Weed Management Methods Research Articles

Degradation Pattern and Residues of Atrazine in Maize under Long Term Conservation Agriculture

Field experiment was conducted at Eastern block farm, Tamil Nadu Agricultural University 11°29”N latitude and 77° 08”E longitude with an altitude of 426.7M above MSL with maize to study the degradation, persistence and residues of atrazine under long term conservation agriculture system. The treatments constituted atrazine 1.0 kg ha-1 on 3 DAS and atrazine 1.0 kg ha-1 on 3DAS +Hand weeding on 45th day under different conservation tillage practices. Degradation, persistence and residue analysis were carried out for atrazine using HPLC. Residues of atrazine was analyzed at different periods viz., 0,15,30,45,60,75 and 90 days after herbicide application and at harvest and the results revealed that degradation of atrazine was found to follow first order reaction kinetics (R2> 0.94) with the half life of 13.7–16.2 days irrespective of tillage practices and weed management methods. The recommended rate of atrazine @1.0 kgha-1 recorded terminal residues below detectable limit of <0.01 mg kg-1 in soil and plant parts of maize.

Impact of Live Mulch, Brown Manuring and Herbicides on Growth and Yield of Sorghum (Sorghum bicolor (L.) Moench) in Southern Midland Zone of Kerala, India

A field experiment was conducted during the rabi season of 2023 at the Farming System Research Station, Sadanandapuram, Kerala, to evaluate the effects of live mulch, brown manuring and herbicides effect as weed management method on growth and yield of sorghum. The experiment was conducted in a randomized block design with ten treatments, replicated thrice. The treatments included: Broadcasting cowpea seeds @ 15 kg ha -1 fb live mulch at 25 DAS, Broadcasting cowpea seeds @ 30 kg ha -1 fb live mulch at 25 DAS, Broadcasting cowpea seeds @ 15 kg ha -1 fb brown manuring with 2,4-D 1 kg ha-1 at 20 DAS, Broadcasting cowpea seeds @ 30 kg ha -1 fb brown manuring with 2,4-D 1 kg ha-1 at 20 DAS, PE pretilachlor 0.75 kg ha-1fb one HW at 25 DAS, fenoxaprop-p-ethyl 0.06 kg ha-1 at 20 DAS, T7:PoE 2,4-D 1 kg ha-1 at 20 DAS, HW at 20 DAS, Weed free control and Weedy check. Among the treatments, broadcasting cowpea seeds at 30 kg ha⁻¹ followed by live mulch at 25 DAS (T2) resulted the higher growth parameters, including plant height, number of leaves per plant, and dry matter production at 45 DAS and harvest. Leaf area per plant and leaf area index were also significantly higher in T2 at 30 and 45 DAS. Yield attributes, such as panicle length, number of grains per panicle, grain weight per panicle, grain yield, stover yield and harvest index were higher in T2. Broadcasting cowpea seeds @ 30 kg ha -1fb brown manuring with 2,4-D 1 kg ha-1 at 20 DAS, pre-emergence pretilachlor 0.75 kg ha⁻¹ fb hand weeding at 25 DAS, post-emergence fenoxaprop-p-ethyl 0.06 kg ha⁻¹ at 20 DAS and weed free control performed statistically comparable with T2 in terms of growth and yield attributes.

Effective weed control through post-emergence herbicides to enhance blackgram (Vigna mungo L.) productivity in South India

