Guest post by Henry Gillard
[This originally arrived as a tip/suggestion for a post. The author was encouraged to turn it into a complete post. Be gentle~cr ]
I loathe reading scientific papers. Too often the grammar is appalling; the objectives of the work being described are unclear; the main body of the paper is a thicket of technical terminology; the summary of what has been found is unintelligible (and sometimes, the summary seems hardly related to the body of the paper).
Occasionally, just occasionally, I read something in a scientific paper that makes me smile. It has a ring of truth, expressed in clear language. I came across just such a statement yesterday, and I feel the need to share it with a wider audience.
It started with a typically breathless, alarmist warning from Stanford University:
“Stanford research finds that when elevated carbon dioxide levels drive increased plant growth, it takes a surprisingly steep toll on another big carbon sink: the soil.”
The claim is in a 29-03-2021 report; https://news.stanford.edu/2021/03/24/one-earths-biggest-carbon-sinks-overestimated/?utm_source=Stanford+Report&utm_campaign=1a26a66d1f-EMAIL_CAMPAIGN_2021_03_26_03_17&utm_medium=email&utm_term=0_29ce9f751e-1a26a66d1f-53979409;
The report summarises a paper published earlier in the week (24-03-2021) in Nature, and adds comments from two of the co-authors.
The lead author lets us into one of his secrets: “When plants increase biomass, usually there is a decrease in soil carbon storage”.
Wow! Who would have thought that? When a plant grows, it extracts nutrients and carbon from the soil and converts that into its roots and stem and flowers and seeds. That sounds like something I learned at age 11 in Mr Collins’s Biology class, but Mr Collins was not a Fellow at Lawrence Livermore National Laboratory who worked on this research as a post-doctoral scholar at Stanford University, so perhaps I under-rated him all those years ago.
The senior study author – who is both the Michelle and Kevin Douglas Provostial (whatever that is) Professor at Stanford’s School of Earth, Energy & Environmental Sciences, and also a Senior Fellow at the Stanford Woods Institute for the Environment – confides: “It proved much harder than expected to increase both plant growth and soil carbon.” At this point it would have been helpful if he had given us an insight into his theory of how the plant interacts with the air and the soil, and what he expected to happen. But he didn’t. See my initial grumpy remarks, above, about failure to state objectives.
Despairing of illumination from the Stanford report, I followed the link, https://www.nature.com/articles/s41586-021-03306-8 , to the original Nature article. Let me quote the entire Abstract, verbatim other than for removal of the references. Read it slowly and savour it.
Abstract
Terrestrial ecosystems remove about 30 per cent of the carbon dioxide (CO2) emitted by human activities each year, yet the persistence of this carbon sink depends partly on how plant biomass and soil organic carbon (SOC) stocks respond to future increases in atmospheric CO2 . Although plant biomass often increases in elevated CO2 (eCO2) experiments. SOC has been observed to increase, remain unchanged or even decline. The mechanisms that drive this variation across experiments remain poorly understood, creating uncertainty in climate projections. Here we synthesized data from 108 eCO2 experiments and found that the effect of eCO2 on SOC stocks is best explained by a negative relationship with plant biomass: when plant biomass is strongly stimulated by eCO2, SOC storage declines; conversely, when biomass is weakly stimulated, SOC storage increases. This trade-off appears to be related to plant nutrient acquisition, in which plants increase their biomass by mining the soil for nutrients, which decreases SOC storage. We found that, overall, SOC stocks increase with eCO2 in grasslands (8 ± 2 per cent) but not in forests (0 ± 2 per cent), even though plant biomass in grasslands increase less (9 ± 3 per cent) than in forests (23 ± 2 per cent). Ecosystem models do not reproduce this trade-off, which implies that projections of SOC may need to be revised.
I find it beautifully droll to read: “(From) increases in elevated CO2 (eCO2) experiments, SOC (soil organic carbon) has been observed to increase, remain unchanged or even decline. The mechanisms that drive this variation across experiments remain poorly understood.”
Oops. They let the cat out of the bag, there! I can almost hear them saying, “we’ve got these prestigious jobs, and we’re paid all this money, and we’ve done all this work, but we don’t understand what’s going on”. Maybe I’m being cynical, but I really do wonder if that is going to be their justification for asking for more grants to do more work. Either way, I got a smile out of that, and I hope you did too.
Seriously, what concerns me most is that the authors seem to be drawn to a crude causal relationship between the concentration of eCO2 and the change in SOC, in which the former affects the latter through the mechanism of plants “mining the soil for nutrients”. It really is a shame that they have not made explicit their understanding of how eCO2, SOC and the plants interact, both over a single growing season and over an extended period. The crucial failing in their model (if we may accord it such an honorific) is that it does not attempt to explain how the SOC can rise at all when plants are growing. Mere correlation does not signify causation. And “increase, remain unchanged or even decline” does not even signify correlation.
My interpretation of that interaction – based on the notes that I made in Arthur Collins’s Biology class 1965 – is:
- high eCO2 initially stimulates plant growth;
- plants take in CO2 from the air to build their (carbon-based) biomass;
- the healthy, growing plants take in SOC (soil organic carbon) for the same purpose;
- hence the SOC concentration falls;
- as the nutrients are depleted a plant’s growth slows, so there is less need for the plant to extract further SOC from the soil;
- when plants die, they decay and their constituents become part of the soil.
The corollary of falling SOC concentration – all other things being equal – is that there is more capacity in the soil to absorb more CO2 in the future, by the same mechanisms that have existed since time immemorial.
Looking at their figures: With elevated eCO2:
- SOC stocks increase in grasslands by 8 ± 2 per cent
- SOC stocks increase in forests by 0 ± 2 per cent
- plant biomass increases in grasslands by 9 ± 3 per cent
- plant biomass increases in forests by 23 ± 2 per cent
On my interpretation:
- Grasslands don’t build the biomass as efficiently as forests
- Grassland biomass increases by 9%: the process stimulates initial SOC depletion and subsequent replenishment by nett 8%
- Forest biomass increases by 23%: the process stimulates initial SOC depletion and subsequent replenishment by nett 0%
On the study’s figures, planting an acre of trees will absorb more CO2 than will be absorbed by planting an acre of corn. Crucially, over the timeframe of the study, the forests tend to leave the SOC concentration unchanged, while the grasslands increase it. If we look at the sum of biomass increase + SOC increase for grasslands, compared to that for forests, they are not that different: 8+9 as against 23+0. Is that surprising? Not to me. If there were a huge difference then I suspect that the one that performs better would have colonised the other one completely, over the course of the earth’s existence.
