It is intriguing how the world fundamentally works, with its cycles, driven mainly by solar energy. Which can be traced back mainly to the yields of land, as I found out earlier. [1,2] (Land that has virtually disappeared from economic theory as a production factor).
But yields from land is not endless either. How does that work, I wondered. Take potatoes, for example, something that I recently studied in the ‘Enriching Agriculture’ project (the EROI calculations and such, more later). Potatoes being also our basic diet, not by coincidence the subject of a famous painting: the potato eaters, by van Gogh.
For example, put one potato in the soil, and get roughly 5 in return. Then you put four away, put 1 in the ground again and get again 5 in return. So that is how it increases every year by an equal amount. But that also means that you extract nutrients. Which are replenished through wind and rain, but not at the same rate. Basically you have to eat and defecate those 4 potatoes, and spread them out over that land again, otherwise at some point in time it will not work anymore … As is beautifully recorded in the book ‘ Farmers of Forty Centuries ‘ 
What you, as an human being, actually extract definitively is mainly the energy content, the solar energy converted and stored via that land in the for of potatoes. The rest of the ingredients, all from inside the earth, is only intermediate stored for a short or longer period of time, and is thus released again, via also faeces , and definitely at the end of life. That is the basis, the cycle that must be sustainably maintained.
A tree is essentially nothing else. Its is just another organism, albeit that this process is integrated and “automated”, so that a tree does not have to be mobile, like the human organism, that has to go out to “collect’ find its food, the Hunter-gatherer behavior.
The tree therefore also lives from that extraterrestrial energy flow, and the minerals and nutrients go through the same cycles. Extracting trees from that forest, and storing the wood in buildings, for example, is therefore just as much removing all kinds of substances from those cycles, like humans do, which might induce one-way traffic. If that exchange works in a balanced way, a certain delay in those cycles is not an issue. However, over the past thousands of years, trees have been excessively withdrawn from the stock. As a result of which the balance is disrupted. One organism, trees, has come at the expense of another, mankind.
And even that was not enough for the human organism, which started using “fossil” trees and other organisms (peat, lignite, oil gas, coal), disrupting another cycle, that of CO2. Which had just reached an equilibrium in which that human organism could thrive, but unfortunately, the same organism that thrived by that balance disrupted the balance, destroying its own environment.
Everything can only “be”, be itself, but not extract anything permanently, that is, surrounding itself with permanently extracted fixed amounts nutrients or molecules. Then the cycles no longer work, they run short of ‘fuel’ . In that case , another species or a whole ecosystem degrades. By definition. It is therefore important not to use, to abstract , more than the system can temporarily miss without the resource systems itself collapsing. At least, if one as a species wants to survive. Otherwise, that species dies out and becomes part of the constant process of evolving species.
So you could abstract and store something to a certain level, a level that system can still handle, but where is that optimum? Which applies to all raw materials in whatever form. Also for so-called ‘renewable‘ raw materials, if they do not renew like previously, they also become what we call ‘non-renewable’ raw materials: if you only extract from the soil, it depletes and even the regrowables don’t regrow anymore. That is what is currently happening with our land and soil , its exhausted.
In fact it is the constant factor: one person’s death is the other’s bread… something can only grow if something dies elsewhere… Then there is balance. This is also applicable for living species : they come and go and the nutrients become available for the other.
‘Progress’ then lies in what is constantly (re) growing, perhaps as a smarter variant … Which implies that for humans there are only two routes: or we are doomed to die out as a race, for the benefit of something that is ‘smarter’ (or better adapted ), or we ourselves should become smarter … or adapted , I how we deal with the limited amount of resources.
Which in fact is a wrong question, the crux of course lies in how to define ‘progress’ . In fact, progress is ‘change’, a concept like ‘smarter’ is unknown to nature. Physically speaking, you could define progress as the concentration of raw materials, the decrease in entropy. We live in the only place in our solar system where this actually can happen, and happens, the rest of the universe is on its way to chaos. That’s the real evolution of the universe. Here on earth, however, it is a kind of counter-evolution, against the current, thanks to an ideal position in that solar system and the constant supply of energy.
But that is precisely what the human species does not practice, it de-concentrates stocks, that then disappear, diluted into the background. Of which the ‘regrowables’ resources, biomass, have a self-healing capacity, without human intervention, But we also de-concentrate the substances that do not renew themselves (within relevant time scales). Only at the expense of enormous energy efforts can these be concentrated again, efforts that are beyond the capacity of that species itself.