Pulses are essential components of vegetarian diet and play a pivotal role in addressing malnutrition by providing a vital source of dietary protein. However, weed competition remains as a significant obstacle to blackgram (Vigna mungo L) production, resulting in 25 to 35% yield losses. A field experiment was carried out at the National Pulses Research Centre, Tamil Nadu Agricultural University, Vamban, Pudukkottai, India during Kharif seasons of 2020 and 2021, to assess the suitable post-emergence herbicides for appropriate weed control in blackgram grown under irrigated conditions. The experimental field was observed to contain notable grass weed flora, specifically Dactyloctenium aegyptium and Chloris barbata, as well as broadleaved weeds, such as Flaveria australica, Cleome gynandra, Eclipta alba, Convolvulus arvensis, Digera arvensis, Vicia spp., and Celosia argentea. The results demonstrated that among the chemical weed management methods, spraying of Fomesafen @ 220 g + Fluzifop p-butyl @ 220 g ha−1 at 20 days after sowing (DAS) as a post-emergence herbicide treatment exhibited superior weed control efficiency, recording 66.80% and 68.53% at 30 and 45 DAS, respectively and recorded higher seed yield of 1088 kg ha−1. Additionally, this method generated 8.1% higher net income and 12.5% more benefit–cost ratio than hand weeding, making it an economically profitable strategy for maximizing blackgram yield and effective labour management.

Herbicide Combinations for Effective Weed Management in Rice

Rice (Oryza sativa L.) is the most important food crop catering half of the world’s population. India being the second largest producer of rice, needs to produce around 120 million tons of rice by 2030 to feed its one and a half billion plus population. Weeds are undoubtedly a major biotic constraint to rice production in most of the rice growing areas of the world. Rice fields are very often characterized by a complex plurispecific weed flora, comprising of grasses, sedges, and broad-leaved weeds (BLWs). They usually grow faster than rice and absorb available water and nutrient earlier than the rice and suppress rice growth. Cultural and mechanical methods of weed management in general, are time consuming, cumbersome and laborious apart from being less effective because of chance of escape and regeneration of weeds from roots or rhizome that are left behind. Herbicides offer the most effective, economical and practical way of weed management. Since rice ecosystems usually harbours a variety of weeds, the use of a single herbicide cannot give satisfactory results. Moreover, continous use of such herbicides leads to the evolution of weeds resistant to several herbicides. Therefore, more convenient option would be single shot application of ready mix or tank mix combination of herbicide. The herbicide mixtures broaden the spectrum of weed control in single application. The ideal herbicide combinations are those that effectively target the weed species while minimizing toxicity to crops, thereby exhibiting enhanced selectivity. Using herbicide combinations allows for reduced herbicide use rates compared to using a single herbicide. Additionally, apart from providing broad-spectrum weed control, herbicide combinations reduce the herbicide load in the environment and minimize application costs. Among the various combination herbicides available, the ones having pre-emergence and post-emergence herbicides combined had shown better weed control with single shot application at reduced cost. Some of the ready-mix herbicide combinations that are gaining greater importance includes Pretilachlor + Pyrazosulfuron-ethyl, Pendimethalin + Penoxsulam and Butachlor + Penoxsulam.

Selection and adaptation to weed management methods: implications for non-chemical and integrated weed management approaches.

Herbicide-resistant weeds are a growing global concern, threatening food security. Non-chemical weed management approaches are becoming increasingly important. Furthermore, the adoption of non-conventional agricultural practices is on the rise, with regenerative farming practices aimed at rebuilding soil organic matter, restoring biodiversity, and reducing chemical use gaining traction. Consequently, non-chemical weed management methods are seen as essential solutions. However, excessive reliance on these methods may inadvertently lead to weed selection and adaptation, reducing their effectiveness. Here, we explore the mechanisms driving changes in efficacy due to selectivity and adaptation to non-chemical weed management practices. Additionally, we discuss potential integrated weed management (IWM) strategies that combine chemical and non-chemical methods to mitigate the risks of weed adaptation. This study highlights the role of evolutionary processes in shaping weed adaptation to non-chemical weed management methods and underscores the need to understand these processes to develop IWM approaches that remain effective over time. Monitoring phenological shifts and adaptations in the field should be a key component of decision support systems, tailored to the unique conditions of each site. Furthermore, a deeper understanding of weed adaptation mechanisms can enhance the efficacy of IWM strategies and help delay the inevitable adaptation to these control methods. © 2024 Society of Chemical Industry.

