Your Future Favorite Sci-Fi Horror Movie Will Star Soil Bacteria.

Fruiting body of Myxococcus xanthus (Picture: Max Planck Institute for Developmental Biology)

Fruiting body of Myxococcus xanthus (Picture: Max Planck Institute for Developmental Biology)

Screenplay writers looking for the next sci-fi blockbuster should look to soil microbes for inspiration, especially the very horrific bacterium Myxococcus xanthus.  Far different than peacenik single-celled bacteria we all learned about in school, M. xanthus is a social bacterium that communicates and organizes itself into multi-cellular, three dimensional structures made up of thousands of cells that hunt for food and survive harsh conditions together.   Like a wolf pack, the structure travels through topsoil as one unit searching for prey.  When the structure encounters potential prey, it works as a group to secrete powerful enzymes into the environment to kill and digest the prey outside the structure before drawing in the digested nutrients.  According to Rice University scientist Oleg Igoshin, these enzymes are potent antibiotics that kill other species and chew up prey proteins into small segments.  Check out this microscopic video showing 100,000 cells of M. xanthus digesting 10 million cells of E. coli.

Imagine if we saw this social-self-assembly-enzyme-spewing behavior exhibited by large animals that are familiar to us?  Freaky!  And M. xanthus is just one out of 10,000 to 50,000 microbe species contained in just one teaspoon of soil.  Soil is amazingly complex and so much more than the dirt that holds up our corn and soybean plants.  It’s a living, breathing, violent ecosystem and one we still know relatively little about.  In my opinion, soil’s complexity and humanity’s lack of knowledge calls for caution in soil treatment.  For our farm, we’re exercising caution through little to no tillage and no “cides” (pesticides, fungicides).  Best to leave it alone and let all the freaky microbes do their jobs.

Grass vs. Legume Competition – Does the Winner Tell Us Anything?

If you’re the one who’s been reading this blog regularly :), you know that since May 2011, we’ve been planting summer and winter cover crops to improve our dusty, depleted soil.  We’ve never planted just one species – it’s always been a mix of at least two different plants – at least one grass and one legume.  (For newbies, legumes work with soil bacteria to make their own nitrogen.  Examples:  beans, peas, vetch, clover, alfalfa, etc.)

As the soil health gets better & better over time, I think I’m seeing some of the fields expressing their healthy transition through the types of plants (grass vs. legumes) that are growing.  Could I be seeing things and reading way too much into them?  Quite possibly!  But it’s interesting to think about… at least for me!

Take this picture of our neighbor’s east field from May 2012.  It shows what we lovingly remember as our 3-foot tall “vetch jungle mat”.  But wait… something is missing.  Where’s all the rye we planted with the vetch?  Virtually no rye germinated.  What you see in this pic is 100% vetch.  We were happy to get vetch’s wonderful weed-blocking services and all that free nitrogen.  But we wondered… what in the world happened to the rye?  Why didn’t it germinate and grow?

May 2012.  Neighbor's east field.  Vetch jungle mat.  No rye germinated.

May 2012. Neighbor’s east field. Vetch jungle mat. No rye germinated.

Now check out this pic of the same field one year later, in May 2013.  We planted a winter cocktail of radishes, oats, cereal rye (we’re optimists), austrian winter peas, crimson clover, and lupines.  Both grasses – oats and cereal rye – germinated and grew stupendously.  The oats died in January from hard freezes, but you can see lots of healthy rye (looks like tall, skinny wheat) growing in this picture, along with crimson clover and peas (legumes).  We never put nitrogen fertilizer on this field, so why the extreme change in grass growth in just one year (non-existent to beautiful)?

May 2013.  Neighbor's east field.  Cereal rye growing well with legumes (crimson clover and peas).  Yellow flower is year-old mustard, planted in May 2012.

May 2013. Neighbor’s east field. Cereal rye growing well with legumes (crimson clover and peas). Yellow flower is year-old mustard, planted in May 2012.

Curious, I googled “grass legume competition” and found lots of information and research results, but no solid conclusions.   Many research studies tested grass/clover pastures at different nitrogen fertilization rates and found that more grass grew with higher nitrogen.  Makes sense, because grass loves nitrogen and clover can make its own.  Some researchers documented that added nitrogen made pasture grasses grow so big so quickly that the clover got shaded out.  But, other studies found that different mowing heights and times resulted in the same grass vs. clover effects.  So the precise effect of nitrogen on grass vs. legume competition isn’t clear, but it’s generally accepted that grass loves nitrogen.

