Received: January 24th, 2023 ; Accepted: May 22nd, 2023 ; Published: September 18th, 2023 ; Correspondence: [email protected] is an agricultural commodity with global commercial importance capable of
impacting the production chain. The quantification of defoliation at harvest is important for
monitoring crop yield because defoliation is one of the main types of damage caused by this
agricultural operation in coffee crops. Thus, the objective of this study was to evaluate the
relationship between yield and defoliation obtained in the field and obtained through remotely
piloted aircraft (RPA) images. The experiment was conducted in a coffee plantation belonging to
the Federal University of Lavras (UFLA), Lavras, Minas Gerais state, Brazil. An RPA with a
rotary wing containing a multispectral camera was used in autonomous flight mode with a height
of 30 m, an image overlap of 80%, and a speed of 3 m s-1
. The images were collected before and
after the 2020 and 2021 harvest, defoliation data obtained in the field were measured in 2020 and
2021, and the yield was measured from 2019 to 2021. Image processing was performed in the
software PhotoScan, postimage processing was performed in QGIS, and statistical analyses were
performed using the software R. With the processing of the images in 2020, the crop showed
reductions of 17.3% and 18.4% in leaf area and volume, respectively, after harvest. In 2021, the
crop showed reductions of 12.8% and 9.8% in leaf area and volume, respectively, after harvest.
The leaf area and leaf volume of the coffee plantation after harvest could be quantified by means
of images obtained by RPA, which allowed the observation of the loss of area and volume of the
coffee plantation. Furthermore, it was possible to analyse the interactions between field data and
the yield of the same harvest year, which were directly proportional, and the interaction of image
data from one year with the previous yield, which were inversely proportional. In the year 2020,
there was a reduction of 17.3% in leaf area after harvest, and a reduction of 18.4% in leaf volume
after harvest in the plots under study.In the processing carried out in 2021, there was a 12.8%
reduction in leaf area after harvest, and a 9.8% decrease in leaf volume after harvest in the plots
under study