The Nature paper and the Stanford report on it do not concern themselves with what happens over decades. Their key view seems short-term: “when plant biomass is strongly stimulated by eCO2, SOC storage declines; conversely, when biomass is weakly stimulated, SOC storage increases” ie if there is lots of extra CO2 in the air, then the SOC will fall because the plants are growing strongly, and if there is just a little extra CO2 in the air the plants don’t grow as strongly so the SOC rises rather than falls.
Moreover, the authors have an implicit belief that extracting SOC from the soil is self-evidently bad, because they fail to see the benefits in converting SOC into extra wheat, rice and other crops to feed a growing world population. But let’s not get sucked off-topic.
So, does this mean that planting trees to reduce CO2 is a waste of time and money?
Well, if you think climate alarmism is baseless, then your answer is bound to be ‘yes’, so let me ask the question only to those who believe there is any merit in lowering atmospheric CO2.
Look at the paper; look at the numbers. Make up your own mind. I’m not going to tell you what to think.
If you think the concerns in the paper are valid, then ask yourself what you are going to do. Write to your local mayor and tell him to stop wasting public money on his virtue-signalling tree planting initiative? (Every town seems to have such a scheme). And are you going to risk incurring the wrath of the Greens and the hippies and the media? They may not be amenable to persuasion by this paper.
Or if you think the report has questionable methodology, is poorly written, and has unconvincing conclusions, then are you doing to write to Stanford University and ask them to not waste their money giving another grant to these people?
Or will you do nothing?
Seems like the real purpose of the article discussed is damage control and trying to reframe the discussion – trying to spin the 15% or more greening of the world in just past few decades of the satellite era, as something bad. Almost all science articles are drenched in climate re-education propaganda these days and are reaching the nauseating level of stupidity and grasping-at-straws level of desperation in trying to make rising co2 levels a bad thing.
Can’t the richest soils be found in Sahara? Q.E.D.
” trying to spin the 15% or more greening of the world in just past few decades of the satellite era, as something bad.”
Did new forest growth spark a mass extinction 360 million years ago? (msn.com)
The plants are killing the soil and now they’re gunna kill the oceans. Doomed they tell ya. You’re all doomed! Only more grants can save ya now.
As a farm kid raised tilling the soil before planting, I am appalled that these “educated idiots” think plants take carbon from the soil. They take nutrients from the soil and ALL the carbon comes in from the air, thru the stomata in the leaf. All the carbon coming from the soil is released from the rotting plant matter in the ground, that is exposed by tilling the soil before planting, or from rotting vegetation brought to the surface by that tillage.
Rising CO2 levels have reduced the area of the Sahara desert by 700,000 square kilometers since we have satellite photos to measure it by. CO2 is plant food, NOT a green house gas. Humans contribute 3.5 % of the CO2 in the atmosphere, and plants take damn near ALL of it back out each year!
There was an experiment done in the 1950’s by the Ag Dept, and they found a growing field of corn, “stopped growing by noon, if there was NO wind to bring more CO2 into the field. Yes you saw that right. The field absorbed ALL the CO2 released overnight by the soil, by noon, and needed more from outside to keep growing.
Back in the dark ages you couldn’t publish much that restated what was known or intuitively obvious. Now the science seems to need regular doses of in elevated CO2 plants deplete soil nutrients and carbon. Wasn’t plant growth depleting the soil the reason we started fertilizing crops long, long ago?
And therein lies a deep wisdom: Modern agriculture “replenishes the soil” with Potasium, Phosphorous and Nitrogen, which is proven to destroy the (carbonaceous) microbial soil biosphere, leading to ever-increasing loss of nutrition in our food crops.
Like with weather modification technology, the climastrologists never mention the corporocratic interference in our biosphere, the deliberate disequilibrium perpetrated in the name of “sustainable economic growth”.
Do you think they do this to (1) hide these corporate crimes against humanity (and nature), or are they (2) just ignorant of the real-world realities of industrial-scale biocide?
I think “their betters” are doing the first by taking advantage of the second…
Ridiculous! Nonsense!
Please review your soil chemistry (if you have got any) and find that the effect of compound fertilizers has nothing to do with microbial life and everything to do with the vertical movement of minerals in the soil solution (towards out of the soil profile and eventually leaking away downstream): its a quick physico-chemical processess, not a biological one. It takes differents rates and forms according to the physical and chemical composition of each soil (kind of clays, granulometric distribution, etc.) AND according to the timing of incorporation of fertilizers AND with the prevailing temperature (mainly) AND of course with the kind of plants that live there (grasses of what kind, trees; natural grasslands or cultivated pastures; forests or fruit orchards).
Please don’t talk about “biocide” before you know what life is and means, and don’t talk about production processess whose technology you obviously d’ont know and eventually cannot understand.
“proven to destroy the (carbonaceous) microbial soil biosphere”.
Given your contention that this is “proven” then surely you could elaborate on the mechanism, or provide a link to such an explanation, as it seems a bit fantastical.
Other than a group of words that sound nice together, what does “microbial soil biosphere” mean? Similarly why do you qualify the microbial community as (carbonaceous) – is there a non-carbonaceous community we should be aware of? Perhaps silicone based?
There are many examples of poor agricultural practices degrading soils but your post suggests you lack even a basic knowledge of the subject.
Soil microbes tend to have “shells” made of silicates.
Someone actually ‘weighed’ microbial life in good topsoil, I dysremember the figures, but I think it was around 17 tons per hectare. Similar soil under “sustainable” chemical fertiliser protocol weighed out at about 4 tons/hectare.
In any complex organism, animal, human, hive, landscape, marine, the microbial life not only feeds and maintains the greater organism, it often outweighs the organic matter of the organism itself.
Okay then. Let me just get the sticky juice off my fingers before I answer you, I’ve been munching on fresh, wild berries I harvested this morning from my own no-till, organically (poop/compost) fertilised non-hybrid,heritage strain, non-GMO and non-poison mix-crop vegetable garden. (The fences are not wire, not safe for the horses, so I plant hedges, with berries and herbs and various medicinal plants and brewing gruit plants.
To be fair, the no-poison thing is still costing me in lost harvest, but we get better every season. I had record peaches and pears this year, but excessive rains cost me grapes, figs, and apples galore.
So, no, I know very little about being a farmer, I just try feed my own…without poisoning them. For that, I had to research quite a bit about soil biology, and mostly ignored soil chemistry, choosing suitable plants for the soil, not “fixing” the soil for luxury
cracrops.https://greenpets.co.za/index.php/en/greenpets-herbal/83-the-greenpets-herbal
The old “I raise a tiny garden” claim to advanced agriculture knowledge…
That is a misleading statement because it is the DOSE of a chemical that matters here, excessive nitrogen for prolonged periods of time does damage the population of microbes in the soil, but that is a well know problem that has largely been accounted for in recent decades.
