Mechanical Weed Control Methods Research Articles

Design and experiment of an adaptive cruise weeding robot for paddy fields based on improved YOLOv5

Weed control in paddy fields is a critical agronomic practice for enhancing rice yield, in which mechanical weed control is widely used due to its high weed control rate and convenient operation. However, traditional mechanical weed control methods require manual operation, leading to increased operational costs. Therefore, adaptive cruise weeding robots hold significant application promise and market potential. In this paper, an adaptive cruise weeding robot for paddy fields based on improved YOLOv5 is designed to adaptively perform weeding operations. Firstly, a real-time rice seedling recognition method based on MW-YOLOv5s is proposed by establishing a rice seedling dataset under different paddy field environments and growth stages. The model combines the Backbone network structure with MobileViTv3, replacing GIoU_loss with WIoU_loss, which significantly improves the precision and speed of rice seedling recognition. Next, the MW-YOLOv5s was integrated into a paddy weeding machine, and seedling navigation lines were extracted using the least square method. Finally, the control system autonomously operates the weeding machine in real time through feedback control based on the navigation path. The test results showed that the MW-YOLOv5s model exhibits strong recognition performance for rice seedlings under different paddy field backgrounds and growth stages, with a precision of 90.05 % and an mAP of 92.32 %, while the real-time performance reaches 19.51 FPS, which meet the requirements for real-time operation of the weeding machine in paddy fields. The results of the paddy field weed control experiment reveal a weed control rate of 82.4 % and a seedling injury rate of 2.8 %, which meet the agronomic requirements for mechanical weed control in paddy fields. The research findings contribute to the design of intelligent agricultural equipment and promote the practice and application of machine vision in the field of paddy field plant protection.

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.

Performance Evaluation of Power Weeder with Different Blade Mechanism in Intra-row Weeding Operation

Aims: Weeding operation is one of the most laborious and time-consuming operation in agriculture. Weeds basically an unwanted plant which competes with crop for light, moisture, and nutrient along with lowering the overall yield. Mechanical weed control methods are preferred among all weeding methods due to many reasons such as timeliness, safety, drudgery and cost effective.
 Study Area and Duration: The experiment was conducted in the farmer’s field of Abhayapuri, Bongaigaon, Assam in the year 2021 to 2023.
 Methodology: This study employed a 5.75 hp self-propelled diesel engine with three blade sets—rotary, non-rotary, and a combination of both, designed for weeding in vegetable fields with row spacing up to 75 cm. One-way ANOVA analysis compared group means for statistical significance.
 Results: Results showed that the field efficiency (90%), fuel consumption (7.7 l/ha), cost of operation (Rs 1217.7 per ha) and plant damage factor (0.01%) was better for rotary blade than non-rotary and combined blade. Whereas effective field capacity (0.07 ha/h), performance index (155.7) and man-hour/ha (14.3) was better for non-rotary blade and the parameters such as depth (4.4 cm) and weeding efficiency (94.2%) was better for combined blade mechanism. From the one-way ANOVA analysis, it showed that blade mechanism showed significant difference on parameters like weeding efficiency, field efficiency, fuel consumption, effective field capacity, cost of operation, man-h/ha and performance index at p<0.05 and non-significant for depth and plant damage factor at P<0.05.
 Conclusion: Study concluded that for intra-row weeding operation, rotary blade along with non-rotary blade was suitable economically whereas combined blade was suitable for weeding performance only besides high cost.

Species composition of perennial weeds as influenced by mechanical steam treatment

Despite the great aspect of the use of chemical agents for plant protection against weeds, it is not always 100% commensurate with preparations. Since each plant develops immunity to drugs over a period of time, thus many agricultural producers strive to improve and find new methods of destroying parasites harming plants. Modern agricultural production reasonably puts forward the requirements for increasing the profitability and environmental safety of the products obtained. In this regard, there are great opportunities for the effective use of mechanical and physical methods of weed control, instead of problematic options for the use of herbicides. The improvement of tillage systems, in terms of greening agriculture, is primarily associated with their adaptation to a variety of soil and climatic conditions and in-depth differentiation in accordance with the agro-ecological requirements of crops. An optimally selected tillage system maintains a favorable phytosanitary condition of the soil for plants. Based on previous research in this area, the experience was studied and referred. The article presents the results of the number of treatments for the predominant weeds in the Southern Federal District of the Russian Federation. Taking into account early studies, it was revealed that due to the increased share of grain crops in the crop rotation, the amount of weed vegetation in the field increases over the years. We chose the chisel treatment method by the working bodies of the "Ranch" with a reservoir turnover of 0.12-0.15 m. When taking into account the clogging, the methods of A.M. Tulikov were used. There is a noticeable reduction in the contamination of certain plant species in all the years of the study for 2020-2022. Therefore, the goal was set to study each type of weed vegetation after cultivations prevailing in the Southern Federal District. The results were reliable and complete. By carrying out multiple cultivations, it was possible to identify weed vegetation most susceptible to processing by chisel organs of the "RANCH" without the introduction of chemical means of protection.