We subscribe to Acres USA for the eco-farming ideas.  Many wise old timer farmers contribute to that magazine, and I’ve read from them that legumes are “rescue plants”.  Meaning, it’s hard to get grass to grow well on poor soil, but legumes will germinate and grow well enough on bad soil and will eventually contribute some nitrogen to the soil, enabling grasses to grow better.

So IF legumes are rescue plants AND grasses grow really well with good nitrogen but legumes could take it or leave it, the two pictures of our neighbor’s east field might tell a story.  Maybe the 2012 vetch grew like crazy and the rye didn’t because nitrogen was lacking.  Then, maybe the vetch provided enough nitrogen to get soil functioning so the 2013 grasses (oats and rye) could grow.  I could be dead wrong in drawing these conclusions, but maybe not.  What do you think?  Anyone else out there have thoughts or experience with grasses competing with legumes?

Thanks, Year 2013, for the Extra Soil Organic Matter!

Ho ho ho Happy Holidays!  According to our 2013 soil test results, organic matter has increased again in most of our fields.  As I’ve mentioned in many previous posts, organic matter is extra important for our sandy soil.  With very little clay content, our soil can’t hold many nutrients, not enough to support plant health anyway.  So we’re depending on organic matter to do that job, plus hold water, improve soil texture, provide homes to soil life, etc.  Put simply, organic matter is the keystone to improving our worn-out soil.

Here’s the 2013 update to our chart.  It shows what we’ve planted in each field, plus any tillage, compost or lime applications.  The sparkline graphs at the bottom make it easier to show organic matter trends across the different fields.  They show where each field’s organic matter percentage started in 2010 and ended in 2013, relative to the other fields.

Organic Matter improvement from soil test result data. Click to enlarge.

Organic Matter improvement from soil test result data. Click to enlarge.

At this point, it’s hard to detect a pattern.  

We’ve left two fields in pasture grass (Scott West & Middle) and planted cover crops in the six other fields.  Back in 2010, after getting discouraged from looking at very dull and lackluster pasture grass, I chose to switch some fields to cover crops.  I thought cover crops, because of their huge biomass growth, would result in much bigger increases in organic matter.  So far, this has not come to pass.  All fields increased in organic matter at about the same rate.  Scott West had the biggest increase (87%), but it also started in the poorest position.  The two fields with the smallest increases (31% and 27%) started with relatively high organic matter in 2010.   Scott McCarthy is the field we always refer to as “our best field”.  Plants grow amazingly lush and healthy in this field.  It has the highest 2013 organic matter (3.5%).  Also, its phosphorus levels are four times higher than the other fields.  This field is located next to the old “main house”, so possibly a barn was located here in years past (animal feeds & manure are high in phosphorus).

In summary, there are way too many variables here!  Plus, imagine all the opportunities for sampling error while I was pulling soil samples in the fields.  More data points are needed.

We’re happy that all fields have more organic matter under our management.  We’d love for all fields to get to 4 or 5% organic matter, so they’re about 2% short right now.  With our climate and soil content, 4 to 5% would get our soil to that sought-after moist chocolate cake consistency so indicative of very healthy soil.  We’ll see what the 2014 soil test says.  Happy New Year!

Are Summer Cover Crops the Best Soil Builders?

Why is summer a fabulous time to build soil?  Because the best cover crops for restoring soil love hot weather!  Summer plants, like sorghum sudangrass and sunn hemp, grow giant-like very rapidly and contribute tons (literally) of plant biomass and root mass to the soil.  Winter cover crops will always be extremely important, but they’ll never match the biomass-generating potential of sorghum sudangrass and sunn hemp.

Sunn Hemp and Sorghum Sudangrass

Sunn hemp is a tropical legume that contributes organic matter to the soil, produces nitrogen, and grows well in low-fertility soils (perfect for our degraded farm soil).  And according to the SARE cover crop guide, sorghum sudangrass is “unrivaled for adding organic matter to worn-out soils”.  Exactly what we need!  Both sunn hemp and sorghum sudangrass have the potential to produce 5,000 pounds of biomass per acre, so it’s safe to assume this cover crop grew at least 2 tons of biomass per acre for us.

Healthy 6-ft tall sunn hemp and sorghum sudangrass on July 31, 2013.  Planted on June 1st.

Healthy 6-ft tall sunn hemp and sorghum sudangrass on July 31, 2013. Planted on June 1st.

