Dynamics of Potassium Fractions in a Calcareous Vertic Haplustepts Under AICRP-LTFE Soils

The application of FYM also maintained or increased potassium status of LTFE soils. In treatments of FYM (T₈ and T₉), the status of potassium fractions increased. There was overall decrease in available-K₂O status of LTFE soils after 8 year, except in treatments which received FYM (T₈ and T₉), where K₂O status of soil increased as compared to initial status. Water soluble-K also decreased in LTFE soil after a span of 8 years, except in treatments which received FYM (T₈ and T₉). Same results were also recorded in case of exchangeable-K, HNO₃ soluble-K, reserve-K and total-K, here also approved that for maintaining K fertility of soil at long run, it is essential to add organic fertilizer with inorganic ones for maintaining available potassium level in soil, application of organic manure is essential. In fact, all fractions of potassium decreased after a long run in intensive cropping of LTFE soils without addition of FYM. So it is alarming us to use organic fertilizer with inorganic one for maintaining K fertility status of soil in long run. At initial stage of experiment (1^st year) available-K₂O status of LTFE soils showed high category (> 280 Kg K₂O ha^-1), but after long run (8^th year) it decreased to medium category (140-280 Kg K₂O ha^-1), except in treatment of FYM application (T₈ and T₉), where increment in K₂O level was found rather than its depletion. Further it was established that, FYM is essential for maintaining soil fertility at long run. Similar results were also recorded in case of all other fractions of potassium.