ANALYSIS OF IRRIGATED SUGARCANE FIELDS WITH BIOPHYSICAL PARAMETERS BY REMOTE SENSING IN THE BRAZILIAN NORTHEAST

Abstract

The cultivation of sugarcane occupies a significant area in the municipality of Juazeiro, BA, affecting the surrounding environment. The use of technologies, such as remote sensing and geoprocessing, has been helping to obtain important information about these agricultural areas. This work aimed to evaluate the spatial distribution of the components of the surface radiation balance in agricultural areas with the cultivation of irrigated sugarcane in the Brazilian semiarid region. This research was carried out in a portion of the Sub-Middle of São Francisco Valley, specifically in a commercial area cultivated with totally irrigated sugarcane, located in the municipality of Juazeiro, BA. The biophysical parameters (NDVI, surface temperature, surface albedo, and radiation balance) and the supervised classification Maximum Likelihood (Maxver) for the dates 09/03/2013, 09/22/2014, and 08/24/2015 were obtained through remote sensing from the digital processing of Landsat-8 satellite images, using the QGIS software. Through Maxver, it was possible to detect the different phenological stages (initial and maturation) of the sugarcane cultivations present in the region. Also, the results showed that the NDVI values are inversely proportional to temperature. The high albedo and low Rn values are related to bare soil and sugarcane straw. However, NDVI was high, Ts relatively low, and albedo and Rn relatively moderate in healthy vegetation. The spatial-temporal analysis of NDVI and Ts indicated variations in soil cover, highlighting distinct phases of development of the crop in the field. Finally, the methodology proved to be viable for mapping biophysical variables on different dates analyzed.