Pearl Millet Response to Microdose, Nitrogen and Phosphorus Application in West Africa.

 SEQ CHAPTER \h \r 1A five-year study to measure the response of pearl millet to application of microdose, nitrogen and phosphorus fertilizer was on research stations and farms in Burkina Faso, Mali and Niger. Analysis of variance indicated that grain and stover yields responses to fertilizer treatments varied by country and year. On average, microdose fertilizer application increased on-station pearl millet grain yield by 113% (225 to 479 kg ha^-1) in Niger, by 81% (351 to 637 kg ha^-1) in Burkina Faso, by 30% (764 to 1046 kg ha^-1) on sandy soil in Mali, and by 33% (1069 to 1417 kg ha^-1) on a heavy soil in Mali. On-farm pearl millet yield responses were similar, with grain yield increases of 76% (328 to 577 kg ha^-1) in Niger, by 180% (197 to 552 kg ha^-1) in Burkina Faso,  and 27% (1108 to 1448 kg ha^-1) in Mali. Stover yields increased 61% (1566 to 2626 kg ha^-1) in Niger, by 72% (929 to 1597 kg ha^-1) in Burkina Faso, and 66% (1545 to 2561 kg ha^-1) on a sandy soil in Mali, and by 50% (2500 to 3750 kg ha^-1) on a heavy soil in Mali. Additional N and P fertilizer further increased stover yield by 20 to 50%. Microdose application is a low cost investment that has a high probability to increase grain and stover yields across the West Africa pearl millet production area, but estimated N and P removals are negative and similar to zero fertilizer application and thus does not alleviate soil nutrient mining. Applications of microdose plus 30 kg N ha^{-1  and} 10 kg P ha^-1  are required to reverse soil mining in production systems with both grain and stover removed from the field.