Insecticide applications are typically being carried out with traditional manual spraying equipment in redgram, which leads to inadequate control of insects due to higher crop height. The modern deployment of tractor-drawn spray machines causes serious damage to the crop. In this connection, unmanned aerial vehicle (UAV) spray technology has great potential for precise insecticide application in redgram crops. One of the important machine parameters influencing droplet deposition and drift characteristics in UAV sprayers is downwash airflow generated by a multi-rotor propeller. A field experiment was carried out at the redgram research field (N11.01, E76.92), Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, during 2021–2022 to study the spray drift and deposition characteristics of an autonomous UAV sprayer. The Imidacloprid (a.i. 17.8SL) insecticide mixed with water in a ratio of 1 mL per liter was sprayed with a UAV sprayer. Water-sensitive paper samples were kept at upper, middle, and bottom positions on the leaves, and data were analyzed for the spray droplet size, deposition rate, droplet density, and area coverage both in target and non-target areas using Spray Deposit Scanner software. UAV spray droplet deposition rate (2.93 ± 0.17, 2.01 ± 0.08, and 2.21 ± 0.162.38 μL cm⁻²), droplet density (47 ± 4.04, 53 ± 3.61, and 52 ± 8.74 droplets cm⁻²), and area coverage (15.72 ± 0.39, 16.60 ± 0.71, and 14.99 ± 0.39%) were highest in the upper layer as compared to the middle layer (droplet deposition rate: 1.21 ± 0.08, 1.07 ± 0.03, and 0.77 ± 0.02 μL cm⁻²; droplet density: 42 ± 2.52, 43 ± 8.50, and 38 ± 2.52 droplets cm⁻²; area coverage: 10.95 ± 0.81, 11.22 ± 0.56, and 8.57 ± 0.44%) and bottom layer (droplet deposition rate: 0.41 ± 0.06, 0.35 ± 0.03, and 0.33 ± 0.03 μL cm⁻²; droplet density: 22 ± 4.36, 17 ± 3.51, and 19 ± 4.51 droplets cm⁻²; area coverage: 2.78 ± 0.29, 2.95 ± 0.45, and 2.46 ± 0.20%, respectively). In the spray drift test, there was a higher droplet deposition rate (1.63 ± 0.09, 1.93 ± 0.05, and 1.82 ± 0.06 μL cm⁻²), area coverage (14.40 ± 0.07, 17.54 ± 0.36, and 16.42 ± 0.30%), and droplet density (46 ± 3.61, 54 ± 2.08, and 45 ± 3.21 No’s cm⁻²) in the target area as compared to the non-target area (droplet deposition rate: 0.88 ± 0.02, 0.46 ± 0.03, 0.22 ± 0.05, and 0.00 μL cm⁻²; droplet density: 23 ± 1.53, 11 ± 2.08, 6 ± 1.53, and 0.00 droplets cm⁻²; area coverage: 7.58 ± 0.34, 4.41 ± 0.19, 2.16 ± 0.05, and 0.00%, respectively), which may have been due to the downwash airflow produced by the multi-rotor propeller of the UAV sprayer. Finally, the UAV-based spraying technology results showed that the downwash air produced by the six-rotor propeller improved the penetrability of insecticide to crop leaves and led to a higher droplet deposition rate, droplet density, area coverage, and droplet penetrability on the upper layer, middle layer, and bottom layer of the plants.

