scholarly journals Period of Weed Interference in Guarana Crop

2019 ◽  
Vol 37 ◽  
Author(s):  
D.O.P. SOARES ◽  
S.M.F. ALBERTINO ◽  
F.C.P. SOUZA ◽  
A.F. SANTOS ◽  
J.F. SILVA
Keyword(s):  
Urban Areas ◽  
Block Design ◽  
Limiting Factor ◽  
Weed Species ◽  
Importance Value Index ◽  
Importance Value ◽  
Rural And Urban Areas ◽  
Weed Interference ◽  
Randomized Block Design ◽  
Four Blocks

ABSTRACT: Guarana is a plant native to the Amazon region that produces the fruit known as guarana. Guarana production is carried out by small farmers and is a source of income for thousands of people in rural and urban areas. The interference caused by the competition between weeds and guarana is an important limiting factor of its production. Despite its economic and social importance, there are few studies on the management of weeds in this species. Thus, this research aimed to study the effects of weed interference on guarana yield in different periods. This study was performed in Maués, AM, in the 2014 and 2015 seasons. The experimental design was a randomized block design with eight treatments and four blocks. Treatments consisted of a combination of four different periods of control or coexistence with weeds (March to May, June to August, September to November, and December to February). Weed community was composed of 23 weed species belonging to 12 botanical families, with Paspalum virgatum being the species with the highest importance value index (55.74%). Weed coexistence with guarana from June to August provided the lowest yields (156.16 kg ha-1 of grains) when compared to weed control in the same period (309.05 kg ha-1 of grains). Weed interference from June to August reduced guarana yield by 50%.

scholarly journals DINÂMICA POPULACIONAL DE PLANTAS DANINHAS EM ÁREAS COM SORGO SACARINO E GRANÍFERO COM DIFERENTES ESPAÇAMENTOS E DENSIDADES DE SEMEADURA

2018 ◽  
Vol 17 (3) ◽  
pp. 390
Author(s):  
TALITA CAMARGOS GOMES ◽  
DÉCIO KARAM
Keyword(s):  
Sorghum Bicolor ◽  
Sweet Sorghum ◽  
Block Design ◽  
Crop Management ◽  
Dry Mass ◽  
Grain Sorghum ◽  
Weed Species ◽  
Importance Value Index ◽  
Importance Value ◽  
Randomized Block Design

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.

scholarly journals Weed Occurrence in Sugarcane as Function of Variety and Ground Straw Management1

2016 ◽  
Vol 34 (2) ◽  
pp. 219-228 ◽  
Author(s):  
G. CONCENÇO ◽  
J.R.A. LEME FILHO ◽  
C.J. SILVA ◽  
R.F. MARQUES ◽  
L.B.X. SILVA ◽  
...  
Keyword(s):  
Cultural Practices ◽  
Soil Seed Bank ◽  
Block Design ◽  
Weed Species ◽  
Leaf Architecture ◽  
Importance Value ◽  
Randomized Block Design ◽  
Infestation Density ◽  
Second Year ◽  
Occurrence Of Species

ABSTRACT This study aims to verify the effect of crop varietal architecture and straw removal from planting rows in the occurrence of weeds in sugarcane and infer about the sustainability of the production system with no herbicide application. The experiment was established in 2011 in a randomized block design with split plots and four replications. Main plots were varieties IACSP95 5000 and SP91 1049. In the sub-plots there the straw removal was allocated (evenly scattered in the area, or concentrated in inter-rows). Assessments were conducted in 2012 and 2013 and the absolute levels of infestation, density, frequency and dominance of weed species were obtained. Areas were intra-characterized by the coefficients of Simpson and Shannon-Weiner and sustainability inferred by the SEP coefficient. Areas were grouped by the similarity coefficient of Jaccard. Other factors besides leaf architecture were more significant for level of infestation. Treatments with straw removal from planting rows were more infested than those with evenly scattered straw. In the second year of cultivation, those species most adapted to the system increased their importance value. Wild poinsettia was the dominant weed in all treatments, deserving attention from pre-planting on, to reducing its occurrence in the soil seed bank. Species diversity was higher where straw was evenly scattered due to the occurrence of species other than wild poinsettia. Sustainability was reduced from the first to the second year, indicating that only cultural practices are not enough, even with high shading provided by crop and straw production, demanding herbicides.

