Wednesday, May 07, 2008

4 Inches of Topsoil...

That is what we have at the farm after doing some digging for our perk test. Actually we have about 4 inches of topsoil, 6 inches of a mix of topsoil and clay, and then at least a couple feet of clay (they only dug down a bit over three feet). It's not perfect, but it is pretty common for this area and we probably couldn't have found anything much different if we tried. I guess all that clay could be a bonus if/when we build a pond, but for right now it is kind of a bummer.

The bummer factor is that our ground didn't perk, so we have to go with a more expensive septic system. If we would have had some good perking land (which we are now finding out isn't super common in our area) our septic system could have cost as little as $3,000, but since we have to have to install a system that is quite a bit more involved it could cost as much as $7,500. That isn't exciting, but you need a septic system.

The other side of the soil coin is that it would be nice to build some more topsoil over time so that we could have more organic matter (OM) on our ground soaking up the water (instead of running off the ground). Last summer we collected coffee grounds from a local coffee shop in town and spread them around our garden. Yesterday when my wife was putting in a few plants she noticed more earthworms than the year before in the areas where she heavily put the grounds. Worms are great components of soil building so we will want to encourage their presence as much as possible.

Hmmm... maybe I can get coffee grounds from all over town and fill a spreader!


Yeoman said...

Re the item mentioned in the last sentence of today's entry. . .

Rich said...

Here are a couple of articles about building topsoils:

The method that I find most interesting is the one developed in Australia by P.A. Yeomans called the Keyline system that was supposed to increase soil fertility and build topsoil. He was supposedly able to build 10 cm of friable black soil within three years.

His techniques involved a certain amount of tillage with a modified chisel plow in the beginning, (which could be a problem in most pastures), but his techniques are basically a matter of "capturing" moisture in subsoils. When the moisture is captured, it increases the soil fertility which leads to an increase in topsoil.

I once saw a reference that running a subsoiler perpendicular to the slope causes enough water infiltrarion that it violates the Water Laws in some areas, which makes me believe that it might actually be an effective technique for increasing moisture levels in subsoils. So I was thinking that instead of using a chisel plow, a simple one-shank subsoiler could be used to create "channels" spaced on 15-20 foot contours parallel to the Keyline (makes more sense after you have read the literature).

Even if you don't plan on any tillage operations, the literature contains some interesting information about building soil fertility, erosion, water catchment structures, etc.

The best technique for building topsoil is probably going to be a combination (or system of rotation) of all the techniques suggested. Subsoiling, grazing, a seeding followed by an intensive haying technique, etc.

It might be interesting to dig some 4' post holes scattered in a grid over your pasture to examine the soil profiles, followed up with a reexamination in the following years to see the changes.

Rich said...

I've been considering how best to implement some of the methods outlined by P.A. Yeomans (without major tillage), and it occurred to me that it might be possible to take an area like your pasture (which hasn't been grazed in a while), then simply cut the grass and rake it into windrows on 20' intervals running perpendicular to the slope (similar to how a terrace would be) following the principles laid out in the Keyline method..

The windrows would act similar to a terrace, catching and directing water to increase infiltration and slow erosion. In addition, the increased organic material in the windrows would create conditions more favorable to earthworms. Future paddock divisions and tree plantings would then be located in regard to the Keyline method. The hardest part would be determining the Keyline and laying out the windrows to follow it, but it seems like it would be a relatively easy low impact method to try (no tillage required).

Running a subsoiler or applying a line of compost (or fertilizer) along the windrow line could always be done in the future (like icing on the cake) to enhance the effect.

Thanks for stimulating my thoughts on this subject.

Concord Dad said...

Any Thought of a composting toilet? Much more affordable, but maybe not right for your application.

Ethan Book said...

Rich - Thanks for the links. I have read a little bit about the Keyline system in one of my books recently (can't remember which one). It does sound like an pretty interesting idea, and one that I plan on researching more because I think it would work well with the lay of our land.

Concord Dad - To tell you the truth we did actually think about it, but I'm not sure about the gray water ... our doesn't even like people to put in mechanical septic systems...

Steven said...

We are now rotating 5 dexters through our grass, weeds, and volunteer wheat while we wait on our new pasture to grow. Well, yesterday I saw what I first though was an ant hill, then I was a cow paddy that was normal on one half and like an ant hill on the other half (it was made of little bits of dirt). Kicking it to the side you can see a hole under each pile.

After some research I'm happy to see that we apparently have plenty of dung beetles. Does anyone have any first hand experience with the benefits of dung beetles?

Rich said...

"...the benefits of dung beetles?..."

I think this article even has a section that talks about a "dung beetle farm", to help increase your dung beetle populations.

Steven said...

:-) I JUST read that after posting my comment. After reading it I wonder what the chances are that I have some other beetle than a "true dung beetle". I wouldn't think it matters either way though, the manure is going into the ground, the earth is coming to the surface, and holes are left to hold moisture. I guess I could dig up one of the holes and see if I find the little ball with the egg in it.

Mellifera said...

Dung beetles rock! Speaking of ways to increase topsoil depth and water infiltration... you've got yourself a winner there. I've heard they can get to work pretty fast... maybe just follow a Dexter around until they drop a cow pie and wait a couple minutes to see who shows up to the buffet.

Can I ask what you do for fly and worm control? I've heard that both pesticides and dewormers can keep them from getting established on your land (poop full of Ivermectin isn't so good for grubs it would seem), and even once they're not being used anymore it can take a while for a good population to build up. So I guess I want to check on those statements and/or find out what it is you're doing that works. : )

Rich said...

I found an Australian fact-sheet about dung beetles and one way to sample your manure to estimate your dung beetle populations.

Basically you find some 1-2 day old dung with beetle activity evidence, you shovel up 2 manure pats with about an inch of the soil underneath, then you fill the bucket up with water, stir the dung and soil around in the water, the beetles float to the top and you skim them off.

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