Impact of Nitrogen Application Rate on Rice Yield and Quality

  Objective  The stable rice yield and rice quality improvement were ensured by the amount of nitrogen (N) fertilizer.

  Method  ‘Huhan 61’ was used as the experimental rice in this study. The four N application rates (equivalent to pure N0, 100, 200 and 300 kg hm⁻², respectively) were designed to analyze the effect N application rates on rice quality.

  Result  The results showed that N fertilizer improved rice yields in the ranged of 5.2-9.0 t hm⁻² compared to the control without N application. In terms of rice, the protein content increased, while the amylose content, gel consistency and taste value of rice decreased with the increase of N application rate. In terms of soil, the NH₄⁺-N and NO₃⁻-Nconcentrations increased with the increase of N application rate; while the content of available phosphorus and available potassium decreased by 9.7%-45.5% and 23.3%-70.7% respectively. Amylose and protein were the key factors to affect rice quality. Statistical analysis showed that the protein content of rice was negatively correlated with the contents of NO₃⁻-N, available potassium and available phosphorus in the soil. While the amylose content was positively correlated with the contents of NO₃⁻-N, available potassium and available phosphorus in the soil.

  Conclusion  It is recommended that a soil application rate of 200 kg hm⁻² could be helpful for the balance between soil N supply and rice quality for ‘Huhan 61’ cultivation.