Battery-Operated Power Weeding Machines: Advancements, Challenges, and Future Prospects

In recent years, significant advancements have been made in the development and adoption of battery-operated power weeding machines, offering a sustainable and efficient alternative to traditional weed management methods. Previous studies have highlighted several critical benefits of these machines, particularly in reducing labor costs and minimizing environmental impact. Battery-powered weeders have been shown to significantly cut down on manual labor requirements, thus reducing the physical strain on farmers and decreasing the reliance on hired labor. This reduction in operational costs makes them an economically viable option for small and medium-sized farms. Furthermore, the environmental advantages of these machines are notable. Unlike chemical herbicides, which pose risks of soil and water contamination and potential health hazards, battery-operated weeders offer a clean alternative, eliminating the need for harmful chemicals. This aligns with the growing demand for environmentally sustainable agricultural practices. Technological advancements have further enhanced the efficiency and usability of these machines. Modern battery-powered weeders are increasingly equipped with lithium-ion batteries that provide longer operation times, precision sensors for accurate weed targeting, and automated control systems that simplify operation. These innovations have not only improved the effectiveness of weed management but have also made these machines more accessible and user-friendly for farmers. Field trials and studies conducted in various agricultural settings have consistently demonstrated the practicality and reliability of battery-operated weeders, making them a transformative solution in modern agriculture. The integration of these machines into farming practices has been shown to improve productivity, reduce costs, and promote sustainability, solidifying their role as a critical innovation in the future of agriculture. This review article aims to build upon these findings by providing a detailed examination of the design, development, and performance of battery-operated weeding machines, and exploring their broader applications in diverse agricultural environments.

Residual Effect of Nitrogen and Weed Management Practices in Maize on Succeeding Groundnut

Background: Cereal-legume cropping system is considered to be one of the better alternatives for sustaining soil fertility and increasing the yield. At present maize-groundnut cropping system is gaining importance under both rainfed and irrigated situations. Maize, being an exhaustive and weed-sensitive crop, is supplied with large doses of fertilizers and new herbicide molecules.Since maize is exhaustive and weed sensitive crop, there was a usage of excessive fertilizers and new herbicides. There is a need to assess the carry over effect of fertilizers and new generation herbicides in leguminous crops like groundnut. Methods: The experiment was conducted during two consecutive rabi seasons of 2019-20 and 2020-21 on sandy loam soils of S.V. Agricultural College, Tirupati andhra Pradesh. Maize hybrid DHM -117 was sown and maintained with general cultivation practices except for nitrogen and weed management methods was raised after harvest of maize in undisturbed layout to study the residual effect of different nitrogen and weed management practices imposed in maize. Result: Residual effect of nitrogen and weed management practices imposed in preceding maize did not exert any significant influence on germination percentage, phytotoxicity and SPAD chlorophyll meter reading (SCMR) values but efficacy of herbicide residue found to be significant with weed management practices. Growth parameters, yield attributes pod yield, haulm yield and economics were higher in groundnut with brown manuring, which was however, in parity with hand weeding twice at 15 and 30 DAS, pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of topramezone 30 g ha-1 and pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of tembotrione 120 g ha-1 and lower with unweeded check and it was remained in parity with application of parthenium water extract15 lha-1 twice at 15 and 30 DAS, application of sunflower water extract 15 lha-1 twice at 15 and 30 DAS, pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of parthenium water extract 15 lha-1 and pre emergence application of atrazine 1.0 kg ha-1 fb post emergence application of sunflower water extract 15 lha-1 in the order of ascent. None of their interaction effects were found to be significant during both the years of study and in pooled mean.

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.

