Use Of Herbicides Research Articles

Impacts of credit constraints on adoption of risk management strategies and income of maize farmers in Northern Nigeria

PurposeA correlation has been shown in the literature between credit constraints and the adoption of agricultural technologies, technical efficiencies and measures for adapting to climate change. The relationship between credit constraints, risk management strategy adoption and income, however, is not well understood. Consequently, the purpose of this study was to investigate how credit constraints affect the income and risk management practices adopted by Northern Nigerian maize farmers.Design/methodology/approachCross-sectional data were collected from 300 maize farmers in Northern Nigeria using a multi-stage sampling technique. Descriptive statistics, seemingly unrelated regression and double hurdle regression models were the analysis methods.FindingsThe results showed that friends and relatives, banks, “Adashe”, cooperatives and farmer groups were the main sources of credit in the study area. The findings also revealed that the sources of risk in the study area included production risk, economic risk, financial risk, institutional risk, technological risk and human risk. In addition, the risk management strategies used to mitigate observed risks were fertilizer application, insecticides, planting of disease-resistant varieties, use of herbicides, practising mixed cropping, modern planning, use of management tools as well as making bunds and channels. Furthermore, we found that interest rate, farm size, level of education, gender and marital status were significant determinants of statuses of credit constraints while the age of the farmer, gender, household size, primary occupation, access to extension services and income from maize production affected the choice and intensity of adoption of risk management strategies among the farmers.Research limitations/implicationsThe study concluded that credit constrained status condition of farmers negatively affected the adoption of some risk management strategies and maize farmers’ income.Practical implicationsThe study concluded that credit constrained status condition of farmers negatively affected the adoption of some risk management strategies and maize farmers’ income. It therefore recommends that financial service providers should be engaged to design financial products that are tailored to the needs of smallholder farmers in the study area.Originality/valueThis paper incorporates the role of constraints in influencing farmers’ decisions to uptake credits and subsequently their adoption behaviours on risk management strategies. The researcher approached the topic with a state-of-the-art method which allows for obtaining more reliable results and hence more specific contributions to research and practice.

Wild Oat ( Avena fatua ): Crop Mimicry and Herbicide Resistance

Abstract Wild oat ( Avena fatua ) is a weed species that through crop mimicry survive in conventional managed farmlands, particularly in cereal crops such as wheat and barley. Adaptation of wild oat likely dates back around 9000 years when domestication of cereal species began in the Fertile Crescent and around the Mediterranean Sea. So far, wild oat has been described as a troublesome weed in 44 countries across temperate parts of the world. Wild oat reduces crop yields due to its competition for nutrients, water and light. Variable seed dormancy results in early maturing plants that add to the soil’s seed bank, and later maturing plants that contaminate the harvested grain. Since wild oat seeds resembles cereal grain, they are difficult to remove by mechanical seed cleaning. Seed lots contaminated with wild oat seeds are downgraded since it reduces the suitability as food and feed. Contaminated seedlots used for planting is a source of long distance spread of the weed. Herbicide application is an important part of wild oat control in areas with intensive wheat and barley production. Herbicide labels typically recommend the optimal size of wild oat seedlings and crop plants for best control. However, timing of an application can be difficult when wild oat plants are at different growth stages. The majority of herbicides are grouped according to the mode-of-action in cells of weed plants either inhibiting specific enzymes or entire metabolic pathways. Repeated use of herbicides with the same mode-of-action creates a selection pressure that can result in development of wild oat populations resistant to these herbicides. There is a direct relationship between the number of wild oat plants treated with herbicides and the risk of selecting for resistant plants. Thus, best management practices (BMP) aim to reduce the number of wild oat seed in the field, and include rotating between herbicides with different mode-of-action, and following recommendations on herbicide labels regarding plant growth stages and dosage. Cultural practices include rotating crop species and optimizing crop health, planting of weed-free seed, and cleaning of machinery between fields. Wild oat’s adaptations for crop mimicry and herbicide resistance make it problematic to manage but incorporating BMPs into an integrated approach can help. Information © His Majesty the King in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada.

