###### Abstract  
The integration of precision agriculture technologies, such as remote sensing through drones and satellites, has significantly enhanced real-time crop monitoring. This study is among the first to combine multispectral data from both a drone equipped with Altum-PT camera and PlanetScope satellite imagery to predict fresh biomass in sweet basil grown in an open field, demonstrating the added value of integrating different spatial scales. A dataset of 40 sampling points was built by combining remote sensing data with field measurements, and seven vegetation indices were calculated for each point. Feature selection was performed using three different methods (F-score, Recursive Feature Elimination, and model-based selection), and the most informative features were then processed through Principal Component Analysis. Eight regression models were trained and evaluated using leave-one-out cross-validation. The best-performing models were Random Forest (R\({}^{2}\) = 0.96 in training, R\({}^{2}\) = 0.65 in testing) and k-Nearest Neighbours (R\({}^{2}\) = 0.74 in training, R\({}^{2}\) = 0.94 in testing), with kNN demonstrating superior generalization capability on unseen data. These findings highlight the potential of combining drone and satellite imagery for modelling basil agronomic traits, offering valuable insights for optimizing crop management strategies. machine learning; PlanetScope; unmanned aerial vehicles; remote sensing; random forest; k-nearest neighbour +
Footnote †: journal: Applied sciences  
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section and tends to become woody at the base. Leaves are petiolate with ovate-lanceolate lamina that are entire or sparsely serrated, and glabrous, measuring 2-5 cm in length. Its colour varies from pale green to intense green or purple in some varieties. Leaves are the main commercial part of interest of the plant. The flowers, small and white, have a corolla with five irregular petals and are grouped in infloresences at the axil of the leaves. The flowers are hermaphrodite, and the pollination is entomophilous; flowering takes place from June to October. The fruit is a tetrachenium from which four small oval dark brown achenes derive, detaching at maturity. Sweet basil is one of the most widely cultivated and distributed aromatic plants globally. In Italy, the cultivated area of basil reached approximately 290 hectares in 2024 [8]. This growth trend was driven by the rising demand from the food industry. Basil cultivation is particularly concentrated in four Italian regions: Lombardia, Emilia-Romagna, Marche, and Campania [9]. To improve basil production, precision agriculture integrated with innovative data analysis techniques is a promising solution. In recent years, the introduction of precision agriculture technologies has improved crop management, promoting greater economic, social, and environmental sustainability [10]. Remote sensing is a key technique in precision agriculture and allows for the precise monitoring of crop conditions. Among the most promising technologies, drones equipped with spectral sensors have proven to be effective tools for collecting detailed data on plant health and vegetation indices. An interesting point is that visible spectral sensors are suitable for the analysis and quantification of important plant properties such as phenolic compounds and flavonoids [11]. Another study focuses on the discrimination of basil from similar plants using chlorophyll fluorescence imaging techniques, with great results obtained [12]. Machine learning and deep learning techniques can be employed for the precise, real-time detection and classification of basil diseases, with the goal of improving agricultural productivity, reducing labour and costs, and increasing diagnostic accuracy [13]. For example, [PERSON] et al.