Our Summer Cover Crop Cocktail! Purpose, Seed Mix, Cost, and Method

We’ve got worn-out farm soil, and we’re trying to figure out the best, fastest way to bring it back to life so we can have very high-quality pasture for our future livestock. We’re convinced that diversity is key to rejuvenating soil. This post explains why and how we planted our summer cover crop cocktail.

Our summer cocktail seed mixture going into the no-till drill.

What is a Cover Crop Cocktail?

A cover crop cocktail is a big mixture of plants. Most cover crops contain just one or two varieties of plants. A cocktail contains many more. Farmers plant cocktails in order to capitalize on the synergistic effects of all different plants working together. Any cover crop is fantastic for soil health because nothing is taken off the field. All the biomass, roots, minerals, vitamins, and most of the carbon that plants accumulate during the growing season gets returned right to the soil in a much better, much more available form for the next crop to use and thrive. Cover crop cocktails amplify these benefits by adding DIVERSITY.

Why a Cover Crop Cocktail is Perfect for our Farm

Our soil’s most limiting factors are lack of organic matter (carbon) and biology. We have very few earthworms, even after 3 years of perennial grass. Organic matter is barely 2%, and it should be at least 5%. Compost and humates are great for adding organic matter to soils, but nothing sequesters carbon like a healthy plant, and cover crop seed is cheap!

Managed correctly, cover crops are guaranteed to add carbon to the soil, and DIVERSE cover crops are guaranteed to add lots of different carbon compounds to the soil via unique root exudates. Different plants leak different root exudates in order to attract particular segments of soil biology that help the plants thrive. Plants modify their environment. With a field full of diverse plants attracting diverse biology, the field can begin to accumulate all the needed components of a very healthy and fully functioning soil system. A soil system like this grows exceptional (nutritious and tasty) crops on less fertilizer and sequesters soil carbon (organic matter) like mad!

Our seed cocktail chart, click to enlarge.

Twenty Varieties of Seed!

I’m kinda embarrassed – we went a little crazy with our cocktail mix. Click the chart to see all the varieties we used, sources, and cost. We ended up with about 70 pounds of seed per acre (probably way too high) with 29% warm season grasses, 37% legumes, 14% brassicas, and 20% broadleaves by weight.
Warm Season Grasses: Big biomass creators, leak lots of carbon, associate with beneficial mycorrhizal fungi to sequester even more carbon. Varieties: sorghum and millets.
Legumes: Fix nitrogen (inoculated), associated with both mycorrhizae and benefical rhizobium bacteria. Varieties: cowpeas, soybeans, hairy indigo, sweet clover, alfalfa, sunn hemp.
Brassicas: Instead of associating with symbiotic bacteria and fungi, brassicas leak harsh acids that cleave off phosphorus and other minerals. For some reason, the acids really attract earthworms and other VIP soil animals. Varieties: camelina, dwarf essex rape, mustard, turnips.
Broadleaves: Highly associated with beneficial soil fungi, flowers attract beneficial pollinators and add to above ground soil diversity. Varieties: sunflowers, buckwheat, phacelia, herbs, safflower, chicory.

Pasture seeding – drilling cocktail seeds into existing pasture. Grass about 8″ high.

Cost

At $77 per acre, we didn’t do a good job at controlling cost. I’ve seen cocktail examples online around $30 per acre. I’m sure these cheaper mixes contribute great benefits too. Our mix does contain a few expensive perennial varieties for our future pastures, such as sweet clover, alfalfa, and chicory. If we were planting a row crop after this cocktail, we wouldn’t include these hard-to-kill perennials. So some of the $77 per acre will continue into future years.

Method

We rented our county’s no-till drill to plant the cocktail mix into 40 acres at a 1-inch depth.   We planted the weekend of May 18th.  Half of the acres were our own pastures, and the other half were our neighbor’s acres where we previously planted rye and vetch. For our pastures, we planned to rotovate to kill the perennial grass, but we ran out of time, became more interested in no-till methods because of this, and wanted to experiment with pasture seeding to see how the seeds came up. Also, reseeding perennial grass is expensive.

The drilling was easy, but mixing the seeds was a whole lotta work! We didn’t account for this beforehand. All the legumes needed different Rhizobium inoculants, and we did that in big bins. We also inoculated the grasses and broadleaves with mycorrhizae. We did a giant mix (all seeds went into the drill’s large bin) for each of the seven fields and filled the drill per field. We used an excel spreadsheet chart to get the right ratio and weight of seeds for every field.

Results

We got nice rains after planting, so the seeds germinated really quickly. Yay!!! The buckwheat and brassicas were up in five days, then came the cowpeas, soybeans, and sunn hemp. Millets came up after about 10 days. It’s now three weeks after planting, and the cocktail is nearly a foot tall in our neighbor’s fields. In our grass fields, the cowpeas and soybeans are just starting to rise above the grass height. The brassicas are following them. I’ll post an update later this summer. Thanks for reading!

