Extraction method of available phosphorus and water soluble potassium in fertilizer

The invention relates to an extraction method of available phosphorus and water soluble potassium in fertilizer, in particular to a method for extracting available phosphorus and water soluble potassium in fertilizer by utilizing ultrasonic. The extraction method of the available phosphorus and water soluble potassium in the fertilizer of the invention comprises the following steps: preparing a sample to be tested; weighing the sample to be tested and placing the sample to be tested in a volumetric flask; adding extracting solution and mixing uniformly; and placing the volumetric flask in an ultrasonic device, and carrying out ultrasonic cavitation extraction. Compared with the prior art, the invention has the advantages that the available phosphorus and water soluble potassium in the fertilizer are extracted by utilizing the ultrasonic cavitation effect, thus the demands of rapid detection and cost reduction are met; and detection results are high in accuracy and conform to the international standard, and the extraction efficiency of the available phosphorus and water soluble potassium in the fertilizer are effectively enhanced.