The Use of Diagnostic Optical Tools to Assess Nitrogen Status and to Guide Fertilization of Vegetables

Gianquinto, Giorgio; Orsini, Francesco; Sambo, Paolo; D’Urzo, Matilde Paino

doi:10.21273/horttech.21.3.287

Cited by 24 publications

(17 citation statements)

References 67 publications

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“…Additionally, tissue analysis i.e., total N analysis of leaves, has been used, but mostly for diagnosis of problems [ 19 , 20 ]. Although these procedures are useful, in particular the soil analysis based recommendation schemes for estimating total requirements, the analyses are time-consuming and do not yield results quickly in the field so as to make fertilizer recommendations on time [ 21 ]. This is particularly so for vegetable crops that receive frequent N application through fertigation, which is being increasingly used with intensive vegetable production throughout the world [ 18 , 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

Proximal Optical Sensors for Nitrogen Management of Vegetable Crops: A Review

Padilla

Gallardo

Peña-Fleitas

et al. 2018

Sensors

142

130

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Optimal nitrogen (N) management is essential for profitable vegetable crop production and to minimize N losses to the environment that are a consequence of an excessive N supply. Proximal optical sensors placed in contact with or close to the crop can provide a rapid assessment of a crop N status. Three types of proximal optical sensors (chlorophyll meters, canopy reflectance sensors, and fluorescence-based flavonols meters) for monitoring the crop N status of vegetable crops are reviewed, addressing practical caveats and sampling considerations and evaluating the practical use of these sensors for crop N management. Research over recent decades has shown strong relationships between optical sensor measurements, and different measures of crop N status and of yield of vegetable species. However, the availability of both: (a) Sufficiency values to assess crop N status and (b) algorithms to translate sensor measurements into N fertilizer recommendations are limited for vegetable crops. Optical sensors have potential for N management of vegetable crops. However, research should go beyond merely diagnosing crop N status. Research should now focus on the determination of practical fertilization recommendations. It is envisaged that the increasing environmental and societal pressure on sustainable crop N management will stimulate progress in this area.

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Section: Introductionmentioning

confidence: 99%

Proximal Optical Sensors for Nitrogen Management of Vegetable Crops: A Review

Padilla

Gallardo

Peña-Fleitas

et al. 2018

Sensors

142

130

View full text Add to dashboard Cite

show abstract

“…Given their ease of use, small size and relatively low cost, chlorophyll meters are very well-suited for on-farm use to provide rapid assessment of vegetable crop N status (Padilla et al 2018c). However, given the relatively small sampling area, appreciable repetition and strict sampling protocols have been developed for their practical use (Gianquinto et al 2011b;Padilla et al 2015;Samborski et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Influence of time of day on measurement with chlorophyll meters and canopy reflectance sensors of different crop N status

et al. 2019

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Optical sensors are a promising approach for assessing nitrogen (N) status of vegetable crops. However, their potential may be undermined if time of day influences measurements. This study evaluated the effects of time of day and N addition on measurements, made with two chlorophyll meters, SPAD-502 and MC-100, and two active canopy reflectance sensors, GreenSeeker handheld and Crop Circle ACS-470. Three treatments (N1, deficient, N2, conventional, and N3, excessive N application) of N concentration in the nutrient solution were applied by fertigation throughout a sweet pepper crop grown in soil in a greenhouse. Time of day of 12:00 and 15:00 h had an effect on measurements made with the SPAD-502, but only in the N1 treatment, suggesting that the effects of time of day were related to crop N status. This effect was slight, being 1.7 ± 0.02 SPAD units lower at 12:00 and 15:00 h compared to at 9:00 h (relative decrease of 3.6%). For the MC-100, a slight increase in Chlorophyll Content Index (CCI) values of 3.3 ± 0.1 units (relative increase of 6.3%) was observed at 15:00 and 18:00 h, relative to CCI values at 9:00 h, regardless of N treatment. The time of day effect on chlorophyll meters appears to be negligible in relation to the wide range of values measured in greenhouse-grown sweet pepper. Normalized Difference Vegetation Index, measured both with the GreenSeeker and Crop Circle, and Green Normalized Difference Vegetation Index, measured with the Crop Circle, were not affected by time of day in any of the N treatments, showing that these sensors and indices can be used with confidence at any time of the day.

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“…Digital cameras have also been used for near-ground remote sensing of crop growth and nutrient status [ 9 – 12 ]. Digital cameras measure red and green reflectance rather than red and infrared reflectance [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Use of a Digital Camera to Monitor the Growth and Nitrogen Status of Cotton

Jia

et al. 2014

The Scientific World Journal

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The main objective of this study was to develop a nondestructive method for monitoring cotton growth and N status using a digital camera. Digital images were taken of the cotton canopies between emergence and full bloom. The green and red values were extracted from the digital images and then used to calculate canopy cover. The values of canopy cover were closely correlated with the normalized difference vegetation index and the ratio vegetation index and were measured using a GreenSeeker handheld sensor. Models were calibrated to describe the relationship between canopy cover and three growth properties of the cotton crop (i.e., aboveground total N content, LAI, and aboveground biomass). There were close, exponential relationships between canopy cover and three growth properties. And the relationships for estimating cotton aboveground total N content were most precise, the coefficients of determination (R 2) value was 0.978, and the root mean square error (RMSE) value was 1.479 g m−2. Moreover, the models were validated in three fields of high-yield cotton. The result indicated that the best relationship between canopy cover and aboveground total N content had an R 2 value of 0.926 and an RMSE value of 1.631 g m−2. In conclusion, as a near-ground remote assessment tool, digital cameras have good potential for monitoring cotton growth and N status.

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The Use of Diagnostic Optical Tools to Assess Nitrogen Status and to Guide Fertilization of Vegetables

Cited by 24 publications

References 67 publications

Proximal Optical Sensors for Nitrogen Management of Vegetable Crops: A Review

Proximal Optical Sensors for Nitrogen Management of Vegetable Crops: A Review

Influence of time of day on measurement with chlorophyll meters and canopy reflectance sensors of different crop N status

Use of a Digital Camera to Monitor the Growth and Nitrogen Status of Cotton

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