My my, first visit to the forums in ages, and look what I find as the first post...
Well, let's deal with this from the top:
In one sense, I'm bumping this http://www.bay12forums.com/smf/index.php?topic=76007.0 pretty exhaustive thread, but also wanted to bring my own spin, which will probably include some points already made, but may also offer a good marriage of intuitive simplicity and fun/challenging complexity.
I think a big part of the crux of soil and ecology and its translation into human understandable/programmable language is the overwhelming complexity that unfolds when you approach the subject from a reductive/scientific pov. Here, I think it would help to focus on the basic foundational, modular/symbolic concepts upon which all living processes (plant and dwarf alike) are modeled.
That other thread is, itself, the result of long arguments over how to best achieve such a marriage of ease of use and gameplay depth. As was argued heavily in the thread itself, the thing is, a
complex program isn't necessarily
complex to the player. A good example would be something like Nintendogs, a game where the dog's behavior runs complex code to emulate realistic-looking dog behavior, but the player does not need to have any understanding of the code to understand that "the puppy likes it when you pet him". For an example within DF, itself, Worldgen merely takes a player hitting "start", although the game does have various extremely fiddly options if the player wants to dive into it. Toady even created a simple and complex interface for both types of players.
Basically, arguing over whether having 8 realistic attributes attached to soil or 4 "symbolic" or "simplified" attributes attached to soil will have far less dramatic impact upon the player than the actual interface through which the player has to interact with the data. That's basically why I spent most of my time running through how all those realistic systems could be
automated, such that, like with a Nintendog, all the player really has to do is tell their farming dwarves "turn this area into a plump helmet farm", the farm foreman comes back with "we will need [resources] to grow those plump helmets", and you can give them permission. If the player never has to understand anything further than that they need 5 more potash, and 10 more compost, then the actual nutrients or toxins in the soil can be performing multivariate calculus under the hood, and any random yahoo could still figure out that if they only have eight compost, they need two more.
To that end, arguing that there should be less simulation really only cuts into the depth of the game's simulation without actually achieving any benefit of simplicity for learning the game's mechanics. A lose-lose.
Rather than focusing upon the actual mechanics, I would recommend you focus upon the player interface, and how players should actually interact with their farms, and then work backwards from there into what systems produce the player interactions you want players to have. In my thread, I try to outline how players should interact with the system, such that they are mainly scheduling something that should be sustainable and kept on a repeating schedule year after year, not requiring player micromanagement except during the zoning of land and first setting of the schedule and when certain "events" occur, like blights or pest invasions that force player reaction.
Nutrients exist as a means of balancing desired outputs with the resources you possess to input. Toxins exist as a potential temptation for short-term payouts for long-term consequences, or as a long-term land reclaimation project that can make certain areas (say, salty land) more challenging.
As for whether or not to have realistic nutrients, I'd also like to point out that Toady's grandparents were farmers, he has an interest in soil science, and part of his goals for farming were to include the NPK model of macronutrients "to the extent the farming interface can provide decent feedback for you". Having pseudo-Greek philosophic takes on the carbon cycle just isn't the sort of thing Toady prefers.
Finally, don't be shy about actually resurrecting an old suggestion thread if you just want to rehash old material: It's generally preferred over starting a new topic, since you tend to have people who reiterate the same arguments already made and rebutted, which ultimately does nothing but waste time. (There's a reason why I just plain have links to common arguments so I don't have to keep making them over and over...)
Toady's pretty against modelling dwarf poop, because, IIRC, he doesn't want dwarf fortress to get a reputation for being "that game about dwarf poop". One way to model it without having poop directly would be to make it possible to herd livestock over fields after harvest/while fallow, and have that increase field fertility.
This is not really true. Toady has made many statements on the topic, and has moved far away from those initial outright rejections. See
this post from the Agriculture Rebooted thread for an in-depth counter-argument on why the nitrogen cycle should rationally be a part of the game.
To cut to the chase for the TL;DR types, however:
From a
Reddit article:
I like fertilizer, animal tracking and sewers. I dislike potty breaks. This is an example of realism that I think has a lot of potential for trouble. Potty breaks in adventure mode might be realistic, but there are immersion issues there. He he he, I mean in the sense of the player being kicked out of their groove. The other kind of immersion wouldn't be so bad, because sewers are common adventure environments. In dwarf mode, dwarves already take a lot of time out for self-maintenance, and this would be a more senseless kind, compared to something like eating.
I've already proposed solutions to the problem of "too many breaks", and think that "combined breaks" should be sufficient. Plus, designing sewer systems is just so cool...
The best non-magic explanation is magma. There's an entire magma sea. There are guaranteed passages generated between the cavern layers. Real organisms are known that can subsist off of volcanic vents. Creatures are capable of moving between cavern levels.
The days where you could pretend that DF was somehow a low-magic world are long-gone. There are no rational, scientific ways to say that somehow magma causes amethyst men -literal walking chunks of amethyst- to operate as a pseudo-living creature. There is absolutely nothing remotely close to shadow creatures coming from other dimensions to kill lone travellers at night in real-world science, much less transformations into night creatures. This is a world where forests have a sentient hive-mind spirit that can transform ordinary animals into anthropomorphized furries on their whims.
This is the post in the Agriculture Rebooted thread, and in a
dedicated Xenosynthesis thread.
Making farming based upon the management upon some sort of magical resource, even some sort of "ambient resource", such as having to continuously offer prayer and sacrifice to a healing goddess to restore an ambient amount of magical healing energy that healing herbs require to bloom, both makes perfect sense within the DF world and also makes for a rather interesting set of choices for players, as trying to farm those herbs would mean submitting to the whims of said healing goddess.