Sunflower Broomrape (Orobanche cumana Wallr.) and Weeds in Sunflower Crops with Minimized Tillage in a Steppe Ecotype Crop Rotation

Abstract An important reserve for increasing the productivity of agricultural production is a scientifically based crop structure and the use of rational crop rotations, which implement the optimal ratio of agroecological standards. The aim of the research was to determine the influence of elements of agrotechnical measures, in particular, the saturation of crop rotations with sunflower, soil tillage system on the number and species composition of various agrobiological groups of weeds in sunflower crops, including the weed parasite sunflower broomrape (Orobanche cumana Wallr.). Weed control measures and the spread of the parasitic weed sunflower broomrape in sunflower crops have been carried out according to the methods generally accepted in agriculture and weed science. The scheme of the experiment included crop rotations with saturation in the structure of sunflower sowing of 12.5, 20, 25, 33.3, 50, 100% and three systems of basic tillage: moldboard plowing, disc tillage, and no-tillage. As a result of the research, it has been found that the systems of disc tillage and no-tillage cause an increase in the number of weeds in sunflower crops compared to the moldboard plowing by 1.3–1.5 times. On average, over the years of research, the abundance of weeds in the plots when using disk tools was 10.4–15.1 pcs./m2, moldboard plowing was 7.1–12.4 pcs./m2, and before harvesting was 2.6–5.2 and 4.1–12.4 pcs./m2. The highest degree of sunflower broomrape damage has been observed in 2-fields crop rotation (winter wheat—sunflower) and permanent sunflower cultivation, as 16.0–32.4% of affected sunflower plants have been observed here. The intensity of sunflower broomrape damage to sunflower plants was higher in the moldboard plowing system and amounted to 1.2–8.3 pcs./per plant, which exceeded disc tillage and no-tillage by 1.2–1.6 times. The maximum seed yield of 2.92–2.95 t/ha has been obtained in 8- and 5-fields rotations with the use of moldboard plowing. The lowest yields of sunflower seeds were in short-rotation crop rotations with a sunflower saturation of 50% in the structure of sown areas and permanent cultivation and amounted to: moldboard plowing—1.75–2.21 t/ha, disk tillage—1.57–2.01 t/ha, and no-tillage—1.49–1.95 t/ha. Given the urgency of supplying the global market with sunflower oil, in the future it is necessary to increase the concentration of sunflower in the structure of sown areas to 30-40% through the system of basic tillage, selection of resistant hybrids, and use of herbicides.

Tezcalera, a traditional agricultural system that promotes native wild and agrestal germplasm conservation

Background: Traditional agricultural systems in Mesoamerica are adaptations of ancient farmers to the complex and varied environments. Tezcalera represents one of them. Questions: How is the environmental context under which the tezcalera develop? Which management practices are followed in tezcalera? How do these management practices affect weeds' richness, composition, and abundance? How do these management practices contribute to the resilience of the agricultural system, the tropical dry forests, and to the maintenance of subsistence resources? Studied species: Weeds growing in tezcaleras with different management. Study site and dates: Zumpahuacán, State of México, 2020-2021 Methods: Twenty-four collaborators were interviewed about the environmental, technological, and cultural aspects of tezcalera. We recorded weeds' richness, composition, and abundance in seven plots with different management histories. Results: Tezcaleras originate from the slash-burn process and follow different paths: tlacolol-milsol-shallow plot, potrero, and recently, Agave crop. We recorded 161 morphospecies from 45 botanical families; 95 % were native to tropical dry forests. Twenty-five species are endemic to the Balsas region, and thirty-four are at risk. Richness and abundance varied between tezcaleras, where tlacolol plots exhibited the highest values. Plant composition was similar; 65 % had intangible or tangible values. Conclusions: Tezcalera is a biocultural unit and a resilient agroecosystem. Traditional practices remain and positively impact the richness and composition of native weeds. The uncontrolled use of herbicides and the introduction of Agave crop are displacing traditional crops and modifying traditional practices, risking local agrobiodiversity.

