The last thing I will cover is plant diversity and adaptations. Arizona and California have extreme biological diversity, CA having at least 6,000 native vascular plant species and AZ having at least 4,500 native vascular plant species. Some of these species are extremely adapted to drought and desert climates. In fact some of these native species are the most drought hardy edible plants and plants in general in the world. To list a few productive food crops that can survive and even thrive in a Yuma, AZ climate.

-Tepiary bean and a multitude of other beans, most extreme food crop in the world
-Amaranth/quinoa species, a pseudo grain that can be used like a grain and is more nutritious and productive per acre than wheat
-Native American Mexican and Arizonan squash, both wild and cultivated species, some of which can thrive off of limited wet seasons or even survive the dry season with fruits.
-Native American corn varieties, it is thought corn first emerged near this region and exploded in diversity after domestication, some Arizona varieties can grow well in 6 inches of average rainfall.
-Wild legumes and aster species, including sunflower family root tubers and seeds, and plants like mesquite which have edible bean like seed that can also be used like wheat flour. Can also makes various herbal flower teas.
-Cacti fruit and paddles.

The typical planting strategy for natives was to plant them in dry washes where the water level was not too deep or to plant them in channels that would flood during the wet season. There were also completely dryland strategies. Wild mesquite forests could also feed thousands of people but required a great deal of harvesting and preparation effort. Crop rotation and legume planting cycles also regenerated soils rather than depleted them. It also helps that AZ has a large amount of desert loam and general riparian loam, but the montane areas of AZ have top class growing soil as well due to the long established forests.