Objective  Effects of planting density and K and N applications on the yield and quality of hybrid rice, T-Liangyoumingzhan, were studied for cultivation optimization.

  Method   The “311-A” experimental design was applied for a regression analysis on the rice yield and quality as affected by planting density and K and N application rates. The value of each evaluation factor was set to be within the range of − 2, 2.

  Results   (1) By increasing the planting density in the range of 19.47-23.43 million clumps·hm⁻², the rates of brown and milled head rice were increased but the grain chalkiness reduced. Little effect was observed on the alkali dissipation and gel consistency of the rice. Hence, appropriate planting density would be conducive to desirable transparency and amylose content of rice. (2) Increased K benefitted the brown rice rate but lowered the alkali dissipation value and amylose content. It exerted no significant effect on the gel consistency of the rice harvested. Improved head rice rate, reduced chalkiness, and increased transparency could be achieved with adequate application of K at 71.0-95.5 kg·hm⁻². (3) Increasing N decreased the brown and head rice rates at first but increased as more N was applied. The addition of N at 177.0-200.2 kg·hm⁻² range could improve alkali dissipation, gel consistency and amylose content, but not significantly on chalkiness or transparency.

  Conclusion  Planting T-Liangyoumingzhan in the range of 19.47-23.43 million clumps·hm⁻² with the applications of K₂O at 71.0-95.5 kg·hm⁻² and N at 177.0-200.2 kg·hm⁻² was considered appropriate. Under which, a yield of 8 373.14-8 556.11 kg·hm⁻² Grade-3 high quality rice could be anticipated.