Archive for the ‘soil biology’ Category

Winter Cover Crop Cocktail – January 2013 Update in Pictures

Here’s an update on the winter cocktail we planted in mid-September 2012.  All pictures are from our six-acre east field.  This field was in ailing pasture grasses since fall 2008.  Before we planted the cocktail, we lightly rotovated the grass while spraying beneficial microbes, seaweed extract, fish, and molasses.  Before 2008, this field was farmed in roundup ready soybeans for about a decade.  This is a very old farm field with burned out, very sandy soil.    On the bright side, organic matter has increased by more than 1% (now 2.8%) since 2008.  Based on the success we’ve seen with cover crops in other fields, we decided to super-charge this one with a winter cocktail.

The cocktail:  tillage radishes, oats, cereal rye, Austrian winter peas, hairy vetch, crimson clover, and sweet blue lupine.

Catch Crops:  A Source of Pride and Embarrassment!

All seed varieties germinated really well in September, but the tillage radishes and oats grew extremely fast.  These two catch crops (they catch and hold a lot of nutrients) are designed to grow very quickly in the fall and then winter-kill (die) in very cold temperatures.   Because they catch a lot of nutrients and grow really fast, they loudly display the best and worst parts of field.

Check out these two pictures from late December.  These were in a far corner of the field, where I believe the soybean farmer never planted.  The oats grew to three feet tall, and many radishes reached 3 inches in diameter.  (Big radishes are growing in good soil with plenty of nutrients available for catching.)

Winter cover crop cocktail in best part of field.  Thigh-high oats and radishes dominating other plants with lush, thick foliage.  East field 12.31.2012

Winter cover crop cocktail in best part of field. Thigh-high oats and radishes dominating other plants with lush, thick foliage. East field 12.31.2012

Close-up of lush oats and radishes with under growth of peas, rye, crimson clover.  Some radishes are 3" in diameter.  East field 12.31.2012

Close-up of lush oats and radishes with under growth of peas, rye, crimson clover. Some radishes are 3″ in diameter. East field 12.31.2012

The embarrassing part is captured in this next picture, the poor part of the field.  The oats grew to only one foot tall and started turning red in December.  I believe red leaves indicate phosphorus deficiency, made worse by cold weather.  Most radishes did not reach one inch in diameter.  This is our “you gotta start somewhere” picture.  We know from our previous cover crops that this is typical for our farm, and the next cover crop will do much better because this current cover crop is making big improvements for the soil even though it looks pretty bad!

Winter cocktail in poor part of field.  All plants are small with lots of red leaves.  East field 12.31.2012

Winter cocktail in poor part of field. All plants are small with lots of red leaves. East field 12.31.2012

Winter-Kill:  Change is Good

Our farm got the Arctic blast that much of the eastern U.S. experienced in mid-January 2013.  The oats are now totally dead, and the radishes are dying due to multiple nights with temperatures in the teens.  This is great!  Winter-kill knocks back the domineering oats and radishes, allowing more sunlight for the other cocktail plants as they rush into their late winter/early spring growth cycle.  This is one of the benefits of planting a cocktail – different plants flourish at different times, which extends the growth season.

Winter cover crop cocktail after deep freeze.  Oats (brown leaves) and tillage radishes are dying.  East field 1.26.2013

Winter cover crop cocktail after deep freeze. Oats (brown leaves) and tillage radishes are dying. East field 1.26.2013

Dead oats and radishes with growing cereal rye and austrian winter peas.  East field cover crop cocktail 1.26.2013

Dead oats and radishes with growing cereal rye and austrian winter peas. East field cover crop cocktail 1.26.2013

Winter cover crop cocktail after severe freeze.  Oats and radishes are dead, but peas, vetch, crimson clover and cereal rye are growing and getting ready for spring.  East field 1.26.2013

Winter cover crop cocktail after severe freeze. Oats and radishes are dead, but peas, vetch, crimson clover and cereal rye are growing and getting ready for spring. East field 1.26.2013

What We Hope to See in May 2013

Hopefully this field will be chock-full of tall cereal rye with blooming peas and vetch climbing up the rye.  The crimson clover should be blooming too.  I’m not sure if the lupines survived the Arctic blast, but if they did, I hope they bloom with everything else in May.  It sounds like max prettiness!

