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

2017 ◽  
Vol 35 (0) ◽  
Author(s):  
J.A.A. ALBUQUERQUE ◽  
T.S. SANTOS ◽  
T.S. CASTRO ◽  
V.F. MELO ◽  
P.R.R. ROCHA

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.

2011 ◽  
Vol 29 (3) ◽  
pp. 515-522 ◽  
Author(s):  
G Concenço ◽  
J.C Salton ◽  
M.L Secretti ◽  
P.B Mendes ◽  
R.C Brevilieri ◽  
...  

This study aims to assess the composition of weed communities as a function of distinct selection factors, at neighboring areas submitted to distinct soil management and diverse use for sixteen years. Four areas submitted to distinct managements (conventional tillage system; no-till system; integration crop/livestock and continuous livestock) were sampled in relation to the occurrence and severity of weed species by the beginning of the planting season, being estimated the relative abundance, relative frequency and relative dominance of each weed species under each area, as well as the Importance Value Index for each species. Areas were also compared by the Sørensen's similarity coefficient. Areas where pasture and grazing were never present, exhibited a number of seedlings of weed species 250% higher than areas periodically or continuously under grazing, while the area of soil covered by weeds was 87% superior at the conventional tillage system in relation to the average of the other treatments. Grass weeds were the most important at the conventional tillage area while broadleaved weeds where more important at the no-till area, probably due also to herbicide selection factors. Under crop/livestock integration there may be the need to care about controlling seedlings of the forage species inside grain crops in succession.


2020 ◽  
Vol 12 (11) ◽  
pp. 179
Author(s):  
Simônica Maria De Oliveira ◽  
Abner José De Carvalho ◽  
Ignacio Aspiazú ◽  
Polyanna Mara De Oliveira ◽  
João Victor Santos Guerra ◽  
...  

The objective was to identify the species and quantify the importance value index of weeds in the cultivation of arabica coffee in two irrigation systems, at different times of the year, in the northern region of Minas Gerais. A phytosociological survey was carried out in each season of the year (spring, summer, autumn and winter) in an area cultivated with the species Coffea arabica, subjected to two irrigation systems (sprinkling and dripping). The coffee crop was implanted at a spacing of 3.5 m between rows and 0.7 meters between plants. The collection of weeds was performed using the standard method of the square inventory, which was launched between the lines of the crop. The identification of the species was carried out, the number of individuals was quantified, the dry mass, frequency, density, abundance, importance value index and coverage, and the similarity index. 33 weed species were identified, being the species with the highest IVI Euphorbia hirta, Brachiaria plantaginea, Digitaria horizontalis, Cyperus rotundus and Amaranthus spp. It was observed a higher occurrence of weeds from the monocot group in the sprinkler irrigation system while in the drip there were predominance of dicot plants.


2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.C. DIAS ◽  
M.V. SANTOS ◽  
E.A. FERREIRA ◽  
T.G.S BRAZ ◽  
L.V. FIGUEIREDO ◽  
...  

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.


Agrarian ◽  
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

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.


Nativa ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 427-435
Author(s):  
Davair Lopes Teixeira Junior ◽  
José Maria Arcanjo Alves ◽  
José Anchieta Alves Albuquerque ◽  
Paulo Roberto Ribeiro Rocha ◽  
Thais Santiago Castro ◽  
...  

