Phytosociological survey of weed plants in soybean culture in the Gurguéia Valley

Phytosociology is a set of ecological assessment methods that aim to provide a view of plant species distributions within a plant assemblage. The objective of the current study was to identify and quantify the plants designated as weeds in a glyphosate-resistant soybean crop, using a phytosociological survey of a conventional planting system on the Fazenda Agrosantos (09°27’4124.4” S and 45º01’00.4” O), Vale do Gurguéia, Monte Alegre municipality Piauí state, Brazil. The site lies at a mean altitude of 652 m. Field collections were made 15 days after initial soya planting. For sampling, a 0.40 x 0.40 m quadrat was used, thrown randomly twenty times within the experimental area. Weeds were identified and quantified using the sum of the samples obtained from the quadrat samples. Plants that lay within the quadrat were identified, counted and collected for identification, which was carried out by comparison with specialist bibliographies and weed identification manuals. Evaluated variables were: frequency, density, abundance, relative frequency, relative density, relative abundance and species importance value index. In the soybean cultivation area, 60% of the sampled species were Eudicotyledons, and a total of 8 botanical families and 10 weed species were identified. The species Cenchrus echinatus, Ipomoea asarifolia (Desr.) Roem. & Schult, Amaranthus retroflexus L. and Zea mays L showed the highest values for the analyzed variables, and should therefore be of special attention to soybean producers in the region of Vale da Gurguéia, Piauí, Brazil.

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Phytosociology in Degraded and Renewed Pastures in Agrosilvopastoral Systems

Planta Daninha ◽

10.1590/s0100-83582018360100075 ◽

2018 ◽

Vol 36 (0) ◽

Author(s):

R.C. DIAS ◽

M.V. SANTOS ◽

E.A. FERREIRA ◽

T.G.S BRAZ ◽

L.V. FIGUEIREDO ◽

...

Keyword(s):

Similarity Index ◽

Weed Species ◽

Importance Value Index ◽

Importance Value ◽

Brachiaria Decumbens ◽

Agrosilvopastoral Systems ◽

Before And After ◽

One Year ◽

Sida Cordifolia

ABSTRACT: In pastures, the incidence of weeds reduces the productivity and quality of forage. The identification of the weed species in pastures is fundamental to choose the renewal method. Thus, the objective of this work was to perform phytosociology before and after the renewal of a Brachiaria decumbens pasture, with the implantation of agrosilvopastoral systems. Eighteen different crop arrangements for pasture renewal were evaluated. The renewal systems were by eucalyptus integration (at 12 x 2 m or 12 x 3 m spacings) with maize, Brachiaria brizantha cv. Marandu (palisade grass) and/or Macrotyloma axillare (perennial horsegram), or monoculture and intercropping of palisade grass and perennial horsegram, as well as the evaluation of the application or not of the herbicide bentazon, at the recommended dose for maize crops (0.72 kg ha-1). Relative frequency, relative density, relative abundance, relative dominance, coverage value index, importance value index, dry matter and similarity index were evaluated. In the first survey, before the pasture renewal, 23 plant species were identified. After the implantation of agrosilvopastoral systems, the species Sida cordifolia, Lantana camara and B. decumbens were the only occurring ones before and after the renewal of the pasture with agrosilvopastoral systems. The use of palisade grass and the application of the herbicide were efficient in controlling weeds. In systems that contained palisade grass and perennial horsegram, the latter was not found in the survey conducted one year after the implantation.

