RAPHINE, VA – Nearly 200 people attended the 2015 field day at Virginia Tech’s Shenandoah Valley Agriculture Research and Extension Center (AREC) at McCormick Farm recently. During the afternoon event, which culminated with dinner, researchers from throughout Virginia Tech and Virginia Extension’s broad team of scientists and researchers spoke about progress in their fields of study.
It’s fitting that Virginia Tech has been performing agriculture research here for 60 years, as this is the home farm of Cyrus McCormick, famous for building the first practical grain reaper. The farm remained in the McCormick family’s hands from the time of the famous forbearer (he was born on the farm in 1809) until 1954, when the family donated it to Virginia Tech.
One topic addressed at the meeting was the proper rate of phosphorus supplementation for beef cattle. One of the primary points made was that the best way to determine how much phosphorus to add to free-choice minerals is to test your forage, both fresh and stored forage. Farms that feed forages with higher levels of phosphorus won’t need as much supplemental mineral phosphorus.
Forages were discussed throughout many of the day’s presentations. In one case, visitors saw test plantings of a variety of summer annual and a few perennial warm-season forages. Both Augusta County Animal Science Extension Agent Matt Booher and David Hunsberger of King’s AgriSeeds discussed the varieties. (King’s donated the seed for the plots.)
There are a variety of summer annual forage options available, from teff, which is best suited for mechanical harvesting, to sudangrass, which is well suited to grazing. What’s best for you depends on your farm’s needs. Using fertility (nitrogen) is important in these crops. What’s more, when cutting sudangrass, use sharp equipment, advised Hunsberger. When harvested with sharp cutters, the plants will heal and regrow better
The research center is also the site of a project, still in its early stages, which will test how service lespedeza can mitigate fescue toxicosis. It’s thought that toxicosis can be reduced when grazing animals consume legumes with chemicals known as condensed tannins, which may detoxify fescue toxins. Service lespedeza has tannins and is adapted to this region. Next year on the research farm, steers will be grazed on a variety of pastures to test whether including service lespedeza in toxic fescue has an effect on animal performance.
Another topic of discussion was research efforts into selecting cattle that have resistance to fescue toxicosis. There are genetic markers linked to toxicosis resistance, but at present, there is no simple commercial test to determine if cattle have those genetic markers. Such a test may not be far off in the future, however.
Virginia Tech’s Dr. Ben Tracy, along with a graduate student, has been using the research station to study how different grazing strategies impact forage biomass. Specifically, Tracy is looking at continuous stocking, rotational stocking, and high-density rotational stocking (mob grazing). He presented some preliminary findings.
Forage mass was collected monthly in the various systems. The paddocks that were used for mob grazing had significantly greater forage mass than in the paddocks in the other systems. The paddocks used in the high-density stocking system also showed greater resilience to drought than the less intensely managed systems. The paddocks with the greater biomass also seem to store larger amounts of carbon in the soil.
The first paddocks subjected to mob grazing in the spring did show slower regrowth time than those used in other systems, leading Tracy to conclude that for such systems it’s best to delay grazing until grasses are six to eight inches tall.
Another project underway at the research station involves the establishment of silvopature. Silvopasture is used often in the South among pine plantations, and in the Pacific Northwest underneath spruce, but there is less history of the practice in mid-Atlantic hardwood forests.
The superintendent of McCormick Farm, David Fiske, and Forestry Extension Specialist for Virginia’s Northern Region, Adam Downing, as well as Augusta Extension agent Booher gave visitors some insight into how the project was designed and is progressing.
“This is not just a loafing area,” Fiske said. “It’s not just shade, it’s also forage.”
Prior to the establishment of the project, the site was fenced off to cattle. There was also very little tree regeneration, as the undergrowth was thick with choking growth of invasive multiflora rose and spicebush.
To make way for pasture, that underbrush was removed, along with about 50-percent of the original basal area (a measurement of the tree stocking rate).
In hindsight, Downing said, he would recommend thinning trees to 60 to 70-percent of the original basal rate, because some of the remaining trees are showing epicormic sprouting, where branches come out of the trunk of the tree, potentially reducing its eventual timber value. “You can always come back and remove more trees later,” Downing said.
The primary species remaining in the timber stand are ash and walnut, which are good for silvopasture, because they have a good leaf canopy pattern, allowing a lot of light to reach the silvopasture floor. They also have a late leaf-out and early leaf-drop that is also good for silvopasture.
That said, when developing silvopasture from existing woodland, “you work with what you have,” said Downing.
It is possible to develop silvopasture, using either hardwood or softwood species, from existing pasture. For more information on whether to incorporate silvopasture you’re your farm strategy, consult your local extension agent.
Or stop by McCormick Farm and see for yourself how the silvopasture project is progressing.