Irrigation plays a large and growing role in global agricultural production. In California, USA, irrigated agriculture is increasingly coming into conflict with competing uses; driven primarily by the frequent and severe droughts that plague the state. In agriculture, growers are turning away from inconsistent and irregular surface water resources to deep groundwater reserves for irrigation. However, as pumping rates outpace recharge rates, concerns about the sustainability of groundwater resources in the region come into question. In response, the state of California enacted the 2014 Sustainable Groundwater Management Act, mandating that sustainable groundwater management plans be developed for critical agricultural basins. Achieving such sustainability requires, in part, more efficient irrigation management, which is predicated on the accurate prediction and constant monitoring of evapotranspiration (ET). Satellite-based remote sensing technologies can be employed in mapping ET at field to sub-field scales, quantifying time- and space- varying crop water use and stress. To support efficient irrigation strategies, we investigate the utility of thermal infrared-based ET maps based on the ALEXI/DisALEXI modeling framework over a range of vineyards located throughout California, working in tandem with E&J Gallo Wineries to develop an operational toolkit designed to aid in irrigation management (as part of the GRAPEX project). We also explore the integration of satellite-based ET estimates into a data assimilation model (Vineyard Irrigation Data Assimilation; VIDA) to map soil water availability (i.e., root-zone soil moisture), a key component early in the season when growers are deciding when to begin irrigation.
Dr. Kyle Knipper
A Remote Sensing-Based Evapotranspiration Toolkit for Water Management Applications in Vineyards
U.S. Department of Agriculture- Agricultural Research Service, USA