Land use/land cover change detection and crop monitoringof citrus orchards with SAR images in Antalya-Aksu

Antalya province has an important role in terms of agricultural production in our country due to its favorable climatic conditions and fertile lands. Citrus fruits are the most widely grown fruit species, take first place in the world and also has a remarkable importance for trade in Turkey. In this study, it is aimed to monitor citrus trees, which have a widespread production in Antalya by using Synthetic Aperture Radar (SAR) data with considering the age groups. Second stage of the study is to research the possibilities of the land cover and land use classification for a wider region which also includes citrus orchards, with SAR data. In order to achieve crop monitoring part, the images of 2018 and 2015 of the Sentinel-1 satellite, which was first launched by the European Space Agency, were downloaded for each month and multi-stage pre-processing studies were carried out on these SAR images of citrus orchards of govermental lands with known ground truth. The average scattering of citrus parcels in different age groups were recorded for each month of the years 2015 and 2018. According to the statistical analysis of the scattering values obtained over 12 months for 2015 and 2018, middle-aged citrus trees were more distinct than other age groups. Considering the physiological development periods of citrus trees, which are stagnant, flowering, fruit set and fruit maturity periods, it was found that all trees showed high scattering during the flowering period in both VH and VV polarizations for 2015 and 2018, and low scattering during the fruit set period. The other stage of the study, land cover and land use classification with SAR data, fusion of Sentinel-1 SAR images with Sentinel-2 optical satellite images was found to be appropriate, and the object-oriented approach as the classification method yielded successful results. According to the results of object-based classification made with the image obtained by the fusion of optical-EVI-SAR images, an increase of 11% in forested areas and a decrease of 22% in permanent crops were determined from 2015 to 2018. In addition, while greenhouse areas increased by 15%, a decrease of 2% in open areas with little or no vegetation, an increase of 25% in annual crops, a decrease of 7% in urban texture and an increase of 7% in inland waters were determined.