Vegetables are essential for food security and the quality of nutrition in Ghana. The government has a strong focus on the nutritional benefits of vegetables and the demand is substantial, which has made vegetable cultivation particularly attractive to the Ghanaian farmers. But vegetable cultivation is threatened by climate change. The fields provide too low yields, and farmers need more and more land to grow enough vegetables for a growing population. 

More heat, drought, and declining fertility in the soil

In Ghana, the annual mean temperature has risen by 1 degree over the past three decades. At the same time, the amount of rainfall has become more irregular, which means that the country has longer and longer drought periods interrupted by heavy rains. According to researchers from the Department of Agroecology at Aarhus University, the development seems to continue. The higher temperature gives a higher evaporation and at the same time the water from heavy rain often runs away from the fields on the surface. This results in a decrease in soil moisture and increased soil erosion. And this is bad news for farmers who want to grow vegetables and for consumers who want to buy them.

New project should help

The project, named “Building vegetable farmers resilience to climate change” is a collaboration between Aarhus University, DTU (Technical University of Denmark), University of Ghana, University of Cape Coast, Agropal West Africa and Fasterholt Maskinfabrik A/S.

"We want to explore whether a systematic approach can help ensure the production of high-quality vegetables year-round in Ghana, so that we can ensure farmers' livelihoods and at the same time ensure the nutritional needs of especially poor population groups," says professor Mathias Neumann Andersen from the Department of Agroecology.

The project focuses on two of the UN's global goals:

1. No Poverty - As farmers' conditions improve and they can grow more and better vegetables, they will also receive increased income and poverty will decrease in Ghana.
2. Zero Hunger - More high-quality vegetables all year round will ensure more stable prices and healthier food for everyone, so less hunger or malnutrition.

Objectives of the project

Overall, the researchers want to increase resilience to rising temperatures and more erratic rainfall patterns in small vegetable farming by using plant residues from the palm oil industry as fertilisers and to counter erosion and increase the amount of rain that infiltrates into the soil. They will identify more climate-resistant vegetable varieties, climate-smart irrigation systems, and opportunities to collect and store rainwater for irrigation.

More specifically, the project has the following objectives:

• Evaluate the effect of palm oil residues used raw, pyrolyzed (biochar) or composted on different types of soil and measure greenhouse gas emissions from it.
• Use field trials to determine the yield potential of climate-tolerant vegetable varieties with and without irrigation as well as manure production from palm oil residues.
• Evaluate new solar-powered irrigation systems in combination with rainwater collection as drought protection.
• Examine existing and new varieties of vegetables (e.g. okra and eggplant) for tolerance to high temperatures, drought, pests, and diseases.
• Analyse the socio-economic assumptions and effects of irrigation, use of palm oil residues and selected climate-stable vegetable varieties on farmers' income.
• Develop new sustainable business models so that farmers can invest in technology as well as improve and develop their skills so that they can more easily farm in the dry part of the year.

The project is an extension of the WEBSOC project, which has just been completed. Among other things, the WEBSOC project investigated what impact use of biochar could have on soil fertility. The results were very positive, but it was not possible to measure the long-term effects of biochar within the time period of the project. That opportunity comes with the ”Building vegetable farmers resilience to climate change” project, which will investigate the effects after 8 years.

Read more about the WEBSOC project here.

Behind the project