Características morfogênicas e estruturais de Trachypogon plumosus de acordo com a fertilidade do solo e o nível de desfolha

Silveira

Compost Science & Utilization

et al. 2018

The use of organic compost in pasture fertilization is a form of recycling nutrients contained in waste and reducing chemical fertilizer use. To perform pasture fertilization, however, grass responses to doses of organic composts must be known. Thus, the objective of this study was to find the best dose of laying hen organic compost to maximize the productive, morphogenetic, structural, and nutritional responses of Paiagu as and Piatã grasses. A completely randomized factorial (4 £ 2) design was used, composed of organic compost doses (0, 400, 800, and 1,200 kg equivalent N.ha ¡1) and two cultivars (Piatã and Paiagu as) of Urochloa brizantha grass with three replicates per treatment, assessed during four successive cuts. The parameters evaluated were dry matter yield (DM) of shoots and roots, leaf appearance rate (LAR), leaf elongation rate (LER), phyllochron, pseudoculm elongation rate (PER), final leaf length (FLL), number of green leaves (NGL), and senescence rate (SR). The nutritional value of the grasses was also assessed through contents of dry matter, organic matter, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber, cellulose, hemicellulose, lignin, and in vitro organic matter digestibility (IVOMD). DM yields of both shoot and root increased due to nitrogen increase and Paiagu as grass had the highest yields (P < 0.01). The best organic compost doses ranged from 640 to 950 kg of equivalent N.ha ¡1 for most morphogenic and structural grass characteristics. The chemical composition of grasses was not influenced (P > 0.05) by doses of organic compost. Levels of 8.05% CP, 67.10% NDF, and 65.14% IVOMD were observed for cultivar Paiagu as, while for cultivar Piatã these values were 7.58% CP, 70.32% NDF, and 63.38% IVOMD. It is concluded that high doses of an organic compost are required (in equivalent N) for cultivars to reach the highest growth rates and that Paiagu as grass has higher dry matter yield, higher growth rates, and better chemical composition when compared to Piatã grass in similar organic fertilization conditions.

Section: Resultsmentioning

confidence: 99%

Use of Organic Compost for the Fertilization of Piatã and Paiaguás Grasses: Effects of Dose on Morphogenetic, Structural, Nutritional, and Productive Characteristics

Silveira

Compost Science & Utilization

et al. 2018

“…In the native area, the highest relative frequencies (Frr) were observed for the species T. plumosus (40.92%), Bulbostylis capillaris (18.52%), and Spermacoce capitata (18.33%) ( Table 3). According to Costa et al (2013), T. plumosus were observed with great representativeness in an area of native pastures of the Cerrado of Roraima, with around 80% of its botanical composition. Studies have shown that forage yield of T. plumosus is variable and directly influenced by management practices and environmental conditions (Costa et al, 2011(Costa et al, , 2013(Costa et al, , 2014.…”

Section: Resultsmentioning

confidence: 99%

Occurrence of Weeds in Areas Submitted to Tillage Managements for Soybean Cultivation in the Cerrado of Roraima

et al. 2019

Weeds from soils submitted to different tillage managements were identified in two consecutive years of soybean cultivation in the Cerrado of Roraima. The study was carried out in three areas: native area (NA), mechanically mowed native area (MA), and limed area (LA). A descriptive analysis of the phytosociological parameters relative density (Drr), relative frequency (Frr), relative dominance (Dor), importance value index (IVI), and index of relative importance (IRI) was performed to interpret the results. The weed similarity index (SI) was also calculated in the assessed areas. The highest relative frequencies were observed for Trachypogon plumosus (40.92%), Bulbostylis capillaris (18.52%), and Spermacoce capitata (18.33%) in the native area and T. plumosus (24.69%), Cyperus flavus (24.69%), and S. capitata (18.52%) in the mowed area. Among the species collected in the areas, the botanical families Poaceae, Cyperaceae, Fabaceae, and Rubiaceae are the most representative. The used managements contribute to the emergence of new species of spontaneous plants and weeds in the Cerrado of Roraima.

“…Segundo Costa et al (2011), em área de pastagens nativas das savanas de Roraima, o capim T. plumosus aparece com grande representatividade, entre 70 e 90% da composição botânica. Estudos têm mostrado que o rendimento de forragem de T. plumosus é variável e diretamente influenciado pelas práticas de manejo impostas e condições ambientais (COSTA et al, 2011;COSTA et al, 2013).…”

Section: Discussionunclassified

Ocorrência De Plantas Daninhas Na Cultura Do Feijão-Caupi Sob Quatro Manejos Na Amazônia Ocidental

Teixeira

Alves

Albuquerque

et al. 2020

NAT

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.