Abundant Weed Research Articles

Crassocephalum crepidioides as a sustainable protein supplement in Chocolatemahseer (Neolissochilus hexagonolepis) diets: Implications for growth,health, and economic viability in sustainable aquaculture

This study investigated the potential of Crassocephalum crepidioides, an abundant weed as a protein supplement in chocolate mahseer (Neolissochilus hexagonolepis) diets. The plant replaced a combination of fish meal and mustard oil cake at 0%, 25%, 50%, 75%, and 100% in experimental diets. A 12-week feeding trial was conducted to assess growth performance, survival, biomass yield, digestive enzyme activity, blood parameters, and economic viability. Results indicated that C. crepidioides can effectively replace up to 61.3% of the combined fish meal and mustard oil cake protein without negatively impacting fish health or growth, while reducing feed costs. Fish fed diets with 25% replacement showed improved weight gain (15.5±0.7 g) and biomass yield (6.05±0.25 kg/m³) compared to the control (14.6±0.8 g and 5.75±0.28 kg/m³, respectively). Survival rates were high across all treatments (94.0- 97.3%). Digestive enzyme activities and blood parameters remained within normal ranges for inclusion levels up to 75%. Economic analysis revealed potential cost savings of up to 15.5% when incorporating C. crepidioides into mahseer diets. This finding presents an opportunity to develop low-cost fish feed for resource-poor farmers in Meghalaya, effectively converting a local weed into a valuable aquaculture input, with broader implications for sustainable aquaculture practices globally.

Assessing the potential of fedaleh (Echinophora cinerea) essential oils as a natural herbicide for spring-summer crops

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.

From invasive species to bio-based composites: Utilizing water hyacinth for sound absorption and insulation

This study evaluates the acoustic properties of water hyacinth fiber composites, a notorious invasive species, focusing on their effectiveness as sound absorbers and insulators. By converting this abundant weed into bio-based materials, the research presents a promising eco-friendly alternative for acoustic applications. By examining a range of densities from 118 to 282 kg/m³, the study identifies how density impacts the Sound Absorption Coefficient (SAC) and Transmission Loss (TL). Notably, the sample with a density of 118 kg/m³ exhibited the highest Sound Absorption Average (SAA) at 0.63, while the densest sample at 282 kg/m³ achieved the highest Transmission Loss Average (TLA) at 32.5 dB, illustrating a direct correlation between increased density and enhanced TL, alongside a decrease in SAC. Statistical models obtained from the analysis of variance (ANOVA), semi-phenomenological model (Johnson-Champoux-Allard (JCA) model), and empirical model (based on the Delany-Bazley model) have been developed to predict the sound absorption and sound insulation performance of water hyacinth. These models demonstrate average errors of 0.0300, 0.0346, and 0.0377, respectively, significantly outperforming established models like the Delany-Bazley and Garai-Pompoli models in predicting the sound absorption average of water hyacinth bio-based composites. These models can be used to predict the acoustic properties of the composites, assisting in tailoring the composites to match specific applications. This approach leverages the natural abundance of water hyacinth to develop environmentally friendly acoustic materials, offering a sustainable solution to invasive species management and material development.

Influence of transplanting date and integrated weed management in system of rice intensification of aromatic black rice (Oryza sativa)

