The main purpose of a pasture is to feed livestock with healthy grass, but weed invasion can cause serious issues for farmers. Weeds consume nutrients, water and light otherwise reserved for the grass, and these pesky plants propagate so rapidly that an entire pasture can be consumed in only a few seasons. When facing a pasture covered with weeds, properly apply herbicides to kill the weeds and leave the ground open for new, desirous growth.
Mix 2,4-D, a general herbicide, and water into a sprayer tank. The amount of herbicide and water you need varies depending on the size of your land; in general, you should use 4 lbs. of herbicide for each gallon of water.
Spray the weeds with the herbicide mix in spring or early summer, when the weeds measure between 2 and 6 inches high. This is the point when the weeds are actively growing and will absorb the herbicide. The herbicide should directly contact as many of the weeds as possible.
Spread grass fertilizer at a rate of 100 lbs. of balanced fertilizer per acre (or at your regularly practiced fertilization rate), distributed evenly across the area. The fertilizer will feed the grass of the pasture and help it thrive as the weeds die. As the grass grows, it will use more nutrients and water, depriving these from the weeds.
Repeat application of herbicide and fertilizer in the fall if necessary. You must apply both herbicide and fertilizer at least two weeks before the first frost of the season to ensure the weeds are weak and the grass is strong before winter weather sets in.