The ilv2 gene, encoding acetolactate synthase for branched chain amino acid biosynthesis, is required for plant pathogenicity by Leptosphaeria maculans

BackgroundControl of blackleg disease of canola caused by the fungus Leptosphaeria maculans relies on strategies such as the inhibition of growth with fungicides. However, other chemicals are used during canola cultivation, including fertilizers and herbicides. There is widespread use of herbicides that target the acetolactate synthase (ALS) enzyme involved in branched chain amino acid synthesis and low levels of these amino acids within leaves of Brassica species. In L. maculans the ilv2 gene encodes ALS and thus ALS-inhibiting herbicides may inadvertently impact the fungus.Methods and resultsHere, the impact of a commercial herbicide targeting ALS and mutation of the homologous ilv2 gene in L. maculans was explored. Exposure to herbicide had limited impact on growth in vitro but reduced lesion sizes in plant disease experiments. Furthermore, the mutation of the ilv2 gene via CRISPR-Cas9 gene editing rendered the fungus non-pathogenic.ConclusionHerbicide applications can influence disease outcome, but likely to a minor extent.

Multi-medium residues and ecological risk of herbicides in a typical agricultural watershed of the Mollisols region, Northeast China

The widespread use of herbicides impacts non-target organisms, promotes weed resistance, posing a serious threat to the global goal of green production in agriculture. Although the herbicide residues have been widely reported in individual environmental medium, their presence across different media has received scant attention, particularly in Mollisols regions with intensive agricultural application of herbicides. A systematic investigation was conducted in this study to clarify the occurrence of herbicide residues in soil, surface water, sediments, and grains from a typical agricultural watershed in the Mollisols region of Northeast China. Concentrations of studied herbicides ranged from 0.30 to 463.49 μg/kg in soil, 0.31–29.73 μg/kg in sediments, 0.006–1.157 μg/L in water, and 0.32–2.83 μg/kg in grains. Among these, Clomazone was the most priority herbicide detected in soil, sediments, and water, and Pendimethalin in grains. Crop types significantly affected the residue levels of herbicides in grains. Clomazone posed high ecological risks in soil and water, with 86.4 % of water samples showing high risks from herbicide mixtures (RQ > 1). These findings aid in enhancing our comprehension of the pervasive occurrence and potential ecological risks of herbicides in different media within typical agricultural watersheds, providing detailed data to inform the development of targeted mitigation strategies.

Laser weeding of common weed species

The massive use of herbicides since the 1950s has resulted in increasing problems with herbicideresistant weeds and pollution of the environment, including food, feed, and water. These side effects have resulted in political pressures to reduce herbicide application. The European Commission aims to reduce the use and risk of chemicals and more hazardous pesticides in the EU. Therefore, new weed control methods are in demand. Laser weeding might be an alternative to replace or supplement herbicides and other weed control methods in an Integrated Weed Management (IPM) strategy. This work aimed to investigate how increasing laser energy affected common weeds when the apical meristem was exposed to irradiation at the early stages of development. A 50 W thulium-doped fibre laser with a diameter of 2 mm and a wavelength of 2 µm was used. The highest efficacy of laser irradiation was achieved when the grass weed (Alopecurus myosuroides) had one leaf and the dicot species were at the cotyledon stage. There was a large difference between the species’ susceptibility to irradiation probably caused by differences in morphology and growth habit. At the 4-leaf stage, most of the species regrew after irradiation. Laser weeding may be a solution to replace or supplement other weed control methods in some crops, but in general the weeds must be irradiated when they are at the cotyledon to 2-leaf stage to avoid regrowth.

