When we talk about food plots, one of the the things that gets driven home is to correct the Ph prior to doing anything else. Does that apply to planting apple trees? Is there a basic range it should be in?
6 to 7 would be a good range. Some soil test labs can also give you results tailored for apple and pear trees so you can see if there are other mineral deficiencies that could be an issue.
There are Ag Extension guidelines online for people planning new orchards. These address site selection and preparation. These would give you lots of think to think about.