Chemical Weed Control Methods Research Articles

Weed Management Methods for Herbaceous Field Crops: A Review

Weeds compete with crops for water and nutrients and can adversely affect crop growth and yield, so it is important to research effective weed control methods. This paper provides an overview of the impact of weeds on crop yield and describes the current state of research on weed management in field herbaceous crops. Physical weed control mainly refers to thermal technologies represented by flame weed control and laser weed control, which can efficiently and accurately remove weeds. Mechanical weed control requires a combination of sensor technologies, machine vision technology, and high-precision navigation to improve weed control accuracy. Biological weed control relies heavily on plant extracts and pathogens to create herbicides, but it is costly, and some can be toxic to mammals. Chemical weed control is a common method, resulting in environmental pollution and weed resistance. To reduce the use of chemical herbicides, scholars have proposed integrated weed management strategies, which combine biological control, control of the seed bank, and improve crop competitiveness. Integrated weed management strategies are considered to be the future direction of weed management. In conclusion, physical, mechanical, biological, and chemical weed control methods are commonly used in weed management. Each method has its applicable scenarios, and the implementation of integrated weed management strategies can lead to better weed control, improving crop yield and quality. The main objective of this review is to organize the research progress on weed management methods for herbaceous crops in the field and to provide a reference for the agricultural sector to develop weed control strategies. Specifically, this paper categorizes weed management methods into four groups, discusses and presents the advantages and disadvantages of the aforementioned weed control methods, and discusses future research directions.

Assessing Phytotoxic Effects of Herbicides and Their Impact on Potato Cultivars in Agricultural and Environmental Contexts

Phytotoxicity refers to the capacity of chemical substances or environmental factors to have a negative impact on plants. This is a crucial issue in both the context of crop cultivation and environmental protection. The research results were based on a 3-year field experiment conducted at an experimental station in Jadwisin (52°28′ N, 21°02′ E) on loamy soil. The experiment was set up using a randomized sub-block design in a split–split–plot arrangement with three replications. The first-order factor consisted of potato cultivars, while the second-order factors were weed control methods: (1) without protection; (2) mechanical weed control, extensive mechanical treatments to close rows; (3) Sencor 70 WG—pre-emergence (PRE) of potatoes; (4) Sencor 70 WG + Titus 25 WG + Trend 90 EC—PRE of potatoes; (5) Sencor 70 WG—post-emergence (POST) of potatoes; (6) Sencor 70 WG + Titus 25 WG + Trend 90 EC—POST of potatoes; (7) Sencor 70 WG + Fusilade Forte 150 EC—POST of potatoes; and (8) Sencor 70 WG + Apyros 75 WG + Atpolan 80 SC—POST of potatoes. The phytotoxic effects of herbicides on potato plants and weeds were assessed every 7 days, starting from the date when the first signs of damage appeared until they stabilized or disappeared. Phytotoxic damage to potato and weed plants was caused by the chemical weed control methods used. The response of potato plants to herbicides was significantly related to the genetic traits of the cultivars and meteorological conditions in the years of research. Phytotoxicity is an important aspect in both agriculture and environmental protection. Research on its mechanisms and impact will enable the development of effective plant protection strategies and the preservation of ecosystem balance.

A conceptual evaluation of a weed control method with post-damage application of herbicides: A composite intelligent intra-row weeding robot