Weed Dynamics and Crop Productivity as Influenced by Weed Management Practices and Fertility Levels in Groundnut (Arachis hypogaea L.)

Background: Groundnut or peanut (Arachis hypogaea L.) is known as the “King of Oilseeds” which belongs to family Fabaceae (Leguminosae). It is highly susceptible to weed infestation because of its slow initial growth up to 40 DAS and small foliage cover. However, study on use of mechanical weed control methods with different fertility regimes for improving the productivity of groundnut was limited. Therefore, the objective of this study was to find a suitable method for optimising the productivity of groundnut. Methods: A field experiment was conducted at Odisha University of Agriculture and Technology, Bhubaneswar for two consecutive years of 2020 and 2021. The field experiment comprised 16 treatment combinations of four weed management practices and four fertility levels. The weed management practice included W1-Pre-emergence (PE) application of pendimethalin @ 0.75 kg ha-1, W2-Pre-emergence (PE) application of pretilachlor @ 0.5 kg ha-1, W3-Manual weeding (20 and 40 DAS), W4-Twin wheel hoe at 20 DAS followed by (fb) hand weeding at 40 DAS and four fertility levels includes T1-100% RDF (20:40:40) (N: P205: K2O kg ha-1), T2- 75% RDF + 5 tonnes FYM ha-1, T3- 50% RDF + 10 tonnes FYM ha-1, T4- without fertilizer + without FYM. Result: Amongst the weed management practices, use of twin wheel hoe at 20 DAS followed by hand weeding at 40 DAS significantly reduced the weed density, weed dry weight, weed index and recorded the highest weed control efficiency (69.8%). Highest weed index (32.9) was recorded with the application of pretilachlor @ 0.5 kg ha-1 (PE), which was followed by weed index of (28.5) with application of pendimethalin @ 0.75 kg ha-1 (PE). The fertilizer management practice with application of 50% RDF + 10 tonnes FYM ha-1 gave the highest yield and considerably reduced the total weed density, weed dry weight and recorded the maximum weed control efficiency (71.8 % at harvest). We suggest that weed management with twin wheel hoe at 20 DAS followed by hand weeding at 40 DAS along with application of 50% RDF + 10 tonnes FYM ha-1 as the most effective strategy for controlling the weed menace in groundnut with the highest weed control efficiency.

ECONOMIC ASPECTS OF MAIZE CULTIVATION TECHNOLOGIES IN THE TRANS-URALS REGION

Maise is a promising crop that stabilises crop production in the arid climatic conditions of the Trans-Urals region. To obtain maise feed in this region, especially given the short frost-free period, earlymaturing hybrids are cultivated, and technologies that allow for stable yields are used, typically intensive ones that involve active weed control (which is particularly relevant for row crops) and optimisation of the plant nutrition system. With the systematic increase in the prices of production inputs, primarily herbicides, mineral fertilisers, and fuel and lubricants, it is essential to consider the economic efficiency of technologies in specific conditions. This research aims to provide an economic assessment of various intensity levels of maise cultivation technologies in the Trans-Urals region under modern market conditions and establish economically efficient weed control methods. A comparison of productivity and economic indicators for extensive, regular, and intensive technologies was presented against three primary soil tillage methods: ploughing, minimal, and no primary (autumn) tillage. Comprehensive measures for protecting maise from weeds at different levels of soil tillage minimisation were shown. The economic efficiency of maise cultivation technologies was calculated at 2008 and 2022 prices. It was found that due to the faster rise in prices of chemical inputs compared to fuel and lubricant prices, the economic efficiency of mechanical weed control methods for maise is increasing. Despite a significant increase in fertiliser prices, their application under maise remains highly efficient, confirming the economic advantage of intensive technologies over extensive ones.

