The size of it
From cores of soil, each about a teaspoon
They came from kinds of plant in marker genes, at – DNA reads a core, from one patch of ground, sampled once.
Before anything else: every number here counts DNA, not bodies and not activity. Dormant microbes leave DNA behind; so do dead ones, until it decays — and in soil the dead share is large.
What the DNA showed
The plant above picks the neighbours below
Every patch holds about the same amount of life, whichever plant is growing over it (p = ). Which organisms are there is a different answer: the cores group by the plant above them, by more than chance produces at this sample size (p = ). Plants shaping the community beneath them is well documented, in soils far beyond this one — so this is a pattern the field shares with pasture everywhere, seen here in detail.
Each dot is one pair of cores. The gap is real on average, and there is a great deal of overlap. The bar is the average, the whisker its 95% interval.
It is a food web, not a soup
A second marker gene picks up the organisms with more complex cells: fungi, protists that hunt and eat bacteria, and the microscopic animals that eat the protists. Something is eating something else down there, which is more than a list of residents sharing space.
The complex-celled share of this soil, across cores. "Other" is everything the reference database could not place, which in soil is never small.
And one number this study cannot explain
Turning ammonia into nitrate is one of soil's essential jobs, and here it is dominated by archaea — an ancient branch of life, separate from bacteria — to a degree that in farmed soil usually points at one thing: very little nitrogen going in. The study tested that reading against its own data, and it did not hold. The number and the test that undoes it are both on the research page.
What this does not establish
Thirteen cores from one field, sampled once, cannot carry much. What to know before quoting anything above.
- Why the archaea dominate. The tidy explanation was tested against every other common organism in the same soil and ranked of — unrelated groups track the archaea about as closely. So something is moving all of them together, and it is not the explanation we started with.
- Anything at all about how the farm is run. This is the biggest one, and for a while this site got it wrong. Every core came from one weedy patch. There is no second field, no comparison, and nothing in the records that even says how the ground was managed — so no result here can be credited to farming, good or bad. The one published study that sampled pastures this way found no difference between organic and conventional management within itself (p = ), which is a useful warning about how easily that kind of claim is made.
- That grazing animals are not behind it. Cattle drop nitrogen in patches, and nitrogen is exactly what the archaeal result is read against. Whether stock reach this particular patch was never written down, so it cannot be ruled out — and it cannot be waved away by calling the patch untouched either, because that was never established.
- That the soil is not simply acid. Acidity drives the same balance, and this soil's pH has never been measured — only mapped. The study argues from which kind of archaea turned up, which weakens that rival explanation without replacing a pH meter.
- Anything about rates. Every functional statement here is about which organisms are present and in what proportion. A gene that is present may be switched off. Nitrogen cycling was never watched happening in this soil.
- Anything about white clover. Only one core was taken under it, which is not a group.
- That being unploughed makes it special. An independent land-cover record puts this ground in pasture or hay every one of years, never once tilled — which rules out the most disruptive thing that can happen to a soil. Most long-standing pasture can say the same, though. And that record is drawn at a resolution coarser than the patch itself, so strictly it describes the ground around where the cores came from.
Every abundant group of bacteria in this soil, placed by how closely it tracks the archaea. If the proposed explanation were the right one, the orange marks would be alone at the left. Instead they are somewhere in the middle of the pack.
What this adds up to is a baseline: a close description of the soil life under five plants growing side by side, in one patch of ground on one day. Of the two real patterns in it, the plant shaping the community beneath it is something soils do everywhere — but it is worth knowing it happens between a weed and the grass next to it, over a few metres, on the same soil. The archaeal number is still unexplained. Tying either of them to the way this ground is farmed would take a different study, and one this design cannot become.
Where to go from here
Research
The whole argument: the census, what separates the patches, the headline number, the obvious objection to it, and the test it fails.
Methods
How each number was computed, which checks came back negative, and what is not documented — including the lab work nobody wrote down.
Sources
Every external work this study stands on — the software, the databases, the primers, the tests — and what each one was used for.