Brachiaria Decumbens Cv Research Articles

Forage mass, chemical composition and leaf chlorophyll index of signal grass and organic matter in soil under increasing levels of nitrogen

This study evaluated the forage mass, plant height, chemical composition and chlorophyll index of signal grass (Brachiaria decumbens cv. Basilisk), as well as the content of organic matter (OM) in soil under increasing levels of nitrogen. The experiment was conducted in the Rio Manso Farm, experimental unit of the Federal University of the Jequitinhonha and Mucuri Valleys - UFVJM in the municipality of Couto de Magalhães de Minas, state of Minas Gerais. For plant evaluation, we use a split plot randomized block design with four replications. Nitrogen levels (0, 25, 50, 75, 100 kg ha-1 N) were assigned to plots and the cuts made in plants, to subplots. For the assessment of soil organic matter, we used a split-split-plot, with nitrogen levels (0, 25, 50, 75 and 100 kg ha-1 by cut) in the plots, collection depth (0-10 and 10-20 cm) in the subplots and three sampling times (before the onset of the experiment, at the end of the 1st crop year and at the end of the 2nd crop year) in sub-subplots in a randomized block design with four replications. It can be concluded that nitrogen fertilization linearly increases forage mass, plant height and crude protein content of signal grass, which are positively correlated with chlorophyll index. At the end of two agricultural years, the content of organic matter in the soil decreases, which can be attributed to management of cutting and removal of the cut material.

Availability and toxicity of cadmium to forage grasses grown in contaminated soil

ABSTRACTIt is important to know the mechanisms for forage development, especially those related to the tolerance of potentially toxic elements, when considering their use in phytoremediation in heavy metal contaminated areas. In this study, we evaluated plant growth, concentration, and the availability of cadmium (Cd) for forage grasses (Panicum maximum Jacq. cv. Aruana and cv. Tanzânia; Brachiaria decumbens cv. Basilisk; Brachiaria brizantha cv. Xaraés and cv. Marandu) cultivated in Cd contaminated soils. The experiments were performed under greenhouse conditions over a 90-day evaluation period, and the Cd rates were 2, 4, and 12 mg/kg of soil. The relative growth rate of the forage grasses decreased as Cd rates increased, and the following descending order of susceptibility was observed: Marandu > Xaraés > Aruana > Tanzânia > Basilisk, with regard to phytotoxicity in these plants. The forage Cd concentration increased in line with increases in the Cd rates. Cd contents extracted by Mehlich-1 and by diethylenetriaminepentaacetic acid presented high positive correlation with forage relative growth. The forage plants did not block Cd entry into the food chain because they were not capable of limiting Cd absorption.

Perdas, perfil fermentativo e composição química das silagens de capim Brachiaria decumbens com inclusão de farelo de arroz

RESUMO Objetivou-se avaliar os efeitos do farelo de arroz sobre as perdas por gases e efluente, o perfil fermentativo e a composição química das silagens de Brachiaria decumbens cv. Basilisk ensilado em silos de laboratório. Utilizou-se delineamento inteiramente casualizado, com cinco tratamentos: 0; 10; 20, 30 e 40g/kg de farelo de arroz, com base na matéria natural da gramínea. Os valores das perdas por gases e efluentes foram reduzidos linearmente em 0,11 e 0,39g/kg MS, enquanto a recuperação da matéria seca aumentou linearmente em 0,32g/kg MS. Houve comportamento quadrático nos valores de pH e, redução linear para os valores de N-amoniacal e poder tampão, estimados em 1,1 e 0,5g/kg MS. As concentrações de ácido acético, butírico e propiônico foram reduzidas linearmente em 0,1; 0,008 e 0,006g/kg MS, enquanto a de ácido láctico aumentou linearmente em 0,5g/kg MS. Cada unidade porcentual de farelo de arroz promoveu aumento linear de 4,3; 1,8; 7,1 e 7,0g/kg nos teores de matéria seca, proteína bruta, extrato etéreo e nutrientes digestíveis totais, e redução linear de 6,9; 4,3 e 2,6g/kg MS nos teores de fibra em detergente neutro, fibra em detergente ácido e hemicelulose. A inclusão de 10g/kg de farelo de arroz já assegura diminuição das perdas por gases e efluentes, aumento na recuperação de matéria seca, proporcionando melhorias no perfil fermentativo e na composição química das silagens.