A field experiment was conducted during rainy seasons (kharif) of 2019 and 2020 at the research farm of School of Agricultural Sciences, Nagaland University, Nagaland to study the effect of transplanting date and weed management practices on productivity and profitability of aromatic black rice (Oryza sativa L.) under system of rice intensification. The experiment was conducted in a split plot design (SPD) with 3 transplanting dates (D1, 15th June; D2, 30th June; and D3, 15th July) in main plot and 5 weed managements practices [W1, Weedy check; W2, Conoweeding at 20 and 40 DAT (days after transplanting); W3, Pretilachlor @0.75 kg/ha (PE) fb hand weeding (HW) at 40 DAT; W4, Pretilachlor @0.75 kg/ha (PE) fb conoweeder at 40 DAT; and W5, Pretilachlor at 0.75 kg/ha (PE) fb bispyribac-sodium @ 25 g/ha (PoE)] in sub-plot, replicated thrice. Results showed that the most abundant weed flora observed in the experimental field were Fimbristylis quinquangularis (Vahl) Kunth, Cyperus esculentus (L.), Cyperus iria (L.), Rhynchospora colorata (L.) H.Pfeiff., Ludwigia linifolia Poir, Mimosa pudica (L.), Mimosa diplotricha Sauvalle, Scoparia dulcis (L.) and Eriochloa villosa (Thunb.) Kunth. Transplanting on 15th June recorded highest growth and yield of black rice. The improvement in the grain yield was about 39% under 15th June over 15th July transplanting date. Among weed management practices, pretilachlor @0.75 kg/ha at 3 DAT fb HW at 40 DAT recorded minimum density of weeds resulting in higher growth attributes and yield of black rice. Economic analysis showed that highest benefit cost (B:C) ratio was obtained when black rice was transplanted on 15th June along with application of pretilachlor @0.75 kg/ha at 3 DAT fb bispyribac-sodium @25 g/ha at 20 DAT and demonstrated to be the best treatment for profitable production of black rice under system of rice intensification.

EFFECT OF ETHANOL-WATER CONCENTRATION AS EXTRACTION SOLVENT ON ANTIOXIDANT ACTIVITY OF Acalypha indica

Acalypha indica is an abundant and obtainable wild weed plant in Indonesia. This is a possible opportunity to enhance its utility. The effect of free radicals is one of the factors that contribute to oxidative stress in the body, which can lead to cell damage and trigger various diseases. Plants rich in antioxidants can inhibit free radical reactions and protect the body from oxidative stress. In this study, we conducted the identification of major metabolite compounds using UHPLC-Q-Orbitrap HRMS from 70% ethanol extracts of Acalypha indica. We also performed phytochemical and antioxidant activity tests with various concentrations of ethanol-water solvents including water, 30%, 50%, 70% ethanol, and absolute ethanol to determine the optimal extraction conditions and the influence of solvent concentration on the antioxidant activity of Acalypha indica extract. The results of UHPLC-Q-Orbitrap HRMS identification showed that the 70% ethanol extract of Acalypha indica contains 10 major compounds suspected to correlate with its antioxidant activity. These include five flavonoids compounds (palasitrin, vitexin 2"-o-p-coumarate, isorhamnetin 3- (3",6"-di-p-coumarylglucoside), peucenin, and sulfuretin), two amino acid compounds (2-amino-3-carboxymuconic acid semialdehyde and N-Acetyl-L-phenylalanine), two carboxylic acid compound (citric acid and traumatic acid), and one phenolic compound (quinic acid). Phytochemical tests show positive results for flavonoids, tannins, alkaloids, and triterpenoids in each of water, 30%, 50%, 70% ethanol, and absolute ethanol extracts. The best antioxidant activity was obtained from the 70% ethanol extract with an IC50 value of 47.064 ppm, categorizing it as an extremely strong antioxidant.

Effect of Weed Growth on the Incidence of Sucking Pests in Cucumber

Field experiments were conducted in Fayoum Governorate to evaluate the impact of weeds growing in cucumber fields on the incidence of sucking pests viz., Aphis gossypii (Glover), Bemisia tabaci (Gennadius), Nezara viridula (L.), Phenacoccus solenopsis (Tinsley), Thrips tabaci (Lindeman), Myzus persicae (Sulzer), Empoasca decedens (Paoli) and Empoasca decipiens (Paoli) during 2018 and 2019 Neglected cucumber fields, with a high density of weeds, were observed to harbour more pests 57.7 and 55.9%, respectively. Meanwhile, the cucumber free-weedy field hosted the lowest rate of occurrence for all insect pests represented by 42.3 and 44.1%, respectively. Neglected fields with abundant weeds provide a favourable habitat, leading to increased incidence. Understanding the relationship between weeds and pests is crucial for developing effective IPM strategies in cucumber.

