2.9. Estimation of NPK & pH using Lab Method
Testing of pH -
Weigh 10 g of dried soil in centrifuge tube. Add 25 ml of Distilled water to it. Shake the solution for 5 min and allow it to settle down the soil for 30min. Test the pH using pH electrode and meter.
Testing of Nitrogen (N) -
Nitrogen is tested using alkaline potassium permanganate method (Subbiah and Asija,1856)
Testing of Phosphorous (P) -
Phosphorous is determined by using Olsen's method.
Testing of Potassium (K) -
Potassium is determined by using Flame Photometer with extraction of K is done using neutral ammonium acetate