Unmanned Aerial Vehicles (UAVs) have become essential instruments for precision agriculture and forest monitoring, offering rapid, high-resolution data collection over wide areas. This review synthesizes global advances (2015–2024) in UAV-derived vegetation indices (VIs), combining bibliometric and content analyses of 472 peer-reviewed publications. The study identifies key research trends, dominant indices, and technical progress achieved through RGB, multispectral, hyperspectral, and thermal sensors. Results show an exponential growth of scientific output, led by China, the USA, and Europe, with NDVI, NDRE, and GNDVI remaining the most widely applied indices. New indices such as GSI, RBI, and MVI demonstrate enhanced sensitivity for stress and disease detection in both crops and forests. UAV-based monitoring has proven effective for yield prediction, water-stress evaluation, pest identification, and biomass estimation. Despite significant advances, challenges persist regarding illumination correction, soil background influence, and limited forestry applications. The paper concludes that UAV-derived vegetation indices—when integrated with machine learning and multi-sensor data—represent a transformative approach for the sustainable management of agricultural and forest ecosystems.

This study examined the effects of two apple cultivars (Gala and Jonagold), four irrigation levels (0, 10, 20, and 30 mm), and four fertilization treatments (N₀P₀K₀, N₈P₈K₈, N₁₆P₁₆K₁₆, N₂₄P₂₄K₂₄) on nursery tree density. Jonagold exhibited a slightly higher mean density (95.63 ± 4.790%) compared to Gala (93.50 ± 6.195%). Tree density peaked at 99.38 ± 1.295% under the 30 mm irrigation level and declined with reduced irrigation, while fertilization levels showed no significant independent effect. Both cultivars achieved their highest densities under the 30 mm irrigation level (Gala: 99.25 ± 1.650%; Jonagold: 99.50 ± 0.827%), and several cultivar–fertilizer–irrigation combinations reached 100% density. The lowest density (89.00 ± 6.944%) occurred in Gala under the N₂₄P₂₄K₂₄ treatment without irrigation. Overall, results indicate that irrigation, particularly the 30 mm norm, is the key determinant of maximizing nursery tree density, with select combinations enabling complete survival.

This study addressed a significant and relevant issue, specifically the production of high-quality fruit planting material linked to an economically viable nursery operation. The process considered both the pedo-climatic conditions of the region where the fruit planting material was cultivated and the technological elements utilized. The objective of this research was to gather information regarding the necessity and effectiveness of implementing localized irrigation for plum trees in the nursery in the context of various fertilization treatments. It also aimed to investigate the variations in leaf area among Cacanska Lepotica and Stanley plum cultivars subjected to various irrigation (non-irrigated control, 10 mm, 20 mm, and 30 mm) and fertilization (unfertilized control, N₈P₈K₈, N₁₆P₁₆K₁₆, and N₂₄P₂₄K₂₄) methods. The study was conducted within a private nursery situated in the northwest region of Romania using a 4 × 2 × 4 split-split-plot design with five replications. This research took place in the summer of 2024, in the second field of the nursery during the growth stage of grafted trees. The implementation of various NPK fertilization methods (8%, 16%, and 24%) led to enhancements in leaf surface developments (increased by 6.53–16.14% compared to the control). The application of fertilization ranging from 8 to 16% and subsequently from 16 to 24% was effectively absorbed by the plum trees, resulting in a substantial growth of 180–226 cm². Irrigation with 30 mm generated significant increases in the leaf area of 4.42–14.27% compared to the control. To obtain optimal yields of grafted trees, it is advisable to utilize a combination of irrigation and NPK fertilization. To promote the appropriate growth and development of the trees, it is essential to monitor the soil moisture levels and to implement irrigation during times of water shortage when the trees exhibit heightened water usage. The research findings indicated that both cultivars experienced similar advantages from 24% NPK fertilization and 30 mm of irrigation; therefore, the implementation of the aforementioned technological elements is strongly recommended.

