Brief Summary of Minutes of Annual Meeting

1. Accomplishments

Accomplishments for this project included research, extension and teaching by 12 PIs at 9 states, coordinated for three objectives.

Objective 1: To quantify biophysical effects of grassland-based management strategies and climate change on N-use efficiency by ruminant animals, N cycling in herbage and soils, aquatic N losses, and GHG and other pollutant emissions from grassland agroecosystems.

Sub-Objective: 1.1 Use of new and novel plant materials for improved N-functionality in pasture (OH, MA)

Trifolium stoloniferum plants had been established at field locations throughout Ohio, in sites representative of their natural habitat. Measurements were conducted annually to quantify persistence and performance of this germplasm. Stolon segments had been collected from 5 Ohio locations during spring 2017 & 2018 and propagated vegetatively in a greenhouse. These represented both large (Class A, >1000 plants) and medium (Class B, 100-1000 plants) populations. Vegetatively propagated plants were replanted back to their natural habitat in fall 2017 & 2018 and spring 2018 & 2019. Resultant populations were measured annually (in 2025) to determine their long-term persistence.

            The collecting permit allowed collection of a “rooted node”, which typically comprised of two to four meristematic nodes (with leaves) and the active stolon tip. Immediately after collection, stolons were wrapped in moistened paper towels to prevent dehydration and stored on ice in a cooler to prevent heating. Stolons were planted in media (Metro Mix) in a greenhouse within 6 hr of sampling. Soil from the respective sampling location was mixed with the media at approx. 1:20 (v/v) ratio to allow for any site-specific biota (rhizosphere fungi, bacteria, etc) to inhabit the roots of the establishing stolons/plants. All plants grown from collected stolon cuttings shall be re-planted to their original location in consultation with DNAP (ODNR) and the landowners. Replanting occurred in Fall 2018 & 2019 and spring 2018 & 2019. Locations comprised of a generally uniform area of about 100 sq m that was free of any natural T. stoloniferum plants. Transplants were planted at a 1m grid spacing and after planting, stolon number and length of each transplant was measured.

Plant populations were measured at 4 of the 12 planted sites in Spring 2026, according to ODNR Permit #RP2026-35. The total number of plants (crowns) was 4077 (up from 3628 in 2025). This was a 45% increase from the total known population of approximately 9000 plants at the natural sites in Ohio. Within the Morgans Camp site, one sub-site (#14) continued a strong population from prior years, but 2 sites had a decreased population due to silt deposition from flooding by the adjacent river, and an exceptionally dry summer in 2024. Within the Lake Katherine site, two sub-sites (Salt Creek and Pine Ridge) both showed an increase in the plant populations from prior years due to the spread of stolons beyond the original planted area. Within the Bosch Hollow site, one sub-site showed an increase in plant population from 2025 due to spread of stolons beyond the original planted area, but two sub-sites showed a loss of plants. At the Bosch Hollow site, one sub-site had high plant counts, with 2037 plants, making this among one of the most prolific sites in Ohio. Two additional sites at Bosch Hollow had similar plant numbers as 2025.

Managing upright crabgrass as a new summer forage. In the Northeast, low availability of perennial cool-season forages during June through August stresses farm budgets and can lead to overgrazing which harms the long-term productivity and health of agricultural lands. Summer forage shortfalls will likely worsen as the climate changes and becomes hotter and dryer. Forage crabgrass (Digitaria ciliaris and Digitaria sanguinalis) is a warm-season annual forage that is productive in the southern United States but unknown in the Northeast. However, the ecology of its weedy relatives and recent studies from the Midwest suggest that it could be a useful alternative summer forage in northeastern dairy and livestock farming.

To fully investigate the innovative use of crabgrass in the Northeast, three experiments were performed at the University of Massachusetts in 2022 and 2023:

1) Quick-N-Big crabgrass was planted at four times (mid-May, early June, mid-June, and late June) and three seeding rates (3.4, 6.7, and 10.1 kg ha^–1). Weekly sampling explored the relationship between growth stages and forage yield and quality.

