Testing nitrogen content in leaf is an important diagnostic means for N status of sugarcane. A pot experiment with different application rate of N fertilizer was carried out to evaluate the teasibility of SPAD as a diagnostic tool in sugarcane. Results showed that SPAD values, nitrogen content in leaf and cane yield increased steadily with application rate of nitrogen within a certain amount, then increased slowly or even declined after exceeding a certain level. Results also showed that the SPAD value had a significant positive relationship with nitrogen content in leaf and cane yield, which could be used as a nitrogen deficit indicator and be guidance for nitrogen application in sugarcane.%测定叶片氮素含量是甘蔗氮素营养诊断的一项重要方法。本研究利用桶栽试验,通过设置不同的供氮水平,研究了叶绿素仪用于甘蔗氮素营养快速诊断的适用性。结果表明:甘蔗叶片SPAD值、叶片氮含量及蔗茎产量在一定范围内随施氮量的增加而稳定增加;当施氮量超过一定水平后,随着施氮量的增加,甘蔗叶片的SPAD值、叶片氮含量和蔗茎产量的增幅趋缓,甚至下降;叶片SPAD值在不同甘蔗品种间具有差异。结果还表明:甘蔗叶片的SPAD值与叶片含氮量、蔗茎产量呈显著正相关,可在一定程度上预测甘蔗氮素丰缺,并用于指导甘蔗施氮。
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