Nutrient and Structural Carbohydrate Partitioning in Pearl Millet

Abstract Cereal stovers and other crop residues are vital feeds for ruminants during the 6‐ to 8‐mo dry season in mixed farming systems of semiarid West Africa. Reducing the competition between livestock and soil fertility is crucial to the sustained productivity of these farming systems. A 2‐yr field study was conducted in Niger on a sandy siliceous isohyperthermic Psammentic Paleustalf to determine the effects of fertilizer N (15 and 45 kg ha −1 ) and P (4.4 and 17.4 kg ha −1 ) on dry matter (DM), N, P, and structural carbohydrate distribution in plant parts of pearl millet [ Pennisetum glaucum (L.) R. Br.]. Fertilizer N increased total millet DM by 13%, N uptake by 63%, and P uptake by 29%. Fertilizer P increased total millet DM by 100%, N uptake by 80%, and P uptake by 140%. Fertilizer N increased millet grain yield only during the year of adequate rainfall, whereas fertilizer P increased yields during both years. Fertilizer N increased and fertilizer P decreased the N concentrations in millet stover. Fertilizer P increased the P concentrations in all upper plant parts. The average total millet DM of 2.75 Mg ha −1 was partitioned into grain (18%); animal feed consisting of chaff, immature panicles, upper stover and tillers (41%); and middle and lower stover components for soil conservation (41%). Partitioning was not affected by fertilizer addition. Of the total N (33.4 kg ha −1 ) and P (5.2 kg ha −1 ) uptake, 32 and 40% were contained in grain, 41 and 40% in animal feed, and 27 and 20% in components for soil conservation. Results of our study show the importance of N and especially P in increasing grain and forage yield and quality, and that stover can be managed more effectively to raise both crops and livestock in a more sustainable manner.