PRIORITY SETTING IN RESEARCH FOR SUSTAINABLE LAND-USE - THE CASE OF THE ADJA PLATEAU, BENIN

The Projet Recherche Appliquee en Milieu Reel is situated on the Adja Plateau, Southwest Benin. The project is responsible for a FSR&D programme that aims at sustainable use of the so-called Terres de barre. Technologies tested in this context include seasonal fallowing, using Mucuna pruriens cv. group Utilis (weed control, green manure), planted fallows using fast-growing species such as Acacia auriculiformis and hedgerow intercropping systems (various woody auxiliary species). In this paper the local farming system is analyzed to identify key parameters that determine the possibilities for technology adoption. Parameters include: function and history of fields; tenureship; the field's position with regard to fertility flows in the farming system. The paper also aims at understanding the reasons behind low crop yields, in this case maize. An analysis of the soil's chemical fertility, using a computer-based fertility assessment model and data from literature, shows some anomalies with respect to the availability of nutrients from organic matter. Data presented on the use of green manures and oil palm fallow compared to cultivated fields make it likely that organic matter management is a crucial factor. in sustainable use of these soils (maintenance of soil structure and soil life). Given key parameters, a matrix is used to determine potential niches in the farming system for the various biomass production technologies mentioned previously, including the locally developed planted fallow based on oil palm.