Search Results (155)

Chickpea is a highly weed-prone crop with limited herbicide options and high labor demands, raising the following question: Can fall-planted legume–cereal cover crops (CCs) improve soil properties while reducing herbicide use and manual weeding pressure? To explore this, we evaluated the effect of fall-planted winter rye (WR) alone in 2021 and mixed with hairy vetch (HV) in 2022 and 2023 at Randolph farm in Petersburg, Virginia. The objectives were two-fold: (a) to examine the effect of CCs on soil properties using monthly growth dynamics and biomass harvested from fifteen 0.25 m²-quadrants and (b) to evaluate the efficiency of five termination methods: (1) green manure (GM); (2) GM plus pre-emergence herbicide (GMH); (3) burn (BOH); (4) crimp mulch (CRM); and (5) mow-mulch (MW) in suppressing weeds in chickpea fields. Weed distribution, particularly nutsedge, was patchy and dominant on the eastern side. Growth dynamics followed an exponential growth rate in fall 2022 (R² ≥ 0.994, p < 0.0002) and a three-parameter sigmoidal curve in 2023 (R² ≥ 0.972, p < 0.0047). Biomass averaged 55.8 and 96.9 t/ha for 2022 and 2023, respectively. GMH consistently outperformed GM in weed suppression, though GM was not significantly different from no-till systems by the season’s end. Kabuli-type chickpeas under GMH had significantly higher yields than desi types. Pooled data fitted well to a three-parametric logistic curve, predicting half-time to 50% weed coverage at 35 (MM), 38 (CRM), 40 (BOH), 46 (GM), and 53 (GMH) days. Relapses of CCs were consistent in no-till systems, especially BOH and MW. Although soil properties improved, CCs alone did not significantly suppress weed. Full article

Weeds pose a significant challenge to agricultural productivity, requiring control strategies that are both effective and environmentally sustainable. Therefore, this study evaluated the inhibitory potential of aqueous extracts from Ricinus communis L. leaves to manage the weeds Oryza sativa L. (weedy rice) and Cyperus ferax. Extracts were obtained through pressurized liquid extraction using water as the solvent. Bioassays were conducted during pre- and post-emergence stages by foliar spraying 15 and 30 days after sowing (DAS). The effect of extraction time (1–30 min) on inhibitory efficacy was also assessed. Chemical profiles of the extracts were characterized using high-performance liquid chromatography. The extracts significantly inhibited seed germination, with suppression rates reaching 92.7%. Plant growth was also diminished, particularly with earlier treatments (at 15 DAS), resulting in reductions of up to 32% and 53% in shoot length, and 69% and 73% in total dry mass for O. sativa L. and C. ferax, respectively. Mortality rates of O. sativa L. and C. ferax reached 64% and 58%, respectively. Phenolic compounds were identified in the extracts, and higher concentrations were observed at shorter extraction times. These findings underscore the potential of R. communis L. leaf extracts as an ecologically sustainable alternative for weed management, providing an effective and natural approach that may reduce reliance on synthetic herbicides and mitigate their environmental impact. Full article

A bioassay study was conducted to determine the differences in the sensitivity of selected crops to simulated clomazone residues (nine concentrations were used ranging from 5.625 to 1440 μg a.i./kg soil). White mustard was the most susceptible as measured by shoot fresh weight (SFW) and shoot dry weight (SDW) inhibition, with EC₅₀ values of 94.6 and 128.2 μg a.i./kg soil, respectively. Regarding the EC₅₀ values for the inhibition of pigment content (carotenoids, chlorophyll a and chlorophyll b), sugar beet and white mustard showed a high sensitivity, as the EC₅₀ values for all three pigments were in the range of 45.8–47.4 and 57.5–63.3 μg a.i./kg soil, respectively. However, as the SFW and SDW of sugar beet were only reduced at the three highest clomazone concentrations applied, white mustard proved to be the most sensitive crop. Wheat was less sensitive (EC₅₀ = 214.4–243.8 μg a.i./kg soil, for all three pigments), while sunflower and maize were the least sensitive (EC₅₀ = 359.7–417.5 and 456.1–535.8 μg a.i./kg soil, respectively). Field trials were conducted for two years in the Srem region to study the dynamics of clomazone degradation in sandy loam soil. Clomazone was applied pre-plant incorporated (PPI) and post-emergence (POST-EM) in three doses: 480, 720 and 960 g a.i./ha. Soil samples were taken at regular intervals from the day of herbicide application until one year after application and residue concentrations were determined using the white mustard bioassay (based on the measurement of carotenoid content inhibition). The application rate had no consistent effect on the persistence of clomazone. Slower degradation was observed in the PPI treatment than in the POST-EM treatment (8.5 and 15 days longer average half-lives in the first and second year, respectively). Persistence was affected by lower rainfall, resulting in a longer half-life in the second year (12 days on average). Herbicide residues caused no visible injury to white mustard one year after application, while the reduction in carotenoid content ranged from 0.37 to 22.89%, indicating that no injury can occur to any of the tested crops one year after application of clomazone in sandy loam soil. Full article

