Is conventional small-scale cotton-based agriculture sustainable in West and Central Africa?

The sustainability of agricultural practices seems to be a suitable concept for evaluating both the agronomic and economic performance of conventional and conservation agriculture. In this study, the concept of sustainability was analysed through its main three components: economic sustainability, also called economic efficiency, dealing with the ability of the farming system to ensure sufficient and competitive production to fulfil market and population needs; social sustainability, or social equity, dealing with agricultural ability to ensure equitable revenues or returns for different stakeholders in the agricultural production chain; ecological sustainability, dealing with intergenerational preservation of the environment, referring here to the sum of natural resources used to ensure agricultural production, such as soil fertility. Ecological sustainability is commonly the only aspect of sustainability taken into account by agronomists. The sustainability of conventional agriculture was addressed in this study in small-scale cotton-based agriculture surveys in northern Cameroon. The economic efficiency of cotton in conventional agriculture was analysed through a database covering several years of an ongoing agricultural survey by Sodecoton (Cotton Development Company), while social equity was addressed based on the distribution of different production costs among cotton production stakeholders. Ecological sustainability was analysed through agronomic variables, such as yield variation over time, and mainly soil fertility trends. The results of the study revealed that the economic efficiency of cotton cultivation in conventional agriculture, after reaching acceptable levels since 2000, mainly due to high yields and prices and low input costs, is now declining. For example, fertiliser prices varied from 500 USD per ton in 2005 to more than 1,000 USD per ton at the turn of 2008. Social equity, even though strongly reinforced by an equalizing price and input costs determination system, is limited with substantial ecological differentiation between ecological areas, varying from 600 mm of rainfall in the far North to 1,200 mm of rainfall -20 in the South of the cotton belt, hence affecting different respective yields. A consideration of soil fertility, decreasing yields and increasing expenditure for fertilisers and other water-harvesting and soil conservation technologies, revealed a progressive weak response of soil resources to cropping system management. Conservation agriculture appears to be a more suitable alternative for small-scale cotton-based agriculture to attain the main three objectives of sustainable agriculture, since it can ensure the economic efficiency of the farming system, better social equity and better soil resource management. (Résumé d'auteur