Source: University of Nebraska CropWatch
If planting new alfalfa fields this spring, consider needs and costs when selecting traits.
Roundup Ready varieties will allow for easy control of most weeds, but easy weed control shouldn't be the only consideration. Not everyone has weed problems in alfalfa, particularly when alfalfa fields were rotated to a different crop after 3 or 4 years of production. If a good stand can be established using other weed control options, weeds don't become a big problem in alfalfa until stands get older and start to thin out.
It's also encouraged that cow-calf producers plant grass-alfalfa mixtures in their hay fields. Since Roundup will kill the grass, conventional varieties are more appropriate in these situations. Also, controlling weeds in alfalfa does not always increase hay tonnage. After all, weeds can boost yield, and sometimes weeds can be acceptable feed. In this instance, spending time and money to kill weeds may not be worthwhile.
This trait also may not be warranted when oats are planted with alfalfa and later harvested for hay or grain and straw. In this example, Roundup can't be used until after the oats have been harvested. If a good stand of alfalfa remains after oats are harvested, further weed control with Roundup or any other herbicide may not be needed.
This trait will cost approximately $2.50 per pound of seed, so when selecting alfalfa seed, consider whether the benefits will pay back the investment.