Central Mango Research Station, Lucknow
Availability of exchangeable versus difficulty available forms of potassium for mango have been compared. Ammonium acetalte and Morgan's reagent gave significant and consistent correlations in all the three depths whereas H2SO4 resulted into practically no correlations with leaf blade-K, it seems that mango inspite of being a tree crop has a preference for exchangeable-K. Leaf blade seems to explain the variability of soil-K in a better way as compared to petiole. Among the two reagents Morgan's extractant was found superior to Ammonium Acetate. By comparing the partial regression co-efficients of various depths, relative contribution of the first depth was found to be lower than those of other two depths.
