Hugels are Dug, Time to Add Minerals to Subsoil?

Hello,

My yard is full of deep clods of clay, getting rained on and waiting for completion.

As I finished turning up all these clumps, I looked around and realized I didn't remove the top layer of better soil. It's still attached to the clay silty hard sub soil. But, since I'll be shoveling the dirt back on one shovel at a time (not with an excavator), I will be able to pick out the nicer top layers to add to the top.

Meanwhile, I wonder if now is the perfect time to add lime and an N-P-K mix to the hard sub soil?

The fact is, in some cases, this hard clay will be rather deep on top of the wood. Is this not a concern? Will the soil amendments help soften the clay?

Here is the layering:

Straw - 3" dry
Compost - 1"
Upside down grassy top soil - about 6"
Clay sub soil - about 12"-16" (hardened by rain and sun)
Grass clippings and/or horse manure
Wood logs
6"-20" deep trench (depending on the contour elevation) X 4-5 feet wide

It's possible the addition of the wood logs will spread out that clay sub soil layer (and all the layers for that matter) to a decent extent (I'm no math guy to figure the inches) - or should I remove some of it? Or is it okay? I've read the Ruth Stout straw method and the Back to Eden method are able to soften up poor soils. Is this all that's needed? I have accounted for some straw on top as mentioned above...and have access to unlimited woodchips if need be...

Meanwhile, again, I also wonder if this isn't a perfect opportunity to integrate the soil amendment recommendations given by the soil lab. I will call them to find out, but what does permies say on this? Shoveling starts Saturday...

I had 5 soil tests done around our 20 acres.

The lower field has little top soil and I sampled that. I also sampled a hugel bed we dug in the lower field 18 months ago which had mostly clay sub soil turned up on top, exposed. This clay subsoil, I believe will be very similar to the clay in our yard project mentioned above. So, here is the report on that hugel clay sub soil from the lower field:

OM = 1.4%
Bray-1 P = 4
K = 194
Mg = 245
Ca = 950
Na = 13
pH = 5.2
Buffer = 6.6
CEC = 12.1
%K = 4.1
%Mg = 16.8
%Ca = 39.1
%H = 39.5
%Na = .5
S = 18
Zn = 1.5
Mn = 33
Fe = 8
Cu = .6
B = .2
Soluble Salts = .1

Recommendations lb/1000 sq ft:
Lime 110
N = 4
P = 7
K = 0
S = 1

^^that is the consistency of the clay clumps in my yard now, I believe, approximately.

Here is the report on the top soil in my yard where the hugel project is underway:

OM = 2.1%
Bray 1 P = 11
K = 80
Mg = 265
Ca = 1750
Na = 20
pH = 7.4
Buffer = n/a
CEC = 11.3
%K = 1.8
%Mg = 19.6
%Ca = 77.8
%H = n/a
%Na = .8
S = 6
Zn = 2.9
Mn = 86
Fe = 32
Cu = 1.5
B = .3
Soluble Salts = .1

Recommendations lb/1000 sq ft:
Lime = 0
N = 4
P = 6
K = 6
S = 1