Grazing Termination Dates of Summer-Dormant Flecha Tall Fescue

Summer-dormant, Mediterranean-type tall fescue (Festuca arundiancea Schreb.) has potential to replace summer-active, Continental-type tall fescue and trad-itional, annual small grain graze-out systems in the Southern Great Plains region of the USA. This region is characterized by severe water deficits accompanied by extreme heat in summer, and by relatively mild, rainy winters (Malinowski et al. 2009). Although the climate of the southern Great Plains is different from the Mediterranean climate, the temperature and precipitation patterns during summer are historically similar. However, in the past decade, the bimodal precipitation pattern with peaks in May and September has become highly unpredictable, resulting in delayed planting of small grains in autumn and lack of winter forage for grazing livestock (Malinowski et al. 2009). As a perennial forage crop, summer-dormant tall fescue provides a source of forage during the winter months when warm-season grasses are dormant, reducing pasture establishment costs, soil erosion, and the time and labor associated with annual forage systems (Kindiger and Conley 2002; Beck et al. 2008; Islam et al. 2011). Replacing summer-active with summer-dormant cool-season grasses can provide some resilience in the forage systems to extreme seasonal precipitation and temperature patterns (Clark and Harris 2009; Malinowski et al. 2005). These conditions, combined with relatively mild winters, allow summer-dormant tall fescue to be better adapted and more persistent in the southern Great Plains than traditional, summer-active types of tall fescue and other cool-season perennial grasses (Hopkins and Bhamidimarri, 2009; Malinowski et al. 2009). However there are no best-management practices that address the timing of grazing cessation as it relates to summer-dormant tall fescue stand persistence and animal production. The objectives of this study were to determine the effects of four grazing termination dates on endophyte-free ‘Flecha’ summer-dormant tall fescue forage production, animal production (average daily gain [ADG], gain, and grazing days), and tall fescue persistence (% stand and root mass)

Endophyte Status in Summer-Dormant Tall Fescue in the Southern Great Plains of USA

Non-toxic fungal endophytes provide persistence-related benefits to summer-active, continental-type tall fescue (Festuca arundinacea Schreb.), as well as reduced animal toxicosis compared to toxic endophytes. However, the benefits of fungal endophytes to summer-dormant, Mediterranean-type tall fescue persistence or production are unclear. Summer-dormant tall fescue has potential to replace traditional, annual small grain graze-out systems in the Southern Great Plains region of the USA. This region is characterized by severe water deficits accompanied by extreme heat in summer, and by relatively mild, rainy winters (Malinowski et al. 2009). Summer-active tall fescues are better suited to high rainfall areas (\u3e 900 mm annual average rainfall (AAR)) east of the 97° longitudinal meridian, while summer-dormant tall fescues are best adapted to lower rainfall areas (600 to 900 mm AAR) between the 97° and 99° longitudinal meridian (Butler et al. 2011). The objective of this field study was to determine the effects of the ‘novel’ endophyte strain AR542 on persistence of summer-dormant tall fescue ‘Flecha’ in the Southern Great Plains of the USA. Two field experiments were conducted to evaluate the effect of the novel endophyte AR542 on the survival of Flecha

Herbage and Seed From Texan Native Perennial Herbaceous Legumes

Native seed mixes for rangeland seeding, prairie restoration, or cultivated pasture can benefit from a greater variety of forbs that more closely reflect the original vegetation of the southern Great Plains. Fifteen native, perennial herbaceous legumes were collected in central Texas and evaluated for herbage production, mineral content, and fiber concentration of established plants in research plots over 2 years. Downy milk-pea (Galactia volubilis [L.] Britton) was productive, regardless of rainfall, whereas prairie acacia (Acacia angustissima [Mill.] Kuntze var. hirta [Nutt.] B.L. Rob.) and Illinois bundle-flower (Desmanthus illinoensis [Michx.] MacMill. Ex. B.L. Rob. Fernald) out-yielded others in year 3 when rainfall was the greatest. Herbage crude protein averaged approximately 100 g kg-1 for bush-clovers (Lespedeza spp.) compared to bundle-flowers (Desmanthus spp.), which exceeded 200 g kg-1; the latter also was high in herbage phosphorus. Herbage neutral detergent fiber ranged from 300 to more than 500 g kg-1, acid detergent fiber ranged from 140 to 360 g kg-1, and acid detergent lignin ranged from 36 to 140 g kg-1, a wide range from which to select if animal nutrition is a primary criterion. Seed production was evaluated within a subset of 8 entries submitted to periodic herbage removal or left intact throughout the season. Three bundle-flowers yielded the greatest mass and seed number, but were negatively affected by harvest, unlike prairie acacia. Herbage and seed characteristics indicate there are promising perennial herbaceous legumes in the southern Great Plains that can be included in native seed mixes.  The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 2020Legacy DOIs that must be preserved: 10.2458/azu_rangelands_v58i6_interrant

