I am working on a site that had geothermal installed on it. They left the soil horizons all in a tizzy and hardly anything has regrown in the space in 2 years. Can the B Horizon be remediated somehow by just adding a good soil mix on top or does it need to be removed and replaced with topsoil? Thanks for any feedback.
Location: Wellington, New Zealand. Temperate, coastal, sandy, windy,
posted 5 years ago
Are we talking a large area? What do you have in mind for the remediated spot?
I don't know much about geothermal, but it's not something I think of as having small-scale versions. Are there likely to be heavy metals present?
This level of damage is new to me, but a lack of actual knowledge never stopped me yet!
Has the topsoil been scraped off andcarted off, or is it mixed up with the subsoil?
I'd look at bringing in organic matter to build the soil rather than adding 'topsoil', which unless you're really careful is likely to be similar to the subsoil you're alreadyy dealing with
I'm assuiming the area's extremely compacted. It might be worth looking at a one-time soil aeration, the method depending on the size of the site.
Then I'd dump grass clippings, manure, old hay, whatever I could lay my hands on really, mixed with a few truckloads of chipped tree prunings.
I'd let let it settle for a couple of weeks then seed tough legumes, daikon, maybe pioneer legume trees and so on.
posted 5 years ago
Thanks Leila. I don't think anything was carted off the site, just all mixed up when they dug the vertical wells. It's over 1000 sq ft. Large enough...I don't think heavy metals are a concern but compaction certainly is.
I think we are going to go ahead with some aeration and lighlty tilling the top layer to incorporate some organic matter. Then we are building bermed beds for planting so the soil there won't be a problem.