Moving methodologies to enhance agricultural productivity of rice-based lowland systems in sub-Saharan Africa

Abstract

The irrigated and rainfed lowland production systems in sub-Saharan Africa offer great potential to improve food security in the region. Rice yields in these systems are presently only at about 40 to 60% of the climate-determined yield potential across agro-ecological zones. To increase agricultural productivity a holistic approach to technology development is needed. This process is called integrated rice management (IRM), which is based on agro-ecological principles and on holistic thinking with wide ranges of technological options that encompass the entire rice cropping cycle. In both irrigated and rainfed lowland systems key factors for raising productivity are soil fertility and weed management. Improved soil fertility and weed management in irrigated systems in Senegal are highly profitable; yields can be raised by 2 t ha^{- 1}, closing the yield gap between actual and potential yield by 30%. In inland valley lowlands improving soil fertility and weed management also results in substantial yield increases, depending on water control. We compare approaches used to technology development in Sahelian irrigated systems and in inland valley systems in Côte d’Ivoire. We illustrate that the need for early farmer participation in technology development increases when moving from the relatively uniform high-precision Sahelian irrigated farming systems to the more diverse, low-precision inland valley lowland systems further south. Technologies need to be more flexible and less fine-tuned in the inland valley systems as compared to the Sahelian irrigated systems. More emphasis also needs to be placed on farmer innovations and adaptation according to the prevailing agro-ecological and socio-economic conditions rather than on technology prescriptions, and on farmer-experimentation. Scaling-out of results in the Sahelian irrigated systems was done through change agents of NGOs and national extension authorities and publicity campaigns. Scaling-out of results in the inland valleys relied on the establishment of rural knowledge centers and farmer-to-farmer training. R&D institutions have a much more facilitating role rather than a directing role, when comparing the irrigated Sahelian systems with the inland valley lowlands. In both systems, simple decision support tools, such as a cropping calendar can be extremely valuable to farmers. WARDA and IFDC have developed a participatory learning and action research (PLAR) curriculum for IRM in rice-based inland valley systems. Ultimately IRM needs to move to other aspects of integrated natural resources management (INRM) within a watershed or water basin that are relevant to stakeholders. However, the peoples-orientation, typical for PLAR, will be the leading principle, be it IRM or INRM.