Archive for the ‘cowpeas’ Category

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.

Cost of Cereal Rye and Vetch Cover Crop

Even though our winter cover crop of rye and vetch did not germinate well, I figured I’d go ahead and lay out its cost so we could compare it with the cost of our summer cover crop of sorghum sudan and cowpeas.  Below is the cost for drilling rye and vetch seed into about 22 acres of our neighbor’s fields (where we grew sorghum sudan and cowpeas) plus about 3 acres of our own former grass pasture.  We bought enough seed for 27 acres just in case we ran out.  We planted on Labor Day weekend 2011.    

Seeding rate:  Rye at 40 lbs per acre; Vetch at 20 lbs per acre. 

Seed Cost = $1,284.  (20 – 55 lb. bags of rye at $17.30 per bag, 11 – 50 lb. bags of vetch at $83 per bag, vetch inoculant = $25)

Mycorrhizal Inoculant = $388 (11 lbs)

Drill Rental = $200

Diesel = $22 (~ 5 gallons)

Labor = $160 (8 hours at $20 per hour)

Total = $2,054 or about $82 per acre (25 acres total) Sorghum sudan & cowpeas cost $70 per acre, but did not have mycorrhizal inoculant.

New Seed Supplier

Myco inoculant (top), vetch inoculant (right), cereal rye seed (bottom), vetch seed (left)

We bought the seed from Sam Swarey, a seed rep for Pennsylvania-based King’s Agri Seeds.  Mr. Swarey is Amish and lives close to us.  We’re glad we found a knowledgeable seed salesman that can supply us with just about any seed we’d like.  King’s Agri Seeds is focused on grazing and cover crops, which fits us well.  Even though we can’t pick up the phone and call Mr. Swarey, we’re glad we found him and his fantastic customer service.   

Vetch’s Low Price

The vetch seed cost would have been much more expensive, closer to $200 per bag, but Mr. Swarey had bags of last year’s vetch left over and sold them to us at cost.  Yay!

Vetch Inoculant

This inoculant is bacteria that forms nodules on vetch roots and fixes nitrogen from the air.  When the vetch dies (we’ll kill it next spring), the nitrogen will be released into the soil and made available for the next crop.  Very healthy soil might already have the bacteria, but since our soil is so lacking in organic matter and soil life, we thought it was wise to spend $25 and coat the seeds with it.

Mycorrhizal Fungi Inoculant

We bought this from AgVerra and mixed it with the seeds with a little milk before filling the seed drill.  Mycorrhizal fungi are amazing creatures.  They colonize plant roots and make the area around the roots acidic so nutrients like phosphorus, calcium, magnesium, zinc, etc will be attracted to the roots and will enter the plant for nourishment.  Cool, huh?  The fungi have a mutually beneficial relationship with plants because they help feed plants minerals, and the plants feed the fungi goodies made during photosysthesis.  These fungi are also responsible for making a soil component called glomalin.  As the fungi die, the glomalin is sloughed off into the soil.  We want more glomalin in our soil because it’s 40% carbon, and it gives the soil nice fluff and keeps stored soil carbon from escaping.  It’s tough stuff, and it’s exactly what our soil needs.  We decided to spend the money to repopulate our fields with these very beneficial fungi.  This should be a one-time cost.

Cost Comparison with Sorghum Sudan & Cowpeas

The Rye and Vetch cost was over $80 per acre, and the sorghum sudan and cowpeas cost was around $70 per acre.  The sorghum & cowpeas did not include the mycorrhizal inoculant, but we got a very good deal on the vetch price. With our poor rye and vetch germination, we estimate that half the seed did not germinate.  So, about $1,000 of this cover crop price was spent in vain.  We believe the cause of poor germination was the combination of planting into very fluffy soil right before a tropical storm dumped 10 inches of rain.  We learned our “grand” lesson and  for sure won’t make these mistakes again!

