Horse manure compost for caliche soil (basically limestone rocks and clay)

We are finishing building our house and I am trying to figure out what to do about all the areas where we dug out things - nothing grows in there for 12 months as is thanks to caliche soil (limestones and clay). I got an offer from a local horse stable to haul away as much as I need horse manure "compost". The reason for quotes - when I came to check it out (before sending a dump truck to pick it up) - this is what I saw:





It did not look like compost to me. Is this would be usable? Should I apply it as a top dressing or till into the existing soil (clay mostly on the surface)? Should I dump it and keep composting, if so - for how long? (i am in central Texas). Any other ideas?

BTW, I did not grade the lot yet. As one option I think is to spread it before grading, and then cover with topsoil around the house. Would that be a good idea to put such compost below fill and topsoil? Or it is better to have it as a top layer?

My ultimate goal is to seed native Texas seeds (got these). While these should grow in caliche, germination would be tough due to lack of nutrients and constant washouts (lot is on the side of the hill)

I need to revive somehow about 20k-30k sqft...

Hi Joe,

My thoughts on the subject are use the mostly chip manure to do windrow composting, then once the chips break down just top dress your soil with a solid 8" layer. I wouldn’t bother grading the soil first unless its really uneven, since you'll be grading to spread out the compost once its finished. I wouldn't bother tilling either, but running over it first with a key line plow on contour may help water absorption.

You could try spreading out 8" layers of the mostly chip manure, which im assuming is mostly pine shavings, and inoculate it with Blewit mushroom spawn, to speed up the break down; then harvest some usable food stuffs or products for resale; however, that would take some shade and a water source. If they are hardwood chips you'll want King Stropheria spawn.

If you have a water source, Silver River Sweet Clover is a new released named variety of Sweet Clover, that has been spacifically bread for Texas soils like yours. It will help grow organic matter in your soil, fix nitrogen, provide shade and pollinator habitat, is decent grazing for livestock, and could be planted in rows wide enough to farm mushrooms or spread multch between while your growing/developing your soil biome.

Those are just a few thoughts, one other is windrow composting, and farming/free ranging chickens amongst your windrows to stir the compost and add there nitrogen rich manure to speed up break down.

Hope that helps!