BIOCHAR TRIALS 2013
The Kerr Center makes and uses biochar as a soil amendment; it acts roughly like soil
organic matter in holding water and nutrients.
Twobarrel nested biochar retort
click here to learn how to make and
use one.
We wanted to know how biochar made from different feedstocks
affects soil organic matter content.
We compared eight different feedstocks of which pine needles, pine slash, and hardwood branches are shown here.
Intern Jon Pollnow checking a fresh batch ofbiochar. The scrapwood in the foreground isused for fuel.
Jon Pollnow taking samples froma fresh batch of biochar
A fresh batch of biochar
Another fresh batch of biochar
We used sand (storebought for uniformity) as the soil medium, due to its low nutrient and
organic matter content.
We ovendried it to calculate its bulk density, in order to know how much biochar to add.
The dry sand's density was 1.47 grams per cubic centimeter, in the range of very
coarse sand.
Each cup holds 16 oz. of storebought sand, enough for a standard soil sample.
Each cup of sand receives an addition of 1.9 grams of biochar (roughly equivalent to 10,000 lbs. per acre).
Each cup received an addition biochar from a different feedstock, including okra...
...corn...
...peanuts...
...sunflower...
...pine needles...
...pine slash...
...hardwood...
...and office paper.
The biochar was ground in glass jars using the butt of a garden trowel.
The ground biochar was sieved to excludeany pieces larger than 1 mm.
Sieved biochar is in the white tray at right.
1.9 grams of this material is added to each cup of sand.
Checking the density of a random biochar sample, to visually gauge how much a given amount of biochar might weigh.
Each ground, sifted biochar sample has the same weight as all the others...
...illustrating the difference in density between biochars made from the different feedstocks.
Each biochar sample is thoroughly mixed with sand...
...creating a marked color changecompared to sand alone.
Each combined biochar/sand sample isindividually bagged...
...and sent to a professional lab to beanalyzed for soil organic matter content.
In a separate trial, bulk biochar pieces were sent to a different lab...
...to compare the length of time that biochars from the different feedstocks will
persist in the soil before breaking down.
Results:
Feedstock Guide for a Two-Barrel Nested Biochar Retort
Biochar Feedstock Research Using a Two-Barrel Nested Retort
The Effects of Added Mineral Salts onBiochar Yield Using a Two-Barrel Nested Retort