氮肥运筹模式对双季稻北缘水稻氮素吸收利用及产量的影响

Nitrogen uptake,utilization and rice yield in the north rimland of double-cropping rice region as affected by different nitrogen management strategies

在双季稻北缘地区,以常规品种早籼65和杂交组合香两优68为试验材料,在施氮量150 kg/hm2的条件下,研究了不同氮肥运筹模式对早稻产量及氮素吸收利用特性的影响。结果表明:减少基、蘖肥,提高穗肥比例可增加抽穗—成熟期的叶片含氮量,使SPAD值维持较高水平,提高齐穗后的绿叶面积和有效叶面积率,提高群体光合势,有利于促进干物质积累而提高产量和氮素吸收,常规稻和杂交稻均以基∶蘖∶穗=50∶25∶25运筹模式产量最高;前氮后移增施穗肥因能为水稻整个生育期提供比较平衡的氮素供应,可促进氮素的吸收;氮肥当季利用效率随穗肥比例提高而增加,但氮肥的农学利用率与产量有更好的对应关系。基∶蘖∶穗=50∶25∶25的运筹模式是双季稻北缘地区早稻合理的施肥技术。

Two early indica rice cultivars of Xiangliangyou 68 and Zaoxian 65 were used to study nitrogen uptake, utilization, yield and yield components as affected by different split N application strategies when the total nitrogen application amount was 150 kg/ha in the north rimland of double-cropping rice. Results showed that reducing N application before transplanting and at tillering stage but increasing N application at booting stage could increase rice yield and nitrogen uptake and utilization, by increasing leaf nitrogen content and SPAD in top 3 leaves during heading stage to mature stage, and increasing LAI and effective leaf area percentage. When nitrogen fertilizer was applied before transplanting （50 % ）, tillering （25 % ）, booting （25 % ）, both hybrid and conventional rice cultivars had highest yield. The main benefit of postponing N fertilizer application time on yield formation was related to its improved splitting and timing of fertilizer N applications leading to a more balanced supply of N nutrition for rice growth than the common fertilizer practice, and to increase total amount of N-absorption （ANA）. Nitrogen fertilizer use efficiency（NUE） increased with the percentage of panicle fertilizer, but the agronomic use efficiency of N fertilizer had better relationship with yield. It is concluded that the split application of N before transplanting （50%）, at tillering stage （25 % ） and at booting stage （25 % ） is a rational N application strategy in the north rimland of double-cropping rice.