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Allelopathy for weed control in agricultural systems
Abstract
Weeds are a hidden foe for crop plants, interfering with their functions and suppressing their growth and development. Yield losses of ∼34% are caused by weeds among the major crops, which are grown worldwide. These yield losses are higher than the losses caused by other pests in the crops. Sustainable weed management is needed in the wake of a huge decline in crop outputs due to weed pressure. A diversity in weed management tools ensures sustainable weed control and reduces chances of herbicide resistance development in weeds. Allelopathy as a tool, can be importantly used to combat the challenges of environmental pollution and herbicide resistance development. This review article provides a recent update regarding the practical application of allelopathy for weed control in agricultural systems. Several studies elaborate on the significance of allelopathy for weed management. Rye, sorghum, rice, sunflower, rape seed, and wheat have been documented as important allelopathic crops. These crops express their allelopathic potential by releasing allelochemicals which not only suppress weeds, but also promote underground microbial activities. Crop cultivars with allelopathic potentials can be grown to suppress weeds under field conditions. Further, several types of allelopathic plants can be intercropped with other crops to smother weeds. The use of allelopathic cover crops and mulches can reduce weed pressure in field crops. Rotating a routine crop with an allelopathic crop for one season is another method of allelopathic weed control. Importantly, plant breeding can be explored to improve the allelopathic potential of crop cultivars. In conclusion, allelopathy can be utilized for suppressing weeds in field crops. Allelopathy has a pertinent significance for ecological, sustainable, and integrated weed management systems.
... Crop rotations and tillage practice can lead to distinct weed communities (Nichols et al., 2015) and crop sequence within diverse crop rotations influence weed prevalence and management (Garrison et al., 2014). Agronomic crops that contain allelopathic compounds can play a role in weed management when used in a crop rotation (Bhowmik & Inderjit, 2003;Jabran et al., 2015). ...
... Sorghum [Sorghum bicolor (L.) Moench] is considered an important allelopathic crop with different levels of hydrophilic compounds, phenolic acids, and hydrophobic substances such as sorgolene (2-hydroxy-5-methoxy-3-[(Z,Z)-8′,11′,14′-pentadecatriene]-p-benzoquinone) which are exuded from sorghum roots (Glab et al., 2017;Jabran et al., 2015). Sorghum residues provide weed suppression by physical presence and contain allelochemicals like caffeic acid, m-coumaric acid, and chlorogenic acid (Jabran, 2017). ...
Plain Language Summary
Diversified crop rotations can provide many benefits that include greater yield stability, better nutrient cycling, and improved pest management. In a long‐term experiment, we observed weed differences in oat that was the result of whether the previous crop was corn or grain sorghum. Horseweed, a common weed in North America, was more prevalent in oat when the previous crop was corn. We speculate that grain sorghum, considered to have allelopathic compounds, suppressed horseweed the following year better than corn. We show that crop sequence within diversified can result in distinct differences in weed presence and production.
... A diet with the ideal composition of nutrients can be the most easily found in an environment with a high diversity of resources. In these conditions, animals can feed on various plant species with a different content of nutrients [ 87 ] as have been shown by Trinkl et al. [54]. The authors have analyzed the nutritional composition of the larval feed obtained from bee colonies located in various environments with floral diversity. ...
... Each individual in an ecosystem releases different metabolic products into the environment and thus creates specific environmental conditions, which might be toxic, favorable or neutral for nearby plants, phytophagous insects, and microorganisms [86]. In 1996, the International Allelopathy Society expanded its definition of allelochemical interactions by including any processes with the secondary metabolites produced by plants, microorganisms, viruses, and fungi and influencing the growth and development of agricultural and biological systems [87]. Allelopathic interactions are one of the most complex interactions because both direct and indirect effects are intertwined in this form. ...
Relevance. Trophic relationships along with competition and mutualism are the most basic and significant interactions in ecosystems. To develop, survive, and multiply, insects need to consume a certain amount of nutrients at a certain ratio. Food products are complex mixes of nutrients and non-nutritive substances (sometimes toxic ones): macronutrients (proteins, carbohydrates, and lipids), micronutrients (vitamins and minerals), and water. Some nutrients are essential; insects lack the ability to synthesize them in their bodies and must obtain them from their diet or through symbiosis with beneficial organisms. Identification mechanisms being well developed in the system “phytophagous insect – plant” allow insects to successfully spread, multiply, and feed on certain plant species. The complex of hydrolytic enzymes in the insect intestine is one of the main targets for plant defense responses because these enzymes determine the availability of structural compounds for phytophagous insects. For this reason, enzymes in the insect intestine play a key role in the adaptation of insects to the pest resistance of fodder plants. For instance, when proteinase inhibitors are synthesized in a fodder plant as the result of induced insect resistance the complex of enzymes in an insect intestine might change negating the effect of these inhibitors. The development of co-adaptations due to interactions among species in food chains depends on a complicated constellation of conflicting relationships between consumers and food objects. The mechanisms of this influence may be rooted in the allelochemical interactions in the system “phytophagous insect – plant recipient”. Allelopathic interactions are among the most complex interactions because they are constituted by direct and indirect effects. Plants when damaged by phytophagous insects activate defense responses, which incorporate several mechanisms, including an increase in the concentration of secondary metabolites, many of which are phenolic compounds.The aim of the work is to describe the mechanisms of relationships in the system “phytophage-plant”. Conclusion. Management of processes of intra-water divergence of insect-phytophages in agrobiocoenoses in order to prevent the emergence of races and populations of pests adapted to live on initially resistant to them plant forms is possible in compliance with the transition to a targeted selection of agricultural crops for resistance to a complex of pests.
... Among various allelopathic crops, sorghum is one of the most allelopathic crops having many number of allelochemicals which suppresses the growth of weeds and increase microbial population (Jabran et al., 2015). Many secondary metabolites such as phenolic, alkaloids, flavonoids, and terpeniods are identified in sorghum plant (Jabran et al., 2015;Pagare et al., 2015). ...
... Among various allelopathic crops, sorghum is one of the most allelopathic crops having many number of allelochemicals which suppresses the growth of weeds and increase microbial population (Jabran et al., 2015). Many secondary metabolites such as phenolic, alkaloids, flavonoids, and terpeniods are identified in sorghum plant (Jabran et al., 2015;Pagare et al., 2015). In phenolic doi: 10.48165/jefa.2024.19.02.9 ...
Assessment of soil micro flora and yield of wheat (Triticum aestivum L.) through post-emergence and sequential application of sorghum extract and herbicide ABSTRACT Wheat is one of the most important crop among the cereals in the world. This crop supplies over 20 per cent of the food calories to the world growing population and also stands at 2nd place under staple food crops next to rice in India. The treatments included sorghum extract and clodinafop + metsulfuron herbicide alone as well as mix to control weeds with weed free and weedy checks. Maximum population of soil bacteria (Bacillus spp., Pseudomonas spp. and Xanthomonas spp.) and soil fungus (Aspergillus niger, Rhizopus spp. and Mucor spp.) were obtained under lower concentration of sorghum extract (1:3) at 60 DAS and at harvest stages of crop, respectively, which measured in terms of magnitude improvements as compared to the population recorded before spraying. Thereafter, treatment which contained very lower concentration of sorghum extract (1:4) which also showed their effects on increasing population of soil bacteria and fungus at 60 DAS and at harvest stages of wheat, respectively, and both the treatments superiority over other sorghum extract and herbicidal treatment tested during investigation. Sorghum extract application showed positive effect on the soil microbial population.
... Natural products, such as essential oils, agricultural byproducts, certain pathogens, and water extracts from many plant species, are gaining increasing attention for their use in weed management [16]. Including cover crops in crop rotation has been shown to effectively control weeds [17] due to the competitive and allelopathic nature of these plants [18]. Consequently, water extracts from allelopathic cover crops have an inhibitory effect on weed growth in plenty of in vitro studies [19,20]. ...
... Consequently, water extracts from allelopathic cover crops have an inhibitory effect on weed growth in plenty of in vitro studies [19,20]. These natural biochemicals present in plants, secondary plant metabolites [21], vary in composition and concentration in different parts of the plant [18] and thus also in the type of natural herbicide (essential oil, water extract, seed meal, etc.) that is used. ...
With the increasing demand for non-chemical weed control methods, phenolic acids have shown promise due to their natural weed inhibitory potential. In this study, the inhibitory effect of ferulic acid, vanillic acid and p-coumaric acid was investigated on Ambrosia artemisiifolia L. and the selectivity of Zea mays L. against these phenolic acids was tested. The seeds of A. artemisiifolia and Z. mays were treated in vitro with three phenolic acids at doses of 200–600 × 10⁻⁷ mol and in vivo foliar on A. artemisiifolia and Z. mays plants. While all phenolic acids had effects on the early growth of A. artemisiifolia, p-coumaric acid significantly reduced the length of radicle and hypocotyl by more than 60% while the effects on Z. mays were minimal. In vivo assessments using chlorophyll fluorescence and multispectral imaging showed selective stress responses in A. artemisiifolia but not in Z. mays after foliar application. The in vitro results show that p-coumaric acid is a promising compound for the control of A. artemisiifolia. However, these phenolic acids at these doses led to an insufficient reduction in photochemical efficiency. Therefore, these natural compounds need to be combined with other methods of weed control.
... The negative effects of weeds on crop yield exceeds that of plant pathogens [2]. Weeds compete with agricultural crops for essential resources including water, light, nutrients, and physical space, impending crops' normal functioning and surpassing their growth and development [3]. They also serve as hosts for pests and crop pathogens [4]. ...
... Among these alternative methods, the use of natural plant products has attracted the attention of researchers [12,13] and can be a solution to the challenge of resistance to herbicides and environmental pollution [3]. In this method, some plants, due to the presence of toxic gases (cyanogenic glucosides, hydrogen cyanide, amygdalin, etc.), organic acids and aldehydes (malic acid, citric acid, acetaldehyde), aromatic acids (ferotic acid, benzoic acids, etc.), simple unsaturated lactones (patolin, parasorbic acid, etc.), coumarins (coumarin, esculin, scopolin, etc.), quinones (juglone), flavonoids (phlorizin, rotenone), tannins (nitrapyrin), alkaloids (caffeine, quinine, berberine, etc.), terpenoids and steroids (camphene, dipentene, camphor, β-pinene, etc.) and other unknown substances (alcohols, polypeptides, and nucleosides) act as natural herbicides and pesticides [9,14]. ...
Large quantities of chemical herbicides are used in agroecosystems every year, which not only imposes a significant financial burden on farmers but also leads to environmental pollution. To address this challenge, the present study aimed to replace Treflan with Fedaleh essential oils (EO). Treflan is a commonly used chemical herbicide for spring-summer crops, and Chenopodium album has been chosen as a prevalent and abundant weed in many agricultural ecosystems. Four types of inhibitors, including Treflan herbicide and essential oils extracted from the leaf, stem, and flower of Fedaleh, were used in this experiment. These inhibitors were tested at five different concentrations: 0, 0.5, 1, 2, and 5 μL/mL. Based on GC-MS results, the key compounds found in Fedaleh EO were α-pinene, α-phellandrene, γ-terpinene, linalool, sabinol, β-myrcene, neric acid, carvacrol, β-phellandrene, thymol, and spathulenol. A dose-dependent increase in hydrogen peroxide, malondialdehyde, electrolyte leakage, and proline content was observed with Fedaleh EO or Treflan. However, a decline in cell viability, germination, radicle length, radicle weight, plumule length, plumule weight, and seedling vigor index was observed in a dose-dependent manner with Fedaleh EO or Treflan. The weight of the radicle and plumule was noticeably decreased by 27 %, 28 %, and 14 %, 19 % respectively when treated with essential oils derived from the stem and flower of the Fedaleh, as compared to Treflan. Interestingly, at concentrations of 5 μL/mL EO, the germination, radicle length, plumule length, and seedling vigor index significantly decreased by 64–72 %, 56-56 %, 41–44 % and 90–93 % % as compared with control, respectively. The essential oils extracted from different parts of Fedaleh showed no significant difference in terms of hydrogen peroxide, electrolyte leakage, cell viability, and proline content, compared to Treflan (P > 0.05). Compared to the control, Treflan did not affect germination (P > 0.05), but the EO of Fedaleh's different parts significantly inhibited germination (P < 0.05). The growth inhibitors at a concentration of ≥1 μL/mL significantly reduced the length of the radicle and plumule in Chenopodium album. Overall, Fedaleh EO has significant potential as a growth inhibitor and oxidative stress inducer to prevent weed interference. This makes it a suitable option for the commercial production of a natural herbicide.
... Weeds are the most damaging biotic constraint to agricultural production and compete with crops resulting in considerable productivity loss (Jabran et al., 2015;Gharde et al., 2018). Weeds impede crops by competing with the standing crop for nutrition and other resources, which stifle crop growth and development. ...
... Bioherbicides refer to natural products derived from living organisms or their natural metabolites; they are used to control weed populations without harming the environment (El-Amier & Abdullah, 2014). Allelopathy can be used in weed management and comply with environmental issues and is cost-effective (El-Amier & Abdullah, 2014;Jabran et al., 2015). This method provides an alternative for the development of environmentally friendly agricultural practices that increase crop productivity and support ecosystem stability (Scavo et al., 2018). ...
