广西稻区不同水稻品种对氮肥施用量的响应差异

Response difference of various rice varieties to nitrogen application rate in rice planting area in Guangxi

【目的】探明施氮量对不同水稻品种产量及其氮肥利用率的影响,为培育和利用氮高效水稻品种提供理论依据。【方法】选择适宜广西稻区的6个水稻品种,设4个施氮量水平(0、75、150和225 kg/ha)的田间试验,测定不同施氮量下各水稻品种的产量及其主要农艺性状和氮积累量,并计算氮肥利用率,通过回归分析各水稻品种产量与施氮量的关系,估算出获得最高产量时的施氮量及其氮肥农学效率和氮肥偏生产力。【结果】在0~225 kg/ha施氮量范围内,6个水稻品种的株高均随施氮量增加而增高,但有效穗数、穗长、穗粒数、结实率及千粒重与施氮量的关系表现不一致;水稻产量的总体变化趋势是随施氮量增加而增加,当施氮量达225 kg/ha时,除桂野丰产量开始下降外,其他品种产量增加缓慢。与无氮处理相比,施氮处理产量平均增产幅度在35.92%~67.45%,由高到低依次是恒丰优777>桂育11号>野香优3号>桂野丰>百香优139>桂育9号。6个水稻品种的氮肥吸收利用率、氮肥农学效率和氮肥偏生产力均随施氮量增加呈逐渐下降趋势;氮肥贡献率则随施氮量增加而增加,当施氮量达225 kg/ha时,氮肥贡献率增加缓慢甚至开始下降;不同水稻品种的氮肥利用率不同,氮高效利用品种(恒丰优777)的平均氮肥吸收利用率是氮低效利用品种(野香优3号)的1.53倍。6个水稻品种当季获得最高产量时的适宜施氮量在181.9~219.7 kg/ha,氮肥农学效率在10.1~17.9 kg/kg,氮肥偏生产力在30.6~41.9 kg/kg。【结论】不同水稻品种对氮肥的响应存在一定差异。本研究条件下,初步筛选出恒丰优777和桂育11号两个氮高效利用品种。

【Objective】Effects of nitrogen application rate on different rice varieties and nitrogen utilization efficiency were studied to provide theoretical basis for breeding and using high nitrogen efficiency rice varieties.【Method】Four nitrogen application rates(0,75,150 and 225 kg/ha)were applied on six rice varieties in Guangxi.Rice yield,main agronomic characters,nitrogen accumulation were tested to calculate nitrogen utilization efficiency under different nitrogen application rates.Correlation between rice yield and nitrogen application rate were determined by regressive analysis.The nitrogen rate for the maximum rice yield,nitrogen agronomic efficiency(NAE)and nitrogen partial factor productivity(NPFP)were estimated.【Result】In the range of 0-225 kg/ha nitrogen application rate,the plant height of the six rice varieties increased with the increase of nitrogen application rate,but the relationship between the effective panicle,ear length,grain number per ear,seed setting rate,1000-grain weight and nitrogen application rate showed inconsistent;the overall change trend of rice yield was to increase with the increase of nitrogen application rate.When the nitrogen application rate reached 225 kg/ha,the yield of the varieties increased slowly,except that Guiyefeng began to decline.Compared with the nitrogen-free block,the average yield increase was 35.92%-67.45%,the rank from high to low was Hengfengyou 777>Guiyu 11>Yexiangyou 3>Guiyefeng>Baixiangyou 139>Guiyu 9.The nitrogen uptake efficiency,NAE and NPFP of the six rice varieties showed a gradual decrease with the increase of nitrogen application rate;the contribution rate of nitrogen increased with the increase of nitrogen application rate,when the nitrogen application rate reached 225 kg/ha,the contribution rate of nitrogen increased slowly or even began to decline.Rice varieties showed different average nitrogen utilization efficiencies with 1.53 times difference between the high one(Hengfengyu 777)and the low one(Yexiangyou 3).The optimum nitrogen application rate for the six rice varieties to obtain the highest yields was 181.9-219.7 kg/ha,the NAE was 10.1-17.9 kg/kg,and NPFP was 30.6-41.9 kg/kg.【Conclusion】Rice varieties showed different nitrogen uptake efficiencies,Hengfengyou 777 and Guiyu 11 are screened as rice varieties with high nitrogen efficiency under this experiment condition.