Evaluación del dron como tecnología de aplicación de herbicidas

The use of drones in agriculture has increased exponentially in recent years, driven by advances in precision agriculture and by the operational advantages they offer over ground applications, especially under limited field access conditions. However, there is still limited information regarding their efficiency in pesticide applications and how operational variables affect spray deposition and weed control. This study aimed to evaluate the effectiveness of glufosinate ammonium applied with a DJI Agras T40 drone under different configurations of spray volume (8 L/ha and 16 L/ha) and droplet size (medium: 250µm and coarse: 500µm) in two vegetation conditions: a Dactylis glomerata pasture and Avena sativa crop. The experiments were conducted at INIA La Estanzuela Station (Colonia, Uruguay) using a randomized strip design, with continuous recording of climatic variables. Spray recovery was assessed using water-sensitive cards and Petri dishes, with the concentration of a fluorescent tracer (Tinopal) measured. In addition, deposition on plants was quantified through the measurement of the same tracer (Tinopal) using a spectrofluorymetry, and weed control efficiency was evaluated through visual assessment and NDVI analysis obtained by a multispectral drone. Results showed that the application volume was the most determining factor for both deposition and control, with significantly higher effectiveness at 16 L/ha compared to 8 L/ha. Droplet size also played a key role, with coarse droplets (500µm) resulting in greater recovery and deposition, associated with a lower proportion of driftable droplets and higher flight stability. Although spray volume did not significantly affect recovery, a positive trend was observed at higher volumes. In terms of deposition, a significant interaction between droplet size and volume was detected in D. glomerata, where the combination of higher volume and coarse droplets produced the highest Tinopal recovery. Regarding weed control, treatments with 16 L/ha achieved greater control levels, consistent with the differences observed in deposition and reflected in NDVI measurements. In summary, the spray volume was the most influential variable in the effectiveness of glufosinate applied by drone, while droplet size complemented its effect by improving product deposition on target. These results confirm the potential of drones as a viable tool for herbicide applications provided that operational parameters are properly selected, contributing to greater efficiency, reduced environmental impact and enhanced sustainability in agricultural practices.