Weed management is an important part of crop production. Efficient weeding can help increase the yield and quality of crops. However, traditional weeding methods often fail to consider weeding quality and environmental protection. To address these shortcomings, a weeding method in which herbicides are applied after injury to weed tissue was developed, and an intelligent intra-row weeding robot was designed to evaluate the performance of this method. In control experiments, the proposed innovative weeding method showed a significantly better weed removal rate than purely mechanical weeding; its greatest contribution was to reduce the number of mechanical weeding operations, thereby reducing energy consumption and damage to the environment. Moreover, compared with chemical weeding approaches, the proposed method achieved a good weed removal rate while minimizing the use of herbicides, thereby reducing crop damage, weed resistance, and environmental pollution. In the final maize (Zea mays L.) test area, the robot traveled at a speed of 2.0 km/h and operated at a transmission efficiency of 60 frames per second. Moreover, the robot achieved a weed removal rate of 90.0% and a crop damage rate of 1.9%. Even better performance was obtained in a test area with Chinese cabbage, with a 94.5% weed removal rate and a 0.8% crop damage rate. Meanwhile, this method used only 15.3% of the herbicide required by traditional chemical weed control methods. Thus, the environmental protection properties of the intelligent intra-row weeding robot are more sustainable than those of conventional weeding methods, and the robot can achieve good performance in small-area fields.

Assessment of knowledge and patterns of weedicide and personal protective equipment usage among farmers in some cocoa farming communities in Ghana

The inability of farmers to adhere to the precise usage pattern of weedicides and personal protective equipment (PPE) in cocoa cultivation has been a challenge to cocoa production, the environment and human health. We conducted a study to determine the usage pattern of weedicides and PPE in some cocoa-growing communities in the Western North region of Ghana. We collected data from 92 cocoa farmers distributed in five communities using a semi-structured questionnaire and descriptive statistics was employed in analysing the data in the form of frequency, percentages and p values. The results indicated a significant difference (P < 0.05) in all the socio-economic characteristics of the farmers where most of the smallholder farmers were of old age. The majority (84%) of the farmers used both manual and chemical methods of weed control in their farms. Farmers' choice of weed control method was significantly influenced by their level of education, use of protective clothing and their socio-economic characteristics. Farmers’ knowledge of weedicide usage, mode of application, rate of application and time of application was low. Wearing of protective clothing, wellington boots and overalls were common among farmers during weedicide application. Yet farmers complained of body irritation, severe headaches, catarrh, and body aches after weedicide usage. This is an indication of incomplete or improper use of personal protective equipment (PPE) by the farmers who were not aware of the dangers associated with the use of weedicides on their health. Based on these health problems and other related issues, Ghana Cocoa Board (COCOBOD) has discouraged cocoa farmers from the use of weedicides in the cocoa ecosystem. Instead, COCOBOD has provided slashers for use by farmers.

EFFECTS OF WEED CONTROL METHODS ON WEEDS AND PRODUCTIVITY OF RANGE GRASSES IN SEMI-ARID KENYA

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; Weeds are a common occurrence and challenge in different crops eventually influencing crop development and yields. Weed control and management are key in enhancing the productivity of cultivated pastures. In semi-arid Kenyan drylands, the main methods employed for weed management are manual cultural practices and recently, the application of commercial herbicides. &lt;strong&gt;Objective:&lt;/strong&gt; To evaluate the effects of two weed control methods on weed characteristics and productivity of four rangeland grasses commonly used in reseeding and pasture improvement in a semi-arid environment. &lt;strong&gt;Methodology:&lt;/strong&gt; In a randomized complete block design in a field experiment, we determined the effects of two weed control methods (manual and herbicide use) in four rangeland cultivated grasses. These are Buffel grass (&lt;em&gt;Cenchrus ciliaris&lt;/em&gt;), Horsetail grass (&lt;em&gt;Chloris roxburghiana&lt;/em&gt;), Masaai love grass (&lt;em&gt;Eragrostis superba&lt;/em&gt;) and Bush rye (&lt;em&gt;Enteropogon macrostachyus&lt;/em&gt;). Weed characteristics (species, density, diversity and weed biomass,) were evaluated, as well as the effectiveness of the weed control methods in the grasses. &lt;strong&gt;Results:&lt;/strong&gt; Broad-leaved weeds and annual grasses were prevalent in the established grasses. Generally, higher grass dry matter yields were obtained in &lt;em&gt;Cenchrus ciliaris&lt;/em&gt; grasses (2.05 t h&lt;sup&gt;-1&lt;/sup&gt;) while lowest yields were in &lt;em&gt;Chloris roxburghiana&lt;/em&gt; (1.2 ton ha&lt;sup&gt;-1&lt;/sup&gt;). Weed management interventions increased biomass production in the grasses by a mean of 19% in general. The mean yield increase varied with species and weed control method ranging from 8-39%. Weed control methods significantly reduced weed density, diversity and eventually weed biomass within the grass species. The efficacy of manual weed control and chemical application was in the range of 27-74%. &lt;strong&gt;Implications: &lt;/strong&gt;Weed control is, therefore, necessary if one is to realize higher productivity and returns in cultivated pasture and fodder systems in semi-arid environments. &lt;strong&gt;Conclusion:&lt;/strong&gt; Both chemical and manual control methods of weed control are important and effective approaches to manage weeds in pasture systems in semi-arid environments.&lt;strong&gt; &lt;/strong&gt;&lt;/p&gt;

