CropManage online decision support tool for irrigation scheduling of vineyards

Abstract

CropManage (CM) is an online decision support service (DSS) developed by the University of California, Division of Agriculture and Natural Resources for assisting farmers with efficiently managing water and nitrogen fertilizer to match the site-specific needs of their crops. CM also allows growers to maintain records of fertilizer and water applications for each of their fields. Although originally focused on vegetable crops, CM was more recently adapted for vineyards. Irrigation recommendations are based on estimates of crop evapotranspiration requirement where the crop coefficient (Kc) is calculated daily and adjusted for canopy development, irrigation method, and water stress imposed by grower management.  Data from soil moisture sensors and flow meters can be automatically uploaded into the online application to allow farmers to compare their practices with recommendations. CropManage estimates of crop ET (ETc) were compared with eddy covariance measurements of actual ET (ETa) in vineyards in coastal California from 2019-2024. In addition, CropManage estimates of ETc were compared with satellite-based measurements of ETa from the OpenET platform (etdata.org). Applied water and soil moisture data were also monitored at the study sites. Mean absolute error and mean bias error of modeled dailycumulative evapotranspiration were computed with respect to the eddy covariance measurements and OpenET collected throughout the growing season. Results indicate that CropManage and OpenET both performed reasonably well for estimating ET for winegrape. Seasonal applied water totals were often less than ETc estimates and ETa measurements indicating that soil moisture storage in the root zone likely contributed to a significant portion of seasonal ETc.