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The improper or excessive use of herbicides has caused soil and water contamination, increasing the demand for techniques for environmental remediation. In this research, we assessed the effectiveness of nanostructured adsorbents in removing the herbicides mixtures of diuron, hexazinone, and sulfometuron-methyl, with the goal of applying this technique in environmental remediation efforts. The nanomaterials employed were microporous beta zeolite (BT), Al-MCM-41 mesoporous silica (AL), hydrotalcite clay (HT), and microporous carbonate biochar (BIO). The nanostructured adsorbents were characterized by X-ray diffraction, X-ray fluorescence, elemental analysis, and nitrogen adsorption and desorption at 77 K, point of zero charge, scanning electron microscope, and transmission electron microscopy. The descending adsorption values of nanostructured adsorbents: for diuron BT (99.35%) > BIO (96.36%) > AL (88.33%), hexazinone, BT (97.26%) > AL (83.75%) > BIO (14.22%), and sulfometuron-methyl, AL (95.73%) > BT (90.96%) > BIO (34.92%). The time required for the adsorption equilibrium was 1 hour, with greater adequacy to the pseudo-second-order kinetic model. The Langmuir and Freundlich isotherms showed the best fit of herbicide adsorption on the microporous BT and BIO, respectively. In the AL, the diuron and hexazinone experimental data fitted more precisely to Temkin's model and sulfometuron-methyl to Freundlich's model. Nanostructured adsorbents have different capacities to adsorb diuron, hexazinone, and sulfometuron-methyl herbicides present in aqueous media, with BT being the material with the highest adsorption capacity for the remediation of the mixture containing the three herbicides.

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.

Water stress is the main abiotic factor that limits the development and commercial quality of ornamental plants, such as Zinnia elegans. This study aimed to evaluate the ability of exogenous melatonin (MEL) to attenuate the deleterious effects of water deficit by modulating stomatal physiological, biochemical and structural parameters. Z. elegans plants were subjected to four water regimes (80% FC, 20% FC, early stress and late stress) with (1.0 mM) and without MEL application. Severe water stress (20% FC) drastically reduced the rate of CO2 assimilation (A) by 43.81% and stomatal conductance (gs) by 68.96%. However, the application of MEL significantly mitigated this damage, resulting in an increase in A of 26.99% gs of 43.75%, and relative water content of 28% in plants under severe stress compared with those in untreated stressed plants. The mechanism of action of MEL involves the modulation of stomatal motion and, as suggested, the promotion of osmotic fit and the protection of membrane integrity and photochemical efficiency. Exogenous melatonin acts as an effective bioregulator, improving the tolerance of Z. elegans to water deficit and sustaining its physiological performance and ornamental potential under stress conditions.

Postemergence application of herbicides can cause phytotoxicity problems in eucalyptus seedlings. Foliar fertilization can improve seedling development and mitigate the effects of herbicides on eucalyptus. Thus, the objective of this work was to evaluate the sensitivity of eucalyptus clones subjected to herbicides applied postemergence and associated with the application of foliar fertilizer. For this, a field experiment was carried out with the application of the products indaziflam, clomazone, glyphosate + S-metolachlor, sulfentrazone, and diuron + sulfentrazone, plus the application of an additional foliar fertilizer (composition in g/L of 78, 13, 40.3, 1.17, 0.78, 16.9, 13, 14.3, 0.52, and 29.9, respectively, for C, N, S, B, Co, Fe, Cu, Mn, Mo, and Zn). Height, stem diameter, shoot dry mass, chlorophyll content, and visual intoxication were the analyzed variables. The herbicides indaziflam and glyphosate + S-metolachlor were the most harmful to the tested eucalyptus clones, interfering with the growth variables. Among the evaluated clones, Clone AEC 144 had more significant changes in the analyzed variables in treatments with herbicides and foliar fertilizer application. The eucalyptus seedlings were generally more sensitive to indaziflam and glyphosate + S-metolachlor herbicides. Foliar fertilization reduced the intoxication caused by indaziflam in Clone AEC 056. The fertilizer intensified treatment symptoms with clomazone and diuron + sulfentrazone in Clone AEC 144 and with sulfentrazone and diuron + sulfentrazone in Clone AEC 2034.

