Utilization of Azolla in rice production in West Africa: potentials and constraints

Abstract

Efforts to develop Azolla utilization in rice production in West Africa were sporadic until 1980. Azolla species, A. caroliniana, A. microphylla and A. pinnata var. imbricata, adapted well in the semi-arid climatic zones while A. pinnata var pinnata performed better in humid climatic zones of the region. The productivity of adapted Azolla strains in the region is as good as, or better than, that found in Asia. A zolla productivity in semi-arid climatic zones reached, on the average, about 200 g fresh weight (FW) m−2 day−1, which is higher than that in humid tropic climatic zones. The yield responses of rice to the incorporation of a monocrop of Azolla (20 t FW/ha) before rice transplanting is equivalent to the response of rice to the application of 30–40 kg N/ha. Efforts devoted to the development of methods for on-farm Azolla production and the integrated use of Azolla in rice-based farming systems in the region, however, are still very limited.