Sistemas de manejos das plantas daninhas, utilizando diferentes estratégias de controle, podem alterar a dinâmica populacional das plantas e favorecer o controle de algumas espécies. Objetivou-se com esse trabalho avaliar a ocorrência de plantas daninhas antes e após cultivo de feijão-caupi, em plantio direto, sob quatro formas de manejo da vegetação natural (sem roçada, com roçada, uso de fogo e dessecação com glyphosate) em área da savana Amazônica no estado de Roraima. As avaliações foram realizadas mediante a aplicação do método do quadrado inventário. As plantas daninhas situadas nas áreas amostradas foram cortadas rente ao solo, identificadas e quantificadas. Os parâmetros fitossociológicos analisados foram: frequência relativa, densidade relativa, abundância relativa, índice de valor de importância e índice de similaridade. As principais famílias identificadas foram Cyperaceae, Poaceae e Fabaceae. As formas de manejo da vegetação natural da savana de Roraima para o cultivo do feijão-caupi favoreceram a emergência de 10 espécies de um total de 29. O manejo com o herbicida glyphosate proporcionou o desenvolvimento das espécies Digitaria insularis e Hynchelitrum repens e o controle de 12 espécies, entre elas o Trachypogon plumosus, importante forrageira da região em estudo. O manejo da vegetação natural com o fogo favoreceu o surgimento da espécie Desmodium tortuosum. O manejo com glyphosate promoveu alterações na comunidade infestante de plantas daninhas, nesse foi observado os menores índices de similaridade entre os sistemas de manejo avaliados.Palavras-chave: fitossociologia; Vigna unguiculata; vegetação natural; manejo com fogo. OCCURRENCE OF WEEDS IN COWPEA CULTURE UNDER FOUR HANDLES IN THE WESTERN AMAZON ABSTRACT: Weed management systems, using different control strategies, can change the population dynamics of plants and favor the control of some species.The objective of this work was to evaluate the occurrence of weeds before and after cowpea cultivation under no-tillage under four forms of natural vegetation management (no-till, no-till, use of fire and glyphosate desiccation) in an area of savannah of Roraima. Evaluations were performed by applying the inventory square method. Weeds located in the sampled areas were sectioned close to the ground, identified and quantified. The phytosociological parameters analyzed were: relative frequency, relative density, relative abundance, importance value index and similarity index. The main families identified were Cyperaceae, Poaceae and Fabaceae. The management of the natural vegetation of the Roraima savanna for cowpea cultivation favored the emergence of 10 species out of 29. Management with the herbicide glyphosate provided the appearance of the species Digitaria insularis and Hynchelitrum repens and the control of 12 species, including the Trachypogon plumosus, an important savanna forage. The management of natural vegetation with fire favored the emergence of the species Desmodium tortuosum. Glyphosate management caused changes in the weed community, which showed the lowest similarity indexes between the evaluated management systems.Keywords: phytosociology; Vigna unguiculata; natural vegetation; fire management.


2018 ◽  
Vol 17 (3) ◽  
pp. 390
Author(s):  
TALITA CAMARGOS GOMES ◽  
DÉCIO KARAM

RESUMO: O conhecimento de uma comunidade infestante é necessário para se avaliar o nível de dano que esta pode causar na produtividade de qualquer cultura. Assim, o objetivo do estudo foi realizar levantamento fitossociológico exploratório de plantas daninhas em áreas com sorgo sacarino e granífero em função de densidades e espaçamentos de plantas de sorgo como forma de manejo cultural. O estudo foi conduzido em campo, com delineamento experimental de blocos casualizados, em esquema fatorial 2 x 2 x 2 com três repetições, sendo os tratamentos representados por duas cultivares de sorgo, BRS 506 e BR 330, semeadas em duas densidades (100.000, e 200.000 plantas ha-1) e dois espaçamentos (0,25 e 0,7 m) entre linhas. O levantamento das espécies infestantes foi realizado aos 56 dias após a emergência (DAE) do sorgo, pelo método do quadrado inventário. Observou-se que as diferenças em Índice de Valor de Importância para a mesma espécie daninha estão relacionadas à mudança na densidade e no espaçamento da cultura do sorgo.Palavras-chave: Sorghum bicolor, BRS 506, BR 330, fitossociologia, manejo cultural. POPULATION DYNAMICS OF WEED IN AREAS WITH SWEET SORGHUM AND GRAIN SORGHUM WITH DIFFERENT SPACINGS AND PLANTING DENSITIES  ABSTRACT – Knowing a weed community is important to estimate the level of damage that may cause to the productivity of any crop. Thus, the aim of the present study was to perform a phytosociological survey of weeds in areas with saccharine and grain sorghum considering the interaction between density and spacing of sorghum plants as a form of crop management. The study was conducted at field in a randomized block design with a 2 x 2 x 2 factorial scheme and three replications. Two sorghum cultivars (BRS 506 and BR 330) were seeded at two densities (100,000 and 200,000 plants ha-1) and two row spacings (0.25 and 0.7 m). The evaluation of the weed species was performed 56 days after emergence (DAE) of sorghum using the inventory square method. The dry mass of the weed species was determined. It was observed that the differences in the importance value index of the same weed species are related to changes in the density and spacing of sorghum.Keywords: Sorghum bicolor, BRS 506, BR 330, phytosociology, crop management.


