Abstract

                                The comparative mineralisation effect of Urea formaldehyde (UF), Tarcoated urea (TCU) and Lac coated urea (LCU) was studied in the predominant soll series of Cholavantin basin tract of Tamil Nadu under two moisture regimes. The results showed that after 4 days of Incubation, the amount of urea was the lowest in the treatment receiving urea in all the soils and the two moisture regimes. The amount of urea released from LCU and TCU Immediately after application in solls was quite high. The rate of release of urea-N from UF was the highest In all the soll series. The amount of NHLAN found in solls treated with different fertilizers was In the order Uren TCU LCU UF. The conversion of NII4 to NO2 and NOy form with urea was rapid in the case of Padugal and Analyur series particularly in 75% WHC moisture regime. The rate of decomposition of all the fertilizers is more in Palaviduthi series, whereas in padugal and Analyur series It is slow and incomplete.

Key words : Mineralisation, Slow Release Fertilizers