The use of preemergence herbicides is the primary method of controlling weeds in container-grown ornamental plants, but it may cause injury to common popular ornamentals. The objective of this research was to evaluate the use of overhead irrigation to reduce phytotoxicity in ornamental plants. Dimethenamid-P and flumioxazin were applied at standard label rates to container-grown coneflower (Echinacea purpurea), lady fern (Anthyrium filix-femina), and blue plumbago (Plumbago auriculata). Plants were subjected to one of four irrigation regimes at the time of herbicide treatment, including receiving 1.3 cm of overhead irrigation before treatment, immediately after treatment, both immediately before and after treatment, and no irrigation until the next irrigation cycle resumed at 4 h after treatment. For all three species, irrigation timing had minimal effect on visual injury ratings following treatment with dimethenamid-P, as injury was minimal overall. Severe injury was observed following treatment with flumioxazin, but significant recovery was noted in both lady ferns and echinacea when irrigation was applied immediately after treatment. The results indicate that irrigating plants immediately after treatment could improve crop tolerance to preemergence herbicide applications and should be further investigated as an injury management strategy for container-grown ornamental plants. Full article

The control of A. tauschii is critical to ensuring food security. This study investigated a range of different aspects of the biology of A. tauschii, including its emergence characteristics, population development dynamics, and its impact on wheat yield. Moreover, the efficacy of different herbicides and cultural control measures for managing A. tauschii was explored. Through laboratory cultivation and statistical analysis of the emergence rate of A. tauschii, it was found that its emergence rate significantly increased when temperatures ranged from 10 °C to 20 °C and the environmental osmotic potential fell between −0.1 MPa and −0.5 MPa—conditions similar to those found in wheat fields. Additionally, by recording the emergence rates at different depths, A. tauschii emergence was found to occur optimally at a sowing depth of 1–5 cm, which aligns with the shallow rotary tillage currently employed in wheat production. The weed was also found to be tolerant to weakly acidic and alkaline environments, while also presenting with moderate salt tolerance. Through field experiments, it was found that, upon spreading to new areas, A. tauschii rapidly expanded its population size. While its impact on wheat yield was relatively mild during the early stages of growth, it escalated to severe outbreaks with the passage of time. Field experiments were conducted to test the efficacy of five herbicides on weed control. The analysis indicated that Mesosulfuron-methyl was the only effective herbicide in controlling A. tauschii. Adopting three two-year-three-crop rotation patterns reduced the density of A. tauschii from 186 stems/m² to 11–15 stems/m². Watering-induced emergence also proved effective. The most effective watering was performed 15 days before sowing. Deep plowing was another effective measure. The deeper the plowing, the lower the emergence of A. tauschii. Delayed sowing time resulted in the additional suppression of the emergence of A. tauschii. Full article

Weeds are a significant challenge to global agricultural production, significantly impacting crop yields. The evolution of resistance to synthetic herbicides, along with their adverse environmental effects, underscores the need for alternative control strategies. This study reports the production, purification, and evaluation of the herbicidal activity of a metabolite produced by Phoma dimorpha (NRRL 43879) via submerged fermentation. To the best of our knowledge, this is the first report on the evaluation of the herbicidal potential of metabolites isolated from the cultivation of this microorganism. Metabolites extracted with ethyl acetate were fractionated into three fractions, with only one showing herbicidal activity. Fraction 1 controlled 96.25% of Amaranthus retroflexus plants in a leaf puncture bioassay at 2 mg mL⁻¹ and 96.67% when applied to the aerial parts at 600 µg mL⁻¹ with 0.1% Tween 80. The purified compound was also tested on Raphanus sativus seed germination, reducing rates by 80% and 26% at 24.5 mg mL⁻¹ and 12.25 mg mL⁻¹, respectively. Seedling length decreased by 80% and 31% under the same treatments. These results highlight the potential of this metabolite as a sustainable alternative for weed management, supporting the development of novel bioherbicides. Full article

