Award details

Remediation of Cocoa Soils in Ghana as a Route to more Sustainable Cocoa Production

Reference	BB/S014454/1
Principal Investigator / Supervisor	Professor Paul Hadley
Co-Investigators / Co-Supervisors	Dr Laura Atuah, Dr Godfred Kweku Awudzi, Dr Dadson Awunyo-Vitor, Dr Andrew Daymond, Dr Owusu Domfeh, Professor John Hammond, Dr Amos Quaye, Dr James Robinson, Dr Tom Sizmur
Institution	University of Reading
Department	Sch of Agriculture Policy and Dev
Funding type	Research
Value (£)	516,169
Status	Completed
Type	Research Grant
Start date	01/04/2019
End date	31/03/2022
Duration	36 months

Abstract

Degradation of soils on cocoa farms is a major factor facing the cocoa sector in West Africa. The project will consider how farm wastes (pod husks and prunings from cocoa and shade trees) can be utilised as soil amendments through composting and pyrolysis. Whilst studies have been conducted on ashed cocoa pods, there are knowledge gaps in terms of the efficacy of co-composted pod husks and pyrolyzed pod husks/ prunings as soil amendments. To address these issues, we will: i. examine the chemical and physical of co-composted and pyrolyzed pod husks/ pruning compared with raw materials with particular attention to the chemical form of P in wastes, composts and biochars and to changes in the C:N ratio. ii. examine whether Phytophthora spores (causing Blackpod disease) are eliminated through the composting process. iii. utilise the composted and pyrolyzed materials in on farm trials. The impact of these soil amendments on the performance of cocoa trees will be evaluated in terms of growth and yields as well as on the presence of pests and diseases in the field. iv. compliment field trials with detailed pots trials which will examine the performance of seedlings grown with different composts and subjected to abiotic (water deficit and high temperature) and biotic stresses (presence and absence of pests and diseases). v. assess changes in nutrient availability in the amended soils from the field and pot trials through examination of both the physio-chemical and biological properties of the soils. vi. explore changes in soil microbiology and macro-fauna in the amended soils and also within shaded versus non-shaded cocoa. In addition to these experimental approaches, a cost: benefit analysis will be conducted on the use of composted and pyrolyzed materials on cocoa farms. Farmers will be engaged in the project through on-farm trials and the results disseminated through farmer field schools, a manual and video and an end of project workshop.

Summary

Summary Cocoa is grown extensively in West Africa, producing 75% of world production. Ghana is the second most important cocoa producing country, where cocoa production provides a livelihood for an estimated 800,000 smallholder farmers. One of the main challenges facing the cocoa sector in West Africa is long-term soil deterioration on cocoa farms because of the depletion of soil nutrients caused by poor farming practices. This has resulted in a shifting cultivation pattern, and migration of cocoa farmers into virgin forest areas which is clearly unsustainable. Measures to improve soil health would improve both on-farm yields and thus the livelihoods of smallholder cocoa farmers. Previous collaborative research between the University of Reading and the Cocoa Research Institute of Ghana (CRIG) has demonstrated that many cocoa farms are deficient in key soil nutrients but also that inorganic fertilisers are unaffordable for many farmers. Against this background, this project seeks to explore routes for soil improvement on cocoa farms through utilisation of on-farm waste products, thereby contributing to more sustainable crop production and thus maintenance of livelihoods of smallholder cocoa farmers. The project will explore the use of composted and pyrolysed (burning organic materials in the absence of oxygen to produce "biochar") farm waste as soil amendments to improve soil fertility and health on cocoa smallholdings. Experiments will be conducted on a network of cocoa farms, established in a previous project, to ascertain the impact of composted farm waste and biochar on the performance of established cocoa trees. This will be evaluated through changes in yield and assessments of plant health by measuring the presence of pests and diseases. Shade trials at CRIG will also be utilised to ascertain the impact of maintained overhead shade trees on soil micro and macro fauna. Complementary experiments will also be conducted in the greenhouses of CRIG on seedlings inpots to ascertain the impacts of different soil amendments on the performance of juvenile cocoa. These experiments will also assess whether the performance of plants subjected to drought is improved by cultivation on soils ameliorated with different composts. Furthermore, the greenhouse experiments will consider whether plants grown in soils ameliorated with different composts are less susceptible to attack by insect pests and by diseases. Additional pot experiments will be conducted at the University of Reading in which cocoa seedlings grown in different soil amendments will be subjected to different temperature regimes within growth cabinets. Analyses will be conducted on the properties of soils amended with composts. These will assess the extent to which cation exchange capacity and availability of nutrients are improved through composting and biochar production. The microbiology and macrofauna of compost amended soils will be compared with controls as a critical factor that impacts on nutrient availability to the crop. The cost: benefit ratio of using composts and biochar will be explored and communicated to farmers through farmer field schools in the latter stages of the project. These events will be conducted on farms on which the trials were conducted and composting methods/ pyrolysis methods will be demonstrated to farmers. A summary of our findings will be presented at an end of project workshop which will be held in Ghana and attended by key stakeholders in the cocoa production chain. Furthermore, we will produce a manual and video that will be used as tools by extension agents to take the technologies developed out to larger numbers of farmers