Secondly growing HYBRID crops for years can drain some soils as they require a larger share (sometimes a LOT more) of elements from the soil than open pollinated varieties do which is why they should be doing to fallow farming to allow it to restock the elements that gets drained to a low level.
There are other factors not commonly considered, such as excessive bad plowing which slowly or rapidly destroy soil TILTH ability to breathe and hold elements in place:
Soil science is a college level subject that farmers have degrees in for this very reason, to maintain and improve the soils they own or go bankrupt.
Pure insulated urbanite delusions.
All plants need nitrogen, potassium, calcium, magnesium, phosphorous, sulfur, chlorine, iron manganese’s, boron, Zinc, copper, molybdenum and nickel to grow. The plant takes what it needs and then the animals and bacteria take what they need andante excess runs off. If you are short just one nutrient nothing will grow. Apply too much and you can kill the plant the bacteria, and any animals or insects in the soil. If you get it right everything, plant, animal, and bacteria will grow. Most farmers apply only those nutrient the runout the sickest. Mainly, NPK. Most seldom apply and iron, zinc, copper boron. Since they cannot accurately predict how much is needed they often apply more than needed.
IN short fertilizers are not a biocide in any way. However overdosing or underusing or incomplete nutrient applicationis bad. But there is no easy way for a farmer to get the fertilizer dose exactly right. But if you grass clippings and and other manure you are more likely to get all the nutrients need. But at a higher cost of labor and materials.
until we started monocropping and removed mixed farms with animals who ate n pooped the majority of the soil gained nutrients back in faster assimilable forms..we didnt NEED chem fertilisers..
poop went back for worms animals ate weeds as well as grass n crop wastes dung beetles contibuted oxgen water infiltration n deep manuring as well
then we listened to the big aggro “experts needing a use for chem wastes after WW2 and it all went to hell
see The Albrecht Papers multiple volumes
… “and it all went to hell” ??? Ending famine is “and it all went to hell”? How is the Western population suffering from malnutrition when we’re actually getting more obese and taller? If you prefer so-called organic food over regular produce then enjoy the freedom of choice but don’t make up scary bedtime stories.
You must understand there is a vast difference between ‘malnutrition’ and ‘under nourishment’. You can eat six times as much as your stomach can hold, and still be malnourished. Mal + Nourished = sick/unwell/inappropriate + fed. Obese people are, by definition, malnourished. Like the dude that tried to live off McDonalds?
As for “so-called organic”, you are letting your own preconceptions hang out. You are talking about the flashy, overpriced, hyped-up and contaminated schtuff on the supermarket shelf, Oz is talking about normal, non-corrupted food unpoisoned by all that stuff they put on your food to make it look cool.
But reminding you of all the Roundup in your breakfast is “…scary bedtime stories….” so I’ll let you go. Enjoy your vaccines.
P.S. “ending famine”? The poor are eating worse, while growing luxury crops for the better-off, while the rich throws away millions of tons of food every year, so it does not “negatively influence the market price”.
Go tell the people where the CIA arms ISIS about famine being eradicated, please, I dare you.
You’re not half as unpopular as me today. Didn’t know this site attracted so many chemistry-set farmers!
Bless your land, for it has found a loving caretaker, instead of a taskmaster. Few here seem to understand what I mean by that, I hope they get vaccinated soon.
Bluff from the ignorant.
I worked on a farm.
My relations still work farms.
None of them are what you claim and falsely portray. You certainly are not their superior in actions or knowledge.
Smart farmers seek advanced agriculture degrees because they plan to work their farms for decades and then pass on healthy thriving farms to their children.
Farmers do not waste money! Not even the huge agriculture corporations waste money!
Fertilizing hundreds of acres is not cheap!
The same goes for insecticides and herbicides!
Farmers do spray fields wantonly or profligately!
Back in the 1970s, the Federal government working through cooperative extension services promoted “organic farming”.
Their entire rationale was to allow niche farmers to raise the same crops that they can sell for more money than regular crops.
Improving food quality was not and never has been their rationale.
Unfortunately, as soon “organic” was entombed in laws and regulations, large commercial growers entered the markets and regularly force niche farmers into bankruptcy.
Those large agriculture growers have the funds to mount endless “organic” propaganda that seeks to prey upon weak minded believers in all things organic.
By the way. It is far easier to maintain and raise organic crops in a monoculture environment.
Farmers plowing their fields?
Before herbicides, the most effective method to eliminate weeds from a field was by deep tilling several times during winter.
USDA maintains a vast database of foods and their nutrient contents. While they may list a commercially named “organic” food just because it is a commercially named crop, not because there is any difference in food quality!
USDA does the same for Campbell soups and for the same reasons.
Well yes, but in nature, grasslands and forrests, it is not depleted, but over time, soil is built up. The CO2 is transferred from the air, to the bio mass, to the soil in the bio mass decay.
This step… “when plants die, they decay and their constituents become part of the soil” appears to have been poorly understood by said researchers.
No concept from this research was unknown to us at CSIRO in 1966 when we conducted multivariate trials of plant nutrition required during introduction of Townsville stylo legume for cattle grazing. It was an experiment on a national scale that was a large success and earned the boss, Les Eyde, a much-admired CSIRO medal.
There are, today, large schools of trendy intelligent but idiotic people who imagine that they have invented a new method named organic farming that will revolutionise the world. In truth what needs to revolutionised is their basic scientific education plus the concept of truth in attribution. Geoff S
How do plants deplete soil carbon? They take up water and minerals. I thought plant carbon in cell walls etc comes from CO2 in the air.
True. Most plants can be grown simply in water jars with minerals and reduced nitrogen added. The only carbon present in the water-fertilizer mix is inorganic carbon in the form of dissolved CO2 <–> H2CO3 (carbonic acid) + HCO3(+) (bicarbonate ion), and CO3(++) (carbonate ion) that helps maintain a slightly acidic environment the roots need for cation mineral release and transport across the cell wall and membrane.
oh like the hydro grown crops?
the ones with little taste smell or appeal
Hydro tomatoes from the Netherlands only with water and nothing else was a reason to name these tomatoes the 4. state of aggregation of water 😀
But hydroponic marijuana is pretty darn good. In fact, I’ve got some sitting around, if I could just remember where I put it….
