Abstract
Under-canopy sprinkler irrigation, aimed at maintaining the soil near field capacity was superimposed on an existing shade and fertilizer trial for mature Amelonado cocoa over three consecutive years. The overall responses during two years when the rainfall was about average were 12 and 17 per cent. In a year with a very severe dry season, irrigation increased yield by over 40 per cent to the level obtained in years with favourable rainfall. Irrigation suppressed flushing but stimulated flowering and setting; cherelle wilt was reduced by irrigation, particularly at the end of the dry season. Irrigation had very little effect on the phenology and cropping pattern. Recent studies with the pressure chamber suggest that soil irrigation provides only a small degree of control of internal moisture status in mature trees during an average dry season in Ghana and that stress develops under conditions of high evaporation regardless of soil moisture status.
