Forage yield and quality of intercropped corn and soybean in narrow strips

Maize-soybean intercropping can increase forage quality with no detrimental effect on dry matter (DM) yield. The objective of this study was to compare corn-soybean intercrop in narrow strips with corn as monocrop in terms of DM yield and forage quality. This study was conducted in Matamoros, Coahuila (Mexico) in 2006 and 2007. Intercrops were established in rows spaced 0.50 m apart, evaluating alternate corn-soybean strips with one, two, three, and four rows per crop, and a treatment using an alternate twin-row planting pattern per crop, with a 1.0-m row-spacing. As control treatments, monocrops of corn in rows 0.76 m apart and soybean in rows 0.50 m apart were evaluated. A randomized complete block design with four replications was employed. Corn-soybean intercrop produced DM yields similar to those of monocropped corn due to higher corn yields in border rows adjacent to soybean. Crude protein (CP) yields per hectare in intercrop treatments were higher (27.5 to 42.8%) than those of monocropped corn, due to greater CP concentrations in intercrops (16 to 21 g kg(-1)). When soybean was harvested at the beginning maturity stage (R7), neutral detergent fiber concentration was reduced by 60 to 63 g kg(-1) in corn-soybean intercropping compared to corn monocrop. Acid detergent fiber was not altered by intercropping. Results indicate that maize-soybean intercrop in narrow strips can provide forage quality advantages without affecting yield.