Validation of Target Yield based Fertilizer Prescription for Rabi Castor in Alfisol

Field experiments were conducted from 2015-16 to 2017-18 on a Typic Rhodustalfs (Alfisol) soils of Telangana at Regional Agricultural Research Station, Palem, Nagarkurnool, Southern Telangana Zone, India to validate targeted yield based fertilizer prescription equations which developed for hybrid castor by adopting eight treatments viz., Blanket recommendation (100% RDF:80:40:30 kg N, P2O5 and K2O ha-1), Blanket+5 t ha-1 of vermin-compost (VC), STCR-Target yield with NPK alone at 25q ha-1, STCR-Target yield with IPNS at 25q ha-1, STCR-Target yield with NPK alone at 30q ha-1, STCR-Target yield with IPNS at 30q ha-1, Farmer’s practice (40:20:0kg N, P2O5 and K2O ha-1) and Absolute control (without inorganic and organic fertilizers). The findings of these test verification trials clearly revealed that the percent achievement of the aimed yield target was within + 10 percent variation confirming the validity of the equations. Using STCR-NPK@25 and 30q ha-1 recorded significantly higher seed (20.74 and 22.30q ha-1) and stalk (24.63 and 26.36q ha-1) yield over blanket recommendation (19.40 and 23.13 q ha-1), while STCR-IPNS at 25 and 30 q ha-1recorde relatively higher seed (20.98 and 22.69q ha-1) and stalk (25.88 and 27.13q ha-1) yield over STCR-NPK alone treatments. The magnitude of built-up was higher with STCR-IPNS treatments as compared to STCR-NPK alone, blanket recommendations, farmer’s practice and absolute control.