Integrated Management of Fertilizers, Weed and Rice Genotypes Can Improve Rice Productivity B.V. Bado, K. Traore, M.E. Devries, A. Sow, and S. Gaye Abstract The influence of weed control on fertilizer nitrogen use efficiencies (NUEs) by rice genotypes was studied in the Senegal River valley of West Africa with a field experiment during four rice growing seasons. It was hypothesized that integrated management of tech- nologies could improve rice productivity. The objec- tive was to develop integrated high-return technologies that improve irrigated rice-based systems productivity and profitability. Data indicated that rice grain yields were affected by N fertilizer, genotypes and plant den- sities. In good weed control conditions, optimum doses of recommended N fertilizer varied from 80 to 180 kg N ha –1 . Fertilizer N use efficiencies by genotypes were affected by weed control. Profitable management options of genotypes and N fertilizer recommendations have been identified. With a good control of weed, varieties and N fertilizer recommendations were sug- gested as integrated management options for farmers. But poor control of weed increased N lost, decreased grain yields and profitability. Two genotypes (WAS 55- B-B-2-1-2-5 and WAS 191-1-1-7 FKR) were found to be most competitive against weeds. However, no more than 60 kg N ha –1 should ever be recommended when weeds are poorly controlled. It was concluded that pro- ductivity and profitability of irrigated rice-based sys- tems could be improved with integrated management options of genotypes, fertilizers and weed. Keywords Fertilizer · Nitrogen · Weed · Varieties · Rice B.V. Bado () Sahel Regional Station, Africa Rice Centre (Africa Rice), BP 96, Saint-Louis, Senegal e-mail: V.Bado@cgiar.org Introduction Rice is a strategic crop in West Africa, an impor- tant source of food and farm income for most rural households in the region. In addition to its growing importance in rural diets, rice has rapidly become the major source of calories for most urban households in West Africa. While rice has proved to be a sustainable crop, preserving the natural resource base, West Africa currently only produces 40–60% of their total consum- mation in rice (Haefele et al., 2002). In 1995, Mali, Burkina Faso, Senegal and Gambia together imported 578,000 tonnes of milled rice, valued at US $154 million (WARDA, 2000). Enormous efforts and resources have been invested in the development of irrigation schemes to enhance irrigated rice production as a means of promoting food security and tackling rural poverty in the sub-region. With favourable climatic conditions, the potential for increasing irrigated rice productivity and output in the Sahel is indeed high (Dingkuhn and Sow, 1995). The adoption of structural adjustment and market liberal- ization policies, with support from the World Bank and IMF, has further enhanced this potential. These factors together offer an opportunity for increasing the com- petitiveness of the rice sector in West Africa (Kebbeh and Miezan, 2003). However, many factors limit farmer’s capacities to exploit potential production and market opportunity offered by rice. Rice yields are mainly limited by low inputs such as fertilizer, weed and pests and inadequate management of inputs, water and cropping systems. Although technologies have been developed to address some of these constraints, an important problem is that improved technologies generated to facilitate the productivity and profitability of irrigated rice systems 175 A. Bationo et al. (eds.), Innovations as Key to the Green Revolution in Africa, DOI 10.1007/978-90-481-2543-2_16, © Springer Science+Business Media B.V. 2011