Non-chemical Weed Control Methods Research Articles

Nonchemical Aquatic Weed Control Methods: Exploring the Efficacy of UV-C Radiation as a Novel Weed Control Tool.

Aquatic weeds, including invasive species, are a worldwide problem. The presence of aquatic weeds poses several critical issues, such as hindering the continuous flow of water in irrigation channels and preventing the proper distribution of adequate water quantities. Therefore, effective control measures are vital for agriculture and numerous downstream industries. Numerous methods for controlling aquatic weeds have emerged over time, with herbicide application being a widely used established method of weed management, although it imposes significant environmental risks. Therefore, it is important to explore nonchemical alternative methods to control existing and emerging aquatic weeds, potentially posing fewer environmental hazards compared with conventional chemical methods. In this review, we focus on nonchemical methods, encompassing mechanical, physical, biological, and other alternative approaches. We primarily evaluated the different nonchemical control methods discussed in this review based on two main criteria: (1) efficiency in alleviating aquatic weed problems in location-specified scenarios and (2) impacts on the environment, as well as potential health and safety risks. We compared the nonchemical treatments with the UV-C-radiation-mediated aquatic weed control method, which is considered a potential novel technique. Since there is limited published literature available on the application of UV-C radiation used exclusively for aquatic weed control, our review is based on previous reports of UV-C radiation used to successfully control terrestrial weeds and algal populations. In order to compare the mechanisms involved with nonchemical weed control methods, we reviewed respective pathways leading to plant cell death, plant growth inhibition, and diminishing reemergence to justify the potential use of UV-C treatment in aquatic habitats as a viable novel source for aquatic weed control.

Evaluation of non-chemical weed control methods in wheat (Triticum aestivum L.)

Evaluation of non-chemical weed control methods in wheat (Triticum aestivum L.)

Chemical control and herbicide resistance of hairy fleabane (Erigeron bonariensis L.) in Jordan.

The effect of paraquat, oxadiazon and oxyfluorfen herbicides was tested on two populations of hairy fleabane (Erigeron bonariensis L.), collected from a date palm orchard at Tal al-Ramil (Central Jordan Valley) and al-Twal (Northern Jordan Valley) sites using the recommended rates (0.5, 1.25 and 0.792kg a.i ha-1 for each herbicide, respectively) and 10-fold (5, 12.50 and 7.92 kg a.i. ha-1, respectively) under glasshouse conditions. Results showed that the date palm weed population was resistant to the three herbicides at both application rates and al-Twal site population was highly susceptible. Two field experiments were conducted to evaluate the effectiveness of 12 herbicides in controlling the weed in the date palm orchard during the spring of 2017, revealed that E. bonariensis resists paraquat (0.5, 1.0 and 1.5 kg a.i. ha-1), oxadiazon (1.25 kg a.i. ha-1) and oxyfluorfen (0.792 kg a.i. ha-1) herbicides. None of the three herbicides was effective against the weed and treated plants continued to grow normally similar to those of untreated control. Ten-fold higher rates of these herbicides failed to control the weed. The effect of other tested herbicides was variable with bromoxynil plus MCPA (buctril®M), 2,4-D- iso-octyl ester, glyphosate, glyphosate trimesium and triclopyr being the most effective and completely controlling the weed at recommended rates of application. It is concluded that the tested populations of E. bonariensis developed resistance to paraquat, oxadiazon and oxyfluorfen but control of the weed was possible using other herbicides with different mechanisms of action. Herbicide rotation or other nonchemical weed control methods have been suggested to prevent or reduce the buildup and spread of resistant populations of this weed. These results represent the first report of herbicide resistance of E. bonariensis in Jordan.

