The cold snap and snowfall we experienced right after Thanksgiving did put a thin layer of ice on some area lakes and it seemed as though any additional field work or fertilizer applications would be coming to a sudden halt. With the recent rise in temperatures and this continued warmer trend for the near future, may allow field activity to continue.
If by chance we do get back into the field yet this fall or early next spring, one of the “jobs” I would like to see get done is to put more pre-emerge herbicides down in front of soybeans. Historically we have had good weed control in corn, but in the last few years many soybean fields in our area have been difficult to achieve adequate weed control in. (As shown pictured below, and yes both pictures are soybean fields with Giant Ragweed in them.)
To steal a phrase from one of my colleagues “we do not live in a Glyphosate world anymore” which is partially true in that we do have weeds that are resistant to Glyphosate. Our reliance on one mode or site of action in our soybean crops have helped cause a weed shift from Velvetleaf, Cocklebur, Common Ragweed, Thistles and Quack, to more of a Tall Waterhemp, and Giant Ragweed mix.
The advantage of putting on a pre-emerge herbicide is, it does kill weeds and puts different modes or sites of actions in the weed control mix. The down side is that in some instances, these herbicides have to be applied prior to soybean emergence or injury may occur. This timing concern is amplified by weather issues such as rainfall or winds that are to strong which would prevent an herbicide application. When this takes place we tend to rely solely on Post Emerge herbicides which are effective but the level of weed control is reduced compared to a Pre-Emerge application followed by a Post Emerge application.
Whenever I think of weed control I am reminded of a Weed Scientist saying “an 80% control of a Pre-Emerge herbicide is still more effective than a 100% control of a Post Emerge” Remember when weeds emerge they are yield robbers in that they take water and nutrients away from your crop, clean fields equal higher yields. This is of particular urgency when dealing with Pigweed/Waterhemp species which can grow 2-2.5 inches/day.
Herbicides are tools in our fight to control weeds in our fields, it wasn’t too long ago that the only tools we seemed to have were cultivators and a crew using hoe’s to kill weeds and had water jugs waiting for them at the end of the row. Walking fields also seemed to be a good tool in regulating a child’s behavior, with that being said speaking as a survivor of these management tools, putting a Pre-Emerge product down now or next spring will give you a better ROI than a water jug waiting for you at the end of the row next summer.