A Green Approach to Valorizing Abundant Aquatic Weeds for Nutrient-Rich Edible Paper Sheets Production in Bangladesh

The rapid and unprecedented expansion of the global population highlights concerns about the sufficiency of food resources to sustain this growth. This study investigates and substantiates the feasibility of renewable food resources in order to meet the nutritional requirements of consumers. Three edible aquatic weeds, helencha (Enhydra fluctuans), malancha (Alternanthera philoxeroides), and kalmi (Ipomoea aquatica), were used to produce edible paper sheets. The composition of the raw aquatic weeds and paper sheet samples was analyzed, including the proximate composition, amino acid content, minerals and heavy metal contents, and bioactive compounds. The dried raw aquatic weeds and paper sheets showed similar proximate compositions, with carbohydrates being the highest component (50.38–64.63%), followed by crude protein (15.25–19.13%), ash (9.30–15.88%), and lipid (1.55–3.43%). The raw weeds and paper sheets were rich in essential minerals like Na, Ca, and Zn with contents ranging from 27.7 mg/100 g to 30.4 mg/100 g, 126.8 mg/100 g to 489.65 mg/100 g, and 4.5 mg/100 g to 16.3 mg/100 g, respectively. Acceptable levels of heavy metals, including Ni, Pb, and Cu, were found. The paper sheets contained seven essential and eight non-essential amino acids. Among the essential amino acids, the phenylalanine content was the highest at 2735.9 mg/100 g in E. fluctuans paper sheets, followed by methionine at 2377.29 mg/100 g in the raw E. fluctuans and histidine at 1972.6 mg/100 g in E. fluctuans paper sheets. A. philoxeroides sheets showed the highest total amino acid content (16,146.81 mg/100 g), while I. aquatica showed the lowest (13,118.67 mg/100 g). The aquatic weed paper sheets were rich in bioactive compounds, and the numbers in E. fluctuans, A. philoxeroides, and I. aquatica paper sheets were 31, 33, and 40, respectively. There were no significant changes in the nutritional content of the aquatic weeds in paper sheet form compared with the raw weeds, which suggests promising prospects for their production and consumption as a source of nutrition and bioactive compounds.

Assessment of Some Leguminous Weeds as Potential Green Manure Crops under Mizoram, North East India

Background: This study aimed to evaluate the growth performance, biomass production and nutrient accumulation of three abundant leguminous weeds, namely Crotolaria micans Link., Aeschynomene indica L. and Calopogonium mucunoides Desv., found in Mizoram, India, to assess their potentiality as green manure crops. Methods: The field experiment was conducted using a randomized block design. After 90 days of sowing, the growth performance of the plants and biomass accumulation was assessed. Accumulation of nutrients was estimated by analyzing the nutrient content using standard methods and multiplying it with dry biomass. Result: The result revealed that Crotolaria micans showed higher growth and biomass accumulation. C. micans accumulates higher N, P, K, Zn, Cu and Fe contents in the shoot and root biomass while A. indica accumulates higher Ca in the root biomass. We conclude that Crotolaria micans was the most promising leguminous weed species in terms of growth performance, biomass production and nutrient accumulation and has better potential to be utilized as a green manure crop.