The hydro crops I grow taste and smell great. And judging by the number of people that come by to sample these crops, I can assure you that they are quite appealing. Not only this but these crops are much preferred over any that are grown “organically”, whatever the hell that means.
Phosphoric acid is used to pH balance nutrient solution.
You are 100% correct. Even hydroponically with no soil, you add N, P, K, with traces of Mg, Ca, Fe, Cu, and a few other minerals – there is 0.0 organic C uptake by roots. Roots respirate CO2 and O2, and this is done in concert with mycelium respiration or with an air zone above the nutrient solution in hyroponics. Maybe if these people ever left their computer lab and ventured out into the field they would discover a thing or two. Real data is better than “synthesized” data, whodathunk!
Robert,
Just because you can grow plants hydroponically does not prove that plants grown in soil will not take advantage of juicy carbon compounds in that soil
The level of SOC in natural soil worldwide, left alone, stabilises out to a % or two by weight. There is a limiting mechanism to SOC and hungry planks are not excluded from that process.
Now we have these new age trendy organic farmers pushing for taxpayer funds to increase SOC because high SOC correlates with economic yield through better growth. The paradox is that you put money into gains in SOC so that plant yields can increase by taking more SOC out of the soils, along with everything else like P and K and trace element fertilisers. You create a cycle where you inject more of many nutrients for plants that grow bigger and are often harvested and taken elsewhere like to food markets and processing factories while back on the farm you continue to add fertilisers to replace it in the next crops.
Many of these added replacements eventually come from mines but these weird organic farmers hate mining but approve of imaginary unicorn poo to do without mining.
Note that I am generalising processes here. There are a few minor ways that can get around them sometimes, but that does not prove them wrong.
The overall outcome is that organic farming has no inherent advantages but has severe disadvantages over conventional, one being its concept capture by intelligent yet idiotic players who have no attributes to elevate them to the guru status they invent for
themselves while demanding other peoples’ money for their con jobs. Geoff S
Could you link to some of this organic carbon uptake by plants then? Organic carbon is used by the fungi and bacteria, the plants create the organic carbon via CO2.
It is obvious that these “researchers” have spent no time whatsoever learning abut soils, planting, and farming, both crops and trees. I’ll bet they are city born and bred, have had no AgEd classes at college level, and may have never taken a shovel and actually dug into the dirt at various and sundry locations to analyze soils.
I’m unfamiliar with the biochemistry of what a plant does with “absorbed SOC” from its root system. I certainly understand what it does with nutrients like reduced nitrogen, sulfur and phosphates, minerals (iron, magnesium, manganese), calcium, potassium, etc. But what does a plant do with SOC? What form is it in? Most SOC has come from dead plant debris that has been consumed by fungi and molds. And the roots store the plants energy as starches that can be metabolized.
I suupose what I envision is when the plants are taking up more mineral nutrients and nitrogen from the soil under elevated CO2, the soil bacterai and fungi are able to metabolize more of the SOC, releasing the nutrients and sending the SOC back into the air as CO2. That would be how SOC decreases, fungi metabolizing it to CO2.
Roots are one of a plants “sink” organs the photosynthesizing leaves assimilated carbon “source” can unload assimilates. If the leaves can’t shunt along their carbohydrate load then they have to store it on-site as starch & that bogs down a leaf’s operational efficiency.
This need for assimilated carbon “sinks” is why elevated CO2 usually results in more root mass (& thicker lower stem, another “sink”). Sink organs, like the roots, use a lot of i
those assimilates’ carbon for respiration & not only growth.
In flowering C3 plants at the vegetative to floral transition about 110 root proteins are up-regulated. At flowering roots put out more defensive enzymes into the soil; chitin-ases, glucsn-ases,& myrosin-ases. One (of 5 different) chitin-ases & beta 1-3 glucan-ase export increase peaks early & before/at flowering. The cited report’s variability between grasses & forests may, in part, be due to their respective time of flowering root-soil interaction.
Plants are making organic acids inside them & potassium (K) with carboxylic acids (ex: malate) get sent to roots. In the roots these acids are de-carboxylated; which releases K+ & also exports OH-. This is the root exudation activity that results in the influx of NO3- nitrogen; it’s an exchange made possible by carboxylic acid made from assimilates inside the plant & not carbon taken from the soil carbon pool.
Formation of roots certainly can use micro-nutrients; like iron, magnesium, zinc, boron, copper, molybdenum, & even cobalt. None-the-less it is the phyto-hormone auxin (“IAA”) that gets roots actually growing & the amino acid tryptophan in adequate supply promotes synthesis of more auxin. Plants make amino acids inside themselves (most after dark) & soil nitrogen is used.
Strigo-lactones are a phyto-hormone mostly made in roots that modulate auxin; thus one role is participating in root development. These are derived from carotenoids made inside the plant. Some strigo-lactones are exuded from the roots & induces fungal hyphal branching.
The symbiotic arbuscular mycorrhizal fungi hyphal branching includes mycelia that can extend into a root’s cortex. The ecto-mycorrhizal fungi mycelial sheath can cause plant root tips to split; that roots growth is impacted, but lateral root branching is then stimulated. Root associated fungi’s role in soil “organic” carbon accounting was probably overlooked by cited researchers; let alone parsing fungal differences between grasses & forests.
Am reposting this with a graph of root exudate levels with regards to various levels of CO2 in the air. Am pretty sure cited authors didn’t model for this data either.
Fungi and bacteria and worms and bugs and all those other miniature organisms are carbon based life. Soil health is largely a measure of the mass of such wee beasties growing in it. They do require minerals but most also require complex organic compounds which come mainly from decaying plants. Total soil carbon surely includes their masses.
I think you are right in your reasoning. And you point to a very important “partner” in this subject: microbial action. Microbial action is permanent at temperatures above freezing: if there is liquid water, microbes grow (metabolize and as a consequence grow), faster or more slowly, according to their species and the temperature. In their growth they produce (“excrete”, so to say) some organic substances which will attack chemically the mineral components of the soil, thus freeing them from their mineral crystal mesh “prisons” and putting them in the soil solution, from where the growing plants will absorb them. They need energy to grow and thus participate in this process. That energy comes from decaying (“eating”) the dead debris of the plants. Debris which, in turn, also have a lot of minerals that were used by the growing plant and immobilized in its hard tissues (leaf veins, stems, etc.); when the carbohydrate part of the plant debris is digested by the microbes, these entrapped minerals are also liberated into the soil solution and thus become available to be reused by the plants for their growth.
