Unveiling the Ecological Ramifications of Aerial Pesticide Application by Drones on Soil Microbiota in Rice

Abstract

The ecological consequences of aerial pesticide application by drones on soil microbiota in rice fields were investigated in this study. The quantitative and qualitative effects of different pesticide treatments, both applied via drones and power sprayer, were examined on soil bacteria, actinomycetes, and fungi. The average population of total bacteria and pseudomonas in the rhizosphere soil tended to be slightly higher in the drone-sprayed treatments compared to the power sprayer treatments. It is evident that the drone spraying treatments resulted in higher average populations of actinomycetes and fungi (124.75 CFU × 105 g-1 soil and 21.12 CFU × 104 g-1 soil, respectively) compared to the power sprayer treatments with average populations of 127.75 CFU × 105 g-1 soil for actinomycetes and 22.5 CFU ×104 g-1 soil for fungi. Qualitative assessment of microbial groups revealed that, the abundance of G -ve bacterial groups are higher when compared to G +ve bacterial groups in rhizospheric soil before harvest of the crop. The distribution of fungal genera varied due to pesticide applications. The mean per cent occurrence of Curvularia spp., Penicillium spp., and Trichoderma spp. was slightly higher in the drone-sprayed treatments (9.85%, 8.51%, and 8.33%) compared to the power-sprayed treatments (2.48%, 2.24%, and 2.00%). However, the mean per cent occurrence of Aspergillus species (A. ochraceous, A. niger, and A. flavus) was relatively higher in the power sprayer treatments (9.14%, 12.81%, and 4.09%) when compared to the drone-sprayed treatments (3.75%, 2.31%, and 0.83%). Overall, this study underscores the need for further research to comprehensively understand the implications of different pesticide application methods on soil microbial communities and their potential impact on soil fertility and ecosystem functioning over time.