Dillon P. Golding1,2, Francis A. Reith1,3, and Jonathan O. C. Kubesch1,3
- Virginia Tech School of Plant and Environmental Sciences, Blacksburg, VA
- Hoot Owl Hollow Farm, Woodlawn, VA
- Country Home Farms, Pembroke, VA
Editor’s Note: The imperial data in this article applies to Virginia, but similar results can be expected in Kentucky.
Native grasslands in the Midsouth previously existed in a mosaic of plant communities across moisture and fertility regimes (Noss, 2013; Campbell, 2012). These grasslands persisted through a variety of edaphic, moisture, fire, herbivory, and human dynamics. The arrival of Europeans brought land use change, the removal of elk (Cervus canadensis) and bison (Bison bison) herds, and the arrival of cattle. These shifts in the fundamental drivers of these grassland ecosystems led to shifts in many native grasslands. While many native plants disappeared from the landscape, some persisted in modern plant communities.
Some of the native species that make up remaining grasslands persist despite the deleterious effects of early European settlement. These species survive because of their anatomy, management, or ecological strategy. For instance, species with lower-positioned meristems can regrow more effectively following overgrazing than species with higher-positioned meristems. Given that most pastures are managed at shorter heights than most traditional grasslands, these low-growing native grasses can persist within modern grazed ecosystems.
Similarly, native grasslands only used seasonally are more likely to persist following a grazing event than grasslands subject to year-round grazing (Figure 1). These grasses display either competitor or ruderal ecological strategies where they can handle the disturbance inherent to cattle grazing as well as the limited resources in herbaceous plant communities. Some especially persistent competitor or ruderal species might even disperse to other pastures from native grasslands.
Two of these species include splitbeard bluestem (Andropogon ternarius) and little bluestem (Schizachyrium scoparium). In Virginia, both species have a coefficient of conservation of 5, which suggests moderate conservative ecological behavior (DeBerry et al., 2020). These species are thus more so competitor species than ruderal ones. These species are seen on drier soils with acidic to average soil fertility throughout the Upper South (Campbell, 2012). Their meristems are closer to the soil level than species like big bluestem (Andropogon gerardii) or Indiangrass (Sorghastrum nutans), which allows them to survive intense grazing events. Cattle are known to graze these grasses (Leithead et al., 1971).
These species have been seen moving around cattle farms by means of hay transfer. Hay transfer involves the strategic spreading of nutrient-rich hay or straw on bare or disturbed soil surfaces within a restoration site. This practice serves multiple ecological purposes, including erosion control, moisture retention, and the provision of a conducive environment for the establishment of native vegetation. The layer of hay acts as a protective blanket, shielding the soil from erosive forces such as wind and water, while also offering a conducive microhabitat for seeds to germinate and young plants to take root. Additionally, hay transfer aids in the suppression of invasive species and facilitates the natural regeneration of indigenous plants, fostering a healthier and more biodiverse ecosystem.
In the realm of ecological restoration, the process of hay transfer plays a crucial role in nurturing and revitalizing degraded landscapes (Dubecq et al., 2022). As an integral part of ecological restoration strategies, hay transfer embodies a holistic approach to landscape rehabilitation, emphasizing the importance of sustainable practices for the long-term health and resilience of ecosystems.
Hay is primarily fed during the winter months in the Midsouth (Figure 2), and the number of hay-feeding days can range from 0 to 120 days (Gerrish, 2018). Cooperative Extension research has sought to reduce the number of hay-feeding days to 60 days on most farms (Graze 300), and this window generally falls from January to March of each year (Figures 2 and 3).
Increasing fertilizer prices and new perspectives regarding hay have led agronomists and economists to suggest hay feeding on low-fertility soils. Native grasses have an advantage on these low-fertility areas (University of Kentucky, 2021).
This winter hay-feeding window is optimal for hay transfer. Potential seed dormancy can be accomplished through cold-moist stratification. Even species that do not require stratification can benefit from this form of seed conditioning (Bellangue, 2023). Winter hay-feeding does happen to eliminate the existing sod around the area hay is fed. Most sods are currently nonnative tall fescue (Schedonorus arundinaceus), and previous research suggests that the sod must be destroyed to plant native species (Figure 3) (Bellangue, 2023).
A final benefit of approaching hay-feeding areas is that these areas are often deferred from grazing for a substantial period in the spring and summer (University of Kentucky, 2021; Teutsch & Mercier, 2020). A 60-70 day rest from grazing is a minimum requirement when trying to get most grassland species established.
Given this potential strategy of establishing native bluestems in winter hay-feeding areas, this present microcosm, or simulation, sought to determine whether splitbeard or little bluestems will germinate under hay-feeding conditions. The hypothesis for this simulation was that little bluestem would produce more seedlings per inflorescence sown than splitbeard bluestem.
