Soil Horizon

[Adam_M]

I really tried to focus on OM additions in 2020 - I dropped 1/4" of peat moss twice and mulch-mowed as many leaves as I could get. When I pulled plugs for this year's soil test, I noticed there was quite a distinct horizon - it doesn't seem like the OM was making it into the root zone.

This particular plug was from an area where I experienced widespread dead grass over the summer so the grass on top is quite young - it was only planted in September.

...I know the soil test will be telling, but this isn't confidence-inspiring. Any suggestions on what I could be doing wrong here? And sorry that the photo is so blurry. I didn't realize that when I took the photo, but hopefully the horizon is still distinct enough to be useable for analysis.

[MorpheusPA]

That's fantastic and amazing, actually. You must have dropped a ton of OM to get that and should be happy with the results! What you see is called the O horizon, a horizon of undecomposed or not fully decomposed organic matter.

OM takes a long time to break down enough to infiltrate, and worms and other things that will take it deep take a while for populations to rise enough to carry it deeper. The earthworm in particular is not a rapidly-reproducing species without a food boom, which it's only had for a year now.

It'll get down there, but it takes time. Patience, grasshopper. By year three...you'll still have that O horizon, it'll be a little bigger, but you're realize the last two years decomposed even more and went deeper.

[Adam_M]

Well - Cool! I was concerned I overdid it.

[MorpheusPA]

Nope. One year, I applied 1,300 pounds of raw organic matter per thousand square feet. Corn, soy, leaves...everything I could find (mostly leaves, imported from everywhere after I had a good pre-emergent layer down).

The lawn glowed for more than a year. One literally, once one has an organic processing system in place, can't overdo it.

Except expect back and knee pain.