Performances du maïs ("Zea mays") cultivé en couloirs de légumineuses arbustives à Yangambi (République démocratique du Congo)

Résumé

Experiments were carried out at Yangambi (Dem. Rep. Congo) from 1991 to 1993, within the framework of an interdisciplinary agroforestry research programme at the National Institute for Agronomic Study and Research of Congo, with the aim of investigating the impact of alley cropping with shrub legumes (Leucaena leucocephala, Tephrosia vogelli, Cassia spectabilis, Sesbania sesban) on the germination, flowering and yield of maize (cv Kasai 1) (figure 1). Alley cropping was found to have no effect on germination rate or flowering. During the third crop season, cropping with L. leucocephala and C. spectabilis gave higher maize yields in comparison to cropping with T. vogelli or S. sesban, or cropping in pure stands (tableau 2). Shifting cultivation is the main farming system in the Yangambi equatorial forest zone. This traditional system boosts soil productivity and provides stable rainfed crop production by tapping the regenerating potential of woody plants that colonize fallow fields during long periods between crop seasons [1]. In recent decades, this traditional system has no longer been applied because of the high population growth rate and increased land use. The shortened fallowing period has led to soil degradation and a decline in productivity. The alley cropping system enhances soil conservation and fertility, stabilizes farm production and food crop yields [2, 3]. In the present paper, we present results obtained during three maize crop seasons at Yangambi relative to inputs of legume shrub pruned branches.