Materials and Methods
The present experiment sourced wild-collected, mature seedheads of both bluestems from a working cow-calf grazing system in Carroll County, Virginia. This site has been the primary case study driving the study of working reference grasslands (Kubesch et al., 2023; Kubesch, 2023). Additionally, this seedy hay harvest reflects the reality that many cattle farms cut their tall fescue late in the year, in order to maximize yields at the cost of nutritive value. This often aligns with seed maturity in the bluestems. In real fields this timing seems to be dispersing the bluestems from harvested fields into hay-feeding areas.
The microcosm was assembled at Virginia Tech’s Grassland Ecology Lab, 350 Smyth Hall, Blacksburg, Virginia. A plastic planting tray lined with paper towel was filled with a moisture-control potting mix to a depth of 2” (PROMIX Premium Organic Vegetable & Herb Mix; Premier Horticulture Inc., Quakertown, PA). Seedheads were counted for a sample of splitbeard and of little bluestem and laid on adjacent halves of the tray. Seedheads were covered with ¼” of loose potting mix. The tray was watered through flooding a light bench to moisten the media. This seed placement mimics the stems of hay that might be wasted during the winter hay feeding season.
Subsequently, the moistened tray went into a refrigerator at 41°F for 18 days, with occasional misting from a spray bottle to maintain media moisture during this period. This stratification period mimics the seasonal weather of the Midsouth (46 °F high, 29 °F low in February). After 18 days under cold-moist stratification, the tray was moved back to the light bench. The tray was once more bottom-watered, and the light bench was maintained on a 24 hour light schedule at 60 °F during the night, and 75 °F during the day.
Emergence was measured at 3 weeks following this move to the light bench. This period was chosen because standard germination trials for native warm-season grasses have historically been run for 21 days (Ball et al., 2018). Emergence was measured again at 7 wk to account for the extended emergence period seen in native warm-season grasses (Keyser et al., 2020). Seedlings were counted regularly for both species and scaled to an emergence rate to account for slight differences in hay transfer rates.
Emergence rate = 100 × (Seedlings emerged / Seeds planted)
Results and Discussion
Splitbeard bluestem had emerged by the third week of the experiment and seedling counts increased at week 7 (Table 1). In contrast, little bluestem had not yet emerged by the seventh week of the experiment (Table 1). This trial was not replicated, and so comparisons between these species were limited.
| Species | 3 week emergence rate (%) | 7 week emergence rate (%) |
| Splitbeard bluestem | 7% | 20% |
| Little bluestem | 0% | 0% |
Establishment failure in grasslands can be documented at three phases soon after planting. Seed might fail to germinate, germinate, but fail to break through the soil, or emerge but fail to survive (Ball et al., 2018). In the context of hay transfer, the failure to produce viable seed is a concern, which is why results were scaled to the basis of seeds planted. Seeding rates can also be converted to a weight basis from seed weights.
The failure of little bluestem to germinate could have resulted from a suite of related factors. Seed was stored at room temperature and a low humidity was highly optimal according to the standards of Ball et al. (2015), so improper storage is unlikely to be the cause. Temperature is a key factor in the germination and growth of plants. However, nighttime temperatures of 60° F should mimic normal, early-summer growing conditions and allow germination. The microcosm placed seed at a ¼” depth which may have been too deep for seedlings to emerge. Ultimately, it may just be that splitbeard bluestem establishes more quickly than little bluestem under these conditions. Seed dormancy might also explain this difference in emergence rate.
Dormant seed will not germinate soon after an initial planting, which is why this microcosm simulated winter hay-feeding, so these counts may not reflect the true field emergence of these species. Splitbeard bluestem plug production has historically required stratification (Vandevender, 2008). The cold-moist stratification possible with winter hay-feeding seen here can serve as an alternative to costly seed conditioning practices. Seeds may struggle to germinate in certain hay-feeding situations, especially where pugging–or soil damage by hoof action–has destroyed a majority of a pasture. Pugging damage in hay feeding areas is generally avoided through rotational stocking or mitigated through tillage.
If a seedling emerges from the soil, weed competition and drought are the primary antagonists other than premature grazing. Grazing when plants are too young can result in plants either being ripped up or trampled. Seed that germinates too quickly is liable to get damaged if livestock are not moved quickly enough. Field observations suggest that little bluestem fills in several years after hay feeding, but is not as dominant in undisturbed areas as it is in the more heavily used areas (Golding, unpublished data). Germination rates are expected to be lower because the conditions are not superb, but native grass establishment has historically been an ancillary benefit rather than a primary one in these hay-feeding areas.
Current recommendations in hay-feeding contexts suggest that farmers need to use higher seeding rates in reclaimed hay-feeding areas than in normal planting contexts (Teutsch & Mercier, 2020). This means that Kentucky farmers might be planting 9 lb acre-1 (or 2,340,000 seedlings acre-1) of pure live seed for little bluestem (University of Kentucky, 2020; University of Tennessee, 2008; USDA Grass, 1948). Pure live seeding rates account for the germination of seeds accounting for dormancy and debris in samples. Emerged seedling counts from an applied hay rate can be treated as a form of pure live seed in this situation. The data generated from this exercise suggest that a hay transfer rate of ~290 lb acre-1 would produce 188,182 seedlings acre-1 for splitbeard bluestem by week 7. Concurrently, the data generated from this exercise suggest that a hay transfer rate of ~260 lb acre-1 would not produce any seedlings acre-1 for little bluestem by 7 wk. These hay rates are especially low relative to the 892-2,680 lb acre-1 rates used in hay transfer elsewhere as well as the relative hay waste seen on working farms (Moullard et al., 2014).
