Scents of Spring

written by

Joel Salatin

posted on

April 8, 2025

Why does Polyface smell like a brewery right now?  Because we're pigaerating.

It's one of my most enjoyable smells of spring because I know it's converting fermenting bedding into aerobic compost.  And I don't have to do anything but enjoy the wafting, wonderful odors.  

I wish I could package the odors and send them to you, but you'll just have to imagine it.  Or come and visit.

In the winter, when we feed hay to the cows, we soak up their manure and urine with wood chips and old junky hay.  

Let's go back to the 1960s.  

We had about a dozen cows, and each weekend, when Dad was home from his town accounting job, Saturday morning chores included shoveling out the concrete barn floor.

Dad designed and built a V-slotted feeder gate that we would push through the hay stack as the cows ate the hay off the face.  It was a beautiful picture of conversion.  

Hay is simply dried grass; think of it like grass raisins.  

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Cows lined up at the gate, ate hay, and pooped out their rear end--an extremely visceral look at rapid

decomposition.  I view the cow as a Nascar compost pile, rapidly converting carbon into concentrated fertility.

Dropping some 50 pounds of manure and urine daily, these benevolent beasts placidly go about their business without a care about toilet etiquette.  They poop anywhere.  The concrete pad under the haystack grew dimensionally as the cows ate through the stack during the winter.

If we didn't clean it out, they'd get dirty; hence, the Saturday rendezvous with the cow toilet.  

We'd shovel it into a manure spreader and spread it on the field.  

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A manure spreader is one of the coolest machines in the world.  

It has beaters and spinning fingers that fling the manure out in a nice pattern, scattering it on the ground.  Think of it like a huge butter-knife to spread the cows' goodies on the field like a giant piece of bread.

We started noticing something.  What we spread in January and early February didn't make any difference on the soil when spring came and the grass greened up.  But what we spread in late February and early March, right at the end of winter, made the grass turn dark green and grow like crazy.  The manure spreader strips looked like green paint on the field.

What was the difference?  Same material, same cows, same field; different time. 

In short, that fresh manure and urine were full of nutrients that were highly soluble and volatile.  If it snowed or rained, they washed into the groundwater, away from the topsoil.  If it was dry, they vaporized into the atmosphere - we all know what that smells like.

This is why New York City, many years ago, made it illegal to spread manure on the entire Hudson Valley from early December until about March 1.  

Manure spread during that time ended up in New York City's water supply.  

Why?  

In the winter, soil microbes go to sleep for a long winter's nap.  Earthworms curl up into a ball and await warmer soil temperatures.  Essentially, the soil sponge shuts down, unable to metabolize those dead-of-winter nutrients, regardless of whether they're organic or not.  Soil microbes don't eat when they're asleep.  Kind of like people.

With that observation, we realized we needed to somehow hang on to those nutrients through the dead-of-winter and await spreading when the soil began to wake up during spring warmer temperatures.  We needed carbon to bind the nutrients in a chemical sponge, to stabilize them.  We began searching for carbon and found Staunton's (our nearest city's) leaf pile.  I spent many an hour hand-shoveling leaves into our pickup truck, then bringing them home.

This was the beginning of our "carbonaceous diaper" concept.  

With only a dozen cows, it was not a tremendous amount of shoveling.  The carbon gave the cows a nice clean lounge area; every few days, we'd cover the manure and urine as things got a bit sloppy, and give the cows a nice clean lounge area.  When spring came, we'd haul it to the fields in the manure spreader, and it started to really show vitality.

We knew we were onto something.  

Manure-spreader-spring.jpg

As the fertility cycle increased grass growth, we realized we needed to up our game on the carbon and the

ability to spread it.  We bought a wood chipper and began chipping branches from our firewood work.  

Then the bedding started getting deep enough to ferment.  That presented new challenges because fermentation creates pickling aldehydes toxic to aerobic microbes inhabiting the top six inches of soil.  It's like salt water and fresh water: completely different microbial communities.

We needed to convert the anaerobic bedding pack to aerobic before spreading.  

That pushed us into composting.  

By this time, we're in the early 1980s and able to feed 25 cows.  

The first couple of years, I hand shoveled the bedding into a compost pile about 8 feet wide, 5 feet high, and 45 feet long.  You know the old adage:  "The older I get, the better I was."  The compost was magic.  It still is.

Soon, we were up to 40, and then 50 cows, and I asked a neighbor with a front-end loader to come and dig it out so I could make windrow compost piles.  We did that for years until I had the idea of letting pigs do all that aerating. 

I did a small experiment with two pigs, and it worked beautifully; now we were off to the races. I put corn in the bedding and let the pigs search for their food; in doing so, they went through the manure pack like a big egg beater.  

Hence, our term "pigaerators."  

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Today, we use 80 pounds of corn per cubic yard of carbon and dozens of hogs to turn mountains of carbonaceous diaper into aerobic compost that drives our fertility engine.

By the mid-90s, we purchased our first front-end loader, upgraded our chipper, and augmented our own carbon with leaves from Staunton's pile - I'd drive the tractor down there and we'd fill a dump truck.  

Fertility continued to improve and we were able to increase to 75 cows.  

It was steady, strategic progress in soil development and fertility, all created by leveraging the winter-generated cow dung into aerobic compost.  And those sweet conversion smells became a spring regular. 

Today, we have hundreds of cows and an industrial chipper, three manure spreaders, several front-end loaders, and hundreds of tons of compost created by a hundred hogs.  

It's a wonderful sight.  

You can almost feel the earthworms dancing, knowing that soon they'll have compost spread on their heads.  Happy days.

If you visit the farm right now, you'll get to enjoy that special aroma of fermented manure and urine turned into compost that smells so good you could almost put milk on it and eat it for breakfast.  

The pigs will finish all this work by the end of April.  

For those of you who have read Omnivore's Dilemma by Michael Pollan, the pigaerating is what captured his attention and made him return to Polyface for a week in the summer and choose to feature us.

This was beyond organic.  It was grass farming to the third degree.

We welcome you to experience the magic of pigaerating.  And oh, the aroma.  It's the aroma of magic happening.  Come and enjoy.

Joel

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