Energetics of important production factors for upland rice (Oryza sativa)

An experiment conducted during 1989 and 1990 revealed that timely sowing (]ast week of June), nutrient management (40 kg N + 30 kg P2O5 + 20 kg K2O/ha) and optimum weed management (2 hand-weedings at 15 and 30 days after sowing) increased grain yield, energy output, energy-use efficiency and energy productivity of rice (Oryza sativa L.) significantly. Use of improved rice variety did not influence either grain yield pr energy-use efficiency. Use of chemical fertilizer in the system decreased the energy productivity, though it had very high energy output. Timely sowing (which is anon-monetary input) of upland rice was the most important factor in increasing grain yield, energy output, energy-use efficiency and energy productivity followed by optimum weed management in the system.