If we're talking cover crops, I could keep a person up all night. Cover crops are truly amazing in what they can accomplish, and the number of different hats they can wear on the farm.
I've planted almost every cover crop imaginable on my acres in the last decade, but cover crops certainly aren't a new or novel thing to me. My family has been using cover crops for more than 50 years. What’s changed over the years is how we use them, and what we know about what they can do for us.
One of the things that changed our cover-crop strategy was when we started no-tilling in the early 1990s. Up to that point, we were regularly tilling the ground. When a 2- or 4-inch rain would come through, the hillsides would wash and create large gullies in our fields. We had to do something to put a stop to that, and no-till seemed to be the answer.
As I've worked on my no-till and cover-crop systems, I’ve seen my soil organic matter increase from 0.81% to 3% to 3.5%. Water infiltration has improved, erosion has come to a halt, inputs have been reduced, crop roots are stretching far into the soil profile and yields have risen.
It’s taken a lot of trial and error to make everything come together, and we’re still working on it. But no-till and cover crops have made a huge difference on our farm.
Tradition To Trial
I remember my uncle using cover crops on our farm well before I started farming in 1964. They weren't really using cover crops the way we think of them now — they served a purpose. The covers, usually red clover, were baled for hay or grazed and then tilled under for the nitrogen to grow corn.
This was before we had the option of anhydrous or no-till, and we needed the nitrogen. The rotation was soybeans, wheat, red clover planted into wheat, and then corn.
By the 1970s we started moving away from cover crops because we had options for synthetic nitrogen and better options for chemical weed control. But what we didn't have, it turns out, is good soil structure.
In 1983 there was a big drought and we just happened to be burying a fencerow. We had dug down about 5 or 6 feet and were surprised to find that despite the drought there was moisture just a foot down. I had to ask the question, ‘Why aren't we getting to that moisture?’
The reason it was sitting there unused was that I had a plow pan about 6 inches deep in the soil profile that restricted roots from accessing that water. And we really needed it.
We looked to the University of Illinois for solutions. In a study they had tried a subsoiler and a deep ripper, even incorporating straw with those processes, but in a couple years they were right back to square one. The soil would run back together.
I had heard about no-till and was kicking around the idea as a solution. Then in 1992, we had a bad drought again. But in one field of corn, part of the field was good while other areas were terrible. We went out with a backhoe and dug 200-foot long trenches 3 feet deep that crossed through the good and bad corn.
In the bad corn, which was only going 20 to 40 bushels, there was a plow pan. But in the areas where the corn was good there was no plow pan, which meant the corn was getting through to deep moisture.
This really kicked me into gear with the idea of no-till and cover crops, so I decided to give it a try.
Once we started no-tilling in the early 1990s, we put cover crops back in the mix, too. At the time there hadn’t been much work done with no-till and cover crops, so we were just stumbling along, not really knowing what we might accomplish.
Our first goal was to break up the plow pan and manage the moisture better to help us get through dry spells. We wanted a very deep root on our covers to serve that purpose. We started with hairy vetch, buckwheat, spring oats and cereal rye. There were some beneficial relationships between the plants in the mix: For instance, it seemed like the oats would just make everything else grow better.
The hairy-vetch roots would go down about 2 feet deep, which was a good start. But when we tried annual ryegrass, we really tapped into the soil. The ryegrass would break through the plow pan and put roots down as deep as 6 feet. It didn't take long for the corn roots to follow suit.
Now that we've been no-tilling and doing cover crops for years, we don’t have a plow pan — it’s gone. The corn roots follow the annual ryegrass root paths and earthworm holes down 3 feet or more, tapping into that deep moisture and nutrients. When dry spells hit, our corn looks great and it doesn't roll. It can go about 4 weeks in dry weather without looking rough.
Every year our roots grow deeper and deeper and our corn seems to get better. Anywhere I dig on my farm, the corn roots go down 3 to 5 feet. That’s the whole idea of continuous no-till and cover crops.
The most important thing with cover crops is you've got to know how you’re going to control them. You don’t want your cover crops to get control of you.
The perfect control plan changes depending on the cover crop, what you want to accomplish with it and what your planting equipment can handle. If you are unsure of your equipment, you need to kill the covers when they’re young so you don’t get in over your head.
I’ve been over my head a time or two with cover crops, especially hairy vetch. When it’s allowed to grow for a while in the spring, it gets really viny and tough. I found out quickly that if I’ve allowed it to get to bloom that I have to forego my normal Martin spiked row cleaners. The vines would get on those row cleaners and wrap and wrap.
In this case I remove the row cleaners and let my double-disc openers cut through the hairy vetch.
One thing about my 16-row John Deere 1770 no-till planter that helps with planting into cover crops is that it’s hydraulically driven. All the moving parts are up above the row unit — there are no chains for the cover crops to get caught up in and cause problems.
My normal planter setup is fixed Martin row cleaners, double-disc openers, Keeton seed firmers, Martin spading closing wheels and drag chains. The machine also has openers to apply fertilizer 4 to 5 inches off the row so I don’t hurt my germination with the amount I’m applying.
