Field evaluation of an explicit infiltration function for conventional and alternate furrow irrigation

Abstract

Surface irrigation models should take two‐dimensional infiltration of water in furrows into account for better representation and more accuracy. The Warrick–Lazarovitch infiltration model (W–L model) has been proposed to estimate the two‐dimensional infiltration of water in furrow irrigation. This model consists of several parameters, including γ as an empirical parameter, which is often obtained through calibration of the model. This study aimed to evaluate the W–L model performance in determining the cumulative and lateral infiltrations under conventional furrow irrigation (CFI) and alternate furrow irrigation (AFI) schemes and two different initial and boundary conditions. The results indicate that the W–L model adequately estimated the cumulative and lateral infiltration, and the two‐dimensional infiltration was estimated with less error than the lateral infiltration. In both irrigation schemes, for an increased surface boundary head from 5 to 10 cm and for a reduced initial water content from 0.21 to 0.16 cm3/cm3, the value of γ would increase. Generally, γ values in AFI were greater than those in CFI. The W–L model estimated the two‐dimensional infiltration with more accuracy than the relative lateral infiltration for both CFI and AFI. Proper representation of infiltration is important in both irrigation management and in tracing footprints of chemicals used in agriculture.