Determining a reasonable distance of collecting irrigation data for real‐time management of furrow irrigation

Abstract

AbstractOne basis for the real‐time management of furrow irrigation is to estimate the infiltration parameters and Manning roughness, which can represent the furrow condition as early as possible. Closed‐end furrow irrigation experiments were conducted on 45 fields on the Guanzhong Plain in Shaanxi province, China. The infiltration parameters of the Kostiakov equation and Manning roughness were estimated according to multipoint advance trajectory and upstream end water depth at four advance distances (50%, 60%, 70%, and 100% of furrow length; i.e., 0.5 L, 0.6 L, 0.7 L, and 1.0 L, respectively). The estimated infiltration parameter and Manning roughness were then input into WinSRFR to evaluate their effects on furrow irrigation and determine a reasonable distance for collecting multipoint advance trajectory and upstream end water depth. The results indicated that the estimated infiltration parameters and Manning roughness by multipoint advance trajectory and upstream end water depth at 0.6 L or later were highly consistent with the measured values. Except for the upstream end water depth, the mean absolute percentage errors between the simulated advance trajectory, irrigation performance, and applied water volume with measured values were lower than 10% for all furrow irrigation experiments. Therefore, the reasonable distance for collecting irrigation data should not be less than 0.6 L.