76 Evaluating Nitrogen Management Strategies to Improve Southern Bermudagrass Grazing Systems

Abstract Bermudagrass (Cynodon dactylon) is one of the most common perennial warm-season forage crops grown in the South. While prominent in the region bermudagrass management requires large amounts of fertility and forage quality is moderate at best. Incorporating a legume into bermudagrass pastures could serve as an alternative to the necessary applications of synthetic N, while also improving the nutritive value of the forage base. A two-year grazing evaluation was conducted from May-Sept. 2018 (Y1) and May-Aug. 2019 (Y2) at the University of Georgia Tifton Campus in Tifton, Georgia, to compare concurring production of alfalfa/bermudagrass mixed pastures (BGA) with bermudagrass monoculture pastures with (BGN) or without (BGZ) the application of synthetic nitrogen. The experimental design was a randomized complete block with three treatments and two replications. All paddocks were evaluated pre and post grazing event for herbage availability, botanical composition, forage species competitiveness, and nutritive value. Paddocks (0.8-ha) were rotationally grazed using put and take management with stocker steers (Y1 BW=195.9±22.9 kg; Y2 BW=228.5±30.0 kg), two testers per treatment. Steers were weighed at initiation, conclusion, and on a 28–30 day interval for calculation of ADG and gain/ha. Statistical analysis was conducted using the PROC MIXED procedure of SAS. Despite significant drought in Y2, year did not affect total gain/ha, however treatment did (P = 0.04), such that BGA was highest (383.6±35.1 kg/ha), and BGN and BGZ were not different (261.2±35.1 kg/ha and 239.0±35.1 kg/ha, respectively). This is likely due to the lower stocking density and inclusion of high-quality volunteer annual grasses in BGZ treatments which allowed for selective grazing. These data suggest that rotationally grazing alfalfa/bermudagrass mixtures can result in a higher gain/ha, than bermudagrass pastures that are supplemented with or without synthetic N in the South.

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77 Evaluating Nitrogen Management Strategies to Improve Southern Bermudagrass Grazing Systems

Journal of Animal Science ◽

10.1093/jas/skz397.040 ◽

2020 ◽

Vol 98 (Supplement_2) ◽

pp. 18-18

Author(s):

Justin C Burt ◽

Jennifer J Tucker ◽

Lisa Baxter

Keyword(s):

Nutritive Value ◽

Cynodon Dactylon ◽

Management Strategies ◽

Stocking Density ◽

Warm Season ◽

The South ◽

Forage Crops ◽

University Of Georgia ◽

Annual Grasses ◽

The University

Abstract Bermudagrass (Cynodon dactylon) is one of the most common perennial warm-season forage crops grown in the South. While prominent in the region bermudagrass management requires large amounts of fertility and forage quality is moderate at best. Incorporating a legume into bermudagrass pastures could serve as an alternative to the necessary applications of synthetic N, while also improving the nutritive value of the forage base. A two-year grazing evaluation was conducted from May-Sept. 2018 (Y1) and May-Aug. 2019 (Y2) at the University of Georgia Tifton Campus in Tifton, Georgia, to compare concurring production of alfalfa/bermudagrass mixed pastures (BGA) with bermudagrass monoculture pastures with (BGN) or without (BGZ) the application of synthetic nitrogen. The experimental design was a randomized complete block with three treatments and two replications. All paddocks were evaluated pre and post grazing event for herbage availability, botanical composition, forage species competitiveness, and nutritive value. Paddocks (0.8-ha) were rotationally grazed using put and take management with stocker steers (Y1 BW=195.9±22.9 kg; Y2 BW=228.5±30.0 kg), two testers per treatment. Steers were weighed at initiation, conclusion, and on a 28–30 day interval for calculation of ADG and gain/ha. Statistical analysis was conducted using the PROC MIXED procedure of SAS. Despite significant drought in Y2, year did not affect total gain/ha; however, treatment did (P = 0.04), such that BGA was highest (383.6±35.1 kg/ha), and BGN and BGZ were not different (261.2±35.1 kg/ha and 239.0±35.1 kg/ha, respectively). This is likely due to the lower stocking density and inclusion of high-quality volunteer annual grasses in BGZ treatments which allowed for selective grazing. These data suggest that rotationally grazing alfalfa/bermudagrass mixtures can result in a higher gain/ha, than bermudagrass pastures that are supplemented with or without synthetic N in the South.