Multi-rotor unmanned aerial vehicles (UAVs) have recently emerged as a leading technology for crop spraying, with significant attention from researchers and manufacturers focused on the performance of battery-powered hexacopter UAVs. The UAV-spraying is influenced by several factors including drone design, configuration, capabilities, operating parameters and crop type. Therefore, in this study, a six-rotor UAV sprayer was experimentally investigated to characterize spray droplets and its effectiveness in a groundnut research field. Chlorantraniliprole insecticide (18.5% SC) was applied at concentrations of 0.10%, 0.15%, 0.20%, and 0.25% using the UAV sprayer. The UAV sprayer was operated under optimized conditions, with a forward speed of 3.0 m s-1, a spray height of 1.0 m, and a pump discharge rate of 1.6 L min-1. An effective spray width of 2.5 m was found during the spraying experiments. Spray droplet samples were analyzed, revealing an actual spray deposition rate of 0.89 μL cm-2 in the upper layer and 0.72 μL cm-2 in the bottom layer of the canopy. Compared to a manual knapsack sprayer (upper layer: 1.34 μL cm-2; bottom layer: 0.32 μL cm-2), the UAV sprayer achieved more uniform coverage in both layers, with 7.43% and 6.32% spray coverage per unit area in the upper and bottom layers, respectively, compared to 9.49% and 3.18% for the manual method. The biological efficacy in controlling leaf folder insect on groundnut was 85.0% to 90.0%. The theoretical and actual application rates of the UAV sprayer were 49.0 L ha-1 and 47.0 L ha-1, respectively. The cost of operation for groundnut crop using a UAV sprayer has been estimated as 350 Rs ha-1 (770 Rs h-1 i.e., 9.2 USD h-1). The powerful downwash airflow generated by the UAV’s propellers enhanced uniform droplet deposition, spray coverage, and area coverage compared to the knapsack sprayer. These findings demonstrated the potential of multi-rotor UAVs for efficient insecticide application in small-scale groundnut farming, providing valuable insights for improving UAV-based crop spraying techniques.

Unmanned Aircraft Systems (UAS), also known as Unmanned Aerial Vehicles (UAVs) or drones, can fly autonomously. The application of drones is versatile in many applications such as spraying chemicals, spreading seeds, surveying farmlands, monitoring crops, and managing livestock. Their potential applications are seemingly endless. UAVs can be classified into numerous categories. As seen in Table 14.1, shows the category of UAVs. Figure 14.1 shows the classification of drones based on flying principle. <!----> <!----> <!----> <!---->

The present investigation aimed to gain insights into the structure of bioactive metabolic compounds in Nigella sativa L. seed oil. Initially, spectroscopic methods viz., GC-MS and FTIR were employed to determine functional groups, substituents, and conjugated double bonds in Nigella oil. GC-MS analysis identified 11 different amalgams, with p -cymene, ?-terpinene and ?-thujene being the major components. The FTIR spectrum revealed the presence of strong, sharp, and weak peaks, along with critical functional groups corresponding to C-H, O-H, C-C, C?N, and N-O, indicating the presence of pharmaceutically active constituents of the seed oil in the wavelength range of 400 – 4000 cm-1. HPLC analysis indicated that the percent composition of thymoquinone in the seed extract was reported as 0.90% at a wavelength of 254 nm. In the examined samples, thymoquinone and standard thymoquinone both showed a peak Rf value of 3.656. The study's findings revealed that thymoquinone is a potential phytochemical present in the oil. Furthermore, the identified biomolecules hold promise for use in pharmaceutical applications to enhance health standards.

The increasing demand for efficient and sustainable agricultural practices has necessitated the development of advanced mechanized solutions for orchard and field crop management. This study focuses on the design, structural analysis and development of Remote Operated Vehicle (ROV) and Remote Operated Sprayer (ROS) unit and evaluation of a Remote Operated Vehicle (ROV) for addressing the challenges of precision spraying in orchard crop applications. The ROOS features, an innovative wheel arrangement and suspension system, optimized for manoeuvrability and adaptability in diverse field conditions. The power required to operate the ROOS was 1.48 kW. Structural analysis performed using ANSYS software verified the frame’s reliability, with principal stress, von Mises stress, and deformation values well within safe limits. Performance evaluations revealed a minimum path deviation of 29 mm at a 25 kg payload and 3.5 km/h speed and a maximum deviation of 90 mm at a 150 kg payload and 5 km/h. Battery discharge and wheel slip were minimal under lower payloads and speeds, with values of 0.87% and 4.15%, respectively. The study highlights the ROOS potential as an efficient and adaptable mechanized sprayer for orchard crops. The outcomes underline the ROOS capability to contribute to sustainable agricultural practices by improving spraying efficiency and reducing resource wastage.