Submitted to: Grass and Forage Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2007
Publication Date: 2/9/2008
Citation: Bartholomew, P.W., Williams, R.D. 2008. Seeding cool-season grasses into unimproved warm-season pasture. Grass and Forage Science. 63:94-106.
Interpretive Summary: Grazed pasture is the cheapest form of feed for livestock, but in the Southern Plains pasture growth ceases for nearly six months during fall and winter each year because of low temperatures. Traditionally farmers have made hay or have planted wheat for winter grazing to solve the seasonal feed shortage. However, many small and limited-resource farmers do not have easy access to the equipment needed for hay making or for cultivation and planting of wheat, so they have to purchase feed for prolonged periods each year. This expenditure can severely reduce profits from small-scale livestock businesses. An improved winter-feeding strategy might be to plant cool-season forages that grow later in the fall and earlier in the spring than natural or sown warm-season pastures. This would allow animals to graze for a longer period of the year and reduce the need for purchased feed. If the crops sown are perennials the need for annual replanting, and its associated cost, can be avoided. The production of five perennial and one annual cool-season grasses was measured over four years on low-productivity land typical of small and resource-limited farms. Grasses were established by tilling warm-season pasture and sowing seed conventionally, or by no-till seeding either into existing warm-season pasture or into the stubble of a crop of Korean lespedeza, a warm-season legume. Cool-season grasses established slightly better and produced more forage when sown following Korean lespedeza or into tilled ground than when they were no-till drilled into uncultivated (but dormant) warm-season pasture. However, tillage severely damaged the existing pasture, and the result of this was to reduce the combined year-round production of cool- and warm-season pasture. The best year-round forage production was found when Italian ryegrass (an annual grass) was no-till sown into existing pasture. No-till seeding of cool-season grasses into dormant warm-season pasture can increase cool-season feed supply on small farms without the risk of reducing year-round production because of damage to warm-season pasture.
Technical Abstract: Limited availability of forage during the cool season creates a feed-supply problem for livestock producers throughout the southern Great Plains of the USA, and particularly on small farms where resource constraints limit possible mitigating strategies. Cool-season grasses were sown in clean-tilled ground or, no-till drilled into stubble of Korean lespedeza [Kummerowia stipulacea (Maxim.) Makino] or into dormant warm-season pasture. The production of mixtures of cool and warm-season forage species was measured to test their potential for increasing cool-season forage production in a low-input pasture environment. Only mixtures containing Italian ryegrass (Lolium multiflorum Lam) produced greater year-round yields than undisturbed warm-season pasture with all establishment methods. Tall fescue (Festuca arundinacea Schreb) sown in lespedeza also increased annual yield. Cool-season grass no-till seeded into existing warm-season pasture produced an average 0.61 kg net gain in year-round forage production for each 1.0 kg of cool-season grass produced. Sowing into lespedeza stubble, or into clean-tilled ground, required 700 or 1400 kg ha-1, respectively, of cool-season production before the year-round yield of each treatment equaled that of undisturbed warm-season pasture. Productive stands of perennial cool-season grass were not sustained beyond two growing seasons with tall wheatgrass (Elytrigia elongata (Host) Nevski), intermediate wheatgrass (E. intermedia (Host) Nevski) and a creeping wheatgrass (E. repens L.) x bluebunch wheatgrass (Pseudoroegneria spicata (Pursh)) hybrid. Lack of persistence and low productivity limit the usefulness of cool-season perennial grasses for overseeding unimproved warm-season pasture in the southern Great Plains.