不同时期施氮对华南双季杂交稻产量及氮素吸收和氮肥利用率的影响

Effect of Nitrogen Application Timing on Grain Yield,Nitrogen Uptake and Use Efficiency of Hybrid Rice in South China

以两系法杂交水稻粤杂122为材料,在广州进行2 a 4季田间试验,研究了氮素作基肥、蘖肥和穗粒肥施用对水稻氮素吸收、稻谷产量和氮肥利用率的影响。结果表明:施用穗粒肥具有显著的增产作用,其增产效果比基肥和蘖肥好;施用穗粒肥显著提高水稻总吸氮量,基肥和蘖肥对吸氮量影响较小;在总施氮量相同的情况下,氮肥作穗粒肥施用的吸收利用率和农学利用率比基肥和蘖肥高;水稻最适吸氮量随结实期日照时数的增加而提高。控制氮肥总量,适当减少基肥和蘖肥用量,增加穗粒肥用量,实行氮肥后移,有利于提高华南双季杂交稻的产量和氮肥利用率。

Four field experiments were conducted in four cropping seasons of two years （2004-2005） at Guangzhou, Guangdong Province, China and the effects of nitrogen application timing on grain yield, nitrogen uptake, and the recovery efficiency （RE）, the agronomic efficiency （AE）, the internal use efficiency （IE）, the partial factor productivity （PFP） of fertilizer-nitrogen were investigated with Yueza 122, a two-line hybrid rice combination, as the material. The results showed that： a） Fertilizer-N applied at the early panicle differentiation （PD） and heading resulted in a grain yield increase in three out of four seasons, while N application as the basal or at tillering resulted in yield increase only in one of the four seasons, b） N application at PD and heading increased significantly the N uptake in all four seasons, while N application as the basal or at tillering did in only one season. For a given amount of fertilizer-N, RE and AE were greater when applied at PD and heading than as the basal or at tillering. c） The optimal N uptake increased with the number of sunshine hours during the grain-filling period. It is concluded that delaying the timing of fertilizer-N application by reducing N rate as the basal and/or at tillering and increasing N input at PD and heading are important to achieve a higher grain yield and N use efficiency for doublecropping hybrid rice in South China.