Allelopathic Activity of Three Wild Mediterranean Asteraceae: Silybum marianum, Cynara cardunculus var. sylvestris, Galactites tomentosus

The manipulation of allelopathic mechanisms, such as the isolation of plant allelochemicals for bioherbicide production, is currently providing a new tool for weed management methods of reducing or potentially eliminating the use of synthetic herbicides. In Mediterranean agroecosystems, wild Asteraceae are the prevalent taxa, likely due to their allelopathic activity. Hence, the objective of this study was to evaluate the allelopathic effects of the aqueous extracts obtained from milk thistle [Silybum marianum (L.) Gaertn], wild cardoon (Cynara cardunculus L. var. sylvestris) and purple milk thistle (Galactites tomentosus Moench) on the seed germination, mean germination time, and seedling growth of three target weeds: Portulaca oleracea L., Taraxacum officinale (Weber) ex Wiggers and Anagallis arvensis L. The total polyphenol (TP), flavonoid (TF), flavonol (TFL), and phenolic acid (TPA) content in the aqueous extracts was also evaluated. Overall, the allelopathic effects were species-dependent and root length was the most affected parameter. All extracts completely inhibited root development in P. oleracea. Averaged over target weeds, C. cardunculus extract had the greatest allelopathic activity, followed by G. tomentosus and by S. marianum. In particular, C. cardunculus reduced seed germination by over 50% and increased the mean germination time by 154%, likely due to the highest TP (13.2 g kg−1 DM) and TPA (11.4 g kg−1 DM) content, compared to the other Asteraceae species. These results provide evidence of the phytotoxic activity of the three wild Asteraceae members and suggest their possible future exploitation as potential bioherbicides for sustainable weed management.

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.

Evaluation of Weed Management Practices in Maize (<i>Zea mays</i>) at Metu, Ethiopia

A field experiment was conducted at Metu Agricultural sub – centre on station in 2015 and 2016 cropping seasons to evaluate the effectiveness and economic feasibility of weed management methods on maize grain yield at Metu area. BH 661 at 25 kg/ha used as seed source. The experiment comprised of nine treatments laid out in randomized complete block design (RCBD) with three replications. The result revealed that the highest average grain yield 62.8 q/ha was obtained from Integrity EC 668g/l 1.0 liter with two supplementary hand weeding followed by 61.6 q/ha from Integrity EC 668g/l 1 liter with one hand weeding. Similarly, the minimum above ground wee dry biomass mean 0.07q/ha, 1.5 q/ha obtained from three hand weeding at 30, 60 and 90 days after planting and Integrity EC 668g/l 1.0 liter with two supplementary hand weeding respectively. Consequently highest weed control efficiency 99.93% and 98.5%obtained from the same treatment. In economic feasibility aspect the highest net benefit Accordingly the highest net benefit 61296.4 ETB ha<sup>-1 </sup>was obtained from Integrity EC 668g/l at 1.0 L/ha + two time supplementary hand weeding with 3042.86 MRR% followed by 60146.2 ETB ha<sup>-1 </sup>net benefit with 5661.90% MRR obtained from Integrity EC 668g/l at 1 l/ha + one times supplementary hand weeding whereas the minimum net benefit 50551.2 ETB ha<sup>-1</sup> and 53224.2 ETB ha<sup>-1</sup> obtained from one hand weeding at 30 & 454 days after planting respectively. Therefore, Integrity EC 668g/l at 1 l/ha + two times supplementary hand weeding and Integrity EC 668g/l at 1 l/ha + one time supplementary hand weeding treatment consecutively more profitable weed management practices to control weeds in maize and there by improve crop production up to 56.94% than other treatments and can be recommended for maize production at Metu area.

Dissipation Kinetics, Leaching, and Ecological Risk Assessment of S-Metolachlor and Benfluralin Residues in Soil