Giant Cover Crops Provide Giant Benefits

Growing carbon-rich summer biomass is so central to soil restoration because carbon is usually the primary limiting factor of degraded farm soil.  When the hugely tall plants get mowed down, all that high-carbon, coarse mulch protects the soil surface and stimulates a wide array of beneficial life to set up shop and do their soil-service jobs.  Soil bugs eat the mulch and poop out nutrient-loaded pellets (free bio-activated fertilizer).  Earthworms and other critters distribute the mulch through the soil profile, which transforms into much sought-after soil organic matter.

And the roots!  The roots are just as crucial, maybe more so.  During the growing season, roots leak sugary photosynthesis products (exudates) into the soil to stimulate beneficial soil life.  These sugary (carbon) exudates work their way through the soil life food chain and eventually become soil organic matter.  And when a cover crop grows 12 feet tall, the roots likely go down 12 feet, pumping carbon into the entire soil profile and sucking up calcium, nitrogen, and other nutrients that had leached out of our very sandy topsoil.  These nutrients end up in the plant biomass, which is now back on the soil surface and getting munched into new, top quality topsoil by soil critters.  These are just a few of the many benefits provided by a 14-week summer cover crop!

How We Managed

Planting:  We purchased Cover Crop Solution’s Homestead mix and planted it in early June on our worst fields, Scott east and neighbor west.  Seeding rate was 15 lbs per acre.  (Our best fields got a different summer cover crop and then were planted to a perennial pasture mix in August.)

Growing:  By the end of July, the cover crop was 6 to 8 feet tall and green and lush.  The previous cover crop was our legume-heavy winter cocktail, so the sorghum sudan was probably loving all the nitrogen the winter legumes pumped into the soil before they died in late May.  By mid-September, the sorghum sudan was up to 12 feet tall in places.

Mowing:  We didn’t mow until very late, September 21st.  Mowing in early August is a good idea for stimulating more root growth and making the end-of-summer management a lot easier (see pg 108 SARE cover crop guide).  But, we chose to do only one late mowing because of laziness and weed suppression.  In our ongoing no-till cover cropping scheme, we haven’t used any herbicides, and weeds have become a problem.  So we wanted to leave the cover crop tall and thick for as long as possible to shade out and suppress weeds.

Busting the sorghum sudan down to the ground required two mowings:  a first rough cut with the bush hog in the highest position, and a 2nd finishing cut with bush hog in lowest position.  If you do this, watch out for thick sorghum sudan canes ripping off tractor wires during the 2nd cut!

Mowing 12-ft tall jungle forest of sorghum sudangrass and sunn hemp on September 21, 2013.  Pic taken during 1st rough cut with bush hog in highest position.  Look at all that mulch!

Mowing 12-ft tall jungle forest of sorghum sudangrass and sunn hemp on September 21, 2013. Pic taken during 1st rough cut with bush hog in highest position. Look at all that mulch!

Next Cover Crop:  We planted a winter cover crop of cereal rye, peas, and vetch on October 5th.  We rented our county’s no-till drill for planting.  The drill can slice through the thick sorghum-sudan mulch and set the new seed into the soil.

Cereal rye, hairy vetch, austrian winter pea seedlings coming up through sorghum sudan & sunn hemp mulch on October 24, 2013.  Planted on October 5th.

Cereal rye, hairy vetch, austrian winter pea seedlings coming up through sorghum sudan & sunn hemp mulch on October 24, 2013. Planted on October 5th.

With constant signs of depleted soil all around us on our farm, soil improvement is always on our minds.  So it feels very good knowing we’re headed into winter with thick protective mulch on our fields and a nice new winter cover crop growing up through it.  Thanks for reading!

A Fantastic Short-Duration Summer Cover Crop

Three of our fields have improved to the point where we can stop growing cover crops and plant our final pasture grass mix for our future livestock!  These fields have more than 3% organic matter (still not a great %, but pretty good for our very sandy soil), and they consistently produce very lush & healthy cover crops.

Our last cover crop was mature and dying in mid-May.  I want to plant the final pasture grass mix sometime this August so it can grow well this fall before winter sets in.  For summer weed suppression and other benefits, I want to plant something for the summer, but I don’t want to till or apply herbicides to kill it in August before planting the grass mix.   What to do?  How about a short-season cover crop?  Yes!

Many plants make wonderful summer cover crops, but only a few of them (to my knowledge) are short season, meaning they grow, mature, flower & produce seeds within a short timeframe.  Annual plants that are mature will die by mowing.  No tillage or herbicides needed!