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28 Three-year evaluation of yield and nutritive value of tifton-85 bermudagrass and tifton-85 bermudagrass-alfalfa mixtures produced as baleage in the southeast

Journal of Animal Science ◽

10.1093/jas/skz053.048 ◽

2019 ◽

Vol 97 (Supplement_1) ◽

pp. 21-22

Author(s):

Taylor J Hendricks ◽

Jennifer J Tucker ◽

Dennis W Hancock ◽

Lawton Stewart ◽

Jacob R Segers

Keyword(s):

Nutritive Value ◽

Near Infrared ◽

Cynodon Dactylon ◽

N Fertilization ◽

Forage Yield ◽

Botanical Composition ◽

Value Analysis ◽

University Of Georgia ◽

The University

Abstract Interseeding a legume, such as alfalfa (Medicago sativa), into bermudagrass (Cynodon dactylon) for baleage production can improve forage quality, reduce supplementation needs, and minimize production losses. The objective of this research was to compare the nutritive value and yield of bermudagrass with and without interseeded alfalfa when produced as baleage. This study was conducted at the University of Georgia Coastal Plain Experiment Station in Tifton, GA, on an established field of ‘Tifton 85’ (T85) bermudagrass. Ten 0.2-ha plots were randomly assigned to either T85+N or T85 interseeded with ‘Bulldog 805’ alfalfa (T85+Alf). T85+N received N fertilization (84 kg N/ ha) four times each growing season. Plots were harvested at early bloom stage every 28 to 35 days from 2016 to 2018, baled at 40–60% moisture, and individually wrapped. At each harvest, plots were evaluated for botanical composition and forage yield, and bales were sampled prior to wrapping for nutritive value analysis. Plots were also evaluated for botanical composition using the point-transect method 10 days post-harvest. Data were analyzed using mixed models and least significant differences at α = 0.05. Although seasonal yields were greater in the T85+N during year 1, alfalfa-bermudagrass plots produced at least one additional harvest each season of the study, and on average 8 cuttings per season each year following establishment. Ultimately this contributed to greater (P < 0.0001) cumulative yield in the alfalfa-bermudagrass treatment (34,783 vs. 25,608 kg/ha, respectively). Analyses of nutritive value through near-infrared spectroscopy (NIR) show that CP and in-vitro true digestibility (IVTD) were greater (P = 0.005 and P = 0.034, respectively) in the alfalfa-bermudagrass treatment than the bermudagrass-only treatment (14.0 vs 11.4% CP and 66.7 vs. 60.2% IVTD, respectively). Improvements in seasonal yield and nutritive value makes bermudagrass interseeded with alfalfa a viable option for baleage producers in the Southeast.

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Incorporating Alfalfa into Warm-season Grass Systems in the Southeast

Journal of Animal Science ◽

10.1093/jas/skab096.064 ◽

2021 ◽

Vol 99 (Supplement_2) ◽

pp. 35-36

Author(s):

Jennifer J Tucker

Keyword(s):

Management Strategies ◽

Forage Quality ◽

Stocking Density ◽

Warm Season ◽

Growing Season ◽

Great Success ◽

Supplemental Feed ◽

University Of Georgia ◽

Warm Season Grass ◽

Management Recommendations

Abstract Bermudagrass is the primary warm season perennial forage crop grown in the Southeast (~20 million acres) for livestock and forage operations. While prominent in the region, bermudagrass requires large amounts of fertility and forage quality is moderate relative to other options. There has been great success and a growing interest in interseeding alfalfa into existing bermudagrass stands in the region. This combination eliminates the need for nitrogen fertilization, increases relative forage quality (RFQ) better meeting the nutritional needs of livestock, and decreases the need for supplemental feed. In recent years, research evaluations have been conducted across the Southeast to evaluate the use of alfalfa when incorporated into warm-season grass forage systems under various management strategies. Three projects conducted from 2016–2020 at the University of Georgia Tifton campus evaluated ‘Bulldog 805’ alfalfa interseeded into Tifton-85 bermudagrass (1) when harvested as baleage, (2) under grazing management and(3) in a clipping study to better define defoliation management recommendations. Overall findings from this work observed that alfalfa-bermudagrass mixtures provide greater seasonal herbage accumulation, extend the growing season by three to four months annually, and increase forage DM digestibility and CP compared to bermudagrass alone. Steers on ABG managed under rotational stocking had greater total gain/ha (~%33 increase) due to a higher stocking density throughout the growing season than a bermudagrass monoculture. Results indicate that interseeding alfalfa into bermudagrass is a viable option for southeastern forage systems and can be an effective way to improve forage quality, extend the grazing season, and reduce the need for additional supplementation when fed to livestock.

