Two-component transfer function modelling of flow through macroporous soil

The macropore and micropore domains of a soil system were considered to be hydraulically distinct. Drainage and solute transport through the soil were then characterized by mixed probability distributions. The components of t he mixed probability distributions were used to represent the distinct proc esses of drainage and solute transport in the macropore and micropore domai ns. A goodness-of-fit test showed that the lognormal distribution was the b est theoretical distribution for solute transport in each of the two domain s, while the two-parameter gamma distribution was best for drainage in each of the domains. A validation test showed that the mixed probability distri bution representation of the transfer function adequately incorporated dual porosity in the transfer function model for drainage and solute transport through macroporous soil. (C) 2001 Silsoe Research Institute.