Evaluation of Closed-End Border Irrigation Accounting for Soil Infiltration Variability

This study assumes that the infiltrated depth of border irrigation follows a normal distribution, and the soil infiltration variability represented by the variability of infiltration coefficient ($k$) and final infiltration rate ($f_0$) are the Kostiakov-Lewis equation, which can be scaled in the same proportion. Then, a combination of variance method, validated from field-experiment data, is proposed to evaluate the closed-end border irrigation that accounts for soil infiltration variability. The results show that the normalization equation for estimating the infiltrated water depth is reliable. Accuracy of simulated advance and recession trajectories can be improved with soil infiltration variations being considered. The irrigation performance indications estimated using the proposed method are in agreement with the measured values and simulated values under the variable soil. Meanwhile, in terms of infiltration parameters variation, Christiansen’s uniformity ($CU$) is the most significant factor, followed by the application efficiency ($E_a$) and the storage efficiency ($E_s$), and resulting in 37.01, 15.22, and 15.24% decreases of $CU$, $E_a$, and $E_s$ when the variation coefficient of the normalization factor ($C{V}_F$) increased from 0.0 to 0.5. Therefore, the variability of soil infiltration must be considered when evaluating closed-end border irrigation.