Originally published July 6, 2021
croplife magazine
Remember when 200+ bushel per acre corn and 75-100+ bushel per acre soybeans were believed to be a significant stretch? Today, thanks to the enhancements in germplasm and crop protection solutions, these kinds of yields are now more easily attainable. But there is no singular, easy way to sustain or continue to increase these yield figures as growers are tasked with doing more with less.
A practice growers should be looking at more closely is integrated pest management (IPM). For many, the concept’s name might not be familiar but some of the elements are. It’s not the end all, be all strategy to push the limits of yield potential but, in my opinion, it’s one piece we can lean into to help increase yields and profitability over time while enhancing the growing environment and stewarding our available technology.
Weighing IPM As a Tool in the Fight Against Weeds
Typically, IPM is more focused on insect management and the economic thresholds associated with different yield-robbing pests, but the core elements of IPM are applicable to other focuses, like weed management. Though there are a lot of similarities, there is one major difference we have to keep in mind when introducing IPM to weed science that differs from our approach to insects: There are no established economic thresholds for weeds. With weeds, it’s a numbers game. One female Palmer amaranth plant can produce over 100,000 seeds, and therefore the threshold grower should aim for is really perfection.
In addition to utilizing herbicides as part of a weed management strategy, cultural practices complement herbicide usage nicely. Narrow row spacing, for example in soybeans, has become a standard cultural practice to help manage challenging weeds. This is done because canopying quicker can save a third or fourth herbicide application. Canopy closure also reduces weed competition, late-season germination, and weed seed production. In a study the University of Tennessee conducted, they found that soybean yields were also highest in 15-inch rows, 62.6 bu/A, compared to 56.8 bu/A in 30-inch rows.
Another cultural practice that’s helping level up the yield game has been cover crops, which are garnering more and more attention. The use and reason for cover crops can vary from region to region, but in areas like Georgia they’ve been using cereal rye for years to battle herbicide-resistant weeds. In the circumstance of a no-till operation, cover crops can increase organic matter and play a role in managing difficult-to-control weeds like Palmer amaranth and barnyardgrass.
As someone who works in crop protection, we support IPM practices like these because they help growers be better stewards of the management tools they have access to, as well as help them be as profitable as possible. We need to continue to strive to be flexible with our approach to pest management and understand and learn these IPM practices to find ways to make our conventional and cultural tools work together better.