We hope all the belowground action is just as dynamite.  It would be great if all the legumes produce nitrogen and all the plants release their signature root exudates to stimulate their preferred part of soil biology.  If all this happens, then this field’s soil health will be well on its way to becoming healthy and productive.

We plan to wait until most of the crop matures so when we mow it, the clippings will be carbon-rich and supply mulch for a long time.   Next up for this field is a primo soil-building summer cover crop.  We’re leaning towards sorghum sudangrass, cowpeas, and buckwheat.  Thanks for reading!

Human Impact and Hope: This Type of Farming is Extraordinarily Good for the Environment

surviving progressI’ve been watching several environmental documentaries on Netflix.  Whatever the focus, every documentary seems to be built upon the theme of “human impact is horrible for the environment – we just can’t help ourselves”.   It’s hard to disagree with this theme when so many U.S. examples are staring at us in the face – the decimation of 75 million-strong herd of Great Plains buffalo, the 1930s Dust Bowl, the Dead Zone in the Gulf of Mexico, the paving of paradises for strip malls, and on an on.  One interviewed gentleman discussed the impact of cities on the environment but said, “Well, people returning to the land isn’t an option either, because that would result in even more land being destroyed.”

A few years ago, I would’ve been nodding my head in complete agreement.  But now, I know there’s another path.  Humans have the resources to provide extraordinary benefits to the environment – healing the land, reversing desertification, and stopping climate change.  I’m not talking about millions of small farms/gardens.  I’m talking about humans using a very low-tech and often vilified tool:  livestock.

Allan Savory, founder of the holistic livestock management framework, has proven that correctly managed herds of livestock can completely heal the land.  It’s all about time management.  The land is pulsed with very high animal impact for a short amount of time and then moved on.   The herd returns months later after the grass has recuperated.  The herd provides another grazing pulse and is again moved on.  Grazing, intense hoof trampling, and manure stimulate grasses to thrive.  Growing grasses extend their roots deeper into the soil profile and take CO2 from the atmosphere and sequester it into the soil.  Plant roots slough off after each grazing pulse, which puts even more carbon into the soil.  High carbon (organic matter) soils hold water and improve the landscape’s water cycle, which attracts more plant and wildlife diversity.  Land on the brink of desertification is restored to beautiful bio-diverse savannah that sustains human communities.  What work is more noble than this?

Check out this short video of Allan Savory explaining the process and proving that it works.  This video is the longer version – very worthwhile watching.

U.S. folks like Greg Judy are using Savory’s principles with management practices called mob-stocking.  This video is very inspirational and demonstrates how land can be amazingly improved via high intensity livestock grazing.  At the end, Greg Judy states that mob stocking can be scaled down all the way to two animals – good news for our small farm.

The housing collapse has delayed our plans for livestock farming for a disappointing several years now.  We’ve been trying to make the best of the delay by cover cropping to improve our farmed-out soil.  The organic matter has increased by 1 to 2 percentage points, and we feel super good about that!  But, we can’t wait to quit our desk jobs and get started with high intensity grazing and watch our soil improve even more.  Thanks for reading!

High intensity grazing improves land.  Herd grazes for short amount of time, then moves.

High intensity grazing improves land. Herd grazes for short amount of time, then moves.

Soil Quality Indicator: Do You Have Mophead Roots?

Check out this picture:

From November 2012 Acres USA article by Hugh Lovel.

From November 2012 Acres USA article by Hugh Lovel.

Have you ever noticed the degree of soil adhesion on your plant roots?  The roots on the right are what we want.  And I know for sure that our pasture roots aren’t there yet.  See the pic at the bottom of this recent post.  It resembles roots on the left. 

Mophead roots mean the plant is photosynthesizing very well and is healthy enough to donate a lot of sugary photosynthesis products to soil microbes via root exudation.  When these sugar goodies start seeping out of roots, soil microbes in the rhizosphere (root area) have a 5-star dinner and start multiplying like crazy.  They make the gums, glues and gels that cause soil adhesion and start delivering minerals and vitamins in plant-friendly form so the plant will get even healthier and make more sugary snacks.  Ain’t it neat?

