Charcoal in agriculture: Experimental research at Fourth Corner Nurseries

Tom Miles

Charcoal in agriculture: Experimental research at Fourth Corner Nurseries
Richard Haard, Fourth Corner Nurseries, Bellingham, Washington, January 3, 2008


I just finished over the last few days organizing images and data from my charcoal experimental plots. I am presenting a new set of posters showing root systems of the native shrub, Lonicera involucrata or black twinberry that I used as an experimental subject in these treatment plots this summer.

This will be the last of a series of piecemeal postings about my findings on the terrapreta reading list. In time, I will prepare a summary of what I have accomplished this year, the shortcomings, what I feel I have learned from this work about using charcoal and my plans for continuing this experiment for 2 or more growing seasons.

Quick background - my employer, Fourth Corner Nurseries is a bare root native plant nursery. We grow more than 350 kinds of plants for environmental restoration and landscaping purposes. Our farm is 60 acres in 2 fields. Shown here is our east field. Formerly, I have been trying charcoal as a soil additive for several years and this season I attempted a controlled experiment. It did not go without a hitch.

What I established this year was a series of 28 - 17 foot long treatment blocks that are a pair of treatment sets consisting of untreated soil, charcoal only, fertilizer only compost only and combinations of charcoal, compost, fertilizer. In each treatment block 3 kinds of plants were installed: a native shrub, Lonicera; a native perennial - Aster subspicatus; and a vegetable - swiss Chard.
All were selected for their heavy nitrogen consumers and all production was removed from the plots, roots and tops, then the plots replanted and cropped again without further fertilizer, compost or charcoal.

The most detailed measurements accomplished this year is 2 sets of soil chemical analysis completed at a University laboratory. Plant response measurements this year, for several reasons was only visual observation. This set of posters I am presenting today shows subtle but interesting and positive additive effects of compost and charcoal.
Further analysis will be presented at a later date.

How it went. Early April while the plants were still dormant I took 2 year old bareroot Lonicera seedlings trimmed tops and roots and planted in peat/perlite mix in 4X4 inch containers. At these same time I planted
sprigs of Aster
in the same manor. After the plants had firmly rooted into the containers and our field soil had warmed, I prepared a growing bed in our normal propagation field ( Field 13, row 8). The growing bed is about 4
feet wide and 500 feet long. I divided this into 17 foot beds with separate treatments in a systematic way. Here is charcoal 1, a fine powder that was donated by JF Waste energy systems. Here is charcoal 2 a lump and powder mix that
Larry Williams and I
made with a top draft earth covered mound. I am using the lump charcoal because I can observe microbe utilization over time as Larry has been studying for several years.

Here are the charcoal test beds are they appeared before rototilling. In this image furthest is compost only, then compost/charcoal1,then compost/charcoal2,then compost/charcoal 1/fertilizer and so on in a systematic pattern repeating again in a second duplicate set on the north end of the field. In discussing these tests I sometimes discuss each set separately, are are called south set and north set.

Here are the plots immediately after rototilling. Note that the charcoal does not appear to be uniformly dispersed. After harvest with the
lifter-shaker charcoal is better mixed in the soil. Each bed received about 30 gallons of charcoal. Fertilizer and Compost were applied at rates normal for our farming practices.

We planted the plots in mid May and by late June they looked like this and this and this .

By the end of August the Swiss
Chard had matured
and we had our first harvest. Yields were impressive but no trends specific to treatments were noticed.

Here you can see our plot method for measuring yields of swiss chard and also how the separate treatments, Lonicera, Aster and swiss chard have grown together making assessment of total production rather difficult.
In late October I conducted a survey of the Lonicera component of the research plots. It was the end of the growing season but before the frost defoliated the plants.

Here is how the plots looked. My first look at the data that showed a subtle but encouraging trend of improvement from the use of charcoal 1.

In this set of images notice that the treatments with compost when combined with charcoal tended to be larger.
The same trend is also noticed in the compost/fertilizer/charcoal combinations. By mid November we were ready
to lift all the plant material from the plots, examine the roots and fall replant with a single species crop for next year. Here we have our lifter shaker harvesting the plants, Lonicera with charcoal staining roots and Rena picking up the plants. Later we replanted with our 4
row seeder
and reseeding with another native shrub species, Oemleria cerasiformis, chosen because it too is an agressive nitrogen consumer.

Finally the posters I have prepared to compare top growth and root growth in each of the treatment sets. I have organized the images according to groups of treatments as follows: The links are to the larger size images for better viewing. Edit note root images were created 11/15 not 10/25

First Groups 1 and 2 the control sets that received no treatment or had charcoal only
Field View

Next Groups 3 and 4 fertilizer sets Edit Roots is labeled as Groups 1 and 2

Next Group 5 South end plots compost set

Next Group 6 North end plots compost set

I think these findings will be encouraging information for John Flotvik and many thanks for his donation of charcoal from his pyrolyser and thanks again to Larry Williams , his thoughtful work and helping when it is most needed.

I am looking forward to another season of data from this set of test plots. Comments, ideas, criticism, discussion whatever are appreciated as I am now preparing my season end report.

Richard Haard, Fourth Corner Nurseries, Bellingham,Washington.

Copyright January 3, 2008
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