Surveying the Southern Tucson Basin
Matt Pailes, Preservation Archaeologist and University of Arizona Graduate Student
The Hohokam of the southern Arizona desert are best known for their creation and management of extensive canal networks. In recent years we’ve come to realize that other agricultural technologies also played critical roles in sustaining Hohokam populations. My work with Archaeology Southwest investigates one such alternative strategy in the southern Tucson Basin. In a broad area surrounding the Zanardelli site, hundreds of rock clusters provide evidence that Hohokam farmers may have specialized in growing agave and other desert plants. These rock clusters date from A.D. 1100 to 1350.
In December 2007, I began our survey with the help of Archaeology Southwest volunteers Cherie Freeman, Bruce Hilpert, and Ken Fite. We’ve recorded detailed information on more than 4,000 rock clusters in an area of about 12 square kilometers. There are actually close to twice as many rock clusters in this area. Even so, our work has produced one of the most extensive data sets ever compiled on the agriculture infrastructure of dry farming. The insights we glean from these data will add much to our understanding of how the Hohokam thrived for centuries in the deserts of southern Arizona.
Many researchers believe that these rock clusters served to trap moisture and nutrients in the soil and prevent root destruction by burrowing rodents. By recording the location and size of these rock clusters, we can derive estimates about the productive capacity of this agricultural strategy, the amount of effort invested in creating dry farming infrastructure, and ecological relationships. In particular, we would like to know why Hohokam people stopped using rock clusters at around A.D. 1150, even though they continued to live in the area.