Weeds alter the establishment of Brachiaria brizantha cv. Marandu

Abstract

Weeds alter the establishment of Brachiaria brizantha cv. Marandu Malezas afectan el establecimiento de AbstractThe present study evaluated the effects of different periods of coexistence among the main weeds and Marandu brachiaria grass (Brachiaria brizantha, now Urochloa brizantha) in newly sown pasture. The experiment was conducted in a randomized block with 4 replications, with treatments being 8 coexistence periods: 0, 15, 30, 45, 60, 75, 90 and 120 days after emergence. A phytosociological assessment of the weed community was carried out at the end of the coexistence periods, and weeds were eliminated from the appropriate treatment using herbicide. Key morphogenic parameters of the forages were assessed at the end of the experimental period and dry matter production was determined. Results indicated that the presence of weeds had negative impacts on the main morphogenic components, such as plant height, number of tillers and production of leaf and stem dry matter. The presence of weeds reduced productivity in Marandu, with 15 days competition being sufficient to reduce forage production by approximately 50%, suggesting that weed control measures should be adopted within 15 days following emergence of seedlings of Marandu and weeds.Keywords: Dry matter, interference, pasture renovation, weed competition. ResumenEn un latosol localizado en Sinop, Mato Grosso, Brasil se evaluaron los efectos de la infestación de las principales malezas de la zona (Hyptis suaveolens, Senna obtusifolia y Sida rhombifolia), en diferentes edades después de la siembra, en la producción y algunas características morfogénicas de la gramínea forrajera Brachiaria brizantha (ahora: Urochloa brizantha) cv. Marandu. Los tratamientos fueron dispuestos en un delineamiento experimental de bloques al azar con 4 repeticiones y consistieron en los períodos de convivencia: 0, 15, 30, 45, 60, 75, 90 y 120 días después de la emergencia de la gramínea. Al finalizar cada uno de estos períodos se realizó una evaluación fitosociológica de la comunidad infestante y se eliminaron las malezas utilizando un herbicida. Al término del período experimental se evaluaron los principales parámetros morfogénicos del pasto, así como la producción de materia seca. Los resultados mostraron un efecto negativo de las malezas en la altura de planta y el número de rebrotes, así como en la producción de materia seca de hojas y tallos. La presencia de las malezas redujo la producción del pasto en todos los tratamientos, variando de 50% (competencia durante los primeros 15 días) hasta 74% (120 días). Por tanto las medidas de control de las malezas deben ser adoptadas durante las 2 primeras semanas de convivencia con el pasto Marandu.Palabras clave: Competencia, interferencia, materia seca, renovación de pasturas.

Potential of methane and carbon dioxide in vitro production by Urochloa hybrid subjected to periods of coexistence with weeds

“…It´s noted that the grasses of the genus Urochloa (syn. Brachiaria) are among the exotic forages currently cultivated in Brazilian pastures due to their adaptation to the most adverse climatic and soil conditions, dominating widely on the other genera of forages used in the Cerrado environment (MARCHI et al, 2017).…”

“…The main problem caused by weeds is the direct competition for space, light, water, and nutrients, causing a reduction of the physiological reserves of forages (SANTOS et al, 2011). When competing for growth factors, weeds can also provide decreases in the nutritional value and pasture support capacity, provide an increase in the time of pasture formation and recovery, cause injury and/or intoxication to animals, and compromise the aesthetics of the property (MARCHI et al, 2017;BELLÉ et al, 2018;MARCHI et al, 2019).…”

“…Considering that gas production varies according to the quantity and quality of the food ingested by the animal and that weeds can influence these two characteristics of tropical forages (MARCHI et al, 2017;BELLÉ et al, 2018;LOURENÇO et al, 2019), this research aimed to study the interference relationships of weeds on productive components, nutritional quality, energy potential, and production potential of GHG by the Convert HD364 grass under pasture renovation conditions.…”

Pyricularia pennisetigena and P. zingibericola from invasive grasses infect signal grass, barley and wheat

“…), rye (Secale cereal), barley (Hordeum vulgare), maize (Zea mays) and wheat (Triticum aestivum) (Bailey & Eijnatten 1961, Igarashi et al 1986, Urashima et al 1993 ABSTRACT RESUMO al. 1996, Couch & Kohn 2002, Goulart et al 2003, Couch et al 2005, Marchi et al 2005. The adoption of the Pyricularia oryzae designation as the species associated with blast disease is recent.…”

“…The adoption of the Pyricularia oryzae designation as the species associated with blast disease is recent. Until the early 2000s, Pyricularia grisea was considered the pathogen of blast disease on rice, signal grass, barley and wheat (Urashima et al 1993, Marchi et al 2005. A molecular phylogenetic reclassification proposed by Couch & Kohn (2002) showed that P. grisea was exclusively associated with blast disease on grasses from the Digitaria genus, whereas P. oryzae was associated with rice, wheat and other cultivated grasses or invasive plants (e.g.…”