Assessment of Processes and Challenges of Beekeeping in Edo State, Nigeria

The study was carried out to assess the process and challenges of beekeeping in Edo State, Nigeria. Four Local Government Areas were selected based on the presence of beekeepers in the areas. Data were obtained using a structured questionnaire. A total of 40 respondents were randomly and proportionately selected from the four (4) Local Governments and used for the study. Descriptive statistics were used as analytical tools. The result indicates that all the respondents (100%) were male and, most of them (65%) had 20 colonies and above. Also, most of the beekeepers were in their active and productive age (80%) group, less than 40 years. Shortage of forage, absconding of bees, agrochemicals, high cost of beekeeping equipment, pest, agrochemicals, and theft were some of the major problems militating against beekeeping in the study area. The prevalent pest identified by the beekeepers were wax moth, ants, termites, lizards, and spiders. It was recommended that there should be more training and awareness by extension agents to encourage people to participate in beekeeping in Edo State. Women should be encouraged to participate in beekeeping in Edo State. Government and non-governmental organizations in collaboration with the bee farmers’ cooperative groups should provide improved beekeeping technologies at a subsidized rate to the farmers in order to encourage them. The issue of Wax moth pests reported by farmers should be looked into and control measures suggested. The use of pesticides and herbicides should be discouraged and non-chemical methods of insect and weed control should be encouraged

A Review of Chemical Weed Control Practices in Christmas Tree Production in the United States

Christmas trees are sensitive to weed competition, especially during establishment. In initial stages of the tree crop, weeds can utilize available soil moisture and trees may succumb to drought stress. In later stages, weeds can even interfere with production practices. Non-chemical weed control methods alone may not provide effective weed control. Chemical weed management strategies involve the use of preemergence and postemergence herbicides at the right timing and application rates. There are many herbicides that are used in Christmas tree production in the United States, and each has specific application guidelines and weed control spectra. Moreover, crop trees vary in tolerance by species and tree age. Growers need to be careful while applying herbicides as many of these chemicals can cause injury to Christmas trees. Repeated application of herbicides with the same mechanism of action has resulted in development of herbicide resistance among several weed species. Managing herbicide resistance has now become an important issue. More research is required on identifying and managing herbicide resistance among weed species in Christmas tree production. Future research needs to focus on herbicide and mulch combinations, herbicide rotations, and tank mixing different herbicides with different mechanisms of actions and how these affect Christmas tree varieties.

Comparative Analysis of Microwave and Electric Arc as a New Method in Weed Control

The increase in the demand for organic production and the adverse effects of chemicals used in agriculture have brought non-chemical weed control methods to the fore. Among these methods, the most studied ones are microwave and electric arc methods. It has been determined in studies that microwaves and electric current, when applied at the correct power level and for sufficient time, biologically inactivate weeds, all kinds of unwanted plants and seeds. In this study, the mortality rates caused by microwave energy and electric current (arc) methods in some plants applied under laboratory conditions were compared. Studies have shown that the effectiveness of microwave and electric arc methods depends on the selected current, voltage, power level and exposure time. It is thought that the electric arc method is easier and more economical in terms of application in the field than the microwave method. Another purpose of this study is to remind agricultural policy makers and decision makers of the importance of alternative weed control methods and to ensure that they make policies in this direction.

Comparative Analysis of Microwave and Electric Arc as a New Method in Weed Control

The increase in the demand for organic production and the adverse effects of chemicals used in agriculture have brought non-chemical weed control methods to the fore. Among these methods, the most studied ones are microwave and electric arc methods. It has been determined in studies that microwaves and electric current, when applied at the correct power level and for sufficient time, biologically inactivate weeds, all kinds of unwanted plants and seeds. In this study, the mortality rates caused by microwave energy and electric current (arc) methods in some plants applied under laboratory conditions were compared. Studies have shown that the effectiveness of microwave and electric arc methods depends on the selected current, voltage, power level and exposure time. It is thought that the electric arc method is easier and more economical in terms of application in the field than the microwave method. Another purpose of this study is to remind agricultural policy makers and decision makers of the importance of alternative weed control methods and to ensure that they make policies in this direction.

Weed management in greengram: A review

Greengram [Vigna radiata (L.) Wilczek], also known as mungbean, is extensively cultivated in India and other Asian countries. Being rich in protein, its grains are an important daily dietary component. Weeds are a major limiting factor in production of greengram that lead to a drastic reduction in yield. The presence of hardy weeds and slow initial crop growth compound this problem. Different strategies incorporating non-chemical and chemical methods have been practiced for efficient weed control in greengram. Non-chemical control methods include straw mulch (12–63% reduction in weed biomass), narrow row spacing (60–92% reduction in weed biomass), method of sowing (1–20% reduction in weed biomass), tillage practices (58% reduction in weed biomass), the frequency and rate of irrigation and fertilizer application (13–23% reduction in weed biomass), timing of hand weeding and selection of cropping system. Chemical control methods include the many herbicides with different selectivity and efficiency available for use in greengram. For efficient weed control, herbicides should be applied at the recommended rate and time in order to avoid inhibiting growth, symbiotic properties (number of nodules, dry weight of nodules, leghaemoglobin content in nodules) and grain yield in greengram crop. In this review, different weed management strategies including nonchemical and chemical weed control methods have been reviewed for their ability to control weeds in greengram. Furthermore, their influence on growth, symbiosis, yield and nutrient uptake of greengram, soil microflora and residual effect on succeeding crops have also been reviewed.