Soybean yield response to different mechanical weed control methods in organic agriculture in Luxembourg

Soybean (Glycine max (L.) Merr.) is very sensitive to interferences with weeds during vegetative growth. Weed control is a key factor for the successful production of soybean in organic agriculture. In Luxemburg, where soybean is not yet an established crop, cultivation trials were implemented to test and evaluate different methods of mechanical weed control in soybean cultivation. Trials were conducted in 2018 and 2019 at three locations in Luxembourg. A flex-tine harrow that can harrow the whole ground surface and a hoe used as inter-row cultivator were the basis of the mechanical treatments. Complementary technologies for the hoe such as the finger weeder, and an alternative method involving intercropping of soybean with camelina were also integrated in the trials. The main objective of the study was to evaluate the efficiency of the tested methods regarding weed regulation and their effects on soybean growth and development and grain yield. In comparison to the weed-free control, both hoeing and harrowing led to yields losses; these losses were lower with hoeing (- 2 %) than with harrowing (- 34 %). Yields were similar between hoeing and hand weeding and were also similar between harrowing and the weed-free control. The weed control index based on the difference in weed cover compared with the non-weeded treatment was above 0.6 for hoeing, about 0.2 for harrowing and lower than 0.01 for intercropping. Intercropping with camelina was not suitable for Luxembourg, especially during the dry study years of 2018 and 2019 due too poor establishment. Intra-row weeding with finger weeder in addition to inter-row hoeing did not significantly enhance the single use of the hoe in the inter-row. The non-selectivity of harrowing generated more soybean plant losses (- 28 %) and lower plant height (- 8 %) than hoeing (- 11 % and + 5 %, respectively) when compared with the weed-free control. Other yield components such as the number of pods per plant, number of beans per pod, thousand kernel mass, and the first pod height were not significantly affected by the weeding method. The efficiency of any treatment was low when weed infestation was already high after soybean emergence, although where weed infestation was low, any of the treatments were applicable. Encouraging rigorous weed management throughout the crop rotation is a key factor to maximize soybean yield.

Herbicide Resistance and Its Management Strategies - A Review

Due to their improved effectiveness and ability to save time, herbicides are the most widely used and effective weed control methods. However, prolonged use of herbicides brought about several issues, including environmental risks, shift weed in shift flora, and weed resistance. Herbicide resistance is one of the most significant issues worldwide today, out of all of these issues. The use of herbicides with extensive residual periods and a lack of rotation of the herbicide are the primary causes of herbicide resistance. Herbicide resistance is a global occurrence, and the number of resistant weed biotypes is alarmingly growing. In 252 plant species, there are already 480 occurrences of herbicide resistance. Weed herbicide resistance should be reduced since it is a significant barrier to food security. We could more effectively handle it if we thoroughly understood resistance development. Integrated weed management techniques, such as crop and herbicide rotations, herbicide combinations, and cultural, mechanical, and biological methods of weed control, can control the herbicide resistance problem

Herbicide Resistance and Its Management Strategies - A Review

Due to their improved effectiveness and ability to save time, herbicides are the most widely used and effective weed control methods. However, prolonged use of herbicides brought about several issues, including environmental risks, shift weed in shift flora, and weed resistance. Herbicide resistance is one of the most significant issues worldwide today, out of all of these issues. The use of herbicides with extensive residual periods and a lack of rotation of the herbicide are the primary causes of herbicide resistance. Herbicide resistance is a global occurrence, and the number of resistant weed biotypes is alarmingly growing. In 252 plant species, there are already 480 occurrences of herbicide resistance. Weed herbicide resistance should be reduced since it is a significant barrier to food security. We could more effectively handle it if we thoroughly understood resistance development. Integrated weed management techniques, such as crop and herbicide rotations, herbicide combinations, and cultural, mechanical, and biological methods of weed control, can control the herbicide resistance problem.