Traditional methods of analyzing biofouling in emitters fail to capture the complexity and heterogeneity of their components. Therefore, the objective of this work was to develop and validate an innovative approach that integrates fractal metrics and scanning electron microscopy (SEM) to accurately characterize, quantify, and diagnose biofouling in drippers used with brackish water. For this purpose, tests were conducted on benches that applied brackish water and fresh water through drippers with a flow exponent (x) of 0.46 (NJ), 0.45 (SL), and 0.48 (ST) over 160 h. Biofouling was mapped using advanced diagnostics using SEM and factual metrics, and the results were analyzed using multivariate statistics. The results obtained present important findings for the study, detection, mapping, and proposal of mitigation measures for biofouling in drippers, presenting factual metrics that may be new indicators of clogging. Biofouling is a phenomenon resulting from the interaction between the spatial evolution of the obstructing material, emitter geometry, and irrigation water quality. The combination of SEM and fractal metrics has proven to be an advanced and innovative diagnostic tool for detecting the presence and distribution of biofouling, enabling clogging monitoring and creating more realistic scenarios in hydrodynamic studies to improve or develop emitter designs.

Pyrolysis conditions directly influence biochar properties and, consequently, influence the potential use of biochar. In this study, we evaluated the effects of different pyrolysis temperatures (450, 550, 650, 750, 850, and 950 °C) on the hydrogen potential, electrical conductivity, ash content, yield, volatile matter content, elemental analysis, Fourier-transform infrared spectroscopy results, X-ray diffraction results, scanning electron microscopy results, specific surface area, and micropore volume of eucalyptus wood-derived biochar. The degree of linear association between pyrolysis temperatures and biochar properties was examined using the Pearson correlation coefficient. The results showed a positive correlation of the pyrolysis temperature with the hydrogen potential value, electrical conductivity, and elemental carbon. There was a negative correlation of the pyrolysis temperature with the yield, volatile matter content, elemental oxygen, elemental hydrogen, surface area, aromaticity, hydrophilicity, and polarity indexes. The Fourier-transform infrared spectroscopy data indicated an increase in aromaticity and a decrease in the polarity of high-temperature biochar. The increased pyrolysis temperature caused the loss of cellulose and crystalline mineral components, as indicated by X-ray diffraction analysis and scanning electron microscopy images. These results indicated that changing the pyrolysis temperature enables the production of biochar from the same raw material with a wide range of physicochemical properties, which allows its use in various types of agricultural and environmental activities.

Abstract Herbicides play an important role in controlling weeds in agricultural crop areas. However, the lack of knowledge of their mobility in the soil may cause environmental damage, such as the contamination of soil and water bodies. Thus, this study was conducted to identify the effect of different rainfall intensities on the leaching potential of the herbicides diuron, hexazinone, and sulfometuron-methyl in red latosol. The trials were conducted in polyvinyl chloride columns. Rainfall simulations were performed for the following intensities: 10 mm h−1, 15 mm h−1, 20 mm h−1, and 25 mm h−1 of rainfall during 4 h. The columns were sectioned into seven layers (0–0.05; 0.05–0.10; 0.10–0.15; 0.15–0.20; 0.20–0.25; 0.25–0.30; 0.30–0.35 m), and the quantification of the herbicides in the layers was performed by Ultra-High Performance Liquid Chromatography coupled to the Mass Spectrometer. The diuron showed lower leaching potential in the soil, detected almost entirely in the upper layer of the column (0.0–0.05 m) for all precipitation applied. Hexazinone showed high leaching, being detected until the last layer of the soil (0.30–0.35 m) and in the water leached in the column when applied 20 and 25 mm h−1 of rainfall. Sulfometuron-methyl reached the last layer (0.30–0.35 m) when applied at an intensity of 25 mm h−1. Hexazinone showed higher leaching potential and consequent environmental risk. Diuron and sulfometuron-methyl were fewer mobiles in the soil profile; however, the environmental risk should be considered because higher rainfall intensities may alter their behavior in the soil.