Preparation of sustainable and binder-free electrode materials for high energy asymmetric supercapacitor applications: A cleaner alternative

Herein, we demonstrate a pioneering method for repurposing one of the most abundant and noxious weeds (Parthenium hysterophorus or PH) derived ultrahigh surface area carbon as capacitive electrode and design high performance asymmetric supercapacitor with leveraging ternary metal oxides (TMO) (Ni–Co–Mn–O or TMO-1 and Ni–Co–Zn–O or TMO-2) as binder-free pseudocapacitive positive electrodes to improve the performance and efficiency of supercapacitors. Furthermore, the ternary metal oxides (TMO-1 and TMO-2) were synthesized using a one-pot hydrothermal method, followed by annealing. In a three-electrode configuration, both TMO-1 and TMO-2 exhibited remarkable capacitances. At a current density of 0.5 A/g, a total stored charge of 557.23 C/g and 628.22 C/g was obtained for the TMO-1 and TMO-2, respectively. The asymmetric construction using PH-900-K as the negative electrode and TMO-1 or TMO-2 as the positive electrode demonstrated a maximum energy density of 49.29 Wh/kg for the TMO-1//PH-900-K configuration. While the TMO-2//PH-900-K configuration exhibited a maximum energy density of 70.86 Wh/kg.

Intraspecific functional trait variation in weeds: A strategy in response to competition with crop and weed plants

AbstractWeeds are a key component of agroecosystems and compete with crop plants. Crop‐weed competition has been widely investigated over the past decades, although how functional traits mediate these competitive interactions has rarely been explored. In this study, we measured functional traits in 4400 individual plants belonging to 32 weed species, growing among four crops differing in functional traits. We assessed the intraspecific variation in weed functional traits in response to competition with crops but also with the other weeds. We found that the most abundant weeds have a lower intraspecific trait variability than other weed species for leaf dry matter content (LDMC), but this pattern was not observed for canopy height (CH) nor for specific leaf area (SLA). We found that most of the weed species tended to grow taller and have higher LDMC values when crop CH and LDMC increased. We propose that these species display a ‘crop matching’ strategy, tending to match crop functional trait values in response to competition. We also found that weed‐weed competition affected weed functional traits, sometimes more strongly than crop‐weed competition. This study highlights that intraspecific trait variation is important to consider when investigating the processes underlying weed species community assembly, especially resource competition. Further studies are required to identify the source of intraspecific trait variation in weeds and the consequences for weed fitness.

Alley cropping agroforestry systems change weed community composition and reduce dominant weed species associated with corn in southern Mexico

Alley cropping systems can change the weed community composition and reduce common weed species. However, it is unclear how different woody species intercalated with corn can affect weed abundance and community structure and corn yield in the tropics. The present study examined weed species diversity and community composition in alley cropping systems with three woody species associated with corn: Leucaena leucocephala (Lam.) de Wit, Guazuma ulmifolia Lam., and Moringa oleifera Lam. independently, and corn monoculture, as a control. The tree most dominant weed species were Ruellia nudiflora (Engelm. & A. Gray) Urb., Cynodon dactylon (L.) Pers., and Portulaca pilosa L. Our results showed that the alley cropping system compared with corn monoculture reduced the densities of common abundant weed species, changed weed community composition, maintained or increased plant diversity, but did not affect grain yield (t/h). Based on the sample completeness profile we found that Leucaena associated with corn had a higher weed diversity of order q = 1 and 2 (Shannon and Simpson index) and showed higher evenness compared with corn monoculture, which showed the lowest evenness of all treatments. We found nine weed species that only grow in alley cropping systems and Waltheria americana L., Momordica charantia L. and Porophyllum punctatum (Mill) S.F. Blake. with higher densities. Our findings support the hypothesis that alley cropping systems not only changes weed community composition, but also favours biodiversity conservation without reducing corn yield.

First Report of Colletotrichum truncatum Causing Anthracnose of Green Foxtail (Setaria viridis) in China.

