Climate and choice of irrigation technology: implications for climate adaptation

Because studies of irrigation technology adoption often concentrate on small geographic areas with the same climate, few have estimated effects of climate on irrigation technology choice. This study examines the choice of sprinkler versus gravity-flow irrigation across 17 western states. Analysis considers long-term seasonal temperatures and growing season length. An erosion index captures effects of rainfall, field slope, and soil water-holding capacity. Sprinkler adoption increases with reliance on groundwater, pumping costs, farm wage growth, and erosion. Sprinkler adoption was significantly lower for smaller farms. In colder climates, climate warming may lengthen the growing season, but increase susceptibility to frost during the expanded growth period, which may encourage sprinkler adoption. In warmer areas, there is less scope to adapt to warming by switching from gravity to sprinkler technology. Sprinkler adoption declines monotonically in Spring/Summer temperature and growing-season-adjusted Fall/Winter temperature. A drier climate would reduce sprinkler adoption, while climates with more rainfall and more intense rain events would see greater adoption.