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WEED INCIDENCE AFTER SOYBEAN HARVEST IN NO-TILL AND CONVENTIONAL TILLAGE CROPROTATION SYSTEMS IN RORAIMA’S CERRADO

Planta Daninha ◽

10.1590/s0100-83582017350100034 ◽

2017 ◽

Vol 35 (0) ◽

Author(s):

J.A.A. ALBUQUERQUE ◽

T.S. SANTOS ◽

T.S. CASTRO ◽

V.F. MELO ◽

P.R.R. ROCHA

Keyword(s):

Similarity Index ◽

Dry Mass ◽

Conventional Tillage ◽

Weed Species ◽

Importance Value Index ◽

Importance Value ◽

No Till ◽

Rotational Systems ◽

Botanical Classification

ABSTRACT The goal of this study was to evaluate the occurrence of weeds after soybean harvest in rotational systems of no-till and conventional tillage in the savannah of Roraima, Brazil. Two simultaneous experiments were conducted in adjacent areas, the first one with no-till soil management system and the second one with the conventional system, with crop rotations for five agricultural years: pearlmillet (2007/2008), soybean (2008/2009), maize (2009/2010), cowpea with maize (2010/2011), soybean (2011/2012) and maize (2012/2013). The used experimental design was the randomized block one with 28 plots, sized 3 x 15 m (45 m2) distributed in 4 blocks. In May 2010, the combined sowing of cowpea and maize was performed, and later, during the same month of 2011 soybean was sown. Thirty days after harvesting, weeds were collected. The botanical classification of species was performed by classes, families, scientific and popular names, as well as comparisons with specialized bibliographies. The evaluated phyto-sociological parameters were: relative frequency (FRR), relative density (DRR), dominance (Do), importance value index (IVI), Sorensen’s similarity index (SI), numbers of individuals (ha-1) and dry mass (%). Among the 37 species found in both planting systems, 60% belonged to the Liliopsida class; Fabaceae and Malvaceae stood out. However, Poaceae, belonging to the Magnoliopsida class, had the highest number of species in both systems. Most weed species were common in both systems.

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Diversity of Weeds and Population Dynamics of Predators and Prey Present in Wheat-Mustard Ecosystem at Paklihawa, Rupandehi, Nepal

Journal of the Institute of Agriculture and Animal Science ◽

10.3126/jiaas.v35i1.22538 ◽

2018 ◽

Vol 35 (1) ◽

pp. 173-181

Author(s):

S. Khanal ◽

S. Adhikari ◽

A. Bhattarai ◽

S. Shrestha

Keyword(s):

Population Dynamics ◽

Chenopodium Album ◽

Effect Of Temperature ◽

Weed Species ◽

Importance Value Index ◽

Importance Value ◽

Mustard Aphid ◽

Wooden Frame ◽

Index Value ◽

The Given

A study was conducted at Institute of Agriculture and Animal Science (IAAS), Paklihawa Rupandehi, agronomy field to study the diversity of weeds and population dynamics of predators and prey in wheat-mustard ecosystem. The study was conducted by quadrate sampling method using the wooden frame by selecting 40 sample spots, and locating its coordinates. Predator, prey, some of the beneficial and harmful insects as well as weed species was recorded in 5 days interval in the study. Relationships between the population of the mustard aphid and wheat aphid, lady bird beetle to maximum and minimum temperature were recorded in order to know the effect of temperature in relation to population density. Number of mustard aphid and its nymph has shown the positive significant relationship with the population of the spider in the wheat mustard ecosystem. Shannon Weiner Index value was calculated and the species richness was found to be 2.63 with the effective number of species value 9. The species evenness value was found to be 0.83 in the studied ecosystem which signifies that the given weed ecosystem is somewhat even. The importance value index (IVI) of the given ecosystem with the value of different weed species was calculated and it was found that the weed Anagalis arvensis was ranked as first with the IVI value of 57.98 following Vicia sativa and Chenopodium album. This signifies that the species Anagalis arvensis has greater control over the wheat mustard ecosystem of Paklihawa, Rupandehi.

