April 30, 2007 Agronomy

Control Weeds to Maximize Nitrogen, Yields

Research from the University of Missouri shows that early emerging weeds compete with corn in its developmental stages for available nitrogen (N) — and usually win.

In the study, when grasses were allowed to grow to 12 inches tall, they accumulated 16 to 50 pounds of N per acre. When additional N was applied to corn at sidedress before weeds were controlled as a replacement for lost N, the weeds accumulated an additional 10 to 16 pounds of N per acre.

N loss to weeds that are not controlled early adds up. At a cost of 33 cents per pound, 15 to 25 pounds of N used by grass instead of corn results in a loss of $5 to $8 per acre of N.

N loss to weeds also lowers yields. If that early weed competition results in 10 to 15 fewer bushels of corn, growers could lose an additional $35 to $52.50 of net income if corn prices are $3.50/bu.

Since early emerging weeds rob corn of the nutrients needed for maximum yields, eliminating grasses and broadleaf weeds in either Roundup Ready® or conventional corn is essential.

Grasses and broadleaf weeds are a threat to corn that you can control. Protecting your N investment by controlling weeds with soil-applied herbicides is a good foundation for success.