Re-concentration of substances, reducing entropy, is therefore mainly manifest in biomass. And with that, the human organism is essentially convicted to life from and with biomass organisms, in balance with the nutrient cycle. At least, if he will become ‘smarter’ in time to restore the balance, or in other words : becomes ‘entropically aware’, and the system has by then not changed in such a way that other more adapted species have take over , and is doomed to disappear as a species himself.
Biomass, substances that re-concentrate again without the help of humans, organize themselves in plants and organisms. On timescales that specifically make that life possible. As a result of which the human species can withdraw part of that stock temporarily, to exist as a species. And if he is “smart”, he knows how to keep the balance.
In fact, everything revolves around land *, with soil and everything below the land, and air and everything that is above the land. Since its not only the life below that determines the quality of the land, its also whats above: the air contains nutrients, pollen , water, oxygen, and a lot of insects that contribute to land production. Not to mention solar energy, as the most important component of the entire system. Without solar energy nothing works anyway.
“Above and below land” are two mirror images that come together on land. I may be a ‘soil ambassador’, but that should be read as a : ‘land ambassador’ … 
And there are quite a few current “land needs”, such as:
– trees, to capture CO2
– to produce biobased raw materials
– to capture renewable energy
– to re-wild land
– as water storage
– for housing above sea level
– for food in closed cycles
Not to mention land in its role to limit environmental problems, for example nitrogen, concentration over time per land surface, and not the least to grow trees, that in this case seem even more important as so far assumed, via trees CO2 is fixed not only in the tree itself but also in soils in large amounts, driven by the hydrological cycle, as Walter Jehne points out. 
Land plays a central and crucial role in a balanced system. Reason enough I would say to control land and land use by ourselves … After all, on land we have to survive, in a world where countries are increasingly dependent on themselves (there is no free other land to occupy, cultivate or develop or colonize), and it cannot be that the use and depletion of that land is determined by all kinds of subjective and partial interests, by private needs and economic lobby groups, thus exhausting the potential of its inhabitants. It must be secured for us and our future, to meet our basic needs. 
It is also not at all about ‘special interest groups’, even if they are local: the importance of the land itself, the soil and the air above it must be central, and what it can deliver on a sustainable basis in terms of basic needs 
And that will become increasingly important because in more and more countries “take back control” will be a leading theme. Just look at the US, China, and Europe, which is increasingly forced to take responsibility for itself. This will increasingly play a role at country level, look at Hungary, Poland, United Kingdom, etc.
What must be done is that all land comes under the supervision of the government (read: society), and that property is seen as leasehold. And leasehold is only granted if the land itself benefits, if its not exhausted or over-exploited, or abstracted from free availability. And then you can define soil types for different uses.
We need a ‘party for the land, a party for the soil. Not a ‘party of money’, or a ‘party of the peasants’, or a ‘party of liberty’, or of ‘labor’, not a left or right party, not even a party of the animals, but a party of real capital: the land with everything what is below and above. Keeps animals, plants, people, but especially air and soil in balance, so that everything in between can flourish, and not only humans, but asa whole for humans to flourish for the length of days, years, decades, centuries.
The land determines the potential of what is sustainable and what is not. It is the most important link between heaven and earth, between solar radiation and growth. The only growth that really matters, the rest is eating into stocks and potential.
* land can also be seen as land that is under water, that happens to have condensed water above it instead of evaporated water. Call it water land and air land. For which exactly the same applies. Only, we once crawled out of it and, in a sustainable balance, have only limited access to it.
 biomass growth is our reference: http://www.ronaldrovers.com/biomass-growth-is-our-reference-back-to-the-forests/
 living from 2 ha. : http://www.ronaldrovers.com/living-from-2-hectares-and-not-even-that/
 interview als bodem ambassadeur: https://bewustbodemgebruik.nl/actueel/aardse-held-ronald-rovers/ (Dutch)
 Monbiot on commons, Schumacher lecture, minute 2-46 https://www.youtube.com/watch?v=63WSvrquIPU&feature=emb_logo
 ’terragenda’ manifest ( Dutch) https://bewustbodemgebruik.nl/wij_doen/terr-agenda/