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Ervas daninha em pastagens: uma abordagem fitossociológica nas áreas do Ceará

Agrarian ◽

10.30612/agrarian.v12i45.7048 ◽

2019 ◽

Vol 12 (45) ◽

pp. 279-285

Author(s):

Josefa Maria Francieli da Silva ◽

Hercules Gustavo Santos Sarmento ◽

Hellen Thayse Nascimento Araújo ◽

Alexandre Bosco de Oliveira ◽

Lamartine Soares Cardoso de Oliveira

Keyword(s):

Relative Frequency ◽

Similarity Index ◽

Cyperus Rotundus ◽

Weed Species ◽

Importance Value Index ◽

Importance Value ◽

Brachiaria Decumbens ◽

The One ◽

Absolute Dominance ◽

Nicandra Physalodes

The aim of this study was to study the phytosociology of weed species in areas of pasture cultivated with Brachiaria decumbens and Cynodon sp. (Tifton 85), in Ceará State, Brazil. The square inventory methodology was used in order to assess the weed community. Weed samples were quantified and classified by family, genus and species, using books and classification keys. The classification and quantification data of species allowed to calculate the following phytosociological variables: frequency (F), relative frequency (Fr), density (D), relative density (Dr), absolute dominance (DoA), relative dominance (DoR), importance value index (IVI), and similarity index (IS). The Amaranthaceae family was the one with the greatest intensity of species in both areas, represented mainly by Alternanthera tenera colla and Amaranthus viridis. In the area cultivated with B. decumbens, Cyperus rotundus presented higher results for frequency, density and abundance. In the Tifton 85 area, Nicandra physalodes presented higher values of density and abundance. The similarity of weed populations in pasture areas was 42.11%, with four species common to both areas.

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Keanekaragaman Coccinellidae Predator Pada Beberapa Ekosistem Perkebunan di Kabupaten Dharmasraya

Biosfer Jurnal Tadris Biologi ◽

10.24042/biosfer.v10i2.5558 ◽

2019 ◽

Vol 10 (2) ◽

pp. 157-168

Author(s):

Siska Chiko Efendi ◽

Yaherwandi Yaherwandi ◽

Ade Noferta ◽

Aditya Muhammad

Keyword(s):

Species Diversity ◽

Dominant Species ◽

Wiener Index ◽

Simpson Index ◽

Importance Value Index ◽

Importance Value ◽

Important Value Index ◽

Sweep Net ◽

Species Importance

The objectives of this research were to study the species diversity and to determine the dominant species of lady bird beetle predators in high land plantation ecosystem in West Sumatera. The samples were taken by hand collection and sweep net. The data of species diversity were analyzed using Shannon-Wiener index, evenness of species were analyzed by Simpson index, and dominant species using important value index. The results showed that there were 91 individuals predator found which consisted of 7 species. The highest species diversity (1.74) and evenness (0.89) were found in Pulau Punjung. The lowest diversity and evennes (1,40) and (0,75) was found in Koto Besar. The highest species importance value index was 1,00, that was Menochillus sexmaculatus.

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DISTRIBUTION PATTERN OF WEEDS IN WHEAT CROP GROWN IN DISTRICT KHANEWAL, PUNJAB, PAKISTAN

JOURNAL OF WEED SCIENCE RESEARCH ◽

10.28941/pjwsr.v26i1.806 ◽

2020 ◽

Vol 27 (2) ◽

pp. 47-59 ◽

Cited By ~ 1

Author(s):

Muhammad Usman ◽

Ghulam Murtaza ◽

Allah Ditta ◽

Tamana Bakht ◽

Muhammad Asif ◽

...

Keyword(s):

Distribution Pattern ◽

Growth And Yield ◽

Survey Study ◽

Cereal Crops ◽

Wheat Crop ◽

Weed Species ◽

Importance Value Index ◽

Importance Value ◽

Factors Affecting ◽

Weed Infestation

Weed infestation is among the main biotic factors affecting growth and yield of various crops. This issue is more drastic for cereal crops like wheat which is the staple food crop of over 2.5 billion population of the world. One the control strategy is the investigated the distribution pattern of weeds under field conditions. In this regard, a survey study was conducted to investigate the distribution pattern of weed species in wheat crop during 2016-18 in district Khanewal, Punjab Pakistan. Thirty-six weed species distributed among fifteen different families collected from the study area. Family Poaceae was dominant with 10 species while family Asteraceae was the second most dominant family with four weed species. Cynadon dactylon was the most frequently found specie with frequency value 79.1% while Paspalum distichum had the highest importance value index (6.96) among the weeds of the study area.

