Articles scientifiques



Type : Articles scientifiques
Auteur(s) : Goulet, M., J. Gallichand, M. Duchemin et M. Giroux
Année : 2006
Titre : Measured and computed phosphorus losses by runoff and subsurface drainage in Eastern Canada
Orientation : Proposer des pratiques culturales et des aménagements hydro-agricoles
Publication : Applied Engineering in Agriculture
Volume : 22
Numéro : 2
Pages : 203-213.
Résumé : Considering the difficulty in quantifying phosphorus losses from agricultural areas, index methods (PI) for predicting relative losses of phosphorus (P) to surface water have been developed in many regions of Europe and North America. This research was conducted to compare results of a PI model with measured values of P losses, to an adjacent watercourse, from nine 0.19-ha experimental plots monitored from January 2001 to December 2002. The experimental setup was located near Québec City, Canada, and allowed measurement of both surface and subsurface P losses. The 18 computed PI annual risk values (9 plots × 2 years) ranged from low to moderate. During the monitoring period, 98% of the water and 95% of the P moved out of the plots via the subsurface drainage system. P losses through subsurface drains represented, on average, 514 g total P ha-1yr-1 compared to 26 g total P ha-1 yr-1 by surface runoff. On average, 84% of the total P losses were under particulate form. A stepwise regression showed that only three of the ten PI model components (total P budget, soil erosion, and organic manure application) were responsible for 86% of the measured total P losses variations. The correlation between PI values and measured total P losses (r = 0.63) was significant at the 0.10 probability level. Fixing all PI components to a value of 1.0 increased the correlation (r = 0.73), indicating possible improvement of the predictive capability of the model through optimization of the weights.

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