|Skinner, J. Vaughn|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2007
Publication Date: 6/23/2008
Citation: Gunsaulis, J.L., Coblentz, W.K., Ogden, R.K., Bacon, R.K., Coffey, K.P., Hubbell, D.S., Skinner, J., Akins, M.S., Caldwell, J.D., Lusby, K.S. 2008. Fall Growth Potential of Cereal Grain Forages in Northern Arkansas. Agronomy Journal. 100:1112-1123. Interpretive Summary: Without the need to produce a grain crop, numerous options exist for clean-tilled cereal grains that will likely exceed the fall forage dry matter production of a traditional wheat monoculture. In northern Arkansas, coupling a relatively early planting date with selection of cultivars that typically exhibit at least some stem elongation will maximize fall yield of dry matter. Unfortunately, this production advantage is coupled with increased sensitivity to freeze damage or winterkill. Therefore, selection of these cultivars should be in response to very specific producer objectives, such as maximizing weight gains of a specific group or class of animals during the fall and early winter, or to provide emergency forage following summer drought. Selection of a wheat or rye cultivar that remains strictly vegetative throughout the fall becomes much more attractive when producer goals are general, and include a broader time interval of potential use by one or multiple livestock groups or classes. These results also suggest some additional work may be warranted to evaluate systems utilizing multiple species and/or cultivars in combination, particularly when they are established independently, which could improve both season-long forage production and distribution.
Technical Abstract: In Arkansas, producers utilizing cereal grains as fall forage for weaned calves usually do not harvest a grain crop the following summer. This contrasts sharply from practices observed commonly in neighboring Oklahoma, and allows for much wider latitude with respect to management strategies, especially those that may optimize fall growth. Our objectives were to evaluate eight diverse cultivars of wheat (Triticum aestivum L.), oat (Avena sativa L.), rye (Secale cereale L.), and triticale (X Triticosecale Wittmack) specifically for their potential to accumulate forage DM during fall. All cultivars were drilled into prepared seedbeds at Fayetteville and Batesville during early September of 2004 and 2005, and harvested at two-week intervals from mid-October through December. Cultivar x harvest date interactions or tendencies for interaction (P ? 0.069) were observed for all combinations of site and year. For Fayetteville 2004, triticale and oat cultivars accumulated DM in a cubic (P ? 0.040) pattern, most likely because growing tillers exhibited stem elongation, and were then susceptible to freeze damage in late December. Generally, wheat and rye cultivars accumulated DM in less complex patterns over harvest dates, but the maximum numerical yield for any wheat cultivar was only 2,554 kg ha-1 compared to 4661 kg ha-1 for oat. For Batesville 2004 and Fayetteville 2005, DM yields for cultivars ranked similarly, but respective overall mean yields (490 and 988 kg ha-1) were only 25 and 50% of those for Fayetteville 2004 (1960 kg ha-1), largely due to drought. For Batesville 2005, favorable growing conditions coupled with a sharp mid-November freeze (-7oC), created yield responses that were unique relative to other site-years. Yield of DM increased quadratically (P ? 0.002) for wheat, rye, and triticale cultivars throughout the fall sampling period, accumulating a mean maximum yield of 4148 kg ha-1 on the final harvest date. In contrast, oat cultivars were especially sensitive to freezing temperatures in November, and averaged only 2484 kg ha-1 on the final harvest date. Producers requiring high-quality forage in the fall and winter can usually improve fall production by using oat or other species that exhibit some stem elongation when planted in early September; however, this trait may increase freeze damage, thereby making winter survival problematic.