Evaluation Spectral Properties of Sunflower Throughout the Growing Season

Agriculture is one of the sector that widely use remote sensing (rs) techniques. crops can be monitored effectively throughout their growing seasons using rs techniques. especially, satellite images enable accurate monitoring of numerous properties of crops in big scale agricultural land, depending on the satellite frequency and image resolution. however, since implementation of this type of monitoring and assessment process in application, it is necessary to know relationships between crop properties and remotely sensed data. therefore, research studies including measurements of spectral data in the field are very important. in this study, spectral reflectance properties of sunflower were measured using a spectroradiometer throughout the growing season. this study was conducted in some sunflower fields of yeşilören, çayırözü ve uzunyazı villages of amasya-merzifon county of turkey. the areas of those fields were varied between 0,19 and 5,0 ha. measurements were made for 80 different points and in 8 different days between may and september 2016. these spectral reflectance data were evaluated by using the normalized difference vegetation index (ndvi), soil adjustment vegetation index (savi) and simple ratio (sr) which are extensively referred in the literature. results indicated that spectral reflectance values, depends on the vegetation amount, growth level and spectral indexes were increased from may to july. however, after mid-july, spectral vegetation indexes tended to decrease due to flowering of sunflower. consequently, it is possible to conclude that sunflower crop can be monitored by using spectral reflectance data measured through field level spectroradiometer.