Effect of water regimes on productivity, profitability and energetics of rice (Oryza sativa) cultivars under non-puddled conditions of Eastern India

The investigation was carried out to study the effect of various irrigation water regimes on productivity of different rice (Oryza sativa L.) cultivars under non-puddled establishment conditions during dry season (Jan-May) of 2014 and 2015 at Bhubaneswar. The treatment comprised establishment methods, viz. direct seeded rice (DSR) and non-puddled transplanted rice (NPTR); 3 water regimes, viz. no stress, 10 and 40 kPa; and 5 cultivars, viz. ‘Lalat’, ‘Sahbhagi Dhan’, ‘Arize^® 6129’, ‘US 323’, and ‘Arize^® 6444’. Experiment was conducted in 3 times replicated split-split plot design. Under no stress treatment irrigation was done as soon as the ponded water disappeared and in other 2 treatments, irrigation was given when tensiometer readings were 10 kPa and 40 kPa. Results showed that similar grain yield was recorded in DSR and NPTR. Higher grain yield was obtained under no stress (7.0 t/ha) followed by 10 kPa (6.2 t/ha) and 40 kPa (4.6 t/ha). Among the varieties ‘Arize^® 6444’ recorded maximum grain yield (6.6 t/ha), straw yield (7.6 t/ha) and harvest index (46.6). The DSR recorded the highest net returns ( 384, 000/ha), benefit: cost ratio (1.8) and economic efficiency ( 312/ha/day). ‘Arize^® 6444’ gave higher net returns and benefit: cost ratio under no stress condition. The nitrogen uptake, internal-use efficiency and partial-factor productivity was significantly high under no stress. In cultivars, ‘Arize^® 6444’ recorded the highest energy efficiency, energy productivity and profitability under no stress conditions. The result revealed that yield under no stress was on higher side, but irrigation savings with good yield was obtained under 10 kPa. Hence, ‘Arize^® 6444’ grown under DSR could be considered a better option in this area.