Exploring maize-legume intercropping systems in Southwest Mexico

Maize yields in continuous maize production systems of smallholders in the Costa Chica, a region in Southwest Mexico, are low despite consistent inputs of fertilizers and herbicides. This study was aimed at investigating the prospects of intercropping maize (Zea mays L.) and maize-roselle (Hibiscus sabdariffa L.) mixtures with the legumes canavalia (Canavalia brasiliensis Mart. ex Benth) and mucuna (Mucuna pruriens var. utilis) for improving nutrient uptake and weed suppression. Farmer-managed experiments were established in two communities in the region during 2006 and 2007 using randomized split-plot designs. Maize monocrops and maize-roselle intercrops grown with different sources of nutrients were intercropped with both legume species, sown 4–6 weeks after maize. Neither the legumes decreased yields of maize nor roselle, whereas they caused a reduction of the weed biomass by 24–55%. Total aboveground biomass returned to the soil increased up to 36% and total N, P, and K uptake was increased on average by 52%, 24%, and 30%, respectively. Legumes acted not only as a N-fixing crop, but also as a “catch” crop, preventing N and K leaching. With its prostrate growth habit and adaptation to poor soil conditions, canavalia demonstrated agronomic advantages in comparison to mucuna