中文摘要：

【目的】探讨两系和三系杂交水稻在实时实地氮肥管理模式下对氮素的吸收和氮肥利用率的差异。【方法】试验于2004和2005年在大田条件下,以两优培九、汕优63为材料比较研究了实时实地氮肥管理模式下不同叶绿素仪（SPAD）预设阈值对其吸氮特性与氮肥利用率的影响。【结果】水稻叶片叶色存在基因型差异,汕优63顶叶的SPAD值比两优培九平均低1.7～2.0个数值单位。在实时氮肥管理模式下,施氮量与SPAD预设阈值呈指数相关关系。对于汕优63而言,Nrate=0.9956e0.132SPAD（r2=0.8338＊＊）,对于两优培九则为Nrate=0.1565e0.173SPAD（r2=0.9508＊＊）。在SPAD预设阈值介于36～40的范围内,若要保持两个品种同一时期顶叶的SPAD值相同,汕优63比两优培九需要多施用氮肥37.3kgN·ha-1。【结论】在实时实地氮肥管理模式下,当氮肥平均用量接近160kgN·ha-1时,两优培九的吸氮能力、氮肥吸收利用率和氮素籽粒生产效率与汕优63相当;其氮素干物质生产效率、氮肥农学利用率高于汕优63;其氮素收获指数低于汕优63。此外,两优培九比汕优63表现出较高的耐肥抗倒伏能力。

英文摘要：

[Objective] This study was conducted to compare the most popular hybrid varieties, three-line hybrid rice, Shanyou63, SY63 and two-line hybrid rice, Liangyoupei9, LYP9, in their response to N application and fertilizer-N use efficiency under RTNM and SSNM in the field conditions in 2004 and 2005. [Method] The two varieties were grown under eight and six N treatments in 2004 and 2005, respectively, in Hubei, China. N treatments included a zero-N control, a SSNM and several RTNM with different chlorophyll meter （SPAD）thresholds. [Result] There was a significant difference in the SPAD reading between the two varieties. The SPAD reading of SY63 was 1.7 to 2.0 units lower than that of LYP9 at the same N treatment. Under RTNM treatments, total N rates were exponentially correlated with the SPAD thresholds. The equations for SY63 and LYP9 were, N rate=0.9956 e^0.132 SPAD （r2=0.8338＊＊）, and N rate=0.1565 e^0.173 SPAD （r2=0.9508.＊）, respectively. Additional fertilizer-N of 37.3 kg N·ha^-1 was required for SY63 to maintain the same SPAD value as that of LYP9 when SPAD thresholds were set between 36 and 40 under RTNM. [Conclusion] When N rate was around 160 kg N·ha^-1, LYP9 and SY63 had no significant differences in crop N uptake, N recovery use efficiency, or nitrogen use efficiency for grain production. However, LYP9 had higher nitrogen use efficiency for biomass production and agronomic N use efficiency than SY63. SY63 had higher N harvest index than LYP9. Under excessive N input, LYP9 demonstrated greater lodging resistance than SY63.