Many emotions set in on farmers that hear the word “non-GMO”, but it could help them in times like today when prices are low for many farm products. As some may already know, non-GMO soybeans are being contracted in South Dakota at Miller by the South Dakota soybean processors. What could this mean for producers? It may mean a niche market for soybean producers to make a little more per acre when higher crop prices are needed. Some markets suggest that non-GMO soybeans can fetch a dollar or more a bushel than GMO soybeans. The big question that comes to mind with non-GMO soybeans is weed control. Is it possible to continue to farm No-Till and plant non-GMO crops with resistant weeds growing in your fields? The answer is yes with a little more homework a producer can control weeds and keep your soil healthy!
Non-GMO Soybean Weed Management:
These management strategies are not uncommon even in GMO soybeans. The basics are the same. First we always need a weed free start at planting. This means, do not plant unless the weeds prior to planting are controlled. To give you some time for a post application and to give your soybeans a head start, make sure to apply a PRE-herbicide before planting. Then apply if needed a POST-herbicide application when weeds are less than four to six inches tall after soybean emergence which may be anytime between two to six weeks after soybean emergence.
Burndown Herbicide Options
I can’t stress this enough with any crop, but you need to start with a clean field before planting. To do this use a burndown herbicide that controls a broad spectrum of weeds such as glyphosate, paraquat, glufosinate (Liberty®) before or at planting. Other herbicides that may add in weed control could include 2,4-D ester and a metribuzin product.
The biggest decision here is to choose herbicides that will give you a window to control early weeds and give your beans a head start. Examples of herbicides that may give you the best control depending on what weed pressure you have, could include: Authority Assist®, Authority First®/Sonic®, Canopy®, Valor XLT®, Gangster®, Metribuzin, Python®, Scepter® and Valor®.
It is best that weeds be controlled from two to four inches tall but never allow them to reach over six inches tall. Also use a spray volume of at least 15 gpa and nozzles that produce medium-sized droplets.
- Flexstar® or Rhythm® + Select®, Fusion®, etc (grass herbicides) + COC or MSO + AMS
- Other options could include FirstRate®, Classic® or Synchrony®. If applied with 28%, this may improve weed control but also increase crop injury.
- If necessary for late emerging weeds apply Phoenix® or Cobra® three weeks later if troublesome broadleaf weeds exists, add a grass herbicide if late emerging grasses are a problem.
Applications of herbicides in the fall are not as long lasting or effective compared to those applied in the spring. Never substitute a fall treatment for a spring treatment. There are options for fall application but usually they end up costing more and then a spring application is almost always necessary. One combination that may be an option in the fall may be glyphosate + 2,4-D or 2,4-D + a low rate of a chlorimuron containing product.
There are options that increase cash crop growth and decrease weeds as well those include: crop rotation, cover crops, row spacing and livestock integration.
Source: Gared Shaffer, South Dakota State University