Adding inorganic porous material to subsoil in heavy clay soil
posted 3 years ago
I have some of the worst clay silt soil in my area of Ohio. I also have maple trees with invasive root system.
To solve this I tried a number of solutions over a decade. One solution that I researched and tested over a number of years was using porous materials.
This started by finding some studies where fly ash was mixed in soils used on paths over a period of a decade or more.
They found that if the fly ash made up 20% or more of the soil mix they would not have a soil compaction problem.
I had hostas that I was testing in tree bags. My control plants usually died. I would amend with soil and add mulch every year.
What happened was the organic matter broke down over time and the soil reverted back to the average of the area.
To prevent this I added bottom ash in one area, perlite in another area, expanded shale in another area, and finally biochar in the final area.
I also put in plants in untreated areas.
In some other areas I amended with compost.
In all the treated areas the hosta did ok. In the untreated areas the hosta died.
In the compost areas the hosta slowly died. This was due to the root mass getting smaller and smaller as the roots got shallower and shallower.
I now double dig by amending the deep layer with just 20 to 30 percent porous material and adding compost and porous material to the top layer.
What is interesting is that if I amend with only porous I do not get a fish pond. But if I amend with too much mulch I get a fish pond with heavy rain due to poor drainage.