Intelligent crop management system for improving yield in maize production: evidence from India

PurposeManaging weeds and pests in cropland is one of the major concerns in agriculture that greatly affects the quantity and quality of the produce. While the success of preventing potential weeds and pests is not guaranteed, early detection and diagnosis help manage them effectively to ensure crops’ growth and healthDesign/methodology/approachWe propose a diagnostic framework for crop management with automatic weed and pest detection and identification in maize crops using residual neural networks. We train two models, one for weed detection with a labeled image dataset of maize and commonly occurring weed plants, and another for leaf disease detection using a labeled image dataset of healthy and infected maize leaves. The global and local explanations of image classification are obtained and presentedFindingsWeed and disease detection and identification can be accurately performed using deep-learning neural networks. Weed detection is accurate up to 97%, and disease detection up to 95% is made on average and the results are presented. Further, using this crop management system, we can detect the presence of weeds and pests in the maize crop early, and the annual yield of the maize crop can potentially increase by 90% theoretically with suitable control actionsPractical implicationsThe proposed diagnostic models can be further used on farms to monitor the health of maize crops. Images obtained from drones and robots can be fed to these models, which can then automatically detect and identify weed and disease attacks on maize farms. This offers early diagnosis, which enables necessary treatment and control of crops at the early stages without affecting the yield of the maize cropSocial implicationsThe proposed crop management framework allows treatment and control of weeds and pests only in the affected regions of the farms and hence minimizes the use of harmful pesticides and herbicides and their related health effects on consumers and farmers.Originality/valueThis study presents an integrated weed and disease diagnostic framework, which is scarcely reported in the literature

Characterization of herbicide use practices in cereal agroecosystems in western Burkina Faso

The use of pesticides often leads to environmental contamination above acceptable levels. The level of contamination is related to poor pesticide application practices, in addition to the properties of pesticides and soil characteristics. The primary objective of this study was to characterize herbicides and their application practices in cereal crops in the regions of Hauts-Bassins, Sud-Ouest, Cascades, and Boucle du Mouhoun in Burkina Faso. A semi-structured questionnaire was used to collect and extract data from 617 cereal farmers in the four regions. During the survey, the identified herbicides were characterized using pesticide property databases. The survey shows that most cereal farmers in the regions are illiterate (58.18%) and have not received any training in pesticide use (84.28%). Only a small percentage of farmers (1.3%) consult technical services for the selection of herbicides to be used. The survey also revealed that 60% of farmers leave empty herbicide containers in the wild, 39.93% use water sources to clean sprayers, and 17.83% use them to prepare the spray mixture. A total of 25 active ingredients were identified in 117 commercial herbicide products with a total use of 8100 litres and 280 kg. Of the listed herbicides, 45.37% were not approved by the Sahel Pesticide Committee (CSP). Among the non-approved herbicides, 27.78% contained paraquat, atrazine, and acetochlor, which the CSP bans. The study shows that farmers do not follow good practices when using herbicides, which can contaminate different environmental compartments and cause harmful effects to non-target organisms.

Засоренность посевов яровой пшеницы при применении ресурсосберегающих технологий обработки почвы

The purpose of research is to study the influence of primary tillage systems on the weed infestation of spring wheat crops placed on green manure fallow in a five-field grain-fallow crop rotation. Objectives: to study the weed infestation of spring wheat crops; to establish the effectiveness of herbicide use; to determine the grain yield of spring wheat. The study was carried out in 2017–2022 in the conditions of the Krasnoyarsk forest-steppe on leached chernozem, which is characterized by an increased humus content (6.1–8.0 %) and a neutral reaction of the soil solution (pH – 6.1–7.0). The object of the study is spring wheat of the Novosibirskaya 15 variety. The research results showed that the bulk of weeds in the studied variants are represented by a group of young plants. Different tillage systems influenced the quantitative and species composition of weeds. When soil tillage is minimized, the number of weeds increases and their species composition changes. In spring wheat crops under the studied tillage options, the most numerous group of weeds were young ones. The most common species found in spring wheat crops were bedstraw (Galium aparine L.) and millet (Echinochloa crusgalli (L.). Their share in the total number of weeds in the variant with plowing was 71.4 %, without tillage – 81.4 %. There was a significant change in the share of biological groups of young and perennial weeds in the option without tillage during the study period. The share of young weeds in 2022 decreased compared to 2017 from 93.1 to 58.8 %, while the number of perennial weeds increased from 6.9 to 41.2 %.Over the years of the study (2017–2022), a change in the species composition of weeds was established. In the option without tillage, such species as yellow sow thistle, medicinal dandelion, hemlock, and small petal, which were absent in 2017, appear in spring wheat crops.