Invasive grasses reduce resource availability, mainly nutrients in the soil, and the growth of eucalyptus plants. Efficient management to increase productivity depends on understanding levels of weed interference in eucalyptus plantations. The nutritional efficiency of eucalyptus plants in competition has been evaluated by plant tissue analysis. The objective was to evaluate the growth, relative accumulation of nutrients, and nutritional efficiency of the eucalyptus clonal hybrid I144 (Eucalyptus urophylla × Eucalyptus grandis), in competition with Megathyrsus maximus cv. BRS zuri, Urochloa brizantha cv. marandu, Urochloa decumbens cv. basilisk and in the control (eucalyptus plants without weed competition). The experiment was carried out with a completely randomized design, with four treatments and ten replications. The height, stem diameter, number of leaves, leaf area, dry matter of leaves and stem, nutrient content in leaves and uptake, transport, and N, P, and K utilization efficiency of the eucalyptus clonal hybrid were evaluated at 110 days after transplantation. The growth parameters and relative contents of macro and micronutrients in the eucalyptus clonal hybrid were lower in competition with M. maximus, U. brizantha and U. decumbens. The efficiency of N, P, and K uptake and transport by the eucalyptus clonal hybrid was 29.41 and 7.32% lower in competition with U. decumbens than in the control treatments, respectively. The efficiency of N, P, and K utilization by eucalypts was 13.73, 9.18, and 22.54% lower in competition with M. maximus, U. brizantha, and U. decumbens, respectively. The reduced growth and nutritional parameters of the eucalyptus clonal hybrid were more evident in competition with U. decumbens. Plant tissue analyses efficiently determined the level of competition for nutrients between species. Crop competition with grasses can decrease the efficiency and use of nutrients, which consequently reduces plant development and productivity.

The occurrence of weeds in eucalyptus plantations can cause losses in productivity. Chemical control is widely used, but the efficiency of herbicides depends on management and environmental factors. This study aims to evaluate the efficiency of S-metolachlor + glyphosate in the control of grasses in different densities of eucalyptus straw and with simulated rainfall after application of the product. The experiment was conducted in a randomized block design, factorial, with four replications. The first factor represented 0; 1.06 + 0.79 e 2.12 + 1.59 kg i.a. ha−1 of the commercial dose of S-metolachlor + glyphosate, the second 0; 5 and 10 tons ha−1 of straw and, the third 25 and 50 mm of water depth applied in soil with a mix of grasses previously sowed. The evaluations carried out were fresh mass, dry mass, and visual analysis of the control percentage. The fresh and dry mass and the grasses’ dry mass/water ratio decreased with increasing herbicide dosage and straw density. The treatments without straw and with the herbicide application had the highest percentages of control, the highest in the dosage of 2.12 + 1.59 kg i.a. ha−1 of S-metolachlor + glyphosate. Applying different water depths (25 mm or 50 mm) did not influence the control. In conclusion, it was observed that the isolated straw promoted the control of grasses. However, in treatments that included straw and herbicide, there was a decrease in the efficiency of the product, which suggests an antagonism between the vegetation cover and S-metolachlor + glyphosate.

The leaching of herbicides into the soil is essential to control germinating seeds and parts of vegetative weeds. However, herbicide transportation to deeper soil layers can result in groundwater contamination and, consequently, environmental issues. In this research, our objective was to investigate differences in herbicide leaching between commercial formulations and analytical standards using three different soils. Leaching experiments were carried out for diuron, hexazinone, and sulfometuron-methyl herbicides isolated and in binary and ternary mixtures. The herbicide residue quantification was performed by ultra-high-performance liquid chromatography coupled to a mass spectrometer (LC-MS/MS). Diuron had less mobility in soils and was retained in the most superficial layers. Hexazinone and sulfometuron-methyl were more mobile and leached into deeper layers. The leaching process was more intense for hexazinone and sulfometuron-methyl. The additives present in the commercial formulation favored the leaching in soils of diuron, hexazinone, and sulfometuron-methyl herbicides isolated and mixture compared to the analytical standard. This fact highlights the importance of considering these effects for the positioning of herbicides in the field to increase the efficiency of weed control and minimize the potential for environmental contamination.