Weeds cause significant yield loss in many agriculture crops; thus, management practices are urgently needed to alleviate losses while conserving environmental and human health. This study aimed to evaluate the allelopathic potential of Wedelia leaf and flower extracts on the germination and early growth stage of three plant species. The research was conducted using a completely randomized design experiment with two factors and four replicates. The first factor was extract sources: leaves (S1) and flowers (S2). The second factor was the concentration: control (C0) and extract concentrations of 1% (C1), 5% (C5), and 10% (C10). The extract was tested on three different plant species: soybean (Glycine max), nutsedge (Cyperus rotundus), and billygoat weed (Ageratum conyzoides). Fifty seeds of three different plants were germinated separately in Petri dishes and treated using Wedelia extracts. The allelochemicals in Wedelia leaf and flower extracts inhibited germination and induced abnormal sprouting. Wedelia leaf extract showed the most pronounced inhibitory effects and highest inhibition levels across all measured parameters. Moreover, a clear concentration-response relationship was observed, where increased extract concentration increased the degree of inhibition. These findings contribute to the development of bioherbicides and can help reduce the use of synthetic herbicides for more sustainable agriculture. Keywords: Ageratum conyzoides, bioherbicide, Cyperus rotundus, Glycine max, weed control
... Weed suppression level is directly related to the dose of allelopathic products [47,48]. The higher the amount of plant material used for mulch, the greater the total amount of allelochemicals present in the mulch and released, leading to a higher concentration of allelochemicals into the soil [49][50][51]. Generally, by incorporating a higher amount of crop residues, greater weed suppression was observed. ...
... They provide nitrogen by releasing it into the rhizosphere soil of the tested crop plant. The application of sorghum residues as biological weed management helps in the mineralization of nitrogen and enhances nitrogen availability in the rhizosphere [7,14,50]. However, at later stages of crop growth, the obtainability of nitrogen was improved by mineralization, so this sustained supply of nitrogen was a nonstop source of nutrition for test crops as well as next crops. ...
... These allelopathic substances possess phytotoxic properties that make them suitable for use as natural herbicides. Using naturally occurring allelochemicals for weed management is an excellent arena for discovering novel herbicides (Jabran et al. 2015). Certain weed species can be utilized to prepare natural herbicides (Qasem and Foy 2001). ...
Medicinal plants have remained a promising panacea for various health problems since ancient times. Trianthema portulacastrum L. (Family: Aizoaceae) is a small, diffused, annual and branched weed native to South Africa and also distributed in America, Baluchistan, India and West Asia. It is one of the significant medicinal herbs used for a variety of culinary and healthcare practices all over the world. Traditionally, it was used for the treatment of jaundice, asthma, throat infections and rheumatism. It is also helpful in treating alcohol poisoning. Its fleshy leaves are used for wound healing. The medicinal herb is a rich reservoir of therapeutically useful bioactive constituents, viz. flavonoids, saponins, alkaloids, steroids, terpenoids, tannins, glycosides and phenols. This plant possesses several pharmacological activities, such as antioxidant, antimicrobial, anti-inflammatory, analgesic, anti-fungal, anti-pyretic, anticancer, hypoglycemic and hepatoprotective. The present review is an effort to consolidate the available information on its ethnobotany, phytochemistry, pharmacological actions with possible mechanisms of action, toxicological studies, and recent advances. The phytotoxic potential of this weed has also been highlighted which may serve as a source for developing potent herbicides. The findings of this article may provide useful leads for pharmaceutical scientists, food scientists and herbal health practitioners to search for new drugs. The findings may also be beneficial for preparing a monograph of plants for future research aspects. Further comprehensive research is needed to evaluate molecular modes of action and ascertain efficacious doses of T. portulacastrum.
Graphical abstract
... This competition is responsible for them being considered a pest since they affect the productivity of crops and make agricultural activities difficult because treating their invasion requires additional work, thus causing economic losses in more ways than one (Chauhan, 2020). The effect of the weed on the plants of interest is dependent on various factors, such as the origin of the invasive species, the climate, the crop plant used, and even the other species present in the environment that may or may not act as biocontrol of the weeds, such as some kinds of insects ( Jabran et al., 2015). ...
The objective of this chapter was to summarize recent and valuable information about the traditional management of pests, the use of nanotechnology in the agriculture sector, formulation as well as their diverse applications in food production.
... El creciente número de malas hierbas resistentes a herbicidas supone una importante amenaza para la producción de cultivos, causando más del 34% de las pérdidas económicas en los agroecosistemas (Jabran et al., 2015). El 47,5% del total de insumos químicos utilizados en los campos a nivel mundial son herbicidas debido a su eficacia para combatir las malas hierbas (Sharma et al., 2019), sin embargo, el uso masivo y continuado ha reportado daños en los ecosistemas y salud humana (Ustuner et al., 2020). ...
Excessive use of synthetic herbicides can cause environmental and public health problems, as well as herbicide-resistant weeds, so it is imperative to find a more sustainable method of weed management. In this study, twenty-nine accessions of two buckwheat species (Fagopyrum esculentum Moench (common buckwheat) and Fagopyrum tataricum (L.) Gaertn. (tartar buckwheat) were evaluated against two synthetic herbicide resistant weeds, the monocotyledonous Lolium rigidum Gaud. and the dicot Portulaca oleracea L. The results suggest that buckwheat accessions can sustainably manage both weed species through plant interference such as competition or allelopathy. We found that F. esculentum accessions were more effective against L. rigidum and F. tataricum accessions against both weeds. The study also included analysis of the chemical profile of the buckwheat accessions (plant polyphenol content) in order to relate it to the ability to sustainably manage weeds. Common buckwheat accessions showed more orietin, vitexin and hyperoside, while tartar buckwheat accessions showed higher amounts of rutin, quercetin and kaempferol which may be responsible for the different effects observed on weed growth. We propose that screening and selection of accessions with high polyphenol content and good growth may be a step towards organic farming due to their positive relationship with sustainable weed management.
... Furthermore, by employing a range of methodologies, it becomes feasible to attain further enhancements in the accumulation of secondary compounds at both local and global levels (Shahzad et al., 2017). The research conducted by Jabran et al. (2015) examined the application of hairy root cultures as a means of synthesizing secondary metabolites present in nontransgenic roots. The documented literature extensively covers the qualifications of hairy root culture techniques to produce secondary compounds. ...
This review centers on the classification of secondary metabolites into three main groups, as previously mentioned. The objective is to present their pharmacological properties, which possess the capacity to facilitate the identification and advancement of novel pharmaceuticals. The analysis of plant constituents necessitates careful examination of a complex amalgamation of diverse chemical compounds, with the objective of optimizing the methodology to discern and
extract a biologically active compound. To examine the biological characteristics of a specific medicinal plant, it is often necessary to utilize purification methods or isolate a particular compound.
... Globally, rice allelopathy research has expanded, particularly in regions where continuous rice cropping has intensified weed pressure and heightened dependence on chemical herbicides. A growing body of research has identified various allelopathic compounds in rice, such as momilactones and phenolic acids, which effectively inhibit weed germination and growth (Khanh et al., 2007;Scavo & Mauromicale, 2021 (Jabran et al., 2015;Macías et al., 2019). Looking ahead, rice allelopathy holds dual benefits: enhancing weed suppression while contributing to the global shift towards sustainable agriculture. ...
N‐trans ‐cinnamoyltyramine (NTCT) has been identified from an allelopathic Vietnamese rice accession OM 5930. This study employed bioassays to analyze NTCT's effects on shoot and root growth of multiple test and weed species. NTCT demonstrated potent inhibitory effects on cress, lettuce, canola, palmer amaranth, timothy, barnyardgrass, red sprangletop, and weedy rice, with increasing concentrations leading to substantial reductions in growth in all species. Linear regression analysis of dose response curves revealed ED 50 values for NTCT, providing critical insights into the concentration required for 50% growth inhibition in each species. They revealed high sensitivity of the test species cress and lettuce, intermediate sensitivities of barnyardgrass, red sprangletop, timothy, and amaranth, and comparatively lower sensitivity of two weedy rice accessions. The findings underscore NTCT's efficacy in suppressing the growth of a wide range of weeds, including both grasses and broadleaf species. As such, NTCT may hold promise as a tool for sustainable weed management, particularly in addressing herbicide‐resistant weeds in diverse ecological settings.
... Furthermore, in other instances, Kubiak et al. (2022) argue that weeds release allelopathic substances into the soil, further developing crop pathogens and pests. Jabran et al. (2015) also report that allelopathy can be adopted to suppress weeds within field crops. The intense competition between the crops and weeds for nutrients negatively impacts crop yields. ...
Pests and insects are a pertinent challenge affecting the sustainability of modern agriculture and, as a result, threatening global food security. The Food and Agriculture Organization (FAO) estimates that up to 40% of global crop production is lost to pests and diseases, where plant diseases cost the economy 70 billion. Therefore, identifying strategies to address pests and insects is integral to enhancing food security and sustainable agriculture. Diverse strategies ranging from synthetic pesticides to biological pest control techniques are often used to control pests and insects in modern agriculture. However, the focus of this chapter was to explore the use of nanotechnology in aiding the manufacture of biopesticides. Based on the conducted review, it emerged that nanotechnology aided the manufacture of pesticides through liquid- and solid-state fermentation techniques. The insights also showed that using nanotechnology was beneficial in manufacture of biopesticides due to the targeted release of biochemicals, reduced harm on the environment and the optimal use of agrochemicals depending on the environmental conditions and crop requirements. In the future, it is expected that nanotechnology will be utilized as a viable option for replacing synthetic agrochemicals. Future directions also emphasize on improving safety associated with nanopesticides and reducing the complexity of production processes. The chapter further recommends researchers to establish an understanding of the degradation mechanisms of biopolymers in order to improve the design of more precise, predictable release profiles. Additionally, creating awareness of the use of nanotechnology to improve its application is also advocated.
... Many weeds are associated with barley threat to crop production and cause considerable economic losses as narrow-leafed weeds especially darnel weed Lolium temulentum [3]. With the aim of reducing reliance on chemical pesticides in weeds control because of their environmental and health damages such as application in inappropriate weather conditions or at the incorrect developmental crop stage, could lead to dangerous environmental consequences, such as the leaching of chemically active compounds into groundwater or residual accumulation in the soil [4], as well as the emergence of resistance to herbicides in weeds [5], For this, the researchers looked for new control methods, use allelopathic substances one of environmentally friendly and effective alternatives to control weeds [6]. Sorghum is one of the crops that has been reported to show allelopathic effects [7], Many allelochemicals have been recorded in different parts of the Sorghum (roots, stems, foliage, and panicle) [8].The farmers often ask about the reasons for the effect of sorghum on subsequent crops without getting a correct scientific answer. ...
The aim of the study was to investigate phytochemical compounds of aqueous
extracts leaves of three growth stages of Sorghum ., and the study the effect of those three
aqueous extracts on the darnel weed associated with the barley. The GC-MS method was used
to screen the phytochemical compounds of three-stage of growth Sorghum which showed
diagnosis a number of compounds depending on the retention time such as Daucol, 13-
Octadecenal, and Oleic Acid for growth stage 4-6 leaves, and 2,2-Dimethylpropanoic acid, 1-
Eicosanol, and Batilol for growth stage 8-10 leaves, and Hexadecanoic acid, Bis(2-ethylhexyl)
phthalate and 1-Docosene for growth stage 12-14 leaves. The results showed significant effects
of aqueous extracts leaves of Sorghum in the percentage of control dernal weed where recorded
64.133, 85.360, and 86.427% after 30, 60, and 90 days of treatment at growth stage 12-14
leaves of Sorghum compared with 0.00,0.00 and 0.00 in the control treatment.
... Agricultural crops' productivity can decrease by 45-95% just due to the presence of weeds [1,2]. Synthetic herbicide application is considered to be the most successful method for weed control, but its widespread usage in the past several decades has resulted in a number of issues regarding human health and the environment, as well as herbicide resistance development [3]. ...
Sesquiterpene lactones (SLs) are compounds that are highly produced in Cynara cardunculus leaves, known for their phytotoxic activity. This study aims to assess SL-enriched fractions’ (cynaropicrin, aguerin B, and grosheimin) phytotoxic potentials and putative modes of action, compared to an initial extract, using two approaches: first, against a panel of nine weed species in pre-emergence, and then on Portulaca oleracea L.’s post-emergency stage. The SL-enriched fractions demonstrated greater phytotoxic activity when compared with the C. cardunculus leaf initial extract. The SL-enriched fractions had higher activity at root growth inhibition over the panel tested, doubling the activity in five of them at 800 ppm. Regarding the post-emergence bioassay, the SL-enriched fractions had a higher influence on the plants’ growth inhibition (67% at 800 ppm). The SL-effects on the plants’ metabolisms were evidenced. The total chlorophyll content was reduced by 65% at 800 ppm. Oxidative stress induction was observed because of the enhancement in MDA levels at 800 ppm compared to control (52%) and the decrease in SOD-specific activity from 4.20 U/mg protein (400 ppm) to 1.74 U/mg protein (800 ppm). The phytotoxic effects of the SL-enriched fractions suggest that they could be used for a future bioherbicide development.
... Weeds can reduce crop output by an average of 34%. Te output of some essential crops has been reduced by weeds as follows: cotton 36%, maize 40%, potatoes 30%, rice 37%, and wheat 23% [3]. Synthetic herbicides often have adverse impacts on both the environment and humans. ...
