In a groundbreaking field experiment conducted in India, drone sprayers have demonstrated their potential to revolutionize weed management in soybean cultivation. The study, titled ‘Comparative Evaluation of Knapsack, Boom, and Drone Sprayers for Weed Management in Soybean (Glycine max L.),’ was carried out during the Kharif season of 2021-22 at an experimental farm affiliated with the Department of Agronomy, Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani. The findings reveal that drone sprayers can save up to 85% in herbicide application time, water, and labor, marking a significant leap forward in agricultural technology.
The primary objective of the study was to evaluate the comparative efficacy of various sprayers in controlling weeds in soybeans and their work efficiency. The Randomized Block Design (RBD) included ten treatments of pre-emergence (PE) and post-emergence (POE) herbicides applied by knapsack, boom, and drone sprayers. The research team employed a Quadcoptor type drone sprayer with a 10-litre tank capacity, while the boom sprayer was a solar-operated bullock-drawn model. Pendimethalin 30% EC was used for pre-emergence herbicide application, and Imazamox 35% EC combined with Imazethapyr 35% WG was used for post-emergence.
The experiment unveiled remarkable outcomes in weed management within soybean cultivation. The drone sprayer exhibited exceptional work efficiency, reducing the time required for herbicide application by up to 99% compared to traditional methods. Specifically, the drone required only 20 minutes per hectare, with a high flow rate of 3.5 litres per minute and a speed of 4.5 meters per second. In stark contrast, the knapsack sprayer took 8 hours per hectare due to its lower flow rate of 0.9 litres per minute. The boom sprayer required 2 hours per hectare, using 5.5 litres per minute. Hand-weeding was the most time-consuming method, taking a total of 60 hours per hectare for three passes.
The drone sprayer also demonstrated substantial reductions in water usage, requiring only 25 litres per hectare. This efficiency is attributed to the precise droplet size produced by the drone, which enhances the herbicide’s effectiveness. In comparison, the knapsack sprayer required 625 litres per hectare for pre-emergence spraying and 520 litres per hectare for post-emergence. The boom sprayer needed even more water, with 660 litres per hectare for pre-emergence and 560 litres per hectare for post-emergence spraying.
Importantly, drone-based herbicide spraying showed the potential for a 30% reduction in herbicide dose application, highlighting its viability for minimizing herbicide usage. This positions the drone sprayer as a valuable tool for weed detection and herbicide resistance reduction. While the knapsack sprayer exhibited the highest weed control efficiency, statistically equivalent to the drone sprayer for both PE and POE treatments, the drone sprayer still outperformed in terms of labor and resource efficiency.
The study also assessed various parameters to evaluate the effectiveness of weed control strategies. Weed count per square meter and dry weight of weeds at different growth stages were examined. The weed-free condition achieved via hand-weeding exhibited the lowest weed count and dry weight, followed closely by treatments involving PE and POE herbicides applied through drone and knapsack sprayers. This parity underscores the efficacy of these treatments in reducing weed populations and dry weight.
Further evaluation of weed control efficiency (WCE) at different growth stages revealed that the application of PE and POE herbicides using knapsack, drone, and boom sprayers significantly influenced WCE. The weed-free treatment exhibited a high WCE, comparable to the knapsack sprayer application. However, the drone and boom sprayer applications also demonstrated comparable efficiency to the knapsack sprayer.
The implications of these findings are profound. Optimizing spraying techniques, particularly through the use of drones, can enhance soybean cultivation efficiency while aligning with sustainable development goals. This approach mitigates the environmental impacts associated with herbicide usage, marking a significant step forward in sustainable agriculture.