Fecha/hora: 16/06/2024 09:10:43

Biblioteca(s): 	INIA Las Brujas.	
Fecha corriente: 	06/03/2019	
Fecha de la última actualización: 	20/04/2020	
Autoria: 	PADILLA, F.M.; DE SOUZA, R.; PEÑA-FLEITAS, M.T.; GRASSO, R.; GALLARDO, M.; THOMPSON, R.B.	
Afiliación: 	FRANCISCO M. PADILLA, Department of Agronomy, University of Almeria, Spain; CIAIMBITAL Research Centre for Mediterranean Intensive Agrosystems and Agrifood Biotechnology, University of Almeria, Spain.; ROMINA DE SOUZA, Department of Agronomy, University of Almeria, Spain.; M. TERESA PEÑA-FLEITAS, Department of Agronomy, University of Almeria, Spain.; RAFAEL GILLSON GRASSO RODRIGUEZ, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay; MARISA GALLARDO, Department of Agronomy, University of Almeria, Spain; CIAIMBITAL Research Centre for Mediterranean Intensive Agrosystems and Agrifood Biotechnology, University of Almeria, Spain.; RODNEY B. THOMPSON, Department of Agronomy, University of Almeria, Spain; CIAIMBITAL Research Centre for Mediterranean Intensive Agrosystems and Agrifood Biotechnology, University of Almeria, Spain.	
Título: 	Influence of time of day on measurement with chlorophyll meters and canopy reflectance sensors of different crop N status.	
Año de publicación: 	2019	
Fuente/Imprenta: 	Precision Agriculture, 1 December 2019, Volume 20, Issue 6, Pages 1087-1106. OPEN ACCESS. Doi: https://doi.org/10.1007/s11119-019-09641-1	
ISSN: 	1385-2256	
DOI: 	10.1007/s11119-019-09641-1	
Idioma: 	Inglés	
Notas: 	Article history: Received 19 June 2019; Accepted 06 February 2020; Published 14 February 2020.
Corresponding author: Padilla, F.M.; Department of Agronomy, University of Almeria, Carretera de Sacramento s/n, La Cañada, Almería, Spain; email:f.padilla@ual.es	
Contenido: 	ABSTRACT.
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. 
© 2019, The Author(s).	
Palabras-Clave: 	IRRADIANCE; OPTICAL SENSORS; SOLAR RADIATION; SWEET PEPPER; VEGETABLE CROPS; VEGETATION INDICES.	
Categoría del tema: 	F01 Cultivo	
URL: 	http://www.ainfo.inia.uy/digital/bitstream/item/12498/1/10.1007-s11119-019-09641-1.pdf
https://link.springer.com/content/pdf/10.1007/s11119-019-09641-1.pdf	
Registro original: 	INIA Las Brujas (LB)	
Ejemplares: 	LB - (101796-1) - PXI - AP - DD - PP/PRECISION AGRICULTURE/2019 -  -  - DIS