Learning How to Rotovate a Green Manure Cover Crop

In mid-August we rotovated (shallow-tilled) our sorghum sudangrass and cowpea cover crop.  This post will describe the learning curve we encountered with our first time rotovating and how we got it to work.

Good mix of brown and green plant material

We planted this cover crop at the end of April, let it grow to about 5 feet tall, and mowed it in July.  Our bush hog made a lot of nice mulch.  After a week or so, the sorghum sudan and cowpeas came charging back mean and green and grew about 18 inches.  This is exactly what we wanted.  We wanted to rotovate green plant material “green manure” to feed and jumpstart soil life, and brown mulch material to breakdown and transform into organic matter.  These fields (our neighbor’s) were previously planted in no-till roundup-ready soybeans for at least a decade.  Organic matter is very low, below 2%.  Our goal is to stimulate all the soil critters to grow and multiply and bring life back to the fields.

our 7-foot rotovator

Rotovators are tillage tools, like a very wide garden tiller.  Our rotovator is 7 feet wide.  It has no wheels.  Instead, it skids along the ground like a sleigh, and the tractor’s 3-point hitch keeps it level.  We rotovated 25 acres of sorghum sudan and cowpeas (our neighbor’s fields) and two acres of our own grass fields.  In addition to the rotovator, our tractor was carrying a homemade spray tank on the front.  The spray tank is described here, and the spray mix (beneficial soil microbes and other goodies) is described here.

Why Rotovate?

We want to decrease the time it takes for the fields to get healthy.  Our own fields, which were previously under the same soybean farmer, have been in pasture grass for the past 3 years.  We’ve been mowing 2 or 3 times per year, fertilizing, and applying compost.  Unfortunately, we’ve seen very little improvement in the grass.   After studying biological farming techniques, we’re convinced the soil needs some disturbance to break up the sandy, crusty topsoil and to get a good dose of plant material and biology into the root zone.

Incorporating a green manure crop is essentially chopping plants and feeding them to the soil.  Five percent of a plant’s makeup comes from the soil (ash/minerals), and the remaining 95% comes “free” from photosynthesis of sunlight, water and air.  Incorporating the minerals (now in plant form) and all the free stuff like carbon, vitamins, and plant metabolites, provides a huge benefit to the soil in terms of improved soil structure and energized soil life.  We’re aiming for “chocolate cake” soil:  very dark, loose, and crumbly with high organic matter and a very healthy soil ecology.

Starting Out

Our goal was to rotovate as fast as possible (to decrease time in the tractor) and still be satisfied with the results.  In terms of results, we wanted to see most of the mulch incorporated into the top 4 inches of soil with a good mulch cover left on the surface for protection.  We also wanted to see a relatively smooth seedbed, but not so smooth that our sandy soil was pulverized.

We quickly discovered that getting our desired results would take a lot of trial and error!  On top of taking a large amount of time, rotovating includes many variables:  tractor speed, rpm, soil moisture, rotovator blade depth, vegetation content, row coverage (overlapping), and the position of the rotovator’s back gate.

Rotovating too slowly- powdery soil with little surface mulch

Lesson #1:  Don’t go too slowly.  On the first day, we started rotovating in our tractor’s 2nd lowest gear at about 1900 rpm.  (The rotovator manual said 1900 was the max).  This is moving VERY slowly, about 2 mph.  2nd gear cut the plants off at ground level but left them all on the soil surface.  The blades seemed to be bouncing a little instead of digging down.  Then we tried 1st gear at 1900 rpm.  Going slower allowed the blades to get into the soil, but the rotovator now chopped the soil way too much and turned it into powder.  All of the vegetation was incorporated with hardly any protective mulch on top.  It was getting dark, and we hadn’t even finished two acres.  We decided to sleep on it and try again tomorrow.  That night, it started raining heavily.  I had nightmares recalling the old 1930s TVA movie clips showing drastic soil erosion!  I didn’t feel good about the soil turning to powder.  It felt like a giant step back, and I was worried.

