertiliser application. Data collected were subjected to Analysis of variance. The results showed significant impact of fertiliser application on cocoa production in Ghana. In the farms that received only granular type of fertilisers, the average yield increases across the five regions was 73%, whereas in the second that had both granular and foliar types, the yield increase was 98%. There was no interaction between fertiliser type and Region for bean yields, except when the data on fertilised plots were disaggregated into foliar-applied and granular-applied farms. The result implies that both granular and foliar type of fertilisers recommended by Ghana cocoa board will provide similar levels of yield increment in the majority of cocoa producing Regions in Ghana