TY - JOUR

T1 - Selected shade tree species improved cocoa yields in low-input agroforestry systems in Ghana

AU - Asitoakor, Bismark Kwesi

AU - Vaast, Philippe

AU - Ræbild, Anders

AU - Ravn, Hans Peter

AU - Eziah, Vincent Yao

AU - Owusu, Kwadwo

AU - Mensah, Eric Opoku

AU - Asare, Richard

PY - 2022

Y1 - 2022

N2 - CONTEXT: Cocoa agroforestry systems differ in the diversity of shade tree species composition. Though cocoa benefits from shade, there is a lack of species-specific information on shade trees that enhance soil fertility and yield.OBJECTIVE: We examined how soil characteristics and cocoa yield were affected by eight commonly retained forest tree species, compared with unshaded control plots over a 3-year period.METHODS: Using 74 circular plots from 10 cocoa farms in the Western region of Ghana, we sampled soils from two random points within each plot. Soil nutrients at the beginning and end of the study were analyzed, and yield was expressed as number of harvested pods and dry weight of beans per hectare.RESULTS AND CONCLUSIONS: Levels of soil K and Ca were below recommended values. Although soil available phosphorus (P) was higher in control plots than under shade trees, yield around shade trees were higher than on unshaded plots. Cocoa yield differences between shade tree species and control plots were significant only in the major crop season, but not in the minor crop season. Cocoa yields under Cedrela odorata, Khaya ivorensis, Terminalia superba and Milicia excelsa were significantly higher than on control plots. Hence, the inclusion of specific shade tree species in cocoa agroforestry systems is important to maintain high yields in cocoa systems with low inputs.SIGNIFICANCE: To our knowledge, this study presents one of the first attempt to assess the impacts of specific shade tree species on soil characteristics and cocoa yield.

AB - CONTEXT: Cocoa agroforestry systems differ in the diversity of shade tree species composition. Though cocoa benefits from shade, there is a lack of species-specific information on shade trees that enhance soil fertility and yield.OBJECTIVE: We examined how soil characteristics and cocoa yield were affected by eight commonly retained forest tree species, compared with unshaded control plots over a 3-year period.METHODS: Using 74 circular plots from 10 cocoa farms in the Western region of Ghana, we sampled soils from two random points within each plot. Soil nutrients at the beginning and end of the study were analyzed, and yield was expressed as number of harvested pods and dry weight of beans per hectare.RESULTS AND CONCLUSIONS: Levels of soil K and Ca were below recommended values. Although soil available phosphorus (P) was higher in control plots than under shade trees, yield around shade trees were higher than on unshaded plots. Cocoa yield differences between shade tree species and control plots were significant only in the major crop season, but not in the minor crop season. Cocoa yields under Cedrela odorata, Khaya ivorensis, Terminalia superba and Milicia excelsa were significantly higher than on control plots. Hence, the inclusion of specific shade tree species in cocoa agroforestry systems is important to maintain high yields in cocoa systems with low inputs.SIGNIFICANCE: To our knowledge, this study presents one of the first attempt to assess the impacts of specific shade tree species on soil characteristics and cocoa yield.

KW - Theobroma cacao

KW - On-farm

KW - Soil fertility

KW - Available phosphorus

KW - Yield

KW - CACAO THEOBROMA-CACAO

KW - ECOSYSTEM SERVICES

KW - SOIL FERTILITY

KW - FOREST

KW - REQUIREMENTS

KW - DYNAMICS

KW - ECOLOGY

U2 - 10.1016/j.agsy.2022.103476

DO - 10.1016/j.agsy.2022.103476

M3 - Journal article

VL - 202

JO - Agricultural Systems

JF - Agricultural Systems

SN - 0308-521X

M1 - 103476

ER -