Studies on weed species, effect of cultural and chemical weed control methods on the growth performances of Allium cepa

Allium cepa (Onions) is one of the major vegetables that is consumed all over the world after tomatoes due to is active compounds but weeds infestation during growth phase are the major challenge faced by the farmers which result in a very poor growth and yield of this spice. In this study, the conventional hand weeding practices were compared with weedicide pendimethalin to control different weeds and the morphological characters such as; number, size, height, neck area and fresh weight of the onions bulbs planted at Department of Plant Science and Biotechnology, Botanical Garden, KSUSTA. Twelve (12) weeds of different family were found and identified from the experimental field namely; Urena lobata, Eragrostis tremula, Amaranthus viridis, Senna occidentalis, Cenchruse chintus, Mitracarpus scaber, Commelina lanata, Zornia latifolia, Cassia tora, Sida cordifolia, Cleome viscosa and Euphorbia thyamifolia. In all, the treatments used cultural, chemical and integrated methods had shown a positive significant effect on weed control and yield of onion. This study revealed that cultural control (hand weeding) is the best method of weed, control as it provides maximum weed control in the tested vegetable as well as higher yield

Different Aspects of Weed Management in Maize (Zea mays L.): A Brief Review

Maize yield and weed concentration have a long history of reciprocal correspondence. The maize crop plant and weed species compete ruinously for nutrients, space, light, and water essential for their progress and advancement. The losses due to weed and methodologies of weed management have been discussed in this review. Reports have estimated around a 37% global loss in total maize production due to weeds. Among the different available weed control methods, chemical methods have become the new common in today’s world. A major upswing in interest in chemical methods of weed control from people all over the world can be deduced from surveys. The monetary forces that are the foremost objectives guiding our choices in crop production practices play a major role in this stimulation of increasing interest. These changes are not in the least befitting for the long term, as the overexploitation of the herbicides has an adverse effect on the environment and causes dismissal of the productivity of the soil, although being market-driven and favorable in the beginning. Since none of the single approach methods can work well enough on maize crops, integrated weed management and biological methodologies are recommended through several reports. In contrast to various weed management strategies, a significant gain in the academic attention of biological control methods can be reckoned from reports over the past few years. Many research projects are also currently underway.

Pollen-mediated flow of herbicide resistance genes in Beckmannia syzigachne.

Beckmannia syzigachne (Steud.) Fernald has evolved herbicide resistance due to the long-term sole use of herbicides and has become a dominant weed in wheat fields in the middle and lower reaches of the Yangtze River in China. In addition to the selection pressure imposed by herbicides, pollen-mediated gene flow (PMGF) has been reported to cause the spread of herbicide resistance between populations within a certain range in some farmland weeds. It is not clear whether the same is true for the self-pollinated grass weed B. syzigachne. In this study, we confirmed and quantified the level of PMGF in B. syzigachne through concentric circle planting and herbicide resistance tests. Results show that when the B. syzigachne pollen donor was close to the recipient (0.5m), the average gene flow was 0.66%. Gene flow was detected as far as 10m (the farthest distance studied) and decreased exponentially with increasing distance, which could be described by a double exponential decay model. Temperature also affected gene flow, whilst the average level of gene flow in all directions of wind was similar and wind speed caused insignificant difference in gene flow. The results of this study confirmed that PMGF can occur between B. syzigachne populations in adjacent fields. Although the level of resistance spreading by pollen was low, especially across long distance, the results were relevant for smallholding farms, which is the dominant form of agricultural operation in China. It is therefore important to take proactive measures and integrate chemical and ecological weed control methods to prevent the spread of resistant B. syzigachne via both seeds and pollens. © 2022 Society of Chemical Industry.