scholarly journals EFFECTS OF COMPETITION AND WATER DEFICIENCY ON SUNFLOWER AND WEED GROWTH

2019 ◽  
Vol 32 (2) ◽  
pp. 318-328 ◽  
Author(s):  
MURILO MEIRA SOARES ◽  
CLÁUDIA DAIANNY MELO FREITAS ◽  
FERNANDO SARMENTO DE OLIVEIRA ◽  
HÉLIDA CAMPOS DE MESQUITA ◽  
TATIANE SEVERO SILVA ◽  
...  
Keyword(s):  
Water Deficit ◽  
Block Design ◽  
Dry Mass ◽  
Co2 Assimilation ◽  
Water Deficiency ◽  
Weed Species ◽  
Negative Effects ◽  
Weed Interference ◽  
Weed Growth ◽  
Randomized Block Design

ABSTRACT In the agricultural environment, the occurrence of biotic and abiotic stresses, such as weed interference and soil water deficit is common. However, little is known about the effects of the interaction of these stresses on the growth of cultivated crops and weed species. Thus, the objective of this study was to evaluate the effects of competition and water deficiency on the growth of sunflowers and weeds. The experiment was performed in a randomized block design with four replications. The treatments were arranged in a 5 × 2 factorial design, with the first factor corresponding to the competition arrangements between the species (sunflower + Waltheria indica; sunflower + Amaranthus spinosus; and sunflower, W. indica, and A. spinosus in monoculture without competition) and the second factor corresponding to water regimes (irrigated and water deficit). The water deficit regime was established when the sunflower plants had six expanded leaves (V6 stage) and was maintained until the rate of CO2 assimilation of the plants reached values close to zero (6 days), after which irrigation was resumed and maintained until 40 days after emergence, when the plants were collected and evaluated. The growth components evaluated were plant height, leaf area, dry leaf mass, dry stem mass, dry root mass, and total dry mass. Competition between plants decreased sunflower, W. indica, and A. spinosus growth. W. indica and A. spinosus aggravated the negative effects of water deficiency on sunflower growth. The water deficit regime did not affect the growth of W. indica. A. spinosus was more competitive with the sunflower than was W. indica.

Caracterização da Peneira Média em Clones de Coffea canephora

REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Block Design ◽  
Coffea Canephora ◽  
Coffee Production ◽  
Randomized Block Design ◽  
Significant Difference ◽  
The Mean ◽  
Four Blocks ◽  
Selection Of

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.

scholarly journals PHYSICAL AND PHYSIOLOGICAL ATTRIBUTES OF NATIVE FOREST SEEDS AND THEIR INFLUENCE ON DIRECT SEEDING FOR RESTORATION OF CILIARY FOREST

FLORESTA ◽  
2021 ◽  
Vol 51 (2) ◽  
pp. 255
Author(s):  
Janisson Batista de Jesus ◽  
Robério Anastácio Ferreira ◽  
Dráuzio Correia Gama ◽  
Maria Fernanda Oliveira Torres
Keyword(s):  
Block Design ◽  
Riparian Forests ◽  
Direct Seeding ◽  
Native Forest ◽  
Morphometric Characteristics ◽  
Randomized Block Design ◽  
Successful Recovery ◽  
Physiological Attributes ◽  
Four Blocks ◽  
Forest Seeds

