Shade Trees in Cocoa Agroforestry Systems in Ghana: Influence on Water and Light Availability in Dry Seasons

The objective of this paper was to assess the influence of single standing shade trees in cocoa agroforestry systems on soil moisture and light availability for cocoa in the dry seasons and how these environmental factors affect potential pod yields of cocoa. The research was conducted in a moist semi-deciduous forest zone of Ghana. Seven different shade trees that were commonly found in cocoa systems were selected. An effect ratio was used to compare tree sub-canopy effects to the open area effects. Morinda lucida (0.19), Spathodea campanulata (0.16) and Ficus capensis (0.13) showed favourable soil moisture conditions, however Citrus sinensis (-0.26) revealed a lower soil moisture content in the sub-canopy. Entandrophragma angolense and Terminalia superba had the highest transmitted percentage light of 69.2% and 67.1% respectively and the lowest being Mangifera indica (3%). The potential pod yields of cocoa were higher under Morinda lucida (0.40), Terminalia superba (0.40) and Entandrophragma angolense (0.35) but lowest under Mangifera indica (-0.55). Morinda lucida, Spathodea campanulata, Entandrophragma angolense and Terminalia superba in cocoa agroforestry systems potentially ensure higher soil moisture content and light availability in the sub-canopy, especially during the dry seasons, which could translate into higher cocoa pod yields.