Background. The aim of the study was to investigate the cytotoxicity, phytotoxicity, and proximate and phytochemical analysis of methanolic extracts of the leaves of Justicia adhatoda. Methods. Methanolic leaf extract of J. adhatoda was screened for phytotoxic activity by using root length inhibition and seed germination assays. Cytotoxic activity was calculated using brine shrimp lethality bioassay. Plant extracts were also investigated for their proximate composition. The presence of several phytochemicals was tested by employing different methods. Results. Decrease in seed germination and root length, 62.67% and 83.11%, was proportional to the increasing concentration of the methanolic extract of the plant. Cytotoxicity assay results indicated that the methanolic extract possessed significant cytotoxic potential with an LC-50 of 217 µg/ml. Proximate analysis revealed that the leaves of J. adhatoda contain 9.4% moisture, 90.6% dry matter, 19.25% crude protein, 4.5% crude fat, 8.0% crude fiber, and 11.5% total ash. Conclusion. Methanolic extracts of J. adhatoda leaves showed significant cytotoxic effects and may have potential use in medicine. The J. adhatoda foliar extract shows good inhibitory effects against seed germination and root growth. Therefore, it might be used as soil additive in crops to control weeds. Further research is required to detect and isolate phytotoxins from the plant that might replace synthetic herbicides with eco-friendly herbicides.
... In addition, the synergistic effect between plants can be benefited by taking it into the appropriate agricultural rotation system (Bellostas et al., 2007;Jabran, 2017;Acar et al., 2019). Several studies showed the allelopathic potential of many plants of the cruciferous family and their efficiency in weed control (Uremis et al., 2009;Bangarwa et al., 2011;Jabran et al., 2015;Elsekran, 2022;Elsekran & Ustuner, 2024). It was reported that when the Brassica napus plant was incorporated into the soil, it inhibited weed biomass by 96% in subsequent potato production (Boydston & Hang, 1995). ...
This study aimed to investigate the effectiveness of black radish and garden cress as pre-plant in field trials and their aqueous extracts under greenhouse conditions to control johnsongrass. In the field experiment, black radish and garden cress were grown as a pre-plant, then mixed with the soil and used with and without mulch against johnsongrass. The effects of these applications on johnsongrass development and tomato yield and quality were evaluated. Different concentrations of pre-plant extracts (2, 5, and 10%) were also investigated on johnsongrass and tomato seedling growth in greenhouse conditions. The lowest johnsongrass density was recorded in black radish and garden cress with mulch (106.7 and 97.2 number m-2). Black radish and garden cress with mulch achieved johnsongrass control efficiency of 80.2 and 84.0% compared to those without mulch 56.8 and 58.2%. The effect of all treatments was positive in increasing the quantity and improving the quality of tomato production. The results of greenhouse experiments showed that high concentrations (10%) of black radish and garden cress extracts achieved high levels in preventing the germination and growth of johnsongrass. In these treatments, johnsongrass seeds and rhizomes germination rates were 17.5 and 7.5%, 20.0 and 12.5% respectively. GC-MS analysis showed that five isothiocyanates (ITCs) were in black radish, and their total percentages were 40.4%. In the garden cress, it was found that there is only one ITC with a percentage of 61.0%. Black radish and garden cress effectively inhibit the germination and growth of Johnsongrass due to their allelopathy effects. Sustainable management of johnsongrass can be achieved by introducing these plants into a crop rotation which may be an alternative or reduce the use of herbicides. Herbology Research Article Keywords Black radish (Raphanus sativus L. var. niger J. Kern.) Garden cress(Lepidium sativum L.) Johnsongrass (Sorghum halepense (L.) Pers.) Tomato Allelopathy Domates Yetiştiriciliğinde Siyah Turp (Raphanus sativus L. var. niger J. Kern.) ve Tere (Lepidium sativum L.) Bitkilerinin Geliç (Sorghum halepense (L.) Pers.) Bitkisi Üzerine Allelopatik Etkileri ÖZET Bu çalışma, geliç mücadelede tarla denemelerinde ön bitki ve sera koşullarında sulu özüt olarak siyah turp ve tere etkinliğini araştırmayı amaçlamıştır. Tarla denemesinde siyah turp ve tere ön bitki olarak tarlada yetiştirildikten sonra toprağa karıştırılarak geliç'e karşı malçlı ve malçsız olarak kullanılmıştır. Bu uygulamaların geliç'in gelişmesine ve domates verim ve kalitesine etkileri değerlendirilmiştir. Sera koşullarında ön bitki özütlerinin farklı konsantrasyonlarının (%2, 5 ve 10), geliç ve domates fide büyümesi üzerine etkileri de araştırılmıştır. En düşük geliç yoğunluğu malçlı siyah turp ve tere uygulamalarda kaydedilmiştir (106.7 ve 97.2 adet m-2). Malçlı siyah turp ve tere uygulamalarda geliç'in mücadele etkinliği %80.2 ve %84.0 olurken malçsız uygulamalarda %56.8 ve %58.2 kayıt edilmiştir. Tüm uygulamaların etkisi domates üretim miktar ve kalitesinin arttırılmasında olumlu olarak değerlendirilmiştir. Sera deneme sonuçları, siyah turp ve tere özütleri yüksek konsantrasyonlarının (%10) geliçin çimlenme ve büyümesini önlemede yüksek seviyede etkili Herboloji Araştırma Makalesi Makale Tarihçesi Geliş Tarihi : 08.02.2024 Kabul Tarihi : 18.07.2024 Anahtar Kelimeler Siyah turp (Raphanus sativus L. var. niger J. Kern.) Tere (Lepidium sativum L.) Geliç (Sorghum halepense (L.) Pers.) Domates Allelopati KSÜ
... According to several studies, the annual losses caused by weeds around the world are estimated to be 13.2 % or 75.6 billion USD. This includes losses of 2.7 billion USD in Australia, 5 billion USD in the United States, and 11 billion USD in India [6][7][8][9] In some cases, the damage caused by weeds can reach 100 % without proper control measures, and even with control measures in place, yield losses of up to 20 % have been reported in wheat production due to technical failures. Implementing effective weed control measures is crucial for maintaining crop productivity and reducing economic losses [1,[10][11][12]. ...
... J. Sun et al., 2016). Additionally, rice allelopathy plays a vital role in weed inhibition (Jabran et al., 2015). The Taichung Native 1 (TN1) had the ability to inhibit the 65%-84% of weed, while the PI312777 was 65% (Y. ...
While traditionally perceived as yield‐reducing elements in rice (Oryza sativa L.) cultivation, weed communities in paddy fields play a crucial role in the ecosystem. These communities, when selectively retained, can significantly enhance ecosystem services. This review examines the impact of various weed communities on rice in different paddy fields, their response to field nutrients, and the ecological benefits they offer. These benefits include nitrogen retention, promotion of microbial diversity, and reduction of diseases, pests, and weed proliferation. Examples of such benefits are seen in weeds like Lemna minor L. and Azolla imbricata (Roxb.) Nakai, which help in nitrogen fixation and act as biocontrol agents against harmful pests. However, current research in this area faces challenges, including the lack of intelligent and precise weed control technologies, comprehensive green control strategies, and expertise in weed management. Our findings suggest a strategic approach to weed control in paddy fields, emphasizing the importance of preserving weed species that have minimal impact on rice yields but offer significant ecological advantages. These practices can lead to grass‐mediated weed control and enhanced nutrient absorption, thereby reducing fertilizer loss. Ultimately, this approach could reduce the reliance on chemical fertilizers and herbicides in paddy fields, laying the groundwork for greener rice cultivation and sustainable agricultural practices.
... However, the higher soil moisture promoted by cover crops residues can increase weed seed germination (Gerhards & Schappert, 2019). Some cover crops also have allelopathic potential by suppressing weeds (Jabran et al., 2015). On the other hand, in areas that are kept in fallow in the off-season, high reproduction of these plants is evident, resulting in an increase in the seed bank in the soil and thus contributing to greater infestations in crops in sequence, increasing costs and hindering control (Lima et al., 2014). ...
The combination of management practices affects weed populations and biodiversity. The objective was to evaluate the infesting weed community in the implementation of a corn silage (Zea mays L.) /pearl millet (Pennisetum glaucum L)/corn silage succession system subjected to early potassium fertilization in the winter crop. The experiment began in October 2019 under fallow area. In the 2019/20 summer season, corn silage was grown in a complete area. In the 2020 fall/winter season, the plots consisted of pearl millet, six doses of potassium fertilization (0, 30, 60, 90, 120 and 150 kg ha⁻¹) and one fallow. In the 2020/21 summer season, the treatments consisted of corn silage and six doses of K2O, complementing the treatment applied in the previous harvest (120, 90, 60, 30, 0 kg ha⁻¹) and one with recommended fertilization. Phytosociological evaluations of weeds were performed using a 0.25 m² square. The density and number of species increased in the first year. Early fertilization at doses of 90, 120 and 150 kg ha⁻¹ of K2O increased the dry weight of weeds before planting and at V4 stage of the corn silage cultivated in sequence; however, were lower than those for plots fallowed in the winter.
Keywords
phytosociology; corn silage; pearl millet
... Figure 4 illustrates some of breeding techniques to either introduce allelopathy de novo or increase the inherent allelopathic capacity of crops (Tranel et al. 2009). The most researched allelopathic crops that exhibit notable cultivar-specific differences in allelochemicals (momilactones, benzoxazinoids, and phenolic acids) are rye, barley, rice, and sorghum (Jabran et al. 2015). A number of genetic engineering (GE) techniques, including overexpressing genes, polymerase chain reaction (PCR), recombinant DNA, and metabolic engineering, are presently being studied to gain further insight into the enzymes, metabolic pathways, and genes involved in the production of allelochemicals (Soltys et al. 2013). ...
Allelopathy, the phenomenon in which plants release biochemical compounds that influence the growth and development of neighbouring plants, presents promising opportunities for revolutionizing agriculture towards sustainability. This abstract explores the role of biotechnological advancements in unlocking the potential of allelopathy for sustainable crop production and its applications in agriculture, ecology, and natural resource management. By combining molecular, genetic, biochemical, and bioinformatic tools, researchers can unravel the complexities of allelopathic interactions and their potential for sustainable crop production and environmental stewardship. The development of novel management methods for weed control is getting a lot of attention with the introduction of new genetic technologies such as Gene drive, Transgene technologies, Gene silencing, Marker-assisted selection (MAS), and Clustered regularly interspaced short palindromic repeats (CRISPR-Cas9). By strengthening competitive characteristics these tools hold great promise for boosting crops’ ability to compete with weeds. Considering recent literature, this review highlights the genetic, transcriptomics, and metabolomics approaches to allelopathy. Employing allelopathic properties in agriculture offer sustainable benefits like natural weed management, pest management, and reduced chemical pollution, but challenges include environmental factors, toxicity, regulatory hurdles, and limited resources. Effective integration requires continued research, regulatory support, and farmer education . Also, we aimed to identify the biotechnological domains requiring more investigation and to provide the basis for future advances through this assessment.
... Winter rye DBP = days before planting; DAP = days after planting; and ns = not significant. CC releases allelochemicals (i.e., benzoxazinones; Jabran et al., 2015), while brassicas contain glucosinolates (Kunz et al., 2016). ...
Delaying cover crop (CC) termination until or after row crop planting, known as planting green (PG), could boost CC biomass production and ecosystem services relative to the traditional CC termination (usually 1–3 weeks before crop planting). Yet, this potential has not been widely discussed. We reviewed the literature to compare CC biomass production, soil erodibility, soil water, soil C, nitrate leaching, weed suppression, insect population, disease and pest incidence risks, and crop yields between PG and traditional CC termination. Most (>95%) PG studies were: (1) from U.S. temperate regions, (2) short-term (<3 years), and (3) in winter rye CC managed in no-till corn and soybean production systems. Across studies, CC produced 1.09–11.26 times (2.56 times average) more biomass in PG than in the traditional CC termination. Cover crops in PG produced 0.117 Mg biomass ha–1 d–1. Soil C and other properties did not respond to PG in most studies, although data were few. Soil water content was lower at crop planting and greater after CC termination in PG. Cover crops in PG often suppressed weeds but increased or had no effect on disease and pest incidence. They had mixed or no effect on crop yields in 68% of studies (13 of 19) but had reduced yields in 32%, suggesting PG may not be detrimental to crop production in most cases. Long-term (>10 years) studies are lacking to better understand ecosystem services from PG and establish optimum CC termination timings. Overall, PG has mixed effects on soil properties, soil C, insect population, diseases, pests, and crop yields, but PG can suppress weeds.
... Many plants produce allelochemicals, which are secondary metabolites such as terpenoids, hydroxylated aromatic compounds, and phenolics that are produced through various metabolic pathways that effect the growth of other plants (Duryea et al., 1999;Singh et al., 2003;Farooq et al., 2020). These chemicals often act as germination or growth inhibitors for surrounding plants, providing a competitive advantage for the plant that produces the allelochemical (Farooq et al., 2020;Hadacek, 2002;Jabran, 2017;Jabran et al., 2015). Various organic mulches have been identified that possess allelopathic properties such as pine bark, shredded wood chips, black walnut wood chips, red maple leaves and shredded cypress (Rathinasabapathi et al., 2005;Duryea et al., 1999;Henschke and Politycka, 2016;Stein, 1988). ...