Response of Rice (Oryza sativa L.) to Weed Management Methods in the Lower Gangetic Plain Zone

Background: In India, rice covers largest area under cultivation. Among the biotic stresses weeds pose serious threat to rice if not controlled in its critical crop-weed competition period, reducing yield by 50%, in case of transplanted rice. The experiment was carried out to evaluate effectiveness of different herbicides and its combination with mechanical weed control methods in checking weed population in transplanted rice so as to maintain sustained production. Methods: The experiment was carried out in lower Gangetic plain zone during kharif season of 2018. It was laid out in randomized block design with seven treatments replicated thrice. The treatments were pretilachlor 50% EC@ 1500 ml ha-1 (0-4 DAT), butachlor 50% EC @ 4000 ml ha-1 (0-4 DAT), bispyribac Na 10% SC @ 200 ml ha-1 (Post-emergence), Sesbania intercrop @ 25 kg ha-1 up to 30 DAT followed by mechanical incorporation followed by 1 hand weeding @ 50 DAT, pretilachlor 50% EC @ 1500 ml ha-1 (0-4 DAT) followed by bispyribac Na 10% SC @ 2000 ml ha-1 (25 DAT), two hand weedings at 25 DAT and 50 DAT and untreated control. Result: Cyperus rotundus, Cyperus difformis, Alternanthera philoxeroides, Ludwigia octovalvis, Echinochloa colona, Fimbristyslis sp. were the dominating weed species as per experimental findings. Among all treatments two hand weedings at 25 DAT and 50 DAT significantly reduced the total weed density (no.m-2) while total weed biomass (g m-2) as was found to be lowest in treatment of pretilachlor 50% EC @ 1500 ml ha-1 (0-4 DAT) followed by bispyribac Na 10% SC @ 2000 ml ha-1 (25 DAT). Highest growth characteristics in rice was observed in treatment of two hand weedings at 25 DAT and 50 DAT. Pre- emergence and post-emergence application of pretilachlor and bispyribac sodium, respectively, was successful in achieving highest yield attributes, yield (4.12 t ha-1) and economic return (Rs. 47438 ha-1).

Weeding of safflower crops under the influence of agricultural treatments on non-herbicide and herbicide background

Weeds are a big problem with safflower crops. To control weeds, it is necessary to develop an effective system of herbicide use and mechanical methods of weed control for arid conditions of the Southern steppe of Ukraine. In weed–infested fields, the protein content of cereals decreases and that of oilseeds in oil fields. Weed reduction reduces the productivity of agricultural machinery and implements, increases production costs. Weeds reduce the effectiveness of fertilizers, irrigation and other measures aimed at increasing crop yields. The article presents the main results of research for 2017–2019 to study the impact of agricultural practices for the care of safflower crops on herbicide and herbicide–free backgrounds on the weediness of safflower crops. The research was conducted in the fields of the Institute of Oilseeds of NAAS. The system of the main tillage: classical. Variants of the crop care system: 1 – without care (control); 2 – harrowing before and after germination; 3 – 2 row spacing; 4 – harrowing and inter–row cultivation. Application of soil herbicide led to a decrease in the total number of weeds before harvesting in crops of safflower variety Zhyvchyk by 9,3–16,0 and in crops of variety Dobrynya by 8,3–17,7 pieces/m2. The number of weeds before harvesting was the lowest in the variants with two inter–row treatments and was equal to: 16,0 pieces/m2 – on a background with out herbicide and 6,7 pieces/m2–on a herbicide background in crops of Zhyvchyk variety; 14,3 and 6,0 pieces/m2, respectively, in crops of Dobrynya variety. The lowest values of air–dry mass of weeds before harvesting: 81,5 and 39,6 g/m2 in crops of Zhyvchyk variety and 84,3 and 36,9 g/m2 were obtained in the variant with two inter–row treatments. The highest yields were provided by growing safflower varieties using post–emergence harrowing + inter–row cultivation: on a herbicide–free background – 1,35 t/ha in the variety Zhyvchykand 1,40 t/ha in the variety Dobrynya, on a herbicide background 1,54 and 1,64 t/ha, respectively. Key words: safflower, variety, agricultural production, herbicide, weed, yield.

Soybean Yield Response to Different Mechanical Weed Control Methods in Organic Agriculture in Luxembourg

Soybean Yield Response to Different Mechanical Weed Control Methods in Organic Agriculture in Luxembourg

Residual effect of organic weed and organic nutrient management practices on weeds parameters, growth attributes, yield and economics of Indian mustard (Brassica juncea L.)

