Because of the current supply chain-price issues with fertilizers and agrichemicals, growers are contemplating all potential crop options for 2022.  Although soybeans are not a preferred rotational crop for historical peanut growers, they are attractive to others because they are a legume and do not require much or any supplemental nitrogen.

The availability and price of herbicides such as Roundup and Liberty, the uncertain future of dicamba, the lack of reliable Enlist (2,4-D choline) soybean variety performance data for the Southeast, and premiums for non-GMO soybeans have potential growers searching for weed control options in conventional soybean systems. 

I would like to remind all readers of this column that soybean weed control, before the introduction of RR soybeans in 1996, was not perfect but not impossible.  Fortunately, I began my professional weed science career in 1987, so I fondly remember those “good old days.”

Soybean growers searching for conventional weed control programs must first ask themselves the following questions:

If the answer to these questions is 1) a lot and 2) yes/maybe, it is very unlikely that you will be able to grow conventional soybeans unless you are willing to aggressively commit to the use of wider rows, mechanical cultivation, and hand-weeding.  But, do you have the time, personnel, and/or cash for these?  The very real threat of PPO-resistance is the main reason why I have never been a huge fan of Valor (PRE)/Reflex (POST) herbicide programs in Georgia soybeans. Great weed control but poor resistance management. 

If you were growing soybeans in Georgia in 1995, the top 3 most troublesome weeds were sicklepod, annual morningglory, and pigweed. These very same weeds are still a problem today. But, I probably would also add tropical spiderwort/Benghal dayflower to this list. In 1995, the top 4 herbicides used in Georgia soybeans were Sencor/Lexone (metribuzin), Treflan (trifluralin), Classic (chlorimuron), and Prowl (pendimethalin).  All of these active ingredients are still around today in some shape or form but they may not be as effective on certain weeds due to the evolution of DNA and ALS-resistance.

Assuming that you do not have PPO-resistant Palmer amaranth, here are my suggestions for weed control in conventional soybeans:

Weed control in conventional soybeans is very doable as long as PPO-resistance is not an issue.  With some thoughtful pre-planning, it might not be easy or perfect, but soybean growers should be able to get good enough weed control to maintain top yields. 

Wishing you the best of luck in 2022.  As always, good weed hunting!