Liverwort ( Marchantia polymorpha ) is a problematic weed in ornamental crop production. The major limitation of liverwort control is lack of herbicide options inside greenhouses and their potential to cause injury. The current research was undertaken to study the effectiveness of allelopathic properties of six different organic mulches including rice hull (RH), cocoa hull (CH), pine bark (PB), maple leaf (ML), shredded cypress (SC), and red hardwood (HW) for liverwort control. Mulch extracts were prepared and used to impregnate agar media at an increasing dose at 1X (2 mL mulch extract), 2X (4 mL), 3X (6 mL), and 4X (8 mL) rates, in a randomized complete block design. Ten liverwort gemmae were transferred to each petri dish and they were maintained inside a growth chamber. The number of gemmae germinating in each petri dish after 1 week and gemmae surviving at the end of 2 weeks was recorded. In greenhouse study, mulch extracts were applied to containers filled with substrate for assessing liverwort control. The mulch extracts or no extract (control) were applied to the containers uniformly at 1X (15 mL), 2X (30 mL), 3X (45 mL) or 4X (60 mL) rates, in a randomized complete block design. The percentage of substrate surface covered by liverwort thalli was visually estimated bi-weekly for 10 weeks. Fresh biomass of the thalli and gemmae cup counts in each pot were also recorded. After 1 week in the growth chamber, ML followed by SC, PB and RH extracts showed maximum suppression of liverwort gemmae germination. At 2 weeks, ML applied at either of the rates provided complete inhibition of liverwort growth. In greenhouse, all the mulch extracts were able to provide complete liverwort control for the first two weeks. All the mulches and rates of applications were significantly different from the control after 6, 8, and 10 weeks. PB and HW mulches showed excellent liverwort control and minimum fresh biomass of liverwort after 10 weeks as compared to other mulches. The allelopathic potential of the organic mulches can be a promising option for biopesticidal control of liverwort and a component of integrated liverwort management.
... Canola weed suppressiveness can be optimised to reduce specific weed growth and reproduction through farming practices that allow the implementation of a variety of cultural techniques such as sowing crops with different planting dates to reduce other weed pressure [18]. In addition, the ability of crops to suppress weeds appears to be strongly variety-dependent [59][60][61]. ...
Canola (Brassica napus L.) is a profitable grain crop for Australian growers. However, weeds remain a major constraint for its production. Chemical herbicides are used for weed control, but this tactic also leads to the evolution of herbicide resistance in different weed species. The suppression of weeds by crop interference (competition and allelopathic) mechanisms has been receiving significant attention. Here, the weed suppressive ability and associated functional traits and stability of four selected canola genotypes (PAK85388-502, AV-OPAL, AV-GARNET, and BAROSSA) were examined at different locations in NSW, Australia. The results showed that there were significant effects of canola genotypes and of genotypes by crop density interaction on weed growth. Among the tested genotypes, PAK85388-502 and AV-OPAL were the most weed suppressive and, at a plant density of 10 plants/m2, they reduced the weed biomass of wild radish, shepherd’s purse, and annual ryegrass by more than 80%. No significant differences were found in the primary root lengths among canola varieties; however, plants of the most weed-suppressive genotype PAK8538-502 exhibited a 35% increase in lateral root number relative to plants of the less weed-suppressive genotype BAROSSA. The analysis of variance revealed a significant influence of genotypes with PAK85388-502 and AV-OPAL performing the best across all the research sites. Results showed that canola genotypes PAK85388-502 and AV-OPAL were more weed suppressive than AV-GARNET and BAROSSA and may release specific bioactive compounds in their surroundings to suppress neighboring weeds. This study provides valuable information that could be utilised in breeding programs to select weed-suppressive varieties of canola in Australia. Thus, lateral root number could be a potential target trait for weed-suppressive varieties. Additionally, other root architecture traits may contribute to the underground allelopathic interaction to provide a competitive advantage to the crop.
... Among these, 519 species are annual plants, while 322 species are perennial. Weeds are known for their resilience to unfavorable soil and climate conditions, allowing them to sprout before cultivated crops and absorb resources that are essential for crop growth [2,3]. The presence of weeds not only hinders the quality of field work but also leads to increased expenses for farmers. ...
Weeds are a major problem in agriculture, causing significant damage to crops and reducing yields. Effective weed control is essential to ensure the success of agricultural operations and maximize productivity. This article focuses on the effectiveness of chemical control methods against harmful weeds in crops such as Sarthamus tinctorius (safflower), Linum usitatissimum (flax), Solanum tuberosum (potato), and Cicer (chickpea). In addition to competing with crops for resources, weeds can also host pests and diseases that can damage crops. Some weeds, such as elderberry, kukmaraz, and kakra, produce toxic seeds that can be harmful to both humans and animals if ingested. Weeds can also clog irrigation channels and hinder the operation of agricultural machinery, leading to additional costs and inefficiencies in agricultural operations. Chemical control methods are commonly used to manage weeds in agriculture. Herbicides are chemicals that are specifically designed to kill or inhibit the growth of weeds. They can be applied to fields before planting to prevent weed growth or after planting to control existing weeds. Herbicides work by interfering with the metabolic processes of weeds, causing them to die or stop growing. The effectiveness of herbicides depends on several factors, including the type of weed, the stage of weed growth, environmental conditions, and the application method. It is important to select the right herbicide for the target weed species and to follow the recommended application rates and timing to achieve optimal results.
... Allelopathy refers to the process by which plants release biochemicals, known as allelochemicals, into the environment that can have inhibitory or stimulatory effects on neighboring organisms [69]. These crops can release allelochemicals that not only inhibit weed growth but also enhance soil microbial activity [70]. The specific mechanisms of action can vary widely, ranging from disruption of cell division to interference with photosynthesis or hormone regulation [71,72]. ...
Crop rotation and diversification (CRD) are crucial strategies in sustainable agriculture, offering multiple benefits to both farmers and the environment. By alternating crops or introducing diverse plant species, CRD practices improve soil fertility, reduce pest populations, and enhance nutrient availability. For example, legume-based rotations increase soil nitrogen levels through biological nitrogen fixation, reducing the need for synthetic fertilizers. Moreover, these practices promote more efficient water and nutrient use, reducing the reliance on synthetic fertilizers and minimizing the risk of pests and diseases. This review synthesizes findings from recent research on the role of CRD in enhancing sustainable agriculture and resilience, highlighting the potential contributions of these practices towards climate change mitigation and adaptation. Specific crop rotation systems, such as the cereal–legume rotation in temperate regions and the intercropping of maize with beans in tropical environments, are reviewed to provide a comprehensive understanding of their applicability in different agroecological contexts. The review also addresses the challenges related to implementing CRD practices, such as market demand and knowledge transfer, and suggests potential solutions to encourage broader adoption. Lastly, the potential environmental benefits, including carbon sequestration and reduced greenhouse gas emissions, are discussed, highlighting the role of CRD in building resilient agricultural systems. Collectively, this review paper emphasizes the importance of CRD methods as sustainable agricultural practices and provides key insights for researchers and farmers to effectively integrate these practices into farming systems.
... Synthetic herbicides are most widely used to control the interference of weeds. Although several pre and post-emergence herbicides are the commonly used option to manage the wild radish efficiently and quickly (Madafiglio et al. 2006), but consistent and heavy use of synthetic herbicides would create a number of human health problems, pollute the groundwater, disturb the soil ecosystem as well as increase the accumulation of harmful residues in food material (Jabran et al. 2015). Synthetic herbicides are one of the biggest hurdles while shifting from conventional chemical-based farming to organic farming (Barratt et al. 2018). ...
Wild radish is increasingly becoming a problematic and troublesome weed of cropping systems in Pakistan, and an environment-friendly solution for this rapidly spreading weed is inevitable. The aqueous extracts of herbal plants with a strong phytotoxic influence are supposed to be used for an eco-friendly management of this weed. So, various pharmaceutical plants locally available in Pakistan were explored for their allelopathic potential against seed germination and seedling growth of wild radish. In this regard, aqueous extracts of the Swertia chirata L., Citrullus colocynthis L., Populous trmuloides L., Aloe barbadensis miller L., Fumaria officinalis L., Sphaeranthus indicus L., Berberis aristata L., and Withania coagulans L. were prepared, and their phenolic compounds were identified. The aqueous solution of Sphaeranthus indicus L. showed a maximum decline in germination percentage (76%), germination index (62%), and germination energy (76%), causing a maximum delay (3 days) to complete 50% germination with the highest mean germination time (4.6 days) of wild radish as compared with distilled water treatment. The shoot length, root length, shoots dry weight, root dry weight, seedling biomass and seedling vigor index of wild radish were most inhibited by aqueous solutions of Citrullus colocynthis L. The highest electrolyte leakage of wild radish seedlings was also observed where aqueous extracts of Citrullus colocynthis L. were applied. The leachate of Aloe barbadensis miller L. was the second most inhibitor of germination and seedling growth of wild radish. The Populous trmuloides L. also ranked second regarding germination inhibition. In contrast, the aqueous extracts of Swertia chirata L. and Berberis aristata L. showed a reverse phenomenon and enhanced the germination. The Aqueous extracts of all other plants showed marginal results regarding germination and seedling growth inhibition and were statistically at par with control treatment. Furthermore, the highest concentration of phenolics was detected in Sphaeranthus indicus L. (2789 mg L-1), while the lowest was present in Withania coagulans L. (1093 mg L-1).
... Plants and microorganisms release allelochemicals to survive in the competition and as a natural defense mechanism against invasive plant species (Mattner 2006 ). The allelochemicals are introduced into the environment by (i) root exudation (Inderjit and Weston 2003 ), (ii) leaching, (iii) volatilization, and (iv) decomposing plant debris (Jabran et al. 2015 ). The biosynthesis of these allelochemicals depends upon the compound, plant type, age, and environmental conditions (Latif et al. 2017 ). ...
Weed infestation is one of the most damaging biotic factors to limit crop production by competing with the crop for space, water, and nutrients. Different conventional approaches are being used to cope with weed infestation including labor intensive manual removal and the use of soil-degrading and crop-damaging, and environment-deteriorating chemical herbicides. The use of chemicals for weed control has increased two-fold after the Green Revolution and their non-judicious use is posing serious threats to mankind, animals, and biodiversity. The detrimental effects of these approaches have shifted the researchers’ attention from the last two decades towards alternate, sustainable, and ecofriendly approaches to cope with weed infestation. The recent approaches of weed control including plant and microbial allelopathy have gained popularity during last decade. Farmers still use conventional methods, but the majority of farmers are very passionate about organic agriculture and describe it as a slogan in the developed world. The effectiveness of these approaches lies in host specificity by selective bacteria and differential response towards weeds and crops. Moreover, the crop growth promoting effect of microorganisms (allelopathic bacteria) possessing various growth promoting traits i.e., mineral solubilization, phytohormone production and beneficial enzymatic activity, provide additional benefits. The significance of this review lies in the provision of a comprehensive comparison of the conventional approaches along with their potential limitations with advanced/biological weed control approaches in sustainable production. In addition, the knowledge imparted about weed control will contribute to a better understanding of biological control methods.
... In addition, the synergistic effect between plants can be benefited by taking it into the appropriate agricultural rotation system (Bellostas et al., 2007;Jabran, 2017;Acar et al., 2019). Several studies showed the allelopathic potential of many plants of the cruciferous family and their efficiency in weed control (Uremis et al., 2009;Bangarwa et al., 2011;Jabran et al., 2015;Elsekran, 2022;Elsekran & Ustuner, 2024). It was reported that when the plant was incorporated into the soil, it inhibited weed biomass by 96% in subsequent potato production (Boydston & Hang, 1995). ...
This study aimed to evaluate the allelopathic effects of black radish and garden cress on johnsongrass in tomatoes under field and greenhouse conditions. In the field experiment, black radish and garden cress were grown as a pre-plant, then mixed with the soil and used with and without mulch against johnsongrass. The effects of these applications on johnsongrass development and tomato yield and quality were evaluated. Different concentrations of pre-plant extracts were also investigated on johnsongrass and tomato seedling growth in greenhouse conditions. The lowest johnsongrass density was recorded in black radish and garden cress with mulch (106.7 and 97.2 number m-2). Black radish and garden cress with mulch achieved johnsongrass control efficiency of 80.2 and 84.0% compared to those without mulch 56.8 and 58.2%. The effect of all treatments was positive in increasing the quantity and improving the quality of tomato production. The results of greenhouse experiments showed that high concentrations (10%) of black radish and garden cress extracts achieved high levels in preventing the germination and growth of johnsongrass. In these treatments, johnsongrass seeds and rhizomes germination rates were 17.5 and 7.5%, 20.0 and 12.5% respectively. GC-MS analysis showed that five ITCs were in black radish, and their total percentages were 40.4%. In the garden cress, it was found that there is only one ITC with a percentage of 61.0%. Black radish and garden cress inhibit the germination and growth of johnsongrass seeds and rhizomes very effectively. Sustainable management of johnsongrass can be achieved by introducing these plants into a crop rotation which may be an alternative or reduce the use of herbicides.
... Phalaris minor, Chenopodium album, Rumex dentatus and Convolvulus arvensis (Salawu et al., 2013). Among various allelopathic crops, sorghum is one of the most allelopathic one, that con tains allelochemicals like phenolic, alkaloids, flavonoids and terpeniods which suppresses the growth of weeds and increase the production of wheat (Jabran et al., 2015). Foliar application of sorghum water extracts reduced weed density and dry weight by 15 to 17% and 19 to 49%, respectively in sesame crop (Murimwa et al., 2019). ...
Background: Sorghum extract + ready-mix clodinafop + metsulfuron herbicide as post-emergence was most effective for broad spectrum weed management in wheat crop. Sorghum extract and herbicide combination increased the growth as well as yield of wheat. Weeds are a major challenge in wheat crop causing poor productivity. At a present time, maximum does of herbicides are used in wheat crop, but after some time their harmful effect are visible on crop and soil. so sorgoleone allelochemical are used with herbicide. this ecofriendly integrated approach reduce weed density and increase the productivity of wheat. Methods: The experiment was conducted to work out “Bio-efficacy of sorghum extract and herbicide on growth, yield and quality of wheat (Triticum aestivum L.).” The eleven treatment combination sorghum extract alone as well as combined with ready-mix of clodinafop + metsulfuron herbicide with weed free and weedy check was taken during experiment. The experiment was laid out in randomized block design (RBD) during rabi season of 2021-22 at Instructional Farm, College of Agriculture, Jodhpur (Rajasthan) India. Result: Sequential application of sorghum extract (1:3) + ready-mix of clodinafop + metsulfuron 64 g/ha was applied at 21 and 30 DAS, significantly increased plant population, plant height, tillers and SPAD chlorophyll meter reading (SCMR) of wheat. This treatment resulted in significantly higher grain yield 4543 kg/ha and magnitude of increments were 34.87% over weedy check and was comparable with sorghum extract (1:2) + ready-mix of clodinafop + metsulfuron 64 g/ha.
