水稻甬优12产量13.5t hm~(–2)以上超高产群体的氮素积累、分配与利用特征

为探明甬优12超高产群体的氮素吸收与积累特征,2013—2014年,对高产(10.5~12.0 t hm–2)、更高产(12.0~13.5 t hm–2)、超高产(13.5 t hm–2)3个产量群体的氮素吸收与积累特征等进行了系统比较研究。结果表明,与高产和更高产群体相比:(1)超高产群体拔节期植株含氮率较低,抽穗期和成熟期植株含氮率高于对照。超高产群体拔节期氮素吸收量较低,抽穗和成熟期氮素吸收量较高。(2)超高产群体播种至拔节期氮素积累量和积累比例低于对照;拔节至抽穗期、抽穗至成熟期植株氮素积累量和积累比例高于对照。播种至拔节期氮素积累量与产量呈极显著线性负相关,拔节至抽穗期、抽穗至成熟期植株氮素积累量与产量呈极显著线性正相关。(3)超高产群体抽穗期和成熟期茎鞘、叶片和穗部氮素吸收量较高,且花后茎鞘氮素转运量和穗部氮素积累量也较高。花后茎鞘氮素转运量与实产呈显著线性正相关;穗部氮素积累量与实产呈极显著线性正相关。(4)甬优12超高产群体氮素吸收利用参数为,籽粒生产率50.8 kg grain kg~(–1)、百千克籽粒吸氮量1.97 kg、氮肥偏生产力42.1 kg kg–1、氮收获指数0.552。本研究表明,与一般高产群体相比,甬优12超高产群体氮素吸收具有拔节前较低、拔节至抽穗期和抽穗至成熟期高的特点;促进花后茎鞘氮素转运量有利于提高水稻产量。甬优12超高产群体百千克籽粒吸氮量2.0 kg左右,其氮素利用效率较低,在其超高产栽培管理中应重视氮素的高效利用。

Accumulation,Translocation and Utilization Characteristics of Nitrogen in Yongyou 12 Yielding over 13.5 t ha-1

In order to determine the absorption and accumulation of nitrogen (N) in super high yielding rice population of Yongyou 12, the field experiments were conducted with these populations of high yield (HY, 10.5–12.0 t ha^-1), higher yield (HRY, 12.0–13.5 t ha^-1), and super high yield (SHY, >13.5 t ha^-1) in 2013 and 2014. Results indicated thatcompared with HRY and HY. SHY showed lower N content at jointing while higher N content at heading and maturity. SHY showed lower N accumulation at jointing while higher N accumulation at heading and maturity. N accumulation and accumulation rate from sowing to jointing of SHY was lower, while opposite trends were observed from jointing to heading and from heading to maturity for SHY. There existed a very significantly negative correlation between N accumulation from sowing to jointing and grain yield, while very significantly positive correlations were observed between N accumulation from sowing to jointing and from heading to maturity and grain yield. SHY showed higher N accumulation in leaf, stem, and panicle at heading and maturity, as well as N translocation from stem and N increase in panicle after heading. There existed a significantly positive correlation between N translocation from stem after heading and grain yield, while a very significantly positive correlation was observed between N increase in panicle after heading and grain yield. When values were averaged across two years,internal nutrient efficiency, N uptake in the panicle per hundred, partial factor productivity, and N harvest index of SHY were 50.8kg grain kg^-1, 1.97kg, 42.1kg kg^-1, and 0.552, respectively. Our study indicated that SHY showed lower N accumulation before jointing, while higher N accumulation from jointing to heading, and from heading to maturity, when compared with check. Increasing N translocation from stem after heading was beneficial to improve grain yield. N uptake in the panicle per hundred of SHY was 2.0kg, relatively low P use efficiency was observed in SHY, a great attention should be paid to improving P use efficiency.