Reagents
0.5M NaHCOV 3 (enough for 50 samples)
In 2 l volumetric flask
- 84 g Sodium Bicarbonate
- Adjust pH to 8.5.
- Bring to volume with DI water Keep refrigerated for a month.
Procedure - Total bicarb P
Soil solution extraction (1:20 dilution)
In a 50 ml Oakridge centrifuge tube
- 2 g Oven-dried equivalent field fresh, sieved soil
- 40 ml 0.5M NaHCO 3
- Shake for 18 hours on an angle Centrifuge @ 2500 rpm for 5 minutes.
- Decant into 15 ml centrifuge tube.
- Analyzing for P on ICP-OES for total bicarb P
Procedure - Inorganic bicarb P
In a 15 ml centrifuge tube
- 5 ml Solution (draw off before analyzing for total bicarb P)
- Slowly add 2.5 M H 2 SO 4 (expect effervescences) to neutralize the solution. Record the amount added to determine dilution. Test with pH paper.
- Vortex after ~2 minutes to de-gas the sample.
- If necessary, centrifuge @ 2500 rpm for 5 minutes.
- Analyze for inorganic P using the ascorbic acid method.
- Organic bicarb P = Total bicarb P - Inorganic bicarb P
Created: 12/17/08 Revised: 10/10/11