Assessing the bioaccumulation and translocation potential of vetiver grass for dioxins phytoremediation in Bien Hoa airbase, Viet Nam

Dioxins (PCDD/Fs) are well-known toxic organic pollutants that accumulate in the environment and the food chain, imposing a risk to human health and the ecosystem. Due to the use of dioxin-contaminated herbicides during the US-Vietnam War, there are several hotspots in Vietnam with very high levels of dioxins. Phytoremediation has been increasingly developed in recent decades because of its low cost and environmental-friendly aspect. Vetiver grass is a plant that can remediate both organic and inorganic agents. In this study, the uptake and translocation of dioxins in Vetiver grass (Chrysopogon zizanioides) from the dioxin-contaminated soil was investigated in a field experiment on the Bien Hoa airbase, Vietnam. An experimental area was divided into six plots, of which three were planted with Vetiver grass and three served as control plots, with the initial dioxin concentrations as following: FC2>FC3>FC1>FT2>FT3>FT1. Vetiver grass had grown well on the dioxin-contaminated soils, yielding high biomass and the level of dioxins in the roots of vetiver grass was positively correlated (r2 = 0.67; p<0.01) with its growth rate. During the first year of cultivation, Vetiver grass had the greatest capacity to efficiently accumulate dioxin. Accumulation occurs in the roots, with BAF>1 throughout the entire experiment period for FT3, and in the first year for FT1 and FT2. The dioxin translocation from the roots to the shoots was significantly lower than the BAF and less than one (TF<1), with the first and second sampling times having the highest values compared to the others. Dioxin concentrations do not provide a reliable indicator of its bioavailability but numerous other factors, such as physicochemical properties of the soil and microbes. Our study aims to contribute significant insights to capability of Vetiver grass to accumulate and translocate dioxins, hence the arsenal of dioxin remediation. Furthermore, we envisage translating our findings into practical applications in other areas, considering optimized planting techniques, growth conditions, and long-term sustainability.

Exploring the interaction of weed control management and crop structure on maize yield in the wide range of Mexican cropping systems.

Abstract Herbicide use as the main driver to control weeds is increasingly being questioned. Several countries have adopted policies to control the use of herbicides, challenging multiple actors to restore, expand, or develop alternative solutions for weed management that consider the specific needs of each agroecosystem. Testing alternative weed management (agroecological) in a wide range of cropping systems can include comparing them with herbicide use and exploring their potential interaction with different cropping systems and cropping structures. The objectives of our study were: i) to assess weed control treatments in different cropping systems (CSYS), ii) to explore interactions between weed treatment and cropping structure (CSTR) and investigate how these interactions affect weed and maize covers evolution, and iii) to assess weed control treatments and CSTR effects on final grain yield. Weed management treatments did not differ in grain yield in a wide range of CSYS. Agroecological management required a greater number of practices. The timing of weed control practices (Ve and V6) was an important factor for both agroecological and herbicides treatments and for different genotypes. Weed management treatments did not interact with CSTR to define grain yield. However, it explained between 28 to 60% of grain yield variability. We highlight the importance of genotype and plant density elections for grain yield determination. We also highlight that the apparent response of genotypes and density on weeds in experimental conditions is not evident in field conditions. It is still necessary to develop more complex models that can include factors such as the decision-making of farmers and technicians.

