Response of improved robusta coffee to location and management practices in Ghana

Studies were carried out at three locations in Ghana to investigate the effects of Glyricidia maculata shade intensity and of the spacing of coffee on the growth and yield of improved robusta coffee. The three locations selected fall within ecological zones which could be described as suitable, moderately and marginally suitable in terms of rainfall availability and soil conditions. The experimental design was a split plot with shade as the main plot and coffee spacing as the sub-plot. The four levels of shade were: no shade, and Glyricidia maculata at densities of 70, 90 and 185 per ha corresponding to sparse, moderate and heavy shade conditions. The coffee spacings were 3 m x 2 m, 3 m x 2.2 m, 3.5 m x 2 m and 3.5 m x 2.5 m giving plant populations of 1670, 1520, 1430 and 1140 per hectare, respectively. There were no effects of shade or spacing on coffee seedling growth at all locations during establishment. Sparse shade gave higher yields in the suitable areas. Moderate shade was required for the moderately and marginally suitable areas. In general, closely spaced coffee gave higher yields than the widely spaced coffee at the suitable and moderately suitable areas whilst there was virtually no response to coffee spacing in the marginally suitable area. There were no interaction effects of shade and spacing on coffee growth or yield. Biennial alternation of coffee-bearing associated with seedling materials was observed in this study.