Spatial variability of chlorophyll and NDVI obtained by different sensors in an experimental coffee field
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Kuupäev
2024
Kättesaadavus
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Estonian University of Life Sciences
Abstrakt
The objective of this research was to study the spatial variability of NDVI and
chlorophyll sampled by different sensors, as well as to evaluate the correlation between them in
a coffee field. The study was carried out on a coffee farm located in the municipality of TrĂªs
Pontas, Minas Gerais. A sampling grid containing 30 points was created for the study area. Each
sampling point was represented by one plant, which was georeferenced by a GNSS RTK. For
each sample plant, NDVI and chlorophyll were obtained by the optical and active sensors
GreenSeeker and ClorofiLOG, respectively. In addition, it was carried out a flight with an RPA
equipped with a passive and multispectral sensor. Using the data obtained by active sensors, a
geostatistical analysis was carried out to evaluate the spatial variability of NDVI and chlorophyll.
The geostatistical analysis verified the existence of spatial dependence for the two attributes, and
thus it was possible to generate spatialization maps through kriging. The images obtained by the
passive sensor resulted in five multispectral orthomosaics, making it possible to calculate the
NDVI, thus generating a spatialization map of this index. It was possible to observe in the
generated maps, points that presented a certain similarity and for this purpose a correlation
analysis was carried out for the values of each attribute, sampled directly in the maps, and in
different sampling grids (30, 60, 90 and 120 points). By analyzing the Pearson coefficient (R) it
was possible to quantify the level of correlation between the data obtained by the different sensors
and through the t test it was possible to find significant correlations between them.
Kirjeldus
Received: January 31st, 2024 ; Accepted: May 1st, 2024 ; Published: May 8th, 2024 ; Correspondence: gabriel.ferraz@ufla.br
Märksõnad
geostatistics, spatial distribution, spectral indices, active sensor, passive sensor, articles