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Updated: Jul 13, 2026
06:42
Measuring Phosphorus Release in Laboratory Microcosms for Water Quality Assessment
Published on: July 22, 2019
Relationships between soil and runoff phosphorus in small Alberta watersheds
Joanne L Little1, Sheilah C Nolan, Janna P Casson
1Alberta Agriculture and Food, Conservation and Development Branch, 206, 7000, 113 St. Edmonton, AB, T6H 5T6, Canada. joanne.little@gov.ab.ca
Journal of Environmental Quality
|July 20, 2007
Summary
Field-scale soil test phosphorus (STP) strongly predicts dissolved reactive phosphorus (DRP) and total phosphorus (TP) in runoff. These findings are crucial for developing accurate phosphorus loss models in Alberta.
Area of Science:
- Environmental Science
- Soil Science
- Agricultural Science
Background:
- Field-scale relationships between soil test phosphorus (STP) and runoff phosphorus concentrations (dissolved reactive phosphorus [DRP] and total phosphorus [TP]) are critical for phosphorus loss modeling.
- Existing models often lack robust field-scale data, particularly under varying hydrological conditions.
Purpose of the Study:
- To establish field-scale relationships between soil phosphorus indicators (STP and degree of phosphorus saturation [DPS]) and runoff phosphorus (DRP and TP).
- To evaluate the impact of different soil depths and spatial representations of STP on predicting phosphorus losses.
- To assess these relationships under both spring snowmelt and summer rainfall conditions.
Main Methods:
- Monitoring runoff phosphorus concentrations (DRP and TP) from eight field-scale microwatersheds (2-248 ha) over three years.
- Analyzing soil samples for STP at multiple depths (0-2.5 cm, 0-5 cm, 0-15 cm) in spring and fall.
- Calculating the degree of phosphorus saturation (DPS) for the surface soil layer.
Main Results:
- Strong linear relationships (r²=0.87–0.89) were observed between site mean STP and seasonal flow-weighted mean concentrations (FWMCs) of DRP and TP.
- The predictive power of STP was consistent across the three soil layers analyzed.
- Extraction coefficients were comparable to other Alberta studies but higher than those from rainfall simulation experiments.
- The DPS relationship demonstrated similar predictive ability to STP.
Conclusions:
- Field-scale STP measurements provide a reliable basis for predicting runoff phosphorus losses in Alberta.
- The derived relationships are applicable across different soil layers and can inform phosphorus management strategies.
- These findings contribute essential data for refining regional phosphorus loss models.
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