The Dualex  a New Tool to Determine Nitrogen Sufficiency in Broccoli

Tremblay, N.; Belec, C; Jenni, Sylvie; Fortier, E.; Mellgren, R.

doi:10.17660/actahortic.2009.824.13

Cited by 20 publications

(15 citation statements)

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“…For estimating foliar N, the NBI index outperformed the Chl index as the incorporation of Flav concentration partially balanced the varying Chl/N ratio. This is in accordance with Cartelat et al () and Tremblay et al (), who reported a superior performance of the NBI compared to Chl or Flav indices. They related their findings to the opposing effect of N supply on the biosynthesis of Chl and phenolic substances, thereby increasing the relative difference between N concentration and to a compensation of pigment variations due to tissue inhomogeneity and leaf age.…”

Section: Discussionsupporting

confidence: 92%

Performance of reflectance indices and of a handheld device for estimating in‐field the nitrogen status of grapevine leaves

Friedel

Hendgen

Stoll

et al. 2020

Australian Journal of Grape and Wine Research

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Background and Aims Optical leaf sensing of plant nitrogen (N) status enables fertilisation based on plant demand. The aim of this study was to assess the suitability of leaf reflectance indices and of a handheld device for the estimation of N and chlorophyll (Chl) in Vitis vinifera L. cv. Riesling. Methods and Results Riesling leaves from a long‐term fertilisation trial were analysed for nitrogen and pigments and their spectral reflectance in the Vis/near‐infrared range was recorded for two consecutive seasons. In the second season the leaves were also measured with a Chl fluorescence based portable device (Dualex). Published reflectance indices and fluorescence indices were regressed against the concentration of pigment and N. Temporal changes in the Chl/N ratio complicated the indirect assessment of N via Chl. Red edge inflection points and several three‐ to four‐waveband indices allowed for a good prediction of leaf N. Fluorescence indices allowed for reliable estimation of N and Chl. Conclusions While leaf pigments can be analysed by simple two‐band indices, accurate N estimation requires more complex indices such as three‐band indices or indices calculated from derivative spectra. Significance of the Study Data from this study will assist growers to monitor non‐destructively the spatial and temporal variability of grapevine N status and thereby, improve fertilisation.

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Section: Discussionsupporting

confidence: 92%

Performance of reflectance indices and of a handheld device for estimating in‐field the nitrogen status of grapevine leaves

Friedel

Hendgen

Stoll

et al. 2020

Australian Journal of Grape and Wine Research

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“…the N-tester from Yara) are used as a decision support tool for N-fertilization of crops (Tremblay et al 2012). The combination of Chl and Flav in the Dx4 now allows a more widespread use of the NBI index that has been shown superior to Chl alone for N-fertilization in several crops (Tremblay et al 2009, Tremblay et al 2010, 2012). Calibration of Dx4 NBI for nitrogen management of grapevine and wheat is in progress in our laboratory.…”

Section: Resultsmentioning

confidence: 99%

A new optical leaf‐clip meter for simultaneous non‐destructive assessment of leaf chlorophyll and epidermal flavonoids

Cerović

Masdoumier

Ghozlen

et al. 2012

Physiologia Plantarum

432

319

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We have characterized a new commercial chlorophyll (Chl) and flavonoid (Flav) meter called Dualex 4 Scientific (Dx4). We compared this device to two other Chl meters, the SPAD-502 and the CCM-200. In addition, Dx4 was compared to the leaf-clip Dualex 3 that measures only epidermal Flav. Dx4 is factory-calibrated to provide a linear response to increasing leaf Chl content in units of µg cm–2, as opposed to both SPAD-502 and CCM-200 that have a non-linear response to leaf Chl content. Our comparative calibration by Chl extraction confirmed these responses. It seems that the linear response of Dx4 derives from the use of 710 nm as the sampling wavelength for transmittance. The major advantage of Dx4 is its simultaneous assessment of Chl and Flav on the same leaf spot. This allows the generation of the nitrogen balance index (NBI) used for crop surveys and nitrogen nutrition management. The Dx4 leaf clip, that incorporates a GPS receiver, can be useful for non-destructive estimation of leaf Chl and Flav contents for ecophysiological research and ground truthing of remote sensing of vegetation. In this work, we also propose a consensus equation for the transformation of SPAD units into leaf Chl content, for general use.