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102 Three-year evaluation of yield and nutritive value of Tifton-85 bermudagrass and Tifton-85 bermudagrass-alfalfa mixtures produced as baleage in the Southeast

Journal of Animal Science ◽

10.1093/jas/skz053.081 ◽

2019 ◽

Vol 97 (Supplement_1) ◽

pp. 36-36

Author(s):

Taylor J Hendricks ◽

Jennifer J Tucker ◽

Dennis W Hancock ◽

Lawton Stewart ◽

Jacob R Segers

Keyword(s):

Nutritive Value ◽

Near Infrared ◽

Cynodon Dactylon ◽

N Fertilization ◽

Forage Yield ◽

Botanical Composition ◽

Value Analysis ◽

University Of Georgia ◽

The University

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Modification of the summative equation to estimate daily total digestible nutrients for bermudagrass pasture

Journal of Animal Science ◽

10.1093/jas/skaa354 ◽

2020 ◽

Vol 98 (11) ◽

Author(s):

Prem Woli ◽

Francis M Rouquette ◽

Charles R Long ◽

Luis O Tedeschi ◽

Guillermo Scaglia

Keyword(s):

Nutritive Value ◽

Cynodon Dactylon ◽

Perennial Grass ◽

Warm Season ◽

Neutral Detergent Fiber ◽

Systematic Bias ◽

Grazing Season ◽

Nutritive Values ◽

Plant Maturity ◽

Daily Total

Abstract In forage-animal nutrition modeling, diet energy is estimated mainly from the forage total digestible nutrients (TDN). As digestibility trials are expensive, TDN is usually estimated using summative equations. Early summative equations assumed a fixed coefficient to compute digestible fiber using the lignin-to-neutral detergent fiber (NDF) ratio. Subsequently, a structural coefficient (φ) was added to the summative equations to reflect an association between lignin and cell wall components. Additional modifications to the summative equations assumed a constant φ value, and they have been used as a standard method by many commercial laboratories and scientists. For feeds with nutritive values that do not change much over time, a constant φ value may suffice. However, for forages with nutritive values that keep changing during the grazing season owing to changes in weather and plant maturity, a constant φ value may add a systematic bias to prediction because it is associated with the variable lignin-to-NDF ratio. In this study, we developed a model to estimate φ as a function of the day of the year by using the daily TDN values of bermudagrass [Cynodon dactylon (L.) Pers.], a popular warm-season perennial grass in the southern United States. The variable φ model was evaluated by using it in the TDN equation and comparing the estimated values with the observed ones obtained from several locations. Values of the various measures of fit used—the Willmott index (WI), the modeling efficiency (ME), R2, root mean square error (RMSE), and percent error (PE)—showed that using the variable φ vis-à-vis the constant φ improved the TDN equation significantly. The WI, ME, R2, RMSE, and PE values of 0.94, 0.80, 0.80, 2.5, and 4.7, respectively, indicated that the TDN equation with the variable φ model was able to mimic the observed values of TDN satisfactorily. Unlike the constant φ, the variable φ predicted more closely the forage nutritive value throughout the grazing season. The variable φ model may be useful to forage-beef modeling in accurately reflecting the impacts of plant maturity and weather on daily forage nutritive value and animal performance.

