Use of Resin Disc Technique as a Reliable Soil Test For Measuring K Availability

The phytoavailability soil test (PST), a new approach of soil testing using resin sink is to simulate and determine the nutrient movement to plant roots in a more realistic and sensitive way than conventional soil analysis procedures. Response of PST method using cation exchange resin placed in contact with soil was tested for predicting potassium availability and uptake by a wheat crop at IARI farm. A linear relation of diffusive index (C√D) with K uptake rate of plant (R² - 0.966 and SE - 0.00003) was observed when the period of contact was more than seven days, thus showing the superiority of resin disc method as more realistic soil test of K availability and nutrient uptake by the crop at longer implantation periods.