Estimation of Biomass and Canopy Height in Bermudagrass, Alfalfa, and Wheat Using Ultrasonic, Laser, and Spectral Sensors

Non-destructive biomass estimation of vegetation has been performed via remote sensing as well as physical measurements. An effective method for estimating biomass must have accuracy comparable to the accepted standard of destructive removal. Estimation or measurement of height is commonly employed to create a relationship between height and mass. This study examined several types of ground-based mobile sensing strategies for forage biomass estimation. Forage production experiments consisting of alfalfa (Medicago sativa L.), bermudagrass [Cynodon dactylon (L.) Pers.], and wheat (Triticum aestivum L.) were employed to examine sensor biomass estimation (laser, ultrasonic, and spectral) as compared to physical measurements (plate meter and meter stick) and the traditional harvest method (clipping). Predictive models were constructed via partial least squares regression and modeled estimates were compared to the physically measured biomass. Least significant difference separated mean estimates were examined to evaluate differences in the physical measurements and sensor estimates for canopy height and biomass. Differences between methods were minimal (average percent error of 11.2% for difference between predicted values versus machine and quadrat harvested biomass values (1.64 and 4.91 t·ha−1, respectively), except at the lowest measured biomass (average percent error of 89% for harvester and quad harvested biomass < 0.79 t·ha−1) and greatest measured biomass (average percent error of 18% for harvester and quad harvested biomass >6.4 t·ha−1). These data suggest that using mobile sensor-based biomass estimation models could be an effective alternative to the traditional clipping method for rapid, accurate in-field biomass estimation

Germination in Cool-Season Forage Grasses under a Range of Temperatures

WOS: 000404483500058Temperature plays a primary role in seed germination, and germination under a wide range of temperatures can promote early seedling emergence and stand establishment. The objective of this growth chamber experiment was to determine the effects of temperature (5-35 degrees C) on the germination of eight species using 6 annual and 14 perennial cool-season grass lots. The greatest germination of annual and perennial cool-season grasses occurred at 20 and 15 degrees C, respectively. Germination of oat (Avena sativa L.) was typically greatest at 10 to 20 degrees C, whereas rye (Secale cereale L.) germination was generally greatest at 5 to 20 degrees C and annual ryegrass (Lolium multiflorum Lam.) germination was greatest at 10 to 30 degrees C. Germination of orchardgrass (Dactylis glomerata L.) and hardinggrass (Phalaris aquatica L.) was greatest at 15 to 20 degrees C. Germination of tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] varied by type: summer-active tall fescue had optimal germination between 15 and 25 degrees C but summer-dormant tall fescue had optimal germination between 10 and 20 degrees C, except for 'NFTF 1800E-', which was more sensitive to high temperatures (>5 degrees C). On the basis of these findings, the seeding rates of rye, oat, orchardgrass, hardinggrass, and tall fescue should be increased by similar to 30% if planted in early September rather than late September to account for the reduction in germination; summer-dormant tall fescue should be planted 2 to 3 wk later (1-15 October) than summer-active types (early September) in the southern Great Plains

Temperature Affects the Germination of Forage Legume Seeds

WOS: 000346571900045Temperature, in addition to moisture, oxygen, and light, plays an important role in seed germination. Early seedling emergence and stand establishment can be promoted by germination of seeds under a wide range of temperatures; therefore, it is desirable for commercial legume wcultivars to germinate over a range of temperatures. The objective of this growth chamber experiment was to determine the effects of temperature on seed germination of seven annual warm-season and 11 annual cool-season legumes. Greatest germination of warm-season and cool-season legumes occurred at 25 and 20 degrees C, respectively. Germination of warm-season legumes tended to be maximized at 25 degrees C, while cool-season legume germination was greatest from 10 to 25 degrees C. Cultivars 'Rio Verde' lablab [Lablab purpureus (L.) Sweet] and 'Whitetail Thicket' soybean [Glycine soja Siebold and Zucc. x Glycine max (L.) Merr.] had greater germination than the other entries at 35 degrees C, indicating their potential for use in warmer climates or in delayed planting dates. Additionally, Whitetail Thicket had the greatest germination of summer legume entries at 10 degrees C. The germination of 'Dixie' crimson clover (Trifolium incarnatum L.), PI 419238 button medic [Medicago orbicularis (L.) All.], and 600RR and 'Bulldog 505' alfalfas (Medicago sativa L.) were less sensitive to temperature than the other cool-season legume entries. Germination of 'Devine' little burr medic (Medicago minima L.), 'Armadillo' burr medic (Medicago polymorpha L.), and 'Apache' arrowleaf clover (Trifolium vesiculosum Savi) were severely reduced at temperatures above 30 degrees C