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“…The measurement of NO 3 concentration in plant tissue sap extracts has been documented for a long time (Prasad and Spiers, 1984) and found useful (Matthaüs and Gysi, 2001;Villeneuve et al, 2002;Tremblay et al, 2009b) for plants with a fleshy petiole. Yet, sap tests are not widespread, presumably due to the sampling, preservation, extraction, dilution, and measurement effort required.…”

Section: Nitrogen Nutrition Indexmentioning

confidence: 99%

Sensing of Crop Nitrogen Status: Opportunities, Tools, Limitations, and Supporting Information Requirements

Tremblay

Fallon

Ziadi

2011

hortte

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Diagnosing nitrogen (N) sufficiency in crops is used to help insure more effective management of N fertilizer application, and several indicators have been proposed to this end. The N nutrition index (NNI) offers a reliable measurement, but it is relatively difficult to determine. This index is based on the relationship between plant tissue N concentration and the biomass of the plant's aerial parts. However, a good estimate of the NNI should be obtained by nondestructive methods that can be carried out quickly. Although dependent on sites, chlorophyll meter (CM) measurements have been correlated with the NNI in corn (Zea mays). Since chlorophyll can be estimated through remote sensing, the possibility of quickly obtaining measurements for large surface areas points to practical applications for precision agriculture. When combined with the mapping of soil properties such as apparent electrical conductivity (EC), elevation and slope, such chlorophyll measurements make it possible to derive N fertilization recommendations by taking into account natural variations in the soil. Recently, an instrument called the Dualex (FORCE-A, Orsay, France) is marketed, which uses measurement methods based on the fluorescent properties of plant tissues. It is similar to the CM in terms of its operating principle but it measures polyphenolics (Phen), compounds that accumulate in the epidermis of leaves under N stress. Epidermal transmittance to ultraviolet light is assessed by the fluorescence excitation ratio F(ultraviolet)/F(REF), where F(ultraviolet) is the fluorescence excitation detected following ultraviolet excitation, and F(REF) is the fluorescence detected on excitation at a reference wavelength, not absorbed by the epidermis. Although the Dualex generally did not identify more differences among treatments than the CM in our studies on wheat (Triticum aestivum), corn, and broccoli (Brassica oleracea ssp. italica), combining the two measurements in a chlorophyll/Phen ratio improved the relationships with crop N nutrition status appreciably. This ratio can also be estimated by remote sensing techniques. The NNI on its own does not constitute an economically optimal recommendation for N fertilizer [economically optimal N rate (EONR)]. The EONR is the N rate at which profit is greatest. Work is currently being done to use overfertilized reference plots for this purpose and to permit an improved correlation between the indicator (NNI or chlorophyll) and EONR.

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The Dualex a New Tool to Determine Nitrogen Sufficiency in Broccoli

Cited by 20 publications

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Performance of reflectance indices and of a handheld device for estimating in‐field the nitrogen status of grapevine leaves

Performance of reflectance indices and of a handheld device for estimating in‐field the nitrogen status of grapevine leaves

A new optical leaf‐clip meter for simultaneous non‐destructive assessment of leaf chlorophyll and epidermal flavonoids

Sensing of Crop Nitrogen Status: Opportunities, Tools, Limitations, and Supporting Information Requirements

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The Dualex  a New Tool to Determine Nitrogen Sufficiency in Broccoli

Cited by 20 publications

References 0 publications

Performance of reflectance indices and of a handheld device for estimating in‐field the nitrogen status of grapevine leaves

Performance of reflectance indices and of a handheld device for estimating in‐field the nitrogen status of grapevine leaves

A new optical leaf‐clip meter for simultaneous non‐destructive assessment of leaf chlorophyll and epidermal flavonoids

Sensing of Crop Nitrogen Status: Opportunities, Tools, Limitations, and Supporting Information Requirements

Contact Info

Product

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The Dualex a New Tool to Determine Nitrogen Sufficiency in Broccoli