在盆栽条件下 ,研究了添加双氰胺对尿素和碳酸氢铵在土壤中转化及芹菜对硝酸盐吸收的影响。在环境温度较高情况下 ,添加双氰胺对铵态氮转化为硝态氮的速率仍起到较大的抑制作用。施肥两周后土壤铵态氮含量基本恢复至施肥前的水平 ,碳铵添加硝化抑制剂的效果要好于尿素。芹菜植株硝酸盐含量分析结果表明 ,添加双氰胺处理的植株硝酸盐含量明显下降 ,产量未受显著影响。在本试验条件下 ,添加双氰胺的芹菜植株对肥料氮素利用率略有下降。 The effects of dicyandiamide on the conversion of urea and ammonium bicarbonate in soils and the nitrate uptake of celery were studied under potted conditions. At higher ambient temperatures, the addition of dicyandiamide still has a greater effect on the rate of conversion of ammonium nitrogen to nitrate nitrogen. After two weeks fertilization, the content of ammonium nitrogen in soil returned to the level before fertilization. The effect of adding ammonium nitrification inhibitor to ammonium bicarbonate was better than that of urea. The results of nitrate content analysis of celery showed that the content of nitrate in the dicyandiamide-treated plants decreased obviously and the yield was not significantly affected. Under the conditions of this experiment, celery plants with dicyandiamide added had slightly lower nitrogen use efficiency.