Influence of date of sowing and irrigation scheduling on rabi castor (Ricinus communis) in Peninsular India

A field experiment was conducted during rabi seasons of 2007–2010 at Regional Agricultural Research Station, Palem, Andhra Pradesh in order to study the performance of rabi castor (Ricinus communis L.) in relation to four dates of sowing (October 1, October 15, November 1 and November 15) and scheduling of irrigation at three CPE levels (50, 75 and 100 mm). Pooled data of three years revealed that sowing on October 1 significantly outyielded (2.32 t/ha) other three dates of sowing. With delay in sowing from October 1 to October 15, November 1 and November 15, bean yield of castor declined by 21.5% (1.91 t/ha), 24.1 (1.87 t/ha) and 44.1% (1.61 t/ha), respectively. Sowing on October 1 was found to be superior in respect of water use efficiency (3.73 kg/ha-mm), net returns (38.65 × 10³/ha) and B:C ratio (2.67). Among irrigation levels, scheduling of irrigation at 50 mm CPE resulted in higher bean yield of castor (2.00 t/ha) but found on par with 75 mm CPE (1.91 t/ha). Scheduling of irrigation at 50 mm CPE was found to be superior in terms of net returns (30.82 × 10³/ha) but B:C ratio was higher in case of 75 mm CPE (2.39). Higher water use efficiency was observed with 100 mm CPE (3.53 kg/ha-mm) followed by 75 mm CPE (3.50 kg/ha-mm) and the lowest was with wet regime (2.90 kg/ha-mm).