For the last several years, we've grazed an irrigated pasture owned by Bud and Jean Allender. For the most part, it's outstanding pasture - a mix cool season forage (like Ladino clover, bird's foot trefoil and orchard grass) and some warm season grasses (dallis grass and johnson grass, mostly). We've also noticed an increasing abundance of two warm season invasive plants - smut grass and broom sedge. Neither of these plants is desirable from a grazing perspective. Smut grass doesn't produce much leaf material (it's mostly stalks for seed production), and broom sedge seems to be unpalatable to our lambs if it's reaching maturity.
|Day 0 - ready to graze after ~40 days rest|
|Day 2 - 1/3 acre paddock with 70 lambs|
This year, we've tried an experiment for managing these invasive species. After our first grazing pass with the lambs, we brought dry ewes into graze the most severely infested parts of the pasture. While we normally try to leave 4-6 inches of grass after we graze, we let the ewes take these plants down further - our hope was that a severe graze would allow more desirable plants to compete with the smut grass and broom sedge.
|Grazed broom sedge - June 27, 2013|
|Broom sedge - regrowth. Photo taken July 21, 213|
Normally at this time of year, we try to rest our irrigated pastures for 35-40 days between grazings. This gives the forage sufficient time to recover so that grazing will benefit the root systems of the plants. However, broom sedge in particular seems to recover from grazing more rapidly. Some of the broom sedge we grazed less than 3 weeks ago needs to be grazed again. We're seeing a bit more clover where we severely grazed the broom sedge and smut grass, but I think we'll need to graze this portion of the pasture more frequently to get a handle on it.
If you're a pasture geek (like me) and this kind of thing interests you, we'll be holding a pasture walk at this property on the evening of July 30. Go to http://ucanr.edu/sites/placernevadasmallfarms/?calitem=191658&g=22527 for more information!