The roots on the left show a plant that isn’t healthy enough to donate many photosynthesis products to soil microbes.  The plant is probably in survival mode.

Mophead roots are a sign of a fully functioning plant/soil ecosystem.  In our quest to increase our soil’s organic matter, mophead roots are the holy grail!  Those sugary snacks are carbon-containing molecules that get digested through the soil food chain and eventually get turned into stable organic matter.  And well-fed soil microbes will help plants make even more carbonaceous snacks, and in turn, more organic matter. 

 We have some grass that survived rotovating and is growing astoundingly well in our cover crop plots.  I’m going to check the roots this spring to see if they’ve reached mophead status.   Thanks for reading!

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!

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!

Summer Cover Crop Cocktail – Six-Week Update in Pictures

We planted a warm-season cover crop cocktail on 40 acres during the weekend of May 18th.  See our seed chart and details here.  We’re hoping the cocktail will supply all the benefits of typical one- or two-variety cover crops (organic matter production, erosion prevention, nutrient availability) and greatly amplify all these benefits with diversity.  Cocktails planted on other farms have shown that all the plant varieties cooperate and thrive instead of compete.  Many believe this is caused by the plant varieties leaking their signature root exudates into the soil profile to stimulate their desired segment of beneficial soil biology.  With a field’s entire soil biology stimulated like never before, the whole soil/ biology/ plant ecosystem starts cranking!  It’s really neat stuff!  On our three-acre field, which has the best soil quality out of the 40 acres, we’re already seeing these very positive effects including drought resistance, very high quality plants, and low bug and disease pressure.

Let’s start with our neighbor’s east field.  This field was in roundup-ready soybeans for about a decade until fall 2010.  We planted a sorghum-sudan & cowpeas cover crop in spring 2011, rotovated that in with beneficial microbes, then planted a winter rye & vetch cover crop last fall.  We then successfully mow-killed the vetch and planted the summer crop cocktail this May.  Cocktail plant quality doesn’t look as great as our stupendous 3-acre field, but the cocktail is growing despite suffering in the eastern U.S. heat wave.  This field’s soil test results are good, not great.  It is short on calcium and micronutrients like zinc.

Summer cover crop cocktail six weeks after planting. Buckwheat and Dwarf Essex Rape are flowering.

The wide view pic above shows that buckwheat and dwarf essex rape are currently dominating.  These plants are the tallest and are blooming profusely with white and yellow flowers.  It would be ideal to mow these two before they set seed, but I don’t want to cut the other plants in the cocktail.  Mowing plants at flowering ensures most of the nutrients stay in the soil.  When plants make seed, the plant sucks nutrients and sugars from the soil to assist in seed production.  This is a tradeoff that goes along with a highly diverse (20 varieties) cocktail.  On the plus side, these two plants are giving us free seed that will germinate later.

Phacelia in foreground surrounded by brassicas and millets showing heat and drought stress. Neighbor’s east field.

The ferny-looking plant in the middle foreground is phacelia.  Its beautiful purple bloom should pop out any day now.  The brassicas and millets surrounding it are showing some stress from near 100-degree heat for several days and no rain for three weeks.

Our Best Field Shows Cocktail Benefits

Now let’s go to our 3-acre field.  I mentioned in the first paragraph that this is the best field out of the 40 acres.  Its soil test results are good, showing decent nutrients for our very sandy soil.  We took it out of roundup-ready soy production in fall 2008 and planted pasture grasses that failed to thrive for three years.  We rotovated the grass in fall 2011 while spraying beneficial microbes, then planted rye and vetch for the winter.  This spring we mow-killed the rye and vetch and planted the cocktail.  On top of this management, we spread horse manure compost (we go get free horse manure and compost it for about 9 months in static piles).

I’m not sure if the compost explains the health of this field or if it’s the combination of everything we’ve done.  But something is going on!  Some orchard grass survived our rotovating, and it looks night-and-day different from orchard grass in our existing pasture just 20 feet away.  The orchard grass in our pasture is lackluster and starting to go dormant in the drought.  The grass that survived rotovating in the 3-acre field is still dark, dark lush blue-green with no signs of going dormant yet.  Imagine if we had all our pastures filled with grass like this!  It’s some good quality grass for our future livestock.

