Tropical Grasslands (2006) Volume 40, 111118
Effect of Lablab purpureus and Vicia atropurpuria as an intercrop, or in a crop rotation, on grain and forage yields of maize in Ethiopia
ABUBEKER HASSEN1, LEMMA GIZACHEW2 AND N.F.G. RETHMAN3
1Oromiya Agricultural Research Institute, Adami
Tulu Research Center, Zeway, Ethiopia
The study investigated the effects of maize-annual forage legume associations on maize and fodder production for 4 years in the subhumid zone of western Ethiopia. Lablab purpureus (lablab) and Vicia atropurpuria (vicia) were grown as pure crops or as intercrops in maize at 2 planting dates (simultaneous vs delayed 6 weeks) for 3 consecutive years (1994–1996) and pure maize was planted in all plots in the fourth year (1997). Intercropping significantly (P < 0.05) reduced grain yield in the 3rd year, but its effect on stover yield was not significant (P > 0.05). Among the intercrops, simultaneous planting of lablab significantly (P < 0.05) reduced grain and stover yield but increased forage dry matter (DM) yield. Lablab resulted in lower (P < 0.05) grain yield and higher total fodder (maize stover + forage DM) yield than vicia intercropped simultaneously with maize. Delayed planting, however, did not affect (P > 0.05) grain, stover, forage DM or total fodder yields. Forage yield of lablab was significantly (P < 0.05) higher than that of vicia, as both a monoculture and an intercrop planted simultaneously with maize. Plots under lablab and vicia monocultures for the previous 3 years produced maize yields comparable with those on fertilised plots. Among intercrops, the residual effects of simultaneously planted lablab were (P < 0.05) greater than for delayed planting. Grain yields following lablab were greater (P < 0.05) than following vicia both as a monoculture and as a simultaneously planted intercrop. When planted as a monoculture or simultaneously planted intercrop with maize, lablab appeared superior to vicia in terms of its ability to improve both feed supply and soil fertility.