The use of selective herbicides is one of the best methods for weed management. However, the extensive use of herbicides can have adverse impacts on non-target organisms. The goals of this study were to assess the dissipation kinetics, leaching, and ecological risk assessment of S-metolachlor and benfluralin residues in silty loam soil planted with chickpea (Cicer arietinum L.). The experimental setup included four different layers with four replications corresponding to an experimental randomized complete block design consisting of 16 plots. The application doses of S-metolachlor and benfluralin were 1350 and 1920 g a.i./ha, respectively, according to manufacturer recommendations. Soil samples were split into four depths, 0 to 20 cm (Layer A), 20 to 40 cm (Layer B), 40 to 60 cm (Layer C), and 60 to 80 cm (Layer D), to determine the dissipation kinetics and the leaching behavior of the herbicides. Gas chromatography coupled with the electron capture detector (GC-ECD) method was developed and validated for the determination of S-metolachlor and benfluralin residues in soil. The analytes were extracted from the soil with distilled water and ethyl acetate followed by solid-phase extraction (SPE). The limit of quantification (LOQ) of the method was 0.1 μg/g, and the recoveries of S-metolachlor and benfluralin were in the ranges 81% to 97% and 88% to 101%, respectively, with relative standard deviations (RSD) of less than 9.7%. The dissipation kinetics of S-metolachlor and benfluralin in soil (0–20 cm) followed first-order kinetics with half-lives of 21.66 and 30.13 days, respectively. The results for samples obtained from the 20–80 cm soil profile showed that both benfluralin and S-metolachlor presented high leaching, following preferential flow. Also, a soil ecological risk assessment was conducted in the top 0–20 cm soil profile, estimating the toxicity–exposure ratio (TER) for four soil organisms and the risk quotient (RQ). The mean herbicide levels found at the studied soil profile at 0 days (2 h) and 60 days of the experiment were used for risk assessment. In the first case, the mean pesticide concentration (MPC) gives a worst-case scenario (ws); in the second case, a dissipation scenario (ds) is given using the respective MPC. In all cases, both TER and RQ values showed that benfluralin corresponds to a higher risk than S-metolachlor for soil organisms.

Performance of Post-Emergence Herbicide Combinations on Weed Management and Crop Yield in Direct Seeded Rice (Oryza sativa L.)

Direct-seeded rice (DSR), an innovative alternative to traditional transplanting, has gained popularity for its cost-effectiveness and labour-saving attributes. Weeds pose a significant threat to DSR. In this study, the effectiveness of various weed management methods, including hand weeding and herbicide applications, was evaluated. Hand weeding proved most effective in controlling weeds, while specific herbicides, such as bispyribac sodium + pyrazosulfuron (T2) and triafamone + ethoxysulfuron (T6) applied at 16 days after sowing (DAS), demonstrated superior weed control efficiency, improved growth parameters, and enhanced yield. Paspalum distichum was effectively controlled by penoxsulam + cyhalofop-butyl (T7). The study emphasizes the importance of customizing weed control to local conditions, with the choice of suitable herbicides and practices aligning with prevalent weed biotypes in the specific farming system. Understanding the nuanced impacts of post-emergence herbicides is crucial in navigating the intricate landscape of weed management in direct-seeded rice.

Weed Detection

Effective weed detection and management are crucial for ensuring optimal crop growth and yield in agricultural fields, particularly in wheat crops where weed competition can significantly impact productivity. Traditional weed management methods, such as manual scouting, mechanical weeders, and chemical herbicides, have limitations in terms of accuracy, efficiency, and environmental sustainability. To address these challenges, this study proposes a novel weed detection and management system based on deep learning and computer vision techniques. The system leverages advanced convolutional neural networks (CNNs), including YOLOv3 and YOLOv5, to detect and classify weeds in real-time from images captured in wheat fields. By analyzing a diverse range of research papers and methodologies in the field, a comprehensive literature review was conducted to identify key trends, challenges, and opportunities. Feasibility studies were conducted to assess the technical, operational, economic, legal, and functional aspects of the proposed system, demonstrating its potential for successful implementation and adoption across diverse agricultural settings. The system offers several advantages, including high accuracy weed identification, real-time monitoring, targeted herbicide application, and scalability for large-scale agricultural operations. Additionally, the system promotes environmental sustainability by minimizing herbicide usage and preserving soil health. Overall, the proposed weed detection and management system represents a significant advancement in agricultural technology, offering a sustainable, efficient, and scalable solution for addressing the challenges of weed control in wheat crops.

Effect of weed management methods on weeds in the crop of maize (Zea mays L.).

