Soil Structure Pic

[oze]

Following the instructions from this article http://aroundtheyard.com/home1/articles ... ement.html, I pulled a couple of 4" cores from my water-repellant back yard. A picture of what it looks like after 2 days is attached (ignore the green marks--squiggly purple is correct in this case).



So Andy, will you take that $5 as an additional donation to the site? I know that this is not definitive and now, more than ever, I want to include a soil analysis request when I send in my sample to Logan Labs in the spring. On the other hand, I am gobsmacked to see such a small percentage of clay in my sample. Surely, I must have screwed up something, right? How can I have so much sand/gravel and silt and have such impermeable soil? Does silt compact this much?

I know that nothing can nor should be done about it now, and will of course wait for the 3+ year plan that the site experts recommend after I post my results from Logan next year, but if anyone has any comments just to settle my curiosity and confusion, I would appreciate it. Thanks.

[andy10917]

I'd call that 45/50/5 at best. Typical of the area.

All lost bests are paid to the "Donate" button at the bottom of the page.

[oze]

I'd call that 45/50/5 at best. Typical of the area.

All lost bests are paid to the "Donate" button at the bottom of the page.

PayPal, here I come. Thanks, Andy!

Oh, and feel free to add my case to your future article "No, you do not have clay soil"!

[HoosierLawnGnome]

Looks pretty typical - here's my soil structure test from Logan's -

[oze]

Thanks, Hoosier. This is yet another indication of just how much I need to learn about soil. As my wife (the gardener) asked when I showed her the tiny percentage of clay in our soil, "Then why can I mold a little clay animal from the soil I dig up 4" down from my garden?" I was feeling the same way--it feels like the stuff I used in kindergarten to make my dad an ashtray. And don't these results indicate that we have almost ideal soil, at least in terms of structure? I plotted my results on the Soil Structure Triangle, and it indicates that my soil is right near the intersection of sandy loam, loam and silt loam. And that is just hard for me to believe.

[rtomek]

Your soil is very dense and has lots of silt in it, which can make it seem like a clay body. Clay bodies used for e.g. pottery may only contain a small fraction of clay, as well. The clay bodies are simply sifted soils such that you remove much of the sand and other large particles, while geological clay has a specific mineral structure and chemical properties.

[HoosierLawnGnome]

Yeah, like rtomek said - it is really dense.

My soil is VERY dense. It needs regular watering and soil conditioner. Once it dries out - say day 5 of no rain - it will start getting dusty then crack.

When water pools on some areas, it is this muddy, soupy mess. Those area are then the worst to really tighten up when it dries out - like concrete. I can drive my SUV over those spots and see no indentation when they're dry. It's like two extremes on those spots - hard to keep in the middle.

The main thing for me is preventing pooling on those trouble spots. Then I can control moisture from there.

I cant' go a whole week without some moisture though - in the full sun areas the soil gets dusty and cracks too quickly.

[HoosierLawnGnome]

And don't these results indicate that we have almost ideal soil, at least in terms of structure?

Well, get a soil test from Logan when the ground thaws out this coming spring - that'll tell you.

You are a lot further north than me, but what I've found is that newer subdivision - type soils in the Indy area are similar to mine - high pH, high Calcium, low Organic Matter, low Potassium / Phosphorus...

But you just don't know until you test - there's such a variety of conditions. I can think of a few members in older areas of the city that have better soil - probably because they've had trees adding OM for 50 years and didn't have the top soil scraped off by the heavy equipment used in their construction techniques.

[oze]

And don't these results indicate that we have almost ideal soil, at least in terms of structure?

Well, get a soil test from Logan when the ground thaws out this coming spring - that'll tell you.

You are a lot further north than me, but what I've found is that newer subdivision - type soils in the Indy area are similar to mine - high pH, high Calcium, low Organic Matter, low Potassium / Phosphorus...

But you just don't know until you test - there's such a variety of conditions. I can think of a few members in older areas of the city that have better soil - probably because they've had trees adding OM for 50 years and didn't have the top soil scraped off by the heavy equipment used in their construction techniques.

Oh, I absolutely plan on the full test from Logan come spring. I'm a a newish (20 year-old) subdivision without a lot of trees, so I know my work is cut out for me wrt soil modification.

[oze]

Your soil is very dense and has lots of silt in it, which can make it seem like a clay body. Clay bodies used for e.g. pottery may only contain a small fraction of clay, as well. The clay bodies are simply sifted soils such that you remove much of the sand and other large particles, while geological clay has a specific mineral structure and chemical properties.

That is very interesting, thanks, rtomek! It appears that what lay people, such as myself, call "clay" isn't clay at all, geologically speaking. But it sure does behave like what I picture when I think, "clay".

[oze]

Your soil is very dense and has lots of silt in it, which can make it seem like a clay body. Clay bodies used for e.g. pottery may only contain a small fraction of clay, as well. The clay bodies are simply sifted soils such that you remove much of the sand and other large particles, while geological clay has a specific mineral structure and chemical properties.

Very dense indeed. I just finished the soil percolation test--water drained a little over 1/4" in an hour. Yikes.

[rtomek]

But, remember you DO have a good soil! Since it is dense, that means it can hold a lot of nutrients (and water) for your grass. You may be able to improve the water infiltration, just consider this your starting point.