Soil Remediation Questions (midwest.social)

submitted 1 year ago* (last edited 1 year ago) by Nemo@midwest.social to c/soilscience@slrpnk.net

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I'm in Chicago, on the West Side, with two adjoining lots of uncertain history.

The lot I live in had no garage going back several decades, but I pulled out a foundation for something smallish when I laid down sod after moving in; and when I dug the posts for the fence (and raised beds) I found not one but two brick patios, one about six inches down and one about eighteen inches down. Also a lot of garbage, car parts, old clothes, and plastic.

The second lot has a sunken area with a footprint the same size as my brick four-square. I don't know if the limestone foundation is still down there. We filled in the area with wood chips to keep down weeds and reduce the likelihood of falling into the hole.

Right now we're gardening in raised beds, but I'd like to get to in-ground planting eventually. What do I need to watch out for, what do I need to do, and what plants can I use to pull any heavy metals out of the soil over the next few years? I know sunflowers work if you get them out by the root, and that's great, but is there anything more low-profile or more physically manageable, especially something native to the area?

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[-] Track_Shovel@slrpnk.net 2 points 1 year ago

Yeah, structural soil (I'm assuming fill, is what you're talking about) with organic amendments is a good way to go too. They do that a lot on mines, since mines usually have dogshit soils, or a shortage of soil.

I suggested the modified hugelkulture (fuck I hate permie nomenclature) since you can use similar methods inside a raised bed box to craft your medium. The reason they have such a checkered history though is because people don't know enough about amendments, and often opt for primarily wood based amendments. Wood has mega high C:N ratios so their constructed soil systems end up nitrogen depleted really quickly depending on the particle size of the wood. Sidebar: never use sawdust.

[+] Treevan@aussie.zone 1 points 1 year ago* (last edited 6 months ago)

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[-] Track_Shovel@slrpnk.net 1 points 1 year ago

Your definition of fill is accurate, but it's me who is being obtuse.

What I mean to say, is subsoil (B or C horizon) and then improving that with amendments. You wouldn't want compacted stuff though. In mining they use overburden (C horizon below 1 m) and amend it. They will also use suitable tailings sand or waste rock.

What you described as structural soil is very similar to the composition of waste rock, though waste rock is not as well sorted. Generally it's in the medium to coarse gravel range.

The issue with high amounts of coarse fragments is that it tends to limit water holding capacity. However, I've seen reclamation (first hand) where they rough mounded (created a micro-hummocky landscape) that supported 10 years of tree growth.