Levantamento fitossociológico de plantas daninhas em pastagens degradadas do Médio Vale do Rio Doce, Minas Gerais

Ferreira, Evander Alves; Fernandez, Anselmo Grossi; Souza, Celiomar Pereira de; Felipe, Marcia Aparecida; Santos, J.B.; Silva, Daniel Valadão; Guimarães, Fernanda Aparecida Rodrigues

doi:10.1590/0034-737x201461040008

Cited by 21 publications

(24 citation statements)

References 16 publications

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“…On grazing areas, the diversity was low, since this is a very peculiar, poorly managed and compacted environment, determining that only the species with higher adaptation capacity to these conditions will germinate and proliferate. Ferreira et al (2014), when studying the diversity of weeds on degraded grazing areas on different locations of the Médio Vale do Rio Doce, observed a large diversity across the studied areas; however, within each location, there was a higher diversity on some places and, on others, the diversity was very low. Jakelaitis et al (2014) found low values for Shanonn's index (between 1.33 and 1.70) on cultured areas with pastures.…”

Section: Resultsmentioning

confidence: 90%

Bank of Weed Seeds in Agrosystems in the Brazilian Cerrado

et al. 2016

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-The seed bank is the reserve of viable seeds found in the soil and is related to diversity and abundance of species that make up the weed populations. This study aimed to determine the seed bank in four distinct environments (grazing area, area of vegetables, annual crop area and perennial crop area) in two seasons (rainy and dry season). To determine the seed bank, each environment was divided into four sub-areas of 0.2 hectares, considering that each area was a repetition, totaling 16 experimental units. Samples of 0.8 kg were taken from each area, and each sample was distributed on a plastic tray and allowed to germinate in a greenhouse. The density of the individuals was determined by observing the number of emerging seedlings in the trays, performing the counting at every 18 days. Evaluations were made for ninety days in each season. The germination curve was calculated, as well as the Shannon diversity index (H'), the Sorensen similarity index and the relative importance. The seven main species identified in the environments were Cyperus rotundus, Nicandra physaloides, Galinsoga parviflora, Alternanthera tenella, Panicum maximum, Portulaca oleracea and Eleusine indica. Among the studied environments, during the rainy season, the highest number of individuals was found in annual crop and the greatest diversity in the evergreen environment. During the dry season, the number and diversity of individuals were lower and similar in all environments.Keywords: rainy season, dry season, Shannon index, relative importance, diversity. Palavras-chave: estação das chuvas, estação da seca, índice de Shannon, importância relativa, diversidade. RESUMO -O banco de sementes é a reserva de sementes viáveis encontradas no solo e está relacionado à diversidade e abundância das espécies que compõem as populações de plantas daninhas. Com este estudo, objetivou-se determinar o banco de sementes em quatro ambientes distintos (área de pastagem, área de hortaliças, área de cultura anual e área de cultura perene), em duas épocas do ano (estação das chuvas e da seca

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Section: Resultsmentioning

confidence: 90%

Bank of Weed Seeds in Agrosystems in the Brazilian Cerrado

et al. 2016

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“…In Brazil, these species have been basically controlled through herbicide application (Ferreira et al, 2014). The herbicide aminopyralid + fluroxypyr, whose mechanism of action is to mimic auxin, interferes in the apical meristem of plants, thus affecting the division of tissues; it has been used in Brazil to control these weeds in pasture areas.…”

Section: Introductionmentioning

confidence: 99%

Does the Use of Adjuvants Alter Surface Tension and Contact Angle of Herbicide Spray Droplets on Leaves of Sida spp.?

2019

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Droplet spreading on plant surfaces may indicate greater efficiency in herbicide application. The aim of this study was to evaluate surface tension and contact angle of the aminopyralid + fluroxypir herbicide droplets associated with adjuvants on the leaf surface of three species of the genus Sida. The experiment was carried out in a completely randomized design, in a 4x2+1 factorial arrangement, with four replications. Four treatments containing two rates of the herbicide (0.04 + 0.08 kg a.i. ha-1 and 0.08+0.16 kg a.i. ha-1) were evaluated, associated or not with the adjuvants vegetable oil, mineral oil and lecthin; and water was used as a control. Surface tension and contact angle of the syringes were measured with a tensiometer. Surface tension was evaluated at 5, 15 and 25 seconds after droplet formation. Contact angle was measured at 5, 15 and 25 seconds after droplet deposition on the adaxial and abaxial surfaces of Sida rhombifolia, S. glaziovii and S. cordifolia. The results were submitted to analysis of variance by the F-test and the means of the treatments were compared by Tukey’s test (p>0.05). There was no interaction between the factors for surface tension. The contact angles of S. cordifolia and S. glaziovii were lower after addition of lecthin on the adaxial face. The addition of the adjuvants to the spray solution provided lower contact angles at the rate of 0.04 + 0.08 kg a.i. ha-1, except for S. rhombifolia, whose contact angle was lower with the spray solution without adjuvant.