Healthy sorghum in cover crop cocktail.

Take this above pic of sorghum (looks like corn) surrounded by the other cocktail plants.  The sorghum looks great despite high heat and drought and no nitrogen fertilizer.  This makes me super happy because the soil is clearly providing nitrogen to this nitrogen-hogger of a plant.  Only soil that has reached a decent level of health with a nicely functioning biology community can do this.  The brassicas around this sorghum plant have very large waxy leaves with very little insect pressure.  I can’t get brassicas in my veggie garden to look this good.  Something great is going on in this field!

Sunn hemp and Camelina surrounded by brassicas in cover crop cocktail.

Here’s a pic of sunn hemp and camelina in the center with brassicas all around.  Sunn hemp (left) and camelina (right) look similar at this point, but that will change soon.  Sunn hemp can get giant-tall.  Camelina is an oil seed brassica like dwarf essex rape.  It’s starting to flower, so it will probably stay short.

We’re excited to see what sunn hemp can do in our fields.  It’s a legume, and we inoculated the seed with its preferred Rhizobium bacteria.  This bacteria works with the plant to create huge golf-ball sized nodules on sunn hemp roots.  These Rhizobium nodules fix nitrogen from the air in return for sugary root exudates from the plant.  When sunn hemp dies, the nitrogen will get released into to soil, hopefully just in time for our next winter cover crop’s grasses (oats and rye) to pick it up and use.  This is how cover crops can be a giant nutrient recycling machine that keeps high quantities of necessary nutrients available rather than locked up in the soil.  On top of the nitrogen benefit, sunn hemp can grow up to 10 feet tall!  That’s a lot of nice biomass that holds carbon, nutrients and vitamins.  It will make high quality mulch for the soil after we mow it down.

Big mustard plant in summer cover crop cocktail

Here’s an extra large mustard plant surrounded by millets and blooming buckwheat.

Peredovic sunflower six weeks after planting in cover crop cocktail.

Here’s a sunflower popping up with cowpeas, millets, brassicas and some weeds.  I’m not gonna lie!

Cosmos plant in cover crop cocktail.

I’m very excited to see this cosmos and can’t wait to see its hot pink flowers!  I haven’t seen the other flowers/herbs we planted such as dill, coriander, alyssum.

Big turnip growing well in cover crop cocktail.

To give you an idea of how well the brassicas are growing in this 3-acre field, check out this turnip.  The top of the bulb is already 3 inches wide!  Brassicas stimulate earthworms and other important soil animals and can suck up a lot of nitrogen and phosphorus that was otherwise stuck and unavailable in the soil, so we’re very, very happy the brassicas are growing so well.

Cocktail Failures

Time to take it down a notch and talk about what didn’t work.

Our pasture seeding is a failure.  We planted the same 70 pounds of seed per acre in our existing pastures that we planted in all the other fields, but so far we have just a few wimpy soybeans rising above the grass.  We didn’t expect the cocktail to grow fabulously in our pastures, but we thought many more plants would grow.  Seems our big mistake was not waiting until the pasture grass went dormant.  The cool season grasses were way too competitive with the new seeds in May and June.  We’ll wait to see if more cocktail plants start growing as the cool-season pasture grass starts to poop out in July and August.

Wimpy soybeans coming up in pasture. Pasture seeding didn’t work with cool season grass in May.

Another failure is our neighbor’s west field.  I wrote at the bottom of this post how mowing the vetch twice in this field allowed a lot of sunlight to get through and prompt volunteer annual ryegrass to sprout and grow like crazy.  Well, the annual ryegrass is strongly competitive and has prevented the cocktail from growing.  I should have made sure the annual ryegrass was dead before we planted the cocktail.  We sure are learning our share of expensive lessons!

What’s Next

We’ll let the cocktail grow for another six or seven weeks, then mow it to kill in mid to late August.  Then we’ll come in and no-till drill (plant) a cocktail for winter.  Many of the summer plants will survive mowing and won’t die until the first hard frost, which happens around Halloween here.  We have some experience with this with sorghum-sudan going into rye and vetch.  We’ll see how it turns out transitioning with cocktails.