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Yield, Yield Distribution, and Nutritive Value of Intensively Managed Warm-Season Annual Grasses

Agronomy Journal ◽

10.2134/agronj2001.1257 ◽

2001 ◽

Vol 93 (6) ◽

pp. 1257-1262 ◽

Cited By ~ 22

Author(s):

Renato S. Fontaneli ◽

Lynn E. Sollenberger ◽

Charles R. Staples

Keyword(s):

Nutritive Value ◽

Warm Season ◽

Yield Distribution ◽

Annual Grasses ◽

Intensively Managed

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Stocker performance and production in mixed tall fescue–bermudagrass pastures of the Southern Piedmont USA

Renewable Agriculture and Food Systems ◽

10.1017/s1742170512000105 ◽

2012 ◽

Vol 28 (2) ◽

pp. 160-172 ◽

Cited By ~ 4

Author(s):

Alan J. Franzluebbers ◽

John A. Stuedemann ◽

Dwight H. Seman

Keyword(s):

Tall Fescue ◽

Cynodon Dactylon ◽

Stocking Density ◽

Warm Season ◽

Grazing Pressure ◽

Pasture Management ◽

Coastal Bermudagrass ◽

Forage Utilization ◽

Environmental Goals ◽

Grazing Pressures

AbstractStocker performance and production from mixed cool- and warm-season perennial pastures are important determinants of agricultural sustainability that can be influenced by management. We evaluated the factorial combination of three sources of nutrient application (inorganic only, organic+inorganic combination, and organic only) and two forage utilization regimes [low grazing pressure (LGP) and high grazing pressure (HGP)] on steer stocking density and rate, performance and production during 7 years of pasture management {tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] overseeded into existing Coastal bermudagrass [Cynodon dactylon (L.) Pers.] sod} on a Typic Kanhapludult in Georgia, USA. Nutrient source had few major impacts on responses, except for lower animal performance with organic fertilization (broiler litter) than with organic+inorganic and inorganic only fertilization, especially with LGP. Seasonal changes in stocking weight and rate occurred, not only as expected due to environmental conditions and dominant forage species present, but that also counteracted expected differences imposed by grazing pressure; signaling negative feedback of HGP on forage productivity. Steer performance was greatest in spring and summer under both grazing pressures, but was significantly reduced with increasing grazing pressure in the autumn and winter due to low forage availability. Across years, steer gainha−1 (863kgha−1) was not different between grazing pressures, but gainha−1 declined with time under HGP and was stable with time under LGP. Reducing grazing pressure to a moderate level can lead to equivalent steer production as HGP, and would likely contribute to a more sustainable balance among production, socio-economic and environmental goals. These multi-year results will help cattle producers in warm, moist climates design and implement more sustainable grazing systems.

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Green-up of Seeded Bermudagrass Cultivars as Influenced by Spring Scalping

HortTechnology ◽

10.21273/horttech.21.2.230 ◽

2011 ◽

Vol 21 (2) ◽

pp. 230-235 ◽

Cited By ~ 9

Author(s):

Filippo Rimi ◽

Stefano Macolino ◽

Bernd Leinauer ◽

Umberto Ziliotto

Keyword(s):

Cynodon Dactylon ◽

Warm Season ◽

Early Spring ◽

Late Winter ◽

Winter Dormancy ◽

Green Cover ◽

Mediterranean Countries ◽

Northeastern Italy ◽

Soil Temperatures ◽

The University

Winter dormancy is the main impediment to a wide acceptance of warm-season turfgrasses in the Mediterranean countries of Europe due to a loss of color during the winter months. Scalping during late winter or early spring has been recommended anecdotally to enhance spring green-up of bermudagrass (Cynodon dactylon); however, information is lacking on the effectiveness of this practice. A study was conducted to investigate the effects of spring scalping on spring green-up of eight bermudagrass cultivars (Barbados, Contessa, La Paloma, Mohawk, NuMex Sahara, Princess-77, SR 9554, and Yukon) grown in a transition zone environment. The trial was carried out in Spring of 2009 and 2010 on plots established in July 2005 at the experimental farm of the University of Padova (northeastern Italy). Half of the plots for each cultivar were subjected to spring scalping, which was applied in both years on 13 Mar. with a rotary mower set at a height of 28 mm. Soil temperatures were recorded hourly during the research period at a depth of 2.5 cm. The percentage of green cover was estimated weekly from 0 to 98 days after spring scalping (DASS). Soil temperatures in scalped plots were greater than in unscalped plots. Among the cultivars tested, ‘Yukon’ showed earliest spring green-up, with no difference between the scalping treatments, reaching 80% green cover by the end of April. For all other cultivars, scalped plots reached 80% green cover 10 to 18 days earlier than unscalped plots. Results showed that scalping enhanced spring green-up, primarily for cultivars that recover slowly from winter dormancy.

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