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Management of soil cover and its influence on phytosociology, physiology and fig production

Comunicata Scientiae ◽

10.14295/cs.v11i0.3236 ◽

2020 ◽

Vol 11 ◽

pp. e3236

Author(s):

Thiago da Costa ◽

Clevison Luis Giacobbo ◽

Leandro Galon ◽

Cesar Tiago Forte ◽

Richardson Damis ◽

...

Keyword(s):

Aerial Part ◽

Block Design ◽

Dry Mass ◽

Total Production ◽

Importance Value Index ◽

Importance Value ◽

Physiological Variables ◽

Randomized Complete Block Design ◽

Crop Cycle ◽

Species Importance

The fig stands out as an important source of food for the human diet, especially minerals and fibers. Weeds are a major concern in the conduct of fig orchards. Therefore, the objective of this study was to evaluate the effect of management of vegetable cover of soil (CVS) on weed phytosociology, physiological characteristics and fig production. The experimental design was a randomized complete block design with four replications. The treatments consisted of six CVS managements: cover maintenance, weeding, lodging, mowing, application of herbicides diquat and glyphosate. For the constitution of the vegetal cover a consortium of three winter forage species, vetch and black oats sowed and the ryegrass remaining in the area of previous years were used. Thus, we evaluated the phytosociology of weeds present in the area, at two different times, assigning parameters related to frequency, density and abundance, which establish the species importance value index (IVI), besides the dry mass of the aerial part of the weeds. Physiological parameters and total fruit yield were evaluated at the end of the crop cycle. The different CVS management methods influenced the weed community, mainly in the diversity, density and dry mass of the aerial part. There is no interference in the physiological variables of the fig plants and in the total production of fig fruits. We highlight the maintenance of coverage and lodging as the most promising for the management of weeds found fig orchards.

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Weed phytosociology in diversified soybean production systems

Semina Ciências Agrárias ◽

10.5433/1679-0359.2021v42n6supl2p3567 ◽

2021 ◽

Vol 42 (6supl2) ◽

pp. 3567-3580

Author(s):

Ivan Bordin ◽

◽

Osmar Maziero Buratto ◽

Andreia Cristina Peres Rodrigues da Costa ◽

Benedito Noedi Rodrigues ◽

...

Keyword(s):

Management Practices ◽

Production Systems ◽

Integrated Management ◽

Management Strategies ◽

Suppressive Effect ◽

Ecological Interactions ◽

Weed Species ◽

Importance Value Index ◽

Importance Value ◽

Commelina Benghalensis

The knowledge of the impacts of the management practices used in each agricultural production system on the ecological interactions between commercial crops and weed populations can assist in the development of specific and sustainable integrated management strategies. This study aimed to assess weed communities in soybean in succession to second-crop corn and production systems with crop diversification in Northern Paraná State. The study was conducted during three agricultural years (2014/2017). Six treatments were setup: 1 – corn/soybean, corn/soybean, and corn/soybean), 2 – white oat/soybean, rye/corn, and wheat/soybean, 3 – oat + rye/soybean, oat + radish/corn, and congo grass/soybean, 4 – canola/corn, crambe/corn, and safflower/soybean, 5 – buckwheat/ radish/corn, bean/soybean, and buckwheat/oat/soybean, and 6 – wheat/corn + congo grass, canola/corn, and bean/soybean. The relative importance value index of each weed species and the soil cover (soil, straw, and weeds) were assessed. The experimental design consisted of randomized blocks with four replications of 300 m2 (20 × 15 m). The production systems white oat/soybean, rye/corn, and wheat/soybean; buckwheat/radish/corn, bean/soybean, buckwheat/oat/soybean; and wheat/corn+congo grass, canola/corn, bean/soybean had a suppressive effect on the species Commelina benghalensis. Euphorbia heterophylla and Digitaria horizontalis were the species most adapted to the assessed production systems. Seeds remaining from crambe and radish cultivations became volunteer plants in subsequent cultivations.

