A simple method for evaluating the relative water uptake rate of drip-irrigated crops

Abstract

Drip irrigation is widely acknowledged for its water use efficiency, yet evaluating relative water uptake rates (RWURs, ratios between the water uptake rates and the irrigation rates) remains pivotal for effective system design and management. This article presents a novel method employing straightforward measurements of wetted soil surfaces around emitters or perpendicular to driplines, both with and without water uptake, emphasizing simplicity and practicality. The proposed method offers valuable insights into agronomic water use efficiency, facilitating the optimization of drip irrigation for both annual and perennial crops. While effective for intensively irrigated crops, the method does have limitations for smaller wetted areas and longer irrigation cycles, depending also upon a reasonable determination of the active root zone depth and the soil capillary length. Despite relying on a simplified water uptake model, the accessibility and cost-effectiveness of the method render it a valuable tool for assessing RWURs in diverse agricultural settings, contributing to the sustainable utilization of water resources in drip irrigation.