Glyphosate is a broad-spectrum herbicide widely used. After years of extensive usage, many weed species have developed resistance due to both target-site (TSR) and non-target-site resistance mechanisms (NTSRs). Alopecurus myosuroides is a competitive weed species. Greenhouse monitoring trials in Germany have revealed reduced glyphosate efficacy against some populations of Alopecurus myosuroides. In a foregoing dose–response study, individual plants from four out of six tested populations survived full (1800 g a.i. ha⁻¹) or double (3600 g a.i. ha⁻¹) glyphosate dose rates permitted, suggesting the presence of tolerant biotypes with yet unknown resistance mechanisms. Our aim was to investigate the absorption and translocation patterns of glyphosate in these biotypes. The plants were first treated with ¹⁴C-glyphosate, and ¹⁴C-glyphosate absorption and translocation were subsequently visualized by phosphorimaging and finally quantified by liquid scintillation counting. The results showed significant differences in the distribution of glyphosate in different plant organs, with significantly more being translocated out of the treated leaf in glyphosate-resistant compared to sensitive (S-) biotypes. The study’s findings are partly in contrast to previous studies that have found reduced translocation. Our study demonstrates the complex nature of glyphosate resistance and suggests further experiments to finally elucidate the underlying resistance mechanisms in the biotypes of the Alopecurus myosuroides studied. Full article

Pyroligneous acid (PA) or wood vinegar, a co-product of biomass pyrolysis, is thought to be beneficial for plant productivity and soils, with the potential to reduce otherwise harmful agrochemicals. Here, we review the evidence for the use of PA on plant growth and soil health parameters. The analysis includes 65 peer-reviewed studies with 171 (yield) and 123 (plant biomass) data sets, covering 33 different crops belonging to 6 plant groups. Significant positive, non-linear relationships between PA concentration, yield, and plant biomass were found at concentrations as low as 0.1%, with the optimum at around 0.5–1% and overall positive effects up to 6–11% (depending on the application type), but yield declines above these concentrations, suggesting herbicidal effects. Across the whole data set, yield and biomass increase by an average of 21% and 25%, respectively, and by an average of 31% at the optimum rate. The positive effect of PA is most pronounced for plant growth under sub-optimal conditions (salt, drought, and pathogens), while responses did not differ between plant groups. Soil organic matter content shows a small but significant positive response to PA application, but the amount of data is very small compared to the plant parameters. The major shortcomings identified include inconsistent measures of applied PA (amount and composition) and the short duration of experiments of typically only 1–2 growing seasons, which prevents analysis of long-term PA effects. Overall, the results of this review encourage further research on PA for sustainable agriculture. Full article

Annual grass weeds can provide significant competition to an establishing sown tropical perennial grass pasture. At least two years of grass weed control prior to sowing is required to reduce the weed seed bank. Pre-emergent herbicides used in summer cereals, such as atrazine or s-metolachlor with metcamifen seed safener, may reduce this preparation time. Two controlled-environment experiments were conducted to assess the potential for these pre-emergent herbicides to be used with several tropical perennial grasses. Experiment 1 tested the effect of metcamifen (400 g L⁻¹ a.i. at 0–2× label rate) on the emergence and vigor of Chloris gayana, Dichanthium aristatum, Digitaria eriantha and Panicum coloratum, with Sorghum bicolor as the control. Experiment 2 tested the effect of s-metolachlor (960 g ha⁻¹ a.i.) with metcamifen-treated or untreated seed, and atrazine (1800 g ha⁻¹ a.i.) on the emergence and early growth of the grasses. Metcamifen did not inhibit emergence or vigor of the grasses. Without metcamifen seed treatment, s-metolachlor reduced the growth of the tropical perennial grasses by 47–100%, while it had no such effect on S. bicolor. In contrast, there was no effect of atrazine on shoot yields of the grasses, nor of s-metolachlor when D. aristatum, D. eriantha and P. coloratum seed had been treated with metcamifen. The collective results indicate that the herbicide safener metcamifen does not reduce the viability of tropical perennial grass seed and provides some protection against s-metolachlor, albeit not complete protection at the rates used in our study. Atrazine did not affect emergence or early growth of the grasses. Full article

