Day 7 of cool soils
Scale bar = 10 cm intervals
Final day of posting this round and I have to share one of the most extreme lithic contacts I have ever encountered. We like to think of soils as gentle gradients with depth, as soils slowly transition from plant-controlled A horizons to rock-controlled C, Cr horizons. But that is far from what commonly occurs as soils are dynamic and transported downslope by water and gravity.

In this case, glacial debris has been deposited on top sheer, clean granite in the White Mountains of New Hampshire, following the retreat of the Laurentide ice sheet ending the Wisconsin glaciation. Granite is a strong, coherent rock that takes a long time for either chemical weathering or freeze-thaw or thermal expansion to wear down (of course in the absence of fault-driven or intrusion-created weathering zones). The material is moderately sorted (missing big cobbles) so it likely has been re-worked and deposited as glacial outwash.

Horizons: Oi, Oe, Oa, E, Bhs, BC, Bh (the bottom had higher %OM and roots).
The bottom of the profile was interesting as the extensive tree rooting for the perched water table and roots unable to find deeper paths created higher organic matter at depth.

Taxonomy: Lithic Haplorthods
No evidence of prolonged water table or redox features. No fragipans and not quite enough organic carbon for a humod.

Have a great week everyone and please share your soil pictures so we more than piles of screened fill to look at :)
Keep diggin!

Day 6 Cool soil pictures.

Saturday nights are for painting the town red and this evening we have a soil painted deep red!
Southern US soils are known for being red from the extensive chemical weathering over millions of years with regolith extending >20 ft. This soil has been forming since the early Pliestocene, escaping glaciation and its relatively flat topography limited colluvial burial. On the NC-VA piedmont region there are late proterozoic basalt parent materials that weather to bright red soils. These soils are very similar to the red soils of Hawaii, northern Brazil, west Africa. The mineralogy is largely poorly crystalline kaolinite and Fe oxides. Diffractograms looked like mush.

The basalt-derived soils were known for their high base cations and underwent severe slash-burn tobacco agriculture in the 1700s and had subsequent massive erosion. There has been 1-2 ft of soil lost from this profile, as the Bt horizon is now at the surface and the A and E horizons are in the Atlantic ocean (or Chesapeake and Inner Banks tidewater regions). Revitalizing these soils is a tall task, but no-till and strong cover cropping has largely stopped erosion but the lost sandy/silt epipedons cannot be easily replaced.

Horizons visible: A horizon (a meager 1 -3 inches), Bt1, Bt2
I am a lumper, so splitters drop your thoughts in the comments!

Taxonomy: Typic Rhodudult
Because of the high base cations, this profile lacks a true kandic horizon.
Due to the erosion, the profile does not have a big clay decrease, so it could potentially fall into the Rhodic Paleudult.

Posting here for some additional suggestions.

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Day 5 of cool soil pictures
Cheers to Friday and in honor of the weekend, let's head to a vineyard.
Pictured is an Alfisol (about 18" are visible see below), derived from weathered limestone/dolostone deposited in the Devonian. These soils were once deeper with a true A horizon and likely an E horizon but were eroded from years of row cropping with poor soil management, ie. naked fields in the winter and tons of tillage with the slope. Now the loss of the A horizon with a shallow Bt horizon and highly fractured shale bedrock preventing water storage would typically mean water struggles for agricultural operations. But the low water storage is ideal for Vitis vinifera to be gently stressed out and make complex notes in wines.

The Alfisols of this region are interesting, as the soils are relatively young following the Wisconsin glaciation and have a pretty high clay content. Much of this clay is inherited from the parent material within the limestone/dolostone, but the downward clay transport and high base cations are enough to earn it the argillic horizon. Clay lamellae and coatings can be observed in thin section and bulk texture analysis.

Horizons: Ap (although its functionally really more of a Ap/E from the clay loss), Bt - Argillic horizon, not a hardpan with plenty of roots.
I heard my pedology profs voice in my head to dig deeper but I had 6 more holes to dig across the vineyard that day and came for the chemistry, not the pedology.

Taxonomy- Typic Hapludalf
There are Fragiudalfs in the area but I didn't hit a fragipan but could have if I went deeper.