A proposal to design and develop a microwave weed controller for agricultural use

Problems based on agricultural activities are increasingly adversely affecting the environment and living health mostly due to chemical inputs used which cause concerns globally. One of the non-chemical weed control methods is the microwave weed control method. The purpose of this research is to propose an environmentally friendly agricultural machine design that can be an alternative to harmful chemicals used in weed control. In this study, microwave generators (magnetron) receive their energy from a generator fed from the tractor shaft. Multiple magnetrons, control, and leakage unit, and waveguides operating at 2.45 GHz ISM will be used. The design includes a magnetic shunt transformer, a high voltage capacitor, a filter, and a cooling fan with each magnetron where microwave leaks that occur during applications can be controlled and magnetron activities can also be monitored. Field applications and tractor working conditions will be analyzed and the device will be re-designed and developed according to the needs. In this study, unlike the other studies, more than one magnetron will be used and the device is designed for open agricultural areas applications. This design and application area differences are the most important feature that distinguishes this study from others, and it is made for the first time. Its use is expected to occur in all countries with similar characteristics for agricultural production.

A Review on Parameters Affecting the Choice of Alternative (Non-Chemical) Weed Control Methods

Chemical using as a weed control method is the most preferred method in weed control because they are easily accessible, easily applicable and inexpensive. But, with the new environment-friendly regulations, the importance of non-chemical methods has increased all over the world. In addition, organic farm and non-chemical agricultural methods are gaining importance with increasing social environment and health awareness. Non-chemical methods, called, "alternative methods” have been one of the most popular research subjects in recent years. The physical removal or killing of weeds is usually done by hand or by means designed tools for this task, which varies from country to country. The most known modern non-chemical weed control methods are; electric current, microwave heating, superheated steam, infrared using, pneumatic system, freeze-drying, laser cutting, and fresnel lens systems. The most popular of these methods are; electric current method and microwave heating. In electric current and microwave heating methods, there are no chemical residues in soil and plants after application. It has been shown in the studies that, the microwave weed control method can destroy weeds and seeds when appropriate frequency, sufficient time and required power level are selected. Therefore, in the selection of non-chemical weed control methods, some important parameters of plant and soil should be known. The electrical and dielectric properties of plants and soil such as, electrical resistance (R), impedance (Z), dielectric constant (ε’), loss factor (ε’’), the permittivity (permeability ( and conductivity (σ) should be known especially in microwave and electric current methods. The other parameters like the age, height and density of the plant is an issue to be considered in all control methods. But, the moisture content of soil and plant may not be taken into consideration in hot water and steam applications. For the freeze-drying method, the moisture and water content of the plant and soil must also be taken into account.

Review on Parameters Affecting the Choice of Alternative (Non-Chemical) Weed Control Methods

Chemical using as a weed control method is the most preferred method in weed control because they are easily accessible, easily applicable and inexpensive. But, with the new environment-friendly regulations, the importance of non-chemical methods has increased all over the world. In addition, organic farm and non-chemical agricultural methods are gaining importance with increasing social environment and health awareness. Non-chemical methods, called, "alternative methods” have been one of the most popular research subjects in recent years. The physical removal or killing of weeds is usually done by hand or by means designed tools for this task, which varies from country to country. The most known modern non-chemical weed control methods are; electric current, microwave heating, superheated steam, infrared using, pneumatic system, freeze-drying, laser cutting, and fresnel lens systems. The most popular of these methods are; electric current method and microwave heating. In electric current and microwave heating methods, there are no chemical residues in soil and plants after application. It has been shown in the studies that, the microwave weed control method can destroy weeds and seeds when appropriate frequency, sufficient time and required power level are selected. Therefore, in the selection of non-chemical weed control methods, some important parameters of plant and soil should be known. The electrical and dielectric properties of plants and soil such as, electrical resistance (R), impedance (Z), dielectric constant (?’), loss factor (?’’), the permittivity (permeability ( and conductivity (?) should be known especially in microwave and electric current methods. The other parameters like the age, height and density of the plant is an issue to be considered in all control methods. But, the moisture content of soil and plant may not be taken into consideration in hot water and steam applications. For the freeze-drying method, the moisture and water content of the plant and soil must also be taken into account.