Green foxtail (Setaria viridis (L.) Beauv.), belonging to the family Gramineae, is a monocotyledonous plant that is distributed in tropical and subtropical regions of the world. S. viridis is one of the most abundant weeds in corn, soybean, rice and other major crops in China, which competes with crops for light, moisture and nutrients, leading to yield losses. In September 2021, an unknown leaf spot disease was observed on the leaves of S. viridis in many greenhouses of Xinkou town, Xiqing district, Tianjin, China (116.95729, 39.09088), under cloudy and high humid conditions after a week of rain. Over 60% of the weeds were observed with leaf spots in 28 greenhouses of XinKou town. The characteristics of the disease were observed and investigated. Initial symptoms were brown spots of 1 to 5 mms, longitudinal elliptic, round, or spindle-shaped lesions on leaves of S. viridis. These spots continued to spread shortly after the onset of the symptoms. At the late-stage disease, the spots' edges were dark brown and irregular. Eventually, the center of the spots turned grayish-white and became thinner and drier until fracture. To investigate the disease, symptomatic weed leaves were separated and small patches with infected spots were cut out. Diseased tissues (3×3 mm) were disinfected with 75% alcohol for 30s  35s, rinsed three times with sterile distilled water and then placed on potato dextrose agar (PDA) at 25°C with a 12-h photoperiod for 7 days in incubators (RXZ-280C, Ningbo, China). With the pathogen growing on the PDA, three mycelia with uniform morphology were observed, which were named SVCT-01, SVCT-02, and SVCT-03, respectively. These mycelia were transferred and cultured for daily observation. The color of these mycelia on PDA appeared gray at first, which eventually turned to grayish black with numerous black microsclerotia, setae, and a few aerial mycelia after 7 days. The setae were 75 to 120 ×3.5 to 5 μm, with elliptic to claviform appressoria. Conidia were hyaline, falcate, unicellular, 16 to 25 × 2.6 to 3.8 μm (n=50). All characteristics of isolates were consistent with the description of Colletotrichum truncatum (Sutton, 1992). Pathogenicity testing was conducted on 3-leaves-stage S. viridis seedlings. Conidial suspension (106 conidia/mL) of isolates were sprayed on 20 S. viridis seedlings with the suspension of each isolate was sprayed on 10 seedlings. Ten seedlings sprayed with sterilized distilled water were used as the control. Three replicates were performed on each treatment. The treatment plants were maintained in the incubator (25°C, relative humidity > 80%, 12-h photoperiod). Typical leaf spot symptoms were observed on inoculated leaves after 7 days, the control leaves remained symptomless. The fungus reisolated from the lesions of diseased leaves were morphological and molecularly identical to the inoculated isolates. The results echo with Koch's postulates，suggesting that the obtained isolates SVCT-01, SVCT-02 and SVCT-03 are potential pathogen in Setaria viridis. To confirm the species' identity, total genomic DNA of isolates were extracted using a Fungal DNA Kit (GBCBIO, Guangzhou, China). Sequences of internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT), and β-tubulin (TUB2) regions were identified via PCR (Guerber et al, 2003; Weir et al, 2012). The sequences of SVCT-01, SVCT-02 and SVCT-03 showed more than 99% homology with Colletotrichum truncatum strains CBS:151.35 (GenBank Accession No. GU227862, GU228254, GU227960, GU228156) (Damm, 2009). The sequences of SVCT-01 were deposited in GenBank as a representative isolate under the accession numbers OL629177, OL627527, OM040388, OM040389. Maximum likelihood trees based on concatenated sequences of the four genes were constructed using MEGA7.0. The results showed that the strains isolated from Setaria viridis were closely related to Colletotrichum truncatum with 100% bootstrap support. According to morphological, pathological characteristics, and multilocus phylogenetic analysis, the isolated strains (SVCT-01, SVCT-02 and SVCT-03) from S. viridis were identified as Colletotrichum truncatum (Weir et al, 2012). Colletotrichum sp. is a significant plant pathogen that was previously reported causing anthracnose on Setaria sp. Up to now, it has been reported that C. graminicola has infected nine species of Setaria sp. Such as Setaria glauca in New Zealand (Pennycook, 1989) and Setaria pumila in Zimbabwe (Lenne, 1990). In 1979s, C.graminicola was obtained from Setaria lutescens in China (Tai, 1979). To our knowledge, this is a new host record for Colletotrichum truncatum causing anthracnose on S. viridis in China. Colletotrichum truncatum spread rapidly and caused serious disease to Setaria viridis. We hope to discovery a biocontrol method against weed on non-host cultivated plants through the production of secondary metabolites by C. truncatum.

