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在田间和温室条件下分别用传统的硝化测氮法与叶绿素仪(SPAD meter)和Cardy NO3-nitrate meter两种便携式氮素测定仪对棉花花铃期氮素营养状况进行了评估和跟踪。结果表明,传统的硝化测氮法测得的叶片全N和叶柄NO3--N含量和叶绿素仪(SPAD meter)及Cardy NO3-nitrate meter的读数都反应出大田生长的棉株叶片和叶柄的含氮量因施氮水平、棉桃载荷和后期施用叶面氮肥而不同。在较高施氮水平下,单株棉桃数较少(即低载荷)以及叶面施用氮肥的棉株叶片和叶柄的含氮量明显高于其它处理,且叶绿素仪(SPAD meter)和Cardy NO3-nitrate meter的读数与叶片的全N百分数和叶柄NO3--N含量存在显著的正相关,其相关系数在大田条件下平均为0.70;温室条件下平均为0.90。
Nitrogen nutrition status of bolls was evaluated and tracked by using two portable nitrogen analyzers (SPAD meter and Cardy NO3-nitrate meter) under field and greenhouse conditions respectively. The results showed that the contents of total N, leaf NO3 - N, SPAD meter and Cardy NO3 - nitrate meter measured by the traditional nitrification and nitrogen assay all reflected the changes of leaf and petiole Nitrogen content varies due to nitrogen application, boll load and foliar application of nitrogen fertilizer. At higher nitrogen application levels, the nitrogen content of leaves and petioles of cotton plants with less bolls per plant (ie, low load) and foliar application of nitrogen fertilizer were significantly higher than those of other treatments, and the SPAD meter and Cardy NO3 There was a significant positive correlation between -nitrate meter and leaf N fraction and leaf petiole NO3 - N content, and the correlation coefficient was 0.70 in field and 0.90 in greenhouse.