Abstract: Nitrogen utilization and yield of ryegrass(Lolium muliiflorum) in salt stress under different nitrogen realms were studied using ¹⁵N labeling techniques.Results show that salt stress inhibited ryegrass dry matter and nitrogen accumulation.Nitrogen fertilizer can alleviate the symptoms of salt stress and improve ryegrass dry matter and nitrogen accumulation.Furthermore,ryegrass dry matter and nitrogen reach the maximum accumulation after top-dressing fertilization for 21 days.Nitrogen utilization of base fertilizer is higher than top-dressing fertilizer for cultivar Guicao No.1.The absorption of both fertilizer and soil nitrogen by ryegrass is increased with increasing nitrogen fertilizer.However,the utilization of nitrogen reduces when nitrogen fertilizer is more than 240 kg·hm^-2.These results indicate that nitrogen fertilizer 240 kg·hm^-2 may be optimum amount for production.

Key words: Nitrogen fertilizer rate, ¹⁵N, Dry matter, Nitrogen accumulation, Use efficiency

摘要： 采用¹⁵N示踪技术,研究了盐胁迫下不同施氮量对一年生黑麦草(Lolium muliiflorum)氮素吸收利用及产量的影响,以期探讨盐渍环境下氮素对其生长的影响,为进一步研究盐渍环境下黑麦草生产中氮肥的合理调控提供一定的理论依据。结果表明:盐胁迫抑制了黑麦草的干物质和氮素累积,增施氮肥可以缓解盐胁迫的症状,提高黑麦草的干物质和氮素累积。追肥21 d后,达到干物质和氮素的最大累积量。贵草1号对于底肥的利用大于追肥的利用。随着施氮量的增加,肥料氮和土壤氮的利用率增加,当施氮量超过240 kg·hm^-2时,氮素利用率降低。综合考虑产量、氮素利用率,一年生黑麦草施氮量为240 kg·hm^-2效果较好。

关键词: 施氮量, ¹⁵N, 黑麦草, 干物质, 氮素累积, 利用率