The organic nutrient and weed management practices applied in maize and their residual efficiency was seen in succeeding mustard crop in respect of weed management and productivity of mustard. Therefore, an experiment was conducted during rabi 2019- 20 and 2020-21 at College of Agriculture, Sumerpur, Rajasthan, India to see the residual impact of various weed and nutrient management practices on mustard applied in maize during preceding kharif season. The experiment was laid out in a split-plot design, with organic weed management in main plots and organic nutrient management practices in subplots. The crop was raised as residual after main crop of maize. All the treatments were applied in maize during kharif season as per prescribed treatments. The different organic weed and nutrient management treatments did not influence the weed density and weed dry matter of various categories of weeds recorded at 30 DAS. The plant height, dry matter accumulation, number of primary branches and length of silique of mustard was maximum in 100% RDN through FYM in pooled study at different growth stages of crop. This treatment also significantly increased grain (2174 kg/ha) and straw yield (5858 kg/ha) of mustard as well as net return (Rs. 68575/ha) and B:C (2.91) as against the mean minimum in 100% RDN through vermicompost. Thus, application of FYM in preceding season crop has a pronounced effect on productivity of succeeding crop while cultural and mechanical methods of weed control does not have any residual effect.

Efficacy of Various Mechanical Weeding Methods—Single and in Combination—In Terms of Different Field Conditions and Weed Densities

Public awareness and environmental policies have increased interest in applying non-herbicide weed control methods in conventional farming systems. Even though mechanical weed control has been used for centuries in agricultural practice, continuous developments—both in terms of implements and automation technologies—are continuously improving the potential outcomes. Current mechanical weed control methods were evaluated for their weed control efficacy and effects on yield potential against their equivalent herbicide methods. Furthermore, not much is known about the correlation between weed control efficacy (WCE) of different mechanical methods at varying weed density levels. A total of six experiments in winter wheat (2), peas (2), and soybean (2) were carried out in the years 2018, 2019, and 2020 in southwestern Germany. Harrowing and hoeing treatments at different speeds were carried out and compared to the herbicide treatments and untreated control plots. Regarding the average WCE, the combination of harrowing and hoeing was both the strongest (82%) and the most stable (74–100%) mechanical treatment in the different weed density levels. Whereas, in average, hoeing (72%) and harrowing (71%) were on the same WCE level, but harrowing (49–82%) was more stable than hoeing (40–99%). The grain yields in winter wheat varied between 4.1 Mg∙ha−1 (control) and 6.3 Mg∙ha−1 (harrow), in pea between 2.8 Mg∙ha−1 (hoe slow) and 5.7 Mg∙ha−1 (hoe fast) and in soybean between 1.7 Mg∙ha−1 (control) and 4 Mg∙ha−1 (herbicide). However, there were no significant differences in most cases. The results have shown that it is not possible to pinpoint a specific type of treatment as the most appropriate method for this cultivation, across all of the different circumstances. Different field and weather conditions can heavily affect and impact the expected outcome, giving, each time, an advantage for a specific type of treatment.

Influence of Mechanical and Intelligent Robotic Weed Control Methods on Energy Efficiency and Environment in Organic Sugar Beet Production

Rapidly warming climate, tightening environmental requirements, an aging society, rising wages, and demand for organic products are forcing farming to be more efficient and sustainable. The main aim of this study was to perform an analytical analysis and to determine the energy use and GHG emissions of organic sugar beet production using different weed control methods. Seven different methods of non-chemical weed control were compared. Mechanical inter-row loosening, inter-row cutting and mulching with weeds, weed smothering with catch crops, and thermal inter-row steaming were performed in field experiments at the Experimental Station of Vytautas Magnus University (Lithuania, 2015–2017). The other three, namely, automated mechanical inter-row loosening with cameras for row-tracking, inter-row loosening with a diesel-powered robot, and inter-row loosening with an electric robot were calculated analytically. The results showed that the average total energy use of organic sugar beet production was 27,844 MJ ha−1, of which manure costs accounted for 48–53% and diesel fuel for 29–35%. An average energy efficiency ratio was 7.18, while energy productivity was 1.83 kg MJ ha−1. Analysis of GHG emissions showed that the total average GHG emissions to the environment from organic sugar beet production amounted to 4552 kg CO2eq ha−1, and the average GHG emissions ratio was 4.47. The most sustainable organic sugar beet production was achieved by using mechanical inter-row loosening with a diesel-powered robot for weed control.

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.