Bioconversion of Eichhornia crassipes into vermicompost on a large scale through improving operational aspects of in-vessel biodegradation process: Microbial dynamics

Eichhornia crassipes is a common, abundant aquatic weed biomass found globally. The present study examined optimum biodegradation procedures through batch studies (550 L rotating drum composter) and the resulting best combination on a large scale (5000 L rotary drum composter). The pilot scale rotary drum reactor was commenced with cow manure and then treated for 3 months with 250 kg/day of homogenously mixed E. crassipes and dry leaves. The rotary drum's inlet and outlet temperatures were 60 °C and 39 °C, respectively, suggesting thermophilic conditions with a 7-day waste retention duration. Eisenia fetida was used for vermicomposting the outlet material for 20 days, raising the nitrogen content to 3.2%. Bacterial diversity (16S-rRNA) sequencing revealed that Proteobacteria and Euryarchaeota are the most predominant. After 27 days, the volume dropped by 71%, and the product was stable and soil-safe. Large-scale optimised biodegradation may be a better way to handle aquatic weed biomass.

The Effect of Artificial Field Margins on Epigeic Arthropod Functional Groups within Adjacent Arable Land of Northeast China

Providing food security to meet the growing human demand while improving the biodiversity of arable land is a global challenge. Although semi-natural field margins are known to enhance biodiversity in arable land systems globally, the role that abundant artificial field margins play in maintaining epigeic arthropod diversity within arable land remains unclear. Here, we compared epigeic arthropods within adjacent arable land with an artificial field margin (paved and dirt roads) and a semi-natural field margin (ditch, woodland, or grassland), as well as vegetation community characteristics at a field scale for identifying the ecological effects of different field margin types. Our results indicated the following: (i) Compared with semi-natural field margins, there is less epigeic arthropod diversity and less stable ecological networks within adjacent arable land with artificial field margins, with more herbivores within adjacent arable land with artificial field margins and more natural enemies within adjacent arable land with semi-natural field margins. (ii) Arable land adjacent to a dirt road (DR) maintained more resilient ecological networks than that adjacent to a paved road (PR), and there are more flowering plants at DRs, which attracts natural enemies, whereas Orthoptera is more active at PRs with abundant weeds. (iii) The main factors affecting epigeic arthropod functional groups were the tree layer cover (TC), herb layer abundance (HA), and herb layer height (HH) of the artificial and semi-natural field margins. We concluded that increasing the number of flowering plants and removing noxious weeds can eliminate negative effects on epigeic arthropod functional groups within adjacent arable land with artificial field margins. Delineating a certain percentage of vegetation strips to be a buffer zone in artificial field margins or creating a suitable vegetation community in semi-natural field margins can maintain and protect natural enemies and strengthen the ecological network stability between functional groups.