By the way, and before reading the original paper, I feel that maybe there is a lot of nonsensical reasoning about this matter. My antennae catch an indication of fowl play when differences are expressed as percent (absolute rate) instead of relative rates. It is easy for a grass to grow in weight 15 % in two or three days; now just think about 15 % more wheight in an apple tree during the same period. We must have this in mind when talking about “efficiency” or related indices.
In connection with that, the relation of the plant and its biomass production (from atmosphere CO2) and the soil organic carbon: a grass plant lives, produces roots, stems, leaves and seed, then dies and virtually all its biomass will go to the soil. One tree grows, accumulates a lot of the produced biomass in its permanent parts (the stems and branches, mainly), then its leaves will fall and that is the only carbon that will go to the soil: it is ridiculous to compare percentages or whatever between two such different life cycles.
From my experience in fruit production in a temperate climate (Portugal), soil organic matter can be increased with time, something that some years (two or three decades) ago would be considered impossible in any crop. Because, to maintain a relatively steady production of fruit orchards, the trees should be trained (by pruning) in a way that they maintain a constant size and shape during most of their lives. That means to cut most of the aerial growth formed in each year. All this wood is broken to chips and left in the orchard, along with the fallen leaves: in this way, the percent of soil organic matter can increase year after year (until a certain limit that depends on the soil type, tree density, kind of herbaceous plants used to cover the soil, etc.).
Now, think of a forest: trees grow and only dead leaves fall to the soil; then, some years later, you must thin the stands by cutting some trees, because the high density creates shadows, reduces photosynthesis and as a consequence reduce growth. But thinning means taking out timber, that is to say, the equivalent of all that woody matter that is cut every year and returned to the soil in orchards: timber goes away, does not incorporate carbon in the soil.
All these processes are very complex, cannot be grasped by a simple, shallow equation or statement. Is a very complex technical subject and there are many, many people around the world specialized in its details who contribute as professionals to the good (the best of their knowledge) management of orchards and forests. They are the real ecologists and environmentalists, and they are not criminals, as often the environment lobbies and NGOs seem to imply.
Trees and plants will just have to go
So they say – nowadays…
Replace them with artificial trees made of steel, silicon and lord only knows what else. Power them with windmills.
Downside, no bees, flowers, grubs, worms, birds but at least we can stop these bastardly trees participating in the great cycle of life.
In 1981, President Ronald Reagan said that trees produce more air pollution than automobiles.
Dense and extensive forested areas do produce alot of hydrocarbons, hence the Blue Ridge and Smokey Mountains.
And he was right
Plants are canceled.
And perhaps the ‘world leading scientists’ have also heard about how cycles of plant growth and shedding of dead material, followed by composting/breakdown of the dead organic material slowly but surely produces topsoil?
Have these nincompoops never asked themselves how topsoil of significant depth ever emerged, if plants actually growing made soil so infertile that they couldn’t grow no more?
Basic first classes in biology, not at university but in the first year of secondary school in the UK (i.e. at age 11) teach you that trees grow leaves in spring, photosynthesise and grow through spring, summer and early autumn, then the leaves and dead branches fall to the ground, whereby they are turned over 2-5 years (longer for bigger branches) into bioavailable nutrients.
I don’t know if these ‘world leaders’ have ever collected ‘leaf litter’ and put it into their compost piles – they may find that soil from a forest floor acts as a wonderful catalyst in the formation of superb compost.
Woods and forests in general build soil. Grass coverings protect soil that already exists, particularly in drier climates.
Amazingly, farmers used to leave some fields ‘fallow’ every few years to allow them to regenerate nutrients after growing crops for a few years. How on earth did those primitive idiots before the age of computer models know about all of this??
Sometimes, you have to accept that scientists wilfully write semi-moronic claptrap to ‘get published’ and to ‘be on message’ for the next grant proposal.
As a result, you shouldn’t read what they say and accept it literally. You should see them as like blokish cads who tell women that they love them when the truth is that they want to get into her knickers before humping and dumping her…..
I had a lengthy discussion/argument with a former colleague on this very topic. He claimed trees got all their mass by extracting material and water from the soil, I said most of the mass came from atmospheric CO2, water and some nutrients like Nitrogen in the soil. It is why Gromore is used as an artificial fertiliser. If it wasn’t that way there’d be a depletion of soil mass in forests of thousands of tonnes and grass wouldn’t grow over paths and rocks and peat in Scotland wouldn’t be 12ft deep
I learned about photosynthesis in my first year in Secondary School ca.1969. Why are so many otherwise educated, intelligent people ignorant of this?
And when the plants dies, guess what happens ! 🙂
The same thing as when a bear …. in the woods?
Nature. The original “recycler”!
So much has been forgotten since 1965. Back then it was well known that a planet’s so called greenhouse effect was related to atmospheric mass and thus independent of atmospheric composition though I never saw any description of the precise mechanism.
Unfortunately nobody ever retains old scientific texts so I haven’t been able to find any on the point.
The state of education over the past 50 years has declined enormously.
Not only in science but in everyday living Yesterday while at my part time retirement job of selling appliances, I took a call from a desperate man, his voice indicating he may have been in his thirties. He was desperate because his dishwasher was broken and it had been 3 days since he was able to wash dishes. I resisted the sarcasm of asking if he had a sink and sponge but instead just set him up for a service call.
(Your IP has a growing spam problem) SUNMOD
It is far from controversial that grasslands sequester far more carbon than forests. In colder climates grasses die back for winter, dropping their roots which are rich in carbon. They also do this when they are mown, cropped or grazed, because they are surplus to requirements. Trees do this once in their lifetime. Really old grasslands can have more than six metres of topsoil, whereas forests collect only inches. Every thing above the ground ends up, through rotting or fermentation ,back in the atmosphere, just like a cows’ fart.
Oh Dear, It’s called compost. The microbes, worms, fungi, beetles, etc – known collectively as decomposers, turn dead anything into recyclable nutrients. There is not a lot of nutrients in tropical soils because the nutrition is bound up in the biomass. This is offset by the rapid decomposition of dead vegetation so there is a constant equilibrium between life and death of plant material in healthy forests. This is why when tropical forests are cleared for crop growing or palm oil production the soil becomes infertile very quickly because the volume of decomposing material is less than the biomass produced and taken away, so the soil is quickly depleted.
Yes apparently there are people that don’t understand that soil depletion from agriculture is from the carrying away of the biomass produced by the crops. Commonsense should be added to the endangered species list.
If this isn’t a very elaborate April Fools paper then it’s a sad testament how out of touch with reality and basics the authors are.
The primary fail in this one, it is a Big Fail, is that CO2 is a fertiliser.
Sadly, despite my endless ravings, the misunderstanding is repeated, even round here, almost daily.
