超级杂交早稻氮肥群体最高生产力及其增长特征

Population productivity and properties of early super hybrid cultivars under nitrogen fertilization

在大田条件下,以普通杂交早稻(荣优9号和五丰优623)为对照,设置5个氮肥水平(分别施N 0、135、165、195和225 kg/hm2),比较研究了超级杂交早稻(金优458、春光1号、03优66、淦鑫203)氮肥群体最高生产力及其群体特征。结果表明,1)除普通杂交早稻品种和个别超级稻品种(03优66)在165 kg/hm2水平外,其他超级早稻品种均在195 kg/hm2水平下产量达到最高(即表现氮肥群体最高生产力)。超级杂交早稻较普通杂交早稻产量平均增加8.42%,穗数增加10.67%,穗粒数增加13.96%,群体颖花量大是超级杂交早稻生产力提高的主要原因。2)在各品种的最高生产力条件下,与普通杂交早稻相比,超级杂交早稻各生育时期(有效分蘖临界叶龄期除外)的群体叶面积指数均显著提高,且抽穗后群体叶面积指数下降缓慢,群体光合势提高9.00%,从而显著增加了生育中后期的干物质积累量。3)超级杂交早稻氮素吸收总量达182.62(167.53～191.72)kg/hm2,较普通杂交早稻增加20.02%,其中拔节～抽穗期增加30.09%,抽穗～成熟期增加28.92%。与普通杂交早稻相比,超级杂交早稻的氮素农学利用率和生理利用率均明显提高,而氮素吸收利用率和氮素偏生产力却有所降低。

Based on the concept of the highest population productivity of rice under N fertilization, field experiments were carried out to investigate the highest productivity and its formation mechanism of the early-season super hybrid rice. Four early-season super hybrids （Jinyou 458, Chunguang 1,03 you 66 and Ganxin 203） and two ordinary hybrids （ Rongyou 9 and Wufengyou 623 ） which are widely grown by rice farmers in China were selected. There were five nitrogen levels, 0, 135, 165, 195 and 225 kg/ha. The main results show that the maximum outputs and the highest nitrogen population productivities of the early-season super hybrids are reached in the nitrogen level of 195 kg/ha, except that the early-season super hybrid, 03 you 66 and ordinary early-season hybridrice are in 165 kg/ha level. The yields of early-season super hybrids are increased by an average of 8.42% compared to that of the ordinary hybrid rice, and the number of effective panicles is increased by 10. 67% and the number of grains per spike is increased by 13.96%, which suggests that the higher total spikelet number is the main reason for the increase of productivity of the early-season super hybrids. Under their respective nitrogen levels of the highest population productivity, compared with the early-season ordinary hybrid, the leaf area indexes at growth stages of the early-season super hybrids are significantly improved except for at the stage of critical leaf age for effective tillers, and a slower decreasing process in leaf area index after the heading. The population photosynthetic potential is increased by 9.00%, which could increase dry matter accumulation in super hybrid rice, especially after the middle growth stage. Total nitrogen uptakes of super hybrids are from 167.53 to 191.72 kg/ha with an average of 182.62 kg/ha, and increased by 20. 02%, among which increased by 30. 09% from jointing to heading, and 28.92% from heading to maturity. The agronomic N use efficiency and physiological N use efficiency of the super hybrids are higher than those of the early-season ordinary hybrid, while the situation is quite the reverse for physiological N use efficiency and partial factor productivity of applied N.