Productive and Economic Analysis of Corn and Alfalfa Intercropping.

Intercropping of corn and alfalfa is not a common practice because alfalfa generally reduces corn yield.  With the availability of glyphosate-resistant corn and alfalfa, and the use of growth regulators, corn-alfalfa intercropping has interesting potential. The objective of this research was to evaluate the productivity and profitability of corn-alfalfa intercropping system, with the aim to increase alfalfa productivity in the first year of production. The experiment was conducted in Fargo and Prosper, ND.  The design was a RCBD with four replicates and a split-plot arrangement, the main plot had two-row spacing (RS), 61 and 76 cm, respectively, Treatments in the subplot were: 1) Corn alone (check), 2) Corn intercropped with alfalfa, 3) Corn intercropped with alfalfa + prohexadione (PHX). Both alfalfa and corn were seeded the same day in May. Corn biomass for silage was harvested in October. Row spacing did not have effect on corn and alfalfa yield averaged across locations.  In Fargo, no differences in biomass yield were observed among row spacing, treatments, or the interaction of both. In Prosper, corn biomass yield was significantly different between the corn check and the corn-alfalfa intercrop, but only at 60-cm RS. At a 76-cm RS no significant differences were observed among the treatments.  Corn intercropped with alfalfa had 7.3 Mg ha^-1 less biomass yield than the corn alone. At 60-cm row spacing, the treatment with alfalfa-corn plus application of PHX was not different from corn alone (check). This indicates planting at 76 cm and applying PHX has potential.