We hope come mow-time in August that most of the plants are flowering or starting to make seed.  Plants at this stage are easy to mow-kill.  In the meantime, we’re very happy we experimented and planted this cocktail.  Each plant variety is doing its own little thing in the fields such as stimulating soil biology, manufacturing carbon for the soil, and harvesting minerals that will be very available for subsequent plants to use and thrive.  It’s way cool to use plants that will go to work for us and contribute all these benefits for improved soil health!

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.

Top Five Pros and Cons for Rye & Vetch Cover Crop in Veggie Gardens

Cereal rye and hairy vetch cover crop. Five feet tall 4/20/12

Not too long ago I was one of those people who knew a lot about plants but very little about soil.  I’d leave my veggie beds bare for the winter, not knowing what that meant.  After learning about soil’s needs, I started planting cover crops in 2011, and I’m so glad I did!

In late summer and fall of 2011, I planted cereal rye, a cool-season grass that makes rye grain, and vetch, a viney legume, in all of my veggie beds.  I inoculated the vetch seed with the nitrogen-fixing Rhizobium bacteria and then inoculated both with mycorrhizae.  Now it’s late April 2012, and it’s still alive and growing like crazy!

Here’s what I learned:

#1 Rye and Vetch Change Soil Drastically (PRO)

When I dug out bermuda grass (and a lot of trash) to make my veggie beds, the soil was dry, hard, and dusty.  I knew it would take a long time to reach the desired chocolate cake consistency – dark, moist, spongy, and smelling good and earthy.  With the rye and vetch cover crop, it’s almost there, and a huge difference from last summer!  The soil underneath the cover crop is very soft and spongy with beautiful aggregates.  This good structure will allow veggie roots to grow rapidly and air and water to percolate down into the root zone.

A great gardening goal is to always have something green and growing.  No bare soil!  Plants feed beneficial microbial soil life through root exudates.  As this cover crop was growing, it leaked a lot of sugary carbon compounds out of its roots to attract and feed microbes.  These bugs made the gums, glues, and gells that form soil into that chocolate cake consistency.  Bare soil has no living roots to maintain beneficial microbes at high populations through the winter.  Keeping soil life alive during the winter improves soil and ensures it’s ready to help veggie plants thrive in the spring.

#2 Plant-Available Nitrogen (PRO)

Nodules: Rhizobium bacteria fixing nitrogen on vetch roots. From http://ryansgarden.com

Instead of using synthetic nitrogen or expensive organic nitrogen inputs, why not grow vetch?  If inoculated with Rhizobium bacteria, the Rhizobium will fix nitrogen from the air and put it into nodules on vetch roots.  Isn’t that the coolest thing?  This handy cover crop reference says,

“Few legumes match hairy vetch for spring residue production or nitrogen contribution.  […] Hairy vetch delivers heavy contributions of mineralized N (readily available for the following cash crop).  It can provide sufficient N for many vegetable crops, partially replace N fertilizer for corn or cotton and increase cash crop efficiency for higher yield.”

That’s a whole lot of nitrogen!  And it comes at low expense with many other benefits.

#3 Weed Suppression and Free Straw Mulch (PRO)

Rye and vetch mulch drying down after cutting

No weeds here!  The cover crop’s outrageous growth in early spring smothers weeds by completely blocking sunlight.  I’m aiming for mostly no-till, so I’m cutting the rye and vetch off at its base.  This is generating a boatload of mulch!  Vetch mulch has a high nitrogen to carbon ratio, so it will decompose readily.  But rye straw at this late stage of growth (flowering seed head) has a lot of carbon, so it should last well into late summer.  This thick mulch will protect soil, keep soil temps cool in the summer so biology can thrive, hold in moisture, and prevent dirt splatter onto veggie plants.  And it’s free and organic!

#4 Beneficial Predators (PRO)

I’ve noticed a very big and diverse above-ground soil life community in the rye and vetch.  Loads of tiny mites, beetles, crickets, spiders, and ladybugs.  The diversity and populations are larger than I’ve ever seen in my garden.  The handy cover crop guide cited a study that showed a rye/hairy vetch mix sustained a population of aphid-eating predators that was six times that of unmowed volunteer weeds and 87 times that of mown grass and weeds.  I’ll take it!  Let’s get our predator populations really going and save ourselves loads of time this summer killing harmful bugs!