Promising directions for the creation and use of technical means for weed control in the system of organic farming

Annotation Purpose. Reduction of labor costs for the production of organic vegetable products through the creation and use of new methods and techniques for weed control. Methods. Monographic, analytical, abstract-logical, structural modeling, design and manufacture of alternative technical means for the implementation of effective methods of weed control in the system of organic farming. Results. The main alternative methods and technical means for weed control in the system of organic farming in the world and in Ukraine are identified. Currently, alternative methods of weed control are weed control by flame, hot water and steam, and electropulse weed control. In fire cultivation, when the soil heating temperature does not exceed 70 °C, proteins in weed plants are damaged in the “thread” stage. In phase 4–6 the leaves, at the same temperature, destroy up to 90 %, and in the later phase of development – up to 75 % of weeds. Conclusions. An analysis of research and publications has shown that the use of known mechanical, thermal and electropulse weed control methods in various technological operations for growing crops will allow effective weed control in organic farming without the use of chemicals. The high-precision navigation system developed in the NSC “IAEE”, which is capable of carrying out a machine-tractor unit at a predetermined trajectory with a deviation of ±2 cm, will solve the problem of combating weeds in the ranks of vegetables and ingun crops in the system of organic farming. Keywords: organic farming, fire cultivation, weed control, steam and hot water, electropulse action.

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.

Impact of different mechanical weed control methods on weed communities in organic soybean cultivation in Luxembourg

Knowledge gaps have been identified for legumes cultivation in Luxembourg, especially in terms of weed control, where soybean production is still at its initial stages. The study tests different mechanical weed control methods in organic soybean cultivation on-farm. The impacts of different weeding techniques are observed from an ecological point of view, in terms of species number and diversity. The cultivation trials, one-factorial exact trials with four replicates, were conducted on two organic farms in 2018 and 2019. Five different treatments were tested: harrow, interrow cultivator with duck foot shares, interrow cultivator and finger weeder, combination of harrow, interrow cultivator and finger weeder and an intercropping soybean-camelina combined with harrow. For each, the number of weed species, as well as their identification, has been assessed three times: before weed control, after weed control and at the flowering of soybean. Calculated Shannon indexes have quantified the diversity of weeds. Forty-nine weed species have been counted in total, for all sites. Calculated Shannon indexes were common values for organic fields. Weed control has a negative impact on weed diversity. Low abundant species were more likely to disappear, while few species, one to four, keep being more dominant. The use of the interrow cultivator, in combination with the harrow (as blind harrowing) and the finger weeder, tends to lower the most the number of species and the diversity of weeds. Further ecological research is necessary to better determine the interactions between weeds and soybean.

Editorial - Crop health in agroforestry systems: An introduction to the special issue

Weeds are a serious threat to crop production in Iran as they reduce the yield of wheat, barley, rice, maize, and chickpea on average by 23%, 21%, 35%, 20%, and 50%, respectively. Orobanche spp., Avena ludoviciana (Durieu.), Convolvulus arvensis (L.), Sorghum halpence (L.) Pers, and Cuscuta compestris (Y.) are the most important weed species that compete with major crops in Iran. Recently, some newly introduced and invasive weeds, including Hordeum spontaneum (K. Koch.), Cynanchum acutum (L.), Physalis divaricata (L.), and Azolla filiculoides (Lam.), have become a very serious problem in a wide range of crops in different parts of Iran. Chemical control is the predominant weed management practice in Iran. In addition, mechanical weed control methods including soil tillage and hand weeding are applied to a lesser extent. 2,4-D + MCPA (in cereal crops), clodinafop-propargyl (in wheat crop), haloxyfop-r-methyl ester (in broadleaved crops), tribenuron-methyl (in wheat), nicosulfuron (in maize), trifluralin (in oil crops), metribuzin (in potato), glyphosate (in orchards and non-cultivated areas), and paraquat (in waste lands and between crop rows) are the most commonly used herbicides in Iran. There are currently 14 unique cases (species x site of action) of herbicide-resistant weeds in Iran. The most important and newly emerged challenges in Iran are to manage the present noxious and invasive weed species. Increasingly, the evolution of herbicide-resistant biotypes in wheat and other important crops would be another challenge in the future. In addition, the adoption and extension of integrated weed management strategy, addition of suitable adjuvants to herbicide tank mixture, and use of proper sprayers would remain critical challenges in weed management practices in Iran. The integration of weed control methods such as crop rotation, tillage, planting date and pattern, herbicides, and allelopathy would lead to the effective and sustainable management of weeds.