No abstract

No abstract

No abstract

Winter wheat (Triticum aestivum L.) and perennial warm-season grasses are the primary forage resources for grazing yearling stocker cattle (Bos taurus) in the US Southern Great Plains (SGP). However, low nutritive value of perennial grasses during mid to late summer limits high rates of growth by stocker cattle. In response, there has been a continued search for plant materials with the potential to provide forage high in crude protein (CP) and digestibility during August through September. A broad range of under-utilized legume species that are grown as grain crops in Africa, India, and South and Central America may have some capacity to serve as high quality pasture or harvested forage in the SGP. However, any crop selection must account for limitations related to unpredictable summer rainfall amounts and patterns, and the frequent occurrence of prolonged drought. Further, any selection should not create water deficits for following winter wheat, the primary forage and grain crop in the region. This article summarizes a small subset of the broad range of underutilized grain legumes (pulses) which exist worldwide and soybean [Glycine max (L.) Merr.] that may have capacity to serve as high quality forage for late-summer grazing. Bringing these crops into forage-stocker production systems could improve the overall system effectiveness, in addition to providing other ecosystem services (e.g., ground cover, grain crops).

Fields are typically kept fallow after winter wheat (Triticum aestivum L.) grain harvest in the U.S. southern Great Plains (SGP). Introducing summer cover crops to the system could increase soil conservation and farm profitability if grazed. The objective of this research was to evaluate cover crops' forage yield, residue cover potential, weed suppression, and effect on wheat production. Monocultures and grass-legume mixtures of cover crops were established in mid-June of 2016 and 2017 near Chickasha and Perkins, OK. At 6 weeks after planting (WAP), three cutting regimes based on stubble height were used: severe (2.5 cm), recommended (legumes: 7.5 cm, grasses and mixtures: 15 cm), and no cutting. Cover crops regrowth was chemically terminated at 14 WAP; winter wheat was no-till seeded in mid-October; then harvested in early-June 2017 and 2018. Cultivar Triple Treat sorghum−sudangrass [Sorghum bicolor (L.) Moench × S. bicolor var. sudanese] and grass−legume mixtures showed the greatest available forage dry matter. Grasses and grass−legume mixtures had greater forage dry matter residue and weed suppression than legumes. Results indicated that exceeding 6.4 ± 1.2 Mg ha −1 of total dry matter (TDM) produced during the summer, a wheat grain yield penalty of −50.1 ± 15.8 kg ha −1 resulted for each increment of 1.0 Mg ha −1 of TDM produced. Also, a wheat protein content penalty of −1.9 ± 0.5 kg ha −1 resulted in each increment of 1.0 Mg ha −1 of TDM produced when exceeding to 5.7 ± 1.0 Mg ha −1 TDM threshold. Findings suggest N uptake by high-biomass grasses and mixtures might result in deficient water and N availability for wheat production.