#5 Bad Timing for Early Veggies (CON)

Flowering cereal rye can be mow-killed.

Rye and vetch can be killed any time with herbicides, but organic gardeners must be patient.  Vetch can be killed organically when it flowers (late April/ early May in East Coast zone 7).  Cereal rye can be killed organically when it flowers around the same time.  (Flowering grain means the seed head is developing and the little stamens (anthers?) start to come out and drop pollen.)  Rye and vetch will die at this time by mowing or just knocking it down flat at its base.  No herbicides.

But you want to plant peas and lettuce and radishes in early March?  Whoops!  Not gonna happen unless you till in the cover crop or use herbicides, both of which I don’t want to do.  You can keep cutting it down at ground level, plant your peas, and then keep cutting the rye back, but rye REALLY wants to live at this stage and will stunt your early crops.  I tried it.  I did not try acetic acid sprays, which is another option.

This situation requires better planning in the fall.  I’ll need to designate beds for early spring veggies, and plant winter cover crops that will winter-kill (die on their own from hard freezes), such as oats and radishes.  But for later-planted summer crops like tomatoes and peppers, I’ll definitely plant rye and vetch again.

Seed Sources

If you don’t have a local source, search online for “rye and vetch seed for sale.”  High Mowing Seeds sells five pound batches for about $20, plenty for a 1,000 sq. ft. garden.  Think of all these benefits for such a low cost!  Thanks for reading!

Acids and Exudates: Plant Diversity Improves Soil

The more I learn about farming, the more I realize that plants are truly wondrous living things.  It’s easy to think plants are boring and passive.  After all, they just sit there.  But here’s some news!  Plants are powerful chemists and VERY active participators in their environment.  For our farm, we now see plant properties and behaviors as a tool for rejuvenating our dead soil.  This post explains what we’ve learned so far and how we plan to implement our new plant knowledge.

 Plants Leak Yummy Exudates

At the 2011 Acres USA conference, we learned a lot about what plants do below ground.  We learned that plants make a lot of sugars and other compounds from photosynthesis, and instead of using them all for energy, they leak a lot of them from their roots to attract and stimulate soil microbes.  These compounds are called “root exudates”.  

Plant root exudates. "Signaling molucules" that stimulate beneficial bacteria and fungi. From Marschner, 1995. http://edu.griggbrothers.com/TechnicalBulletins/TB2008b_printer.shtml

We learned even more about root exudates from Jill Clapperton.  She said that every plant variety leaks its own signature of chemicals in the form of amino acids, carbon, and organic acids to attract the beneficial soil microbes it needs to live and thrive.  She said that plants modify their environment and build their own microbial community in the soil.  Plants MODIFY their environment and build their own community?  This was news to us, and we thought it was really cool! 

She went on to say that plants leak a LOT of chemicals.  These chemical compounds are signs of welcome and warning.  Most of the compounds are welcome chemicals that attract a very beneficial and helpful bacteria and fungi community that like the plant and promote its growth.  Plants also leak warning compounds to keep themselves safe from soil herbivores and other threats. 

Exudates Can Improve Soil

Then Clapperton started talking about how farmers and gardeners can take advantage of plant properties to improve soil and grow food that’s very nutritious.  She encouraged the audience to fill the soil profile with different plants that have shallow, medium, and deep roots.  Filling the soil with many diverse plant roots will take advantage of the fact that all plants leak different compounds that will stimulate different segments of soil’s beneficial biology. 

Our soil has a long way to go before it is truly fertile with a fully restored biology.  We need a diverse soil biology community, so we were very interested in what she said about advantages of different plant categories:

  • Cowpeas (black-eyed peas), one of the best legumes for building soil.

    LEGUMES such as peas, beans, clover, and alfalfa leak exudates that attract both Rhizobium bacteria and mycorrhizae fungi.  Both of these are huge plant growth promoters.  Rhizobium fixes nitrogen from the air in return for sugary exudates.  Mycorrhizae are amazing symbiotic fungi that work wonders for the soil.  They go for maximum carbon exudates from the plant.  To get what they want, they boost the plant’s photosynthesis by conferring drought resistance and bringing phosphorus, copper, zinc, manganese and other ions and amino acids to the plant.  By making the plant healthier, they get even more carbonaceous exudates from their host.  Mycorrhizae turn a lot of it into glomalin, a significant carbon component in the soil that helps glue soil particles together and form wonderful aggregates that let more air and water percolate through the soil.  Legumes are clearly a win-win-win for soil.

