An Analysis of Electrical Impedance Measurements Applied for Plant N Status Estimation in Lettuce (Lactuca sativa)

Sensors

Rafael F. Muñoz-Huerta²  Antonio de J. Ortiz-Melendez²  Ramon G. Guevara-Gonzalez²  Irineo Torres-Pacheco²  Gilberto Herrera-Ruiz²  Luis M. Contreras-Medina²  Juan Prado-Olivarez¹ 

[1] Departamento de Ingeniería Electrónica, Instituto Tecnológico de Celaya, Av. Tecnológico y García Cubas S/N, 38010 Celaya, Gto., Mexico; E-Mail:;Ingeniería de Biosistemas CA, División de Estudios de Posgrado, Facultad de Ingeniería, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, 76140 Querétaro, Qro., Mexico; E-Mails:

关键词: electrical impedance;    characteristic frequency;    plant N status;    Lactuca sativa;    plant nutrition;   

DOI  :  10.3390/s140711492

来源: mdpi

【 摘 要 】

Nitrogen plays a key role in crop yields. Hence, farmers may apply excessive N fertilizers to crop fields, inducing environmental pollution. Crop N monitoring methods have been developed to improve N fertilizer management, most of them based on leaf or canopy optical-property measurements. However, sensitivity to environmental interference remains an important drawback. Electrical impedance has been applied to determine the physiological and nutritional status of plant tissue, but no studies related to plant-N contents are reported. The objective of this article is to analyze how the electrical impedance response of plants is affected by their N status. Four sets of lettuce (Lactuca sativa L.) with a different N-source concentrations per set were used. Total nitrogen and electrical impedance spectra (in a 1 to 100 kHz frequency range) were measured five times per set, three times every other day. Minimum phase angles of impedance spectra were detected and analyzed, together with the frequency value in which they occurred, and their magnitude at that frequency. High and positive correlation was observed between plant N content and frequency values at minimum phase angle with no significant variations detected between days of measurement. These results suggest that electrical impedance can be sensitive to plant N status.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.