Analysis of Biophysical Variables in an Onion Crop (<i>Allium cepa</i> L.) with Nitrogen Fertilization by Sentinel-2 Observations
Alejandra Casella,
Luciano Orden,
Néstor A. Pezzola,
Carolina Bellaccomo,
Cristina I. Winschel,
Gabriel R. Caballero,
Jesús Delegido,
Luis Manuel Navas Gracia,
Jochem Verrelst
Affiliations
Alejandra Casella
Permanent Observatory of Agro-Ecosystems, Climate and Water Institute-National Agricultural Research Centre (ICyA-CNIA), National Institute of Agricultural Technology (INTA), Nicolás Repetto s/n, Hurlingham 1686, Buenos Aires, Argentina
Luciano Orden
Estación Experimental Agropecuaria INTA Ascasubi (EEA INTA Ascasubi), Ruta 3 Km 794, Hilario Ascasubi 8142, Buenos Aires, Argentina
Néstor A. Pezzola
Estación Experimental Agropecuaria INTA Ascasubi (EEA INTA Ascasubi), Ruta 3 Km 794, Hilario Ascasubi 8142, Buenos Aires, Argentina
Carolina Bellaccomo
Estación Experimental Agropecuaria INTA Ascasubi (EEA INTA Ascasubi), Ruta 3 Km 794, Hilario Ascasubi 8142, Buenos Aires, Argentina
Cristina I. Winschel
Estación Experimental Agropecuaria INTA Ascasubi (EEA INTA Ascasubi), Ruta 3 Km 794, Hilario Ascasubi 8142, Buenos Aires, Argentina
Gabriel R. Caballero
Departamento de Montevideo, Technological University of Uruguay, Av. Italia 6201, Montevideo 11500, Uruguay
Jesús Delegido
Image Processing Laboratory (IPL), Universitat de València, C/Catedrático José Beltrán, 2, 46980 Paterna, Spain
Luis Manuel Navas Gracia
Departamento de Ingeniería Agrícola y Forestal, Escuela Técnica Superior de Ingenierías Agrarias, Universidad de Valladolid, Avenida de Madrid 50, 34004 Palencia, Spain
Jochem Verrelst
Image Processing Laboratory (IPL), Universitat de València, C/Catedrático José Beltrán, 2, 46980 Paterna, Spain
The production of onions bulbs (Allium cepa L.) requires a high amount of nitrogen. According to the demand of sustainable agriculture, the information-development and communication technologies allow for improving the efficiency of nitrogen fertilization. In the south of the province of Buenos Aires, Argentina, between 8000 and 10,000 hectares per year−1 are cultivated in the districts of Villarino and Patagones. This work aimed to analyze the relationship of biophysical variables: leaf area index (LAI), canopy chlorophyll content (CCC), and canopy cover factor (fCOVER), with the nitrogen fertilization of an intermediate cycle onion crop and its effects on yield. A field trial study with different doses of granulated urea and granulated urea was carried out, where biophysical characteristics were evaluated in the field and in Sentinel-2 satellite observations. Field data correlated well with satellite data, with an R2 of 0.91, 0.96, and 0.85 for LAI, fCOVER, and CCC, respectively. The application of nitrogen in all its doses produced significantly higher yields than the control. The LAI and CCC variables had a positive correlation with yield in the months of November and December. A significant difference was observed between U250 (62 Mg ha−1) and the other treatments. The U500 dose led to a yield increase of 27% compared to U250, while the difference between U750 and U500 was 6%.