Maria Carolina Ramirez Hernandez

Onion (Allium cepa L.) is highly sensitive to post-emergence herbicides, which limits chemical weed management, particularly under direct-seeding systems. In this context, organomineral fertilizers with biostimulant properties may represent a promising strategy to mitigate herbicide-induced phytotoxicity. This study evaluated the potential of an organomineral fertilizer to reduce phytotoxicity caused by post-emergence PPO-inhibiting herbicides in direct-seeded onion. A field experiment was conducted using a randomized complete block design with four replications. Treatments consisted of sequential applications of oxyfluorfen, flumioxazin, and oxyfluorfen + flumioxazin, combined with organomineral fertilizer application either as a tank mix or 3 days after herbicide application (DAA). Oxyfluorfen showed the highest crop selectivity, with phytotoxicity remaining below 15% throughout the experimental period, whereas the oxyfluorfen + flumioxazin combination caused the greatest injury, reaching 35% at 7 days after the first application. Treatments containing flumioxazin resulted in greater reductions in photosynthetic pigments and bulb yield. The organomineral fertilizer reduced phytotoxicity to as low as 5% in flumioxazin-treated plants and increased total bulb yield by 21.46% when applied as a tank mix and by 16.18% when applied at 3 DAA. These results indicate that organomineral fertilizer application can reduce visible injury and increase bulb yield under PPO-inhibiting herbicide treatments in direct-seeded onion.

Triazine herbicides are widely used for weed control in agricultural systems, and their occurrence in water bodies has been frequently reported worldwide. This study assessed the efficiency of a hydrochar derived from the epicarp and mesocarp of passion fruit residues for the removal of three triazine herbicides (atrazine, ametryn, and metribuzin), with the aim of developing a material suitable for application in water remediation programs. The adsorption capacity of biomass and hydrochar derived from passion fruit residues was evaluated with and without activation using 0.5 mol L⁻¹ phosphoric acid. The adsorption of herbicides was not significantly affected by pH within the range of 4 to 8. The acid hydrochar, which exhibited the highest removal capacity among the evaluated adsorbents, presented adsorption capacities of 18.05, 10.83, and 5.05 µg g⁻¹ for atrazine, ametryn, and metribuzin, respectively. These values correspond to removal efficiencies of approximately 62%, 72%, and 52% at initial concentrations of 0.33, 0.25, and 0.15 mg L⁻¹. The adsorption equilibrium time varied among the herbicides, reaching 4 h for atrazine and ametryn and 5 h for metribuzin. The adsorption dynamics between the adsorbents and adsorbates were best described by the pseudo-second-order kinetic model for ametryn and metribuzin, while atrazine had a higher correlation with the Elovich equation. The Weber–Morris model did not adequately describe the adsorption process. Among the isotherms tested, the Freundlich model provided the best fit for all three herbicides. The desorption rates of the acid hydrochar were 51%, 13%, and 83% for atrazine, ametryn, and metribuzin, respectively. Therefore, hydrochar derived from passion fruit residues represents a promising alternative for the remediation of triazine herbicides.

In recent years, wind power in Brazil has emerged as an alternative to diversify the country′s energy mix and minimize the emission of pollutants derived from fossil fuels. The state of Rio Grande do Norte, in the Brazilian Northeast, has considerable potential for the generation of wind energy due to the occurrence of strong winds in many areas along the coast and in the interior of the state, in places with higher altitudes. However, wind energy, despite being considered clean and renewable, can cause environmental impacts in those places. Thus, the present study analyzed the perception of environmental impacts caused by the installation of wind farms in the agricultural areas of Northeast Brazil. The study was carried out in the municipality of Serra do Mel, in the western region of the state of Rio Grande do Norte, based on a survey of local farmers. The study concluded that farmers live without major problems and without apparent conflicts with wind farms but have little knowledge about the environmental impacts. In the perception of most farmers, there are few negative environmental impacts, and those that exist are barely noticed or still do not cause damage to most farmers in the region.