Wrong.
CO2 is a feed for plants. Like water is. Not fertilisers.
Got to learn to make the distinction
‘Fertilisers’ are things that are in short supply – the Liebig Limiters.
And that is where their experiments went wrong and gave crazy answers, each of the 108 experiments had a different combination/mix of Liebig Limiters
Any one or more of the 52 chemical elements that me, you, plants, critters, bugs, bacteria. viruses & fungi require in various, usually very small, amounts.
To sort this thing out and to prevent this Entire Planet Earth becoming a twin of Planet Mars, some considerable number of people have got to get their heads around that.
The mistake has been made plenty times before – classically when some tribe/civilisation has had a ‘Warm Period’ and then promptly vanished.
In every case, the Warm Period was caused by the disappearance of the Soil Organic Material via ’tillage’
Not that that caused the ‘warm’
No, not the CO2 that was released.
It was the subsequent disappearance of all the water that that stuff retained in the soil.
Everywhere you look in this Big Old World, water cools.
Water (vapour) is not a Green House Gas that causes heating of the Earth surface.
viz: The dirt and the water.
Earth Surface is that stuff touching the soles of your feet and squeezes between your toes.
Earth Surface is NOT where thermometers are usually placed, not even at just 5 feet above.
Increased energy and or temperature there is useless to Life on Earth
Yes it makes things comfortable for us, but let’s try a bit of humility shall we?
OK. Water absorbs ‘heat’ energy/radiation, emanating from the surface, in the atmosphere.
But, once that energy is in the atmosphere, it is spent and useless.
It is the stuff going out the tail-pipe of your car and it matters not one jot that its trip to Alpha Centauri and beyond was delayed by a few microseconds.
That energy can not return into the land or the ocean. Entropy says ‘no’
Heat energy in the atmosphere is on a one way trip to perfect complete oblivion.
Crazy innit.
But like El Nino, supposedly a ‘warming event’ in that the temperature goes up, Nino is actually dumping energy into the atmosphere and thus outer space.
El Nino is a Cooling Event – so is atmospheric warming.
Back to Warm periods – and the ends of the civilations that created them.
They were all fairly minor and ‘local’ events.
OK theose involved had a bit of a rough time but, in the Grand Scheme of Things, it didn’t matter.
Plenty other tribes were ‘up and coming’ Humans would, did, survive.
But this time, there is effectively only One Tribe
I suppose helicopter (blows kisses to NASA) pilots might find something to do on Mars, the whole rest of us, maybe not so.
Great reminder of back-to-basics.
This has to be the dumbest thing I’ve ever read. Mars still has all of its minerals. They routinely get redistributed in planet-wide dust storms. Nobody ever tilled Mars. Mars lost its water because it has no magnetic field to stop the energetic solar wind (mostly Hydrogen and Helium) from crashing into atmospheric vapor and imparting enough kinetic energy to knock the water vapor out of the planet’s gravitational grasp. The Earth’s magnetic field, along with stronger gravity than Mars, is what prevents Earth’s water from escaping to space.
Water vapor is a greenhouse gas, the most powerful one. It works by re-radiating a portion of the infra-red radiation that would have escaped from the surface directly to space back to the surface. By colliding with other air constituents it also heats the atmosphere. It doesn’t matter that it does this fast, it changes the radiation balance.
Water both heats and cools. It cools by absorbing heat from the environment when it evaporates but it releases all that absorbed heat when it condenses (as in rains). That’s one reason why a rainy night is warmer than a clear night.
You’re giving people like me who are skeptical of the climate crisis scam for solid, well thought out, physically-based reasons a bad name by claiming to be a skeptic for your crazy reasons. Give it up.
I synthesize data all the time. Its the very best data because I don’t have to waste all that time observing and making silly notes. The computers don’t care what they’re fed, trust me on that one.
Oh my … I’ve heard that before. I think it came from the IPCC.
I’m correct 100% of the time using synthesized data so it proves that real data needs thrown out – climastrologists.
If plants remove carbon from the soil, how do peat bogs develop?
Cultivating soil aerates it and the carbon/organic matter content can be reduced.
An example on the peat soils in the fens where Holme Fen had iron posts driven into the clay layer under the peat. They now show the peat soil has oxidised and shrunk by 4 metres since 1848.
I’m glad that cr of WUWT encouraged this post. It was more confirmation of the appalling state of “Science” in the 2020s.
Be gentle with the guest? I say give him a regular slot!
I was going to recommend that the impoverishment of the soil be rectified with planet saving eco friendly organic fertilisers.
Then I wondered how we would produce blood, fish and bonemeal fertiliser if we couldn’t kill and process animals and fish as we all went vegan.
Then I thought of suggesting we manufacture growmore fertiliser to solve the problem of not killing animals and fish to eat. (Metaphysics always confused me in my philosophy classes).
Then I came up with the answer…..cover the planet in green toilets…_
I am somewhat disappointed at the quality of this article. One aspect not mentioned above is that plants not only transport photoassimilates to the roots for energy and building new roots, quite a bit of these photoassimilates are excudated into the soil. Several of these exudates are acids that are used to improve phosphate dissolution from the soil particles such that they can be taken up by the roots. Also, some of the photoassimilates are specifically transported to the roots for supporting the microbiome as many fungi-like entities can help support the plant to take up nutrients (think a.o. of nodules for N2 fixing). From this perspective an increase in SOC is expected when the shoot performs better. However, loss of nutrients or change of availability thereof (not identical) may counter this effect. Increase of root growth can happen, but need not happen if transpiration goes down so water loss form the soil is reduced. Reduced soil water uptake can affect the O2 profile in the soil as water uptakee creates a very slight air under pressure that sucks air into the soil. All these factors contribute to the development of the microbiome and in howfar carbon is indeed fixed in the soil. Here, intuition is not the best guide as there are way more factors, over conflicting ones, that play a role. Due to the complicated nature of this subject I prefer to stick to observing root growth using MRI and root water uptake using my own technology. This is already more than complicated enough.
Your critisism on the scientific content of the article (apart from the possible political issues) as if this issue can be understood by some base knowledge is not justified. This is similar to using overly simplistic models for climate predictions, it can easily lead to the wrong conclusions, whichever they may be.
Roots respond to osmotic pressure. For example: in hydroponic substrate they develop relatively more thick/fleshy, while in soil/solid substrate they develop relatively thinner with root hairs growing behind the tips.
Events like inundation of roots (soluble O2 in root zone affected) provoke ethylene phyto-hormone levels to rise. This in turn results in modulation of auxin phyto-hormone localization in roots.
