Daniel Undersander and Shawn Conley, Agronomy, University of Wisconsin-Madison, Madison, WI
Objectives of this study were to determine the effect of small grain seeding rate on small grain forage and grain yield and to determine effect of several plant densities of oats, spring wheat and barley cover crops on alfalfa (Medicago sativa) establishment and on alfalfa yield in succeeding years. This study was conducted as a split-split plot design with the three small grains spring seeded at three rates over alfalfa (seeded at 13 kg ha-1 or 56 seeds m-2). The three small grains (Hazen Spring barley Hordeum vulgare, Esker Spring Oat Avena sativa and Glenn spring wheat Triticum aestivum) were seeded at three rates (108, 270, and 432 seeds m-1) and harvested either at the boot stage for forage or at grain maturity for grain. The study was seeded at four locations in Wisconsin in each of two years. Alfalfa yield was measured the year after establishment.
Forage yield increased with higher seeding rates above the base rate: for barley 11 and 24%, for oats 23 and 38%, and for wheat 22 and 31%. The percentage grain also increased above the lowest seeding rate: for barley 23 and 33%, for oats 24 and 31%, and for wheat 10 and 20%). Harvesting the small grain as forage or grain had no impact on yield of alfalfa seeded underneath the small grain in the year following seeding (first production year).