When you only plant one cover, it’s easy to decide when to control it. You evaluate what the cover has done, and what you wanted it to do, and spray it at the point your equipment can handle the residue.
But I’m usually planting mixes, which can complicate things. For example, in September I planted cereal rye, radish, buckwheat, hairy vetch and spring oats. The radish, buckwheat and spring oats winter killed, but that’s OK because those crops had already done some good.
Cereal rye and hairy vetch grow until spring and can both produce a lot of plant matter, so I have to be careful letting them grow too long together. But I want the nitrogen benefit from the hairy vetch.
In this situation I use a grass herbicide to control the cereal rye in late April when it’s about a foot tall. The cereal rye has done a good job securing the soil and improving soil aggregation, but it’s not so large that it will form a dense mat that can sometimes keep the soil a little too wet for planting.
By controlling the cereal rye and leaving the hairy vetch to grow (and use up some extra water) I’m able to plant at a reasonable time.
The longer I let the hairy vetch grow, the more nitrogen I get from it. Depending on the weather, I will spray hairy vetch with 2,4-D right before planting. Or, if it’s a wet year, I’ll let it grow to manage moisture and control it after the corn comes up. Once it blooms it gets tougher and I have to re-work my equipment, so there are several factors in that decision.
As for planting, I try to plant my cover crops while it’s still a good time to plant wheat — that’s my guideline. Some covers can be planted later and grow well, but other times they don’t.
I usually stop seeding hairy vetch and annual ryegrass by early October, while radishes and oats usually aren’t planted after September 25. Cereal rye, however I have planted all the way up to December with good luck.
This year I seeded 700 acres of cover crops with my CrustBuster drill. Drilling is really the best way to go. I will plant after corn and double-crop soybeans.
Consider The Source
I’ve had a lot of help figuring out how to make cover crops work on my farm.
Mike Plumer, a retired University of Illinois Extension educator and conservation-ag consultant, has worked with me since 1996 establishing cover-crop plots on my farm, evaluating what works best, what cover crops can accomplish, and how to best manage them.
One cover we've worked with is annual ryegrass. We found that it was essential to get the right type of ryegrass seed for our climate. When we first seeded it, we tried 10 species and only three survived the winter.
Once we narrowed down which ryegrasses worked the best, we found they also had a better chance of survival if we planted them in a mix. I've had success with annual ryegrass and crimson clover, and ryegrass, hairy vetch and radishes.
I usually try to kill ryegrass pretty quickly in the spring. When I dig roots in early April, I usually find that even though there’s only a couple of inches of growth on the top, the ryegrass roots have dug down 3 feet or more.
I can terminate the ryegrass young still knowing I've got the full benefit and won’t have it getting away from me.
Getting the right variety comes into play with control as well because some varieties come out of dormancy at different times. If you have a mix, you might spray once and think you’re done, and then the other one wakes up and starts growing 2 weeks later.
That’s why it’s important to get cover-crop seed from a trusted source, specifying your variety and ensuring there aren't mixed varieties. Know what’s in the bag.
One thing that really gave me a boost with no-tilling into cover crops, especially cereal rye, was fertility placement. When I started placing fertilizer below and beside the row is when no-till really started working better.
I started with the No-Till system and tried several things over the years. What I've finally settled on is the following system:
I use a starter fertilizer put directly in the row with a drop tube. The starter includes trace minerals to which I add zinc and 2.4 ounces of Capture insecticide. The insecticide is a preventive treatment for cutworms and has done a good job. But I’m concerned about what it’s doing to my earthworms and soil biology. I may discontinue using the insecticide in the future.
Off to the side of the row I use a fertilizer opener to place 32% nitrogen, 10-34-0, ammonium Thio-Sul and Accomplish, a biochemical fertilizer catalyst from Crop Production Services. It helps make phosphorus in my soil more available.
Since I started doing this, my fields have woken up and no-till has really started working for me and I've been able to drop my nitrogen rates a bit. It depends on the cover crop used, but I've been able to reduce nitrogen rates between 20 and 50 pounds.
A Peer Boost
Since I adopted no-till and cover crops early on, it was easy to feel like I was alone in the endeavor. That’s where attending events like the National No-Tillage Conference really helped me.
There was the obvious benefit of learning about different tools and strategies, but I got even more from these meetings than learning new farming tricks.
I felt like I was doing something right by no-tilling. But hearing other people say the same thing helped build confidence that I was doing something worthwhile — something worth the extra effort and curious glances.
Now you hear people talking about no-till and saying it’s the only way to farm, but when I started out that wasn't the case. We didn't know what no-till could do for us — we were just doing our thing. It feels good to know you have other people out there facing the same challenges and getting great results.
With no-till and cover crops you can’t look at 1 year of results and measure the benefits. Working with continuous no-till and cover crops is like putting money in the bank: You add a little money to your account every year, and the more years you do it, the more benefit you get.