Analytes Certified for in 2020
This method is required to adjust soil chemical results based on air-dry samples to an oven-dry (105oC)
basis. When the air-dry moisture content (M%) is known, the correction from air-dry
to oven-dry is as follows:
Oven-dry result = [Air-dry result x (100+ M%)]/100
Exchangeable bases - 1M ammonium acetate at pH 7.0.
This rapid method for exchangeable cations in non-saline acidic through to slightly alkaline soils has no pre-treatment for soluble salts. It should yield similar data to those of method 15A1, except it can overestimate exchangeable Ca in soils containing calcium carbonate.
Soils are extracted with 0.005M DTPA, at a 1:2 soil:solution ratio, and shaken for 2 hr at 25oC. Analytical finish is either ICP-AES or Flame AAS.
Dry ashing without HF, and uptake in HCl. AAS-Flame finish, with pulsed hollow cathide lamp background correction, and using air acetylene.