... Allelopathy has a pertinent significance for sustainable, ecological, and integrated weed management systems (Jabran et al., 2015). The advantages of allelochemicals lie in their versatility of not only being inhibitor of weed growth but also being eco-sustainable. ...
The productivity of major field crops is highly compromised due to weed infestation. Inefficient weed management practices and undue and excessive use of chemical herbicides have drastically contaminated the environment and human health, in addition to resistance development in weed species. Therefore, utilization of allelopathic plants to explore phytochemicals as potent organic alternatives to such chemical herbicides has become indispensable. The current study evaluates the comparative bio-herbicidal potential of methanolic extracts of castor (Ricinus communis), artemisia (Artemisia santolinifolia), wheat (Triticum aestivum), and sorghum (Sorghum bicolor) to suppress growth of major weeds, i.e., wild mustard (Sinapis arvensis), Italian ryegrass (Lolium multiflorum), and carrot grass (Parthenium hysterophorus). The results demonstrated a concentration-dependent effect on weeds’ growth. Overall, in vitro seed germination was reduced from 60 to 100% in response to 5% (w/v) extract concentration. Significant reduction in radicle length, hypocotyl length, and fresh biomass of the weeds was also observed. A strong inhibitory effect was seen in in vivo pot experiments, revealing that application of 10–20% methanolic extracts induced permanent wilting and substantial reduction in the chlorophyll content of weeds along with 20–80% increase in oxidative stress. Artemisia showed the most significant allelopathic effect, on account of highest phenolic and flavonoid contents, followed by castor, wheat, and sorghum, against S. arvensis, L. multiflorum, and P. hysterophorus, respectively. Phytochemical analysis, through high-performance liquid chromatography (HPLC), also exhibited a correlation between extract’s phytotoxicity and their antioxidant potential due to their major constituents (rutin, quercetin, catechin, gallic acid, vanillic acid, syringic acid, ferulic acid, p-hydroxy benzoic acid, p-coumaric acid, and sinapic acid), among the total of 13 identified in methanolic fractions. Comprehensive profiling of allelochemicals with liquid chromatography–mass spectrometry (LC-MS) determined 120, 113, 90, and 50 derivates of phenolic acids, flavonoids, and alkaloids, reported for the first time through this study, demonstrating significant allelopathic potential of the targeted plant fractions, which can be explored further to develop a sustainable bio-herbicidal formulation.
... This loss ranges between 30-50% and sometimes 70%, depending on the quality and density of those weeds [5]. The weed causes 34% of crop losses [6]. The use of amino acids, including glutamic acid, which is found in most plants. ...
A field experiment was carried out during the 2022-2023 agricultural season at the research station of the Field Crops Department - College of Agriculture - Tikrit University. It included 54 experimental units. Each experimental unit contained five lines of wheat, Triticum aestivum L., and weed seeds were planted between the wheat lines. The experiment was applied in a completely randomized block design (R.C.B.D), with three sectors, and the treatments were distributed in the arrangement of split plots. The treatments were spraying with glutamic acid during the three growth stages at three concentrations and two types of weeds ( Malva praviflora and Raphanus raphanistrum ). The results of the statistical analysis of the characteristics of the wheat crop showed a significant superiority in the comparison treatment (without weeds), and with a concentration of 0% glutamic, the highest germination rate for the three growth stages, as well as in the character of plant height, leaf area, total chlorophyll, number of shoots, and number of ears for the wheat crop.
... Allelopathy is existent widely in the natural plant communities (Lingorski and Churkova, 2011). The use of allelopathy principles and strategies, such as the use of allelopathic cultivars, intercropping with allelopathic weed suppressive plants, the use of allelopathic cover crops and residues, and rotational sowing of allelopathic crops can play an important role in achieving sustainable and integrated weed control (Jabran et al., 2015). The different type of allelochemicals are produced by different type of crop plants, weeds and microorganism through the different mechanism viz. ...
The analysis of a market's economy is known as microeconomics. When
the quantity demanded and the amount provided is equal in relation to the
price, the market for that commodity or service is said to be in equilibrium.
This precalculus-based essay gives a basic introduction of important
microeconomic concepts. It demonstrates how a market's demand and supply
curves are created by customer behavior and business decisions that aim to
maximize profits. Section 1 presents the introduction and uses of
microeconomics. Further section 2 represents some of the theories that define
well the concept of microeconomics. In Section 3 supply and demand model
has been specified, and characteristics of market equilibrium are examined
using graphical representations of the demand and supply functions. The
issues highlight what occurs at equilibrium when a per-item tax is imposed on
the provider and when the same tax is imposed on the buyer, which may
surprise some. In the last section, the concept of market structure has been
discussed thoroughly.
... Weeds in agricultural areas are one of the biggest problems in the world, as they lead to yield and product losses (Jabran et al. 2015). Around 1800 weed species in the world cause a 31.5% decline in agricultural productivity (Kubiak et al. 2022). ...
Field bindweed (Convolvulus arvensis L.) is an important weed species on agricultural areas in Türkiye and worldwide. The study was conducted in 2018-2019 and seeds from 16 different provinces in Türkiye (Adana, Ankara, Çanakkale, Denizli, Diyarbakır, Erzurum, Hatay, İzmir, Karaman, Kayseri, Konya, Malatya, Samsun, Şanlıurfa, Tekirdağ and Uşak) were collected and germinated under greenhouse conditions (19/29°C day/night) and molecular characterization of the samples was performed. As a result of comparing the samples with a specific reference from NCBI gene bank, it was found that the similarity ratios were close to each other but formed different groups. In the study, it was determined that the samples from Adana, Konya and Samsun belonged to different groups in terms of similarity. Then, the dose-response rates of these samples to 2,4-D, which is licensed against field bindweed, were determined. In the dose-response analysis of the herbicides, ED50 values of 131.93, 115.42 and 141.89 g.a.i/ha were determined for Adana, Konya and Samsun, respectively. As a result of the study, it was found that the dose-response of field bindweed in Adana, Konya and Samsun provinces, which belong to different molecular groups, to 2,4-D herbicides is close to each other but has different values.
... Release of compounds by invaders which suppress germination, growth, and/or reproduction of other species contributes toward invasion success in a number of cases (Kato-Noguchi 2020; Qu et al. 2021;Zhu et al. 2021;Kumar and Garkoti 2022). Different mechanisms are adopted by invasive plants in order to release these allelochemicals; such as through root exudation, leaching through areal parts, volatilization and by decomposition of leaves (Zamorano 2006;Jabran et al. 2015). These allelochemicals not only affect the community structure but also affect the ecosystem processes and its integrity (Callaway 2003;Grove et al 2012;Shackletion et al. 2015), they can serve as warning signals to alert neighboring plants of an imminent pathogen attack (Heil and Ton 2008) besides deterring herbivores, exhibiting direct antibacterial activities, and inhibiting growth of plant competitors (Effah et al. 2022). ...
For invasion biologists, the key question as to why only some alien species emerge as successful invaders as against a majority of other alien introduced species is still unclear. One of the best ways to resolve this question is to compare phylogenetically related alien invasive vs alien non-invasive species. Here we compared the allelopathic potential and phytochemical profiling of two congeneric species of Amaranthus (Amaranthus caudatus—invasive alien and non-invasive alien Amaranthus blitum. Petri dish bioassay followed by a pot experiment was used to evaluate the allelopathic effects of aqueous leaf and root extracts (1:10 w/v) of the said alien congeners on the germination and shoot length of Raphanus sativus. Petri dish bioassay results revealed that both species exhibited comparable levels of allelopathic activity; however, leaf extracts of both species showed significantly stronger inhibitory effects than root extracts, a trend corroborated by phenolic content assessments. However, no allelopathic effects on seed germination were observed in the pot culture bioassay. Comparative phytochemical profiling of these Amaranthus species, utilizing Gas Chromatography–Mass Spectrometry (GC–MS) and High-resolution liquid chromatography and mass spectrometry (HR-LC-MS) identified diverse array of compounds including methyl 8,9-octadecadienoate, n-hexadecanoic acid, phytol, loliolide, stigmasta-7,16-dien-3-ol, catechol borane, ellagic acid etc. which are known for their role in allelopathic interactions and invasiveness of the alien plants. Phytochemical analysis unveiled comparable levels of phytochemicals in both the invasive alien and non-invasive alien species of Amaranthus. In conclusion, our study revealed that while allelopathy may contribute to the invasiveness of the Amaranthus species, it does not seem to be a unique characteristic feature for the invasiveness of invasive alien species (Amaranthus caudatus) in comparison with its non-invasive alien congener. The present study recommends that more congeneric comparisons are needed to understand the role of high chemical diversity in alien plant invasions, and whether it is linked to the origin of the plant species.
... These residues are potentially capable of inhibiting the germination and growth of weeds in subsequent crops. However, in order to apply these nding in an integrated weed management system, more knowledge needed, especially about the effects in the eld experiments applications (Jabran et al., 2015). In the absence of data in this regard, it is still important to note that in the agricultural company, from which the coriander biomass was taken for this experimentation, the crops used in succession to coriander, have consistently shown reduced weed presence, with evident bene ts in terms of growth and yields (Bartocci, personal communication). ...
In recent years there has been increased interest about the allelopathic effects of plant extracts used as bioherbicides, in order to manage weeds with a decreasing use of herbicides. An interesting crop, from an allelopathic point of view, is coriander ( Coriandrum sativum L.), a medicinal plant member of Apiaceae family. The aim of this study was to evaluate the allelopathic activity of coriander against a possible succeeding crop, like wheat ( Triticum aestivum L.), and against some weeds, like Lolium multiflorum Lam., Sinapis alba L. and Amaranthus retroflexus L., ubiquitous in the Mediterranean agroecosystems. In Petri dish bioassays, seeds of above mentioned species were treated with 0, 2.5, 5, 10, 17.5, 25 % w/v concentrations of aqueous extracts from leaves, stems and roots of coriander at flowering and maturity growth stage. The ranking among different extracts based on their allelopathic effects was: leaves extract > stems extract > roots extract. The allelopathic activity of coriander at maturity stage decreased with respect to that at flowering stage. The aqueous extracts from aerial biomass of coriander inhibited the seed germination of weeds, but not that of T. aestivum . This research has provided interesting scientific insights into the allelopathic activity of coriander in weed management, however other aspects need to be further investigated.
... Harvesting of crops leaves behind the roots of old plants that are buried deep in the soil, which is considered the principal cause of crop autotoxicity due to the release of phenolic allelochemicals (Jabran et al., 2015;Liu et al., 2018). These phytotoxins directly distress the succeeding crops, alter the organic matter content of the soil, cause microbial imbalance, alter nutrient uptake and lead to immobilization and an increase in ion leakage (Okumu et al., 2019). ...
Allelopathy, a biological phenomenon involving the production and release of secondary metabolites known as allelochemicals, plays a critical role in plant interactions and agroecosystem dynamics. Phenolic compounds are a significant class of allelochemicals that profoundly affect plant competition, soil health, and microbial communities. When released into the soil, their action depends on the soil’s physico-chemical characteristics and microbial communities. This review comprehensively inspects phenolic allelochemicals’ structure-function relationship, their direct combat with root cells in the rhizosphere, ecological functions, and their role in plant succession and stress tolerance. Phenolic allelochemicals, characterized by their diverse structures and ecological roles, offer a sustainable alternative to synthetic herbicides due to their minimal residual impact on the environment and rapid biodegradation. Additionally, the review addresses the challenges and future directions in applying phenolic allelochemicals, aiming to bridge the gap between ecological theory and practical agricultural applications for environmental protection and crop productivity enhancement.
Producing compost, mulch, or organic fertilizers are suitable methods for utilizing pruning residues,
which are effective in reducing environmental problems caused by the accumulation of pruning
residues. Wood is a part of pruning residues that, due to decomposition and release of biochemical
compounds, have allelopathic effects. Since limited reports have been published regarding the
allelopathic effects of wood from trees and ornamental shrubs, in the current experiment, the
biochemical compounds and allelopathic effects of wood from eight species of ornamental trees and
shrubs were investigated. Pruned wood of Bougainvillea, Albizia lebbeck, Cordia myxa, Conocarpus,
Dodonaea viscosa, Nerium oleander, Leucaena leucocephala, and Callistemon citrinus was soaked in
water for 24 and 48 hours to prepare water elutes. The analysis of biochemical compounds showed
significant differences in the phenolic compounds, tannin index (A280), flavonoids, non-structural
soluble carbohydrates, total suspended solids, and electrical conductivity in the water elutes of wood
samples, but the pH of the water elutes did not show significant differences. The duration of soaking
wood in water (24 or 48 hours) affected the electrical conductivity and biochemical compounds in the
water elutes. The Leucaena leucocephala extract had the highest tannin index (67.10 A280/ml) and
soluble carbohydrates (81.1 mg/g), while the highest total phenol content was in Leucaena
leucocephala and Conocarpus (1.107 and 55.114 mg/g, respectively). The highest electrical
conductivity was in the Cordia myxa extract (87.2 ds/m), and the highest total suspended solids were
in the Callistemon citrinus extract (0.61%). The highest level of flavonoids was found in
Bougainvillea, Nerium oleander, Leucaena leucocephala, and Cordia myxa. The allelopathic effects
of the water elute prepared from wood samples resulted in a reduction in germination percentage and
germination index of cucumber seeds, as well as a decrease in the root and shoot length of cucumber
seedlings, indicating the presence of allelopathic effects of biochemical compounds present in the
wood of trees and ornamental shrubs. These results can be useful in selecting these species for
designing landscape plantings to their allelopathic effects of residues on neighboring grasses and
ornamental plants, or in managing pruning residues and producing compost or mulch from the wood
of ornamental trees and shrubs.