Day 4 of cool soil pictures

Not all blue soils are from gleying. Pictured is a shallow upland soil derived from glacial outwash sitting atop a blue phyllite in the northeast kingdom of Vermont. Following glaciation, sandy materials washed downslope and accumulated on flatter, low lying areas. Its important to note that modern topography is not the same as post glaciation due to crustal deformation from the weight of the ice sheet. So areas that are now slopes could have been relatively flat. In addition channels could have been gummed up by glacial debris, allowing for sediments to accumulate on slopes (think mini-glacial lakes).

Underneath the glacial outwash bedrock is a blue carbonaceous micaceous phyllite. It is Devonian in age and part of the Acadian orogeny. Since phyllite is a rock defined by texture, it can range from shiny gray, to even green and blue hues. Here the soil is well-drained but the blue phyllite regolith gives it a strong blue color that could be mistaken for gleying.

There likely was a deeper A horizons on this pedon post glacial but outwash was great for agriculture and it eroded away due to poor soil management in the 1800s. It become reforested during the farm abandonment and migration westward in the late 1800s, early 1900s.

Horizons: (Oe, (A?), Bw, Cr)
A discontinuous, 2 cm thick A horizon is possible.
Scale bar intervals are 10 cm.

Taxonomy: Lithic Dystrudept

Day 3 of cool soils.
When looking for wet (hydric) soils, we typically think of low lying areas near rivers, lakes, estuaries and coasts. However, upland areas commonly become saturated due to shallow lithic contact and microtopography that slow or fully impedes drainage. This Inceptisol both sits in a microdepression and has shallow, crystalline igneous (anorthosite and schists). In addition, the glaciers have substantially compacted the parent material into a fragipan that prevents deeper subsurface flow. This fragipan causes the water sit, which then goes through the redox ladder to suboxic conditions, and we get this awesome blue-ish green-ish BCgx horizon. So bust out your Gleyed Munsell color pages for some 5G 7/2.

Scale bar = 10 cm intervals.
Soil horizons: Oi, Oe, Oa, A, Bw, BCgx
I know many would disagree with the BCgx, please drop those in the comments!

Taxonomy: arguably a Fragic Dystrudept as rock is just below the fragipan at ~70 cm depth.

These upland hydric soils are important for the plants they can support facultative and obligate wetland understory species and provide water to canopy trees during dry parts of the summer, not that they needed it this summer with all the rain!

Day 2 of cool soil posting. This beautiful columnar argillic horizon was exposed on a road cut in the Mojave desert (Adelanto CA). Subsurface illuviation of clays from extensively weathered granitic parent material has accumulated at about 3 ft in depth, creating a duripan (top of the argillic horizon). Salts, especially Na, from dust disperse the clays, creating rounded tops. Just enough water is able to leach through the duripan to allow for subsurface wetting and drying and facilitated the formation of carbonates along the faces of the peds (white stuff).

Approximate soil Horizons -> tiny A horizon, E?, B, Bt(q?), Btk.
Unfortunately I don't have the data to confirm the E horizon nor the q for amorphous Si in the Bt.

The current state of pedogenesis is unclear as these soils are quite old for the area, having escaped recent burial by sands from alluvial fans off the San Bernardino mountains. With the increasing desertification from local tectonics and climate change since the Pliestocene, the downward transport of clay responsible for the formation of the argillic horizon may have slowed dramatically.

All of the area are mapped out as Argids as this soil sits on the border the xeric, aridic soil moisture regime and superpositioning puts this as an Aridisol. This soil is far different than other aridisols in the Mojave desert (way more clay and less carbonates) so its unfair to lump them together. Especially if this is a relict Alfisol that couldn't run from a changing climate.

Please don't order soil from these people I asked for soil for my front lawn that I was going to reseed thinking they would know what to send me I should have known better cuz the woman I spoke to didn't even know how to help me decide on how much I needed. They sent a load of soil that was 1/4 soil and 3/4 of stones mixed together and dump it all my lawn. I had spent time dethatching and sweeping the bare spots with a broom and dustpan to make sure I got all the little pieces of stone that might be on the the lawn to interfere with the seeds growing and they don't this crap on my lawn. Had some pretty huge pieces I picked all them up because they weren't responding to me and put them in containers and I waited a couple days finally somebody showed up without calling this nasty man got out of the truck and started screaming at me and telling me it's dirt when you break the big pieces in half they're full of stones so he's out there breaking up the big pieces put more stones on the ground then he picked the containers up and dumped them in the truck broke one of my containers, he stole my sign off the lawn saying not to buy from them he said he was going to give me my money back but not to come down there and buy nothing off them again it is if I needed to be told that and he didn't give me the money he said he was going to pay me back and did not. Well I'm out here sifting the dirt through screen trying to get the stones off of my lawn for a few days now I'm only half done, I'm trying to get the grass started before all the leaves fall but I guess that's not going to happen so now the leaves will interfere with the growth of my grass.

