[Terrapreta] Charcoal, Earthworms and Switchgrass

[Jeff Davis]

Hi Larry,


Well, for this field you have to wait until it dries up a bit. It's flat
and well drained soil but behind a flood control dam so it is not uncommon
to have 8 ft. of water on it by spring.

How about a post hole digger/drill. Drill some holes every spring or fall,
fill 3/4 with charcoal and top off with the dug soil. It would be like a
8" wide worm. We could call this "Mega-Worming.


Jest an idea,


Jeff



> Jeff-------I have a tendency to use unconventional techniques if I
> think that they will work. In your situation I am working off of the
> barest details of what you are looking at. There are far more ways
> for a task not to work than there are for accomplishing the task.
>
> Your suggestion to press the "charcoal into the soil" may cause more
> soil damage with tire compaction that minimum mixing is worth. The
> word "might" seems significant in this case.
>
> I am back to the disc, except instead of using the disc when the
> ground is thawed, can the disc be used when the ground is in some
> stage of freezing or thawing? It sounds like the cutting of the above
> ground switchgrass with a disc with minimal slicing action in the
> soil is a way to do some mixing of soil, charcoal and grass stems.
> Working on frozen ground will do little compaction to the soil or
> damage to the plants. Consider doing a small test area with repeated
> passes, in two direction, using a disc. This should show you if a
> disc will accomplish anything.
>
> My response is to a technical problem for jump-starting a biological
> process and not related to an energy audit for bio-gas.
>
> In the early nineties I used a skid steer to place woody debris in a
> wetland on my property. The wetland was about 1 acre. This land had
> been used to pasture horses. The problem was that the previous owner
> had allow the animals on this wetter portion of his land during the
> wet season (Whatcom County, up against the Canadian border and in the
> Puget Sound basin).
>
> This resulted in soil compaction on the young alder trees. The stress
> occurred twice a year, from what I could see, during the rainy season
> and during our summer droughts which can form 30 to 90 days. Given
> the glacial clays in this area, that meant that the soil saturated
> for the winter months and went bone dry in the late summer. Many
> alder trees, fifteen years old at that time, had died and the
> remaining trees looked stressed when leafed out.
>
> Hooves, wet clay and tree roots do mix and don't work well together.
> I haven't seen any soil type except dune sand that won't puddle under
> the influence of hooves or tires.
>
> In 1990 there was an opportunity to receive the tree prunings of
> trees being cleared from the local power lines. I probably received
> around 5-600 yards, for free, of knife-cut material plus hardwood
> rounds over three year period. Also I was getting Douglas fir planner
> shaving from a saw mill that bought dimension old growth timber
> (Douglas fir) from dismantled mills and warehouses in the Puget Sound
> basis, close to 150 yards. I used a mid-size excavator to create
> several vernal pools for seasonal ponds. Between the tree pruning
> company, lumber mill and the free stumps (replanted---ah, re-
> positioned) I was able to jump-start the biological process in this
> degraded pastureland.
>
> I have since moved and this project has been doing it's thing on it's
> own. The 5-600 yards of wood chips, partly hauled away, has
> disappeared (via oxidation). The 150 yards of Old Growth shavings
> (400 to 1, C/N ratio) is faded on the edges. Basically the shaving
> pile is intact as I left it with some being hauled away. I have
> aerial pictures taken in Jan 06' with the reflected light off the
> constructed vernal pools (which were created with discrete placement
> of the those spoils) match the puddling on adjacent properties while
> the house-looking-back shows the smaller trees currently on this
> property as compared to the adjacent properties. Currently trees are
> replacing the perennial shrubs. Now, I would be managing for perennials.
>
> I have additional prints that show the minimal, detrimental or no
> impacts of woody debris placement. Small machinery was used in the
> driest, wettest and coldness (frozen ground) weather. A dry wheel
> barrow path through a vernal pool is evident in one picture. In this
> project the vernal pools reduced the plant stress going into the
> summer drought and, now, the alder roots are doing nicely. Ya, I played.
>
> I won't tell anyone that it could easily be returned to a degraded
> pastureland. Put animals on it during the wet season, i.e. compacting
> the soil. I can send you some pictures if it helps.
>
> I hope that this gives you some help-------Larry




-- 
Jeff Davis

Some where 20 miles south of Lake Erie, USA