Screening of indigenous forage legumes as potential fodder crops and protein source for livestock in central Namibia

The objective of the study was to screen indigenous forage legumes found in central Namibia and evaluate their potential as fodder and protein source for livestock. The growth rate, biomass yield and nutritional value of four indigenous legumes (Otoptera burchellii, Vigna lobatifolia, Crotalaria argyraea and Cullen tomentosum) and four improved legumes (Lablab purpureus, Medicago sativa, Canavalia ensiformis and Vigna unguiculata) were evaluated in a split-plot design with Single superphosphate at varying levels (0, 60, 80 and 100 kg P/ha). Fertilizer application up to 80 kg P/ha increased biomass and 100-seed weight; responses for O. burchellii were however inconsistent. The legumes differed (P < 0.05) in biomass yield; least square means (tons/ha) were: L. purpureus (8.9  0.3), V. lobatifolia (1.5  0.4), O. burchellii (2.5  0.3), V. unguiculata (4.4  0.3), C. tomentosum (5.1  0.4), C. ensiformis (4.0  0.3) and M. sativa (4.7  0.3). The 100-seed weight increased as P fertilizer level increased. The CP, ADF, NDF, ash and calcium differed (P < 0.05). The least square means for CP (% DM) at bloom stage were: L. purpureus (21.9 0.3), V. lobatifolia (18.9 0.4), O. burchellii (21.3 0.3), V. unguiculata (18.90.3), C. tomentosum (20.90.3), C. ensiformis (20.40.3) and M. sativa (26.90.3). NDF ranged from 30.5 ± 1.6 to 42.4 ± 1.8 % DM. Phosphorus content was similar (P ˃ 0.05) among legumes. L. Purpureus and the indigenous legumes O. burchellii and V. lobatifolia have potential as fodder and protein source ipso facto could contribute substantially to improving nutrition of ruminants in central Namibia.