Changes

For BMPs including: [[bioretention]], [[enhanced grass swales]], [[vegetated filter strips]], [[absorbent landscapes]], [[green roofs]] and, bulk materials including: [[compost]], and [[topsoil]], phosphorus (P) should be measured as extractable phosphorus. Extractable P is the portion that is easily available to organisms like plants and algae i.e. is the measure of immediate concern to water quality.

For BMPs including: [[bioretention]], [[enhanced grass swales]], [[vegetated filter strips]], [[absorbent landscapes]], [[green roofs]] and, bulk materials including: [[compost]], and [[topsoil]], phosphorus (P) should be measured as extractable phosphorus. Extractable P is the portion that is easily available to organisms like plants and algae i.e. is the measure of immediate concern to water quality.

The quantity of extractable P is determined through acid or base extraction of a sample and testing the concentration in solution by a soil testing laboratory. Commonly used extraction methods on soil samples are the Bray and Kurtz P-1 procedure for non-calcareous soil <ref>Bray, R.H. and Kurtz, L.T. 1945. Determination of total, organic, and available forms of phosphorus in soils. Soil Science, 59: 39-45.</ref>or the Sodium Bicarbonate (Olsen) method for calcareous soil <ref>Olsen, S.R., Cole, C.V., Watanabe, F.S., and Dean, L.A. 1954. Estimation of available phosphorus in soils

The quantity of extractable P is determined through acid or base extraction of a sample and testing the concentration in solution by a soil testing laboratory. Commonly used extraction methods on soil samples are the Bray and Kurtz P-1 procedure for non-calcareous soil <ref>Bray, R.H. and Kurtz, L.T. 1945. Determination of total, organic, and available forms of phosphorus in soils. Soil Science, 59: 39-45.</ref>or the Sodium Bicarbonate (Olsen) method for calcareous soil <ref>Olsen, S.R., Cole, C.V., Watanabe, F.S., and Dean, L.A. 1954. Estimation of available phosphorus in soils by extraction with sodium bicarbonate. USDA Circular 939:1-19. Gov. Printing Office Washington D.C.</ref>.  

by extraction with sodium bicarbonate. USDA Circular 939:1-19. Gov. Printing Office Washington D.C.</ref>.  

The Olsen method is recommended as the default to use for typical Ontario soils <ref>Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). 2006. Soil Fertility Handbook. Publication #611. Toronto, Ontario.</ref>. Calcareous soils are mostly or partly composed of calcium carbonate (i.e., lime or limestone). The Olsen extraction method should be used if the soil contains more than 2% calcium carbonate <ref>Frank, K., Beegle, D., Denning, J. 2012. “Phosphorus” In Recommended Chemical Soil Test Procedures for the North Central Region. North Central Regional Research Publication No. 221. Missouri Agricultural Experimental Station.</ref>

The Olsen method is recommended as the default to use for typical Ontario soils <ref>Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). 2006. Soil Fertility Handbook. Publication #611. Toronto, Ontario.</ref>. Calcareous soils are mostly or partly composed of calcium carbonate (i.e., lime or limestone). The Olsen extraction method should be used if the soil contains more than 2% calcium carbonate <ref>Frank, K., Beegle, D., Denning, J. 2012. “Phosphorus” In Recommended Chemical Soil Test Procedures for the North Central Region. North Central Regional Research Publication No. 221. Missouri Agricultural Experimental Station.</ref>