by Deborah Jeanne Sergeant
To help farmers make better use of their woodlands, Michigan State University Extension educators Julie Crick and Kable Thurlow presented “Agroforestry: Silvopasture Options” as a recent webinar. Crick said agroforestry includes five practices: forest farming, silvopasture, alley cropping, riparian forest buffer and windbreaks.
“Agroforestry is a natural resource management system that through the integration of trees on farms and in the agricultural landscape diversifies and sustains production for increased social, economic and environmental benefits for land users at all levels,” Crick said.
She offered as examples for forest farming growing food, herbs or decorative crops under the forest canopy, where plants that need shade and humidity do well, such as mushroom logs or ginseng.
Alley crops between rows of trees can provide shade and preserve more moisture for plants. Riparian forest buffers have ecological benefits, including reducing soil erosion and runoff while providing a more natural means for wildlife to transverse farm landscapes instead of going through fields, which may cause damage.
Similarly, windbreaks “interrupt the flow of wind along the landscape to protect crops, buildings and animals,” Crick said. Also called shelter belts and hedgerows, they’re planted in a staggered pattern to offer more protection.
“Long term, trees could be harvested,” Crick added.
Silvopasture represents yet another way farmers can use trees.
“Silvopasture is where trees, forages and livestock production take place on the same piece of land over a long period of time,” Crick said. “It’s a sustainable, synergistic system where none of the resources are managed to the detriment of the others.”
Because silvopasture is more than fencing in the woods and turning the cows loose, Crick recommended meeting with a forester who can help create a plan for making the area suitable for grazing.
She said farmers have two choices for creating silvopasture: planting trees in an existing pasture or planting forage in an existing forest. “A silvopasture needs forage, fencing and water,” Crick said.
Farmers must also clear brush under the canopy and clear out any toxic plants while providing what the animals need to eat. They may also need to cut some trees out to ensure enough sunlight reaches the forest floor. The basal area is the “footprint” of one tree at about four feet off the ground. In one-tenth of an acre, a good silvopasture should have between 30 and 90 square feet basal area to achieve the ideal between too little sunlight and too few trees.
Kable Thurlow said silvopasture has three integrated parts: tree/shade management, forage management and livestock husbandry.
“Silvopasture is not turning cows into the woods and leaving them until everything is eaten,” he said. “It’s not destroying the trees. It’s not degrading the natural resources. It is about enhancing and improving forests, forages and livestock production.”
The old paradigm was to keep the herd out of the woods. Thurlow said silvopasture is breaking this old paradigm. He also said silvopasture isn’t just a tree or two in the pasture for shade.
“If you allow livestock to have access all the time to shaded areas, they’re going to congregate around there and you’ll have a lot of nutrient deposit there that would benefit you more if it were more evenly spread out over the pasture,” he said.
As with standard pastures, farmers can choose from different grazing styles: set stocking/continuous grazing or rotational grazing. However, with poorly managed rotational grazing, farmers tend to let animals under-graze and over-graze different areas.
“If you’re doing rotational grazing, you can spread those nutrients over all the pasture,” Thurlow said. “Pastures are excellent forage sources if managed properly.”
Of course, it takes time, planning and effort to move animals. With set stocking or continuous grazing, the animals stay in the same pasture for 90 days or more. The farmer doesn’t have to move the animals and they use one source of water. With low enough stocking rates, the farmer can have modest gains with the animals.
But Thurlow pointed out that set stocking has some disadvantages, including decrease in pasture productivity, concentration of nutrients in certain areas, risk of runoff and erosion and additional costs for reseeding because of over-grazing.
Simple rotational grazing with two to four paddocks requires moving the animals every 10 to 90 days. With fewer water points, it’s easier to keep the animals hydrated.
“They will have the same problems as the set stocking,” Thurlow said. “They will just happen at a slower rate.”
Management intensive grazing means moving the animals every one to nine days. Thurlow said this can improve the plant community and allow for an increased stocking rate over time. But farmers will need more effort to keep the animals moving, including more fences – although some can be temporary.
Thurlow recommends 10 head of animals per 10 acres for a stocking rate for continuous grazing.
He added that silvopasturing is intensive rotational grazing. Farmers can strategically plan to use their silvopasture to provide animal comfort, not only during July and August, when shaded areas are preferable for animal comfort, but also during winter months when the wind block helps animals that stay outdoors year-round. Thurlow said bale grazing can help feed animals during the winter while they’re on silvopasture.