Effect of weed management methods on weeds in the crop of maize (Zea mays L.).

Integrated Weed Management in Minor Millets: A Review

Presently, agriculture is facing tremendous problem due to climate change and global warming. To ensure food and nutritional security at national level, there is an immediate need to promote the cultivation of millets as millets are considered climate smart and nature friendly crops because of high nutritive value and can withstand under warm and drought conditions with short life, low external inputs requirement, tolerance to water and temperatures stress. Ten millet crops have been declared as ‘Nutri Cereals’ which include three major millets i.e., pearl millet, sorghum and finger millet; five minor millets i.e. foxtail millet, proso millet, kodo millet, barnyard millet, little millet; and two pseudo millets i.e. kuttu (buckwheat) and amaranthus. Due to sluggish growth in initial phases of life, millets proved relatively poor competitors against weeds. Manual weeding is the most commonly adopted for weed control in millets. But the non-availability of labour and ever-increasing labour wages have compelled the farmers to seek alternate method of weed management. Herbicide use is the most viable method of weed control but their continuous and excessive use is not advisable due to its ill effects on environment and development of herbicide resistance in weeds. Very limited options are available in literature for weed control in minor millets. Thus, integrated weed management practices should be followed on site and time specific basis for effective and efficient weed management in minor millets. For integrated weed management in minor millets, 2-3 times inter-cultivation and 1-2 time hand weeding during initial 25 days after sowing in addition to pre-emergence spray with Isoproturon @ 0.5 -1.0 kg a.i./ha and post emergence spray of 2, 4-D sodium salt @ 0.75-1.0 kg a.i./ha at 20-25 days after sowing should be done for effective weed control.

Non-targeted effects of nitrification inhibitors on soil free-living nitrogen fixation modified with weed management

Biological nitrogen fixation and nitrification inhibitor applications contribute to improving soil nitrogen (N) availability, however, free-living N fixation affected by nitrification inhibitors has not been effectively evaluated in soils under different weed management methods. In this study, the effects of the nitrification inhibitors dicyandiamide (DCD) and 3, 4-dimethylpyrazole phosphate (DMPP) on the nitrogenase, nifH gene，and diazotrophic communities in soils under different weed management methods (AMB, weeds growth without mowing or glyphosate spraying; GS, glyphosate spraying; MSG, mowing and removing weeds and glyphosate spraying; and WM, mowing aboveground weeds) were investigated. Compared to the control counterparts, the DCD application decreased soil nitrogenase activity and nifH gene abundance by 4.5 % and 37.9 %, respectively, under the GS management method, and the DMPP application reduced soil nitrogenase activity by 20.4 % and reduced the nifH gene abundance by 83.4 % under the MSG management method. The application of nitrification inhibitors significantly elevated soil NH4+-N contents but decreased NO3−-N contents, which had adverse impacts on soil nifH gene abundance and nitrogenase activity. The nifH gene abundances were also negatively impacted by dissolved organic N and Geobacter but were positively affected by available phosphorus and diazotrophic community structures. Nitrification inhibitors significantly inhibited Methylocella but stimulated Rhizobiales and affected soil diazotrophic communities. The nitrification inhibitors DCD and DMPP significantly altered soil diazotrophic community structures, but weed management outweighed nitrification inhibitors in reshaping soil diazotrophic community structures. The non-targeted effects of the nitrification inhibitors DMPP and DCD on soil free-living N fixation were substantially influenced by the weed management methods.

