Fall burndown applications will enhance your weed control for the control of winter annuals, dandelion, perennial weeds and marestail (aka horseweed) for no-till corn and soybeans. Fall burndown treatments are most effective from early October to mid to late November. However, fall burndown will remain effective later if weeds are still green and not killed by a freeze. Keep in mind, weeds will die much slower with cooler temperatures. 2,4-D and Dicamba are less affected than Glyphosate with cooler temperatures and cloudy weather.
For those with stubborn marestail populations, fall germinated marestail start stem elongation much early then spring germinated marestail and are more difficult to control in the spring. Eliminating winter annuals in the fall will not only help with starting next spring cleaner, but will eliminate potential egg laying sites for Black Cutworm, Armyworm and host sites for Soybean Cyst Nematode.
Even if a fall herbicide is applied, it is important to apply another burndown and apply a residual herbicide in the spring. Then follow up, if needed, with a post herbicide.
Many times, a fall applied residual herbicide does not appear to perform better than a fall applied 2,4-D, Dicamba or Glyphosate alone or in combination. It’s probably more economical to save the residual herbicides for spring, where it is needed most and get more bang for the buck. Besides, some fall applied residuals may restrict you next spring with crop choice if you need to change plans.
Non-Residual Fall Herbicide Options
Marestail, Winter Annuals, Dandelion
2,4-D or Dicamba or 2,4-D & Dicamba
2,4-D-Best for Dandelion
2,4-D & Glyphosate
Combination of Grasses and Perennials
For tough or hard to control weeds it is important to be relentless and take every opportunity to manage. Fall treatments are a very important tool in managing weed control concerns. As always, read and follow the label on products you select and understand any restrictions for planting intentions next spring.
Let’s be clear: tillage destroys soil structure. We all know that tillage can loosen poor soil structure and compaction, but it doesn’t really create good soil structure. Good soil structure is formed by the presence of roots and other soil organisms, without disturbance, over extended periods of time. Think about that crumbly soil under long-time CRP, an old hay field, or on farms that are finding success with no-till and cover crop systems. For the most part, poor soil structure is formed by human disturbance. There could even be an all-around lack of soil structure. In these cases, the soil is concrete hard on the surface and is powdery when worked. In a year where you are probably testing the limits of what you should do, what should you watch for?
Too wet: If standing water in the field doesn’t give it away, soil will “ribbon” when squeezed in your hand. Tillage clods are large and the surface of the clods will have a smeared look. These large clods will lock up as they dry and be difficult to break in the future. It’s like a good sear on a steak that locks in the flavor, only we don’t plan to eat these soil clods. This issue could lead to lumpy soil that makes for poor seed to soil contact for many planting seasons to come.
Too dry: Soil will “shatter” with tillage, even in areas with little compaction. The edges of the clods will often appear sharp and ridged. Tillage in dry conditions can pulverize any existing structure and further release needed soil moisture.
Just right: Soil will be crumbly off the tillage implement and in your hand. The natural fracture lines of the soil clods will be visible. These are “green light” conditions. Realize that if soil compaction is not root limiting, you are probably just burning more fuel than necessary and creating a risk for more compaction. Of course, things like residue management and manure incorporation are also factors.
One of the most difficult parts of any business is accepting the things that you cannot control, but finding ways to manage around it. In agriculture, we definitely do not control the weather, and trying to manage around it is an ever-changing proposition. The 2019 growing season is definitely giving us multiple opportunities to manage around.
The age-old phrase “you need to make hay when the sun is shining” really drives home the point of time management. We only have so many hours to get a crop in, get it cared for and harvested, all while working around Mother Natures “opportunities” that are provided. The aspect of time management is made apparent to me when many of the farmers that I get to visit will indicate that they put on their crop nutrients (manure or purchased fertilizers) and crop protection products as soon as it is agronomically and environmentally feasible -- many in the fall or very early spring.
This management decision, to have a portion of their acres “prepared” for spring, allows them to put their crop in when they and Mother Nature allows/decides, while not waiting for an agronomy supplier to get there. This decision to plant when they want sets them up for a higher yield potential in most instances. This also gives them more time to factor in that half to full day, figuring out a hiccup or two on the monitor, planter or other equipment, without having the pressure of also trying to get a field fertilized.
The take home statement from this is, even having just one field ready to go in the spring, allows you more opportunity to be a step ahead in managing your operation and/or more time with loved ones.