Phosphorus Extraction - Olsen Method
maggie.bowman
Abstract
The method is based on the extraction of phosphate from the soil by 0.5 N sodium bicarbonate solution adjusted to pH 8.5.
Steps
Print the required labels needed for Bray extraction for each site, depth, and replicate.
1000S_SITE_OLSEN_DEPTH_REPLICATE
1000S_SITE_Pext_OLSEN_DEPTH_REPLICATE
Weigh out 3gof soil into labeled 50mL centrifuge tubes.
For example: 1000S_PRS1_P_OLSEN_TOP_1
Add20mL of Olsen Extract solution (in cabinet under hood in 1521) using the pipet and electronic pipettor.
Cap the samples and shake to mix. Add samples to foam block on shaker.
Shake samples at 1rpm.
Centrifuge samples (using centrifuge on west side of 1521) for 4000rpm.
Pour off liquid into a clean and labelled 50mL centrifuge tube.
For example: 1000S_PRS1_Pext_OLSEN_TOP_1
Freeze samples on their side to prevent tube breaking in the -20°C freezer (Staging Freezer 2) bottom shelf if unable to filter immediately.
Follow sample filtering protocol below when ready to filter extracts.
