Risk of Phosphorus Desorption from Canadian Agricultural Land: 25-Year Temporal Trend
- Eric van Bochove *ae,
- Georges Thériaulta,
- Jean-Thomas Denaultaf,
- Farida Dechmib,
- Suzanne E. Allairec and
- Alain N. Rousseaud
- a Agriculture and Agri-Food Canada, Soils and Crops Research and Development Centre, 2560 Hochelaga Blvd., QC, Canada, G1V 2J3
e current address: Agriculture and Agri-Food Canada, 1305 Baseline Rd., Ottawa, ON, Canada, KIA OC5
f current address: Ministère Développement Durable, de l’Environnement et des Pares, 675 René-Lévesque Blvd., Quebec, QC, Canada, GIV 5V7.Assigned to Associate Editor Goswin Heckrath
b Centro de Investigación y Tecnología Agroalimentaria (CITA), Gobierno de Aragón, Zaragoza, Spain
c Horticultural Research Center, Laval Univ., QC, Canada, G1K 7P4
d Institut national de la recherche scientifique, Centre Eau, Terre et Environnement, QC, Canada, G1K 9A9
Phosphorus (P) use in excess of crop needs may impact surface water quality and contribute to eutrophication. However, P loss from agricultural land to water has never been estimated at the Canadian national scale. In this paper, the risk of P desorption from Canadian agricultural land is assessed by the source component of the indicator of risk of water contamination by P (IROWC-P). The IROWC-P source component (P_source) characterized the mobilization potential of soluble P and integrated four models of P desorption by water for dominant agricultural soil series of Canada on the soil landscape of Canada polygon scale (1:1,000,000). The objective of our study was to describe and evaluate a standardized method for deriving the P_source component. The P_source was assessed over 5-yr intervals from 1981 to 2006 for scientifically based knowledge by relating annual P balance values, soil test P (STP) analyses, soil P saturation index, and Self-Davis water extractable P extraction values. Results show trends of soil P enrichment for most Canadian provinces over the 25-yr period but also an increased percentage of farmland classified above the water extractable soil P environmental threshold of 4 mg P kg−1. The Canadian Prairies and Ontario showed small P_source values and almost no farmland above the environmental threshold. Quebec and the Atlantic Provinces had P_source values that exceeded the environmental threshold in 2006; more than 33% of farmland is classified above the environmental threshold value.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2012. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.