Türkiye'de ve dünyada önemli parazit bitkiler hakkında detaylı bilgiler verilmiştir. Parazit bitkilerin taksonomisi, biyolojisi, konakları, zararı ve mücadele yöntemleri....
4,8‐Dihydroxy‐1‐tetrahydronaphthone (4,8‐DHT), an allelochemical, was isolated from the Carya cathayensis epicarp and was discovered to have phytotoxicity in laboratory tests. In this study, field experiments were designed to assess the phytotoxicity of 4,8‐DHT on weeds in Cerasus yedoensis and Lagerstroemia indica forestlands after pre‐ and post‐emergence application, in addition to physiological effect on Lindernia procumbens were also measured. The phytotoxic results of 4,8‐DHT demonstrated that the total inhibition rate of weeds was 81.3% and 68.2% in C. yedoensis forestland and L. indica forestland after pre‐emergence applied for 24 days in 2021, and enhanced by 9.9% and 27.8% compared with post‐emergence treatment. Especially, in C. yedoensis forestland, a high concentration of 4,8‐DHT sprayed at the pre‐emergence stage after 8 days had a significant inhibition rate on all weeds except Cyperus rotundus , and was still above 80.0% after 24 days of exposure. Comprehensive control efficacy of 4,8‐DHT indicates that pre‐emergence application is more favorable for weeds control. Physiological analysis showed that 4,8‐DHT stimulated the contents of thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H 2 O 2 ), and proline and declined in the activities of antioxidant enzymes, meanwhile, accompanied by a decrease in the root vitality and chlorophyll content in L. procumbens . These results warrant further investigations of 4,8‐DHT applied in early pre‐emergence as a potential source of weed control agent.
Canola (Brassica napus L) is a profitable grain crop for Australian growers. However, weeds remain a major constraint for its production. Chemical herbicides are used for weed control, but this tactic also leads to the evolution of herbicide resistance in different weed species. Suppression of weeds by crop competition and allelopathic mechanisms has been receiving significant attention. Here, the weed suppressive ability, and associated functional traits and stability of four selected canola genotypes (PAK85388-502, AV-OPAL, AV-GARNET and BAROSSA) were examined at different locations of NSW, Australia. Results showed that there were significant effects of canola genotypes and of genotypes by crop density interaction on weed growth. Among the tested genotypes, PAK85388-502 and AV-OPAL were the most weed suppressive and, at plant density of 10 plants/m2, they reduced weed biomass of wild radish, shepherd’s purse and annual ryegrass by more than 80%. No significant differences were found in the primary root lengths among canola varieties; however, plants of the allelopathic genotype PAK8538-502 exhibited a 35% increase in lateral root number relative to plants of non-allelopathic genotype BAROSSA. The analysis of variance revealed a significant influence of genotypes with PAK85388-502 and AV-OPAL performed the best across all the research sites. Results showed that canola genotypes PAK85388-502 and AV-OPAL were more weed suppressive than AV-GARNET and BAROSSA and may release specific bioactive compounds in their surroundings to suppress neighbouring weeds. This study provides valuable information that could be utilised in breeding programs to select weed suppressive varieties of canola in Australia. Thus, lateral root number could be a potential target trait for weed suppressive varieties. Additionally, other root architecture traits may contribute to the underground allelopathic interaction to provide a competitive advantage to the crop.
In order to investigate the effect of pure Russian knapweed extract formulated with chitosan on the germination of pigweed (Amaranthus retroflexus), an experiment was conducted in 2016 in a factorial format based on a completely randomized design with three replications. The experimental treatments included the first factor of pure extract Russian knapweed and its formulated extract with chitosan and the second factor had seven concentrations (zero (Distilled water), 0.625, 1.25, 2.5, 5, 10, and 20% (gram of dry powder in a liter of distilled water)). The results showed that the interaction effects of the type of extract and different concentrations in the extract formulated with chitosan had the highest inhibition on the germination of the pigweed. Also, the highest plumule length, radicle length, and plumule fresh weight and radicle fresh weight were obtained from the treatment of 0.625% of pure extract and the lowest from the treatments of 5, 10, and 20% of formulated Russian knapweed extract with chitosan. The highest inhibition of plumule and radicle dry weight from concentrations of 5, 10, and 20% pure and formulated extract of Russian knapweed with chitosan (100% control compared to the distilled water), and the lowest inhibition was obtained from the concentration of 0.625% of the formulated extract with chitosan. It can be concluded from the results that with the increase in the concentration of the extract in the pure and formulated extract of Russian knapweed with chitosan, the percentage of germination and its related components decreases, but the effect of the formulated extract of Russian knapweed with chitosan compared to the pure extract in the concentrations of 0.625, 1.25 and 2.5% are higher.
Espanhol El manejo de malezas es fundamental para la eficiencia de las actividades humanas, con énfasis en la producción agrícola, ganadera y forestal. Pero además, las malezas también pueden afectar las actividades industriales, de transporte, la generación y producción de energía y la preservación y recuperación ambiental. Específicamente en áreas agrícolas, controlar las malezas sin afectar los cultivos es un gran desafío. Las comunidades de malezas son complejas y pueden contener docenas de especies. Los métodos de control deben ser suficientemente eficaces para las diversas especies de malezas presentes y seguros para los cultivos. Esta dificultad limita en gran medida el espectro de prácticas de control que pueden utilizarse eficazmente en áreas cultivadas. De todas las características de las malezas, la que se ha hecho más evidente en los últimos años es su capacidad de resistir el manejo. No sólo los herbicidas, sino todas las prácticas de control ya desarrolladas, incluida la cobertura del suelo y el cultivo mismo. En resumen, manejar las malezas de forma segura para los cultivos y el medio ambiente no es sencillo y requiere del uso articulado de conocimientos de química y bioquímica; genética; fisiología; edafología; medio ambiente; logística, tecnologías de aplicación y muchas otras áreas de conocimiento. El libro "Bases de la Ciencia de la Maleza", compuesto por trece capítulos desarrollados por profesionales con diferente titulación y reconocimiento, cumple esta misión y constituye una obra de referencia para estudiantes y profesionales. Los capítulos cubren prácticamente todos los aspectos relacionados con las malezas y su manejo. El texto está bien desarrollado conceptualmente, es equilibrado y fácil de leer, es decir, no es superficial en cuanto a los temas tratados, pero tampoco es prolijo en sus explicaciones. Finalmente, cabe destacar el hecho de que el libro se presenta en español y portugués, contribuyendo a la difusión, integración y estandarización del conocimiento sobre las malezas en toda América Latina. Portugues O manejo de plantas daninhas é fundamental para a eficiência das atividades humanas, com destaque para a agricultura, pecuária e produção florestal. Mas as plantas daninhas podem afetar, também, atividades industriais, de transportes, geração e produção de energia e a preservação e recuperação ambiental. Especificamente em áreas agrícolas, controlar plantas daninhas sem afetar as culturas é um grande desafio. As comunidades de plantas daninhas são complexas e podem conter dezenas de espécies. Os métodos de controle precisam ser suficientemente eficazes para as várias espécies presentes e seguros para as culturas. Essa dificuldade limita muito o espectro de práticas de controle que podem ser efetivamente utilizadas em áreas cultivadas. De todas as características de plantas daninhas, a que tem ficado mais evidente nos anos recentes é a capacidade de resistirem ao manejo. Não apenas aos herbicidas, mas a todas as práticas de controle já desenvolvidas, incluindo a cobertura do solo e a própria cultura. Em síntese, manejar plantas daninhas de modo seguro paras as culturas e para o ambiente não é simples e requer o uso articulado de conhecimentos de química e bioquímica; genética; fisiologia; solos; meio ambiente; logística, tecnologias de aplicação e de muitas outras áreas do conhecimento. O livro "Bases da Ciência das Plantas Daninhas", composto por treze capítulos desenvolvidos por profissionais de distintas qualificações e reconhecimento, alcança essa missão e constitui obra de referência para estudantes e profissionais. Os capítulos abrangem praticamente todos os aspectos relacionados às plantas daninhas e seu manejo. O texto é bem elaborado conceptualmente, equilibrado e de fácil leitura, ou seja, não é superficial nos temas discutidos, mas também não é prolixo nas explicações. Finalmente, merece destaque o fato de o livro ser apresentado em português e espanhol, contribuindo para a difusão, integração e uniformização dos conhecimentos sobre plantas daninhas em toda a América Latina.
The blister beetle Epicauta atomaria (Germar) (Coleoptera: Meloidae) is a phytophagous pest of various agricultural crops, especially in Amaranthaceae, Solanaceae, and Fabaceae. Currently, this insect is managed through the spraying of synthetic insecticides that cause serious human health and environmental damage. To reduce the use of synthetic insecticides, the integrated pest management (IPM) programs for other crop pests rely on the use of semiochemical compounds, such as pheromones, kairomones, and allomones, to manipulate the insects' behavior to prevent crop damage. However, studies on semiochemical compounds related to E. atomaria have never been carried out. For this reason, the aim of this study was to explore the chemical communication of E. atomaria . This includes the existence of (i) a sex and/or an aggregation pheromone, (ii) attractant volatile kairomones from host plants, and (iii) repellent volatile allomones from non‐host plants. Tests were carried out using olfactometers and an experimental arena. First, olfactometer tests failed to show the existence of volatile sex and/or aggregation pheromones of these insects. Second, olfactometer and experimental arena tests failed to demonstrate attraction of E. atomaria via volatile kairomonal compounds from host plants (chard, bell pepper, and cock's‐eggs). However, olfactometer tests showed that non‐host plants of E. atomaria (thyme and lavender) emit allomonal volatile compounds with repellent activity. This work represents a first step toward the elucidation of the chemical ecology of E. atomaria and suggests that volatiles from non‐host plants help shape the host preferences of these insects. Those volatiles could be used as a “push” component in a “push–pull” strategy against this pest.
Wheat allelopathy can be manipulated for sustainable weed management in wheat based cropping systems. Bioassays were conducted to quantify the allelopathic potential of 35 indigenous wheat genotypes against germination and seedling growth of wild oat (Avena fatua L.). Foliar application of aqueous extracts of wheat straw, surface mulching and incorporation of wheat straw of different genotypes were employed for bioassays study. Results revealed the suppressive allelopathic activity of different wheat genotypes manifested in the form of impaired germination and retarded seedling growth of wild oat. A highly significant genotypic variation in allelopathic potential was observed for different traits. Germination of wild oat was decreased by 10-84% over control by different wheat genotypes. Likewise, over 70% reductions in seedling root and shoot dry weight of wild oat was also observed in V6007. Wheat genotypes viz. V6007, AS 2000, V6111, V6034, V4611, V7189, Uqab 2000, Chanab 2000, Bhakkar 2002, Pak 81 and Rohtas 90 showed strongly inhibitory allelopathic activity against seedling growth of wild oat. V6007 exhibited highest suppression of wild oat. These studies confirm the suppressive allelopathic potential of indigenous wheat genotypes against wild oat that needs further to be explored under natural conditions.
Studies of new tools and methods for weed control have been motivated by increased consumer demand for organic produce, consumer and regulatory demands for a reduction in environmentally harmful herbicide use, and the decreased availability of farm workers willing to perform manual tasks, such as hand weeding. This study describes the performance of a new sprayer system for commercial production that integrates two herbicide applications in a single pass, selective herbicide (SH) application in narrow bands over the crop row, and a non-selective herbicide (NSH) application between crop rows. A real-time kinematic (RTK) global positioning system (UPS) was used for autoguidance in seeding and spraying operations. Conventional broadcast SHs and experimental treatments were applied at a constant nominal speed of 5.5 km h(-1) comparison. Trials in commercial sugar beet fields demonstrated the following: (i) average hand-weeding time can be reduced by 53% (ii) the new sprayer system reduced SH use by 76%, and (iii) sugar beet density did not change significantly during treatment. These results demonstrate the feasibility of using the new RTK-GPS controller sprayer system for differential and efficient herbicide application in inter- and intra-row zones in row crop production.
Weed management is a major concern for organic farmers. Strategies and techniques used by organic farmers vary according to crops, soils, climate and other factors. Organic farmers in upstate New York experienced in weed management were interviewed about what weed–crop complexes they face, how they manage weeds, and what priorities they have for research. The interviews were complemented with an all-day focus group conducted with the farmers who were interviewed. All of the farmers interviewed relied heavily on cultural practices, such as crop rotation, fertility management, high-density planting, transplants and the use of cover crops. Mechanical practices were also important for the farmers interviewed. They emphasized selection of the appropriate tools for the situation and techniques for using tools effectively. Most of the farmers interviewed relied on intensive tillage to control perennial weeds. Differences in practices were notable among the farmers interviewed. Several farmers shared innovations both in practices and equipment modification. Farmers identified soil and nutrient management; tillage and cultivation tools and practices; natural herbicides; flame weeding and no-till systems without herbicides as research priorities. Some of the topics suggested for research have already received substantial research attention; identification of these topics by the farmers indicated a need to disseminate research findings through extension materials and demonstration of viable practices.
