Among other things humans are fertiliser. Orcs are capturing humans as slave labor and fertiliser. What do human bodies produce/store that plants need to grow?

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    $\begingroup$ Homo sapiens, "wise man"; note the s at the end. Tthe plural would be homines sapientes. $\endgroup$
    – AlexP
    Commented Aug 24, 2017 at 22:12
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    $\begingroup$ You already stated why human is needed by dragons and orcs. What's the problem? $\endgroup$
    – Vylix
    Commented Aug 24, 2017 at 22:29
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    $\begingroup$ Confused why all three aren't using human slaves. Even if you're going to consume them in one way or another, might as well get some useful work first. On another note, what does Ubisoft have to do with this? $\endgroup$ Commented Aug 24, 2017 at 22:51
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    $\begingroup$ What kind of diamond is made out of steel? What I do not get is why only the Elves can use humans as batteries? Why does every species need a different use for humans? The food part, well, maybe if it's the only thing dragons eat, but that's a much weak motivation. Maybe the problem is that your question isn't clear enough - there isn't even a single ? in there. Do you want to know what Orcs fight about? Do you want to know if fertilizer is a viable reason for war? Do you want to know how one fights a war over food? I can only guess what your question is tbo. $\endgroup$
    – Raditz_35
    Commented Aug 25, 2017 at 4:30
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    $\begingroup$ Welcome to WorldBuilding WorldWeaver! Please note that this is not a discussion forum where we discuss why your characters would do something. And the way you formulated your post I thought you wanted to know only about the Orcs because that's where you state that you need help, until the second to last paragraph. Please focus on one question per post. For example "How effective would humans be as a fertilizer for crops?" would be a perfectly fine (somewhat gruesome) question. You can always wait a bit and ask another question in this universe later. See tour and help center for more info $\endgroup$
    – Secespitus
    Commented Aug 25, 2017 at 7:14

2 Answers 2


Nitrogen, Potassium, Phosphorus, Calcium, Magnesium, and Sulfur

Common fertilizers have these elements. Plants even become predators to get these valuable resources! Decomposed animals tend to give up these nutrients to plants.

We humans need these elements. Bones, neurons, muscles, and animal bodies in general need these things for structural and functional purposes. These animal bodies need to decompose in order to make these nutrients available for plants.


Plants also need carbon dioxide. No carbon dioxide, no breathing for plants. You and I (and other animals) give up carbon dioxide when we breathe. More than 95% of carbon found in plants comes from the atmosphere. As a side note: cremated bodies buried under trees don't become part of the tree. The tree isn't interest in the carbon its roots find and the cremation process burns off most other compounds. If you want to help a plant grow, just keep breathing.

  • $\begingroup$ Thanks you two you've bumped my afternoon from normal to good. :) $\endgroup$ Commented Sep 1, 2017 at 17:14
  • $\begingroup$ "This is why people generally compost in one spot instead of all over: the decomposers don't have to bother finding bodies." Alas, no. You use a single compost pile to get higher composting temperatures, which produces faster compost times and kills harmful bacteria and other pests. $\endgroup$ Commented Jan 30, 2019 at 16:49
  • $\begingroup$ @WhatRoughBeast Duly noted $\endgroup$
    – PipperChip
    Commented Jan 31, 2019 at 15:57
  • $\begingroup$ @WhatRoughBeast: And also because it keeps your garden neater. If I don't rake up leaves &c from my flower beds, the smaller spring-flowering bulbs would scarcely make it through the layer of dead stuff. $\endgroup$
    – jamesqf
    Commented Jan 31, 2019 at 19:41

The only advantage humans have over other animals is intelligence and adaptability. That is why humans were used as slaves throughout history. Animals are notoriously inflexible and untrainable except for routine proscribed tasks. Humans have the ability to adapt their performance to very diverse scenarios. This is also why robots have not yet taken over all manufacturing tasks of human labor.

Otherwise, humans would be particularly useless to Orcs. Other animals would be much more useful, less troublesome, easier to manage, having a shorter and more prolific reproductive life cycle, and being lower on the food chain, more economical to raise. We also have very little nutritional or food value, with respect to other animal food choices. That was our main evolutionary advantage - we just weren't appetizing to other predators, so they left us alone. Too skinny, not enough meat to bother with.

Really, if it is all about just fertilizer and energy sources, humans are a very poor choice for domestication. Like farmers clear fields of weeds to increase production, humans would be among the first species Orcs would want to totally eliminate and not keep around. Sort of like what the white man has done to indigenous peoples.

It is only because humans are basically narcissists that we THINK we could, or should, be useful to Orcs, and that we THINK there should be a good reason for them to keep us around.

  • $\begingroup$ The question is "What do human bodies produce/store that plants need to grow?" Your answer seems to answer the question before the edit. Can you re-read the clarified question and update your answer? Personally I think you made a very good point answering the previous question. $\endgroup$
    – Vylix
    Commented Aug 27, 2017 at 13:01
  • $\begingroup$ @Vylix in re-reading, it does not ask 'What do human bodies UNIQUELY produce/provide' nor 'more efficiently provide'. Thus, 'fertilizer' would be a by-product of slave labor - like composting food scraps, or re-cycling tires. So, generally, [link(en.wikipedia.org/wiki/Fertilizer) gives the nutrients plants need, and the human body provides them, but particularly nitrogen and carbon, as PiperChip stated. But only as a secondary byproduct of slave labor. There are other more efficient sources of these, but 'waste not, want not' let nothing go to waste. $\endgroup$ Commented Aug 27, 2017 at 15:24
  • $\begingroup$ "proscribed tasks" means forbidden tasks; do you mean "prescribed tasks"? $\endgroup$
    – Joshua
    Commented Aug 23, 2019 at 16:55

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