为了探索河套灌区春玉米氮肥适宜分次施用比例,依照测土配方施肥技术原理,在全生育期施N 171 kg/hm2条件下,研究了播种前(基施)、 拔节期、 大喇叭口期分次施氮比例对春玉米光合速率、 地上部干物质积累及产量的影响.结果表明,春玉米生育期内二次施氮可显著提高光合速率和产量;除基施外,最佳追肥时期为大喇叭口期.其中,氮肥基施和在大喇叭口期追肥比例为1:2时春玉米可获得最高产量(13.42 t/hm2),其光合速率最高值比同时期对照处理提高了34.11%,成熟期地上部干物质量比对照处理提高了31.47%,产量、 穗粒数、 千粒重也分别比对照处理提高了28.03%、15.84%、22.48%.综合考虑光合速率、 地上部干物质量及产量,推荐河套灌区春玉米合理氮肥运筹方式为:基施氮肥57 kg/hm2,大喇叭口期追施氮肥114 kg/hm2.%This study aimed to identify the optimal application method of nitrogen fertilizer for improving nitrogen use efficiency in cereal grain production. A field experiment was conducted to investigate the effects of nitrogen application period and ratio on photosynthetic rate and yield of spring maize in Wuyuan county, Inner Mongolia, China. In this experiment, N 171 kg/hm2 was applied to a certain proportion at planting, jointing and bell-mouthed periods of spring maize based on the soil test result. The results showed that the photosynthetic rate and yield of spring maize were significant higher in the twice fertilization treat-ments than those in the once and triple fertilization treatments. Except for basal fertilizer, the recommended dressing fertilizer time was at bell-mouthed period. Among the twice fertilization treatments, the highest yield of spring maize ( 13. 42 t/hm2 ) was obtained from the treatment in which the basal/topdressing ratio was 1:2. In this treatment, the highest photosynthetic rate was increased by 34. 11% than CK, the above-ground dry matter increased by 31. 47% at maturation period, the highest yield, seed number and 100-weight of spring maize increased by 28. 03%, 15. 84% and 22. 48% compared with those of CK, respectively. Based on photosynthetic rate, above-ground dry matter and yield, N 57 kg/hm2 applied at planting plus N 114 kg/hm2 applied at bell-mouthed period should be the optimal application method for spring maize production in the Hetao irriga-tion district.
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