Response of Soybean to Nitrogen Levels and Weed Management on Growth, Yield and Economic Efficiency

A field experiment was conducted during 2021 at the farm of Afghanistan National Agricultural Science and Technology University (ANASTU) to find out the suitable Response of Soybean to Nitrogen Levels and Weed Management on growth, yield and economic efficiency, the experimental design was Split plot design with two factors replicated thrice, the experiment consist of three weed management methods (Un-weeded check, Pendimethalin + hand weeding and Pendimethalin + Imazethapyr) and four nitrogen levels (Control, 40 kg N/ha, 60 kg N/ha and 80 kg N/ha). The maximum growth, yield and economic efficiency was in treatment (Pendimethalin + Imazethapyr), Root dry weight (9.42/plant), Nodules/plant (25.5),Nodes/plant (25.57, 27.68), Internodes distance(36.88 mm), Pods/plant(41.1), Seeds/pod (2.5), 1000 seed weight (102.5 gr), Grain yield (2.20 ton/ha), Gross Returns (187.863 AFN/ha), Net Returns (134.308 AFN/ha) and Benefit: cost ratio (2.504) compared to Un-weeded check and Pendimethalin + hand weeding, Root dry weight (9.67g/plant), Nodules/plant (25.6), Nodes/plant (27.68), Internodes distance(37.99 mm), Pods/plant(45.3), Seeds/pod (2.5), 1000 seed weight (104.7gr), Grain yield (2.20 ton/ha), Gross Returns (187.922 AFN/ha), Net Returns (133.159 AFN/ha) compared to 60 kg N/ha, 40 kg N/ha and control. it can be concluded that the application of (Pendimethalin + Imazethapyr) along with 80 kg N/ha was found to be suitable for profitable cultivation of soybean with optimum quality under the agro-climatic conditions of Kandahar Afghanistan.

Performance of Various Chemicals Weed Management in Chickpea an Irrigated Environment

Chickpea is additional sensitive to weed competition than other crops. During early stages of crop growth competition is more severe because of slow growth rate and leaf area development. Weeds have been blamed for losses in India that range from 40 to 90 percent. Thus, adopting an effective weed management strategy is the only way to significantly increase chickpea yield. The experiment was conducted during Rabi season of 2011-12 at Agronomy Research Farm of NDUA&T, Kumarganj, Ayodhya, Uttar Pradesh. The experiment was laid out in randomized block design with fourteen weed management treatments and replicated in thrice. According to the findings, weed management methods significantly affect the number of nodules, nutrient (N, P, K) uptake, yields, and economics of chickpea over weedy check at growth stage. Maximum yield (1.72 t ha-1) and nutrient uptake (N- 63.60, P- 9.09 and K- 74.39 kg ha -1) by chickpea were recorded in weed free treatment but maximum nitrogen, phosphorous and potassium (23.22, 2.68 and 50.42 kg ha -1) uptake by weed were obtained in weedy check treatment and lowest in weed free treatment.

Above Ground Emergence and Floristic Composition of Weeds in Relation to Tillage and Weed Management Practices in Maize and Cowpea

Background: Weeds are one of the most important elements influencing crop productivity. Tillage practices have a significant effect on the weed seed bank and the appearance of weeds, both of which have a direct impact on farm productivity. Different tillage strategies based on ploughing depth, as well as weed control practices, change the dynamics of weed seeds in the soil. This research will aid in the development of integrated weed control methods by investigating the interaction between tillage and weed management practices. Methods: Field trials were carried out in two seasons, Summer and Kharif 2022, using a split-plot design with three tillage methods and four weed management practices. The treatments were replicated three times. Result: Among the different tillage treatments Mouldboard plough fb Cultivator fb Rotovator recorded the lowest weed density. With respect to weed management methods, pre- and post-emergence herbicide application and hand weeding at 20 and 40 DAS recorded the lower weed density. Interaction effects of tillage and weed management practices resulted in lower weed density in Mouldboard plough fb Cultivator fb Rotovator with herbicide application and Mouldboard plough fb Cultivator fb Rotovator with hand weeding. Highest weed density was recorded under Cultivator fb Rotovator in unweeded control. With respect to relative density, among the broad-leaved weeds (BLW) Trianthema portulacastrum and Dactyloctenium aegyptium in grasses dominated among the weed species in 30 and 60 DAS respectively. From the present study it was concluded that the Mouldboard plough fb Cultivator fb Rotovator with hand weeding twice or herbicide application reduces the weed emergence from the soil weed seed bank.