Pile made by rotovator catching mulch from previous row and dragging it.

The next morning, we walked out to look at the fields.  No erosion at all, everything was fine.  Except now in the morning light, we could see all the big piles of soil and mulch the rotovator created.  One side of the rotovator kept catching on the mulch in the previous row and dragging it until it balled up big enough to discharge out the side.  It was discouraging because we didn’t want to bring our tractor back over those nice and fluffy rows to smooth out the piles.  The tractor is heavy and would compact the soil and remove all the air that microbes need when they’re working.  Looked like we’d be pitch forking them by hand!  (We did.)

Lesson #2:  Don’t rotovate bone-dry soil.  We waited a few days for the rains to stop and the soil to dry out.  We knew 1st gear was bad, so we tried 2nd gear again at a little lower rpm, 1800, and we also set the blade depth deeper.  Voila!  It worked!  Most of the mulch was getting incorporated with some left on top.  But the major lesson here was soil moisture.  After the rain, the moisture level was now just right.  The soil’s aggregates stayed together in nice, small clumps.  It was too dry on the first day, and that’s why it got pulverized so easily.

Uneven seedbed from rotovating in 3rd gear with gate up

Lesson #3:  Leave the back gate down if you need a smooth seedbed.  We were still making the big piles though, and we couldn’t figure it out.  We decided to go faster, in 3rd gear, and lift the rotovator’s back gate up so all the mulch could leave without balling up.  This just helped make the piles a little smaller.  Also, keeping the back gate up left the soil surface very uneven.  That was another concern because we didn’t know how the drill (planter) would perform in a seedbed that bumpy.  We put the gate back down.

Lesson #4:  Don’t overlap rows.  It wasn’t too much longer when we discovered what was making the big piles.  I was bringing an iced tea out to my hubby in the tractor.  When he saw me to his far left, he turned his head and waved.  I saw the tractor and rotovator steer to the left far into the previously rotovated row, and a giant pile came out the side!  From then on, we concentrated hard on keeping the rotovator squarely on unrotovated ground.  This was hard to do continuously, but it worked!  We ended up leaving very narrow strips of the cover crop standing just so we’d avoid the piles.  This didn’t look very good, but we’re fine with it because the sorghum sudangrass and cowpeas will both die at frost.

Just right - moist soil, most of plant incorporated with plenty of protective mulch left on top

Lesson #5:  Do lots of test runs on the day you’re rotovating.  We ended up going back down to 2nd gear at 1800 rpm for most of the job.  The cover crop was very lush and thick in some places, and we needed a slower speed for most of it to get incorporated.  However, when we rotovated our 2 acres of pasture grass, we could go back up to 3rd gear.  The density of the vegetation makes a difference.

With all the variables involved, it’s key to test before you start to find the happy medium for that day.  Make sure your soil has some moisture (but not anywhere near wet) and start testing to see what speed and rpm gets most of the plant material below the surface and still leaves a protective mulch cover on top.   And if you start creating big piles, stop overlapping the rows!

Hurricane Irene Side Note:  Irene came two weeks later with 85 mph winds and 10 inches of rain.  The next morning, there was surprisingly little water standing and no sign of erosion.  The large quantity of mulch, both below and above the surface, protected the soil well.

Adding Biology to Our Soil with AgVerra and Tainio Products

Tractor with 3-point hitch rotovator and front-mounted spray tank on forklift attachment

We sprayed biology (beneficial microbes), enzymes, microbe stimulants, and molasses onto our sorghum sudangrass and cowpeas cover crop just before we rotovated it into the soil.  Our rotovating is described here, and our home made spray tank and molasses adventure is described here.  Our soil has very low organic matter and is lacking in earthworms and other signs of soil life.  Because we were already going to the trouble of rotovating, we applied beneficial biology while we were at it.  Our goals are to help the cover crop residue break down quickly so we could plant our winter cover crop soon and also to get good microbes into the soil so the soil can start coming back to life and creating organic matter.

