Coarse fragments

Cool Btkn horizon - columnar structure

Heating alone won’t drive soil microbes to release more carbon dioxide — they need added carbon and nutrients to thrive. This finding challenges assumptions about how climate warming influences soil emissions.

cross-posted from: https://slrpnk.net/post/27610583

• Tropical forests exchange more CO2 with the atmosphere than any other terrestrial biome, meaning that even a relatively small shift in the balance of carbon uptake and release there could have a big impact on global climate. Despite this, research on tropical soil responses to warming has lagged behind.
• In a field experiment in Puerto Rico, researchers used infrared heaters to warm understory plants and topsoil by 4° Celsius. Warming significantly increased soil carbon emissions, but terrain also had a major impact: A warmed plot at the top of a slope showed an unprecedented 204% increase in CO2 emissions after one year.
• Carbon emissions from plots lower on the slope increased between 42% and 59% in response to warming — in line with the results from the only other long-term tropical soil warming experiment to date. However, the upper-slope response represents the largest change in any soil warming experiment conducted globally.
• The new study results add to a growing body of evidence that tropical soils are far more sensitive to warming than previously thought. If elevated tropical soil CO2 releases persist in the long term, it could have dire consequences for Earth’s climate. But the soil biome may adjust over time, so future effects remain unclear.

archived (Wayback Machine):

• Mongabay article
• research cited

• Earth’s top 2 meters (6 feet) of soil hold 2.5 trillion metric tons of carbon — more than is held in living vegetation and the atmosphere combined. But soil carbon sinks are under threat — global warming could trigger a positive feedback loop that seriously accelerates soil emissions, just as we take steps to decarbonize society.
• The effects of elevated temperature and atmospheric CO₂ on soil carbon have been factored into climate models. But those models don’t currently capture the true complexity of the soil carbon sink, in part because scientists don’t fully understand the mechanisms that influence soil carbon gains and losses.
• Major knowledge gaps urgently need to be addressed: How are long-term soil carbon stores protected from microbial consumption (and CO₂ release)? And how will global warming alter microbial communities, deep soil carbon, and the climate sensitivity of tropical soils (which store a third of global soil carbon)?
• Improved understanding of soil carbon dynamics could offer an opportunity to better manage agricultural and forest soils for carbon sequestration. With proper management, degraded soils could sequester a billion tons of additional carbon annually, making them a key ally in the fight against climate change.

archived (Wayback Machine)

I'm not up to snuff on my USDA taxonomy, but here is an explanation of this horizon:

• Soils consist of three master horizons: A, B and C
• this soil is from the B horizon
• two nearly mutually exclusive pedogenic processes have occured to create this horizon:

1. Illuviation - the deposition of clays from the A horizon
2. Carbonate enrichment

Clays and carbonates both leach from the A horizon during pedogenesis, but carbonates move way faster and are long gone before the first clay particles arrive. Clays move much slower and don't go as far.

You can get carbonate enrichment from deeper in the profile though capillary rise, but it's almost always restricted to the C horizon. What you end up with is a very rich carbonate layer over top of the naturally calcareous layer of the soil.

In THIS case, evaporation is so strong it's brought these carbonates into the B (middle) horizon so you end up with a calcareous, clay enriched B horizon which really should not exist.

Soils are wild.

Bonus picture

I'm doing mainly hydroponics by now, but still have some pots on my balcony with soil in them, and I don't plan to change that.
Most of them are just "there" and filled with flower mixes for insects, aka weeds.
Those aren't high value crops for me, but still, I'm seeing them as test subjects.

The soil is mostly highly organic and I built it up myself from scratch.
A big portion of it is actually mushroom mycelium blocks, aka decomposed hardwood and millet, with some rock meal, LECA and compost on top.
Maybe that information is relevant, idk.

I pay a lot of attention to the biological activity, e.g. earthworms and springtails. There seems to be lots of decomposition happening.

The pots are already in use for at least one year, and I've always watered them with tap water.

Now, the blackberries, growing in one of my oldest pots, the only one with a high clay content, is showing signs of a deficiency, even though I put more than enough organic fertiliser in it last year.

