May 15, 2009

Usually pastures develop weed problems because the existing forage stand was not thick or vigorous enough to out-compete invading weeds. The first step in developing healthy pastures with few weeds is managing them to be more competitive. This can be achieved through fertilizing, extra seeding, and especially well-managed grazing.

Concentrated, Controlled Grazing

Once weeds become a problem, though, implement control strategies. One technique is to heavily stock a pasture, maybe with a ten-fold higher concentration of animals per acre than usual, for a very short time. You probably will need to use temporary cross fences to create small enough areas to achieve these high animal concentrations.

If this is done while problem weeds are still young, many of them will be eaten readily. Weeds like crabgrass, foxtail, field bindweed, and lambsquarter make good forage when young. Animals even eat cheatgrass, downy brome, and sandbur when plants are young. Once the weeds form seed stalks, cattle will almost totally reject them. Be sure to remove animals while desired grasses still have a few leaves remaining so they regrow quickly and compete with recovering or new weeds.

Other Weed Control Options

Some established weeds aren't controlled easily with grazing. Clipping or spraying these weeds when their root reserves are low will prevent seed production and reduce weed pressure. These weeds will return quickly unless follow-up grazing management keeps your pasture healthy, vigorous, and competitive.

Bruce Anderson
Extension Forage Specialist