Impact Summary

Impact Statement Ghana is the world's second largest producer of cocoa and around 800,000 smallholder farmers are engaged in cocoa farming at a subsistence level. At a national level, cocoa exports account for a considerable proportion of Ghana's GDP (estimate for 2004 to 2008 is 39% of GDP)[1] and cocoa is the third biggest export commodity and foreign exchange earner[2]. However, the sustainability of cocoa production is a major concern. Cocoa farms typically have a productive life span of between 20 and 30 years, during which the soils become depleted of key nutrients and yields fall. As a consequence, farmers will often move to new land, much of which has, to date, been virgin forest. This practice is set to become prohibited with the Ghanaian government, together with leading chocolate and cocoa companies, agreeing a framework to end deforestation associated with cocoa production as part of the 2017 UN Climate Change Conference (COP23)[3]. At the same time, the Ghanaian Government, and the cocoa sector more widely, have made clear in the framework their commitment to growing more cocoa on less land. The methods developed to improve soil health in this proposal will be expected to increase yields and maintain more sustainable productivity on smallholdings. This, in turn, will have an impact on the livelihoods of cocoa farmers and on the national economy. The primary beneficiaries of this research will be cocoa farmers who are predominantly smallholders and depend on cash from the sale of cocoa to support their livelihoods and education of their children. The application of low cost, organic soil amendments will be expected to improve and maintain crop yields from existing lands with a concurrent benefit to farmer livelihoods. The transfer of technologies that enable farmers to produce compost and biochar from farm wastes will enable farmers to become less dependent on fertilisers that may vary in price according to levels of subsidy at any particular time. Secondary beneficiaries of the research will be local entrepreneurs who may adopt the composting and pyrolysing techniques identified in the project to produce soil amendments to sell commercially. Furthermore, there is the potential opportunity for farmers to diversify their incomes through the production of soils amendments. Providing farmers with technologies to maintain soil health will enable sustainable cocoa production, maintaining the long-term viability of cocoa farms and thus removing the driver for shifting cultivation. This will help the Government and cocoa sector to meet their commitment to grow more cocoa on less land, and not at the expense of tropical forests that represents major stocks of carbon. References [1] Ofori-Bah et al. Ecological economics 70, 1508-1518 (2011) [2] http://www.worldstopexports.com/ghanas-top-10-exports/ [3] http://www.worldcocoafoundation.org/cocoa-forests-initiative/

Committee	Not funded via Committee
Research Topics	Crop Science, Plant Science, Soil Science
Research Priority	X – Research Priority information not available
Research Initiative	GCRF Sustainably Enhancing Agricultural Production [2018]
Funding Scheme	X – not Funded via a specific Funding Scheme

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