Impact of UAV-based herbicide application on growth and physiology of irrigated groundnut (Arachis hypogaea L.)

Abstract

A field experiment was conducted during the Rabi season of 2024-2025 at Deevanur village, Villupuram, Tamil Nadu, to evaluate the efficacy of drone-based Oxyfluorfen application on weed management and growth attributes in groundnut (Arachis hypogaea L.). The study included nine treatments comprising Oxyfluorfen applied at two doses (150 and 200 g ai/ha) with three spray volumes (40, 60, and 80 l/ha) using UAV, a manual application using Knapsack sprayer (500 l/ha), hand weeding, and a weedy check, arranged in a randomized block design with three replications. Significant differences were observed between the treatments for plant height, number of branches, SPAD, LAI, and dry matter production (DMP). The treatment T₁ (Oxyfluorfen @ 200 g ai/ha + 40 l/ha) consistently outperformed all others, recording the higher values of plant height (9.85, 25.85, 30.84 and 54.21 cm), number of branches per plant (10.11, 10.32 11.14 and 11.79), SPAD value (35.85, 42.50, 46.25 and 37.65); LAI (1.48, 2.16, 2.96 and 2.37) and DMP (550, 1872, 2751 and 4534 kg/ha) at 20, 40, 60 DAS, and at harvest, respectively. T1 was on par with T2 (Oxyfluorfen @ 200 g ai/ha + 60 l/ha) and T3 (Oxyfluorfen @ 200 g ai/ha + 80 l/ha) statistically. However, the weedy check (T₉) recorded the lowest values in all growth parameters, confirming the negative impact of weed competition on crop growth. UAV-based herbicide application at lower spray volumes with 200 g ai/ha (T₁) was more effective than higher volumes and manual methods, likely due to better canopy-level herbicide coverage and early weed suppression. These results indicate that UAV-based precision spraying of herbicides offers a promising and efficient alternative to traditional weed management practices in groundnut cultivation.