Parameterization of the MACRO model to represent leaching of colloidally attached inorganic phosphorus following slurry spreading |
| |
Authors: | M.B. McGechan N.J. Jarvis P.S. Hooda A.J.A. Vinten |
| |
Affiliation: | Land Management Department, Environment Division SAC, Bush Estate, Penicuik EH26 0PH, UK;Department of Soil Sciences, Division of Environmental Physics, SLU Box 7014 750 07, Uppsala, Sweden;Centre for Earth and Environmental Science Research, Kingston University, Kingston upon Thames KT1 2EE, UK |
| |
Abstract: | Abstract. 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 |
| |
Keywords: | Models leaching phosphorus slurries application to land |
|
|