Knowing the relationship between the physical and physiological characteristics of native forest seeds is essential for the successful recovery of riparian forests. Thus, the work was carried out to analyze the physical and physiological parameters of seeds of native forest species for use in the recovery of riparian forests by direct seeding. Were evaluated the physical quality (water content, mass, the weight of one thousand seeds, and the number of seeds per kilogram), morphometric characteristics (length, width, and thickness), and physiological quality in the laboratory (viability) of Cassia grandis L.f., Enterolobium contortisiliquum (Vell.) Morong., Guazuma ulmifolia Lam., and Libidibia ferrea var. leiostachya (Benth.) LPQueiroz. The experiment in the field was implanted in a randomized block design (RBD) with four blocks, testing seeds treated to overcome the four species dormancy. The direct sowing was in 10 planting lines, each composed of 10 pits (30 x 30 x 30 cm), spaced 2.0 x 1.0 m. E. contortisiliquum seeds, despite having the highest values for physical and morphometric characteristics, and having a high percentage of germination, was the species with the lowest percentage of emergence in the field, being below G. ulmifolia, which has seeds of smaller size and weight, and L. ferrea var. leiostachya which, despite having low germination, was the second with the highest percentage of emergence. The study allowed us to observe that there was no direct relationship between the physical and physiological attributes of forest seeds and their ability to emerge.

scholarly journals Growth and Gas Exchange of Cucurbita pepo L. Under Nitrogen and Silicon Fertilization

2019 ◽  
Vol 11 (9) ◽  
pp. 83
Author(s):  
Jackson de M. Alves ◽  
Alex S. de Lima ◽  
Cesenildo de F. Suassuna ◽  
Francisco R. A. Figueiredo ◽  
Toshik Iarley da Silva ◽  
...  
Keyword(s):  
Cucurbita Pepo ◽  
Polynomial Regression ◽  
Foliar Application ◽  
Growth Parameters ◽  
Block Design ◽  
Limiting Factor ◽  
Simultaneous Application ◽  
Gas Exchanges ◽  
Nitrogen Levels ◽  
Randomized Block Design

Zucchini (Cucurbita pepo L.) is a horticultural crop of great socioeconomic importance in Brazil and in the world. However, inappropriate fertilization management, such as over-fertilization of soils, may become a limiting factor for its development. Thus, the aim of this study was to evaluate the morpho-physiological behavior of zucchini submitted to nitrogen (N) doses applied via soil and foliar application of silicon (Si). The treatments were distributed in split-plot scheme in a randomized block design, with three replications. The plot was formed by silicon levels (0.0 and 6.0 g plant-1) and the subplots constituted by five nitrogen levels (30, 60, 90, 120 and 150 kg ha-1), adding up to 30 experimental units. Gas exchanges and growth parameters were assessed at 35 days after planting. The data were submitted to analysis of variance by the F test and in the cases of significance was performed a polynomial regression analysis for the nitrogen factor and Tukey test for the silicon factor. The supply of Si positively enhances the effects of N on growth characteristics and gas exchanges of zucchini. The simultaneous application of Si and N does not influence the leaf area of zucchini. The N dose of 93.9 kg ha-1 provides greater assimilation of CO2 in zucchini plants under the conditions in which the experiment was performed.

scholarly journals Yield and technological performance of sugarcane cultivars grown under Af climate conditions

2020 ◽  
Vol 41 (1) ◽  
pp. 73
Author(s):  
Augusto Sousa Miranda ◽  
Felipe Nogueira Domingues ◽  
Bruno Spacek Godoy ◽  
Aníbal Coutinho do Rêgo ◽  
Cristian Faturi ◽  
...  
Keyword(s):  
Reducing Sugars ◽  
Agronomic Traits ◽  
Block Design ◽  
High Yield ◽  
Technological Parameters ◽  
Climate Conditions ◽  
Sugarcane Crop ◽  
Randomized Block Design ◽  
Four Blocks ◽  
Almost All

Sugarcane crops are grown in almost all regions of Brazil, in various types of soil and under the influence of different climate conditions, which results in diverse production environments as climate factors directly influence the yield and technological quality of a sugarcane crop. The present study evaluated the agronomic and technological characteristics of sugarcane cultivars grown in Af climate conditions. The agronomic traits (natural matter production and the number, length, and diameter of stalks) and technological attributes (Brix, purity, Pol, reducing sugars, total reducing sugars, moisture, and fiber content) of three sugarcane cultivars, IACSP93-6006, RB83-5486, and SP79-1011, were determined in a three-year experiment with a randomized block design using four blocks and two repetitions per block. The cultivars IACSP93-6006 and SP79-1011 exhibited superior agronomic traits compared to RB83-5486, showing better adaptation to the soil and climate conditions of the study area. However, the technological attributes, which were below the minimum standard levels required by the sugar and ethanol industry, were not statistically different among the studied cultivars. The abundant rainfall and high temperatures, characteristics of an Af climate, were not favorable for sucrose accumulation in the IACSP93-6006, RB83-5486, and SP79-1011 cultivars. Therefore, despite the high yield, sugarcane intended for industrial purposes should not be grown under Af climate conditions, owing to the insufficient technological parameters.

