Spring of 2016 came early this year, giving a jump-start to summer annual weeds. The summer of 2015 was ripe with rain, weeds and the inability to get them sprayed. Many of those weeds matured enough to set seed, significantly increasing the seed bank. That is creating weed problems now. Pasture and hay meadow weeds are significant profit-stealing problems that affect grazing patterns and decrease tons of usable forage per acre. Anything that decreases tons of desirable forages also reduces pounds of beef per acre and negatively changes the bottom line of your operation.
The most efficient plans for weed control target the early life cycle of the target species. Efficiency has become somewhat of a “buzzword” as we contemplate a blossoming population and increased need for the beef people will want to eat. Efficiently increasing the pounds of beef per acre on your operation contributes to feeding our population.
For biennials (thistles, spotted knapweed, etc.) and winter annuals (henbit, chickweed, etc.) I recommend spraying in late fall through very early spring. Just choose a day with temperatures over 45 degrees and unfrozen ground. Two pints of GrazonNext HL per acre plus Astute at one quart per 100 gallons of solution will control emerged weeds—and the residual activity will help to control weeds not yet germinated.
Most summer annuals can be controlled with a herbicide application at the very beginning of their life cycle, even before some have emerged. For example, if you had a severe problem with ragweed (our biggest thief of moisture and nutrients in the summer) in a particular pasture last year, it has likely returned this year. Spraying a product with residual at the first sign of ragweed, or even slightly before, will control that weed population for most of the growing season. For this application to be most effective, grass should be grazed short so that herbicide can reach the ground. It will quickly regrow if moisture and plant food are available.
Another important management practice that will add to efficiency is to move cattle to new pasture when grass is grazed down to about 3 inches. This rotation strategy applies during the growing season. Obviously, during times when grass isn’t growing (winter or severe drought) you are better served to hold them in one paddock and feed hay until grass growth resumes.
There are three reasons to move cattle at that 3-inch mark. First is that regrowth is much quicker when starting from the 3-inch mark. Imagine that each blade of grass is a solar panel. Continuously grazed grass tends to be about three-quarters of an inch tall and about quarter-inch wide. That provides a surface area of less than 0.2 square inches of “solar panel”. Three-inch tall grass tends to have a width closer to a half inch. The taller grass provides a surface area of “solar panel” closer to 1.5 square inches (more than seven times larger). If moisture and fertility are the same, you can grow grass from 3 inches to about 12 inches faster than you can grow grass from three-quarters of an inch to 3 inches.
The second reason to move cattle at 3-inch grass is it allows the root system to recover carbohydrates more effectively. The result is a healthier stand of grass. You’ll benefit from pulling cattle at the 3-inch height in one other way—fewer ongoing weed problems, which will lengthen the interval between spraying.
Efficiency and a proactive management of grass does require some time and resources. Investment in your pasture/hay forages will pay off. In the words of a wise man that I admire: you can’t just save your way to a profit; you have to grow your way there.