Several small farmers in the south of Côte d’Ivoire have developed their own way of ‘hors sol’. 90% of these very small farms grow tomatoes for the Abidjan market. This system is based on used fertilizer bags and other woven plastic bags filled with a mixture of soil, organic matter and fertilizer. This mixture has been wetted and heated for approximately half an hour on a hot, iron plate. Under this plate a wood fire is maintained. When cooled down the bags are filled and put on a black plastic sheet that covers the soil.
This practice is covered in the report Horticulture in Côte d’Ivoire, written by Jan Arie Nugteren with the Dutch organisation RVO. In this report you can read a detailed description about the vegetables, fruit and ornamental plants sector in Ivory Coast and about the opportunities for horticulture companies.
Ivory Coast’s climate is favorable for the cultivation of flowers, vegetables and fruit. But the quality of the products is often insufficient for export. There is a lot of work to do for Dutch experts in the entire chain, from seed breeding, soil analysis and fertilization to management, logistics and refrigeration technology.
Hors Sol
The report explains how it is not very clear at what temperatures and for how long the heating of the bags is done. Often the farmers do not use a thermometer during the process. Sterilisation at 120 ⁰ C is not to be expected without pressurized vessels so in reality there will be a sort of ‘pasteurisation’ taking place, which is not bad as the beneficial microorganisms can escape extinction. Often these farms are also covered with transparent plastic sheets to prevent the heavy rainfalls from washing out the nutrients and giving way to fungal and bacterial attacks.
However, Bacterial Speck (Pseudomonas spp.) is still observed a lot, even when plastic covers protect against rain. This is probably due to lack of air circulation causing a high relative humidity and high temperatures in the ‘greenhouse’.