Cocoa pod husk-derived organic soil amendments differentially affect soil fertility, nutrient leaching, and greenhouse gas emissions in cocoa soils

The depletion of soil nutrients and subsequent decline in yields on cocoa farms in west Africa is a major driver of shifting cultivation resulting in deforestation. In this paper, we show that compost and biochar, made from cocoa pod husks (a major farm waste but rich in nutrients such as P and K), could be used to improve soil nutrient availability in soils used for cocoa cultivation. Furthermore, we show that soil amendment with cocoa pod husks-derived biochar could be used to reduce nutrient leaching and as a strategy to reduce greenhouse gas emissions from cocoa soils receiving organic amendments. Overall, we show that composted and/or pyrolysed cocoa pod husks can be judiciously used to both maintain productivity on cocoa farms and increase the sustainability of cocoa production in west Africa.