Productivity of tillage loosening and separating machines in an aggregate with tractors of various capacities

Currently, chemical methods of weed control are increasingly being replaced by mechanical weeding. One of the promising mechanical devices for weed control is a rotary loosening and separating stratifier. This tillage machine can provide high quality tillage to a depth of up to 18 cm. Its performance is determined by the width of the grip of the gun and the speed of movement and is limited by the traction capabilities of the tractor. Using the Goryachkin formula for the traction resistance of a tillage machine, the authors obtained the dependence of productivity on the width of the grip and the speed of movement at different depths of tillage. The obtained dependencies on the example of tractors John Deere 8330, HTZ 16131-05 and MTZ 1523.3 showed the presence of a pronounced maximum, which led to the solution of the optimization problem. The article presents a method for calculating the optimal width of the grip and the speed of movement that ensure the maximum productivity of the tillage machine, depending on the depth of processing and the specific resistance of the soil. The use of optimal parameters of the tillage machine allows you to increase its productivity by 2–3 times.

Investigation of the effect of non-uniform heat distribution of microwave on the mortality rates of some plants

Weeds, cause significant losses in agricultural production and are mostly controlled by herbicides, which are harmful to the environment. An alternative method that can be applied instead of these chemicals that pollute the soil and water is the microwave weed control method. But, one of the main problems with the microwave weed control method is the non-uniform heat distribution. This study aims to investigate the effect of non-uniform heat distribution on the mortality rate in the microwave weed control method by the NDVI (Normalized Difference Vegetation Index) technique. The NDVI technique has been used for the first time in this study to determine the mortality rate in microwave weed control. Mortality rates in one-week germinated Lepidium sativum (cress) and Hordeum vulgare (barley) grasses that were exposed to microwave energy for 10, 20, and 30 seconds were measured. It was determined that a higher rate of mortality occurred in the uniform heat distribution condition, compared to the non-uniform heat distribution (p &amp;lt;0.05). Mortality rates in both Hordeum vulgare (barley) and Lepidium sativum (cress) grasses increased as the microwave application time increased. The highest mortality rate occurred in Lepidium sativum (cress) grass (69.81%) and Hordeum vulgare (barley) grass (61.01%) with uniform heat distribution for 30 seconds. In the non-uniform heat distribution for 10 seconds, an increase was observed in Hordeum vulgare (barley) grass compared to the control group (7.01%). As a result, it can be said that weed control with microwave energy has the potential to be a good “environmentally friendly alternative method” to chemical weed control methods.

Development of a Weeding Robot with Tubular Linear Electric Motors

The use of chemical methods of weed control is an effective means of weed control. However, the use of large amounts of herbicides leads to environmental pollution, contaminates food, and adversely affects the health of people working with chemical herbicides. The safest method is to mechanically remove weeds by pulling the rooted weeds out of the soil or cutting and driving the weeds under the soil. Robots use pneumatic, hydraulic, or electrical systems to control weed cutters. Electrical systems are more efficient than other systems. It is proposed to use a tubular linear electric motor to drive the weed remover. An experimental sample of a tubular linear electric motor has been manufactured. His experimental studies showed that at a current of 8 A, the mechanical force from the movement of the movable rod is 500 N, and this value is sufficient for an actuator for weed control. Based on the results of experimental studies, a scheme of a weeding robot with two tubular linear electric motors has been developed to drive the weed control mechanism in the horizontal and vertical planes.

