<Arizona has a variety of soil structures including sandy, clay (caleche) and rocky. While this provides plenty of secondary and trace minerals initially, it does not provide the rich organic matter that retains water and provides primary nutrients, Compost must be incorporated into existing soil to create a constantly moist root environment for most plants.
Aeration must be maintained in a field/ garden either by mechanical or natural processes. Cutting plants off at the base and allowing the root mass to degrade naturally, as well as incorporating worms into the soil is a passive alternative to tilling.
Arizona soils are usually very alkaline and require decomposing material to increase acidity. Establishing a new garden with a ratio of 50/50 compost and native soil will provide initial nutrition for first year gardens(magnesium “epsom salt” application is usually all that is required mid season)
For established fields, yearly applications of Glacial rock dust, Indonesian Bat Guano, and a local source of organic nitrogen (such as manure or guano) should be all that is required to maintain a fertile field (Mg and calcium may be needed depending on crop and water source)
Gardening becomes much easier, and more enjoyable, when you work with nature rather than against it. Creating a hospitable environment for all the wonderful things living in your soil will make your garden healthy and balanced naturally. The way you do this is by avoiding salt based fertilizers (like miraclegro) which increase salinity and make all of your beneficial soil dwellers stress. Also, maintaining a constantly moist top layer of soil (by mulching or tight plantings) will encourage nematode and worm colonies to do the pest control and aeration work for you.
If you are a “crop specific” farmer, adopting sustainable farming practices can help you to establish and maintain regionally appropriate fungi and reduce water use. Incorporating root material from healthy plants post harvest allows new endo-mycorrhizae to colonize quickly. With groves/ orchards, ectomychorrzae can be collected from the area surrounding the root tips of healthy trees and used to innoculate new plantings.