Eventually the original broken thread question will get lost. Here is a link to it and the first response.

One might want to read that before reading the responses on this thread in order to maintain continuity.

Lloyd

I've noticed that the soil under a large pile, bin or windrow does not grow anything including weeds for quite some time.

In this picture, just beyond the compost with the tarp on it, there is bare patch of soil where nothing grows. One can almost see the straight line between the vegetation and no vegetation. Same with the area just under the green John Deere bin on the left. Both of those areas are where large windrows had been sitting.

Now this is purely speculation on my part but I think it may have something to do with lack of oxygen. The very active compost piles either 'sucked' the oxygen out of the ground or did not allow any oxygen into the ground. This then made the ground inhospitable for the soil organisms and thusly plants.

I have had tarps on the ground with curing compost on top and the weeds emerged shortly after the materials and tarp were removed so I don't think it was a sunlight issue. It seems to only be if the compost is directly on the ground.

So to tie it into the question, the soil might not change under a larger, active pile because there is not enough soil activity to do much incorporation of the composting OM into the soil.

I can't emphasize enough that this is just a WAG so be gentle.

Lloyd

Lloyd, WRT soil that won't grow weeds after a pile of active compost sitting directly on the soil; I suspect that the organic acids from unfinished/anaerobic compost may have soaked into the soil (oxalic, butyric, more). These acids inhibit seed germination and root growth.

I think you're right about oxygen being the issue.

It's just counter-intuitive that the soil didn't benefit from having compost piles sitting on them for 6 years. The lesson seems to be that thin layers, 3-4" max, of compost are what helps condition soil. As you say, access to oxygen may be the key, both for the micro-herd, and for the larger organisms such as arthropods and worms. The micro-herd would finish the composting, and the macro-herd would do the mechanical mixing of soil/compost.

Mine always stays clay and thats just how I like it the area my pile are in all the black dirt has been removed and the clay compacted so the piles are easy to work with equipment and I don't get runoff onto the river

But I better anser for most piles is a hot pile might not have many worms and not much air at the bottom for critters to work there

Also I am a firm beleiver that if you want clay to change and not just cover it up the organic matter needs to be worked in at least around here where the clay layer needs a pick axe to dig it why would any worms play there when there is a nice soft compost pile or black dirt on top to squirm in

The only way to change a clay soil into something that is workable is to add sufficient quantities of organic matter to that clay soil. Once you are close to having enough OM in any soil the earthworms will appear and start working, water will perculate into that soil instead of running off, and planting will be much easier and not require a pickaxe.