The Ultimate Winter Cover Crop Cocktail – and Why We Planted It

We planted a big mix of winter cover crop seeds on 29 acres on September 14, 2012.  This was our fourth consecutive cover crop planting.  Faced with delay in full-time farming plans and getting livestock, we’re trying to use the time wisely and improve our burned-out soil so it will make high quality grass for our future livestock.  Planting cover crops is essentially “Plan B” farming for us.  And yay, it’s working!

Winter Cover Crop cocktail seedlings 2.5 weeks after planting. Oats, tillage radishes, lupine, winter peas, cereal rye.

How Our Soil Needs to Improve

We’re located in Southern Maryland, close to the Potomac, on very sandy soil.  Charles C. Mann’s new book, 1493, has a map of the Eastern seaboard titled “Deforestation of America, 1500”.  Our farm is clearly located in the large coastal area that was cleared by the Eastern Indians for farms and villages probably 500 to 600 years ago.  This history, combined with centuries of hard tobacco farming, explains why our soil is so poor.  So we have a lot of work to do in the soil improvement department!  And we’re using plants (cover crops – nothing is removed from the field) to help.  Here’s our wish list:

  • Double Organic Matter:  Soil tests say it is barely 2%.  We want 4%.  We know this takes time, and we’re using particular plants that have huge root systems to help.  All plants ooze sugary compounds out of their roots to attract a beneficial microbe community, and some do this more/better than others.  The root exudates are complex forms of organic matter, the roots themselves will eventually decay into organic matter, and microbes help speed up the growth and decay cycle.
  • Chocolate Cake!  Yummm… but I’m talking about soil structure.  We want dark, loose, crumbly soil that smells good.  Large pore spaces let air and water percolate through and provide a luxury living space for those essential soil microbes and bugs.  When we first got this farm in 2008, the soil was depressingly dusty and crusty.  The soil structure has improved significantly – we now see nice aggregates – but we still have a long way to go.
  • Big Fat Adult Earthworms:  I have sadly never ever seen one of these in our fields.  We are thankful to now have earthworms (we didn’t in 2008), but they are small and skinny.  Adults with orange collar bands reproduce and are an indicator of good soil.  We are planting particular cover crops that entice the big guys.

    Our soil structure in September 2012. Improving aggregation but still not chocolate cake.

The Ultimate Winter Cover Crop – Explained

Following on our good experience with our summer cover crop mix (cocktail), we chose a winter mix of some of the best plants that meet our wish list items:  Austrian Winter Peas, Oats, Cereal Rye, Sweet Blue Lupines, Crimson Clover, and Tillage Radishes.

Winter 2012 Seed Chart – rates and prices

Rye and Oats:  These cool-season grasses have large root systems where soil microbes and bugs can hide out over the winter.  In the spring, rye’s growth will really take off and produce good, lignified (carbon) biomass.  The mowed clippings will make great mulch to protect the soil from hot summer temps.  The microbes, root masses, and high carbon mulch will all work to boost soil organic matter.

Legumes:  This will be our first experience with lupines, Austrian winter peas and crimson clover.  We inoculated these three to give them the best chance to produce nitrogen for the soil.  On top of the N benefit, this site says lupines have an aggressive taproot that will improve the lower soil profile.  Crimson clover has fine roots that help build a mellow soil structure (chocolate cake) and attract soil microbes.  I’ve heard that winter peas might be one of the best plants for mellowing soil, and they provide good amounts of tender biomass in the spring.

Brassicas:  Tillage radishes are mighty soil-moving machines.  They drill down into the soil profile and will even root down past compaction layers, opening up the deep soil to let air and water percolate through.  Our very sandy soil doesn’t have big compaction problems, but getting plants that go that far down – typically over 30” – is all good for any soil.  Big fat adult earthworms are also strangely attracted to these radishes!

