## 3 Results  
### Spectral and Temporal Behavior of Species  
Gaining knowledge on the spectral and temporal behavior of species in advance could lead to the design of a better procedure for classification. Figure 5 shows the simulated phenology of the dominant crop species of the Maccarese and Jolanda di Savoia farms (Table 1) derived from the Sentinel-2 normalized difference vegetation index (NDVI) time series data of 2023. As shown in Figure 5a, winter and durum wheat, barley, and triticale have high similarity in phenology patterns. Fava beans and peas start growing later than wheat and barley and are harvested at around the same time. Cardoon starts growing in autumn and has totally different phenology, thus it is expected to be discriminated easily from other species in early winter (Figure 5a). Maize, sorghum, rice, soybean, sunflower, and tomato species start to green-up from May but are harvested from September to October (Figure 5b). Peach, apple, and almond orchards start to green-up from January until October in this study's areas. Olive is an evergreen plant, and, even in winter, the NDVI is higher than 0.25. Simulation of alfalfa using the NDVI of Sentinel-2 was not successful, because alfalfa is cut 4-5 times between May and September, which makes the phenology pattern very different from other species. For this reason, instead of simulated phenology, the NDVI time series derived from Sentinel-2 is presented (Figure 5c). In Figure 6, the PRISMA-derived spectral signature of the species (acquired in 2023) is shown. The similarity between the species' spectra, calculated using the cosine similarity method (cosine similarity function of MATLAB), is shown as a heat map in Figure 6e. The spectral signatures of winter and durum wheat, and barley acquired on 1 April 2021 at the Maccarese farm show high similarity >95%) (Figure 6a), while the rest of the winter species (herbage and fava bean acquired on 1 April 2021 at the Maccarese farm and pea acquired on 24 April 2021 at the Jolanda di Savoia farm) show less similarity (Figure 6b). For summer crops (maize, sorghum, rice, soybean, sunflower, and tomato acquired on 3 July 2022 at the Jolanda di Savoia farm), there is less similarity between species' spectral signatures, except between sorghum and maize. Rice shows a lower value compared with other summer species in the short-wave infrared (SWIR), which could be related to the presence of water in rice fields (Figure 6c). For perennial crops (olive, almond, and alfalfa acquired on 17 May 2021 at the Maccarese farm and pear and apple acquired on 4 June 2021 at the Jolanda di Savoia farm), pear shows less absorption in the red (630-680 nm) and higher reflectance in the 1300-2400 nm spectral range with respect to other perennial species (Figure 6d). Figure 5: Plant simulated phenology derived from Sentinel-2 NDVI time series data of the (**a**) winter and durum wheat, barley, triticale, herbage, fava bean, and pea species; (**b**) maize, sorghum, rice, soybean, sunflower, and tomato species; (**c**) alfalfa, olive, almond, apple, pear, and cartoon species from the 2023 season. Figure 6: PRISMA-derived spectral signature of (**a**) winter and durum wheat, barley, and triticale acquired on 1 April 2021 at Maccarese farm; (**b**) herbage and fava bean acquired on 1 April 2021 at Maccarese farm and pea acquired on 24 April 2021 at Jolanda di Savoia farm; (**c**) maize, sorghum, rice, soybean, sunflower, and tomato species acquired on 3 June 2022 at Jolanda di Savoia farm; (**d**) olive, almond, and alfalfa acquired on 17 May 2021 at Maccarese farm and pear and apple acquired on 4 June 2021 at Jolanda di Savoia farm; and (**e**) similarity between the spectra of different species’ PRISMA image from the four selected test sites. Figure 7a shows the spectra of a specific pixel of the wheat fields from April and May's PRISMA images. In April, the wheat is in the heading stage and has strong chlorophyll absorption and high reflectance in the 800-1200 nm spectral range.