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A bimodal four‐parameter lognormal linear model of soil water repellency persistence
Author(s) -
Regalado C. M.,
Ritter A.
Publication year - 2009
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.7226
Subject(s) - soil water , log normal distribution , infiltration (hvac) , soil science , environmental science , organic matter , hydrology (agriculture) , mathematics , statistics , geology , chemistry , physics , meteorology , geotechnical engineering , organic chemistry
Soil water repellency may be characterized in terms of the delayed infiltration time of a water droplet resting on the soil surface, which is, water drop penetration time (WDPT), or repellency persistence. Such repellency persistence varies nonlinearly with soil water content (θ g ), although no models have been proposed to reproduce the variation of WDPT with θ g in soils. Dynamic factor analysis (DFA) is used to identify two common patterns of unexplained variability in a scattered dataset of WDPT versus θ g measurements. A four‐parameter lognormal distribution was fitted to both common patterns obtained by DFA, and these were combined additively in a weighted multiple linear bimodal model. We show how such an empirical model is capable of reproducing a large variety of WDPT versus θ g curve shapes ( N = 80) both within a wide range of measured WDPTs (0–17 000 s) and for samples with organic matter content ranging from 21·7 to 80·6 g (100 g) −1 . Copyright © 2009 John Wiley & Sons, Ltd.