By Jamie Martin
Recent research indicates that planting soybeans earlier in the growing season can provide yield advantages for farmers, even when fields experience minor crop injury from herbicides.
The study was carried out by Purdue University researchers during the 2024 and 2025 growing seasons. Trials were conducted at multiple locations across Indiana to compare planting dates and weed control programs.
Results showed that early-planted soybeans consistently produced greater yields than soybeans planted later in the season. Only one location experienced lower yields from early planting after cold weather damaged young plants shortly after emergence.
Researchers observed that early planting often resulted in slightly thinner soybean stands. However, these stand reductions generally did not affect final yields. In addition, residual herbicide treatments, including reduced-rate applications, did not lower crop performance when compared with programs that used no residual herbicides.
One challenge identified in the study was weed control. Early planted soybean fields contained higher weed densities at the time postemergence of herbicides were applied. This created more pressure on weed management systems throughout the season.
Researchers also found greater populations of troublesome weeds such as waterhemp, giant ragweed, and common lambsquarters in early planted fields. Increased weed numbers can raise the likelihood of herbicide resistance developing over time.
Despite faster crop growth and better canopy coverage, the earlier-planted soybeans did not provide enough additional shading to significantly reduce weed pressure.
The researchers concluded that early planting remains an effective approach for increasing soybean yield potential. However, producers should carefully monitor weed populations and maintain strong weed control programs to prevent future management challenges.
Photo Credit: istock-oticki
Categories: National