REVIEW ON WEED CONTROL IN GLYPHOSATE TOLERANT MAIZE

Weeds are a constant nuisance for farmers, which steal space and nutrients from the crops. Weed management is the botanical component which attempts to stop noxious weeds from competing with desired flora and fauna including domesticated plants. It is preventing of non-native species competing with native species. Growth of various weeds has been major problem in the yield of many plants. It has also affected the growth and development of maize as it competes with the space and nutrients. Different weed management techniques have been introduced till date to increase the yield and to control the weeds, also, aiming less effect of the techniques on the main plant. Generally, preventive, biological, cultural, mechanical and chemical weed control methods are used. Advancements in plant biotechnology have allowed the development of a number of herbicide resistant crops which is a success in chemical weed management of the crops. They have provided the requisite tools to transform the plants to contain the foreign genes. Genetically engineered herbicide resistant crops have been widely planted globally since their introduction in 1995. These developments offer new approaches to managing weeds in cropping systems. This technology offers some advantages over currently used systems.

Future efficacy of pre-emergence herbicides in corn (Zea mays) is threatened by more variable weather.

BACKGROUNDBy 2050, weather is expected to become more variable with a shift towards higher temperatures and more erratic rainfall throughout the U.S. Corn Belt. The effects of this predicted weather change on pre‐emergence (PRE) herbicide efficacy have been inadequately explored. Using an extensive database, spanning 252 unique weather environments, the efficacy of atrazine, acetochlor, S‐metolachlor, and mesotrione, applied PRE alone and in combinations, was modeled on common weed species in corn (Zea mays L.).RESULTSAdequate rainfall to dissolve the herbicide into soil water solution so that it could be absorbed by developing weed seedlings within the first 15 days after PRE application was essential for effective weed control. Across three annual weed species, the probability of effective control increased as rainfall increased and was maximized when rainfall was 10 cm or more. When rainfall was less than 10 cm, increasing soil temperatures had either a positive or negative effect on the probability of effective control, depending on the herbicide(s) and weed species. Herbicide combinations required less rainfall to maximize the probability of effective control and had higher odds of successfully controlling weeds compared with the herbicides applied individually.CONCLUSIONSResults of this study highlight the importance of rainfall following PRE herbicide application. As rainfall becomes more variable in future, the efficacy of common PRE herbicides will likely decline. However, utilizing combinations of PRE herbicides along with additional cultural, mechanical, biological, and chemical weed control methods will create a more sustainable integrated weed management system and help U.S. corn production adapt to more extreme weather.© 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Weed science as a new discipline and its status in some South Asian universities and colleges: examples from Bangladesh, Bhutan, Nepal and Pakistan

Abstract Agriculture is the most important sector of the economy and livelihood in South Asia. Of the many biotic stresses in agriculture, weeds pose a continuous threat and cause considerable yield losses in the major crops. In the past, ample human labour was available for weed management in South Asia. However, in recent years, there has been a steady decline in labour availability in this region due to migration to other better-paying sectors. Thus, farmers are rapidly adopting less labour-intensive, chemical weed control methods. Adoption of chemical control methods requires formal and nonformal education in herbicide mode of action, safety and weed biology. We emphasize that sound formal and nonformal education in weed science is thus a necessity for this region as adoption of herbicides increases. In this paper, we review existing problems with weeds, current weed management options, herbicide use trends and development of curricula in weed science in academic institutions in Bangladesh, Bhutan, Nepal and Pakistan. We emphasize that herbicide resistance management programmes need to be developed before it becomes a major problem in the region.