This study aims to evaluate the impact of irrigation and fertilisation practices on the productivity of apple trees cultivated in nursery settings. Tree growth and yield in such environments are largely determined by the effective management of water resources and nutrients supplied through fertilisers. Given the growing importance of resource sustainability, diverse management approaches are being employed to optimise the use of water and fertilisers while maintaining desirable yield levels. The study was conducted at a privately operated nursery located in northwestern Romania. A three-factor experimental design (4 × 2 × 4) was employed, comprising five replicates per treatment. Each experimental plot contained four apple trees, planted at a distance of 0.7 x 0.25 m. The main factor was irrigation, the secondary factor was cultivar, and the tertiary factor was fertilisation. MM 106 apple layering, classified within the "Certified" category, served as the main biological material for this research. Grafting material consisted of dormant buds from the Gala and Jonagold cultivars, obtained from a virus-free mother-branch plantation located within the same nursery. Four irrigation treatments were applied: no irrigation, irrigation with 10 mm, 20 mm and 30 mm. Additionally, four NPK fertilisation regimes were tested: (N0 P0 K0 , N8 P8 K8 , N16 P16 K16, N24 P24 K24 ). The application of different doses of NPK resulted in a significant increase in tree production, of 145-187.4%, compared to the non-fertilised variant. Irrigation had a significant effect on the production of grafted trees, with increases of 110.64-158.62%. Fertilisation made the highest contribution to the variability of grafted tree production for the two apple cultivars (57.78%), significantly higher than the effect of irrigation (15.26%) and cultivar (0.75%). Similarly, simple (9.09-11.01%) and double (2.99%) interactions between factors also had significant influences on the production of grafted trees for the apple species.

The production of pear (Pyrus communis L.) nurseries is essential to providing high-quality planting material for the establishment of a successful orchard. Thus, encouraging early vegetative growth and seedling vigor during the nursery period requires optimal fertilization. Under temperate continental circumstances in northwest Romania, this study assessed the impact of various NPK fertilizer rates on the shoot fresh weight of pear nursery trees. The study was carried out in 2025 using a factorial design with two Romanian cultivars (‘Napoca’ and ‘Monica’) and four fertilization treatments (N₀P₀K₀, N₈P₈K₈, N₁₆P₁₆K₁₆, and N₂₄P₂₄K₂₄), set up in a randomized block system with five replications. At progressively higher rates of 50, 100, and 150 kg ha⁻¹, a totally water-soluble 16–16–16 fertilizer was applied. At the conclusion of the growing season, the fresh weight of the shoots was measured. The accumulation of shoot biomass was significantly and gradually impacted by fertilization. The fresh weight of the shoots rose by 29%, 45%, and 59% as compared to the unfertilized control (0.42 kg tree⁻¹) under the treatments of N₈P₈K₈, N₁₆P₁₆K₁₆, and N₂₄P₂₄K₂₄. There were no discernible cultivar-dependent variations at any fertilization level, and both cultivars showed almost equal growth responses. These findings show how strongly the growth of pear nursery shoots depends on the availability of NPK and offer helpful advice for maximizing fertilization techniques to enhance the quality of planting materials.

This study examined the effects of two apple cultivars (Gala and Jonagold), four irrigation levels (0, 10, 20, and 30 mm), and four fertilization treatments (N0P0K0, N8P8K8, N16P16K16, N24P24K24) on nursery tree density. Jonagold exhibited a slightly higher mean density (95.63% ± 4.790) compared to Gala (93.50% ± 6.195). Tree density peaked at 99.38% ± 1.295 under the 30 mm watering norm and declined with reduced irrigation, while fertilization levels showed no significant independent effect. Both cultivars achieved their highest densities under the 30 mm watering norm (Gala: 99.25% ± 1.650; Jonagold: 99.50% ± 0.827), and several cultivar–fertilizer–irrigation combinations reached 100% density. The lowest density (89.00% ± 6.944) occurred in Gala under the N24P24K24 treatment without irrigation. Overall, results indicate that irrigation, particularly the 30 mm norm, is the key determinant of maximizing nursery tree density, with select combinations enabling complete survival.