Floristic divergence of weeds in rice fields under subtropical condition

Weed infestation pattern changes over time for continuous adaptation of similar weed control methods. So, a survey was conducted at Agronomy Field Laboratory, Bangladesh Agricultural University from July 2019 to June 2020 to identify the most dominant and abundant weed species as well as to indicate the probable problematic weed in boro and T. aman rice. Seven fields were randomly selected for each of the boro and T. aman rice. The surveys were performed according to quantitative survey technique by using 0.25m2 quadrate with 16 samples from each of the field following the zig-zag method. Sampling was done twice, while the rice plants were at the vegetative stage and at reproductive stage. Fifty one weed species under 23 families were recorded at experimental area of which 42 species (under 18 families) and 38 species (under 20 families) were observed in boro and T. aman, respectively. Poaceae topped the list with 10 species, while Cyperaceae ranked second with six species. The highest number of weed species (no. 42) was observed in boro rice compared to T. aman rice (no. 38). Besides, divergence in the weed composition was also high between both rice fields. Among the 11 abundant weed species, Eleocharis atropurpurea, Echinochloa crusgalli and Monochoria vaginalis were the most frequent and abundant weed species found in both boro rice and T. aman rice. Broadleaves had higher abundance value (246.26% in boro and 332.39% in T. aman) than grasses (188.76% in boro and 146.68% in T. aman) and sedges (164.98% in boro and 120.93% in T. aman). Moreover, the annuals were dominant over the perennials. Therefore, the present results having diversified weed species with different ranks and orders indicated that the weed management strategies should be taken regarding the infestation of dominant weed species of the respective crop.

Weed composition in conventionally and organically grown medical and aromatic plants

This study aimed to compare weed flora in conventionally and organically grown medicinal and aromatic plants (MAPs): basil, pot marigold, dill, and peppermint; in terms of weed composition and weed abundance. A total of 28 weed species (25 and 15 species in conventional and organic crops, respectively) were identified.The presence and abundance of certain weed species were affected by MAP species and farming system. Higher weed diversity and weediness, and lower floristic similarity were found in conventionally grown crops. Also, the analysed MAPs differed in weediness by individual weed species. Correspondence analysis pointed to conventional and organic MAPs with the most frequent and most abundant weed species. Setaria pumila and Portulaca oleracea were the most frequent species in conventional; and Amaranthus retroflexus, Datura stramonium, and Sorghum halepense in organic crops. In both conventional and organic farming systems, therophytes were the most dominant life forms indicating a strong anthropogenic influence. The results should contribute to establishing weed control measures that are adequate for the two farming systems.

Optimising stocking rates on livestock farms neighbouring wetlands for sustainable productivity and ecological stability

Uganda’s wetlands, especially in south-western Uganda are increasingly being invaded by cattle herders, particularly during droughts. Such uncontrolled grazing is accelerating wetland degradation. The objective of this study was to assess seasonal forage availability on farms neighbouring Ekigaaga wetland in south-western Uganda, and to determine their optimum stocking for sustainable productivity and ecological stability. The grazed area on each side of the virgin wetland was taken as a block, giving two blocks. In each block, three square metre sampling plots were demarcated along a transect line cutting across farms adjacent to the wetland. Some of these plots were fenced and others were left open to grazing by livestock. Two months after setting up the study, vegetation samples were collected from the fenced and unfenced plots in each block once every month, for a period of six months. Livestock classes and numbers grazing on each block were established and standardised into Tropical Livestock Units (TLU); where one TLU is equivalent to a cow weighing 250 kg. During wet and dry seasons, Cynodon dactylon was the most abundant forage species in the unfenced plots in both blocks. Fencing increased the prevalence of Chloris gayana and Themeda triandra in block 2. Sporobolus pyramidalis was the most abundant weed in both blocks. Fenced and unfenced plots in block 1 had higher grazeable forage yields (488.05 and 399.97 kg ha-1, respectively) than block 2 (432.08 and 371.97 kg ha-1, respectively). The TLU that could be safely grazed on blocks 1 and 2 were 121 and 107, respectively compared to the TLU being grazed on blocks 1 (279) and 2 (381). Therefore, to sustain the productivity and ecological stability of these grazing areas, there is need to control weeds/thickets, improve forage resources by oversowing with quality forages, and to adjust livestock numbers to match with forage quantities available for grazing.&#x0D;

Diversity of Herbicide-Resistance Mechanisms of Avena fatua L. to Acetyl-CoA Carboxylase-Inhibiting Herbicides in the Bajio, Mexico.

