How do we increase yield potential in 2016? Part 1: Weed Control

With the downward trend in commodity prices, our on-farm yield levels must be raised in order to be profitable. The best way to do this is by eliminating yield limiting factors, because once we start letting our yield slip backwards there is no method to recover what has been lost.

The best way to think about yield is in terms of “subtraction” and not “addition”. Every seed, in every crop, in today’s marketplace has the genetic potential to produce well above our common established on-farm averages. So why are we not producing 100+ bushel soybeans and 300+ bushel corn? The answer is simple: yield limiting factors.

They exist in every facet of production, from: weed control, nutrient imbalances or deficiencies, disease problems, insect damage, environmental stress, pH imbalances, and even the use of chemicals that plants can not properly synthesize.

Over the coming weeks, I will touch on each of these issues in a hopes of arming you with some knowledge of how to take your on-farm yields to higher levels.

In today’s blog entry, I am going to discuss weed control. Particularly as it has to do with resistant species and chemical damage to the desired crop.

Years after the first case of documented resistance in Mississippi, it has rapidly evolved into a major production issue. We have essentially created a monster by our dependency to rely on one chemical/compound and what I call rescue application approaches. Now we are left with weed species, like Palmer Amaranth, that are resistant to multiple modes of chemistry. This not only limits the tools we have at our disposal to eliminate these target pests, but puts producers in a position where it is now even harder to rotate chemistry for adequate control (due to decrease in chemistries available now).

I talk to a lot of producers on a daily basis who tend to always make a comment about how the chemical companies will develop something and life will go on as normal. The major issue with that train of thought is, that’s what got us in trouble in the first place! We can not continue doing things the way we have always done it, and treat problems the way we have always treated them. That is the definition of insanity.

Did you know that on average, it takes 10 years to create a new compound and get it to the market place? 10 years. The EPA and the changing landscape of public opinion is not helping us with this either. So, in the meantime, it’s wise that we protect the remaining chemistries we have left at our disposal.

The first place we should start is by determining what weeds we see on our farm, and whether there is any documented resistance of that species in Mississippi or a surrounding state.

The following link provides a list of resistant weeds in Mississippi and the chemistries they are resistant too.

Weed Species

Once we have examined what weeds there are resistance issues with, we can put together a plan of action in controlling these weeds by eliminating these chemical methods of control or by tank mixing these products with additional chemistries that still document adequate control. The more modes of action that we can use during a growing season, whether it be from tank mixing multiple chemicals or overlapping residual chemicals, the more it can help us in receiving the control we desire.

A good burn down strategy, overlapping residuals, and using effective chemistries can go a long way to protecting our yield potential by reducing nutrient competition during the growing season. We must pay attention to our labels when applying though. Some effective chemistries can produce a degree of crop injury – both visible and non-visible.

For example, metribuzin containing products (Sencor, Boundary, Authority MTZ) can cause soybean injury if the label is not followed correctly. Planting depth (1.5 inches or deeper), pounds of active material applied on a particular soil type, rainfall events, and days after planting are just some of the ways crop injury can result. This chemistry, even though it’s older, is still highly effective in helping us control resistant weed species, and with proper application, it can be used effectively without any resulting crop injury.

Newer products on the market, like Fierce, are products that can be highly effective tools for producers as well. A lot of these newer compounds can cause crop injury though if not applied properly. Many chemical representatives will tell you that the crop will grow out of the injury and that it did not cost you any yield reduction though, and that is simply not true. This should not keep producers from using these chemistries, it should just serve as a warning to make sure we use these chemicals properly.

I know this is a lot of information to absorb. Any producer wanting help with the process of planning a herbicide system, knowing which chemical actives can be sensitive to their crops, which chemicals can and can not be tank mixed, or even help with interpreting the labels, please do not hesitate to call me. I am in the office most days (Main St. in Marks) and can be reached by email at or by phone at (662) 326-8939.





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