Nativa ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 500
Author(s):  
Flávio Henrique Silva de Sena ◽  
Ignacio Aspiazú ◽  
Natanael Pereira da Silva ◽  
Renato Mendes de Oliveira ◽  
Karen Marcelle de Jesus Silva ◽  
...  

Objetivou-se identificar as principais espécies de plantas daninhas em cultivo de mangueira aos dois e oito anos após plantio. O estudo foi desenvolvido em áreas irrigados de manga ‘Palmer’ localizadas em Janaúba-MG. Para estudo fitossociológico das plantas daninhas foi utilizado o método quadrado inventário (0,25 m2). Após classificação e quantificação das espécies, foi calculado calcularam-se a frequência (F), frequência relativa (Fr), densidade (D), densidade relativa (Dr), abundância (A), abundância relativa (Ar), índice de valor de importância (IVI), índice de valor de importância relativa (IVIr) e índice de similaridade. Na área com cultivo de mangueira em produção, após oito anos do plantio, foram encontradas 17 espécies, 14 gêneros e oito famílias, sendo Sida rhombifolia a principal espécie com IVIr de 27,8%. Já na área com dois anos de plantio encontrou-se menos espécies com destaque para Paspalum urvillei com IVIr de 70,61%. O índice de similaridade entre as duas áreas foi de 18,18%. Portanto, conclui-se que nas condições locais do cultivo de mangueira de Janaúba-MG, P. urvillei e S. rhombifolia são as principais espécies encontradas em pomares após dois e oito anos após implantação, respectivamente, e além disso, estes apresentam diferentes espécies infestantes comprovado pelo valor do índice de similaridade.Palavras-chave: fitossociologia; plantas daninhas; Mangifera indica. WEED PHYTOSOCIOLOGICAL SURVEY ON MANGO ORCHARDS IN THE MINAS GERAIS SEMIARID ABSTRACT: This study aimed to identify the main weed species in mango cultivation at two and eight years after planting. The study was developed in irrigated areas of 'Palmer' mango located in Janaúba-MG. For weed phytosociological study, the square inventory method (0.25 m2) was used. The frequency (F), relative frequency (Rf), density (D), relative density (Rd), abundance (A), relative abundance (Ra), value index of importance (VII), relative importance value index (RIVI) and similarity index were determined. In the area with mango cultivation in production, after eight years of planting, 17 species, 14 genera and eight families were found, being Sida rhombifolia the main species, with RIVI of 27.8%. In the area with two years of cultivation were found less species, with emphasis to Paspalum urvillei, with RIVI of 70.61%. The similarity index between the two areas was 18.18%. Therefore, it is concluded that in the local conditions of the cultivation of mango of Janaúba-MG, P. urvillei and S. rhombifolia are the main species found in orchards after two and eight years after implantation, respectively, and, in addition, both present different weed species, as proven by the low similarity index value.Keywords: phytosociology; weed; Mangifera indica.


2018 ◽  
Vol 35 (1) ◽  
pp. 173-181
Author(s):  
S. Khanal ◽  
S. Adhikari ◽  
A. Bhattarai ◽  
S. Shrestha

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.


2012 ◽  
Vol 30 (4) ◽  
pp. 747-755 ◽  
Author(s):  
G. Concenço ◽  
C.J. Silva ◽  
L.A. Staut ◽  
C.S. Pontes ◽  
L.C.A.S. Laurindo ◽  
...  

