Managing for What We Want

At the highest point in our irrigated pasture, an old pear tree grows. The pasture had been an orchard at one time - and there are still remnants of these trees scattered throughout the property. Some trees (especially the persimmons) are still producing. Others, like this pear, have re-sprouted from rootstock and don't produce any edible fruit. All of them - bearing or not - provide shade for our sheep and our livestock guardian dogs.

Several years ago, this particular tree was surrounded by a jungle of milk thistle that grew taller than me. Thistles are often nature's way of taking up excess nutrients - in this case, nutrients deposited by the sheep who liked to sleep (and defecate) under the tree. Like most ranchers, I'm not fond of thistles of any kind - and milk thistles are especially nasty plants. But rather than worrying too much about killing these thistles (with herbicide or chopping) we decided to focus on what we'd rather have in their place. We decided to try to manage for what we wanted - rather than what we didn't want.

Our first step was to use the sheep to impact the site. We didn't particularly care what the impact was - the sheep could eat the plants or trample them into the ground. Trampling puts the plants in contact with the soil, which facilitates further breakdown by soil microbes. Grazing - well, grazing is also the first step in the microbial breakdown of these plants - in this case, in the ewes' rumens. We found that our sheep actually like milk thistle - spines and all. They stripped the leaves off the stocks and even ate the flowers.

The next step was to think about what we'd rather see growing on this hilltop. We decided we'd try seeding the site with something that would germinate and grow rapidly - we wanted to out-compete the thistle seeds that were still in the soil. We also wanted something that would be tasty and nutritious for the sheep. Even though this is irrigate pasture, we decided to try annual ryegrass, thinking it would germinate quickly and crowd out any thistles that did manage to sprout.

Now it's two years after we planted the seed. The sheep just grazed this paddock last

week. The ryegrass was waste-high - and there was only a single milk thistle plant under the pear tree. The sheep loved the ryegrass (I have video of them grazing it when they first came into the paddock - here's a link) - but they also stripped the leaves off the thistle plant.

We've tried a similar approach on some annual rangeland that we graze in the winter (before and during lambing) and in mid-summer (with dry ewes). There's a large flat that has consistently been overrun with yellow starthistle. The homeowner association has had an aggressive spraying program, but we convinced them to let us try an alternative approach with our sheep. In 2018, we grazed the site for 3 days with nearly 100 ewes - the before and after photos are startling. Last year we were a little late, and the impacts weren't as impressive. But this spring, there seems to be far less starthistle growing on the flat. We'll take sheep back there in two weeks - stay tuned for photos!

I don't think we've hit on a magic formula - there's no recipe for a certain number of sheep grazing at a certain density for a certain number of days. I also realize that not all sheep will graze milk thistle. But OUR sheep grazed the way WE manage them on OUR leased pasture did seem to control the milk thistle problem. The shift, for me, was in thinking about what we wanted to see in this pasture - not to worry about what we didn't like.