Maize-bean intercrop weed suppression and profitability in Southern Ethiopia

Cereal-legume intercropping oft en results in increased productivity, weed suppression, and N supply. The agronomic and economic benefits of maize-bean (Zea mays L.-Phaseolus vulgaris L.) intercropping were studied for 5 yr in a complete factorial with: 0, 1, and 2 weedings (W0, W1, W2); and single (MB) and double (MBB) rows of bean alternated with one row of maize. Sole crop maize and bean were included. Weed infestation in intercrop was 30% less compared with sole crop bean but with inconsistent differences across years. Weed biomass was 13% less with MBB compared with sole-cropped maize. Ears m -2 were 55% more in seasons with better rainfall compared with 1999 and 16% more with W1 or W2 compared W0. Mean maize grain yield was 3.74 Mg ha -1. Weeding frequency (WF) effect on maize grain yield was inconsistent across years but yield was 75% more with W2 compared with W0. Overall, maize grain yield was 19% more with MB compared with MBB but the effect was significant in 1997 only. Mean bean yield was 1.07 Mg ha -1 and was inconsistently affected by treatments across years. Bean yield was on average 52 and 67% more with W1 and W2, respectively, compared with W0, and 35% more with MB compared with MBB. Intercropping resulted in land equivalent ratios (LER) of 1.0 to 2.4 with a WF effect. Mean net income (NI) was greatest with MB and W1. Overall, intercropping suppressed weeds and was more productive and economical than sole crop production. © 2011 by the American Society of Agronomy. All rights reserved.