2) Four improved crabgrass varieties were evaluated for yield and quality with four nitrogen fertilizer treatments (56 kg ha^–1 at planting, 112 kg ha^–1 at planting, 56 kg ha^–1 at planting and 56 kg ha^–1 after the first harvest, and no nitrogen control). The crabgrass was harvested twice each summer to evaluate performance in a multi-cut system.

3) Crabgrass, pearl millet, and sudangrass were grown and evaluated for their forage quality as hay and haylage.

The experimental results yielded the following management recommendations for forage crabgrass production in the Northeast:

• Both crabgrass species are viable summer annual forages in the Northeast US and could be used for grazing, baled hay, and wrapped haylage using widely available equipment.
• 3000 kg ha^–1 of dry matter can be grown in six to seven weeks with relative forage quality over 100 and more than 15 percent protein.
• Highest high-quality yields are achieved by planting in the first half of June.
• 56 kg N ha^–1 per forage harvest is sufficient for forage production.
• Sanguinalis has moderately better forage quality than D. ciliaris, but D. ciliaris has higher (although slower) regrowth potential.

Sub-Objective: 1.2 Quantification of N-cycling as affected by grazing and pasture type (MI)

Research in Michigan aimed to measure nitrogen cycling in biodiverse perennial forage mixtures. The specific objectives were 1) Evaluate how long-term mixtures of perennial legume and grass influence biological nitrogen fixation and soil N pools, and 2) assess differences in soil N fractions and health among long-term genotype monocultures within perennial forage species. In FY2025, laboratory analyses were completed on forage nutritive composition and tissue 15N for the natural abundance method. Statistical analyses are ongoing with an MS student targeted to finish in May 2026.

A related study aimed to measure the effect of intercropping alfalfa and corn silage on soil health. The specific objectives were to quantify crop yield and quality, nitrogen credits, and soil health when intercropping silage corn with alfalfa. In FY2025, the final corn harvest was recorded in October 2024 and an extra alfalfa harvest was recorded in May 2025. Soil samples were collected in spring 2025 and are pending commercial analyses for soil health attributes following the methodological recommendations of the Soil Health Institute for gravimetric soil moisture, aggregate stability, total C and N, carbon mineralization, and labile C. Forage quality laboratory analyses are complete. The MS student who conducted the research defaulted to a non-thesis MS in Aug. 2025, delaying project completion. A post-doc was hired in Dec. 2025 to complete the statistical analyses and write the papers.

Sub-Objective 1.3. Quantifying Ecosystem Services as measures of Sustainability in Soil Smart Grazing Systems

Research in Nebraska (Dr Andrea Basche and team) is evaluating yield outcomes and ecosystem services of perennial ground cover in corn-soybean rotations. The experimental design includes evaluation of two species of perennial grasses (bulbous bluegrass, Poa bulbosa, and Kentucky bluegrass, Poa pratensis).

These systems have the potential to provide multiple ecosystem services including improved soil and water conservation, and increased carbon sequestration. Despite these environmental benefits, there is very limited use of PGC systems, even more so than annual cover cropping, due to concerns about potential reductions in cash crop yield. Yield penalties primarily arise from competition for light, water, and nutrients between perennial ground covers and the cash crop. Some early experimenters of these cropping systems include farmers who are grazing the perennial cover crops in fall and spring.

Field experiments evaluating perennial ground cover (PGC) systems were initiated across multiple Midwest locations, including sites in eastern Nebraska and central Iowa, as part of a coordinated multi-state research effort initially funded in 2024 by the Department of Energy. The study is conducted in a split-plot experimental design with crop rotation (continuous corn, corn-soybean and soybean-corn) assigned as the main plot factor and perennial cover treatments as subplots. Perennial cover crop treatments established in September 2024 included Kentucky bluegrass (Poa pratensis, non-dormant species), Radix hybrid bulbosa (Poa bulbosa, summer dormant species) (Figure 2), and a no-grass control. In summer 2025, corn and soybean were planted at 30-inch row spacing into previously established perennial cover crops seeded the prior fall to simulate practical field implementation of the PGC system. During the first growing season of this experiment (2025), data collection focused on evaluating crop–cover crop interactions and their effect on cash crop yield. Measurements included spring perennial ground cover and weed biomass, PGC height, crop stand counts, crop growth parameters, and end-of-season grain yield (Table 1).