Ethylene & auxin tussle during lateral root formation. High ethylene reduces lateral root elongation; decreased ethylene removes the inhibition on lateral roots’ growth. The dynamic is how high ethylene up-regulates the enzyme (tryptophan amino-transfer-ase) that boosts levels of auxin in the root stem cell (meri-stem) niche. Which creates the downstream condition of auxin accumulating in the meri-stem (& not being busy).
Elevated root ethylene has greater effect on lateral root formation than does in regards to inhibiting primary root length. Ethylene & auxin function in respect to one another in different dynamics depending on whether their context is elongation of roots or formation of root hairs.
Brassino-steroid phyto-hormone contributes a boost to root growth because it serves as a rate limiter of auxin transcriptional response. Plus brassino-steroids configure cell actin in a way that orientates auxin shuttlers (“PIN”) in a polar manner; that establishes a local auxin gradient that works out as auxin responses.
Rhizobium root nodulation involves what is called their “NOD factor” secretion. NOD stimulates auxin synthesis in the roots in a way that increases cell division in the root cortex. The actual nodulation is a result of organo-genesis started by a synergy of auxin & cytokinin (another phyto-hormone). [Incidentally in roots, ethylene levels also impact cytokinin’s activity; be it in a meri-stem zone, elongation-differentiation zone & transition zone. However ethylene is not a factor in regards to the amount of cytokinin accumulating in a root meri-stem.]
In earlier comment I mentioned strigo-lactone phyto-hormone. Sorry, no time now to expand on that.
After the continental glaciers retreated from North America- most soils had little or no carbon. After some centuries after the forests reclaimed the land- the soils had carbon. Plants add carbon to the soil- and do not deplete it.
And I was taught about plant succession in grade school and how topsoil was formed. I grew up in a State that was mostly covered by ice in the last glaciation and scraped clean by those glaciers.
Woodlands: Grasses ==> Shrubs, Scrub ==> Big Trees (plenty of near surface water available to roots) ==> Thinner layer of topsoil
Prairies: Grasses ==> Shrubs & Trees, mostly along streams ==> Very deep layer of topsoil
Yeah, pretty simplistic, but “even a 4th grade kid” got taught the broad basics in the ’60s. The farm kids learned even more in 4-H and Ag School.
Oh Joy, someone has discovered the Carbon Cycle. We are all saved!
Mom could have told these researchers a thing or two. She was the daughter of a Texas sharecropper and plowed behind a mule.
We had a very large food garden. The property was bordered by Sugar Maples (source of income from the sap).
Every Fall, I had to rake and gather all of the leaves from the Maples, spread them on the garden, and then burn the leaves.
It seems she knew a bit of something about replenishing the soil due to the food plants taking nutrients out and depleting the soil.
.
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Henry Gillard was right to poke fun at this research and their
conclusionspuzzlement. The only credit the researchers might take is for (possibly) quantifying soil carbon uptake and depletion a little more accurately than was (maybe) previously known.Seriously:
Was anyone else struck by the similarity of the pattern? Aka: The Earth’s temperature …“has been observed to increase, remain unchanged or or even decline”. (hello)
Unseriously:
From: Alinsky’s Rules for Scientific Radicals: “While cyclical processes seem impervious to agenda driven science, the reality is that they offer rich pickings when broken down into components. And once standing on their own, the components are easily amenable to the standard treatment: Identify it, Isolate it, Demonize it. “
Without getting into the weeds, what this paper seems to allude to is that in order to get back to the “ideal soil steady state” (Martian or Lunar presumably) the preferred terraform is the anoxic peatland.
If any of my graduate students had come to me with this problem, and wanted to elucidate the mechanism, I would have directed them to spend the next four years of their lives managing and optimizing my household compost bin.
(facepalm)
Not sure why the author thinks the article makes a case for the stopping of tree planting. If trees have no net effect on ground co2 and they love the extra co2 in the air, then since co2 levels are going to continue to increase regardless, then any trees planted now will experience increased growth rates year after year, enhancing the effectiveness. Probably choosing deciduous trees instead of evergreen would make sense.
From the abstract quoted in the above article:
“Here we synthesized data from 108 eCO2 experiments and found . . .”
Synthesized data . . . WTF? I stopped reading right then and there.
Trees have their own intrinsic value so i will continue planting them regardless of their effect on soil co2.
I will write to Stanford instead.
But there is a long list of letters to write.
I think i need a form letter.
Insert name of school, researchers and crap paper title, click send.
A fillable PDF will work
All wrong. Trees and other plants add carbon; they don’t remove it. Indeed, every single atom of carbon found in soil was once atmospheric CO2. Photosynthesis takes the carbon from the air and puts it in the soil.
Tree roots break rocks. Roots acids dissolve granite, basalt, and limestone. Tree roots have been observed penetrating cave ceilings hundreds of feet below the surface. Trees make soil from fresh lava flows. All the carbon comes from the air. Roots are the source of soil organic carbon. The more they grow, the more there is.
Soil carbon can be removed by erosion or fire — at the surface. Otherwise it doesn’t go anywhere. Under some conditions after millions of years soil carbon turns into oil or coal. Then it can be removed by mining. But plants do not remove carbon; they put it there.
Dumb dumb dumb. Everybody grab your craniums and try to think for a change. C’mon now. You can do it.
Nope. As CO2 increases, plants share more resources, particularly water with soil and symbionts.
If anything, I’m far more scared we’ll come up with economic CCS than I am of global warming.
https://twitter.com/aaronshem/status/1126891482105954304
It’s not surprising that increasing the concentration of CO2 in the air would not deplete the soil organic carbon in forests, particularly temperate forests. Even if some soil organic carbon was absorbed into trees during the growing season, the leaves dropped to the forest floor in autumn would decompose over the following year, returning organic carbon to the soil.
This would be less evident in grassland, since grass becomes dormant in winter but not all of it becomes detached from the roots and decomposes.
As for farmland, farmers would probably welcome higher crop yields due to higher CO2 concentrations in the air. But farmers have been fertilizing their crops for centuries, using whatever they had available, including dead leaves from previous years’ crops, or manure from livestock, which recycle organic carbon to the soil.
So what’s the problem?
So I have a veggie patch and go through a 2 year cycle of making soil by composting old vegatable matter. It makes new highly fertile earth. These clowns don’t seem to realise that plants enrich their own environment – and have done so for around 300 million years. If you grow cash crops or over farm that is a different matter, but nature does a pretty good job.
