Exploring maize-legume intercropping systems in Southwest Mexico.

摘要

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.