Good residue breakdown with Tainio products in topsoil. 3 weeks after rotovating. Neighbor's east field - 1.9% organic matter, 6.6 pH, 5.6 CEC

We attended a fantastic farm meeting at Keystone Bio Ag near Lancaster, PA this summer.  They were selling many Tainio products, and we purchased Spectrum, a mix of beneficial microbes and Pepzyme Clear, an enzyme product that stimulates microbe reproduction.  The cost for enough to cover 10 acres was $240.   We were also in contact with AgVerra, a company I found through Acres USA.  They offered to include us as one of their project farms.  In return for feedback on their products, we got 50% off.  Whatta deal!  They sent us 20 acres worth of their Stubble Digester product, a mix of microbes that are especially good at breaking down plant residue quickly, and PTM,  a mix of beneficial soil microbes plus goodies like kelp extract, fulvic acid, and plant growth regulators.  The cost for 20 acres worth was $280 (half off) or $14 per acre.

Besides having a hard time keeping our farm cat away from the Spectrum because it smelled like fishy cat food and also curbing my hunger because the Stubble Digester reminded me of crushed oreos, all products were very easy to work with and get into the spray tank.  All products dissolved really well in the tank.

The AgVerra products offered better visibility coming out of the spray tank.  Their Stubble Digester and PTM are jet-black in color and ended up giving the spray mix a slight oily (not greasy) consistency.  This allowed us to see the spray mix cling to the leaves.  It reminded us of vinaigrette dressing!   This is not a huge benefit, but as newbie farmers, it felt good to actually see the product landing where we wanted it, and it helped us verify that our spray tank was working.

We did not speak directly to the Tainio company, but Keystone Bio Ag had good customer service and pointers in using the products.  AgVerra also had excellent customer service – they have nice product information online, and Alfred went above and beyond to help with product selection, suggestions on our home made spray tank, etc.

Good breakdown with AgVerra products, 2.5 weeks after rotovating. Neighbor's west field - 1.5% organic matter, 5.9 pH, 5.0 CEC

We started first with the Tainio products on our neighbor’s east field, which is their best field in terms of soil tilth, organic matter and mineral content.  The soil in this field is much easier to shovel than their other fields.  AgVerra’s products went on our neighbor’s remaining lower-quality fields and on the 2-acre slice of our pasture.  We took these pictures this morning, 2.5 to 3 weeks after rotovating and 6 days after Hurricane Irene’s 10 inches of rain.  Both products seem to be working really well.  The residue has broken down so nicely that we could plant our winter cover crop now, except the soil is too wet for heavy equipment.

I’m excited to see what our winter cover crop looks like this fall and next spring.  Maybe I’ll discern a difference in the two lines of products at that time, although the soil quality difference between the fields might explain any distinction.  We’ll see!

Mowing Sorghum Sudan & Cowpea Cover Crop – Wow That’s Alotta Mulch!

I’ve spent this whole weekend mowing our cover crop on our neighbor’s 25 acres, and I’m still not done!  Wow, the sorghum sudan got away from us big time!  The average height was around four feet, but in some areas, it was starting to form seed heads, and the tops reached up to 10 feet.  It was kinda terrifying mowing stuff this tall, especially on a slope, but fun at the same time.

When sorghum sudan gets this tall, its stems can get close to an inch in diameter.  This isn’t good for our plan to rotovate (shallow-till) all the plant matter into the soil so it can decompose and eventually transform into organic matter.  Stems this thick are very fibrous and will take a long time to break down, and we need good decomposition so rough plant matter won’t foul the planter when we plant our winter cover crop in late August. We’ll see what happens!