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“…Similarly, changes in the composition of weed communities were also observed in different agricultural crops, such as sugarcane (Kuva et al, 2007;Soares et al, 2011), pastures (Ferreira et al, 2014), bean (Tavares et al, 2013), cover crops (Lima et al, 2014;Lamego et al, 2015), manioc (Cardoso et al, 2013;Soares et al, 2015), corn (Correa et al, 2011), corn intercropped with legumes (Oliveira et al, 2014) and corn intercropped with forage (Batista et al, 2014;Concenço et al, 2015), millet (Teodoro et al, 2015), lettuce (Ferreira et al, 2013), Jatropha curcas (Concenço et al, 2014) and coffee under organic management (Maciel et al, 2010a;Partelli et al, 2010).…”

Section: Cynodon Dactylon and Ipomoea Grandifoliamentioning

confidence: 89%

Weed community composition in different agro-systems

et al. 2017

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Weed communities in agricultural systems are diverse and subjected to different agronomic practices. In this study, a phytosociological survey of the weed community in different cropping systems consisting of corn, horticulture, perennial cultivation of Jatropha curcas and pasture of Urochloa brizantha in Rio Verde, GO, Brazil, was carried out. Assessments were performed at the beginning (October 2011) and at the end (March 2012) of the rainy season. After identifying and counting species, were calculated the phytosociological indices of density, frequency, abundance and relative importance, as well as the diversity index of Shannon-Wiener, evenness index of Pielou and similarity coefficient of Sorense. Were found 46 species of sixteen families, especially Poaceae. The most important species were: Alternanthera tenella in the annual growth environment during the both periods; Panicum maximum (early rainy season) and Chamaescy hirta (end of the rainy season) in the vegetable garden; Eleusine indica (early rainy season) and Galinsoga parviflora (end of the rainy season) in the perennial crop and Sida rhombifolia (early rainy season) and Neonotonia wigrtii (end of the rainy season) in the pasture. Lower diversity indices and evenness were observed in the pasture environment. Sampling time presented a higher impact on similarities when compared to the different environments.Keywords: Jatropha curcas, corn, pasture, no-tillage Composição florística de comunidades de plantas daninhas em diferentes agrossistemas ResumoComunidades de plantas daninhas em agrossistemas são diversificadas devido às práticas agronômicas adotadas. Neste trabalho realizou-se um levantamento fitossociológico em comunidade de plantas daninhas em diferentes sistemas de cultivo constituídos de cultivo de milho, olericultura, cultivo perene com pinhão-manso e pastagem de Urochloa brizantha, em Rio Verde, GO, no início (outubro de 2011) e no final (março de 2012) da época chuvosa. Após identificação e contagem das espécies calcularam-se os índices fitossociológicos: densidade, frequência, abundância e importância relativa, e os índices de diversidade de Shannon-Wiener e equitabilidade de Pielou e o coeficiente de similaridade de Sorense. Encontrou-se 46 espécies, distribuídas em dezesseis famílias, com destaque para Poaceae. As espécies mais importantes foram Alternanthera tenella no ambiente de cultivo anual em ambas as épocas; Panicum maximum (início da época chuvosa) e Chamaescy hirta (final da época chuvosa) em horta; Eleusine indica (início da época chuvosa) e Galinsoga parviflora (final da época chuvosa) em cultivo perene; e Sida rhombifolia (início da época chuvosa) e Neonotonia wigrtii (final da época chuvosa) em pastagem. Menores índices de diversidade e de equitabilidade foram observados em área de pastagem. Quanto às similaridades entre tratamentos, a época foi mais determinante do que os ambientes, considerando que as semelhanças entre ambientes foram maiores dentro da mesma época amostrada, exceto para a pastagem no final da es...

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Levantamento fitossociológico de plantas daninhas em pastagens degradadas do Médio Vale do Rio Doce, Minas Gerais

Cited by 21 publications

References 16 publications

Bank of Weed Seeds in Agrosystems in the Brazilian Cerrado

Bank of Weed Seeds in Agrosystems in the Brazilian Cerrado

Does the Use of Adjuvants Alter Surface Tension and Contact Angle of Herbicide Spray Droplets on Leaves of Sida spp.?

Weed community composition in different agro-systems

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