scholarly journals Interference Periods in Soybean Crop as Affected by Emergence Times of Weeds

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.R. ZANDONÁ ◽  
D. AGOSTINETTO ◽  
B.M. SILVA ◽  
Q. RUCHEL ◽  
D.S. FRAGA
Keyword(s):  
Weed Management ◽  
Critical Period ◽  
Block Design ◽  
Crop Productivity ◽  
Dry Mass ◽  
Weed Interference ◽  
Randomized Block Design ◽  
Intermediate Time ◽  
Crop Cycle ◽  
Weed Emergence

ABSTRACT: Weeds emergence times modify competition with crops. Thus, the hypothesis was that the increase in weed emergence flow decreases the period prior to interference (PPI) in soybeans and increases the critical period of interference prevention (CPIP). The objective was to determine the PPI and the CPIP of weeds in soybean crops as affected by the preferred time of weeds emergence flow. Three experiments were conducted in the field in a randomized block design with four replications. The treatments were arranged in a factorial design with factor A consisting of coexistence or weed control in soybeans and factor B for eight periods (0, 7, 14, 21, 28, 35, 42 and 135 days after crop emergence (DAE)). The numbers of emerged plants and weed dry mass by genus and crop productivity were evaluated. The weed interference in culture during all the crop cycle reduces the soybean average yield 73, 94 and 89% in the first, second and third sowing times, respectively. Chemical control may be adopted at the end of PPI, which must be done at 14, 15 and 5 DAE crop, for the first, second, third times, respectively. The sowing in advance and intermediate time of recommendation increase the PPI in about 10 days, favoring the weed management in soybean crops.

scholarly journals Phytosociology in Degraded and Renewed Pastures in Agrosilvopastoral Systems

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.

scholarly journals Economic Feasibility of Chemical Weed Control in Soybean Production in Serbia

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 291 ◽  
Author(s):  
Maja Meseldžija ◽  
Miloš Rajković ◽  
Milica Dudić ◽  
Milica Vranešević ◽  
Atila Bezdan ◽  
...  
Keyword(s):  
Weed Control ◽  
Block Design ◽  
Economic Feasibility ◽  
Economic Injury Level ◽  
Weed Species ◽  
Soybean Crop ◽  
Economic Justification ◽  
Randomized Block Design ◽  
Effective Combination ◽  
Economic Injury

The aim of this study was to investigate the efficacy and phytotoxicity of herbicides in combinations and to determine their economic feasibility in the soybean crop. The trials were placed at two locations, Pobeda and Budisava (Serbia), during 2016 and 2018, organized in a randomized block design with four replicates of all herbicide combinations (metribuzin + S-metolachlor; imazamox + oxasulfuron + typhenesulfuron-methyl; metribuzin + S-metolachlor + imazamox + oxasulfuron + typhenesulfuron-methyl; and bentazon + imazamox + typhenesulfuron-methyl). At the first location, 16 weed species were determined, while in the second location, 14 were determined. The highest reduction in the number of weeds was achieved at the first location, using a combination of herbicides metribuzin + S-metolachlor + imazamox + oxasulfuron + typhenesulfuron-methyl with a total efficacy that ranged from 96.98% to 97.40%. Only on the second location bentazone + imazamox + tifensulfuron-methyl showed passable phytotoxicity on soybean, during both years. Based on the established economic justification, in the combinations of metribuzin + S-metolachlor + imazamox + oxasulfuron + typhenesulfuron-methyl, yield was increased for 2350 kg/ha or 1.91 times more, according to the untreated variant at first location. The economic injury level at the most effective combination of herbicides was 52.70 weeds/m2.

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