In the Western Region of Brazil, it is usual to have two agricultural harvests in the same cropping season. Usually the first crop is soybean, followed by corn. In areas where corn is not planted due to a delayed harvest of soybean, farmers generally do not use winter crops. For these areas, the planting of winter oilseed crops aiming at the production of bio-fuels is one of the best alternatives; in addition, this would help in reducing the occurrence of weed species at the following summer crop. This study aimed to assessing the weed community in distinct winter crops post soybean crop, in terms of species composition, level of infestation and severity of occurrence. The following treatments were evaluated: agriculture under a no-till system with winter fallow, winter oilseed crops (crambe, radish, rapeseed) with no-till agriculture in the summer, and agriculture under a conventional tillage system with winter fallow. Phytosociological evaluations of all treatments were carried out 75 DAE of the oilseed crops, and the diversity indexes of Margalef, Menhinick, Simpson, and Shannon-Weiner were determined. Areas were also grouped by cluster analysis based on UPGMA applied at Jaccard's similarity matrix. Among the treatments with winter coverage, radish was the most efficient crop in suppressing the occurrence of weed species. The area with conventional tillage agriculture and winter fallow allowed for a higher occurrence of troublesome weeds. On the other hand, the area under fallow showed the highest absolute level of infestation. Overall, oilseed crops in the winter contribute to lower levels of infestation by weed species in these areas.


2018 ◽  
Vol 20 (1) ◽  
pp. 259-266
Author(s):  
FAIZAL KASIM ◽  
MIFTAHUL KHAIR KADIM ◽  
SITTI NURSINAR ◽  
ZULKIFLI KARIM ◽  
ALDIN LAMALANGO

Kasim F, Kadim MK, Nursinar S, Karim Z, Lamalango A. 2019. Comparison of true mangrove stands in Dudepo and Ponelo Islands, North Gorontalo District, Indonesia. Biodiversitas 20: 259-266. This study aimed to investigate and compare the current status of mangrove areas, as well as the composition and species diversity of mangrove stands in both regions of Dudepo and Ponelo Islands. The results showed that the mangrove areas calculated using the segmentation method in classifying image of Landsat-8 OLI (acquisition on September 2017) were 279.46 ha (Dudepo Island) and 113.35 ha (Ponelo Island) respectively. A total of 13 species of true mangrove were recorded from both islands, using survey method from 9 transect lines (TL), with a distance ranging from 40 to 210 meters (1-6 quadrats) per transect. The mean densities of trees were 2133 ± 329.78 ha-1 (Dudepo Island) and 2111 ± 234.28 ha-1 (Ponelo Island), while those of saplings and seedlings were 58 ± 13.48 ha-1 and 1425 ± 113.96 ha-1 (Dudepo Island), and 79 ± 14.51 ha-1 and 2963 ± 443.22 ha-1 (Ponelo Island). The mean diameter and basal area were 19.73 ± 10.65 cm and 84.22 ± 67.67 m2ha-1 (Dudepo Island), 17.04 ± 1.46 cm and 60.07 ± 15.12 m2ha-1 (Ponelo Island), respectively. The Importance Value Index (IVI) ranged between 3.97-114.87 (Dudepo Island) and 6.04-82.18 (Ponelo Island). The dominant and codominant species based on IVI in both islands were Rhizophora apiculata Blume and R. stylosa Griff. The indexes of diversity, richness, and evenness of mangrove species in both islands were 0.34-1.70, 0.48-1.18, 0.47-0.94 (trees), 0.00-1.10, 0.00-1.82, 0.00-1.00 (saplings), and 0.00.-1.48, 0.00-1.44, 0.72-1.00 (seedlings), respectively. The Bray-Curtis similarity index between Dudepo and Ponelo Islands, based on the overall values of community attributes, was 0.75.


Sign in / Sign up

Export Citation Format

Share Document