Small-scale farmers are harshly suffering from high production costs, and so they permanently try to seek and apply the best cheap practices, bearing in mind that no yield losses occur. The objective of this work was to assess the possibility of lowering applied N rate in maize fields associated with less weeds infestation and keeping/boosting productivity. Thus, a field experiment was conducted to evaluate the response of maize yield and associated weeds to N levels (0, 144, 216, and 288 kg N ha−1) as well as maize (M)–cowpea (C) intercrops, sole-M, MC same ridge, MC alternating ridges, and sole-C. MC alternating ridges intercrop decreased weed biomass by 49.5% compared with sole-M. Sole-M was similar to MC alternating ridges intercrop in producing the maximum maize grain yield per hectare. In plots fertilized with 216 or 288 kg N ha−1, MC alternating ridges were statistically at par with sole-M for enhancing maize grain yield per hectare. Medium N application level (216 kg N ha−1) with MC alternating ridges showed the highest agronomic efficiency (14.6 kg kg−1). MC alternating ridges intercrop can save 26% of the cultivated land.
Reduced Herbicide Doses Used Together with Allelopathic Sorghum and Sunflower Water Extracts for Weed Control in Wheat
Water extracts from allelopathic crops possess the potential to control weeds effectively, especially when used in combination with reduced rates of herbicides. Label doses of different herbicides and their seventy percent reduced doses, were combined with 18 l/ha each of allelopathic sorghum and sunflower water extracts (WE). This combination was sprayed 30 days after sowing (DAS) for weed control in wheat ( Triticum aestivum ). Maximum reduction in total weed density and dry weight over the control, was recorded in a field sprayed with mesosulfuron + idosulfuron (Atlantis 3.6 WG) at 14.4 g active substance (a.s.)/ha. However, sorghum + sunflower WE each at 18 l/ha combined with doses which had been reduced by 70% of mesosulfuron + idosulfuron (Atlantis 12 EC at 36 g a.s./ha), or metribuzin + phenoxaprop (Bullet 38 SC at 57 g a.s./ha) or mesosulfuron + idosulfuron (Atlantis 3.6 WG at 4.32 g a.s./ha), reduced total weed dry weight by more than 90%, over the control. Sorghum and sunflower water extracts each at 18 l/ha combined with metribuzin + phenoxaprop (Bullet 38 SC at 57 g a.s./ha) produced a maximum number of productive tillers, spikelets per spike, number of grains per spike, biological yield and grain yield. Moreover, this treatment was the most economical along with having the maximum net benefits. The results suggested that weeds can be controlled in wheat, for a higher yield, when a 70% reduced herbicide dose is used in combination with allelopathic sorghum and sunflower water extracts.
Allelopathy is the process whereby an organic chemical (allelochemical) released from one plant influences the growth and development of other plants. Allelochemicals produced by specific rice (Oryza sativa L.) cultivars have potential to manage barnyard grass (Echinochloa crus-galli L.), a major yield-limiting weed species in rice production systems in Asia and North America. In this study, isolation and identification of an allelopathic compound, N-trans-cinnamoyltyramine (NTCT), in a Vietnamese rice cultivar 'OM 5930' was accomplished through bioassay-guided purification using reversed-phase liquid chromatography coupled with spectroscopic techniques, including tandem mass spectrometry, high resolution mass spectrometry, as well as one-dimensional and two-dimensional (1)H NMR and (13)C NMR spectroscopy. The identified compound, NTCT is considered a β-phenylethylamine. NTCT inhibited root and hypocotyl growth of cress (Lepidium sativum L.), barnyard grass and red sprangletop (Leptochloa chinensis L. Nees) at concentrations as low as 0.24μM. The ED50 (concentration required for 50% inhibition) of NTCT on barnyard grass root and hypocotyl elongation were 1.35 and 1.85μM, respectively. Results further demonstrated that mortality of barnyard grass and red sprangletop seedlings was >80% at a concentration of 2.4μM of NTCT. By 20days after transplanting, 0.425nmol of NTCT per OM 5930 rice seedling was released into the culture solution. With concentrations of 42μgg(-1) fresh weight, production of NTCT in intact rice plants can be considered high. These findings suggest that developing plants of Vietnamese rice cultivar OM 5930 release NTCT and may be utilized to suppress barnyard grass in rice fields. The potency of NTCT may encourage development of this compound as a bio-herbicide.
The effects of Chenopodium murale root exudates, applied as phytotoxic medias (PMs), were tested on Arabidopsis thaliana and Triticum aestivum. The effects of PMs, where wild-type roots (K), hairy roots derived from roots (R clones) or from cotyledons (C clones) were cultured, were different. K medium suppressed Arabidopsis germination, while other PMs reduced root and leaf elongation and the number of rosette leaves. R media were more phytotoxic than C media. Treatment of Arabidopsis with R8 down-regulated expression of core cell cycle genes: cyclin-dependent kinase (CDK) A1;1, four B-class CDKs, and cyclins CYCA3;1, CYCB2;4, CYCD4;2 and CYCH1 in root and shoot tips. Only CYCD2;1 transcript was elevated in treated shoots, but down-regulated in roots. Wheat Ta-CDC2 and Ta-CYCD2 genes showed the same expression profiles as their Arabidopsis counterparts, CDKA1;1 and CYCD2;1. PMs also caused increase of antioxidative enzyme activities in both plants. Exposure of Arabidopsis to PMs induced one catalase isoform, but repressed another, resulting in no net change of catalase activity. Wheat seedlings treated with PMs had catalase activity significantly elevated in all treatments, particularly in shoots. In both plants, PMs induced the activity of different peroxidase isozymes and total peroxidase activity. Both plants responded to phytotoxic treatments by induction of CuZn-superoxide dismutase. Thus, the phytotoxicity of C. murale root exudates is, at least partially, based on down-regulation of the cell cycle regulators and on generation of oxidative stress in the affected plants. We propose that C. murale root exudates should be considered as means of biological weed control.
Field experiments were conducted to compare the effects of allelopathic sorghum cultivars ‘Enkath’ and ‘Rabeh’ at three planting densities (6.6, 13.3 and 26.6 plant m−2) on weed growth and sorghum yields in 2009 and 2010. Sorghum planting densities suppressed average weed population by 26–42% and average weed biomass by 46–57% compared with weedy check in 2009. A similar trend in the reduction in weed population and weed biomass was observed in 2010. Planting densities at 6.6, 13.3 and 26.6 plant m−2 significantly suppressed average weed population by 26, 31 and 42% and average weed biomass by 88, 91 and 96% compared with weedy check, respectively, during 2009. A similar trend in effect was also recorded during 2010. Enkath cultivar reduced average weed density and dry biomass by 25 and 44% during 2009 and by 23 and 30% in 2010 compared with Rabeh cultivar. Root exudates of Enkath inhibited more weed growth than Rabeh. Increased planting density significantly increased average grain yield of sorghum. The highest grain yield of sorghum (12.68 t ha−1) was recorded in plots in which the planting density was 26.6 plant m−2.
Environmental pollution, development of herbicidal resistance among weeds and health hazards due to non judicious use of herbicides has forced the researchers to make concerted efforts to develop alternate weed control strategies. In that scenario, use of allelopathic plant water extracts with reduced rates of herbicides to control weeds in arable crops has become an attractive option for the researchers. The present study was conducted to investigate the possible effects of allelopathic plant water extracts in combination with reduced doses of atrazine for weed control in maize. Atrazine was applied @ full dose (500 g a.i. ha -1), ½ dose (250 g a.i. ha -1), ⅓ dose (167 g a.i. ha -1) and ¼ dose (125 g a.i. ha -1) alone; reduced doses (½, ⅓ and ¼) of herbicide were applied in combination with 20 L ha -1 of allelopathic plant water extracts of sorghum, brassica, sunflower and mulberry; 20 L ha -1 of allelopathic plant water extracts of sorghum, brassica, sunflower and mulberry was applied alone; while weedy check was also maintained as control. The four levels of atrazine showed 65-81% suppression of weeds density and weeds dry weight over control (weedy check), while allelopathic plant water extracts showed 70-75% suppression of weeds density and dry weight when used in combination with half and 1/3 rd dose of atrazine over control. Nonetheless, 49%, 36% and 31% more grain yield was obtained where full dose (alone) and half and ⅓ dose of atrazine in combination of allelopathic plant water extract were applied, respectively over control. In conclusion, allelopathic plant water extracts can be utilized with reduced doses of herbicide to keep environment healthy and efficient weed control in maize. Formulation of allelopathic water extracts into a handy product would facilitate their use for environment friendly weed management.
Background and Aims
Soil micro-circumstance and biological stress resistance were studied to validate our hypothesis that the allelopathic potential that was enhanced by breeding resulted partially from rhizophere microbes associated with the different varieties.
Methods
The rhizosphere soils from four wheat genotypes with different allelopathic potential were collected so as to compare their soil micro-environments and bio-pressure tolerances.
Results
The levels of these three categories such as bacteria, fungi, and actinomycetes ranged among 1.54–26.59 × 106, 0.43–4.12 × 104, and 1.36–18.25 × 105 CFU/g soil, respectively. Wheat 22 Xiaoyan with greater allelopathic potential had higher levels of microorganisms than the other three genotypes having weak allelopathy. The soil microbial carbon and nitrogen analyses suggested that wheat could create an active microhabitat with high activities of key soil enzymes such as urease, catalase, sucrase, and dehydrogenase. Using the approximate concentrations detected in wheat rhizosphere soils, the leachates of all four wheat materials significantly inhibited the growth of the weed Descurainia sophia and take-all pathogen Gaeumannomyces graminis var. Tritici.
Conclusions
Wheat exudates provided carbon and nitrogen resources for the relevant microorganism. Meanwhile, the rhizosphere soil microbes contributed to allelopathic potential of wheat by positive feedback.
To reduce the need for seasonal inputs, crop protection will have to be delivered via the seed and other planting material. Plant secondary metabolism can be harnessed for this purpose by new breeding technologies, genetic modification and companion cropping, the latter already on-farm in sub-Saharan Africa. Secondary metabolites offer the prospect of pest management as robust as that provided by current pesticides, for which many lead compounds were, or are currently deployed as, natural products. Evidence of success and promise is given for pest management in industrial and developing agriculture. Additionally, opportunities for solving wider problems of sustainable crop protection, and also production, are discussed.
Cover crop—based organic rotational no-till soybean production has attracted attention from farmers, researchers, and other agricultural professionals because of the ability of this new system to enhance soil conservation, reduce labor requirements, and decrease diesel fuel use compared to traditional organic production. This system is based on the use of cereal rye cover crops that are mechanically terminated with a roller-crimper to create in situ mulch that suppresses weeds and promotes soybean growth. In this paper, we report experiments that were conducted over the past decade in the eastern region of the United States on cover crop—based organic rotational no-till soybean production, and we outline current management strategies and future research needs. Our research has focused on maximizing cereal rye spring ground cover and biomass because of the crucial role this cover crop plays in weed suppression. Soil fertility and cereal rye sowing and termination timing affect biomass production, and these factors can be manipulated to achieve levels greater than 8,000 kg ha −1 , a threshold identified for consistent suppression of annual weeds. Manipulating cereal rye seeding rate and seeding method also influences ground cover and weed suppression. In general, weed suppression is species-specific, with early emerging summer annual weeds (e.g., common ragweed), high weed seed bank densities (e.g. > 10,000 seeds m −2 ), and perennial weeds (e.g., yellow nutsedge) posing the greatest challenges. Due to the challenges with maximizing cereal rye weed suppression potential, we have also found high-residue cultivation to significantly improve weed control. In addition to cover crop and weed management, we have made progress with planting equipment and planting density for establishing soybean into a thick cover crop residue. Our current and future research will focus on integrated multitactic weed management, cultivar selection, insect pest suppression, and nitrogen management as part of a systems approach to advancing this new production system. La producción orgánica de soya en sistemas de rotación con cero labranza basados en cultivos de cobertura, ha atraído la atención de productores, investigadores y otros profesionales agrícolas por la habilidad de este nuevo sistema de mejorar la conservación del suelo, reducir los requerimientos de mano de obra y disminuir el uso de combustible diesel en comparación con la producción orgánica tradicional. Este sistema está basado en el uso de centeno como cultivo de cobertura el cual es terminado mecánicamente con un rodillo de cuchillas para crear una cobertura de residuos in situ que suprime malezas y promueve el crecimiento de la soya. En este artículo, reportamos experimentos que fueron realizados durante la década pasada en la región este de los Estados Unidos sobre la producción orgánica de soya en sistemas de rotación con cero labranza basados en cultivos de cobertura, y delineamos las estrategias actuales de manejo y las necesidades futuras de investigación. Nuestra investigación se ha enfocado en maximizar la cobertura y la biomasa del centeno de primavera debido al papel crucial que este cultivo de cobertura juega en la supresión de malezas. La fertilidad del suelo y el momento de siembra y término del centeno afectan la producción de biomasa, y estos factores pueden ser manipulados para alcanzar niveles mayores a 8,000 kg ha −1 , el cual es el umbral identificado para la supresión consistente de malezas anuales. Manipular la densidad y métodos de siembra también influencia la cobertura del suelo y la supresión de malezas. En general, la supresión de malezas es específica a la especie, siendo las malezas anuales de verano que emergen temprano (e.g. Ambrosia artemisiifolia), los banco de semillas con altas densidades (e.g. > 10,000 semillas m −2 ), y las malezas perennes (e.g. Cyperus esculentus) los mayores retos. Debido a los retos de maximizar el potencial de supresión de malezas del centeno, hemos encontrado que el cultivar con altos residuos también puede mejorar el control de malezas significativamente. Adicionalmente al cultivo de cobertura y el manejo de malezas, hemos progresado con el equipo y la densidad de siembra para el establecimiento de la soya en capas gruesas de residuos de cultivos de cobertura. Nuestra investigación actual y futura se centrará en el manejo integrado de malezas multitáctico, la selección de cultivares, la supresión de plagas insectiles, y el manejo del nitrógeno como parte de un enfoque de sistemas para el avance de este nuevo sistema de producción.
