Effect of time of sowing and nitrogen fertilization on growth and yield of castor in vertisols under rainfed conditions

A field experiment was conducted at Regional Agricultural Research Station, Nandyal during kharif 2012 to study the effect of time of sowing and nitrogen fertilization on growth and yield of castor in vertisols under rainfed conditions. The experiment was laid out in a split-plot design with three replications. The treatments consisted of four main plots (Time of sowing -II fortnight of June, I fortnight of July, II fortnight of July and I fortnight of August and four sub plots (Nitrogen levels:0,40,60,80 Kg/ha). Significantly highest castor bean yield was recorded with I F.N. of July sowing but it was at par with II F.N. of June sowing. Significantly lowest castor yield was recorded with I F.N of August sowing. Irrespective of time of sowing, increase in N fertilization from 0 to 80 kg/ha increased the castor yield significantly, highest being with 80 kg N/ha. Interaction effect of I F.N of July sowing with 80 kg of N/ha recorded the highest yield but was at par with II F.N. of July sowing at the same level of N. I F.N of July sowing with 80 kg/ha of nitrogen application recorded the highest gross and net returns and B: C ratio.