As we wrap up harvest and continue to apply fertilizer, a few questions have been received about whether we are entirely too late in the season to apply fall pre-emergence herbicides for the upcoming soybean season. The short answer is that agronomically- NO, we still have time. The issue may come down to more of an equipment issue than an agronomic one.
Many of our pre-emergence herbicides for soybean have a fall application label, and now can still be a great time to lay a solid foundation for weed control next spring and throughout the upcoming growing season. Most fall residual herbicides recommend application anytime soils are below 50F and continue right up to the ground being frozen and/or snow cover- so there still is time. As far as equipment- the concern obviously is the weather- and if we still have application equipment that is not completely stored and winterized. Nighttime temps are often below freezing, and freeze protection of pumps, strainers, sensors, nozzle bodies, etc. is a primary concern.
- Fall application provides the opportunity to control winter annual mustard species like pennycress or shepherdspurse as well as dandelion, thistles, and fall-emerging marestail. These weeds have not completely shut down for the season, and would still absorb a dose of weed control product like Roundup, 2,4-D or dicamba, if added to the residual herbicide. Control will not be seen this fall, but emerged weeds sprayed now will not likely regrow next spring. Downy brome and Japanese brome are also still somewhat active. The residual products also control seedlings of these weeds next spring
- Kochia and marestail often emerge very early in the spring. Laying a foundation with a residual herbicide now can limit early flushes of these troublesome weeds as well as others.
- Wheat Growers also has a Fall Residual Program for herbicides that is still in effect, allowing growers to defer payment for fall residual herbicides, if they so desire.
Fall residuals allow you to effectively manage a tough weed population next spring, and although time is short, there is still an opportunity. Take advantage of the relatively open fall to not only get fertilizer applied, but also get a handle on tough weed populations.
Thanks and have a successful and SAFE rest of the fall!