What Extreme Drought? Our Cover Crop Cocktail Didn’t Notice

What a tough summer!  Our farm experienced the 2012 extreme heat and drought that broiled most U.S. farmland this summer.  Nearby farms received okay amounts of rain, but several good rainstorms split and went around us on all sides this summer.  Up until the fabulous 3 inches of rain we received last weekend, about 1.5 inches fell on our farm from June to August, and we’re used to getting 2 to 4 inches every month.  Needless to say, our cool season grass pastures went completely dormant.  The grass was ugly brown and very crunchy.

Drought-Resistant Cocktail

On the other hand, our summer cover crop cocktail did quite well!  We got some good education by watching the cocktail respond to the heat and drought.  The drought did decrease biomass production – the sorghum and millets stopped growing and never got taller than hip high – but foliage maintained a good enough green color even during the strings of 100-degree temperature days.  We will definitely plant diverse mixtures of brassicas, legumes, and warm season grasses for summer grazing for our future livestock.  It’s drought insurance!  And the mixture seemed to work together to survive the drought.

Ranking Best Plant Varieties

In order of best drought resistance, here are the plant varieties that did well on our farm this summer:  Mustard; turnips; sunn hemp; sorghum; soybeans; cowpeas; millets; sunflowers.  I didn’t include dwarf essex rape and buckwheat because they were already mature and setting seed when the drought hit.  Alfalfa and yellow sweet clover remained small, but will probably grow well this fall – I believe this fits their normal life cycle.  Phacelia did not seem to survive the drought.  I did see some safflower that looked good.  I didn’t see any hairy indigo, but I might be mistaking it for a weed.  We do have our fair share of summer weeds!

Late August summer cover crop cocktail after mowing in late July.

This pic shows the cocktail a few days after our recent 3” rain soaker.   The cocktail is now about 18” tall.  We mowed it in late July due to marestail weed pressure. Mowing seemed to stimulate the cocktail.  Mustard, turnips, sunn hemp, sorghum, cowpeas, and millets all started re-growing, even at the height of the drought.  Everything greened up really nicely after the rain, but the mustard and turnips have some stinkbug visitors.  They are getting de-juiced by harlequin bugs.   This shows our soil still has a ways to go before it can support complete plant health.

Cocktail Evaluation

Overall, we’re really glad we planted the cocktail.  Based on cocktail plant density and diversity and healthy green growth during extreme drought, we believe the cocktail provided many more soil health benefits than our existing grass pastures.   Our grass went completely dormant, and dormant grass doesn’t sequester carbon and feed soil life like green growing plants do.  Admittedly, we are lacking the very beneficial animal impact, so our grass would have done better if we had a nice rotational grazing herd.

Even during the drought, the cocktail sucked up and held onto soil minerals that will fertilize future plants, produced biomass that will become nice mulch this winter, and sequestered sugary carbon compounds as it stimulated and fed the soil life below ground.  Also, the cocktail’s legumes produced nitrogen that will be released for subsequent crops, as shown by this picture of our sunn hemp root nodules.

Nitrogen-producing nodules on sunn hemp roots.

What’s Next

We’re getting ready to plant a winter cocktail in early September.  It will be a mix of oats, cereal rye, Austrian winter peas, sweet blue lupin, and tillage radish.  We’ve decided to rotovate an additional five acres of our grass pastures, and will plant the cocktail there too, with additional varieties of vetch and turnips.  We hope that the cocktails will continue to keep soil minerals available to plants, increase organic matter, and stimulate soil life, so when we are able to quit our full time desk jobs we’ll have some amazingly fertile soil that will grow fantastic forage for our livestock.    Thanks for reading!

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2 responses to this post.

  1. Posted by Paddy on September 18, 2012 at 5:57 am

    Hi Kelly, enjoyed reading about your summer cover crop journey. I ranch cattle on 600 acres in south eastern new south wales, Australia. Our dominant summer perennial grass is kikuyu. Winter is clover and rye. Traditionally I grow winter feed. Usually triticale and rape. . Last year I planted my first cocktail cover crop in a sick 50 acre paddock obviously exhausted by the years of cereal growth. Didn’t use fertilizers Great result. ( my neighbours think i must be smoking something that is mind altering) Last week I drilled into 3 experimental pastures. 10 acres, 5 acres and 12 acres. Buckwheat, chicory, white clover, arrow leaf clover. I threw in some winter seed I had, oats and annual rye grass. I seeded about 35lbs per acre. I note you had poor results drilling into your perennial grasses. We are just over the frost, so hopefully my perennial are still dormant. Ours Is a cool climate. Here’s hoping!! Paddy

    Reply

  2. Thanks for commenting Paddy! Yes, I think grass dormancy is key. We have patches of bermuda grass here and there. It was still dormant when we drilled the cover crop seed. The cover crop came up in the bermuda and did quite well. The cover crop plants that did come up in our non-dormant cool season grass didn’t survive our summer drought, but after the rains came back, lots of sorghum seed germinated and grew. It’s now about 3 feet tall. It looks pretty sickly (nitrogen starved), but i thought it was interesting how they waited for the best moment to germinate. Good luck with your pasture seeding!

    Reply

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