Charcoal in agriculture: Numerical Data

Tom Miles

Charcoal in agriculture: Numerical Data
Rich Haard, Propagation Manager, Fourth Corner Nurseries, Bellingham, Washington, January 11, 2008

This is addendum to my earlier report of

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

posted recently at

I have been looking at the data sets of the soil analysis we conducted on the plots on June 25, 2007 and October 30, 2007. The first soil samples were taken about a month after project setup and planting and the last was at the end of the growing season. I sampled with a hand held soil coring device, and took samples uniformly in each 17 foot long test bed. They were dried and screened to remove lumps and pieces of wood/charcoal etc.

We sent the samples to the soil lab and had a standard soil test run with for organic matter, major, minor and trace elements, Cation exchange capacity (CEC) and associated base exchange percentages for K, Mg and Ca.

There were a few anomolies in the data set that should not be surprising as there is no reason to expect a 500 long by 4 foot wide section of a farm field be uniform in analysis. In addition, without doubt there is sampling error. One of the control samples read abnormally high the first reading and then fell into the same pattern as the other control plot. This is the reason why control ranking is skewed in the data set. Otherwise the data is remarkably consistent and I feel I have learned something about using compost and charcoal.

I obtained a program to plot on an x,y and z axis any three items for each treatment plot. I chose to look at Organic matter, CEC and Phosphorus. It gave me a cute 3D image that ranked the data sets on all three parameters at once.

Item by item there were changes from June to October. In all of the plots soil Phosphorus ranged from 5 to 8 (PPM) in the spring and from
7 to 12 in the fall. Organic matter also increased from 3.4 to 6.5 (% ) spring and 4.1 to 7.5 in fall. the CEC also changed 10.8 to 15.3 (MEQ/100g), spring and 9.3 to 13 in fall.

The rankings shown by this program indicate synergistic effect of compost and charcoal. Charcoal1 tended to score higher as is expected since it is a fine powder.

(Cm= compost, F=Fertilizer,C1= John's Charcoal, C2=Larry's Charcoal,C=

If we take all 4 readings (duplicate sets taken twice) as averages, the 3 way comparison, (of OM, P and CEC) , sorted things out this way

Cm+C1 > Cm+F+C1 > Cm+C2 > Cm+F+C2 > C > Cm+F > F+C1 > Cm > C1 > F > C2
> F+C2

Relative rankings 1 to 24 were averaged showing this spread

22, 22,16.5,15.5,13.5,12.5,12,11.25,10.5,8.5,7,6

This indicates to me there is a synergism between the compost and charcoal.

I'm looking forward to more data next season from the same plots

Best Wishes

Rich Haard, Propagation Manager, Fourth Corner Nurseries, Bellingham, Washington