Soil test phosphorus and potassium
Last updated on January 15, 2021
Different laboratories use different chemical solutions, known as extractants, to determine soil test phosphorus (P) and potassium (K). These extractants lead to different soil analysis results on the same soil sample.
The current recommendations for soil testing in British Columbia are based on the Kelowna extractant, sometimes called the “Kelowna method.” If the lab you use follows a different method, their test results can be converted to equivalent results that would be obtained if the Kelowna method was used:
Results of soil testing should be used to determine the need for supplemental P or K for optimal crop growth. Consistent monitoring of crop growth, yield, and soil test results will aid in planning for P and K applications.
Learn more about soil P and K test methods here.
If agricultural operations with a land base of 2 hectares or more apply nutrient sources to land, post-harvest nitrate and soil test phosphorus results from within the last 3 years should be used to inform nutrient application rates. Details on the new soil testing requirements can be found here.
Contact information
AgriService BC
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Telephone: 1 888 221-7141
E-mail: AgriServiceBC@gov.bc.ca