Faculty of Agriculture, Annamalai University, Annamalainagar.
** Present address:—Central Plantation Crops Research Institute, Kayamkulam. Kerala, 690533.
* Part of the M.Sc. (Ag.) thesis submitted by the Junior author at Annamalai University in 1977.
A field trial was conducted to study the effect of application of organic amendments such as sesbania, glyricidia and farm yard manure on the persistence and dissipation of phorate in soil and rice plants. Phorate persisted in organic amendments applied soil for 40–60 days depending on the concentration of the chemical. On the other hand it persisted for more than 60 days in unamended soil. Phorate accumlation in rice plants increased upto 30 days after application and decreased thereafter. Phorate residue detected in grains was below the tolerance level at 1.00 kg. a i/acre rate but at higher concentrations, residue was above the tolerance level.
