Evaluating forage-based strategies to improve sustainability and resilience of perennial forage ecosystems

Commodities

Practices

In the Southeast region, livestock operations are based on forages as the primary feed source. Perennial grasses require inorganic nitrogen fertilizer input to support forage production, quality, and animal performance. They go dormant for a portion of the year which requires planning to conserve feed or have additional grazing areas. In livestock operations based on warm-season perennial grasses, such as bahiagrass (Paspalum notatum Flügge) and bermudagrass (Cynodon dactylon L.), a common practice is to overseed the stands with cool-season annuals to extend grazing. Historically, producers have relied on monoculture or binary combinations of grasses when implementing this practice. With the increasing price of fertilizers, concerns about negative environmental impacts, and expansion of cost-share programs, producers started incorporating forage legumes, mostly clovers (Trifolium spp.), and diversifying their forage ecosystems. In recent years, there has been a focus on exploring diverse mixtures targeting additional benefits and ecosystem services that those combinations can provide and supporting climate-smart practices to enhance carbon sequestration and nutrient cycling and reduce soil compaction.

This project will determine forage agronomic, soil health, and ecosystem services responses from warm-season perennial stands overseeded with three cool-season mixtures containing diverse plant functional groups. Treatments will consist of 1) oat (O, Avena sativa) + wheat (W, Triticum aestivum) + annual ryegrass (A, Lolium multiflorum); 2) O + W + A + crimson clover (C, T. incarnatum) + red clover (R, T. pratense) + hairy vetch (H, Vicia villosa) + radish (S, Raphanus sativus); 3) triticale (T, x Triticosecale Wittmack) + A + C + R + H + S.  A 2-year study will be conducted with three replicates under a randomized complete block design. Herbage mass, botanical composition, and forage nutritive value will be determined. Residual biomass and existent litter will be sampled. At the research and on-farm sites, soil samples will be collected before and after treatment imposition to determine soil bulk density, nutrient accumulation, and health parameter changes at 0-5, 5-10 and 10-20 cm soil depths. Pollinator and dung beetle characterization will be conducted, and additional soil health samples will be collected at the research stations. Research findings will be disseminated through Extension and educational in-person efforts (e.g., webinars, field days, workshops) and written resources (e.g., fact sheets). A producer panel will be held at the Sunbelt Expo in Moultrie, GA with our collaborators to discuss the major challenges and experiences and to promote proper establishment and management practices of overseeding stands while discussing soil health, nutrient cycling, and sustainability with stakeholders. COVID-19 guidelines will be observed, and adjustments made, if needed. Producers' experiences and perceptions will be captured and included in outreach publications to be developed. Research and Extension-related data will be presented at conferences and local, statewide, and regional events. Findings will be published in refereed journals. This project builds upon previous ongoing efforts under Drs. Silva’s and Mullenix’s research programs will continue to foster collaborations between these research and Extension groups and ongoing efforts to generate research-based information and recommendations to disseminate to producers in the region.

The main objective of this proposal is to determine forage agronomic, nutrient cycling, soil fertility and health and ecosystem services responses of year-round forage-livestock systems managed under rotational stocking. These perennial warm-season grass systems will be overseeded with contrasting forage mixtures utilizing different plant functional groups aiming to increase forage production and growth distribution, and enhance nutrient cycling and accumulation in the soil, while supporting animal performance, feasibility and resilience of operations. In addition, the goal is to improve ecosystem services delivery by implementing diverse cool-season forage mixtures into year-round forage ecosystems. The goals will be achieved by developing research studies to quantify response variables described below and findings will be used to support the development of written technical educational resources and deliver outreach activities (i.e., field days, workshops) to disseminate research-based knowledge and recommendations to support improved sustainable production and resilience of ecosystems.

The specific objectives are:

• Determine forage mass, residual biomass, and litter composition and decomposition of contrasting cool-season annual forage mixtures managed under grazing in year-round forage-livestock systems. The forage systems used in this project are described on Table 1 and comprise of grass only or grass-legume-brassica mixtures. The additive effects of the inclusion of legumes and brassica will be able will be determined by comparing treatments 1 and 2. The third forage treatment contains triticale (x Triticosecale Wittmack) which is cool-season grass that is growing in interest and use in the region associated with longer forage distribution than cereal ryegrass (Secale cereale ) and oat (Avena sativa L.), and with comparable seed costs to them. The approach for the treatments used in this project is as forage systems which the goal is to complement growth and forage production while support organic N fixation, nutrient cycling and ecosystem services provided by them.

• Determine short-term effect of forage mixtures and fertilization practices on soil health and nutrient accumulation and dynamics under contrasting forage mixtures. Additionally, determine pollinator and dung beetle characterization as affected by the forage treatments. The forage treatments used vary on plant functional groups and quantifying their impact on nutrient input, soil nutrient accumulation and health indicators and ecosystem services help to guide recommendations and support better understanding of organic matter incorporation into year-round forage systems overtime. In addition, characterizing dung beetle species will allow for better understanding of their impact in these ecosystems in the region. Pollinators have a crucial role in forage and general crop (e.g., cash crop) areas, and their characterization in this project allows to better understand diversity of species, even though the major focus will be placed in bees for this project’s purpose.

            Outcomes of objectives #1 and 2: Results will be presented in scientific and Extension events locally, regionally, and nationally. In addition, results will be compiled into technical publication after the refereed journal publication is finalized. Multiple presentations are expected from graduate students and Co-PIs.

• Development of regional written and online educational resources and outreach efforts to disseminate research-based findings and recommendations, while incentivizing adoption of practices for adequate establishment and management practices in operations. Producer collaborators will share their experiences and challenges for implementation of practices in the region. This objective focuses on the development of research-based educational resources to improve forage and livestock production, resilience, feasibility, and sustainability of year-round operations. This content will provide participants with educational tools to help them manage risks and improve the sustainability, feasibility, and resilience of their operations.

            Outcomes: Outcomes will include written educational resources (i.e., handouts), recorded content (i.e., webinars), and the development of an economic analysis tool to be stored on regional online website. Additionally, producer cooperators will provide feedback and will participate from the beginning of the project in annual planning meeting, and in field days to be held at their farms and at research stations. They will also attend a roundtable at the 2027 Sunbelt Ag Expo to discuss and share their experiences and challenges in adopting practices. This team is involved with the planning of the Beef and Forages Barn at the Sunbelt Ag Expo in Moultrie, GA, and will plan to deliver educational content there through talks and distributing printed materials on years 2 and 3. Dr. Silva will be the moderator of the roundtable in 2027 with support of other Co-PIs.

            Evaluation plan: For this objective, evaluation tools will include compiling attendance and participation at in-person and online events and collecting web metrics (i.e., views and downloads) of resources (i.e., recordings, tools) stored online. In addition, pre- and post-knowledge surveys will be applied to online and in-person events and results and feedback compiled for use and improvement of future Extension and educational events under this project. Feedback provided by producer collaborators will also be compiled to address their experiences and major challenges associated with managing their year-round systems under this project.