Agriculture in the prehistoric Southwest
After the Hohokam disappeared, Spanish explorers of the 16th century noted the use of canal irrigation in only two areas of the Southwest: eastern Sonora, primarily practiced by the Opata and Lower Pima, and among the Pueblos of northern New Mexico. Irrigation by the Opata and Pueblos had different objectives. In Sonora, with a long growing season, two crops of maize a year were grown in river valleys. The spring crop during the dry season was dependent upon irrigation; the summer and fall crop during the rainy season utilized irrigation to supplement rainfall. The necessity of irrigation probably required a high level of social organization. In New Mexico, with only one crop of maize per year possible, irrigation was supplemental and the lesser dependence on irrigation implies less social organization than in Sonora.
Merlo Partido
Inside the haciendas the main economical activities were the agriculture and cattle-raising. The fertile land —drained by Las Conchas/Reconquista River— was covered with wheat fields and orchards. 
The bigger hacienda was granted to the Company of Jesus and the resulting production provided the Jesuits the financial resources to maintain the schools they had in Buenos Aires.