The cocktail line-up coming up nicely through mow-killed vetch mulch. Brassicas, sunn hemp, cowpea, millets, buckwheat, soybean. Two weeks after planting. Neighbor’s field.

Soybean and cowpeas coming up in our pasture. Two weeks after pasture-seeding with no-till drill.

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6 responses to this post.

  1. Posted by Rich on June 14, 2012 at 4:10 pm

    How do you plan to manage this planting?

    Are you going to mow it at all this summer, or just let it grow to maturity this fall?

    If it was a wildlife food plot, I would think you would let it go to seed and then mow it in the fall so that birds like quail could get to the seed on the ground and possibly leave some of it standing so that you could get a volunteer stand the following year.

    If you were planning on planting something similar for grazing in the future, it might be worthwhile to mow some small strips at different times to roughly simulate a rotational grazing setup so you could see how the plants respond.

    Whatever you plan to do, it is pretty interesting to plant that many different plants at once. I thought I was being bold because I was going to throw all my leftover grain sorghum, sorghum-sudangrass, millet, soybean, and oat seed in the drill and plant it out in the pasture.

    Reply

    • Hi Rich, we planned on mowing it all in late August and then plant a winter cover crop cocktail. I know some of the summer plants won’t die until hard frost (learned that lesson with the sorghum-sudan last year!) so I figure we’ll get the winter seeds in the ground, and some of the summer plants will re-grow until frost kills them around Halloween here. But you’ve got me thinking about the strips – that’s a really good idea!

      The buckwheat is already flowering – i’m curious to see which other varieties will set seed before late August. The wildlife food plot idea is a good one too. I’ll talk to the hubby about that. I’ve never seen quail around here, would be very nice to see them. Correct me if i’m wrong, but isn’t a downside of the wildlife plot not having new green growing winter plants with living roots to shelter the soil bug populations through the winter? If i left all the summer plants standing, i’d just have dead roots in the ground during winter. Is this the right way to think about it?

      Please let me know how your pasture seeding goes. All our little seedlings are starting to poop out 😦

      Reply

      • Posted by Rich on June 14, 2012 at 11:02 pm

        If you are interested in attracting quail, from what I remember they prefer edges.

        Strips of standing cover next to mowed strips and even bare ground will provide the habitat for upland birds (and you also have to talk to them once and awhile by learning how to whistle “bob-white” in the spring).

        Combining quail habitat, a cover-cropping system, and grazing livestock isn’t impossible, but it will probably be more involved and need a little compromise at times.

        Leaving a few narrow strips around the edges of the field to go to seed to feed the birds might be worth it even if the soil isn’t as healthy as it could be (just rotate where the strips are each year). And, to my way of thinking, the quail, pheasants, deer, turkeys, bluebirds, and ducks are as desirable as grazing for the cattle. And, a healthy farm should have a diversity of wildlife to be healthy.

      • Hi Rich, totally agree with you on the “diversity of wildlife to be healthy”! That’s been the most noticable benefit of our cover crops so far. Most of our fields have a thin tree line around them, so it would be super easy to leave the cover crop standing around the perimeter too. I’ll definitely consider doing this come mow-time in August. Thanks for the feedback!

  2. Nice post. Have you thought about just mowing the crop with a sickle or similar to produce a sheet of mulch in the fall? We have had areas where I grew peas and oats, mowed with a mower conditioner to leave windrows, and then planted fall broccoli into the resulting mulch strips. The earthworm activity under the mulch was unreal. Remember, soil “uppens”…it does not deepen. New soil is made on the surface. I think leaving a sheet of mulch to decompose in place, rather than tilling in, would be interesting. Half and half as an experiment?

    Reply

    • Hi Jeff, thanks for commenting! Yes, we’ll be mowing to make mulch. We don’t have a sickle bar mower, but our bush hog makes decent mulch. I hear you on the earthworms! Makes me giddy! I had similar results in our veggie garden this spring – grew rye & vetch over the winter, then cut it at its base with a sling blade (good workout). Made lots of good mulch, and the earthworm numbers are still super high under there. Weatherman says we’ll hit 99 degrees tomorrow, so I’m so glad all our fields have a nice layer of protective mulch.

      I’ve pretty much converted to no-till. We rotovated a sorghum-sudan & cowpeas cover crop last August, and I was very unhappy with the results – destroyed soil aggregates, etc. I didn’t feel good about it. It was probably our inexperience with the rotovator and our very sandy, very low organic matter soil structure. No-till (mow-killing) seems to be a lot less labor, fuel and headache. And the mulch is a huge benefit.

      Reply

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