ÖNORM L 1088

This Austrian Standard is used for the determination of "plant-available" phosphorus and potassium in soils with pH < 6 (determination according to ÖNORM L 1083, within CaCl2 solution). Excepted are soils used for forestal purposes. For soils with pH values >= 6, the CAL method according to ÖNORM L 1087 shall be applied. The DL method is preferred for soils with pH < 6, because this method partly extracts also apatites which are absorbed by the plant as nutrient from acidic soils. In case of photometric procedures, only orthophosphates are recorded, in the case of plasma emission spectrometry only total phosphates are registered from the extracted solution. In function of the reactive conditions during the photometric procedure, metaphosphates, pyrophosphates or polyphosphates are converted only partly into orthophosphates. When applying this ÖNORM, the general provisions of ÖNORM L 1053 shall be observed.