A New Insight Into Furrow Nonuniformity: Advance Data‐Based Evaluation and Implications for Infiltration Characterisation

ABSTRACT Precise estimation of advance parameters is essential for volume balance‐based methods used to estimate infiltration, evaluate efficiency and design furrow irrigation. A power function x = ptʳ is a common function relating the waterfront advancing distance ( x ) and time ( t ). Coefficients r and p are conventionally estimated using non‑linear least squares (NLS) or log‑transformed linear regression (LTLR), both highly sensitive to data outliers. A screening pair (SP) method was therefore developed to address this limitation for nonuniform fields. The method filters advance data pairs using physical and statistical criteria, achieving an advance time simulation comparable to the conventional methods. The SP method yields more consistent r estimates (coefficient of variations [CV]: 3%–9%) than conventional methods (CV: 3%–13%). Across furrows within a field, SP‐estimated advance coefficients simulated data produced a more consistent Kostiakov parameter ‘a’ (dimensionless exponent of infiltration decline over time) (CV: 6%–23%) than NLS (CV: 15%–38%) and LTLR (CV: 10%–29%). The necessity of the new method is more evident from the observed amplification: a 1% change in r results in a change exceeding 1.5% in ‘a’. The SP method, therefore, offers a robust alternative to conventional methods, producing physically consistent parameters for irrigation water management.