Yield and quality evaluation of five tropical legumes in pure and mixed sward in the moist savanna of West Africa. (165)
Keywords:Dry-season, forage legumes, methane gas, mob-grazing
AbstractA study was conducted in Ogun state Southwest Nigeria, to identify legume species with resilience to intense defoliation through grazing, both in quality and quantity, in the moist savanna zone of West Africa. Five (5) forage legumes: Centrosema pascuorum Benth (Centro), Stylosanthes guianensis var. guianensis (Aubl.) Sw. var. guianensis (cook stylo), Stylosanthes hamata (L.) Taub. (verano stylo), Lablab purpureus cv. Highworth (L) Sweet (black seed lablab) and Lablab purpureus cv. Rongai (white seed lablab) were planted in 5 x 5 m pure plots and also in association with Panicum maximum (guinea grass) two (2) weeks after planting the grass. Legumes were drilled method at 10kg/ha for stylosanthes species and 13kg/ha for centrosema and 15kg/ha for both Lablab species. Legumes were evaluated through growth performance, disease incidence, drought tolerance and biomass dry-matter yield in 2011. During the dry season, mob-grazing using the Bunaji cattle was carried out on the entire plots in 2012 and biomass yield and forage quality of the regrowth was estimated. L. purpureus cv. Rongai was able to survive the dry season with about 40% staying green until early dry season. In mixture with Panicum, the CP contents of both S. hamata and L. purpureus cv. Rongai were significantly higher than the other legumes during the first year harvest. When the forage legumes were planted in mixed sward with Panicum in the first year, L. purpureus cv. Rongai gave the highest in vitro gas volume. Least volume of methane gas produced by both species of stylosanthes and L. purpureus cv. Rongai were similar in the first planting year. Its ability to stay green during the dry season and high regeneration potentials with higher CP contents after mob-grazing proved that L. purpureus cv. Rongai is suitable as a good livestock feed resource for the short dry season in the moist savanna of West Africa.