A Decade of Irrigation Water use trends in Southwestern USA: The Role of Irrigation Technology, Best Management Practices, and Outreach Education Programs

Abstract

Irrigation water is crucial for farm operations in the world, with irrigated lands contributing about 40% to food and fiber production. In semi-arid regions such as the Southwestern United States, the demand for irrigation water has increased due to population growth, rising temperatures, and severe drought events in the region. Irrigation plays a vital role in the economies of southwestern states and requires comparative studies to understand the current situation and to propose possible improvement strategies. This study investigated the trend of irrigated cropland, the quantity of irrigation water use, irrigation technology, scheduling decisions, and irrigation outreach using data from 2007 and 2017 United States Department of Agriculture (USDA) National Agriculture Statistics Service (NASS) census. Harvested cropland in the region remained the same with minimal increase in total irrigated land (1%) and the quantity of irrigated water used (2%). However, gravity irrigation methods reduced significantly by 12%, with a 71% increase in the use of drip irrigation systems. The increase in the adoption of soil moisture sensors (55%), plant sensors (107%), government schedules (29%), and supplier’s schedules (50%) for irrigation scheduling decisions, did not translate to a reduction in irrigation water use at the regional level. However, at the state level within the same period, Arizona recorded an increase in irrigated cropland by 10% and harvested cropland by 9%, with a reduction in the quantity of irrigation water used (-5%). The gains in Arizona could be associated with the combined effects of improved irrigation technologies and the use of best management decisions, which could serve as a model for prudent water use in the southwest. There is a need to increase the effort in science-based education and extension programming on integrated approaches that emphasize both irrigation technology and the best management practices, which include seed selection for drought-tolerant crops.