The influence of non-chemical weed control methods on sugar beet productivity and quality parameters

A long-term stationary field experiment was carried out at the Experimental Station of Aleksandras Stulginskis University (Vytautas Magnus University Agriculture Academy since 2019) in 2017. The following sustainable weed control methods were examined: 1) inter-row loosening (control treatment); 2) inter-row cutting and mulching with weeds; 3) inter-row cutting and mulching with Persian clover; 4) inter-row cutting and mulching with white mustards; 5) interrow cutting and mulching with spring barley. The alternatives to weed control often reduced the yields of sugar beet roots significantly, however, when mulching with white mustard the decrease in fertility was not essential. Non-chemical weed control measures in most cases had an insignificant effect on the parameters of sugar beet quality – the content of Na, K and alpha-amino N. The most significant sugar content (16.34 and 16.26%) was found in sugar beets, which were grown applying interrow mulch of spring barley and weed (P < 0.05). Although insignificant, but the largest index of sugar beet leaf area was found in the experimental plots, where inter-row cutting out and mulching with white mustard were applied. Comparing non-chemical weed control systems, the highest amount of white (crystalline) sugar (4.96 ha–1) was derived from the sugar beet that was grown using white mustard mulch.

The impact of non-chemical weed control methods on the disease occurrence in the organically grown winter oilseed rape crop

The impact of non-chemical weed control methods on the disease occurrence in the organically grown winter oilseed rape crop

A herbicide resistance risk matrix

Herbicide resistance is of increasing concern, especially as there is a lack of new modes of action. An assessment of resistance risk has been a key part of the pesticide authorisation process in most European countries since the early 2000's. However, little guidance is provided on how to quantify these risks. The risk matrix described here presents a quantitative approach to the evaluation of the resistance risk posed by the use of herbicides. The inherent, ‘unmodified’ risk is first assessed by ranking herbicides and major target weed species on a scale from low to high resistance risk, based largely on published information. In practice, agronomic management practices (‘modifiers’) will reduce the risk and these are factored into the matrix. Modifiers can include management strategies relating to herbicide use as well as non-chemical methods of weed control. By assigning defined impact factors to possible agronomic modifiers, the overall resistance risk of a herbicide under defined use conditions can be quantified. The approach, although simple, appears robust and produces realistic assessments of the resistance risks associated with four contrasting test scenarios. The aim is to achieve a better harmonisation of herbicide resistance risk assessment across Europe. Although the matrix has a European legislative focus, the approach and principles are relevant in other parts of the world where the extensive use of herbicides is a relatively recent development, and where there is currently limited knowledge and expertise on herbicide resistance and the evaluation of resistance risks.

Impact of non-chemical weed control methods on the soil and sugar beet root chemical composition

Impact of non-chemical weed control methods on the soil and sugar beet root chemical composition

The impact of non-chemical weed control methods and biopreparations on winter oilseed rape preparation for over-wintering and productivity

