Annual medics (Medicago spp.) have potential to be important forage legumes in the southern Great Plains of the United States. Currently there are no commercial medic species‐specific rhizobia strains identified for their inoculation. However, commercially available alfalfa (Medicago sativa L.) inoculants may be effective at successfully nodulating annual medics. The objective of this study was to determine the relevant symbiotic rhizobial partner in association with seven annual medics. A greenhouse experiment arranged in three replications of a randomized complete block design quantified rhizobium effectiveness index and shoot and root dry matter (DM) of Medicago arabica (L.) Huds., Medicago lupulina L., Medicago minima (L.) Bartal., Medicago orbicularis (L.) Bartal., Medicago polymorpha L., Medicago rigidula (L.) All., and Medicago rigiduloides E. Small when inoculated with five Sinorhizobium spp. strains (M2, M49, Nitragin A, Nitragin N [a blend of three isolates], and WSM1115) and an untreated control (UTC). Strain M49 was the only strain that effectively nodulated M. rigiduloides, while Nitragin A commercial alfalfa strain was only effective on M. rigidula. Inoculants M2, Nitragin N, and WSM1115 were able to effectively nodulate M. polymorpha, M. arabica, M. minima, and M. orbicularis. To a lesser extent, M. lupulina, M. minima, and M. orbicularis were also effectively nodulated by Nitragin A alfalfa strain. These data indicate that there are differences in rhizobia specificity of annual medic species, and further research is warranted to improve nodulation of these legumes in the field.

Mixtures of cool‐season perennial grasses and perennial legumes in pastures have potential to improve forage production, seasonal distribution, and animal performance. Two experiments were initiated at Vernon, TX (Wichita clay loam), Vashti, TX (Anocon loam), or Ardmore, OK (Durant loam), evaluating the effects of various row orientations on the establishment of alfalfa (Medicago sativa L. cv. Bulldog 505) and tall fescue [Schedonorus arundinaceus (Schreb.) Dumort cv. Flecha]. Row orientations in experiment I included alternating drill passes (5.6 ft), alternating drill rows (7.5 inch), and binary mixture of alfalfa and tall fescue planted in the same drill row. Row orientations in experiment II included perpendicular rows, alternating drill rows, and a combination of both alternating and perpendicular drill row orientations. In experiment I, both alternating drill passes and alternating drill rows resulted in successful establishment, while the binary mixture resulted in excessive competition. In experiment II, both alternating drill rows and the combination of alternating and perpendicular row orientation treatments generally resulted in successful establishment and adequate composition of alfalfa and tall fescue. The combination of alternating and perpendicular planting orientation offers best potential to minimize preferential grazing while maintaining adequate stand density and persistence in the southern Great Plains.

Core Ideas Switchgrass has potential for renewable biofuel production. It is productive under nutrient‐ or water‐limited environments. It can be no‐till planted on lands that are susceptible to erosion. Switchgrass (Panicum virgatum L.) is a native, long‐lived, warm‐season perennial grass that is well adapted, has potential for biofuel production, and can improve soil chemical and physical properties. It can be difficult to establish, but it can be productive in marginally productive or difficult to cultivate lands, and its root system can aid in soil conservation. The objectives of this 2‐year field experiment were to determine the effects of seedbed preparation (burning, mowing, or tilling) and planting depth (0.25, 0.5, or 1.0 inches) on the establishment and yield of ‘EG 1101’ switchgrass. Planting between 0.25 and 0.5 inch generally resulted in more seedlings and greater stand percent and yield than 1.0‐inch depth. Tilling generally resulted in more initial seedlings at 30 days after planting (DAP) than no‐till with burning or mowing, but stand percent (150 DAP) and yield (postfrost) were not affected by seedbed preparation later in the growing season. However, all seedbed preparations and planting depths produced successful switchgrass stands of >1 seedling/ft2 and ≥50% stands. Producers planting on land susceptible to erosion could consider no‐till planting after burning or mowing in order to reduce soil erosion and promote better soil structure and fertility without any loss in switchgrass productivity.

Tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.] is a perennial cool‐season grass in which improved freeze tolerance could result in greater winterhardiness and persistence. Our objective was to evaluate survival and freeze‐tolerance thresholds of ‘Flecha’ summer‐dormant (SD) and ‘Texoma Max QII’ summer‐active (SA) tall fescue at seedling (1–2 leaves) and tillered (5–6 leaves) growth stages using controlled environment freezing chambers. Target temperatures ranged from 0 to −9 °C (seedlings) and 0 to −12 °C (tillered plants). Predicted lethal temperature at which 50% mortality occurs (LT50) was −5.7 and −5.5 °C for SA and SD seedlings, respectively, and −6.0 and −5.7 °C for SA and SD tillered plants, respectively. Based on these results, a controlled temperature chamber appears to be a useful tool for plant breeders when evaluating survival and freeze tolerance of SA and SD tall fescue germplasm at seedling and tillered growth stages.

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