In order to develop a method for rapid detection of total potassium content in leaf of maize, electrical impedance measuring method was used to collect the electrical impedance parameter of the leaf tissue juice under different potassium levels, and the relationship between impedance value and total potassium content of the leaf were investigated. Using stepwise regression method to choose the sensitive frequency for the total potassium content, every regression model included two sensitive frequencies based on which the linear regression equation was the best with the correlation coefficient of 0. 83 at least and root mean squared error of 0. 16 at most for four growth periods respectively. Therefore, it was demonstrated that impedance value could be a predictor for maize leaf potassium content. Electrical impedance measuring technology could be an available method for potassium fertilizer recommendation in crop.%研究了利用叶片组织汁液阻抗参数监测不同施钾处理下玉米各生育期的钾营养状况.结果表明,利用其总阻抗值可对植株的钾营养状况作定性分级判别.经过汁液总阻抗值和叶片钾质量分数的相关性分析,用逐步回归方法提取了钾质量分数差异敏感频段,并建立了基于叶片组织汁液总阻抗值的各生育期钾质量分数预测模型,各模型决定系数均大于0.83,均方根误差均小于0.16.电阻抗测量技术可以实现对作物钾营养状况的快速准确监测,为钾肥的实时定量施用提供决策支持.
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