不同时期三系杂交稻主栽品种对氮肥用量的响应

以16个不同时期三系杂交籼稻主栽品种(育成时间1976-2006)为材料，通过0 kg hm⁻² (CK)、135 kg hm⁻² (N1)、255 kg hm⁻² (N2) 3种氮素水平试验，研究施氮量对其氮素利用、积累和转运特性的影响。结果表明：(1)早期 (1983年前育成)和中期(1983-1993年育成)品种对氮肥反应比近期(1993年后育成)品种敏感。增施135 kg hm^-2 (N1)氮肥使早期品种产量大幅提高，而近期育成品种在施氮量255 kg hm^-2 (N2)时产量才明显增加。(2) 施用氮肥增加水稻植株的氮积累量，增施135 kg hm^-2 (N1)氮肥时各品种植株各部分含氮量的增幅相近；增施255 kg hm^-2 (N2)氮肥时，早期品种氮同化量的增加主要在开花前，而近期品种主要在花后至成熟期间，施氮量对早期品种茎叶的氮转运率无影响，却显著降低近期品种的氮转运效率。(3) 当施氮量由135 kg hm^-2 (N1)上升到255 kg hm^-2 (N2)时，早期品种的氮肥农学利用率、偏生产力、吸收利用率和生理利用率均下降，而近期品种氮肥的农学利用率、吸收利用率上升，生理利用率基本保持不变。(4) 相关分析表明，氮的农学利用率、氮偏生产力、氮肥吸收效率均与杂交稻的生物量和产量极显著正相关。在施氮量为135 kg hm^-2 (N1)时，氮肥的农学利用率与生理利用率显著正相关，而在施氮量255 kg hm^-2 (N2)时，氮肥的农学利用率与氮肥的吸收效率、生理利用率显著正相关。

The Response of Indica Hybrid Rice Released at Different Periods to Nitrogen Application Level

Nitrogen is one of the most important macro elements; nitrogen use efficiency is affected by variety, nitrogen application level, application method and water management. In this paper, 16 three-line indica hybrid combinations released during 1976-2006 were widely planted in hybrid rice growing region with three nitrogen application levels in Fuyang, Zhejiang province. Yield and its components, indexes of rice N accumulation and translocation, and N use efficiency were analyzed. The results were as follows: (1) the former (released before 1985) and the middle (released between 1983 and 1993) combinations were more sensitive to nitrogen than the latter varieties (released after 1993), the yield of the former combination increased largely when 135 kg ha~(-1) nitrogen was applied, while the yield of the latter combination increased significantly till 255 kg ha~(-1) nitrogen was applied. (2) Nitrogen applica-tion increased the amount of N accumulation in plant. When nitrogen was applied at 135 kg ha~(-1), the increase of N content in stem, leaf and panicle is close to each other between combinations at different periods; when nitrogen was applied at 255 kg ha~(-1), N accu-mulation amount increased largely before flowering in the former combinations, while after flowering in the latter combinations. Nitrogen application did not affect the translocation rate in the former combinations, but dropped it largely in the latter combinations when nitrogen was applied from 135 kg ha~(-1) to 255 kg ha~(-1). (3) Nitrogen agronomic efficiency (NAE), partial factor productivity of applied N (PFP), nitrogen recovery efficiency (NRE) and physiological efficiency (NPE) decreased in the former combinations, when nitrogen was applied from 135 kg ha~(-1) to 255 kg ha~(-1), while NAE and PFP increased, NPE changed little in the latter combinations. (4) Correlation analysis showed AE, PFP positively corrected with plant nitrogen accumulation content, grain yield and biomass at P<0.01, only NPE positively correlated with NAE at P<0.05 at 135 kg ha~(-1) nitrogen application level, while both NPE and NRE positively correlated with NAE at P<0.05 at 255 kg ha~(-1) nitrogen application level.