Soil Test Based Fertilizer Requirement for Specific Yield Targets of Castor in Vertic Ustocrepts

Based on field experiment conducted on a Vertic Ustocrepts with castor (GCH-6), by dividing each of the four fertility strip into 12 subplots which received 9 selected treatment combinations out of 5 levels of N (0, 25, 50, 75, 100 kg ha^-l), 5 levels of P₂O₅ (0, 25, 50, 75, 100, kg ha^-l) and 4 levels of K₂O (0, 30, 60, 90 kg ha^-l) with 3 control treatments, fertilizer prescription equations were calculated. The results of field verification trials, conducted at different locations showed that yield targets were achieved below ± 10 per cent variation except 40 q ha^-1, but adjusted fertilizer prescription equations were fitted at yield targets of 20 and 25 q ha^-1 seed yield of castor. The highest return was obtained in yield target 20 q ha^-1 followed by 25 q ha^-1.