『Abstract
Modern agricultural production uses phosphorus (P) extensively
to meet the challenges of feeding rapidly growing population and
changing lifestyles, making P a leading source of impairment for
rivers and streams in Canada. Developing effective management
strategies to reduce P losses from agro-ecosystems requires improved
understanding of P transport pathways in the soil. The purpose
of this study was to investigate vertical distribution and transport
processes of phosphate (PO4) in reconstructed
soil columns using HYDRUS-1D model. Results obtained from field
experiments were used to calibrate and validate the HYDRUS-1D
model. The results showed that 98% of the total P applied was
concentrated in the top 0.2 m of the columns, and decreased progressively
with soil depth. The model over-predicted PO4
adsorption, leading to a weak correspondence between the simulated
and the measured results for PO4. This is
a suggestion that the HYDRUS-1D model could not account accurately
for the different soil structures found in the undisturbed soil
columns and the preferential flow that occurs in these columns.
This may be due to the fact that Freundlich isotherm, which is
part of the transport equations, could not adequately describe
PO4 adsorption onto the soil particles.
Keywords: HYDRUS-1D model; Freundlich isotherm; Calibration; Validation;
Phosphate adsorption; Phosphate modelling』
Introduction
Experimental methods
Field description and experimental set-up
Sample collection and analysis
Simulations and calibration of the model
Assessment of the model performance
Results and discussion
Summary and conclusions
Acknowledgments
References