I chose buckwheat, sunflowers and oats.  (See my previous post on summer oats.)  Buckwheat matures in seven weeks!  And the sunflowers I chose (Terraza) were 70-day, meaning they flower at 70 days after planting, well within my August deadline.

Bonus:  the sunflowers and buckwheat are beautiful together!  The pic below does not do them justice.  Both have reached over 5 feet tall in some places.   Other benefits include:  great weed suppression, soil texture improvement through buckwheat’s abundant, fine roots, and phosphorus scavenging (getting hard-to-get phosphorus from the soil and putting it into plant available form).  I’m not sure what sunflowers uniquely do for soil health, but I heard they scavenge zinc.

I’m glad the last cover crop for these fields is so pretty!

Buckwheat, sunflowers, oats.  Planted June 1, 2013.  McCarthy field (7/31/2013)

Buckwheat, sunflowers, oats. Planted June 1, 2013. McCarthy field (7/31/2013)

How Do Oats Behave in Hot Weather?

Oats love cool weather.  Farmers plant them in fall or early spring.  But have you ever heard of summer oats?  I couldn’t find any info about oats planted in late spring or summer, but oat seed is cheap, so I decided to try it out.  I needed a summer cover crop that would poop out on its own by mid-August.  Plants that fit this bill aren’t too hard to find, but many of them, like buckwheat, don’t suck up and hold many nutrients.  Oats do.  They are a wonderful “catch crop,” and I needed them to catch all the nitrogen and other goodies my winter cocktail produced and pumped into the soil this spring.  (Nitrogen leaches from soil very easily.)

We planted oats on June 1st in a mix of buckwheat and sunflowers.  I was hoping most of the oats would germinate and grow at least 4 inches before they shriveled in the summer heat.  The oats beat my expectations!  They grew about 2 feet tall, which is about half their normal height in cool weather.  Some of them are starting to seed out now.  They do look puny, but they grew plenty of leaves, which probably means they have some decent root mass going too.  I think with one mowing, they’ll be dead.  We’ve had an extremely wet summer so far, so all the rain probably helped the oats.  Thanks, oats!

Oat seed head.  Planted June 1, 2013 with buckwheat.  About 2 feet tall. (7/31/2013)

Oat seed head. Planted June 1, 2013 with buckwheat. About 2 feet tall. (7/31/2013)

See What a Cover Crop Cocktail Did to Our Farm Soil!

Sorry for the drought in blog posts!  Hubby and I have been working extra long hours sprucing up a rental house to put on the market.  If it sells this time, our dream of leaving our DC jobs and farming full time will become a reality.  Fingers crossed!

I took these pics on May 19, 2013, a couple days after mowing down our stupendous winter cover crop cocktail.  By May it was hugely tall – everything at least 5 feet tall, and some was up to 7 feet in places.  Hubby and I kept talking about the roots – I wonder how deep the roots grew?  I wonder if the soil structure improved?  We got a shovel and went out to the field to see.

McCarthy field, May 2013.

McCarthy field, May 2013.

Here’s the most telling picture (above).  This is a chunk from our best field.  I labeled the healthy soil evidence:  earthworm tunnel holes, fungi threads (fungi are soil’s “network” and give nutrients to plants plus probably many other things we don’t know yet), and many soil animals.  It’s hard to make out the tiny soil bugs from the coarse sand particles, but this soil chunk was crawling with tiny critters!  This demonstrates a huge improvement from where this soil started in 2008.  Back then it was tight and crusty with no signs of soil life.  A shovel-full would not break apart into nice fluffy chunks like it does now.  Porous structure is crucial for letting air and water through the profile and for giving soil life nice homes so they can do their jobs.

McCarthy field, mid-May 2013.

McCarthy field, mid-May 2013.

And earthworms!  I cannot believe three of these dudes were in one shovel-full of soil!  Until this spring, I’ve been unable to find adult earthworms, so three is a great excuse to break out some champagne!

McCarthy field.  Mowed mulch 14 inches thick.  May 2013.

McCarthy field. Mowed mulch 14 inches thick. May 2013.

Here’s a rather boring pic of what our bushhog left behind.  MULCH!  Soil life loves this stuff on top so don’t till it in!  A thick mulch layer keeps soil temperature and moisture steady during weather extremes.  Mulch keeps soil life comfortable.  It is soil’s protective cover and the key for our soil’s improving health.

Thanks for reading!  And leave a comment if you have any questions or want to say anything.  I’d love to hear from you!


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