Herbicide resistance is an evolutionary process that affects entire agricultural regions’ yield and productivity. The high number of farms and the diversity of weed management can generate hot selection spots throughout the regions. Resistant biotypes can present a diversity of mechanisms of resistance and resistance factors depending on selective conditions inside the farm; this situation is similar to predictions by the geographic mosaic theory of coevolution. In Mexico, the agricultural region of the Bajio has been affected by herbicide resistance for 25 years. To date, Avena fatua L. is one of the most abundant and problematic weed species. The objective of this study was to determine the mechanism of resistance of biotypes with failures in weed control in 70 wheat and barley crop fields in the Bajio, Mexico. The results showed that 70% of farms have biotypes with target site resistance (TSR). The most common mutations were Trp–1999–Cys, Asp–2078–Gly, Ile–2041–Asn, and some of such mutations confer cross-resistance to ACCase-inhibiting herbicides. Metabolomic fingerprinting showed four different metabolic expression patterns. The results confirmed that in the Bajio, there exist multiple selection sites for both resistance mechanisms, which proves that this area can be considered as a geographic mosaic of resistance.

Assessment of composition and spatial dynamics of weed communities in agroecosystem under varying edaphic factors

Weeds are important components of the agroecosystems due to their role as primary producers within the farming systems, yet they are considered as major constraints to crop production. A phytosociological study was conducted to assess the composition and spatial distribution of existing weed species under the influence of various edaphic factors in the 15 wheat fields. Quadrat method was applied and different phytosociological attributes including abundance, density, and frequency were estimated by randomly laying down 10 square-shaped quadrats of size 1m2 in each wheat field. A total of 34 weed species belonging to 17 families and 30 genera were explored from 150 quadrats. Fabaceae and Asteraceae were ubiquitous plant families. Various edaphic factors such as; soil texture, electrical conductivity, soil pH, total dissolved solids, nitrogen, calcium carbonate, organic matter, NaCl, calcium, phosphorous, potassium, sodium, and zinc were determined. Pearson's correlation was employed to correlate weeds and the potential edaphic variables. The results depicted that most of these weed pairs' associations correlated positively. Simultaneously, the abundant weed species including Trifolium repens, Coronopus didymus, and Urtica dioica showed a positive correlation with most of the investigated ecological variables.

Weed Composition in Hungarian Phacelia (Phacelia tanacetifolia Benth.) Seed Production: Could Tine Harrow Take over Chemical Management?

Phacelia tanacetifolia, an excellent cover, green manure and honey crop is now widely cultivated throughout the world. One of its principal European seed production regions is north-western Hungary, where the recent withdrawal of a potent herbicide, linuron, created a new challenge for many growers. The goal of this study is to identify the main factors determining weed species composition in the phacelia fields of the region and to assess the efficiency of tine harrow and clopyralid herbicide in reducing weed abundance and biomass. We carried out a series of weed surveys across the study region following a two-level design: (i) we estimated the cover of all weed species in 205 fields (broad-scale survey, BS); and (ii) in 22 of these fields, we provided more precise biomass measurements (counting the individuals and measuring the dry weights of all weed species) in microplots samples (fine-scale survey; FS). To characterize the fields, 34 background variables were also collected for all of the studied fields. In both investigations, Chenopodium album was by far the most abundant weed. Within the BS, using a minimal adequate model containing 11 terms with significant net effects, 20.93% of the total variation in weed species data could be explained. The variation in species composition was determined by environmental factors (soil pH, clay and K; precipitation and temperature), non-chemical management variables (crop cover, preceding crop, irrigation and tillage system) and herbicides (linuron and clopyralid). Variation partitioning demonstrated the dominance of environmental and cultural components in shaping the weed species composition. Although the effect of mechanical treatments was most likely masked in the BS by the soil properties, our FS suggests that tine harrow could efficiently decrease the total number and biomass of weeds and can be a useful tool in the phacelia management of the future.