Grassland restoration for bison grazing in a space-limited environment

Additional research in Nebraska (Nic McMillan and Andrea Basche) is working in partnership with the Henry Doorly Omaha Zoo to build research projects of shared interest that are feasible within the space-constraints and animal intensity of their environments. In 2025, we established an experiment at the Zoo’s Wildlife Safari Park facility near Ashland, Nebraska. They have maintained a bison herd on an approximately 40-acre mixed vegetation (grass, trees) land area for several decades. Over time the pasture has been heavily degraded. After many conversations we created an experiment to evaluate re-vegetating a portion of the pasture with minimal disturbance to the pasture. The experimental design includes five treatments of perennial forages (intermediate wheatgrass, smooth brome, intermediate wheatgrass + smooth brome, intermediate wheatgrass + alfalfa, intermediate wheatgrass + smooth brome + alfalfa) within and outside of a fenced enclosure, contained with approximately 1-acre of the pasture. Treatments were planted in early September 2025, after mowing existing vegetation, in order not to apply herbicides or tillage that might affect the animals or further degrade the pasture.

Dakota Wagner, Supervisor of the Browse Program at the Zoo, began an MS program under the primary supervision of Nic McMillan, and through support of his boss, Dr. Cayla Iske, Lead Animal Nutritionist. while continuing his full time work. Beginning in fall 2025, he began evaluating treatment establishment, species composition, biomass productivity, and forage quality, which continues monthly in the 2026 spring, summer and fall periods. 

Sub-Objective: 1.4  N-leaching and N-dynamics to improve Soil Health (UT)

Research in Utah using cover crops to improve soil health and reduce nutrient leaching. Cover crops were interseeded into silage corn when the corn was at the V3-V5 stage.  Interseeding early in the season is needed due to the short growing-season, and the lack of rainfall and irrigation water later in the season.  Leachate samples were collected bi-weekly throughout the year, as possible (typically early spring through late fall). Soil samples were collected to a depth of 150 cm at the beginning and end of each growing season.  Leachate samples were analyzed for nitrate and dissolved phosphorus.  Soil samples were analyzed for nitrate, ammonium, and phosphorus.  Preliminary results showed that both nitrate and dissolved phosphorus leaching was reduced by more than 50% when cover crops were interseeded compared to no cover crop.  Few significant differences have been observed in the soil samples.

The preliminary results showed that cover crops not only help improve soil health but also reduced nitrogen and phosphorus leaching thereby helping maintain those nutrients for future crop growth.

Objective 2. Determine the role of plant secondary metabolites in ensuring improved pasture sustainability, enhancing animal health and performance, and decreasing the animal environmental footprint.

Researchers in two states (TN, KY) worked on projects determining the potential for secondary metabolites (from plants or bacteria) to improve forage and livestock production, and reduce greenhouse gas emissions from soil

Red clover can be incorporated into pastures to reduce occurrences of grass tetany, mitigate fescue toxicosis, and fill production gaps. Biochanin A (BCA), one of the isoflavones produced by red clover, improves animal performance through a reduction in hyper-ammonia producing bacteria in the rumen which makes forage N available for animal use. Recent work has shown that BCA reduces ammonia volatilization and nitrous oxide emissions from urine-amended soil. However, the mechanism by which BCA affects N gas emissions is not known. Soil in Kentucky was amended with urine containing one of three doses of BCA: 0, 250, or 500 μg. Soils were incubated for 13 days in 1 L jars, and greenhouse gas emissions were measured on Day 1-7, 9, 11, and 13 after urine amendment. Additional incubations were terminated on Day 1, 3, 5, and 13 for soil N work including soil nitrate, soil ammonium, and urease activity. Similar to prior work, we found that BCA reduces ammonia volatilization from urine applied soils; however, we found no significant BCA effect on nitrous oxide fluxes, soil ammonium or nitrate pools, or urease activity. Thus, we are unable to identify the mechanism driving the BCA-induced reduction in ammonia volatilization. Additional evaluation of possible driving mechanisms is needed.