The current study was aimed to establish the impact of non-chemical weed control methods (thermal, mechanical andsmothering) and biopreparations on winter oilseed rape (Brassica napus L.) preparation for over-wintering and productivity under the conditions of the organic farming system. During the 2014–2016 period, a field experiment was conducted at the Experimental Station of Aleksandras Stulginskis University on Calc(ar)i-Endohypogleyic Luvisol (LVg-n-w-cc). The field experiment treatments were the following: Factor A – non-chemical weed control methods: 1) thermal (water steam), 2) mechanical (inter-row loosening), 3) smothering (self-regulation, sowing with narrow inter-rows); Factor B – application of biopreparations: 1) without application, 2) with application. During the period of autumn vegetation, in the smothering method plots, where the winter oilseed rape crop density was 1.5–2.4 times lower than that in the plots of thermal and mechanical weed control methods, the significantly highest aboveground mass of plant, number of leaves per plant, diameter of root collar, root area, total root length, root biomass of plant and leaf area of plant were determined, and in 2015 the highest chlorophyll index was measured in the leaves. In 2014 the application of biopreprations in the smothering method plots significantly increased the aboveground mass of plant (41.3%), the total root length (33.2%) and the root biomass of plant (28.0%). In 2004 the diameter of winter oilseed rape root collar depended on the leaf area of plant (r = 0.83, P < 0.05) and the root area of plant (r = 0.86, P < 0.05), and in 2015 it depended on the leaf area of plant (r = 0.89, P < 0.05), the root area (r = 0.99, P < 0.01), the total root length (r = 0.98, P < 0.01) and the root biomass of plant (r = 0.99, P < 0.01). Positive, strong and very strong, and statistically significant relationships were established between the leaf area of oilseed rape and the root area, the total root length and the root biomass of plant. In the spring of 2015, during the renewed oilseed rape vegetation stage, the highest crop density (98.0 units m–2) and over-wintering (96.0%) were obtained in the plots of the mechanical weed control method in combination with biopreparations. In the spring of 2016, different nonchemical weed control methods and biopreparations did not have any significant effect on the oilseed rape over-wintering and the crop density. In 2015, different non-chemical weed control methods did not have any significant influence on oilseed rape biometric parameters before harvesting. In 2016, in the smothering method plots a significantly lower mass of oilseed rape and the number of branches per plant were formed compared to those of other used treatments. The highest number of pods per plant was determined in the smothering method plots in combination with biopreparations. In 2015 biopreprations in the smothering method plots significantly increased the 1 000 seed mass, and in 2016 they increased the number of pods per plant, respectively 7.2 and 35.6%. In the droughty year of 2015, the significantly highest winter oilseed rape seed yield was recorded in the plots of the mechanical weed control method, and in the moist year of 2016, the highest yield was in the smothering method plots with biopreparations. In 2015 biopreprations significantly increased the oilseed rape seed yield in the plots of thermal and mechanical weed control methods, and in 2016 they increased the yield in the smothering method plots, respectively 43.4, 25.1 and 51.5%. In 2015 the winter oilseed rape seed yield depended on the crop density (r = 0.86, P < 0.05) and the plant height (r = 0.94, P < 0.01), and in 2016 it depended on the number of pods per plant (r = 0.98, P < 0.01) and the plant height (r = 0.85, P < 0.05).

Mulch Type and Depth Influences Control of Three Major Weed Species in Nursery Container Production

Two commonly used management practices for weed control in container plant production are hand pulling and herbicide applications. There are problems associated with these methods including crop phytotoxicity and environmental concerns associated with off-target movement of herbicides. Other nonchemical weed control methods could reduce herbicide-based environmental concerns, mitigate herbicide-resistance development, and improve the overall level of weed control in container nursery production. Readily available tree-mulch species, eastern red cedar (Juniperus virginiana), ground whole loblolly pine (Pinus taeda), chinese privet (Ligustrum sinense), and sweetgum (Liquidambar styraciflua) were harvested, chipped, and evaluated at multiple depths with and without the herbicide dimethenamid-p. Pine bark mini-nuggets were also evaluated. Mulches were applied at depths of 1, 2, and 4 inches and evaluated over three 30-day periods for their effectiveness in suppressing spotted spurge (Chamaesyce maculata), long-stalked phyllanthus (Phyllanthus tenellus), and eclipta (Eclipta prostrata). After 30 days, herbicide/mulch combinations, as well as mulch treatments alone, had reduced weed fresh weight 82% to 100% with 1 inch of mulch. By 168 days after treatment, dimethenamid-p had lost all efficacy, and mulch depth was the only factor that still had significant effects, reducing spotted spurge fresh weight by 90%, 99.5%, and 100% with depths of 1, 2, and 4 inches, respectively. The economics of mulch weed control will depend on variables such as available time, nursery layout, location, and availability of resources, equipment, among others. Regardless of variable economic parameters, data from this study reveals that any of these potential mulch species applied at a depth of at least 2 inches will provide long-term weed control in nursery container production.

