Some people may think that an organic matter level of 6.3 percent is on the low end of the optimum levels of 6 to 10 percent. I'm not sure why but the levels of Phosphorus in my soil has gone from below optimum to above optimum just by adding compost and other forms of organic matter, no rock phosphate or anything else. The Phosphorus in synthetic fertilizers is rock phosphate that has been run through an acid bath to make the Phosphorus more soluble, readily available, which allows trhat Phosphorus to flow out of the soil with water and cause pollution in the lakes and ponds around you.
If you feel a great need you might consider adding rock phosphate at about 1/4 to 1/2 the level recommended and see what happens again in a year or so.

Ask the lab that did the test for you concerning what's appropriate for your soil/region.

I find this chart useful, you can pour in a nutrient, but if the ph is off, the nutrient can bind and become less available to the root hairs.

{{gwi:135844}}

So if your soil is a bit acid, I'd say wood ash can't hurt, if it's from clean wood and you mix the ash so it isn't just water-repelling clumps. But if you are already medium alkaline, the basic wood ash could push the ph to make P even LESS available, like I did in my coastal clay soils here in LA. I now use my wood ash as a bug repellent around flats and seedlings or I'll throw it on a compost pile, but I won't mix them in the ground again and I just use bone, blood, fish and seaweed meals.

Thanks dicot, that is a great chart for pH & availability. My pH is 6.6, and I think I want it to stay there, so no ash.

I was thinking of using cow bones (have a clean source) to supplement 1/4 of the recommended rock phoshate as kimmsr suggested. Though seems whether to crush or put the bones in the soil whole is an open question from those who do it...

Either way I have to figure out how to get it into the blocks, which will retain most of the sod (front yard). Sticking big bones in the ground sound as easy as digging holes in the sod and dumping rock.

Hey Midlin, I understand that using the rock phosphate in a banding method works well and is what I do. You should be able to get away with just a few bags of rock phosphate by putting a small concentrated layer of the stuff right up against the roots, which will accelerate the initial root growth of the trees nicely. (In the case of bare roots I have even heard of adding the rock phosphate to a liquid solution and dunking the bare roots in immediately before planting (along with beneficial nematodes)).

All the best to you with your orchard.

Buckwheat, chamomile, dandelions and lemon balm, among other plants, are very good at taking up phosphorus from your soil. You might try planting an assortment of plants that take up phosphorus around your trees, then just chopping them down and leave them there as mulch to decay and return the phosphorus to the soil in a more usable form.