Being just about to dig up and raise the bricks around my perennial beds, I am very aware of the fact that grass makes noticiable amounts of soil over a 6-7 year period. The lawn side is more than 2inches above their level. Maybe they sank a bit, but for the first 3 years they were a good mowing strip.
Well I guess that puts the end to biofuels.
For most of the Phanerozoic (last half billion years with multicellular life) CO2 has been at more than 1000 ppm.
What “toll” did that take on the soil?
Yet another alarmist paper that fails the test of even one of its authors having an IQ higher than their shoe 👟 size.
It’s a mistake to consider “forest” as a single category. Tropical rain forest is completely different in its carbon cycling to temperate forest. Tropical rain forest keeps nearly all its carbon in rapidly cycling life forms – trees, plants, animals, fungi. The soil is very poor. That’s why if you cut them down you’re left with a desert. Temperate forest on the other hand has much more rich humic soil.
This study makes another mistake of treating carbon like a zero sum game. Where increasing CO2 enriches plant growth, it will attract more life of every kind – birds, other animals, insects, fungi etc. These will end up becoming soil carbon.
In simple terms, experiments where alleged researchers grew plants under elevated CO₂ levels.
That is, they grew plants in small containers under circumstances where they could control the atmosphere.
In their alleged collection of eCO₂ experiments, they grew plants in soils;
Yet, even after their digesting information from 108 eCO₂ experiments, these alleged researchers somehow sum everything into a CO₂ cause and detrimental effect?
Back in 1952, researchers investigating elevated CO₂ growth effects and detriments recognized that plants outgrowing their environment was mostly due to constrained environments, not elevated CO₂ levels.
Below is a report on some early work that shows how much stuff is taken out of the soil by growing plants (next to nothing).
The author is Gunther Wacherhauser a little-known patent attorney and amateur scientist
http://www.the-rathouse.com/2011/Wachterauser-Use-of-Popper.html
The year 1644 marks the death of a great scientist, the Belgian physician Jan Baptist van Helmont. He had spent his life and fortune on scientific research. Yet during his lifetime he published nearly nothing for fear of the Inquisition. In his last will he asked his son to publish his results in the form of a book: Ortics medicinae.
“I took an earthenware pot, placed in it 200 pounds of earth dried in an oven, soaked this with water, and planted in it a willow shoot weighing 5 pounds. After five years had passed, the tree grown therefrom weighed 169 pounds and about 3 ounces. But the earthenware pot was constantly wet only with rain … water. … Finally, I again dried the earth of the pot, and it was found to be the same 200 pounds minus about 2 ounces. Therefore, 164 pounds of wood, bark, and root had arisen from the water alone.”
Now, what is the philosophical methodology. behind this experiment? Unfortunately, the record is silent on this point. So it would seem to be legitimate to look at this report through the spectacles of our current philosophy of science; in fact alternatively through inductivism and through Popperian deductivism. We may hope for a double benefit: (1) a clear understanding of the historical report; and. (2) a clue as to which of the two mutually, exclusive philosophies is right and which is wrong.
From the platform of our current state of knowledge it will strike the inductivist as most important that van Helmont’s conclusion is wrong. This must mean to him that van Helmont did not apply the proper inductive method of science. He reports only one single experiment. There are no repetitions. He did not repeat the test with 500 willow trees, or with different kinds of trees, or with different kinds of soils. One single experiment was enough for him. This makes no sense to the inductivist. And so the inductivist must come to view van Helmont as one of those queer, irrational, prescientific characters, amusing but irrelevant.
Now let us apply the Popperian view of science. Van Helmont was operating within a rich context of Renaissance knowledge. It was widely accepted that matter does not spring from nothing, nor disappear into nothing. And it was an equally widely held theory that the substance of growing plants comes from soil. The first theory was to van Helmont what Popper calls unproblematic background knowledge. The second theory was to him problematic and in need of testing. From both theories jointly he deduced a testable consequence. The weight gain of a growing willow tree must be equal to the weight loss of the soil in which it is rooted.
He carried out an ingenious experiment, bringing the soil before and after the growth period to the same reference state by drying. The result did not come out as predicted. 164 pounds of added tree .weight compared to only 2 ounces of loss of soil weight, a small amount well within the experimental error. In the face of such a glaring result, van Helmont rightly decided that repeating such an experiment would be a waste of time and money. And so he decided to consider the soil theory falsified.
Van Helmont operated with a limited set of two possible material, elements: earth and water. Having eliminated earth, the only remaining possibility was water. His result then was to him proof by elimination. This makes it understandable why he ends his report with a definitive conclusion: ‘Therefore, 164 pounds of wood, bark and root had arisen from water alone.’
Today we hold that this is wrong. One of the important nutrients of plants is carbon dioxide, a gas. Gases, however, were to van Helmont non-material spiritual entities. Therefore, by his own prejudice, he was prevented from including gases in his set of possibilities. It is ironic that it is van Helmont, who discovered that there are gases other than air, who coined the name ‘gas’, and who even discovered carbon dioxide.
Plants extract little to no C from soil – that should be fixed, see “photosynthesis”. Anyway, net gain in SOC in grasslands is not surprising except that it was impressively high, nor is the forested result claimed. Increased growth will indeed increase nutrient extraction from soil, which is returned if the biomass isn’t harvested and removed. Atmospheric CO2 fertilization isn’t “hard on the soil”, which is a silly phrase anyway.
In Riverhead Forest, Auckland, New Zealand, NZ Forest Research Institute (now called Scion) established what was colloquially known as the “Museum Trials” on land just cleared of the original native forest. The soils are consolidated clay, somewhat compacted by the logging, very low in P, and quite acidic, as natural soils in NZ tend to be. Planted in Pinus radiata in, if I recall the details, 1926. In a fully replicated trial, a single dose of Superphosphate (P and S), of (I think) 25 kg/ha was applied once only to the treatment plots.
The response of the trees was astonishing. Final volume of wood, after about 50years, was many multiples of the control plots.
What was really interesting, was that organic carbon in the soil was much higher, soil porosity greater (better draining – the soils are naturally imperfectly drained to waterlogged much of the year), cation exchange much improved. The soil A horizon much deeper. By all measures, the soil was much improved over the control plots. The P levels, had declined very little since that original application.
Following logging, the plots were re-established, with no further treatments. As of my last involvement, 20 years ago, the trees in the treatment plots were still outperforming the control plots by a considerable margin.
The compelling conclusion is that trees, and forests, are very effective at recycling elemental nutrients, where those nutrients are a limiting factor.
Not my field, but New Zealand being the pastoral farming mecca that it is, my understanding is that properly managed pasture is even better at buiding up Carbon in the soil, from articles I have read over the years