The current Common Agriculture Policy (CAP) foresees a reduction of 50% in the use of herbicides by 2030. This study investigates the potential of integrating remote sensing with a low-cost RGB sensor and variable-rate technology (VRT) to optimize herbicide application in a ryegrass (Lolium multiflorum Lam.) fodder crop. The trial was conducted on three 7.5-hectare plots, comparing a variable-rate application (VRA) of herbicide guided by a prescription map generated from segmented digital images, with a fixed-rate application (FRA) and a control (no herbicide applied). The weed population and crop biomass were assessed to evaluate the efficiency of the proposed method. Results revealed that the VRA method reduced herbicide usage by 30% (0.22 l ha⁻¹) compared to the FRA method, while maintaining comparable crop production. These findings demonstrate that smart weed management techniques can contribute to the CAP’s sustainability goals by reducing chemical inputs and promoting efficient crop production. Future research will focus on improving weed recognition accuracy and expanding this methodology to other cropping systems. Full article

Zero-tillage (ZT) is a conservation soil management approach which relies more heavily on herbicide application for weed control than in ploughed soil. Changes in soil management can influence the structure and organisation of pore space in soil, which drives changes in the transport of particulates and dissolved substances. Formulation of pesticides can be used to change the delivery of active ingredients to soil; however, it is currently unknown how changing the formulation of an herbicide can influence the transport properties between ZT vs. ploughing. We investigated the bioefficacy of two formulations of the herbicide atrazine, a pre- and post-emergence herbicide that inhibits photosystem II. Bioefficacy was assessed using physical measures and survival analysis of an early photosynthesis-dependent weed species, Amaranthus retroflexus L., over time, and soil pore network structure was assessed by analysing three-dimensional images produced by X-ray Computed Tomography. Increasing the herbicide application rate generally improved bioefficacy, though it was reduced in soils managed under ZT. Under herbicide-treated ZT samples, survival time was higher, ranging from 13.4 to 18.2 days compared with 12.6 to 15.4 days in ploughed samples, the mean dry plant mass was higher, ranging from 0.5 to 2.5 mg compared with 0.05 to 0.68 mg in ploughed samples, and the mean total plant length was higher, ranging from 1.73 to 12.1 mm compared with 0.2 to 5.45 mm in ploughed samples. Changes in the soil pore network previously demonstrated to be indicators of preferential transport were correlated with measures of bioefficacy, including pore thickness and connectivity density. Reduced atrazine efficacy under ZT is problematic considering the inherent reliance on chemical methods for weed control, we suggest that pursuing formulation strategies to alleviate potential risks of loss via preferential transport may be fruitful. Full article

Spring wheat was grown on a loess-derived Luvisol under the conditions of two farming systems (conventional and organic) and five forecrops (sugar beet, spring barley, red clover, winter wheat, and oat) over the period 2021–2023. In the conventional system, mineral NPK fertilization and pesticides (herbicides, fungicide, insecticide, and retardant) were applied at the recommended rates for wheat. Mechanical weed control was also used (double harrowing). In the organic system, the organic fertilizer Humac Agro was applied and the fields under the wheat were harrowed twice. No plant protection products were used under organic farming conditions. The organic system was proven to have an effect on reducing spring wheat yield, on average by 23%, compared to the conventional system (the grain yield was, respectively, 4.59 t ha⁻¹ compared to 5.96 t ha⁻¹). In spite of the lower yield potential, the organic cultivation of spring wheat significantly improved the quality and health-promoting parameters of this cereal grain. Except for the total nitrogen and potassium content, the organic system contributed to a significant increase in the grain content of total dietary fiber (by 0.89 p.p.), o-dihydroxyphenols (by about 19%), and polyphenols (by about 12%), and increased the content of the following elements: Se, Mg, Ca, Cu, Mn, Fe, and Zn. Among the forecrops, red clover and sugar beet had the most beneficial effect on grain quality (including the amino acid composition and EAAI index), followed by oat (especially under organic farming conditions). The other wheat forecrops (spring barley and winter wheat) clearly deteriorated the yield and quality of spring wheat grain. To sum up the obtained research results, appropriate management of organic spring wheat cultivation (forecrop sugar beet or red clover, Humac Agro fertilizer) contributes to high grain nutritional quality relative to the conventional system and also reduces the yield gap relative to conventional farming. Full article

