Purdue University Entomologist Ian Kaplan and Carmen Blubaugh, who earned her doctorate at Purdue and is now a postdoctoral research associate at Washington State University discovered that cover crops provide habitat for beetles and rodents that feed on weed seed and prevent it from becoming part of a “seed bank” in the soil. They found that fields planted to cover crops had three to four times as many weed seeds eliminated due to feeding as those without cover crops.
We had a great day March 30 for our Cover Crops Workshop and Field Day. We had 32 in attendance, 24 farmers and while we had to work around thunderstorms we did find a window where we could go out and look over the plots – unfortunately the soil pits had filled up with water from the rains.
The morning program included a presentation from Corey Lacey. Corey is a Purdue University graduate student working with Dr, Shalamar Armstrong on whether nitrogen taken up and stored in cover crops is available the following crop year. Research is ongoing with this but the ultimate answer is, “some is available but it will take more research to determine exactly how much.” Hopefully at some point there will be enough research where this impact can be determined more precisely. We also discussed termination, herbicide carryover, and how this can impact cover crop selection.
As there was a morning window when it wasn’t raining, we took advantage of the situation to head out to the plots. NRCS Soil Scientist Mike Wigginton discussed what he found at the plots and in the soil pits with attendees.
The pits had filled up with water from a combination of water infiltration (it’s been a wet spring here) and rain the night before so these pictures are from the day before when we dug the pits. I’m focusing on root depth because while top growth is nice to look at and offers some benefits, beneath the soil surface is where things are really happening. It may be difficult to see the roots themselves in the pictures so look for the golf tees. Keep in mind that cover crop roots:
Increase water holding capacity and infiltration by forming channels
Provide a pathway for crop roots to travel, allowing more access to water during dry periods
Provide habitat for soil microbes
Through decomposition improve soil organic matter and increase nutrient availability
Help break up soil compaction layers
In the case of legumes provide nitrogen fixation
The cereal rye plot had some good spring growth going on and there were very few weeds present. Mike found roots to 32 inches deep, down to the glacial till layer. As you can see from the picture, the pit started to fill with water running right above that dense till layer as soon as it was dug.
The second strip was planted to barley, rape and hairy vetch. The growth wasn’t quite as lush as the cereal rye strip but it was coming. Mike found living roots in the soil pit down to 26 inches, right above the glacial till layer.
The final strip with spring growth was planted to annual ryegrass, hairy vetch, crimson clover and rape. The rape and vetch were just getting going, the clover was coming in well but was still fairly small and the annual ryegrass had a lot of growth. Mike found a lot of roots in this pit, down to 36″.
One of the interesting “finds” was that even though short, crimson clover had already started nodulation meaning it was starting to add nitrogen to the soil. I have no idea if this will be a significant amount for the corn we’ll be planting but it will be something to look for this fall during harvest (as I type this we are planning to terminate on April 17 if the weather holds).
We always plant one strip to oats and tillage radish because this is a great mix for farmers just getting started with cover crops. Oats and radish both winter kill so it takes away any termination concerns. While you lose some benefit because of no spring growth, it still provides quite a bit. We did not dig deep pits for this or our “check” strip with no cover crops as we would not have found living roots. Keep in mind that last fall we planted the strips on October 18, well past the recommended September 15 date for both of these, based on the Midwest Cover Crops Council Selector Tool. The oats and radish did come up last fall but were pretty small. However even with this situation, the weed population was significantly less than in the straight no-till plots. The main weeds we found were dandelion, chickweed and purple deadnettle. Evidently, even though we planted later than recommended, the cover crops inhibited the germination of the winter annual weeds.
While we are not arguing that planting cover crops means you can do without weed control the next year (is anyone arguing this?) since purple deadnettle is a host for soybean cyst nematode (SCN), this mix, even planted late, may provide an advantage when planted ahead of soybeans.
While our plots are for demonstration and education, not research, I did find myself thinking it may be worth doing some weed counts in the future.
Following the plot tour we had a farmer panel featuring Zach Cain, a Montgomery County farmer, Clint Orr, a Clinton County farmers and Justin Mohler, who farms in Boone and Clinton counties. We had a good discussion. Much of it was on specifics such as planting equipment and setup, mixes that did and didn’t work, termination issues – really the nitty-gritty of cover crops.
This was a good day. I hope everyone learned a lot. On the evaluations several farmers said they intended to start planting cover crops and others mentioned new mixes they would try. Thank you to Boone County Farm Bureau for sponsoring lunch and, as always, to the many farmers, agribusinesses, lenders, etc., who have assisted with this project. I look forward to our next field day, sometime this fall.
Our next Cover Crops Field Day Will be held Thursday, March 30 from 8:30 a.m. to around 3:15 p.m. The program will be held in the Annex Building at the Boone County 4-H Fairgrounds, 1300 E 100 S, Lebanon, IN.
Speakers for the day include Mike Wigginton from the Natural Resources Conservation Service, Corey Lacey from Purdue Agronomy, Brian Daggy from Boone County SWCD, Curt Emanuel from Boone County Extension and a farmer panel featuring Bruce Guernsey, Zach King and Clint Orr. Topics will include a discussion of the financial benefits of cover crop, species selection, herbicide management, how cover crops can impact available soil nitrogen, and touring cover crop plots to discuss production systems and impacts on soil health.
The program has been approved as a Private Applicator Recertification Program (PARP). Lunch, sponsored by the Boone County Farm Bureau, will be provided. There is no cost except for a $10 fee for those seeking pesticide credit. Pre-registration is requested to help with meal planning. To register call the Boone County SWCD at 765-482-6355, ext, 134 or e-mail Sheryl Vaughn at the SWCD. Much of the program will take place outside at the field plots so participants should dress accordingly.
Sustainable Agriculture Research and Education (SARE) has funded the development of a series of videos featuring 23 farmers around the country discussing their use of cover crops and the benefits they’ve seen. Two Indiana and several Midwestern farmers are among those included.
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 email@example.com.
You can find a flyer with additional information here.