I had a commercial apple orchard for over twenty five years in the Rio Grande Valley of central New Mexico and planted many trees by hand with a shovel. What a lot of work. We moved here to West Central Texas about a year ago. I am now planting apple trees using my 9 inch post hole digger.
The land I am using has never had as much as a hoe used on it and the ground was hard. I simply dig down about 3 or so feet with the post hole digger and make one hole as close to the other one as I can and put about 7 or 8 holes in a tight circle, pulling most of the dirt out. It really tears up the ground in this circle. Then, we have been putting in a lot of wet shredded paper, mulch and some peat (never any kind of fertilizer) and then covering the hole back up. We let that sit for a few weeks and then simply pull dirt out again with either a shovel or the post hole digger and plant the trees.
This has made planting trees easy for me...as I have gotten a lot older since I put in my orchard twenty five years ago...
I was also surprised at how loose the soil had become, how rich it looked and how the wet shredded paper had began to dissolve and become fertile matter...
Flattman