One of the most important issues related to cover crops is termination. Cover crops are great – until they compete with cash crops for nutrients, water, sunlight, space, etc. In a normal field situation a farmer will plant one cover crop or at least a single mix. In our case we had four different cover crop “treatments” to contend with. Despite this, we didn’t have any trouble terminating the cover crops in the entire area with a single herbicide mix.
The herbicide application we used was a burn-down of 1.5 lbs active ingredient(AI) glyphosate with 1 oz Sharpen (saflufenacil) sprayed/broadcast on April 16. There is little residual activity with this mix however, as you can see from the picture, it was very effective in terminating the cover crops as well as taking care of what weeds were present – which weren’t a lot, from what I saw, mainly chickweed and dandelion though I didn’t scout the field after the March 24 field day.
In 2014, the last time this field was planted in soybeans it had quite a bit of marestail (sometimes called horseweed, Latin name Conyza canadensis). In central Indiana marestail is often glyphosate-resistant and even when it isn’t, control becomes difficult once it gets above 6 inches tall. For this reason we will be using a Liberty variety of soybeans once it becomes dry enough to plant.
It’s been cold and wet here for the past couple of weeks but we were fortunate to have some warm weather right after the burn-down which certainly helped with that application – as a general rule, daytime temperatures above 50 degrees for several days after herbicide applications increase the effectiveness. According to the National Weather Service daily highs in Indianapolis were at or above 80 degrees on April 17 through 20 (and 77 on the 16th), nearly ideal conditions. Hopefully things will dry up so we can provide a planting update in the near future.
We had a very nice turnout for our March 24 Field Day. We had a total of 24 at the program, 19 farmers, which we were very happy with.
Unfortunately the weather didn’t allow us to be outside that day but we anticipated this might happen and had taken quite a few pictures the day before when we were digging pits and we also had a couple of soil cores taken from fields which had long-term cover crops plantings. As a fringe benefit, we may have gotten a few additional attendees as nobody could do field work.
Our main speaker for the day was NRCS Soil Scientist Mike Wigginton. Mike went through what he found at the pits and discussed the impact cover crops have on soil fertility and health. A substantial part of the morning involved group discussion, almost a round table where farmers shared their experiences and knowledge.
We dug six soil pits and here’s a short summary of what was found. Keep in mind that last fall was the first time cover crops have been planted in this area.
We had two different cereal rye plantings. One strip was planted on September 29 and the other was planted November 4. One of the farmers on our advisory committee suggested the late planting of rye to demonstrate how, even if conditions keep you out of the field until late, you can still get a good cover crop stand. The plots demonstrated this nicely. In the earlier planted cereal rye Mike found roots to 32″ deep in a pit with a dense till (glacial till) layer at 36″. He found roots to 33″ deep in the late-planted cereal rye strip.
Mike found roots 36″ deep in the Annual Ryegrass strip. As expected, there was also a large amount of roots in the top few inches of the soil profile.
Oats-Annual Ryegrass-Crimson Clover:
This plot was one of our mixes. The oats winter-killed and the clover was just barely starting to come back so most of what was present was annual ryegrass. This was one of the shallower soils with a dense tillage layer at 27″. Mike found roots to 22″. This strip is one where it would be interesting to come back in a few weeks to see how things progress.
The oats and oilseed radish both winterkilled. We had a very dry month or so after planting last fall and didn’t have a lot of top growth though our germination was good. This was another shallow soil with glacial till starting at about 25″ deep. One of the interesting things Mike showed us was a permeable area indicated by soil color. This is a point where a cover crop root could penetrate and, over time (a long time) could begin to change the soil structure.
We dug a pit at our no-till “check” just to provide a visual contrast to the other plots. As you can see from the picture, there are no roots anywhere, not even in the top few inches. Even though weeds (and there were some) have root systems, they were very shallow and don’t provide much of a benefit.
The soil cores were very interesting as you could see roots 5 feet below the surface (which was the depth of the core).
This was a productive day with a lot of information shared. It will be interesting to compare these pictures with ones from future years to see if we can find any changes in soil structure, texture, color, etc., over time. It is unrealistic to expect significant changes in just a few months – the color and texture in the no-till strip did not vary significantly from the others – but in a few years we may see quite a bit.
This is a reminder that we will be hosting a Cover Crops Field Day tomorrow, Thursday, March 24 from 9 a.m. to Noon (doors will open at 8:30 for coffee and donuts). The program will begin at the Boone County 4-H Fairgrounds Annex Building (the small building near the north entrance) in Lebanon, Indiana. If weather permits we will walk out and see soil pits in the County Education and Demonstration Area.
The forecast calls for rain and there is a chance that the weather will be bad enough that we’ll stay indoors. We dug the pits this morning and took a lot of pictures. We’ll also have some soil cores on hand. Even if it rains we’ll have a lot to talk about and will have the program as scheduled. We’ll just be talking about the pits from pictures rather than standing in the rain. If you are planning to attend please call the SWCD at 765-482-6355, ext. 134 or e-mail firstname.lastname@example.org.
You can find a flyer with additional information here.
We will be having a Field Day at our Education and Demonstration Area on Thursday, March 24. All of the details have not been set but we expect it to run from 9 a.m. to Noon. We will dig soil pits and a soil scientist will walk us through what’s been taking place beneath the surface since we planted cover crops last fall.
We will post additional information once we have all of the details set. For those who are interested, here’s a map of the strip treatments in the area.
As the picture shows, the four primary treatments for the cover crop plots are looking great, an inch of rain with warm temps has really helped. Today, November 4th, the last cover crop plot was planted, our “Late Cereal Rye” plot.
A planting date around November 1st is outside of the conventional wisdom for planting the majority of crops & vegetation used for cover crops, but Cereal Rye often demonstrates an uncanny ability to germinate under cold conditions and emerge in the early spring after late fall plantings.
Even with little or no vegetation over the winter season, late planted rye can establish root mass to enable it take off in the spring. While we may not have the winter cover protection we’d like to see, the root development can provide many benefits for soil health and fertility.
And sometimes, you need to do things outside the “conventional wisdom” just because that’s the way it ends up in the real world. It will be interesting to watch this particular plot.
We planted the cover crop plots with a No-Till drill, this allowed us to maximize soil-to-seed contact, while protecting the corn crop residue on the ground surface. We want maximum soil-seed contact to promote germination and fast growth, while protecting the crop residue to minimize soil erosion, keeping valuable soil & nutrients in our field, where it belongs.
The picture was taken on October 29th, roughly 30 days
after we planted the plots. Considering almost zero rainfall for 4 weeks, the cover crops are looking good. The 1 inch plus rain in last couple days has given the cover crops a kick start, the moisture combined with moderate temperatures in the 10 day forecast should enhance growth into November.