Premium
Risk of Phosphorus Desorption from Canadian Agricultural Land: 25‐Year Temporal Trend
Author(s) -
Bochove Eric,
Thériault Georges,
Denault JeanThomas,
Dechmi Farida,
Allaire Suzanne E.,
Rousseau Alain N.
Publication year - 2012
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2011.0307
Subject(s) - environmental science , eutrophication , agriculture , soil water , agricultural land , phosphorus , hydrology (agriculture) , water quality , environmental protection , geography , soil science , nutrient , ecology , chemistry , geology , geotechnical engineering , archaeology , organic chemistry , biology
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.