Interseeding alfalfa (Medicago sativa L.) into bermudagrass [Cynodon dactylon (L.) Pers.] can be an effective way to improve forage quality and reduce the need for additional supplementation when fed to livestock. The objective of this research was to compare the nutritive value and forage mass of bermudagrass with and without interseeded alfalfa when harvested as baleage. On 19 Feb. 2016, 0.2‐ha plots were assigned in a randomized complete block design to either ‘Tifton 85’ (T85) or T85 interseeded with ‘Bulldog 805’ alfalfa (T85+Alf) in an established field of Tifton 85 bermudagrass at the University of Georgia Tifton Campus, Tifton, GA. The T85 received 84 kg N ha⁻¹ four times throughout the growing season. Plots were harvested at early bloom stage every 28–35 d throughout the growing season, baled at 40–60% moisture, and individually wrapped. At each harvest, plots were evaluated for botanical composition and forage mass, and bales were sampled prior to wrapping for nutritive value analysis. The T85+Alf plots produced additional harvests each season, leading to greater herbage accumulation than T85 plots (P < .01). The T85+Alf treatment had greater crude protein and total digestible nutrients than T85 in each of the 3 yr, suggesting this mixture will need no or less supplementation to meet the nutritional requirements of a lactating beef cow. Therefore, interseeding alfalfa into a bermudagrass system improves forage mass and nutritive value.

Core Ideas: Temperature significantly affects the time and rate of clover (Trifolium spp.) germination. Germination and vigor were evaluated from −1.0 to 48.0°C at approximately 1.0°C increments. Tested cultivars maintained 80% + germination from 4.9 to 28.2°C, on average. Temperature range for germination was much wider than reported in previous literature. Data will be useful in updating planting recommendations for producers in the US Southeast. There are many reports of failed clover (Trifolium spp.) establishments each year. Temperature is one of the primary factors affecting germination and significantly affects the time and rate of clover seed germination. The objectives were to determine (i) the temperature and time required to reach maximum germination and (ii) range in which germination will occur for six coated clover cultivars adapted to the US Southeast. Seed germination and vigor were evaluated in Petri‐dishes incubated over thermal gradients ranging from −1.0 to 48.0°C at approximately 1.0°C increments where germination was counted every 24 h for 7 consecutive days. Base temperatures were calculated for each cultivar. Three parameter logistic growth models were used to find the minimum and maximum temperatures at which these cultivars could maintain 80% germination. Lorentzian distribution models were used to establish the temperature and time to maximum germination. These cultivars maintained at least 80% germination from 4.9 to 28.2°C on average, although some germination was observed outside these extremes. The range at which these clovers could germinate was much wider than previously reported. Excluding ‘Barduro’, maximum germination occurred at 34.2 to 52.8 h after planting at optimum temperatures (10.9–17.2°C). Barduro germinated so rapidly in the warmer temperature range that the full data set could not be used, as it did not conform to the same regression. Future trials will begin measuring germination at 12 h to better capture early trends in germination. These data will be useful in updating planting recommendations for producers in the US Southeast.

Alfalfa use (Medicago sativa L.; “lucerne”) in warm, humid regions of the world represents a potential area of expansion for the alfalfa industry. The objective of this review paper is to demonstrate how alfalfa forage breeding and systems research efforts have identified opportunities for increasing alfalfa contributions in these regions, along with potential pathways for seed industry and farming operations to increase adoption. Our review draws primarily on reports from the Southeast United States and Argentina. Significant technological advancements in plant screening and selection have identified alfalfa plant populations that are more adapted to the growing conditions experienced in these regions, which are often characterized by mild temperature, long growing seasons, and multiple other abiotic and biotic stressors. Management systems research conducted in the United States and Argentina has demonstrated the use of alfalfa for conserved forage, grazing, or dual‐purpose use in monoculture or mixtures with warm‐season grasses such as bermudagrass (Cynodon spp.). These trials report increased forage production, nutritive value, and ecosystem services of alfalfa–grass mixtures when compared with traditionally N‐fertilized warm‐season grass‐based systems. Grazing‐based alfalfa systems in Argentina have demonstrated methods for utilizing alfalfa as part of beef, dairy, and finishing systems. Some approaches for expanding alfalfa production in the region include targeted marketing efforts for adapted varieties and demonstrating alfalfa applications within existing farming frameworks. This includes educational programming efforts and on‐farm demonstrations to promote alfalfa use as a component of the livestock diets, integration into grass‐based systems, crop rotations, and wildlife use. Continued emphasis on a systems approach to alfalfa inclusion represents an opportunity for improved forage and livestock production in warm, humid regions of the world.