    Sorghum, a warm season grass

  • CORN and WARM-SEASON GRASSES and Broadleaves such as SUNFLOWERS leak massive amounts of exudates.  They are trying to attract a large, diverse microbe community for protection and growth promotion, including lots of mycorrhizae (myco).  So this plant category can also stimulate lots of soil biology and sequester quite a bit of carbon via myco.
  • BRASSICAS such as mustards, radishes, broccoli, kale, etc. are different.  They do not associate with

    Mustard, a great brassica for improving soil.

    myco.  Instead, they leak some rather harsh acids.  They don’t need myco to go get soil minerals because they can use acids to get it for themselves.  Brassicas’ acid exudates can cleave off calcium that is tightly bound to phosphorus in the soil.  The brassica plant then soaks the phosphorus right up.  That’s why planting brassicas is a good method for “mineralizing” tightly bound phosphorus and making it available for the next plants that grow as the brassica decomposes.  Brassicas also stimulate the middle of the soil food web, arguably the most important part – the mites, earthworms, and other recyclers that prey on bacteria and fungi to keep them in a healthy balance.  Clapperton said she found through multiple studies that for some reason, brassicas make earthworms and other soil animals go really nuts in a good way.  So brassicas are key for mineralizing hard to get soil minerals and for stimulating the very important soil animals.

    Alfalfa

  • DEEP ROOTERS such as ALFALFA and SWEET CLOVER can bring up fertilizers from long ago that have leached deep into the soil profile.  The long roots also make channels for earthworms and other beneficial biology to travel.  The channels provide for better air and water percolation which fights compaction and improves soil structure.
  • POLLINATORS like PHACELIA and other FLOWERS have nice, fine roots with lots of fungi.  As pollinators, they can attract more above-ground diversity to our farm.

Our Plan

We probably won’t get livestock this year, so we’re going to take advantage of our prolonged delay to improve the soil by growing a big cover crop cocktail.  We’ve ordered the seed mix that includes several varieties from each category mentioned above. 

 

Phacelia tanacetifolia, a native pollinator that also helps rejuvenate soil. And it's pretty!

Our neighbor’s 20 acres has a rye and vetch cover crop growing like crazy right now.  We’ll mow when it flowers to kill it, then drill (plant) the cover crop seed.  Our own 20 acres are in perennial grasses (planted fall 2008).  We’ll lightly rotovate them to kill, then drill in the cover crop. 

We’re really excited to see how the cocktail grows.  With the big diversity of plants and flowers, I’m hoping it will be super pretty.  As late summer nears, we hope to see more wildlife and insects and good water retention.  And as all the different plants stimulate all parts of soil life, we should see our subsequent crops growing much better.  Thanks for reading!

Save the Microarthropods! Rethinking Tillage and Rotovating

We’ve gone from tillage-happy to tillage-doubtful.  We learned some things about tillage at the December 2011 Acres USA conference that really resonated with us, so we’re reconsidering our plowing down cover crop strategy in order to nurture a key part of the soil food web…

Rotovating in late August 2011

Up to now, our strategy for improving our sandy soil’s fertility involved growing massive cover crops to maturity and then plowing them down every spring and fall.  The “plowing down” involved using our rotovator (a very wide garden tiller) to incorporate most of the plant tissue into the topsoil so it could stimulate soil biology and eventually break down into organic matter.  At the Acres conference, we got confirmation from several speakers that this was the best method for improving soil’s biological fertility, especially if the plants are mature and lignified (more brown than green).  It felt great to hear this because it fit exactly with our plan!  Then we heard Jill Clapperton speak.  She was the rhizosphere ecologist for Canada’s agriculture department, and her research really compelled us to reconsider tilling so often.  Here’s why:

Lots of Tillage Hurts the Soil Animals in Middle of Food Web

Soil Food Web

The bottom of a very simplified version of the soil food web starts with bacteria and fungi, which are the primary digesters.  The middle group is the small animals, and they eat everything!  They prey on each other, bacteria and fungi, and plant residue.  This group consists of microarthropods (mites), earthworms, nematodes, enchytraeids, and some protozoa.  The top of the simplified food web is the larger animals that live on the soil surface like springtails, beetles, and even mammals like field mice.

