Ultrasound method for extraction of phosphorus in soil

In the present work, an ultrasoundic procedure for the extraction of phosphorus (P) available in soil is described. The proposed method is based on extraction by 0.5 M sodium bicarbonate (NaHCO3), following with sonication under different conditions. Phosphorus was determined by the Murphy and Riley method. Sonication time and soil-extractant relative quantities were optimized. A statistical analysis approach was used to find suitable conditions for the ultrasoundic extraction. The main advantages of the sonication method are the reduced times of extractions, which take 10min in contrast to the 30 min required by a shaking method, and the possibility to reduce soil and extractant quantities from 5g-100 mL to 2g-40 mL. Performance of the method was evaluated, and the procedure was utilized to analyze soils from Santiago del Estero, Argentina.