Assessment of tolerance to glyphosate and glufosinate in genetically modified cotton shoots

Destruction of the harvest of cotton stalks should be done after it. However, destruction by ploughing prevents continuing with direct sowing, which makes chemical management an ally in soil conservation. The objective was to identify the most effective dose of 2,4-D, associated with different herbicides and the timing of administration for the control of transgenic cotton shoots for tolerance to glyphosate and glufosinate. The treatments consisted of the use of the herbicide 2,4-D, alone at doses of 670 and 1 340 g ha-1, and associated with the herbicides carfentrazone, flumiclorac, chlorimuron, flumioxazin and imazethapyr at three application times: 0 days after mechanical mowing (0 DAMM), 25 DAMM, and 0 DAMM + 25 DAMM. Regrowth evaluations were performed at 15, 30, and 45 days after the first and second applications, determining the dry biomass of the shoots. In terms of herbicide use time, the best results are obtained when they applied at 0 DAMM + 25 DAMM. Higher doses of 2,4-D (1 324 g ha-1) make it more efficient; in relation to herbicides, variations were perceived in their behavior depending on the time of evaluation, the application, and the dose of 2,4-D used. During the last measurement period, 45 days after application, 2,4-D+carfentrazone and 2,4-D+flumiclorac had the lowest dry shoot masses. The experiment was conducted in 2014. It was concluded that there is a lower rate of cotton regrowth when the application of the herbicides is repeated at 0 DAMM and 25 DAMM. The 1 324 g ha-1 dose of 2,4-D is more efficient. 2,4-D+carfentrazone and 2,4-D+flumiclorac promoted lower dry mass 45 days after administration of the treatments.

Ecological weed management and square planting influenced the weed management, and crop productivity in direct-seeded rice

Herbicide use may pose a risk of environmental pollution or evolution of resistant weeds. As a result, an experiment was carried out to assess the influence of different non-chemical weed management tactics (one hoeing (HH) at 12 DAS followed by (fb) one hand weeding at 30 DAS, one HH at 12 DAS fb Sesbania co-culture and its mulching, one HH at 12 DAS fb rice straw mulching @ 4t ha−1, one HH at 12 DAS fb rice straw mulching @ 6 t ha−1) on weed control, crop growth and yield, and economic returns in direct-seeded rice (DSR). Experiment was conducted during kharif season in a split-plot design and replicated thrice. Zero-till seed drill-sown crop (PN) had the lowest weed density at 25 days after sowing (DAS), while square planting geometry (PS) had the lowest weed density at 60 DAS. PS also resulted in a lower weed management index (WMI), agronomic management index (AMI), and integrated weed management index (IWMI), as well as higher growth attributes, grain yield (4.19 t ha–1), and net return (620.98 US$ ha–1). The cultivar Arize 6444 significantly reduced weed density and recorded higher growth attributes, yield, and economic return. In the case of weed management treatments, one HH at 12 DAS fbSesbania co-culture and its mulching had the lowest weed density, Shannon-weinner index and eveness at 25 DAS. However, one hoeing at 12 DAS fb one hand weeding at 30 DAS (HH + WH) achieved the highest grain yield (4.85 t ha–1) and net returns (851.03 US$ ha–1) as well as the lowest weed density at 60 DAS. PS × HH + WH treatment combination had the lowest weed persistent index (WPI), WMI, AMI, and IWMI, and the highest growth attributes, production efficiency, and economic return.

A survey of listeners' perceptions of an extension-produced invasive plant podcast

Science communication and university Extension initiatives are evolving in response to society’s needs and an ever-changing digital landscape. The UF/IFAS Center for Aquatic and Invasive Plants (CAIP) has recently launched a podcast called Working in the Weeds (WITW). We surveyed podcast listeners to find out their motivations for listening and asked for their feedback on current episodes and future content. The survey revealed that a majority of respondents were individuals who work in the world of invasive plants. Many respondents were introduced to the podcast through work and listen to learn more about relevant research and information, to feel connected to the Center, and to be entertained. Overall, the respondents were satisfied with the podcast production elements and the variety of episode styles. Based on open-ended responses, listeners described that the podcast shares science in a meaningful way and the Center should continue producing episodes that highlight invasive plant research. Some respondents suggested future episodes should cover specific invasive plants, environmental impacts, herbicide use and safety, management techniques, and social issues surrounding invasive plant management.

