County extension office I'm assuming they test in Arizona

Midwest labs

https://www.midwestlabs.com/soil-testing-packages/

Recommend S3C with recommendations. Recommendations are for commercial users so not of great use, but for $1 more useful enough.

You can add individual tests if you desire.
https://www.midwestlabs.com/individual-soil-analysis/

You have to do a one time registration (even if only are going to do a single sample) before you can submit. After that you have an account for life. Can elect to read results online, have them emailed to you and/or mailed.

Fast, cheap and to the best of my ability to determine ... accurate.

https://www.midwestlabs.com/soils-memos/

Here is a link that might be useful: Midwest Labs

This post was edited by Fascist_Nation on Tue, Oct 7, 14 at 14:20

Excellent! Thanks for your help.