Benefits and Challenges of Planting Cover Crop Mixtures
Organic farmer collaborators in the “Cover Crop Cocktails” research project discuss why they plant cover crops and what are the benefits and challenges of incorporating cover crop mixtures.
- Hi, my name is Joseph Omcilly, a research rep at Penn State, for the past five years we've been working with a team of farmers, scientists and extension educators to learn more about cover crop mixtures.
For decades, farmers have been using cover crops to improve soil health and suppress weeds.
Usually just one cover crop is planted as a mono culture.
But recently, we've seen more and more farmers experiment with cover crop mixtures of three to more than a dozen species.
We've been using controlled experiments and on farm research to help farmers understand the benefits and challenges of using cover crop mixtures.
In this video, you'll hear our farmers and collaborators reflect on why they're using mixtures.
- We grow corn, soybeans, spelt and alfalfa hay, alfalfa grass mixed hay, those are the main crops we grow.
We also do do certified organic vegetables too but that's only about an acre, it's a small side business.
One of the main reasons that we're planting the cover crop is to try to get nitrogen production, have nitrogen for our corn crop that's gonna be planted into that ground.
So therefore, we're mainly looking at legumes in the past, trying to have the legumes produce as much nitrogen as possible and that's pretty much what we have done up until this point, I would like to look into doing mixtures more, adding in maybe other things like different grasses or other non legume plants that might scavenge and pull up nitrogen that's left from the previous crop and so we have kind of a combination of plants that are producing the nitrogen that we need and also other plants that are gathering the nitrogen that's left in the soil and providing that for the next corn crop.
Some then are also trying to look, looking at timing of what crops can be planted well together.
One of the things with our equipment, looking at our drill, we don't have, the grass box doesn't work on our drill so any mixture we plant, we wanna mix it all together and be able to plant it in one pass.
So therefore, we need to look at things that mix well and go through the drill well so we don't have to make multiple passes or try to get some other kind of equipment to plant the cover crops.
So some of those are some of the things we're looking at.
- We had been in the process of experimenting with lower input, reduce herbicide and mechanical weed control for several years before that, mid 90's and were able to see that we were not, we could get away with weed control, which was our biggest hang up, which most guys, it's the biggest hang up, to go in organic or to going without chemicals for weed control herbicides so that, we went into it and decided that we could do it and like I said, the first year was 2001 and then 2002 we were certified on all of our home acres here which is 270 acres.
I have seen a lot of improvement in the soils where we're using cover crops over just corn and soybean rotation and of course, after three years of alfalfa grass hay, it makes a terrific corn or Canola feeding crop.
And so the cover crops have a tremendous benefit as far as the root systems that they put in the soil which increase the organic matter and also produce nitrogen and green manure to be plowed down.
And on our rented farm, we're using some cover crops because there we don't put hay out so we usually have a small grain seeded in the spring and then after that comes off, then we'll put a cover crop for the corn then for the next year so I like a cover crop that survives the winter, it's not real expensive but I also like to have a small grain in there because I think that helps and we've seen that in this project.
It seems to help the survivability of the legumes into the winter and over the winter and then also the cover crop has to be something that reaches pretty much full maturity by the 10th of May.
If you have to wait till the 10th of June which is generally the case like with veg, is a little slower coming although there are some earlier maturing ones I guess now but the winter peas do that well.
The Crimson Clover does that well.
Even more so than the medium red clover as far as early maturity and reaching the peak of the nitrogen fixing ability and bio mass as early in May as possible.
- One of the main benefits I would say is just that depending on when you plant, what the climatic conditions are like, whether it's dry or whether it's wet, hot or cold, that can really affect which plants flourish and don't do well and so by having the mixture, it to me, again, like become an insurance policy, I like having a variety out there 'cause that way one year one crop might do a little better and the next year another crop might do better and so that would be some of the benefits and then of course, having the variety of different plants growing, having the different roots down there in the soil, I know that's benefiting the microbial life.
There's different things, like different plants that like variety and diversity and so having that in there I know that I'm giving a benefit to my soil by having a mixture.
And so those are some of the things I like about having a mixture and the fact that I know they're gonna be cycling different nutrients depending on their roots and different things like that.
The challenge again, though is trying to come up with a mixture that you plant the right amounts of each thing 'cause from what we noticed in the plots that we had, we had canola in a mixture and it tended to dominate and kind of choke out a lot of the other things, a lot of the other species of the cover crops that are in there so trying to come up with the right rate, I think is key and that might vary from each farm, I think, depending on where you're at in the state or in the region, and then also the weather at the time of planting, trying to come up with mixture, that's a challenge I think, is trying, that and having the equipment to be able to plant it all at one time so you don't have to go out there and seed two things, go back and seed two or three other things, just be able to plant it all at one time and be done.
- I think the benefits are that you might have some times, some seasons where one particular variety or one particular crop in the mix of cover crops either for lack or moisture, for lack of warmth or cold doesn't take off as good in the fall as it should.
You have some others that kind of fill in.
And I think that's maybe as much as anything, a really good benefit to the mixtures.
And again, we saw that in our trials.
We saw one cover crop mix be altogether just one basically crop in canola the other year.
And so I think that's one thing.
I think the fact that even if it's gets started good, maybe the winter's one way or the spring's another way and doesn't lend itself to one of the particular crops in that mix and so I think that's probably the main advantage.
I think the one challenge can be getting it seeded at the right depth, some seed, it's real small.
You might be afraid you're gonna get it too deep if you put it in as deep as some of the larger seeded mixtures so sometimes you have to maybe use a drill that has a small seed box and a large seed box and so it's a little more hassle putting the seed in that way and if you have to mix it all together, that's kind of a hassle too doing that.
But I guess for the little bit of time that it takes, it's probably worth it.
And I know nowadays, these cover crop seed guys are mixing 'em for people, puttin' 'em together, mixin' 'em up, however you want them configured in the ratio of one species to the next so there's ways that we're gonna be able to get around some of those things too.