Perennial Grass Species Yield in Dryland and Limited Irrigation Production in the Semi-Arid Southern High Plains.

As Ogallala irrigation levels decline the Southern High Plains of Texas, producers concede that irrigation levels will no longer sustain popular crop options such as corn, cotton, and wheat at satisfactory yield levels.  Perennial grass pastures offer a low-input alternative to irrigated crops under irrigation as well as a suitable alternative for dryland cropping systems.  The objective was to evaluate twelve species of perennial grass for forage production with zero, low, and moderate irrigation levels.  The trial was initiated in 2006 near Lockney, TX using old world bluestems (3), buffalograss, blue grama, sideoats grama, Alamo switchgrass, Kleingrass, Indiangrass, and Bermuda grass (2) with the three irrigation levels overlaying the species.  Forage harvests were conducted twice per year, weighed, and a subsample saved for forage quality analyses.  Multi-year average forage yields demonstrated that Alamo switchgrass yielded 5.8 tons DM per hectare with no irrigation, and 7.0 tons ha^-1 at the moderate level of irrigation, which averaged 25 cm over the year.  Old world bluestems (WWB-Dahl, Spar, and Caucasian) yielded near 5.0 tons ha^-1 without irrigation.  Native range species like blue grama and sideoats grama, which are highly palatable to livestock, yielded 40-50% less than switchgrass.  Bermudagrass yielded about 1 ton/hectare less than the old world bluestems.  Producers are encouraged to avoid so-called ‘wonder’ grasses but focus on proven varieties with regional adaptation to achieve satisfactory results.  This is especially important as the water irrigation resource from the Ogallala steadily declines.