Keyline design can help silvopasture, rotational grazing strategies
WOODBINE, Md. — The butterflies were literally having a field day. Everywhere one looked, multiple species, including numerous monarchs, fluttered across the grazing fields of Keith Ohlinger’s Porch View Farm.
In light of the two-year decline of western monarchs as announced in both March 2019 and March 2020 by the Center for Biological Diversity, the prolific presence of not only butterflies, but also showy butterflies such as monarchs and swallowtails, speaks to the ongoing success of Ohlinger’s strategies to achieve his vision for his farm.
In a recent Future Harvest webinar, sponsored in partnership the Chesapeake Bay Foundation, Ohlinger shared some of those strategies.
Ohlinger’s presentation focused primarily on keyline design, sometimes also called keyline planning in recognition of the topographical plans that are developed to execute the concept.
Developed in the 1940s by P.A. Yeomans, an Australian mining geologist and engineer, keyline design uses a land’s topography to optimize and manage a farm’s water resources.
Citing P.A. Yeomans’s well-known 1965 book “Water for Every Farm”, Ohlinger explained that “‘one of the primary objectives of Keyline Planning is to enhance the swift development of deep biologically fertile [living] soil in systemically designed landscape.’”
“The goal,” he said, “is to conserve every drop of water that falls on the farm and create a soil sponge which replenishes the underground aquifer. It still moves downstream, just at a slower and more fully filtered pace.”
The keyline design also enhances Ohlinger’s silvopasture and rotational grazing strategies in raising his diverse livestock of Irish Dexter cattle, Gloucestershire Old Spots pigs and Hog Island sheep, along with an assortment of ducks, geese and chickens.
Along with keyline planning, Ohlinger defined for the webinar’s participants both the terms silvopasture, an agroforestry system where “‘trees, animals and forages for those animals are integrated as a whole system that is greater than the sum of its parts’ ” and rotational grazing, where livestock are intentionally “‘moved to different portions of the pastures, called paddocks, while other portions rest.’”
For instance, as part of his silvopasture strategy, last spring, Ohlinger planted more than 7,500 trees on his farm, placing most of those trees on one foot spacing along the keyline berms.
Created by digging out swales one foot deep every 100 feet to create a one percent drop across his farm’s 22 plus acres, Ohlinger’s hope is that the trees along the berms will “eventually be turned into living hedges in place of the [metal and post] fencing” he currently has in place to provide definition to the keylines.
As he explained the process for creating the keyline’s swale and berm system, Ohlinger emphasized “that what works for one farmer may not work for another.”
The 1-percent slope, for example, worked on his farm, but on a farm “with a steeper slope, you would want a swale with a lower bottom and a steeper berm.”
Finally, in a discussion during a later visit to his farm, Ohlinger acknowledged that the strategies — both keyline design and silvopasture — are not for everyone.
“It’s a hard transition,” Ohlinger said. “Plus, it’s not like there’s (just) one book with the exact blueprint to follow.”
“This,” he continued, “is the challenge constantly faced in agriculture.”
Toward that end, Ohlinger emphasized that farmers looking to put keyline design and silvopasture into place would need “to look at what your farm offers and spend some time out on your farm before you start laying keylines out” and committing your farm’s resources.