Red clover (Trifolium pratense L.) is a widely grown perennial forage legume that supports sustainable livestock production through its high nutritive value and bioactive isoflavones. Future climate variability, particularly warming and increased rainfall, may influence forage accumulation and isoflavone concentrations. However, field evidence integrating the combined effects of these climate factors remains limited. To address this gap, we conducted a 2-year field experiment in central Kentucky manipulating temperature (+3˚C, day/night) and precipitation (+30% of the long-term mean) on red clover (cv. Kenland). Plants were harvested multiple times in a growing season to mimic hay production, and isoflavones were quantified. Warming reduced total isoflavone concentrations by 15% though responses varied by cutting and year, while precipitation alone did not affect total isoflavone concentrations. However, elevated temperature stimulated daidzein concentration in late summer, and the effects of added precipitation on daidzein differed among cuttings. Warming decreased red clover aboveground biomass by 14% across years, whereas added precipitation tended to increase biomass by a similar magnitude but did not significantly offset heat-related losses. These results suggest that future climatic conditions may reduce red clover productivity and total isoflavone concentrations. Additional rainfall showed limited evidence of mitigating warming-driven reductions in biomass and isoflavone concentrations, and warming may induce compound-specific changes in isoflavones (e.g., daidzein). These findings have mixed implications for forage–livestock systems. Decreased isoflavone concentrations (e.g., formononetin) may reduce reproductive risks in livestock, whereas decreases in other isoflavones could diminish benefits related to animal performance and environmental sustainability.

In an additional project in Tennessee, researchers evaluated the potential use of plant growth-promoting bacteria (PGPB) as an alternative strategy to reduce nitrogen (N) fertilization requirements in forage systems. Research was conducted in tall fescue and crabgrass-based forage systems in Tennessee to assess the effects of bacterial inoculants on forage productivity, nutritive value, and livestock performance. Small-plot trials in Crossville evaluated Paenibacillus sonchi, Bacillus subtilis, and Methylobacterium symbioticum under different nitrogen sources and rates. Grazing trials in Spring Hill evaluated Azospirillum brasilense in established crabgrass overseeded with winter annual forages. Results indicated that bacterial applications did not increase forage production or quality compared with non-inoculated treatments; however, A. brasilense maintained forage and animal performance while allowing a reduction of 17 kg N ha⁻¹, demonstrating potential as a tool for improving nitrogen use efficiency.

Field experiments were conducted in Crossville and Spring Hill, Tennessee. In Crossville, tall fescue plots were treated with P. sonchi (bv. DH44), B. subtilis (bv. DH267), and M. symbioticum (bv. UrtrishaN) combined with varying nitrogen rates supplied as ammonium sulfate or urea. Plots were harvested throughout the growing season at the boot stage to evaluate forage mass, morphological composition, and nutritive value. In Spring Hill, established crabgrass paddocks received A. brasilense with or without nitrogen fertilization. The bacterium was applied through foliar spraying of established crabgrass and seed coating of overseeded wheat and annual ryegrass. Weaned steers grazed the paddocks during fall 2024 and 2025, with biweekly forage sampling and evaluation of forage characteristics, animal performance, and economic returns.

1. Grants, Contracts & Other Resources Obtained

Daugherty Water for Food Institute Student Fellowship. 2026-2028. $57,000

USDA-NIFA. Sungrant Program. Evaluating the potential of perennial cover crops to improve carbon intensity of corn production. 2026. $60,000

Henry Doorly Omaha Zoo partnership, funding supporting salary for Dakota Wagner, MS graduate student in Agronomy at UNL.

McCulley, R.L. (PI). “Plant natural products and symbiotic diversity improve pasture sustainability.” USDA-FAPRU-NA Cooperative Agreement. 2024 – 2028. $282,350