Phosphorus Extraction - Bray Method
maggie.bowman
Abstract
The method estimates the relative bioavailability of inorganic ortho-phosphate (PO4-P) in soils with acid to neutral pH.
Steps
Print the required labels needed for Bray extraction for each site, depth, and replicate.
1000S_SITE_P_BRAY_DEPTH_REPLICATE
1000S_SITE_Pext_BRAY_DEPTH_REPLICATE
Weigh out 2gof soil into labeled 50mL centrifuge tubes.
For example: 1000S_PRS1_P_Bray_TOP_1
Add 14mL of Bray 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 1000rpm.
Centrifuge samples (using centrifuge on west side of 1521) for4000rpm.
Pour off liquid into a clean and labelled 15mL centrifuge tube.
For example: 1000S_PRS1_Pext_Bray_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.