Study on effect of weed management practices on weed dynamics and productivity of kharif maize

Field trials were conducted at Agricultural College and Research Institute, TNAU, Coimbatore, Tamilnadu, India, during two consecutive kharif (rainy) seasons of 2018 and 2019. The experiment was laid in a randomized block design different weed control methods viz., pre emergence (PE) atrazine at 0.5 kg a.i. ha-1 fb hand weeding (HW) at 20 DAS, PE atrazine at 0.5 kg a.i. ha-1 fb power weeder (PW) at 20 DAS, PE atrazine at 0.5 kg a.i. ha-1 + pendimethalin at 1 kg a.i. ha-1 (Tank mix), PE atrazine at 0.5 kg a.i. ha-1 + pendimethalin at 1 kg a.i. ha-1 fb HW at 20 DAS, early post emergence (EPOE) topramezone at 25.2 g a.i. ha-1, PE atrazine at 0.5 kg a.i. ha-1 fb EPOE topramezone at 25.2 g a.i. ha-1, EPOE tembotrione at 122 g a.i. ha-1, PE atrazine 0.5 kg a.i. ha-1 fb EPOE tembotrione 122 g a.i. ha-1, hand weeding twice at 20 and 40 DAS and control (weedy check) with 3 replications for each treatment. The results revealed that the experimental field was infested with all categories of weeds including grasses, broad-leaved weeds and sedges. Among them the most predominant weeds were Cynodon dactylon, Dactyloctenium aegyptium, Echinochloa colona, Amaranthus viridis, Digera arvensis and Trianthema portulacastrum. Among the chemical weed control methods PE atrazine at 0.5 kg a.i. ha-1 fb EPOE topramezone at 25.2 g a.i. ha-1 and PE atrazine 0.5 kg a.i. ha-1 fb EPOE tembotrione 122 g a.i. ha-1 recorded significantly lower weed density as well as weed dry weight of BLW, grasses, sedges and total weed at 90 DAS during 2018 and 2019, respectively. As a consequence of effective weed control, the above treatments recorded significantly higher weed control efficiency (WCE) and lower weed index (WI) during 2018 and 2019, at 90 DAS. These treatments were statistically comparable with hand weeding twice at 20 and 45 DAS. Uncontrolled weed growth in control (weedy check) recorded higher weed density and weed dry matter in maize crop during both the years of experimentation.

Fitosociología de malezas en plantaciones bananeras en el departamento del Magdalena, Colombia

Las malezas constituyen un factor limitante en la producción de banano en Colombia. Para contribuir a la fundamentación de su manejo, se propuso evaluar la estructura y diversidad de las comunidades de malezas en cuatro zonas productoras de banano (Alta, Media, Baja y Norte) en el departamento del Magdalena. Se realizaron levantamientos durante 2016 y 2017 mediante muestreo sistemático utilizando cuadrados de 1m2 en fincas seleccionadas en cada zona con método de control químico, cobertura y mecánico, y se calculó la frecuencia, densidad y dominancia de las malezas para estimar el índice de valor de importancia (IVI), la diversidad alfa y el índice de similitud de Bray-Curtis. Se identificaron 122 especies incluidas en 93 géneros y 39 familias. Poaceae y Cyperaceae presentaron mayor riqueza específica y Commelinaceae mayor IVI. Commelina erecta, Axonopus compressus y Melothria pendula fueron las especies de mayor importancia ecológica en las plantaciones. Los parámetros fitosociológicos difieren entre zonas y métodos de control. Las zonas con mayor y menor diversidad fueron Norte y Baja, respectivamente. Hubo mayor similitud entre las zonas Media y Baja, así como entre Media y Alta, en tanto, la Norte fue la más disímil. Pocas especies fueron muy abundantes y frecuentes, señalando la tendencia a baja diversidad. Los resultados más importantes permiten concluir que las condiciones agroecológicas de cada zona y el método de control empleado influyen en los parámetros fitosociológicos y diversidad de especies, determinando la composición y estructura de las comunidades de malezas asociadas al cultivo en el departamento del Magdalena.