Thankfully, our bush hog is a good shredder.  Alfred at AgVerra advised us to bush hog the crop twice.  The first time we set the bush hog at the tallest setting, going very slowly in our tractor’s second-lowest gear.  The second time we drove faster with the bush hog at the lowest setting to get a good shred on the thick standing stems.  This worked really well.  It takes forever, of course, but the huge amount of plant matter will hopefully be worth it!

Going so slowly on the tractor gave me plenty of time to observe the crop.  The cowpeas looked really good in most places.  Even though they were getting shaded by the soghum sudan, the cowpeas were dark green, healthy, and just about to flower.  I’d definitely plant this combination again, using more cowpeas and not letting the sorghum sudan get so tall!

It’s nice to think about how much good this cover crop is doing for the soil!  The size of plants above ground are mirrored in the size of their roots below ground.  With a crop this tall and thick, that is A LOT of root mass below ground!  When the crop dies, the roots will decompose, transform into some organic matter, and create lots of channels in the soil.  These channels are nice airways, allowing for better water infiltration and making good tunnels for earthworms.  Also, since plants are photosynthesis factories, shredding all of this plant matter and giving it to the soil means we’re feeding the soil all the carbon, hydrogen and oxygen that the plant has assimilated from air and water, not to mention all the plant goodies – carbohydrates, vitamins, plant hormones, etc.  Since we’re not removing anything from the fields, the net benefit to the soil is huge!

We’ve heard that after a good cutting, sorghum sudan will send down even deeper roots and put on more leafy growth.  This will be great for rotovating some green matter into the soil to mix with all the brown mulch material.  We plan to rotovate in early August.  We’re working on making a front-mounted boom sprayer for our tractor.  We aim to spray the mulch with microbes, enzymes and sugars to speed the decomp process and to rotovate all in one trip across the field.  We’ll let you know what happens!

Update on Sorghum Sudangrass & Cowpeas Cover Crop, and Groundhogs Show How Bad our Soil Is

Unfertilized sorghum sudan cover crop 30" tall seven weeks after planting

In this earlier post, I laid out all our hopes and dreams for our very first cover crop attempt.  This cover crop begins our restoration effort to help our neighbor’s fields recover from abuse and years of no-till roundup ready soybeans.  We want the cowpeas and sorghum sudangrass to fight weeds and to provide a lot of biomass that will eventually turn into organic matter.

Update

The sorghum sudan and cowpeas emerged and established nicely.  We’ve had nice amounts of moisture this season.  The sorghum sudan is about 30 inches tall and the cowpeas are about 6 inches shorter.   We planted both on April 30th; this is slow growth for sorghum sudan.  Its color is a kinda sickly yellow-green, and its leaves are narrow, signs we interpret as nitrogen deficiency.  With organic matter around 1.5 to 2%, the soil has very little capability to supply nitrogen to growing plants.  The cowpeas, which look better than the sorghum, are probably supplying some nitrogen, but the demand likely far outpaces the supply.

Weed Fighter and Biomass Provider

Cowpeas well-established, but getting shaded by sorghum sudan

Plenty of weeds are growing too, especially common ragweed and roundup resistant marestail.  But so far, the sorghum sudan is outpacing them.  Regarding biomass, we decided not to fertilize even though we know the sorghum sudan loves nitrogen because fertilizer is so expensive and because the rate of growth is meeting our low expectations for our first cover crop attempt.   We want lots of biomass to till in later this summer, but not so much that we feel completely overwhelmed in our first go at rotovating.  We also want the biomass to break down quickly so we can plant the winter cover crop by the end of August.    