The production of secondary metabolites and biomass of plants may be altered by coexistence and competition. Rice has coexisted with barnyardgrass in paddy systems for centuries and represents a model system for understanding plant–plant interactions. Despite increasing knowledge of allelochemicals produced and released by rice involved in coexistence of these two species, relatively little is known about the role and production of beneficial chemicals of rice in response to competing barnyardgrass. The purpose of this study was to quantify the growth-stimulating allantoin (5-ureidohydantoin) and its effect on barnyardgrass growth in a rice–barnyardgrass system. In this system, rice produced and released allantoin but barnyardgrass did not. The production of allantoin by rice responded to competition from barnyardgrass, and its concentration varied among rice cultivars tested. At 1:1 barnyardgrass and rice mixture proportion, allantoin concentration in allelopathic cultivars was obviously lowered by competing barnyardgrass, while no significant variation of allantoin concentration was observed in non-allelopathic cultivars. Barnyardgrass biomass was reduced in mixed-culture with rice cultivars, in particular, allelopathic cultivars. There was a positive relationship between allantoin concentration in rice cultivars and barnyardgrass biomass. Furthermore, allantoin stimulated the growth of barnyardgrass once released from rice or added to soil. The results suggest that rice plants of allelopathic cultivars appear to be able to detect the presence of competing barnyardgrass and respond by decreasing production of growth-stimulating allantoin, regulating the growth of barnyardgrass. In this manner, given rice cultivars may alleviate the competition of barnyardgrass and provide greater benefit to their own growth.
Wheat-derived foodstuffs represent about one-fifth of the calories consumed by humans worldwide. Bread wheat (Triticum aestivum L.) is one of the most important crops throughout the world, and it has been extensively studied for its allelopathic potential. In contrast, for allelopathy in durum wheat (Triticum turgidum ssp. durum), our knowledge is partial and fragmentary. Through highlighting recent advances in using allelopathy as a crop-breeding tool, we provide an overview of allelopathy in Triticum spp., to stimulate further coordinated breeding-oriented studies, to favor allelopathy exploitation for the sustainable cultivation of wheat, and in particular, to achieve improved biological weed control.
In Africa, yield loss and low income to farmers is exacerbated by pests and notorious weeds manifested in different cropping systems. The fact that crop species may be allelopathic to common weeds, pathogens and insect pests has attracted considerable attention as an alternative strategy for weed and pest management in small-scale and low-input mixed culture systems. The use of crop plants with greater allelochemical production could limit the need for agrochemicals and conventional herbicides for plant protection and defence. As a result, plant growth and grain yield will be increased, leading to greater profit margins for farmers. This review discusses the possible role(s) of allelopathy as a key player in protection, defence and growth stimulants in legume cereal intercropping systems.
Flaveria bidentis (L.) Kuntze is an alien species that is highly invasive in Hebei Province. An assessment of the influence of F. bidentis leaf residues on the growth of cotton (Gossypium herbaceum L.) seedlings and on soil fertility was carried out under controlled environmental conditions. Also, the concentrations of phenolics were determined in both F. bidentis residues and residue-amended soil. The results showed that the residues could significantly reduce height, root length and weight of cotton seedlings. The inhibitory effects increased gradually with increases in residue concentration. Peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) activity, as well as the concentration of malondialdehyde (MDA), also increased. POD and SOD activity were not significantly increased by 10 g kg of residues, but the differences were significant at 20 g kg of residues. Available K increased with increasing concentration of residues, whereas available P decreased, but the concentration of hydrolyzed N did not change in the soil. The concentration of phenolics also increased with increases in the residue concentration. It is concluded that F. bidentis residues adversely affect the early growth of cotton and have an impact on soil fertility by releasing water-soluble allelochemicals into the soil.
Grain legumes, such as peas (Pisum sativum L.), are known to be weak competitors against weeds when grown as the sole crop. In this study, the weed-suppression effect of pea–barley (Hordeum vulgare L.) intercropping compared to the respective sole crops was examined in organic field experiments across Western Europe (i.e., Denmark, the United Kingdom, France, Germany and Italy). Spring pea (P) and barley (B) were sown either as the sole crop, at the recommended plant density (P100 and B100, respectively), or in replacement (P50B50) or additive (P100B50) intercropping designs for three seasons (2003–2005). The weed biomass was three times higher under the pea sole crops than under both the intercrops and barley sole crops at maturity. The inclusion of joint experiments in several countries and various growing conditions showed that intercrops maintain a highly asymmetric competition over weeds, regardless of the particular weed infestation (species and productivity), the crop biomass or the soil nitrogen availability. The intercropping weed suppression was highly resilient, whereas the weed suppression in pea sole crops was lower and more variable. The pea–barley intercrops exhibited high levels of weed suppression, even with a low percentage of barley in the total biomass. Despite a reduced leaf area in the case of a low soil N availability, the barley sole crops and intercrops displayed high weed suppression, probably because of their strong competitive capability to absorb soil N. Higher soil N availabilities entailed increased leaf areas and competitive ability for light, which contributed to the overall competitive ability against weeds for all of the treatments. The contribution of the weeds in the total dry matter and soil N acquisition was higher in the pea sole crop than in the other treatments, in spite of the higher leaf areas in the pea crops.
Rotation systems and allelopathic interactions between plants-plants, plants-insects, plants-microorganisms would be important to exploit allelopathy in optimising the production of rotation systems. The objective of this study is to provide evidences for the importance of allelopathy in crop rotation for weed, insect and disease management with minimal application of external inputs. The relationships between allelochemicals and environmental factors are a key for the growth of plants under rotation. Examples from field crops, forage crops, horticultural species, weeds, and microbes provide evidences for the role allelopathy plays in crop rotation systems. In conclusion, the selection of certain plant sequences under standard environmental conditions may lead to suppression of weeds, insects and diseases and avoid yield decline.
The exploitation of crop allelopathy against weeds may be useful to reduce issues related to the use of herbicides. Several crops, such as alfalfa, barley, black mustard, buckwheat, rice, sorghum, sunflower and wheat, demonstrate strong weed suppression ability, either by exuding allelochemical compounds from living plant parts or from decomposing residues. As well as the positive effect on weed reduction, the introduction in agronomic rotations of allelopathic crops, their use as a mulch to smother crops or as a green manure may also be helpful in reduction of other agricultural problems, such as environmental pollution, use of unsafe products and human health concerns, through a reduction in chemical inputs. Knowledge of allelopathic properties of crops may also be advantageous in mitigation of soil sickness. Moreover, information on weed allelopathy may be profitable in preventing serious crop damage if the weed biomass is buried in the soil, and a crop susceptible to allellochemicals is planned for the following year. The use of allelopathic traits from crops or cultivars with important weed inhibition qualities, together with common weed control strategies, can play an important role in the establishment of sustainable agriculture.
Fundamentals of Weed Science, Fifth Edition, provides the latest information on this constantly advancing area of study. Placing weed management in the largest context of weed research and science, the book presents the latest advances in the role, control and potential uses of weed plants. From the emergence and genetic foundation of weeds, to the latest means of control and environmental impact, the book uses an ecological framework to explore the role of responsible and effective weed control in agriculture. In addition, users will find discussions of related areas where research is needed for additional understanding. Explored topics include the roles of culture, economics and politics in weed management, all areas that enable scientists and students to further understand the larger effects on society. Completely revised with 35% new content Contains expanded coverage of ethnobotany, the specific identity and role of invasive weed species, organic agriculture, and herbicide resistance in GM crops Includes an emphasis on herbicide resistance and molecular biology, both of which have come to dominate weed science research Covers all traditional aspects of weed science as well as current research Provides broad coverage, including relevant related subjects like weed ecology and weed population genetics.
The allelopathic impact of aqueous extract of 2 weeds Malva parviflora and Chenopodium murale on growth and photosynthesis of barley was investigated. The barley plants were sown in plastic pots containing a compost:sand mixture and placed in growth chambers. Plants were treated with the following weed aqueous extract concentrations; 0%, 25%, 50%, 75% and 100%. Different responses of plants to the two weeds were observed. Plant heights, number of leaves, number of tillers, root dry weight were not affected by M. parviflora. A clear effect of C. murale was recorded on the growth parameters; plant height, number of leaves and number of tillers, root fresh and dry weight. M. parviflora affected leaf growth, measured as leaf fresh weight (LFW), leaf dry weight (LDW) and leaf area. All the growth parameters measured were more adversely affected by C. murale than by M. parviflora. Significant effect at 25% and 50% and highly significant effect at 75% and 100% were recorded. The only concentration of M. parviflora that affected chlorophyll content was 100%, while the effect of C. murale was significant at 50% and highly significant at 75% and 100%. Photosynthesis was also inhibited by the two weeds, with more effect being with C. murale compared with M. parviflora.
Many organic and conventional producers rank weed control as their number one production cost. For organic producers particularly, weed control has become increasingly important as organic production has increased its market share. In conventional systems, herbicide resistance, off-target movement, and increased regulations have left many growers with few alternatives. Added to this is an increasing demand from the public for a safer and more sustainable supply of food. This chapter addresses the problems of mechanized agricultural systems to set the stage for the introduction and adoption of more advanced technology to meet the needs of growers and satisfy the desires of consumers.
Grower adoption of no-tillage (NT) approaches to organic soybean production has been limited, in part because of the perceived risks of ineffective cover crop management and lack of season-long weed suppression. We conducted research in 2008 and 2009 to assess those risks by quantifying the effects of winter rye cover-crop management (tilling, crimping, or mowing), soybean planting date (mid May or early June), and row width (19 or 76 cm) on weed recruitment, emergence patterns, season-long suppression, and late-season weed community composition in transitional organic production systems. The weed plant community consisted largely of summer annual species in each year, with velvetleaf or common lambsquarters as the most abundant species. Seedling recruitment from the soil seedbank varied between years, but velvetleaf recruitment was consistently greater in the tilled rye than in the NT rye treatments. Weed emergence tended to peak early in the season in the tilled rye treatment, but in the NT rye treatments, the peak occurred in mid or late season. More-diverse summer annual and perennial species were associated with the NT rye treatments. Even so, weed suppression (as measured by late-season weed shoot mass) was much greater in crimped or mowed rye NT treatments than it was in the tilled treatment. Weed suppression among NT rye treatments was greater in 19-than in 76-row spacing treatments in each year and was greater for mid May than it was for early June planted soybean in 2009. The NT planting of soybean into standing rye before termination (crimping or mowing) facilitated timely planting of soybean, as well as effective, season-long weed suppression, suggesting that those approaches to rye and weed management are of less risk than those typically perceived by growers. Our results suggest that NT systems in winter rye provide effective weed-management alternatives to the typical tillage-intensive approach for organic soybean production.
There is an increasing interest in the use of cover crops in agriculture, in Sweden mainly for the use as catch crops to reduce nitrogen leakage. Some of these crops are known for their allelopathic abilities, which may play a role in the control of weeds and contribute to reduced herbicide use. This study aimed to explore the possible suppressive effect of the cover crop species white mustard, fodder radish, rye, and annual ryegrass on the early growth of the weed species silky windgrass, shepherd's-purse, and scentless false mayweed. In a greenhouse experiment using fresh cover crop residues, white mustard was the only crop that showed an effect. It reduced both seedling establishment, by 51 to 73%, and biomass, by 59 to 86%, of shepherd's-purse and scentless false mayweed. In contrast, in a growth chamber experiment using frozen material, mean germination time of silky windgrass was extended by 20 to 66% by all cover crops. Also, three out of four cover crops reduced root growth in scentless false mayweed by 40 to 46%, and two out of four cover crops reduced root growth in shepherd's-purse by 13 to 61%. However, considering seedling survival, white mustard was the most prominent cover crop, reducing survival by 21 to 57% in shepherd's-purse and scentless false mayweed. In this paper we provide evidence that different weed species show different response to different cover crops under climatic conditions prevailing in Scandinavia. Such results emphasize the importance of understanding weed cover crop interactions as necessary for developing cropping systems that can utilize cover crops to suppress local weed flora.
Conventional soil management systems (SMS) use synthetic inputs to maximize crop productivity, which leads to environmental degradation. Organic SMS is an alternative that is claimed to prevent or mitigate such negative environmental impacts. Vegetable production systems rely on frequent tillage to prepare beds and manage weeds, and are also characterized by little crop residue input. The use of crop residues and organic fertilizers may counteract the negative impacts of intensive vegetable production. To test this hypothesis, we evaluated the effect of sweet corn (Zea mays L. var. rugosa) residue incorporation in a corn-cabbage (Brassica oleracea L.) rotation on crop yields, nutrient uptake, weed biomass and soil nutrients for organic and conventional SMS in two contrasting soil types (a Chromosol and a Vertosol). Yields of corn and cabbage under the organic SMS were not lower than the conventional SMS, possibly due to the equivalent N, P and K nutrients applied. Macro-nutrient uptake between the organic and conventional SMS did not differ for cabbage heads. Corn residue incorporation reduced the average in-crop weed biomass in