The objective was to estimate the fixation of atmospheric nitrogen (Ndfa) by legume (Gliricidia sepium) trees for the benefit of cocoa (Theobroma cacao) trees in agroforestry systems.

Maize (Zea mays L.) is a major nitrogen consuming crop, as nitrogen is considered as an important determinant of its grain yield. Though inorganic fertilizer is widely recommended, the problem of high cost and inaccessibility limit its usage by resource poor farmers. Biochar application provides a new technology for both soil fertility and crop productivity improvement. With limited research on the suitability of biochar for soil improvement practices in Ghana, our objective was to determine the synergistic effect of biochar and inorganic fertilizer on the nitrogen uptake, nitrogen use efficiency, and yield of maize. Field experiment was conducted in Ghana, KNUST, in the major and minor raining seasons. Biochar was applied at 0, 5, 10, 15, and 20 t ha⁻¹ and fertilizer N applied at 0, 45, and 90 kg ha⁻¹. The results showed significantly (p < .05) higher N uptake, N use efficiency and yield of maize when biochar was applied with fertilizer N compared to both the control and sole N fertilizer plots. Biochar applied at 10 t ha⁻¹ supplemented with 45 kg N ha⁻¹ increased N uptake by 200%, and grain yield by 213% and 160% relative to the control in the minor and major rainy seasons, respectively. The greater yield of maize recorded on biochar-amended soils was attributed to the improved N uptake and nitrogen use efficiency. In conclusion, our finding suggests that the application of combined biochar and inorganic N fertilizer is not only ecologically prudent, but economically viable and a practicable alternative to current farmers’ practice of cultivating maize in Ghana.

Drought is the most critical abiotic threat to cocoa growth and productivity. The purpose of this review is to provide an overview of the recent research and developments which have contributed to the biostimulant properties of Arbuscular Mycorrhizal Fungi (AMF) and Potassium (K) fertilizer, and suggest the best research strategies for the application of these biostimulants to enhance cocoa growth and adaptation to drought conditions. We identified multiple services provided by AMF and K fertilizers: increase nutrients uptake, activating nitrate reductase, regulating photosynthesis and stomata conductance, improve water use efficiency, root growth etc. These multiple services could be efficiently exploited to enhance drought resilience and improve the survival rate of cocoa. Therefore, there is the need for further studies to assess the effectiveness in using either K or AMF or their combination in building the drought resilience of cocoa at the seedling phase; understand the rates of potassium fertilizers that will improve the physical (e.g. cell wall turgor, roots growth) and biochemical (e.g. Proline, polyamines, enzymatic) characteristics of cocoa seedlings to alleviate water stress. In addition, develop better K recommendations based on soil types, location specific and current cocoa varieties; understand the role of K and or AMF in enhancing drought resilience in cocoa under saline conditions and breeding cocoa genotypes with higher efficiency in K utilization and/or AMF colonization. Eventually, AMF and K can be developed as biostimulants as additional and complementary strategies to be used alongside others to improve cocoa drought resilience.

Environmental and climate change issues have exacerbated the existing gender inequalities in Ghana's cocoa sector. The current underrepresentation and unequal access to opportunities for women in climate action initiatives has negative implications for their livelihoods. This research focuses on how harvesting cocoa waste enabled the creation of a sustainable micro enterprise to encourage adoption of shaded cocoa production to generate biomass (waste) for organic compost production. The study followed a prescribed training programme for organic compost production and agribusiness management skills. The study employed the analysis of project notes and post-training community-visit observation records and interviews to assess the success of the training workshops and the overall project progress. Results from the analyses indicate that the knowledge and skills provided engendered motivation for a continuous and expanded adoption of climate-smart agri-innovation of shaded cocoa production. Further, the results show evidence of positive social, environmental, cultural, and economic impacts and favourable prospects of improved livelihoods for female cocoa farmers. These insights imply that SDG13, which calls for urgent climate action, can be integrated with SDG5, which places emphasis on gender equity, to improve the adoption of cocoa agroforestry and the livelihood of women in the cocoa sector of Ghana.