Another way to estimate an optimal seeding rate might be to back calculate a rate with a target seed density in mind. For example, the Ohio State University Agronomy Guide (2017) targets ~50 seedlings per square foot for most native grasses. At this target, ~3400 lb acre-1 splitbeard bluestem hay would be needed. This calculation is important because this amount would approximate the standing forage seen in splitbeard bluestem stands in the Midsouth. This steep requirement for seeding a new stand may partly explain why splitbeard bluestem can maintain solid stands where seed production occurs frequently.
Reclaiming hay-feeding areas can be accomplished through a variety of strategies. Farmers might simply burndown emerging weeds with glyphosate or smooth the hay-feeding area prior to seeding. This spray might favor native grass seedlings so long as the spray is timed prior to seedling emergence. This simulation offered a three-week window from planting to emergence given that seed required a three-week, cold-moist stratification period. This period could be used for herbicide control.
The simulation placed seed at ¼” depth under loose media, as might happen when hoof traffic or a drag harrow lightly covers loose hay. The intensity of smoothing or tillage operations depends on the damage to a field (La Grange, 2009). In a dynamic field context this tillage could result in variable seeding depth, and require higher hay rates to account for the buried seeds.
The hay transfer approach might also allow local ecotypes of native bluestems to be spread from farm to farm without the challenging economic and regulatory burden imposed on traditional seed sales. A farmer with hay making equipment could harvest, bale, and sell this seed hay at a premium to interested native plant enthusiasts.
Conclusions and Future Directions
The present microcosm sought to determine whether splitbeard or little bluestems will germinate in a hay-feeding context. The hypothesis for this simulation was that little bluestem would produce more seedlings per inflorescence sown than splitbeard bluestem. This project found that splitbeard bluestem appears to respond quickly after a cold, moist stratification event, whereas little bluestem seems less responsive.
This simulation is the first to generate emergence data for splitbeard bluestem in accessible literature. Despite the low hay rates used, splitbeard bluestem produced sizable seedling populations within 21 days. A field experiment with a greater level of verisimilitude could test the rate of hay as well as the reclamation strategy optimal for establishing these native bluestems in winter hay-feeding areas. Given these possibilities, hay transfer of native bluestems into winter hay-feeding areas might be a low-input, local approach to maintaining native plants in the wider landscape.
References
References for this article are hyperlinked throughout for easy access. If any links fail to open, please contact the corresponding author: Jonathan Kubesch, M.S. (jakubesch@gmail.com).
United States Department of Agriculture 1948 (Grass) and 1961 (Seeds) Yearbooks of Agriculture were examined in their original hard copy formats, though an internet archive is available.
A hard copy of Southern Forages (Ball et al., 2015) was utilized.
Acknowledgements
This simulation was made possible with the support of the proprietors of the unnamed Carroll County farm as well as Country Home Farms. Yearbooks were sourced from Roy Blaser’s (1912-2008) collection. Golding thanks John James and the employees at the Virginia Tech Urban Horticulture Center for allowing experiment material to be stored there.
Kubesch expresses his gratitude to Sarah Grace and Joseph Cole Kubesch for their encouragement and support.
Dillon P. Golding is a master’s student at Virginia Tech studying native grassland persistence and expansion in southwestern Virginia. He holds a B.S. in Animal Science from Virginia Tech and currently works at the Virginia Tech Urban Horticulture Center. Dillon has interests in pragmatic and sustainable agriculture, working native grasslands, and niche cattle breeds. He and his family operate a cow/calf farm in southwest Virginia.
Francis A. Reith is a master’s student at Virginia Tech studying crop improvement and genetics in wheat and barley. He holds a B.S. in Crop and Soil Science from Virginia Tech and is currently studying under Dr. Nicholas Santantonio. Francis holds interest in improving cropping systems in the Mid Atlantic. He and his family are cattle farmers in the Catskill Mountains of New York.
Jonathan O.C. Kubesch, PhD, will be Assistant Professor – Forages in the Animal Science Department in the University of Arkansas System Division of Agriculture at the Cooperative Extension Service in Little Rock starting April 1, 2023. Kubesch is a PhD crop, soil, and environmental sciences graduate of Virginia Tech. He previously pursued a master’s degree in crop science at the University of Tennessee. He studied ecology—as well as agronomy—at The Ohio State University. He works with forages, grasslands, and prairies with a particular passion for native clovers. Jonathan, his wife, Sarah Grace, and son, Joseph, have been ranching turkeys and ducks in the mountains of western Virginia.