Effects of Woody Mulches and Dimethenamid-P on Container Grown Ligustrum japonicum and Viburnum macrocephalum

Current weed control practices in nursery container plant production consist primarily of hand weeding and application of preemergence herbicides. Non-chemical weed control methods, such as mulches, could reduce herbicide use, reduce potential environmental concerns from offsite herbicide movement, and decrease the expense of weed control. Before implementation, alternative methods of weed control must be evaluated for effects on the growth of common container-grown species. Mulches made from readily available tree species, including eastern red cedar (Juniperus virginiana), ground whole loblolly pine (Pinus taeda), Chinese privet (Ligustrum sinense), and sweetgum (Liquidambar styraciflua), were evaluated at multiple depths with and without the herbicide dimethenamid-P (Tower®). Wax-leaf ligustrum (Ligustrum japonicum) and snowball viburnum (Viburnum macrocephalum) treated with dimethenamid-P, averaged over mulch treatments, had up to 7% less growth compared to non-herbicide treated plants, but marketability was not affected. Mulch species and depth had no effect on plant growth. Results indicate that these readily available mulch species can be applied at depths up to 10.2 cm (4 in) for weed control in container plant production.

Using simulation models to investigate the cumulative effects of sowing rate, sowing date and cultivar choice on weed competition

With the increasing pressure on crop production from the evolution of herbicide resistance, farmers are increasingly adopting Integrated Weed Management (IWM) strategies to augment their weed control. These include measures to increase the competitiveness of the crop canopy such as increased sowing rate and the use of more competitive cultivars. While there are data on the relative impact of these non-chemical weed control methods assessed in isolation, there is uncertainty about their combined contribution, which may be hindering their adoption. In this article, the INTERCOM simulation model of crop/weed competition was used to examine the combined impact of crop density, sowing date and cultivar choice on the outcomes of competition between wheat (Triticum aestivum) and Alopecurus myosuroides. Alopecurus myosuroides is a problematic weed of cereal crops in North-Western Europe and the primary target for IWM in the UK because it has evolved resistance to a range of herbicides. The model was parameterised for two cultivars with contrasting competitive ability, and simulations run across 10 years at different crop densities and two sowing dates. The results suggest that sowing date, sowing density and cultivar choice largely work in a complementary fashion, allowing enhanced competitive ability against weeds when used in combination. However, the relative benefit of choosing a more competitive cultivar decreases at later sowing dates and higher crop densities. Modeling approaches could be further employed to examine the effectiveness of IWM, reducing the need for more expensive and cumbersome long-term in situ experimentation.

Winter oilseed rape and weed competition in organic farming using non-chemical weed control

One of the reasons why the area sown with oilseed rape in organic farms is not expanding is problems with weed, disease, and pest control as well as low seed yield. There is a lack of investigations on oilseed rape cultivated in an organic system, especially employing innovative weed control methods. To fill this gap in knowledge, field experiments were conducted at the Experimental Station of Aleksandras Stulginskis University in 2012–2013 with the aim of identifying and assessing the impact of different non-chemical weed control methods (thermal – TWC, mechanical – MWC and smothering – SMT) on weed competitiveness in winter oilseed rape (Brassica napus L.) crops during the autumn vegetation period in an organic farming system with and without the use of plant bio-activators in a soil with a regular (23–25 cm) (1st experiment) and with a thickened (48–50 cm) (2nd experiment) humus layer. It was found, that compared with thermal and mechanical weed control, in the treatment using smothering weed control and spraying with plant bio-activators or not spraying, the density of winter rape crop in the soil with a regular humus layer was significantly (P ≤ 0.05) lower (1.2 to 5.3 times); in the soil with a thickened humus layer, the density of winter rape crop was 1.5 to 5.9 times lower. In winter oilseed rape during autumn vegetation period, 20–22 weed species were found, including 18–19 annuals. Stellaria media (L.) Vill., Veronica arvensis L., Sinapis arvensis L. and Capsella bursa-pastoris (L.) Medik. were the predominant weeds. In the soil with a regular and a thickened humus layer, thermal and mechanical weed control significantly (P ≤ 0.05) decreased the number of weed seedlings (1.1 to 1.9 times) when plant bio-activators were used compared with the smothering treatment. Weed control in the smothering treatment in the soil with a regular and thickened humus layers was not effective. Mechanical weed control was more efficient than thermal. Application of plant bio-activators increased the efficiency of the thermal weed control.