Silicon and organic manure influence on phosphorus dynamics in Alfisols of West Bengal, India

An experiment was conducted during 2016-2017 to evaluate phosphate fixation and release behavior in Alfisols of West Bengal, India under 5 prevailing land use systems viz., Fallowland, Forestland, Upland, Mediumland and Lowland, of the locality. Ten levels of Phosphorus (P) (through KH2PO4) were applied to the duly processed soil samples and incubated at room temperature (30 degrees C) for 96 hours after which the available soil P was estimated by Olsen's method. The P fixing capacity of the soils was then calculated. The effect of application of 2 levels of silicon (calcium silicate) (0 and 50 kg ha(-1)) and 2 levels of organic manure (FYM) (0 and 7.5 t ha(-1)) on P dynamics of these soils over a period of 120 days was also studied in a pot culture incubation experiment in Bidhan Chandra Krishi Vishwavidyalaya (BCKV), Mohanpur, Nadia, West Bengal. While the highest P fixation (75.01%) was observed under Forest land, the lowest was observed under Medium land (54.49%). The observed results indicated that P content of soil, irrespective of land use, increased by a whopping 125.89% up to 30 days of incubation and then started declining. Application of silicon and FYM resulted in significant increase (P < 0.05) in the available P content of the soil and silicon and organic manure had a synergistic effect increasing the available P throughout the incubation period. We conclude and recommend application of silicon and organic manure for increasing availability of P in these traditionally high P fixing Alfisols of West Bengal, India.