ECONOMIC EFFICIENCY OF WEED CONTROL METHODS IN WINTER WHEAT CULTIVATION ON LARGE-SCALE FARMS

In modern agriculture, on large-scale farms using monoculture, reduced tillage and intense chemical protection, the phenomenon of herbicide resistance in weeds is the cause of ecological and economic losses. More and more attempts are made to answer the question about the profitability of reducing agrotechnical treatments and intensifying chemical methods of weed control with a simultaneous intensification of the problem of herbicide resistance in weeds occurring in winter wheat crops, which dominates the structure of cereal sowing in Poland. The main objective of the study was to evaluate the costs of weed control for winter wheat cultivation on large-scale farms where there was no problem of weed resistance and on farms where resistant biotypes were identified. The research was based on a survey conducted among owners of farms cultivating winter wheat in 2019. The collected data were elaborated using basic methods of descriptive statistics and economic analysis. Based on the research results, it was found that with an increase in the area of farms, reduced tillage and monoculture are used more frequently than conventional tillage and crop rotation. At the same time, the commonly used chemical weed control methods are more frequently applied than mechanical ones. Economic efficiency indicators for winter wheat protection against weeds indicate a decrease in this efficiency with an increase in farm size. This is because the larger the farms, the more frequently the occurrence of resistant weed biotypes, which was confirmed by laboratory tests, and farmers more often assumed that such a problem occurred on their farms

Analysis of the uniformity of the distribution of herbicides in the intercustal zone with a bar with a deviating section

It is known that a large share of the costs in perennial plantings of fruit and berry crops is associated with weed control. In the ranks of plants, chemical methods of weed control using herbicidal rods are used. In recent years, requirements for uniform distribution of herbicides on the treated surface have increased. The article analyzes the accuracy of the dosage of herbicides in the intercustal zone with a bar with a deviating section. The movement of the rod in the horizontal plane and the spill of liquid along its length is considered. The volume of the poured liquid, the area of the wetted surface, the amount of liquid per unit area are determined. It was established that the dose of application of herbicides over the area depends on the speed of the bar, the angle of its inclination to the direction of movement and the specific spill of the liquid along the length. It is shown that the more the rod deviates from its initial position and the closer it is to the row line, the greater the spout of the solution per unit area with respect to a given one. Dependencies are obtained that allow one to compare the doses of the application of the working solution of the herbicide on the treated surface before the bar meets the cultivated plant and when it is bypassed. The paper shows the data of calculation of the spill of the working fluid at a specific point of the rod. It was revealed that during the processing of the inter-brush strip in one pass with the half-line deviating section of the row line overlapping, the excess of the given outflow dose can reach 20 times. To process the inter-bush zones of perennial plantations, it is recommended to stack the herbicidal booms with short deflecting sections up to the row axis, providing compensation for inaccuracies in driving and planting trees in a row, and processing the row in two adjacent passes.

Cover crop diversity for weed suppression and crop yield in a corn–soybean production system in Tennessee

AbstractWeed communities may potentially reduce row‐crop yields resulting in a loss of revenue for producers. Studies have reported a decrease in the efficacy of chemical methods of weed control due to increased weed resistance. With the goal of reducing reliance on chemical weed control and promoting sustainable crop production in mind, we evaluated different winter cover crop (CC) types (single‐, double‐, and multi‐species) and CC planting methods (broadcasting vs. drilling) on CC and weed groundcover and row‐crop yield in a no‐till corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation system in Tennessee from 2013 to 2017. Our results showed that winter CC reduced spring weed ground coverage by 64–76% compared with winter fallow with no herbicide application. A five‐species CC mixture increased soybean yields by 6 to 8.5% across seeding method treatments compared with other CC treatments and winter fallow. This yield increase was more visible in a drought year. Corn, grown in years with normal weather patterns, did not show a yield response to CC types. From this study, cover cropping was found to be an effective strategy for weed control compared with leaving the field fallow without herbicide application following row‐crop harvest; however, no consistent species‐specific trends were observed on weed suppression and row‐crop yield. Future research should focus on understanding CC species composition and biomass production in double‐ and multi‐species mixtures from this field experiment to draw robust conclusions on agronomic responses of individual CC species and planting methods.

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.