Potassium fertilization and harvest timing both influence the stand life and performance of alfalfa (Medicago sativa L.), but many producers do not apply sufficient K fertilizer as recommended by soil test recommendations. The objective of this trial was to determine the impact of reduced rates of K fertilization on cultivar Bulldog 805 alfalfa managed under different harvest regimes on forage yield, stand persistence, and nutritive value when grown in the southern Coastal Plains. Plots were harvested at bud, 10, 30, and 50% bloom growth stages. Potassium was applied three times across the season at total rates of 0, 67, 101, 134, and168 kg K₂O ha⁻¹. Aboveground and belowground plant and soil responses were evaluated. Evaluated levels of K were not sufficient to elicit a positive response in aboveground variables, as all treatments exhibited K deficiency as confirmed by tissue analysis at the end of the study. Harvest timing affected many of the aboveground yield components, however no clear trends existed. As expected, material harvested at later growth stages tended to have higher fiber and lower digestibility than alfalfa harvested at less mature stages. Reduced rates of K fertilization helped maintain soil K levels above the final level in the untreated control. Harvesting alfalfa at later (50% bloom) growth stages decreased starch and nonstructural carbohydrate (NSC) content in the roots. To optimize both alfalfa yield and nutritive value, current University recommendations for alfalfa harvest timing and K fertilization should be maintained in the southern Coastal Plains.

Johnsongrass [Sorghum halepense (L.) Pers.] is a non-native, invasive species that causes substantial losses in row crop and hay fields, which could be minimized by using Johnsongrass as a conserved forage. Two experiments were conducted to evaluate yield and quality of Johnsongrass ensiled at four maturities: harvested every 3 weeks (3WK), boot stage (BOOT), flower stage (FLOWER), and dough (DOUGH) stages. In experiment 1, yield, botanical composition, nutritive value, and fermentation characteristics of Johnsongrass were measured. In experiment 2, Johnsongrass silage was incubated for 48 hours for assessment of gas production, pH, in vitro dry matter digestibility (IVDMD) and volatile fatty acids (VFAs). The experimental area consisted of 16 plots (2.74 m x 4.57 m) divided into four blocks, and treatment was randomly assigned to plot within block. Each year, silage was prepared for each plot from the two cutting closest to July 1. After 10 weeks, the silos were opened, and silage samples were frozen for further analysis. Data from both experiments were tested for the effects of maturity stage and harvest timing (first and second harvest). The results from experiment 1 showed an increase (P < 0.0001) in DM yield from 3WK stage to DOUGH. Johnsongrass, as a proportion of the total botanical composition, declined at the end of the growing season for 3WK, but increased in FLOWER (P = 0.0010). In the first harvest, 3WK and BOOT stage silages had greatest concentrations of CP and TDN and lowest of fiber (NDF and ADF; P < 0.0001). In the second harvest, differences in nutrient content were significant only for 3WK silages, which showed the best nutritive value (P < 0.0001). In experiment 2, IVDMD of silage followed the same trends described for nutritive value from experiment 1. Overall, these results demonstrate that Johnsongrass can be successfully ensiled, but to optimize forage nutritive value and quantity, Johnsongrass should be ensiled before it reaches the flower stage.

Background: Bermudagrass (Cynodon spp.) is one of the most common perennial warm‐season forages grown in the Southeastern United States. The incorporation of alfalfa (Medicago sativa) into bermudagrass pastures could serve as an alternative source of nitrogen (N) while also improving the nutritive value of the forage base.Methods: A 2‐year grazing evaluation arranged in a randomized complete block design was conducted from May to September 2018 (Year 1) and May–August 2019 (Year 2) in Tifton, GA, USA. The objective was to compare the production of alfalfa–bermudagrass mixed pastures (BGA) with bermudagrass monoculture pastures with (BGN) or without (BG) the application of synthetic nitrogen on forage production and stocker cattle performance.Results: Differences were observed for average daily gain (p = 0.10), gain per hectare (p = 0.02) and stocking rate (p = 0.01), in that BGA was greatest compared to BGN and BG, which did not differ from each other. Furthermore, BGA had increased forage crude protein (p = 0.01) and total digestible nutrients (p = 0.01) compared to BGN and BG. Finally, BGA provided the greatest economic return per hectare compared to BG or BGN.Conclusions: These data illustrate improved animal performance and forage nutritive value using alfalfa–bermudagrass systems and offer a viable option for producers seeking alternatives to synthetic N sources for bermudagrass pastures in the Southeastern United States.