Groundhog Phenomenon

Around groundhog holes, sorghum sudan is twice as tall, thicker, and a deeper green

The groundhog dens have a story to tell!  Around each entrance, the sorghum sudan is twice as tall, a darker green, and has much thicker stems and leaves.  It feels like the groundhogs are mocking us!  What’s going on?  Obviously the soil around the entrances is much better than the “topsoil” in the fields.  Louis Bromfield in Pleasant Valley wrote about how groundhogs drag subsoil up to the surface, and if your crops look better around groundhog holes, that’s proof that your subsoil is better than your topsoil.  Sad, sad, sad!  I’ve also heard that groundhogs poop around their den entrances to fertilize what’s growing there so it provides better cover.  Based on my limited knowledge, I’m going with the poop.  Mr. Bromfield could be right, especially since some nutrients like calcium, sulfur, and boron leach down into the subsoil so easily, but I’ve soil tested the groundhog soil, and it’s worse than the surrounding field’s soil test.  I believe that the fields’ limiting factor is microbes – bacteria and fungi living in the soil.  Groundhog poop can supply that, and microbes help the soil come alive and help deliver nutrients to plants.  We see the same amazingly better plant growth around compost piles on our fields.  Even though it’s a bummer, it’s helpful to see this difference.  It’s a reminder of where we’re headed and how much better our grass and crops will grow… eventually.

Our Plan

Man, I wish we had hoardes of animals to provide these microbes!  We don’t have the time to take care of animals right now, so we’re investigating soil inoculants.  They’re pretty cheap (around $5 per acre), and they can help jumpstart soil life.  We plan to inoculate the sorghum sudan and cowpea cover crop just before we rotovate it in.  Also, when we plant the next cover crop, we plan to mix the seeds with mycorrhizal fungi.  This is probably the most important inoculant, one that is tied closely with organic matter creation in the soil, and one that early evidence shows is easily destroyed by lots of roundup.  I’ll talk more about this in a later post.

What’s Next

As described in the earlier post, we want the sorghum sudan to grow to about 3 to 4 feet tall, then mow it so it will set down deeper roots.  We’re hopeful it will grow that tall by the time the ragweed and the marestail start to set seed.  No matter how tall the sorghum is, we’ll mow for weed control.  We’ll wait one to two weeks for a green regrowth, spray the crop with inoculants, then rotovate it in.  I’ll let you know how it all turns out.  Thanks for reading!

Sorghum Sudangrass and Cowpeas Cover Crop

Planting sorghum sudangrass and cowpeas using St. Mary's County's drill

We’re trying out our first cover crop on our neighbor’s fields.  Like our fields, our neighbor’s land was farmed in roundup-ready soybeans for a good while (we think 10 years).  Organic matter is very low, around 1.5%, and the soil seems lifeless.  Instead of immediately planting perennial grasses like we did with our fields, we’re going to give our neighbor’s soil some extra TLC and a good dose of tough love (disturbance) to try to jump-start this soil into healing itself and becoming hospitable to soil life.

Because summer is approaching, we decided to plant sorghum sudangrass and cowpeas as a cover crop.  Both of these love the heat!  Sorghum sudangrass is a cross between sorghum (relative of corn) and an African grass.  Cowpeas are good ole’ black eyed peas.  We’re hoping the sorghum sudangrass will grow thick and tall and provide support for the climbing cowpeas.  Like corn, sorghum sudangrass loves nitrogen, and the cowpeas are a legume, so we want the cowpeas to fix nitrogen and provide it to the sorghum sudangrass.

Our Goals

sorghum sudangrass

Organic Matter:  Our primary goal for this cover crop is to provide tons of biomass to the soil.  According to this very useful handbook on covercrops, sorghum sudan is “unrivaled for adding organic matter to worn-out soils”.  It quickly grows 5 to 12 feet tall and usually results in at least 2 tons of biomass per acre.  We plan to kill and incorporate this biomass into the soil by rotovating.  With the help of soil life, this biomass will decompose and start to become organic matter in the soil.    Cowpeas grow quickly too and should provide another ton or so of biomass per acre.  Compared to the stiff, crunchy sorghum sudan biomass, cowpea biomass (vines and leaves) is softer and will break down quickly.  After going from year after year of soybeans, we think the soil life will like snacking on these two crops for a change. 