In plasticulture production systems, the conventional practice involves broadcasting pre-emergent herbicides over the entire surface of raised beds before laying plastic mulch. However, weed emergence predominantly occurs through the transplant punch-holes in the mulch, leaving most of the applied herbicide beneath the plastic, where weeds cannot grow. To address this issue, we developed and evaluated a precision spraying system designed to target herbicide application to the transplant punch-holes. A dataset of 3378 images was manually collected and annotated during a tomato experimental trial at the University of Florida. A YOLOv8x model with a p2 output layer was trained, converted to TensorRT^® to improve the inference time, and deployed on a custom-built computer. A Python-based graphical user interface (GUI) was developed to facilitate user interaction and the control of the smart sprayer system. The sprayer utilized a global shutter camera to capture real-time video input for the YOLOv8x model, which activates or disactivates a TeeJet solenoid for precise herbicide application upon detecting a punch-hole. The model demonstrated excellent performance, achieving precision, recall, mean average precision (mAP), and F1score exceeding 0.90. Field tests showed that the smart sprayer reduced herbicide use by up to 69% compared to conventional broadcast methods. The system achieved an 86% punch-hole recognition rate, with a 14% miss rate due to challenges such as plant occlusion and variable lighting conditions, indicating that the dataset needs to be improved. Despite these limitations, the smart sprayer effectively minimized off-target herbicide application without causing crop damage. This precision approach reduces chemical inputs and minimizes the potential environmental impact, representing a significant advancement in sustainable plasticulture weed management. Full article

Straw mulching in conservation tillage farmland can effectively promote land utilization and conservation. However, in this farming mode, surface straw suppresses weed growth, affecting weed size and position distribution and obscuring the weeds, which hampers effective weed management in the field. Accurate weed identification and localization, along with efficient herbicide application, are crucial for achieving precise, efficient, and intelligent precision agriculture. To address these challenges, this study proposes a weed detection model for a targeted spraying system. Firstly, we collected the dataset of weeds in a straw-covered environment. Secondly, we proposed an improved YOLO v5s network, incorporating a Convolutional Block Attention Module (CBAM), FasterNet feature extraction network, and a loss function to optimize the network structure and training strategy. Thirdly, we designed a targeted spraying system by combining the proposed model with the targeted spraying device. Through model test and spraying experiments, the results demonstrated that while the model exhibited a 0.9% decrease in average detection accuracy for weeds, it achieved an 8.46% increase in detection speed, with model memory and computational load reduced by 50.36% and 53.16%, respectively. In the spraying experiments, the proposed method achieved a weed identification accuracy of 90%, a target localization error within 4%, an effective spraying rate of 96.3%, a missed spraying rate of 13.3%, and an erroneous spraying rate of 3.7%. These results confirm the robustness of the model and the feasibility of the targeted spraying method. This approach also promotes the application of deep learning algorithms in precision weed management within directional spraying systems. Full article

Boron-doped diamond electrodes (BDDEs) offer a highly efficient pathway to mineralize recalcitrant compounds due to their reduced energy requirements, fewer chemical inputs, and mechanical stability. In this work, the electrochemical degradation of paraquat (PQ) and diquat (DQ) was studied using an undivided cell (Condiacell^®-type) at circumneutral pH, and under galvanostatic control. The roles of applied current density, volumetric flow rate, and herbicide concentration were systematically studied through a central composite design (CCD) using a closed-flow reaction setup. Under the best operating conditions (i.e., for PQ: 1.6 mA/cm², 80 mL/min, and 70 mL/min, and 70 mg/L; and for DQ: 1.5 mA/cm², 80 mL/min, and 73 mg/L), a spectrophotometric analysis evidenced that the herbicides were satisfactorily removed (ca. 100%) while mineralization degrees were above 90%. Furthermore, the produced effluents yielded significant increases in seed germination and root length, which suggest a reduction in toxicity. Energy consumptions of 0.13 and 0.18 kWh/g of TOC are reported with the electrochemical cells for the PQ and DQ treatments, respectively. The PQ and DQ treatments by electrooxidation are estimated to emit nearly 2.7 and 38.9 kg CO₂/m³ of water treated, with a cost around USD 250/m³. Carbon emissions could be greatly decreased for PQ (0.28 kg CO₂/m³) and DQ (0.40 kg CO₂/m³) if electricity were generated from renewable resources. Although this study suggests that the use of BDDE can be considered as a green alternative for agrochemical removal due to lower carbon emissions, the environmental profile of the process is determined by the degree of renewability of the electrical grid of each country or region. Full article