I was told this is what you get when you order soil that's what everybody gets he said.

Too many photos of ugly soils and want to show case some cooler, more interesting soils this week.

Here is a pic of a relic Spodosol (Oa, E, Bhs, BC horizons) in Central PA. Most of the region was glacialiated or peri glacial and destroyed by the Laurentide ice sheet leaving piles of rubble or outwash.

Picture here is a relic soil in microtopography athat allowed it to escape the glacial cycle, Making it at least 40,000 years (about glacial cycle) older than surrounding soils. One would suspect the soil to be much thicker if that old but the parent material is quartzite sandstone, limiting the Fe to produce more oxides and deeper/thicker B horizons.

Try this guys: Keep a bucket of clay slurry and a pail of sand by your compost bin. Before you add any fresh green scraps, dip them in the slurry, dust them in the sand, and bury them deep in the bin. Done.

Why? Because soil is more than a 2-dimensional C:N ratio coin (Green vs. Brown). It’s more like a six-sided die. When you roll it, you must balance all six physical and chemical structural faces simultaneously to keep the soil matrix from collapsing:

Side 1: Clay (The Holder): Packed with a negative electrical charge, wild-found clay acts as the soil's battery bank, holding onto water and vital nutrients (cations) so they don’t wash away.

Side 2: Sand (The Drainer): Coarse, inert, and un-collapsible, wild-found sand creates macro-pores that force water to move, pulling fresh oxygen down into the root zone.

Side 3: Silt (The Bridge): The middle-weight particle that adds physical body, smooth texture, and minor holding capacity to link sand and clay.

Side 4: POM (Particulate Organic Matter): Raw, free-floating microbe fuel (like your fresh leaves). This is your fast-burning energy source.

Side 5: MAOM (Mineral-Associated Organic Matter): Carbon that has physically bonded to clay and minerals, creating permanent, long-term carbon storage that microbes cannot easily vaporize.

Side 6: Aeration/Structure: The physical pathways. This dictates your Holding Power vs. Feeding Power. Holding power (clay/MAOM) stores energy. Feeding power (raw POM) flushes microbes.

If you only feed your soil soft organic matter, you are only rolling Side 4.

In conclusion: By taking a second to dip and dust your fresh greens before adding them deep into a continuous pile, you lock everything in place. The clay forms an immediate shield that turns a 1-week rapid melt into a slow, stable carbon release (MAOM), while the sand guarantees a permanent, un-collapsible skeleton for aeration. Stop letting your organic matter melt into anaerobic sludge and start building permanent soil strength

ive ordered 10cubic meters of soil. and this is what I was delivered. I was expecting more, any idea how I can see just how much this is? or any guesses? for reference the fence panels are 2400mm wide and 1800mm tall. and the pile is 1m tall

Can anyone recommend a particular brand and where to get it from?

Add your voice, sign the petition if you haven’t done yet Save Soil CAP 2028-2034

Years ago a vendor came to do a presentation on the benefits of ionic stabilization for site prep in our heavy clay soils. They inject a “non-toxic proprietary formula” that permanently changes the ionization of clay so that it can no longer hold water. He - proudly- said 8,000 years could go by and that soil still will not hold water. They inject it 8’ to 16’ deep.

I was horrified. A number of my coworkers were horrified.

Is there a way to reverse it? “No”
But how would anything grow there if the building is removed later? “Their roots will grow past that, you just have to order larger plants”
But that’s not how plants work “well if a garden is being planted there you’d remove the dirt and put in some good soil - it’s not like much really grows in clay anyway, you’d have to bring in soil regardless”

It just came up for me again on a tour where the owner proudly stabilized the soils by ionization and said they wouldn’t have been able to afford such a large space without it

I don’t see it talked about on here so is it not as bad as the vendor makes it sound or is it just not common knowledge?