Determine the uses of Potassium
Water soluble and exchangeable potassium is readily available to plants. This is extracted with Morgan reagent (10% sodium acetate in 3% acetic acid solution) or 1M ammonium acetate (neutral). From the extractant, potassium is estimated by flame photometer. In the absence of flame photometer, turbidity method can be used. In this method the turbidity is developed by adding sodium cobaltinitrite and is measured with the help of a photoelectric colorimeter.