Working primarily in an area around the Santa Cruz River and the Tortolita Mountains the researches uncovered check dams, terraces, rock piles and roasting pits indicating a level of Agave cultivation that I would have never guessed from a look at the modern landscape in the area:

The impressive scale of the large middle bajada rockpile fields is illustrated by the fact that they cover 485 hectares or over five square kilometers. Projecting numbers of rockpiles and meters of linear features from tabulated samples at representative fields, a total of 42,000 rockpiles and 120,000 meters of terraces and checkdams emerges. Experimental construction of features suggests that an initial expenditure of 50 man-years was required. Potential yields from the fields can he estimated by assuming one plant per rockpile and per two meters of linear feature, for a total of 102,000 plants at one time. With an average ten-year maturity for harvested plants, 10,200 agaves would have been available each year.

Source: University of Arizona - Desert Plants, Volume 7, Number 2 (1985) - Prehistoric Cultivation in Southern Arizona by Suzanne K. Fish, Paul R. Fish, Charles Miksicek and John Madsen. PDF.