I suspect it's because of my watering habits. My tap water doesn't contain any chlorine or other harmful stuff, but still, lots of Calcium, Magnesium and carbonates. It has a high pH, sometimes reaching even 8+!

The plants are thirsty and need lots of it, so I just wanna know how bad it really is.

I know that the availability of nutrients is depending on pH and other ions, but does it really matter in soil?

Last year, when I made a new batch, my soil was contaminated with something highly alkaline, and the drain off pH has been 10+ for some time, but still, the plants coped very well with it and didn't show much signs of deficiencies.
It's now in the 8-ish range, but I can't say it for sure because my testing methods are shit, see my other post.

Does it have something to do with the microbes living in it?

Pictures

I have a few pots of soil I made myself on my balcony, and I wanna test following things:

• pH: I already have a pH testing rod for soil, but it seems to be very inaccurate.
  I also have a proper digital pH meter for my hydroponics, which is way more accurate. How do I test the soil in the liquid form? Are there any standards, so it is more comparable?
• Composition: Ratio of organic vs inorganic stuff, and also the water retention and aeration.
• Microbial and biological fingerprint: I saw a huge amount of earthworms last year, but this year, none at all. Did my ants kill them? Are they still there, but just beneath the soil?
  How well do the microbes feel? How active is the soil?
• Decomposition grade (I'm reusing the soil from the last years): how drained and compacted is my soil already?
• Are there harmful nematodes or whatever in there?
• The ratio of Calcium and Magnesium compared to other ions (I suspect nutrient lockouts due to tap water)
• etc.

As a background, I'm a "chemist" and also have some skills, chemicals and equipment average people may not have.

Here are some pictures :)

The blackberry with deficiencies:

And some pics of dirt from different pots. The top layer may look different than the what's below.

Urbanization is reshaping soil microbial communities worldwide, driving an unexpected homogenization of bacterial populations while fungal communities remain more resistant to change.

A new study warns that global declines in soil moisture over the 21st century could mark a “permanent” shift in the world’s water cycle.

cross-posted from: https://slrpnk.net/post/19458072

A new study published in Ecological Processes by researchers at the Institute of Applied Ecology of the Chinese Academy of Sciences reveals that no-tillage (NT) farming could play a pivotal role in combating soil degradation and enhancing carbon sequestration in arid and semi-arid regions.

I had a really bad slug infestation on my balcony garden last year. Because they were eating on everything, and were in the thousands almost, I had to resort to "poison" bait. Not one of the toxic ones, because I have cats, but ones based on Iron phosphate.

Still, it resulted in another pest: all those slimy slugs crawled under the floor cover and died there. Disgusting. Everything was full of flies and stank.
But mainly, it was mentally horrifying.

This year, I want to do it differently. Instead of killing them, I want prevention.

I already looked up online, but all "natural predators" are bigger ones, like ducks and toads, but of course that isn't viable on my small balcony.

So, I thought about already killing them in the egg stage.

What natural killers, like nematodes or bugs, do they have in this life stage?
What can I do to attract them?
How is that regulared by natural balance?

Anyway, I got outside and dug up some soil samples from different locations and spreaded them in the pots, hoping that there are some eggs or critters in there that are currently hibernating and then improve the natural balance in the summer.
It was only one hand full of dirt per big pot, but that should be enough I believe. It's only the catalyst/ starter culture after all.

Btw, I'm currently building up the soil for the following season. Last year has been absolutely great with organic living soil, and I want to improve on that.

The new soil, consisting of spent mushroom blocks, some soil, leaf matter, and more:

And the old one from a few months ago, when I harvested my hemp tree:

I plan to reuse it of course! No-till, a shit ton of organic matter, very well aerated with deep roots from the decaying plant that was previously in there. Extremely healthy dirt 🤌👌

Some pedologists like to split out every little detail when classifying a soil profile. Others? Not so much....

Pedologists are a prickly bunch; tons of strong opinions, so lumpers and Splitters have some epic arguments

To understand what might be lost, ecologist Janet K. Jansson taps molecular methods to explore Earth’s underground microbes, from the permafrost to the grasslands