Features of the protection of phaseolus vulgaris crops from weeds

Goal. To determine the effect of herbicides on the weediness of crops and the yield of Phaseolus vulgaris seeds in the conditions of the Right Bank Forest Steppe of Ukraine. Methods. Informational and analytical (collection of materials and analysis of literary sources), field research (setting up experiments, observing the development of plants, determining biometric indicators, accounting for the number of weeds, collecting and determining the structure of the harvest), mathematical and statistical (processing of research results). The field experiment design included weeded and weed-protected plots to compare the development of common bean plants under different growing conditions. The results. It was established that the dominant weeds among cereals were chicken millet and gray mouse millet, and among dicotyledonous weeds - ragweed, white quinoa, common sedge, black solanum, field mustard, etc. The use of herbicide protection significantly improves the yield of Phaseolus vulgaris. The obtained yield increased on average by 1.93 - 2.01 t/ha compared to the weeded control. Conclusions. Weeding can significantly reduce the yield of common bean crops by competing for resources such as light, water and nutrients. Weed control helps conserve these resources for the Phaseolus vulgaris and increase its yield. The use of herbicides is an effective method of weed control, which promotes optimal growth of Phaseolus vulgaris. The increase in yield due to the application of herbicide protection can offset the costs of purchasing and applying the herbicide. It is important to consider the effectiveness of specific herbicides when choosing crop protection methods. Different herbicides can have different spectrums of action, that is, be effective against different types of weeds. The right choice will help optimize results and save costs. Therefore, weed control in common Phaseolus vulgaris crops through the application of herbicide protection is an important and effective strategy that can increase the yield and economic efficiency of common bean cultivation technology.

Common use herbicides increase wetland greenhouse gas emissions

Wetlands play a disproportionate role in the global climate as major sources and sinks of greenhouse gases. Herbicides are the most heavily used agrochemicals and are frequently detected in aquatic ecosystems, with glyphosate and 2,4-Dichlorophenoxyacetic acid (2,4-D), representing the two most commonly used worldwide. In recent years, these herbicides are being used in mixtures to combat herbicide-tolerant noxious weeds. While it is well documented that herbicide use for agriculture is expected to increase, their indirect effects on wetland greenhouse gas dynamics are virtually unknown. To fill this knowledge gap, we conducted a factorial microcosm experiment using low, medium, and high concentrations of glyphosate or 2,4-D, individually and in combination to investigate their effects on wetland methane, carbon dioxide, and nitrous oxide fluxes. We predicted that mixed herbicide treatments would have a synergistic effect on greenhouse gases compared to individual herbicides. Our results showed that carbon dioxide flux rates and cumulative emissions significantly increased from both individual and mixed herbicide treatments, whereas methane and nitrous oxide dynamics were less affected. This study suggests that extensive use of glyphosate and 2,4-D may increase carbon dioxide emissions from wetlands, which could have implications for climate change.

Optimizing Weed Control: A Study on the Influence of Drone Sprayer Altitude in Herbicide Application