Big adult earthworms feasting on decomposing tillage radish. From Steve Groff’s Cedar Meadow Farm

What’s Next

We’ll mow-kill this cover crop in late spring when most of it is flowering.  Depending on how our farm plans are working out, we’ll either plant our last cover crop or our final pasture grass mix.  I’ll also be posting on our Fall 2012 soil test results.  I’d like to see if any cover crop benefits show up on soil tests.  Stay tuned!

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5 responses to this post.

  1. Posted by Jim Boak on October 3, 2012 at 11:29 pm

    I commend you on your cover crop program and your determination to turn your soil conditions around.   The tillage radish (so called) is only called “tillage” or “ground hog” to extract more money from the grower. Any of the oil seed radish are quite effective. Yellow blossom and white blossom sweet clover are far stronger than the radish family.   The radish are a member of the brassica family and mycorrhiza fungi can not survive on the radish root system.    Do not be fooled into thinking that the radish family will punch through compaction – they will not.  If they hit a compacted area they will actually push (grow) themselves out of the ground.   Since you have lots of lequme in your mix annual rye grass is a better choice to punch through high density soil but even that has it’s limitations. There is nothing beats iron to shatter a hard pan but then plant a cover crop immediately to get those roots down to hold the soil open and keep density in line.

    I really enjoyed the pictures and your passion.

    Jim Boak National Sales Manager, Salford Farm Machinery Ltd. Mobile – 519.670.1004 Office – 1.866.442.1293 jim@salfordmachine.com Salford Farm Machinery Ltd. – “Solid Performance by Design” Salford Ontario, Canada – Osceola Iowa, USA

    “There is a yield ladder effect when you combine no till with tillage that ratchets ever upward far more rapidly than either practice held alone.”

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    Reply

    • I just saw the link to this post at Solomon’s group and I can’t believe how big your winter cover crop seedlings are after 2.5 weeks. How much rain are you getting now?

      We’re in the high desert, so completely different climate, and we have yet to have success with any cover crop, at least initially. Seems like many seeds sprout a year later. Your post and pictures motivated me and I’ll put some seeds out today.

      Reply

      • Hi Christine, yes these seedlings came up super fast. The radishes and oats were up in 3 days, then everything else followed quickly. We lightly rotovated this plot to kill perennial grasses that weren’t doing so well. While rotovating, we sprayed a microbe mix, seaweed extract, liquid fish, and molasses. I’m wondering if this spray nudged the seeds to sprout quickly. The soil was probably just the right moisture and temp when we planted. We typically get 3″ of rain every month. Do you know why you’re having germination trouble?

      • 3″ of rain is NICE! We finally got some rain too the last few weeks, but just like with you, the clouds went around us all summer.

        One of our problems with germination is that we got pill bugs in the mulch and contrary to some websites, they DO eat seedlings.

        Of course we also got mice and whatever critters and we found that they know a good salad when they see it. Sometimes we’ve planted small seedlings out and within days they disappeared without a trace. Also had mice come in my greenhouse occasionally and there you can see how they pick the nicest seedlings.

        Last year we put some cow pea seeds out in fall and they came up in summer. Wish we got more rain here in fall. I also remember last year I put out cover crop seeds in one area and made sure to water and we did better there.

        Thing is that we never know how cold it will get in winter. 2 years ago down to 4 F and 9 F during two other cold spells. Last winter was very mild and if I’d known, I would have heated the greenhouse the few times it froze in there and we would have kept the tomatoes going through the winter.

        Just transplanted some lettuce, mustard and kale seedlings into our raised beds and found labels for onion and beet seeds from 2 months ago and there’s not a single onion or beet!

        Once leaves are a few inches long, the plants do really well. Still have chard and kale from prior to the cold winter in those beds, attached to the garage. The seedlings I just planted were really small, less than an inch and I’ll be checking every day to see what happens.

  2. Posted by John Weil on January 30, 2013 at 5:16 pm

    The worm picture caption does not accurately describe what is going on there. Those two worms are not eating. They are making love. They each have male and female sex organs and crawl inside each others bands and impregnate each other. They will each lay around ten eggs and each egg will hatch around ten worms. Forage radishes are great! John Weil

    Reply

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