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Select herbicides when you buy seed

What herbicides will you be using next summer? I can just hear you saying, “Why in the heck is he asking that when I just parked the tractor in the shed for the winter, and deer hunting is in full swing?”

I’ll tell you why: There is no question that weeds were more of an issue this past summer than previous years because the growing season was longer than usual, and more fields have glyphosate-resistant weeds. To meet next summer’s weed challenges, you’ll need to plan your weed control program carefully so that it coincides with your seed purchases this winter.

The use of preemergence herbicides is on the increase — and rightfully so. It is one of the best ways, in our tight cropping system, to introduce new herbicides into your rotation. The use of a preemerge herbicide allows longer flexibility for spraying in-crop herbicides and may replace one of the post passes as well.

I used a preemerge herbicide on all our replicated plots this past spring. The dry weather did not seem to hurt the weed control much. It appears chemical activity was reduced somewhat, but the fields were much cleaner than previous years. I attribute that success to the preemergence products.

Key Points

• Consider weed control when selecting seed this year.

• Consider using preemerge herbicides and the LibertyLink system.

• Liberty herbicide may be hard to get in the spring due to tight supplies.

LibertyLink soybeans, the newer herbicide-resistant cropping system, has grown in popularity, resulting in tight supplies of Liberty herbicide. I recommend that LibertyLink soybean customers purchase the Liberty herbicide well ahead of planting to ensure they have a supply available for their acres.

The Liberty system has proved to be a good tool managing resistant weeds, but it must be managed differently than glyphosate. Once again a preemerge herbicide is recommended, along with two post applications.

Volunteer corn will be another issue in soybean fields next season. With two fall seasons in a row of drier-than-normal corn, header loss during harvest has been higher than normal. Plants that grow from the kernels left in the field will rob your yield next year and cannot be left unmanaged.

Research by South Dakota State University has shown that 5,000 volunteer corn plants per acre can reduce yields by up to 20%, costing you nearly $140 per acre. Whether or not to control volunteer corn is an easy decision, considering it costs about $5 per acre to eliminate it.

Make sure to consider all your inputs this fall as you do your crop planning. Check into the various systems and products available for your area that can help you maintain clean fields. Doing your homework now will lead to higher yields next season.

Spelhaug is an agronomist with Peterson Farms Seed, Harwood, N.D. For more information, contact him at 866-481-7333 or

This article published in the November, 2012 edition of DAKOTA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2012.