This research aims to determine the spraying distance of herbicides using a drone sprayer to achieve effective weed control. The use of herbicides is crucial to managing the competition for plant nutrients that threaten crop yields. The study analyzes the herbicide distribution patterns on plants sprayed using a drone with a flying speed of 3 m/s, utilizing a flat fan nozzle at different flying distances. During spraying activities, a compact weather station was employed to record environmental conditions, including air temperatures around 33.4-34.4 °C, relative humidity between 56.2-64.3%, wind speeds of 0.1-1 m/s, and wind direction from the southwest or south. There was no rainfall during the spraying sessions. The research results significantly contribute to the development of herbicide spraying technology using drones by carefully considering environmental conditions. Chlorophyll content was measured using the Soil-Plant Analysis Development (SPAD) chlorophyll meter and the Normalized Difference Vegetation Index (NDVI) through drone mapping. The drone sprayer at a 1-meter distance, covering an area of 600 m2, and using a 10 ml herbicide mixed with 10,000 ml water effectively reduced chlorophyll in weed plants. Multispectral data showed significant changes with a shift to red indicating non-vegetative areas after herbicide spraying. There was a decrease in average chlorophyll values measured at 2, 4, 6, 8, and 10 days post-spraying, with the lowest recorded on plots with a 1-meter spraying distance (average chlorophyll value of 19.62 SPAD). Therefore, the drone sprayer at a 1-meter distance proved effective in controlling weeds and reducing chlorophyll in non-target plants, making a crucial contribution to the development of herbicide spraying technology using drones and improving efficiency in agricultural management.

Cytotoxic Effect of Clethodim Exposure on Liver Cells&

Clethodim, a herbicide group pesticide, is classified as a toxicity class II agent. The development toxicity, immunotoxicity, neurotoxicity and reproductive toxicity of this herbicide have been demonstrated in zebrafish and rat. There are no in vitro studies on the hepatoxic effects of clethodim. In this study, for the first time, clethodim was tested with liver cell line models. THLE-2 and B129 cells were treated with a wide range of clethodim for 96 hours. After that, its hepatoxic effects were evaluated by MTT and SRB analyses. Both assays revealed that the cellular proliferation was strikingly decreased with the dose dependent manner. Especially, 1000 µg/ml dose of the clethodim exposure supressed the cellular proliferation at a %90 and %75 for B129 and THLE-2 cells. Moreover, a significant reduction was acquired in both cells number and volume with the high doses of this cyclohexanedione class herbicide. These cytotoxic impacts can be strongly related to the herbicide elaved oxidative stress. In the light of our results, the long and high doses of clethodim exposure has a hepatoxic effect and its toxic target organ is be liver. Hence, further studies on the use of clethodim-based herbicides are urgently needed.

Sustainable alternative to irrigated maize monoculture in a maize-dominated cropped area: Lessons learned from a system experiment

Maize is the most-produced food crop in the world and is grown in intensive rotations or in monoculture (continuous maize) systems. As maize production has expanded massively across the world, many concerns have emerged about its local environmental and other global impacts. Agronomists have designed innovative cropping systems and assessed them using system experiments to make arable systems more sustainable. However, knowledge is still lacking on the sustainability of innovative cropping systems compared to highly intensive systems such as irrigated maize-based monoculture. Here, we present the assessment results of a nine-year system experiment in Alsace, France, developed to compare an innovative system based on a diversified rotation and innovative management practices (three-year rotation of maize/soybean/winter wheat (plus a cover crop) combined with reduced tillage) with a continuous maize reference system. The results cover a six-year assessment period following an initial three-year design period. Classic criteria, such as profitability, workload, pesticide use, fossil energy consumption and nitrate leaching, were assessed along with other less studied criteria, such as pesticide leaching risk, soil structure, soil chemical quality and soil biological activity. Sustainability – which includes environmental, social and economic dimensions – was assessed with the MASC 2.0 method. Overall sustainability was substantially enhanced in the innovative system (5 out of 7 sustainability classes) in comparison with the low level of the reference system (2 out of 7). This was due to a clear improvement in the environmental performance (from 2 out of 5 to 5 out of 5) while social performance was high in both systems (4 out of 5) and economic performance was low (2 out of 5) due to very low contribution to economic development. Nevertheless, the innovative system had a major drawback: lower profitability, especially when scenarios included high maize prices. Furthermore, herbicide use on maize was higher in the innovative system than in the reference one. Avenues for progress, such as encouraging stakeholder participation at the assessment stage or additional innovations such as multiple cropping, are suggested.