Archive for the ‘soil ecology’ Category

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.

Mow-Killing Rye and Vetch – Will This Stuff Ever Die?

Oh, dear Roundup, you are so enticing!
We planted about 23 acres of a cereal rye and hairy vetch cover crop in September 2011.  It’s now late May 2012, and this stuff is still not dead!  We’re trying to kill it organically by mowing it at the right time (at flowering).  We mowed all 23 acres twice, and the vetch just keeps on coming back!  My go-to cover crop manual, page 71 says vetch does not bear traffic.  Not true, at least for this variety.  The vetch that got ran over by the tractor tires and therefore lay too low to be cut by the bush hog came right back with shock & awe gusto in a few days.  Vetch is a wonderful soil builder and nitrogen producer.  It’s a stellar cover crop, but it’s very aggressive in the spring and livestock don’t like to eat it.  So, we don’t want it producing seed and growing again in our future pastures.

Vetch mat in neighbor’s field. No rye germinated.

Another reason we want to kill it is so we can plant our summer cover crop mixture.   The new seeds need a good start with no vetch competition.  After mowing twice, we shrugged our shoulders and went ahead and planted.  We think the no-till drill (planter) we rented from our county helped with killing the vetch.  The drill has sharp discs that slice the soil surface like a pizza cutter to make a tiny furrow for seed placement.  So far, it looks like the pizza cutter action cut a lot of the vetch at ground level, which is probably what it needed to finally die.  Our bush hog mower won’t go lower than six inches.  We’ll wait and see if the vetch comes roaring back.

Mowing Would’ve Worked Better If…

…If the cereal rye germinated, dang it!  Cereal rye grows strong and tall, up to 6 feet high, and vetch loves to climb it.  Mow-killing vetch and rye is successful when the rye is holding up the vetch.  We know because the rye germinated and grew really well in parts of our 3-acre field.  The bush hog decimated the vetch where it was supported by rye stems, no need to mow a second time.  In our neighbor’s 20 acres, however, virtually no rye germinated, and the vetch just grew in a 3-foot tall dense jungle mat.  The bush hog has a hard time getting under the vetch mat to cut it off close to the ground and kill it good.

Rye Failure

Rye and vetch both grew well in our 3-acre field.

Why didn’t the rye germinate in our neighbor’s 20 acres?  The rye seed could’ve rotted by Hurricane Irene and Tropical Storm Lee’s 15 + inches of rain (vetch is a harder seed than rye).  Another possibility is nitrogen.  I’ve read that legumes will flourish in nitrogen-deficient soil because their symbiotic root bacteria fix nitrogen from the air.  Grasses (rye) are nitrogen hogs and don’t do well when soil N is lacking.  Our 3-acre field had been in pasture for 3 years and had quite a bit of clover.  Perhaps soil N was sufficient there.

Encouraging Signs

I love the sound the bush hog makes when it hits really dense cover crops!  VROOOM!  That means the clippings will make wonderful mulch to armor the soil from weather extremes and entice the beneficial tiny soil animals and microbes to make their homes in our fields.  The fields now feel like a big fat cushion when I walk on them, which is a great feeling and a sign of returning soil health.   The vetch also attracted some birds and insects that I’ve never seen in that high of numbers on our farm before.  The ladybug numbers on the vetch were amazing, and red-winged blackbirds seemed to be very attracted to the vetch as well.  I didn’t find either of these two in our grass pastures, which were right next door to the rye & vetch fields.

Another encouraging sign is nitrogen.  I’m super excited about this, because soil has to be at a decent level of health in order to provide nitrogen to plants naturally.  The soybean farmer that farmed our fields planted annual ryegrass as a cover crop for several winters.  Like vetch, annual ryegrass is notorious for producing lots of seed.  We have lots of volunteer annual ryegrass coming up after we mowed the vetch, and it’s dark, dark green and super healthy looking!  I’ve never seen grasses on our fields look this healthy.  I’m assuming it’s due to the big nitrogen contribution from the beneficial vetch root bacteria (Rhizobium).  Decomposing vetch vines also contribute some N.

What’s Next
Our summer cover crop cocktail is planted.  We expect it to grow really well following all the rye and vetch benefits. We’re planting diverse cover crops to entice a diverse beneficial bug community to our fields to work with biology to pump carbon (organic matter) into the soil.  The healthier the cover crop is, the more likely it will be to provide max benefits to our soil.  We’re excited to see how our new summer cover crop grows.
UPDATE June 1st

Killed vetch in neighbor’s west field. No vetch, but lots of volunteer annual ryegrass! Mowing twice (3 wks and 1 week ago) made vetch residue to break down faster and negated vetch mulch’s weed suppression.

Rich and Jeff mention in the comments about the drill’s discs (they’re called coulters!) do a nice job of cutting and killing vetch.  They’re right and here’s proof!  This first picture shows a green field – I mowed this field twice.  The vetch is gone, but look what’s taken its place – annual ryegrass volunteers!  This must be from past cover crops.  I mowed this field the first time 3 weeks before planting the summer cover crop.  I suppose the time lapse and the second mowing broke down the vetch residue so much that plenty of sunlight got in and encouraged the annual ryegrass to germinate and grow.  This isn’t the end of the world, but it’s not the best situation for the new summer seedlings.

The second pic shows what worked really well for vetch kill and weed suppression:  mow just once, then go ahead and plant using a no-till drill.  The drill’s coulters will finish off the vetch.  The vetch residue turns into a thick crunchy mat.  The new seedlings are coming up through it superbly.  Being not very high in carbon, the vetch mulch will probably not last through the summer, but it will provide good weed suppression while the new plants are getting started.  I’ll definitely use this method of one mow & drill coulter slicing to kill a viney cover crop like vetch again.  Saves time, fuel, and heavy tractor traffic on the field.

Killed vetch in neighbor’s east field. Killed by one mowing and then planting one week later with no-till drill. Drill’s coulters sliced and finished off the vetch.

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