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Technology Levels in Cassava Cultivation Alter Phytosociology of Weeds

HortScience ◽

10.21273/hortsci15643-20 ◽

2021 ◽

pp. 1-8

Author(s):

Isabel Schlegel Werle ◽

Alencar Junior Zanon ◽

Nereu Augusto Streck ◽

Carlos Eduardo Schaedler ◽

Felipe Schmidt Dalla Porta ◽

...

Keyword(s):

Field Experiments ◽

Weed Species ◽

Importance Value Index ◽

Importance Value ◽

Dissimilarity Matrix ◽

Weed Diversity ◽

Poaceae Family ◽

Cassava Production ◽

Technology Level ◽

Santa Maria

This study aimed to assess the phytosociology of weeds as a function of different crop management technology levels in cassava production. Field experiments were conducted in Santa Maria (29°41′03″ S; 53°48′25″ W) and Itaqui (lat. 29°07′31″ S; long. 56°33′11″ W), Rio Grande do Sul, Brazil. Treatments consisted of three technology levels: low (postemergence weeding without basal dressing); medium (weeding performed at 7 and 40 days after planting and fertilization with 6.25, 25, and 25 kg⋅ha−1 of N, P, and K, respectively); and high (postemergence application of s-metolachlor; 1250 kg⋅ha−1 of lime and 12.5, 50, and 50 kg⋅ha−1 of N, P, and K, respectively). Weed frequency, density, relative abundance, and importance values were calculated for each location. Then, locations were compared using a dissimilarity matrix. Weed density and diversity decreased linearly as technology levels increased. The predominant weed species found in Itaqui and Santa Maria belong to the Poaceae family. Itaqui presented highest weed diversity among the locations. The genus Cyperus had the highest importance value index in Santa Maria. The use of S-metolachlor at the high technology level provided a lower frequency and lower diversity of weed species than did levels without chemical control in Itaqui and Santa Maria.

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Weed Survey Associated in Tobacco (Nicotiana tabacum L.) in Bilatte Tobacco Farm, Ethiopia

Advance in Biological Research ◽

10.26855/abr.2020005 ◽

2020 ◽

Vol 1 (1) ◽

pp. 29-33

Author(s):

Daniel Abebe ◽

Mekonnen Tadesse

Keyword(s):

Relative Abundance ◽

Cynodon Dactylon ◽

Datura Stramonium ◽

Survey Method ◽

Cyperus Esculentus ◽

Weed Species ◽

Importance Value Index ◽

Importance Value ◽

Nicotiana Tabacum L ◽

Weed Survey

An in-field weed survey method was conducted to estimate the most frequently, density and abundance weed species present in Bilatte tobacco farm, Ethiopia during 2014 totally covered approximately 145 hectares. During study period a total number of 14 weed species belonging to 06 monocot and 08 dicot families were recorded out of 7 families of weed reported form study site. The most predominate was shown by monocot Poaceae having 4 weed species followed by dicot family Composite having 3 weeds. The families Cyperaceous, Solanaceae and Amaranthaceous each having 2 weeds, and the family Papaverceae represented by 1 weed. Based on % of frequency Cyperus esculentus (sedges) family Cyperaceous was 99.30. The data showed that Cynodon dactylon and Digitaria abyssinica belong to family Poaceae and Cyperus esculentus family Cyperaceous were the most abundant weed with a density of 35.9, 14 and 12 of plant m-2 respectively. Relative abundance values quantify the overall weed problem posed by specie Cyperus esculentus that had higher relative abundance was 98.97. The importance value index indicated that Cyperaceous and Poaceae families can be considered the great potential to cause reduce tobacco production. Whereas, Solanium nigrum and Datura stramonium were observed with least population density 0.00 and 1.03 plant m-2, least frequently 2.7 and 13.51 %, least relative weed abundance, 0.07 and 1.03 with importance value index 2.8 and 14.8 occurring weed respectively.

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