v0.31 Talk:Soil

I was under the impression that it was NOT a bug that you couldn't plant on dry underground soil.

ARGH

It's a bug, but Toady would rather focus on more important things than it. It may now be a feature, considering that it's been 11 updates and he hasn't touched it. [PREFSTRING: haunting moos] 11:59, 6 September 2010 (UTC)

Underground plants on dry soil

From what I've observed, underground trees and shrubs will only grow on dry subterranean soil if one of the two following conditions is satisfied: 1. there is an unmined soil wall within a 2 tile radius on the Z-level beneath the tile in question (just like how willow trees will only grow within a 2 tile radius of a river/brook/murky pool tile on the Z-level below); 2. there is a muddy tile within a 2-tile radius on the same Z-level (e.g. right next to your muddy farm plots). I first observed this behavior back in 40d and it still seems to be working this way in 0.31. --Quietust 17:45, 11 September 2010 (UTC)

I've wondered at that. I'll have to check with my current fort. --Kwieland 20:23, 11 September 2010 (UTC)

I have a single Z level that is one level below outside (Z-1). Half of it has plants/trees growing all over it, the other half doesn't! The Z-2 level is uniformly un-mined. There is an aquifer, but it doesn't correlate with the no plants area. It could be that under this area is non-soil, but I don't think so. Also, I've noticed that if I level down some hills outside, sometimes the trees grow back, sometimes they don't. Doesn't matter wether there is soil below or not.--Kwieland 20:19, 10 October 2010 (UTC)

Don't just assume that there is or isn't soil underneath - run reveal (ideally in a savegame copy) and check it directly. --Quietust 04:23, 11 October 2010 (UTC)

I currently have a fort with four soil levels. So far, the first three have plants growing on them, but the bottom doesn't, which follows from your first criteria above. Do you know what would happen if I mine out all the soil Z levels? Would all the plants stop growing, even on previously allowed spots? So if I want an extensive tree farm, I need to flood levels?--Kwieland 16:04, 12 October 2010 (UTC)

In all likelihood, the plants would stop growing except along the very edges (since those would still have soil nearby beneath them); existing plants would probably stay alive, but once harvested I doubt they would grow back. It might be worth doing some long-term experiments with a test embark to verify just how much of this is correct: embark in a region with at least 3 soil levels, dig out a 9x9 block on three Z-levels while leaving the center tile unmined on the middle level, then do the same thing in another room except with a single tile of mud instead of the unmined soil wall (muddy the whole room, then build unpaved roads to clean up all of it except the center tile), then dig down to the caverns and seal the rooms off for several years. --Quietust 17:51, 12 October 2010 (UTC)

I've started an experiment as described above, though with 11x11 rooms so that there will actually be a plant-unfriendly band in the middle. I dug out the rooms as described above (complete with the 1 tile of mud in one) and have sealed them off. My dwarves do not require food, drink, or sleep, and they have no emotions so there should be no danger of tantrums; as an added bonus, the Dwarven civilization from which they embarked is dead, so there's no migrants or caravans to worry about either. Three years in, the pattern seems to be holding true - the upper and middle rooms have plants growing 2 in the outer 2 tiles of each room (the bottom room is immediately above stone), the soil column is supporting plants above it in a 2 tile radius, and the mud tile is supporting plants in a 2 tile radius on the same level (though so far it's only sprouted plants exactly 2 tiles away, not 1 or 0, but that could just be due to randomness). --Quietust 19:29, 12 October 2010 (UTC)

After about 8 years, the plant growth seems to have capped - seemingly, a lack of mud limits the density of plants that can grow in an area.

            Z-0
░░░░░░░░░░░░░ ░░░░░░░░░░░░░
░:τ≈≈≈:≈≈≈:≈░ ░:::≈≈≈≈≈≈≈≈░
░::≈≈≈≈≈≈:≈:░ ░:≈:≈≈::≈≈τ≈░
░≈≈.......≈≈░ ░:≈.......≈≈░
░τ:.......≈≈░ ░≈≈.≈≈≈≈≈.≈≈░
░≈≈.......:≈░ ░≈≈.:≈:≈≈.≈:░
░≈≈.......≈≈░ ░≈:.≈≈≈≈:.≈≈░
░:≈.......≈≈░ ░♣≈.::≈≈≈.≈:░
░≈≈.......≈≈░ ░≈≈.≈≈::≈.≈≈░
░≈≈.......:≈░ ░≈≈.......≈≈░
░::≈:≈:≈≈:≈:░ ░≈♠≈≈≈≈≈≈≈≈τ░
░≈:τ≈≈≈:≈≈≈≈░ ░≈≈≈≈τ≈≈τ≈≈≈░
░░░░░░░░░░░░░ ░░░░░░░░░░░░░

            Z-1
░░░░░░░░░░░░░ ░░░░░░░░░░░░░
░≈≈≈≈τ≈≈≈≈τ≈░ ░τ≈≈≈≈≈≈τ≈≈≈░
░τ≈≈≈≈≈≈≈≈≈≈░ ░≈≈≈≈:≈≈≈≈≈≈░
░≈≈.......≈≈░ ░≈≈.......≈τ░
░≈≈.≈≈τ≈≈.:τ░ ░τ:.......≈≈░
░τ≈.≈≈≈≈≈.≈≈░ ░≈≈.......≈≈░
░≈≈.τ≈M≈≈.≈≈░ ░≈≈...░...:≈░
░≈≈.≈≈≈≈≈.:≈░ ░τ≈.......≈≈░
░≈≈.≈:≈τ≈.≈≈░ ░≈≈.......≈≈░
░≈≈.......≈≈░ ░≈≈.......≈≈░
░≈τ≈≈≈≈≈≈:≈:░ ░τ≈≈≈≈≈≈≈:≈:░
░≈≈≈≈≈♠≈≈≈::░ ░≈≈≈≈τ≈≈≈≈≈τ░
░░░░░░░░░░░░░ ░░░░░░░░░░░░░

The "M" tile is muddy, and the "≈" tiles denote where I predicted plants would grow. Further tests are definitely advised, but I forgot to turn off childbirth so I've got an increasing population of children accumulating, enough to trigger strange moods and insanity (I've got several dwarves running around babbling, but they never starve - eventually one will go berserk, and then it'll be over). --Quietust 20:25, 12 October 2010 (UTC)

After clearing the areas out and starting over, I was able to get plant growth within 1 tile of the mud. All in all, this looks to be confirmed, but others are certainly welcome to repeat the experiment. --Quietust 20:48, 12 October 2010 (UTC)

Are you sure this depends on the caverns being discovered?--Kwieland 18:28, 15 October 2010 (UTC)