Weed Choker:  After many years of roundup-ready soybeans, the weed pressure in these fields, especially with round-up resistant weeds, is immense.  Both of these cover crops have been shown to out-compete weeds, but sorghum sudan is especially great at it.  This crop actually kills weeds by secreting allelopathic compounds from its seedlings, shoots, leaves, and roots.  The same handbook cited above, page 107, says this compound is strongly active at extremely low concentrations, comparable to synthetic herbicides.  Amazing! 

Iron and Clay cowpeas

Healthy Disturbance:  The tough love I mentioned above is all about disturbance.  This soil has been in no-till soybeans and sprayed with roundup for many years now.  It has gotten very little food in terms of plant matter.  By growing very strong and dense covers and incorporating all that plant matter in the soil by shallow tilling, we intend to shock the soil in a good way and jump start it into heading in the right direction.  Nature uses disturbance quite a bit to initiate renewal (think of forest fires or huge buffalo herds).  We’re convinced that our own fields would be better off if we planted successions of cover crops instead of perennial grasses.  This is the 3rd season we’ve had grass, and the grass gets a little better every year, but the soil seems stuck in a bad place in terms of soil life (crusty, dusty soil, very few earthworms, etc.). 

Method and Cost

We rented St. Marys County’s no-till drill (planter) and drilled about 30 lbs per acre of sorghum sudan and 15 lbs per acre of cowpeas (Iron and Clay variety) on April 30th.  We inoculated the cowpeas with the bacteria that help cowpea roots fix nitrogen.

Seed Cost = $1,175.  (15 bags of sorghum sudan at $30 per bag bought locally, 7 bags of cowpeas at $60 per bag + shipping, inoculant = $35)

Drill Rental = $200

Diesel = $30 (~ 7 gallons)

Labor = $160 (8 hours at $20 per hour)

Total = $1,565 or about $70 per acre (22 acres total)

This being our first cover crop, we have no basis on which to judge the cost, but the cost seems high to us.  In the future, we intend to lower the seed costs by only buying seed that’s available locally (no shipping costs).  We can also lower the diesel and labor costs by getting more experienced with planting different seeds and learning to use the drill.  We had a hard time adjusting the drill to spit out the seeds at the right rate – this took about an hour.  We were also moving the tractor very slowly in order to notice groundhog holes and dodge them in time. 

Our Plan for the Growing Season

Grow & Mow:  As long as the cover crops are out-competing all the weeds, we’ll let the sorghum sudan and cowpeas grow until they’re 3 or 4 feet tall and then mow them.  The cover crop handbook says this encourages the sorghum sudan to tiller and put down even deeper roots for regrowth.  Deeper roots are fantastic – they go into the subsoil, break up compaction, and bring up long-lost minerals and put them in the plant.  When we incorporate the plants into the soil, the minerals will be placed in the top soil and the roots will eventually turn into organic matter. 

Fertilize?:  We haven’t decided if we’ll fertilize or not.  We’ll watch the sorghum sudan, and if it’s starting to look wimpy and nitrogen deficient, we might spread some ammonium sulfate.  It’s $12 per 50 pound bag, and each bag has just over 10 pounds of nitrogen in it.  We’d probably spread at least 50 pounds of N per acre, so the cost could add up quickly.  However, ammonium sulfate also supplies nice amounts of sulfur, which this soil needs badly.  We’ll see – we might end up in a situation where it’s beneficial to “buy” more biomass by fertilizing with ammonium sulfate.     

Rotovate & Wait:  After a good re-growth, we’ll kill the cover crops by rotovating them into the soil, probably in early August.  A rotovator is like a very wide garden tiller for a tractor.  If the sorghum sudan does produce a lot of biomass, we will need to give the soil 2 to 3 weeks to start breaking all the biomass down.  By the end of August, we’ll plant the next round of cover crops for the fall/winter season.  We’ll look for crops that this soil hasn’t seen for a long time, probably cereal rye and hairy vetch. 

Updated June 23, 2011 here.

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