Clapperton talked about long-term research results that showed some of the small animals in the middle of the food web disappearing after five years of tillage.  She said most of the small animals, especially the microarthropods, make their homes in the top few inches of the soil, and when tillage repeatedly destroys their infrastructure, the animals just leave.  The microarthropods cannot live in such an unstable environment.

Plants pick up and assimilate nutrients that have gone through soil’s biological system much better than nutrients from fertilizer.  For this reason, it behooves us as farmers with the goal of growing top quality grass to nurture the soil’s biology as much as we can.  We’d love to have the microarthropods on our farm just because they’re pretty amazing animals, but more than that, they are a very essential part of a vibrant soil food web.

Microarthropods are Voracious Predators

Macromite's Blog selection of soil mites, springtails, and Parajapyx. http://macromite.wordpress.com/2009/04/29/a-menagerie-of-microarthropods/

The animals in the middle of the food web are soil’s predators and recyclers.  This video shows two soil mites battling over a juicy springtail.  If we saw large, familiar animals trying to rip apart another animal like this on a regular basis, we’d probably have a whole different view of nature!  But violent predation like this happens all the time in the soil, and the soil’s health, and therefore the nutritious quality of our food, depends on it.  Here’s how:

The microarthropods chew up bacteria and fungi, poop them out, and regenerate the whole food web cycle in a very positive way around plant roots.  Without the good, natural predation check, the bacteria and fungi proliferate too much and start competing with plants for nutrients that plants need to grow and thrive.  Soil bacteria and fungi will beat out plants every time for nutrients if they’re allowed to do so.  Therefore, predators like microarthropods are essential for healthy, vibrant plants.

Microarthropods Stimulate the Soil Food Web

The microarthropods also help out bacterial and fungi.  They eat everything, including each other and larger pieces of plant residue.  Everything they eat is pooped out in new, much smaller particle sizes that are now accessible to bacteria and fungi for food.  This stimulates the bacteria and fungi to multiply at a good rate, in turn feeding the whole system.

Tiny Oribatid mite: Synchthonius crenulatus (Jacot) on a Times-Roman 12 pt Period. At http://macromite.wordpress.com/2009/07/01/full-stop-on-canada-day/

So, the middle of the food web is essential to healthy soil and therefore, high quality grass.  If repeated tillage makes them go away, we’re going to stop.

Our New Plan

Instead of rotovating our cover crops into the soil every spring and fall, we’re going to instead mow at the right time to kill them.  Clapperton advocates mowing because the clippings act as a good armor for the soil, and they insulate the soil from temperature extremes.  This helps the soil food web stay active during the hottest, driest times of the year.  She also said plant roots are soil’s most available form of organic matter.  Roots leak carbon and nitrogen compounds constantly to stimulate beneficial bacteria and fungi.  When the plant dies, the roots decompose into organic matter, and the tunnels left behind are great for air/water infiltration and for providing movement channels for earthworms and other animals.  Another disadvantage of tillage is that it collapses a lot of these tunnels.

We’re not going to sell our rotovator.  We’ll use it this spring to rough up our 20 acres of perennial pasture so we can give our new cover crop cocktail a good chance to grow.  We’ll rotovate very lightly and probably leave a lot of the grass standing.  We’ll then plant successions of cover crops, and then plant our final perennial pasture mix for grazing.  We might not ever need to rotovate our fields again, unless we want to kill the perennials again to do some crop rotation, or we detect soil compaction problems (unlikely in our very sandy soil, with the help of cover crops).

We hope that our new plan will help our soil thrive.  Giving up repeated tillage will hopefully give our farm a very healthy, complete soil ecology that includes the very necessary predators and recyclers and will also help maintain good soil structure with intact earthworm channels.

Most of the info in this post came from Jill Clapperton’s two presentations at Acres.  Audios of her presentations are available here.

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