Would a world with exclusively human-edible plants despoil the soil? Or is it possible to have an hypothetical world where there is no grass but potatoes and tomatoes, and no pines or oaks but only apricots and apple trees?


I remember I had been told that the list of plants usually related to human consumption, I am not saying "potentially edible" but "commonly found in whatever supermarket", like apples or onions, are a too-short list which would despoil the soil if an extensive cultivation of said plants were not to be backed up by the chemical cycles engendered by other and different forms of vegetal life which are not directly linked to human consumption.

I have not an exceedingly firm idea of what I am trying to accomplish, I just need a world where you need not to farm because literally every tree you see bears edible fruits and literally everything which springs from the ground is edible in the same degree of tomatoes, onions and potatoes.

My basic idea is a small degree of human intervention akin to seeding a world recovering from massive volcanic winter, where there is nothing left of the previous world (trees, animals, buildings) but the soil is obscenely fertile, so humans can decide what to plant but all that is not selected by humans won't grow spontaneously anymore for it was zeroed by lava and cold.

I want to know if such a world is feasible or if after a while having a limited set of plants will run out some particular nutrients making this whole ecosystem to crumble upon itself, something which was avoided on actual Earth by having literally hundreds (if not thousands) of different species for each square mile of wild nature which allowed an ecosystem like natural forests, which is richer than cultivated lands, where constant fertilization is needed to prevent the soil from being despoiled by cyclical cultivation of the same limited set of plants.

I would like to know if it feasible a world where an ecosystem like USA forests (so as rich and green and free from the necessity of human artificial fertilization) could grow up and thrive if composed exclusively by species which are commonly found in a store instead that of hundreds of different species (of which humans eat only a 5%).


I do not think I can say it better than this. In that case I give up and will leave it unanswered or rather delete it. This is the last attempt. I need a world where somebody lost in a wood or kicked out by home could live its whole life by just picking fruits from trees or rooting out onions thanks to the fact that in this world every single tree in a forest bears fruits and every single thing you see in the ground is a onion or a carrot or a pumpkin and so on. Is it feasible or such a limited amount of species would run out of nutrients and despoil the ground?

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    $\begingroup$ Both pine seeds and oak acorns are edible, for the record. And, also for the record, wheat, maize, barley, oats, rye, and rice are grasses. In a world without grasses we would have trouble feeding eight billion people. $\endgroup$
    – AlexP
    Commented Jan 2 at 23:35
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    $\begingroup$ Please clarify if you are asking if humanity could engineer a world with nothing but edible-by-humans plants or if the world evolved to such a state? Further, please note that we have only one data point to work with: Earth. So it's unlikely anyone could rationalize with science an evolved ecosystem that's entirely edible by humans. But I can plant a garden and fruit trees and neither depend on anything but the garden and fruit trees. So I expect we can engineer it. Nevertheless, it's up to you which one to ask for. $\endgroup$
    – JBH
    Commented Jan 2 at 23:57
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    $\begingroup$ One more thing: you mention potatoes and tomatoes. That's a curious choice as the stems of the plants are poisonous, but the fruit of the plants is edible. Where are you drawing the line? Is a plant considered "edible by humans" if any part of it can be ingested regardless its nutritional value? (By that definition almost every plant on Earth is edible.) $\endgroup$
    – JBH
    Commented Jan 3 at 0:00
  • $\begingroup$ Pine leaves are edible. You might consider rewording this to "A World With no Plants Highly Toxic and Utterly Indigestible to Humans" $\endgroup$
    – elemtilas
    Commented Jan 3 at 4:18
  • $\begingroup$ Are you asking if cultivating nothing but plants that (whose parts) humans use for food is sustainable, ie. can it be done as long as it is needed? $\endgroup$ Commented Jan 3 at 5:00


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