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Parameterization of the MACRO model to represent leaching of colloidally attached inorganic phosphorus following slurry spreading
Author(s) -
McGechan M.B.,
Jarvis N.J.,
Hooda P.S.,
Vinten A.J.A.
Publication year - 2002
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/j.1475-2743.2002.tb00051.x
Subject(s) - macropore , slurry , leaching (pedology) , sorption , filtration (mathematics) , lessivage , colloid , soil water , environmental science , porosity , environmental engineering , soil science , chemistry , hydrology (agriculture) , geotechnical engineering , geology , adsorption , mathematics , biochemistry , statistics , organic chemistry , catalysis , mesoporous material
. The dual porosity soil water and contaminant transport model MACRO was tested for its suitability to represent water flows and leaching of phosphorus (P) through field drains following spreading of slurry. These flows are characterized by very high loadings of P, including a high proportion in colloidally attached form, for about one week following winter spreading of slurry, followed by quite a rapid decline to the low background level. Use was made of the option in MACRO for representing colloid facilitated contaminant transport. The model simulates transport through macropores and soil matrix pores (micropores) of contaminant carrying colloids, as well as trapping of colloids by straining and filtration using an adaptation of standard filtration equations. Calibration involved selecting soil hydraulic parameters, colloid filtration coefficients and P sorption characteristics for two soils from measured and literature values. Both P in solution and P attached to colloids were represented in simulated outputs. Reasonable agreement was found between simulated and measured water and leached P flows. Work with the model suggests that macropore flow through the soil to field drains of colloidally transported P is an important component of water pollution associated with slurry spreading