Pearl millet/cowpea cropping system yields and soil nutrient levels

African Crop Science Journal, Vol. 4. No. 4, pp. 453-462, 1996 Pearl millet/cowpea cropping system yields and soil nutrient levels M. BAGAYOKO, S.C. MASON, S. TRAORE and K.M. ESKRIDGE *Corresponding Author Joint contribution of Institut d'Economie Rurale (IER), Barnako, Mali and Department of Agronomy, University of Nebraska, Lincoln, NE 68583-0915 U.S.A. Paper No. 11718 of the Journal Series of the Nebraska Agric. Res. Div. (Received 18 November 1996; accepted 13 December 1996) Code Number: CS96086 Sizes of Files: Text: 39.6K Graphics: No associated graphics files ABSTRACT Pearl millet [Penisetum glaucum (L.) R.Br.] and cowpea [Vigna unguiculata (L.) Walp] are important crops in traditional bush-fallow production systems in West Africa. Human population growth is forcing producers to consider alternative cropping systems and fertilizer application to meet food needs, by continuous, intercrop and rotational cropping systems on pearl millet and cowpea grain and stover yield, and maintaining soft nutrient levels. A long-term cropping system study with nitrogen applications of zero 20 and 40 kg ha^-1 was initiated at the Cinzana Research Station near Segou, Mali in 1990. The field had a leached tropical ferruginous (Ustalf) soil. Nitrogen fertilizer application increased pearl millet and stover yield linearly per year, but had no effect on cowpea. Rotation with cowpea increased pearl millet grain yield by 17 to 31% each year between 1991 and 1995, but had little effect on cowpea yield. Intercropping reduced yield of both crops every year, but the Land Equivalent Ration indicated a 14 % average increase in land use efficiency. After four years, soil of plots with the different cropping systems had similar levels of nutrients, except for phosphorous which was higher in continuous cowpea plots. Soil of plots with all cropping systems had lower level of pH, K, Ca, Mg and cation exchange capacity than fallow plots, indicating that all cropping systems were mining soil of nutrients. This research indicates that nitrogen fertilizer application up to 40 kg/ha and crop rotation with cowpea increase pearl millet grain and stover yield. Key Words: Crop rotation, grain and stover yield, intercropping, nitrogen RESUME Le mil [Penisetum glaucum (L.) R. Br.] et le niebe [Vigna unguculata (L.) Walp] sont des cultures importantes dans les systemes traditionnels en Afrique de l'Ouest. La croissance demographique pousse les Producteurs a considerer d'autres systemes alternatifs de culture et l'utilisation des engrais chimiques pour satisfaire les besoins alimentaires et maintenir le statut des elements nutritifs du sol. L'objectif de cette etude etait de determiner les effects des systemes de monoculture et de rotation sur la production de grains et de biomasse du mil et du niebe et le niveau des elements nutritifs du sol. Une etude du stem de culture de longue duree avec l'apport de zero, 20 et 40 kg/hectare a ete initiee a la Station de Recherche Agronomique de Cinzana non loin de Segou au Mali en 1990. La parcelle experimentale etait un sol du type "Sols ferrugimeux tropicaux lessives". L'application de l'engrai azote a augmente le rendement grain et de biomasse du mil de facon lineaire chaque annee, mais n'a eu aucun effet sur la production du niebe. L'association du niebe au mil a reduit le rendement des deux cultures chaque annee, mais le rapport de la surface equivalente a indique une augmentation moyenne de 14% de l'efficacite d'utilisation de la terre. Apres quatre annees de culture, les sols des parcelles portant les differents systemes de culture avaient des niveaux similaires d'elements nutritifs, a l'exception du phosphore qui etait plus eleve dans les parcelles de monoculture du niebe. Les sols des parcelles de tous les systemes de culture avaient des niveaux de pH, K, Ca, Mg et la capacite d'echange cationique plus bas que ceux de la jachere, indiquant ainsi que tous les systemes de culture etudies minaient les sol de ses elements nutritifs. Cette etude montre que l'appliation de l'azote a la dose de 40 kg/hectare et la rotation avec le niebe augmente le rendement grain et de bimasse du mil. Mots Cles: Rotation de la culture, rendement de grain, culture mixted, nitrogene Copyright 1996 African Crop Science Societ