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Effect of Shade Trees in Cocoa Agroforestry Systems on Water and Light Availability in Dry Seasons

Czech University of Life Sciences Prague, Department of Crop Sciences and Agroforestry, Czech Republic

Abstract

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.The averages of the individual tree sub-canopy and open area readings were calculated to represent their respective replicate values.Data were analysed as one-way analysis of variance (ANOVA) using the R Statistical Package. For each variable, normal distribution was tested using the Shapiro-Wilk normality test for homogeneity of variances. Significant ANOVAs were subsequently assessed using Tukey’s Honestly Significant Difference (HSD) test and probability was set at 0.05 for the statistical tests. Morinda lucida (0.19), Spathodea campanulata (0.16) and Ficus capensis (0.13) showed favourable soil moisture conditions, however Citrus sinensis (-0.28) 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 (0.34) 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.

Keywords: Cocoa agroforestry, cocoa yields, dry seasons, light, shade trees, soil moisture

Contact Address: Dennis Kyereh, Czech University of Life Sciences Prague, Department of Crop Sciences and Agroforestry, Kamycka 129, 165 21 Prague, Czech Republic, e-mail: kyerehftz.czu.cz