Farm Scale

Making Biochar for Farmers

If we are going to reduce the amount of carbon dioxide in the atmosphere in order to stop the greenhouse gas effect, we must do more than conserve energy and use sustainable fuel sources.  We have to actually remove carbon dioxide from the atmosphere.  Nature already does this.  It pulls carbon dioxide out of the atmosphere through photosynthesis and stores carbon in plant matter.  But when we burn it or let it compost or rot, the carbon is joined with oxygen again and goes back into the atmosphere as carbon dioxide.  The problem gas.

To break the cycle, we can actually keep the carbon in the soil by making biochar, charcoal.

It’s something that farmers can do to help themselves by improving their soil.  And help the rest of the planet!

If biochar is going to be used by farmers it has to be able to be made by farmers:  it not only has to be relatively convenient for them to put into their fields but also into their already busy workloads.  And it has to be in a quantity that can be applied to acres of farmland.  It has to be made by the ton!

First, meet Dirk-Jan Rosse, who has been experimenting with making biochar in place.

Dirk-Jan Rosse lives in farming country although he calls himself a “digger”, running an excavating company.  Since childhood he has prowled all over the woods and fields of northern Dutchess County, NY, where he still runs across traces of charcoal-making from the days when it was used to smelt the iron for weapons in the Revolution and Civil War.

Dirk-Jan has a lot of surplus wood on his own property.  He milled some lumber for his own use, but there was an awful lot more than he needed for himself and there was not much of a local market for firewood.

He has been thinking about how to make charcoal at a scale that would suit a farm using equipment available to a farmer. But being in the excavation business, however, he had his own commercial earth-moving gear that you would not really find lying around a farm.  This allowed him to ramp up the scale and the speed of making some tests, but on a smaller and slightly slower scale everything could also be done by tractor with a bucket and grapple.

He remembered those remains of charcoal pits and kilns.

His plan is quite simple: rather than make biochar someplace and then cart it to the field, why not actually make it in the field itself?  It would be based on a traditional way: covering a pile of scrap wood, tree clippings, cut-offs, etc. with dirt and letting it pyrolyze right on the spot.  The same dirt that forms the “retort” would end up as the home for the charcoal.

There is no apparatus required.  Just the existing dirt and some bad hay (of which there is plenty where we live).

What needed to be tested was the design of the pile, how the wood should be stacked, and what kind of air or smoke openings should be placed.


Again, the Bobcat can be replaced by a tractor’s bucket loader and grapple.

It’s time to light up!

After a few days of smoldering, the pile was ready to be opened.  Well, in truth, we were dying of curiosity!

For this much charcoal we need a REAL shovel…

This is only a small fraction of the pile.  There is plenty of good carbon to be put into the soil that has been taken out of the air.

The experiment is not over.  There will be more piles to make biochar and to improve the process: the smoke needs to be burned off, the air-flow improved…  the charcoal will need to be matched with appropriate compost…

The moral of the story:



A Biochar Corn Harvest

A fallow field, one half remained fallow and the other half tilled in with biochar. And then we left the field untouched for 2 years. We did not add any fertilizer or pest control. Just left it alone. We ran the disc harrow over the land and planted some sweet corn on the whole field.

You can see the difference below, filmed in real time.


Harvesting Goldenrod

Goldenrod is harvested with the same equipment as hay — a cutter, a rake, and then a baler.  For those who are unfamiliar with this equipment, the following is a short course in Farming 101.

First, the plants must be cut.

A few days later Dirk-Jan and I were in a far corner of the same field and we discovered some monster Goldenrod.

The cut golden rod still has some flowers and leaves which are not needed for pellets.

Golden Rod in Field

The plants are allowed to stay in the field for a couple of weeks so most of everything other than the stalk comes off in the process of retting,  (yes, similar to what it sounds like, rotting).  This allows the soft and nutritious material to return to the earth.

Retted golden rod

This leaves the stalks lying loose all over the field.  Not at all efficient for the baler to pick up.

Messy field

It now calls for raking.

The baler straddles the windrows and picks up the stalks.  This baler is called a round baler for obvious reasons.  You might have seen square (actually rectangular) bales which are quite different.

If the weather has been dry enough, the rake and the baler can run at the same time.  It’s a coordinated “dance”

The finished product, waiting to be picked up and taken to the pellet mill.

Finished Bale

Each one of these bales has the equivalent amount of energy as 40 gallons of oil when made into pellets for heating.  That’s money that stays here, not only in the States, but in the county!  It is carbon neutral; it does not pump carbon dioxide into the atmosphere from fossil fuels. It is renewable and we can look forward to a new crop every year.

Now it’s off to the pellet mill!


The Pellet Mill

The bales of goldenrod stalks were taken a few miles away to Dirk-Jan’s pellet mill. The bales are put into a huge grinder and then into a hammer mill to become a powder which, in turn, is fed into the mill.

The mill compresses the fine powder under very high pressure and heat and forms the pellets.

The heat of the mill produces the steam seen in the film.