We all know there is nothing magic about how goats eat that instantly kills unwanted plants with a single grazing. So how is it that we can tell our customers that goats will help them control their weed and brush problems? By what mechanism(s) do the goats control vegetation?
We touched on this at the Affiliate Training & Conference in March, but here’s a more complete explanation that might help you communicate with your customers and the press.
Goats turn a jungle of vegetation into something much more manageable. Even one pass from a herd will reduce the space taken up by the unwanted vegetation, improving sight lines, reducing thorns that stick and vines that grab, and generally making the area a safer and more pleasant place to be. This allows customers to target their follow-up efforts. They can cut and treat exactly what needs it instead of indiscriminately chopping with machines and spraying herbicides.
Goats reduce competition for the establishment of better vegetation. Each pass from a herd of goats provides more space, sunlight, and nutrients for preferred vegetation trying to get a foothold. People’s “preferred” vegetation is often native vegetation. Plants native to North America (sorry, Amanda, I don’t know if this applies to Tasmania) evolved with vast herds of grazing animals. Consequently, they benefit from an occasional, short-but-intense grazing — the same affect provided by prescribed fire. The problem vegetation we’re called to control with goats is often non-native, invasive brush and weeds, which do not tolerate grazing well.
Goats minimize reproduction. Many problem plants reproduce by spreading seeds. When our goats eat the flowers and berries off of targeted plants, they significantly hamper the plants’ ability to produce viable seeds. When goats remove nearly mature seed heads from plants before they drop to the ground, the seeds are destroyed in the goats’ digestive systems. Each year our goats can eliminate the plants’ entire seed crop. There will still be seeds in the soil from previous years, but over time we can “burn out” the seed from the soil by letting the plants germinate and then grazing them before seed-set.
Goats cause plants to “stress out.” From the middle of each growing season until the end, perennial plants are using their leaves to collect sunlight and turn it into energy, storing it in their roots in preparation for the colder, lower-light dormant season. When spring comes, these plants must use that stored energy to produce new leaves so they can start collecting sunlight again. Right after full leaf-out, most plants are at their most susceptible. They’ve used most of their reserves to make new leaves and haven’t had time yet to collect a lot of sun. If we graze these plants in the spring or early summer, the vegetation will have to once again call on its root reserves to recover. Now imagine if we repeat the grazing in the late summer (when the plant should be storing energy for winter, not using it to survive), and then again in the following spring. It’s the repeated stress followed by forced recovery that can eventually kill a plant using goats and only goats with no cutting or herbicide. And, looking back to #3, a plant just worried about recovery and survival is unlikely to reproduce effectively.
So, there you have it — the main four mechanisms for controlling vegetation with goats. Of these, #4 is the least understood and often the hardest to communicate to people, but it’s probably the most important, especially when trying to get conservation-minded customers (who hate invasive plants, carbon monoxide, and chemical herbicides) to commit to large scale, long term projects.