Effect of cultivar on chlorophyll meter and canopy reflectance measurements in cucumber.

ABSTRACT.Optical sensors can be used to assess crop N status to assist with N fertilizer management. Differences between cultivars may affect optical sensor measurement. Cultivar effects on measurements made with the SPAD-502 (Soil Plant Analysis Development) meter and the MC-100 (Chlorophyll Concen...

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Bibliographic Details
Main Author: DE SOUZA, R. (author)
Other Authors: GRASSO, R. (author), PEÑA-FLEITAS, M.T. (author), GALLARDO, M. (author), THOMPSON, R.B. (author), PADILLA, F.M. (author)
Format: article
Language:English
Published: 2020
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Online Access:https://ainfo.inia.uy/consulta/busca?b=pc&id=60764&biblioteca=vazio&busca=60764&qFacets=60764
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Summary:ABSTRACT.Optical sensors can be used to assess crop N status to assist with N fertilizer management. Differences between cultivars may affect optical sensor measurement. Cultivar effects on measurements made with the SPAD-502 (Soil Plant Analysis Development) meter and the MC-100 (Chlorophyll Concentration Meter), and of several vegetation indices measured with the Crop Circle ACS470 canopy reflectance sensor, were assessed. A cucumber (Cucumis sativus L.) crop was grown in a greenhouse, with three cultivars. Each cultivar received three N treatments, of increasing N concentration, being deficient (N1), sufficient (N2) and excessive (N3). There were significant differences between cultivars in the measurements made with both chlorophyll meters, particularly when N supply was sufficient and excessive (N2 and N3 treatments, respectively). There were no consistent differences between cultivars in vegetation indices. Optical sensor measurements were strongly linearly related to leaf N content in each of the three cultivars. The lack of a consistent effect of cultivar on the relationship with leaf N content suggests that a unique equation to estimate leaf N content from vegetation indices can be applied to all three cultivars. Results of chlorophyll meter measurements suggest that care should be taken when using sufficiency values, determined for a particular cultivar. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.