Soil Evidence of Hohokam Irrigation in the Salt River Valley, Arizona

Abstract

Hohokam irrigation in the Salt River Valley modified the chemical and physical properties of soils. Of these modifications, the accumulation of silts and clays at the surface is most resistant to post-depositional processes. Surprisingly, evidence for prehistoric, irrigation-affected soils in the Salt River Valley is not well-documented. The apparent paucity of prehistoric irrigation signatures in modem soils may be due to inadequate sampling or to cumulative irrigation at most locations being insufficient to leave a persistent soil signature. A preliminary strategy for identifying prehistoric irrigation-affected soils is suggested.