|Dry mountain canyon wash looking out on the desert below. Canyons such as this one are the gateways for nearly all soils in the Basin and Range.|
Knowing the above process is essential to understanding soil distributions in the Sonoran Desert. And knowing where soils are located is key to understanding the Sonoran Desert landscape. Both hydrology and plant communities are strongly defined by the desert soil. In a previous post on soil mapping we discussed generally how to locate soils in the landscape. In this post we will discuss specifically how to locate soils in the Sonoran Desert. Believe it or not, desert soils are complex in structure but relatively easy to map. The general rules that we discussed before apply in a rather neat fashion.
|The alluvial fan is circled in white in the below image. The canyon through which all the sediments came from for the alluvial fan is lined with blue.|
previous post on soil color), therefore upper bajada soils are red in coloration while younger lower bajada soils lack red coloration. The red coloration indicates the presence of caliche and argillic soil horizons in most cases (previous post on desert soil horizons). Upper bajadas will also have steeper slopes while lower bajadas will nearly be flat. Upper bajadas will also generally have rockier soils and fewer rocks will be present lower in the bajada.
|A lower bajada soil surface. This plant community is primarily Creosote. There are a very few cacti also present though. The deep roots of creosote prefer the absence of impeding caliche and argillic horizons upslope on the bajada.|