Comparing Productivity and Efficiency of Grass-Only and Grass-Legume Beef Stocker Grazing Systems in the Southern High Plains.

The imminent depletion of the Ogallala Aquifer demands innovative alternatives to prevent dramatic losses of income when water levels are insufficient for irrigated row-crop production in the Southern High Plains. With the goal to optimize sustainability and productivity with pasture-based beef stocker systems, a grass-legume (GL) pasture system employing regionally novel forages and grazing techniques was compared to a previously examined grass-only (GO) warm-season pasture system. Since protein is often the limiting factor in improving performance of stockers grazing warm-season perennial pastures, higher gains are expected with strategic inclusion of legumes such as alfalfa (Medicago sativa L.). Alfalfa was managed as a protein bank so that a limited water resource was concentrated on a small area to produce a high-quality supplement for poorer-quality grass pastures. Inclusion of legumes increased stocker gain achieved per hectare in all three years (P < 0.01). Longer, less frequent rotations into the protein bank further magnified this difference between treatments in year 2 and 3. There was no significant difference in the irrigation applied to the GO and GL systems when averaged across the three trial years (P = 0.80). Finally, the water footprint of the GL system was lower than the GO system in all three years (P < 0.01). The forage-livestock systems created in this research will serve as alternatives for producers transitioning from irrigated row-crops into more resource-sustaining systems.