Developing ORYZA 1N for Medium- and Long-Duration Rice
2007
Swain, Dillip Kumar | Herath, Srikantha | Bhaskar, Burla Chandra | Krishnan, Prameela | Rao, Kurkuri Srinivasa | Nayak, Sangram Keshari | Dash, Rabindra Nath
There is a need to increase the rice production in nonwaterstressed rice-growing areas during the wet season in Asia by the use of a suitable combination of a medium- or long-duration variety and appropriate nutrient management strategy. The crop growth simulation model ORYZA 1N was used for variety selection and N optimization in nonwaterstress conditions. Selection was made from 12 released rice varieties of 115 to 150 d duration. The model was calibrated using input data from field experiments that were conducted during the wet season (June–November) of 2001 at the Central Rice Research Institute, Cuttack, India. In the medium-duration varieties (115–130 d), there was good agreement between simulated and observed leaf area index, biomass, and grain yield. The simulated biomass of long-duration varieties (135–150 d) showed large deviation from observed biomass at flowering. In the wet season of 2000, the model accurately predicted the grain yield, biomass, and leaf area index of medium- and long-duration varieties. When the ORYZA 1N model was used to simulate the effect of planting dates on rice yield, it predicted the decline in yield with late planting. It was recommended that farmers consider planting new variety Ranjit in the favorable lowlands that do not have water stress during the wet season and should apply 80 kg N ha⁻¹ in four equal splits at transplanting, active tillering, panicle initiation, and flowering. Technology verification trials of this practice conducted during the wet season of 2002 produced 5.51 Mg ha⁻¹ of rice, compared with 4.36 Mg ha⁻¹ grown with the conventional practices of area farmers.
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