<b>Cattle production supplemented on signal grass pastures during the rainy season

The effects of four supplement doses (0, 1, 2 and 3 kg animal -1 day -1 ) on pasture characteristics and on cattle production on Brachiaria decumbens cv. Basilisk pastures in continuous stocking with variable stocking rate were assessed. Experimental design comprised completely randomized blocks with two replications. Concentrate supplementation did not influence mass (4141 kg ha -1 of DM) and production rate of forage (97.6 kg ha -1 day -1 of DM), morphological components and nutrition value in hand-plucked forage. Similarly, the number of live (1.607 tillers m - ²) and dead (636 tillers m - ²) tillers was not affected by concentrate supplementation. There were linear increases in animal performance (from 0.70 to 1.13 kg animal -1 day -1 ), stocking rate (1.9 to 3.8 animal unit ha -1 ) and animal production per area (1.8 to 6.2 kg ha -1 body weight) with supplementation doses. Concentrate supplementation does not change the structural characteristics of signal grass pastures managed in continuous stocking at 20 cm high, but increases animal production.

Consorciação e manejo de Brachiaria decumbens em mudas de cafeeiros infestados com Pratylenchus brachyurus em condições de casa de vegetação

Com o objetivo de avaliar o efeito da consorciação e manejo de Brachiaria decumbens cv. 'Basilisk' em cafeeiro (Coffea arabica cv. 'Catuaí Vermelho') infestado por Pratylenchus brachyurus (Pb), o presente experimento foi desenvolvido em condições de casa de vegetação. Os tratamentos utilizados, com cinco repetições, foram: 1. Café não inoculado no limpo; 2. Café não inoculado consorciado com B. decumbens; 3. Café inoculado com 5000 juvenis e adultos de Pb por vaso (10L), no limpo; 4. Café inoculado com Pb consorciado com B. decumbens podadas semanalmente; 5. Café inoculado com Pb consorciado com B. decumbens com aplicação do herbicida glifosato. Aos 3, 4, 7, 10 e 11 meses após transplante dos cafeeiros, houve um aumento significativo na altura das plantas de cafeeiro sem nematoide mantidas no limpo, comparadas com os tratamentos com cafeeiros em solo infestado com Pb consorciado com B. decumbens podadas e café em solo infestado com Pb consorciado com B. decumbens com aplicação de glifosato. Na avaliação final, realizada 278 dias após à inoculação das plantas, o peso da matéria seca da parte aérea nos tratamentos com Pb consorciado com braquiária e com aplicação de glifosato apresentaram menores valores, quando comparado com a testemunha sem nematoide e sem plantas consorciadas. Com relação ao peso da matéria fresca das raízes, todos os tratamentos foram significativamente mais baixos do que a testemunha sem nematoide e sem consorciação. A população final de P. brachyurus nas raízes foi maior quando o café foi consorciado com braquiária

Correlação entre o consumo e a deposição de ácidos graxos em bovinos suplementados com glicerina de baixa pureza em pastagens

<p>Objetivou-se determinar a correlação linear existente entre os ácidos graxos consumidos e depositados no músculo <em>Longissimus dorsi </em>de 35 bovinos machos não castrados, mestiços, com predominância da raça Nelore, com peso inicial médio de 428,0 ± 32,11 kg, terminados em pastagem de <em>Brachiaria decumbens </em>cv. Basilisk. O delineamento utilizado foi inteiramente casualizado, com cinco dietas e sete animais por dieta durante 74 dias. As dietas consistiram de níveis de inclusão da glicerina (0, 3, 6, 9 e 12%) na matéria seca (MS). Os animais foram pesados a cada 28 dias para avaliação do ganho de peso médio diário (GMD) e ajuste das dietas. Amostras do capim <em>Brachiaria decumbens</em>, dos suplementos, assim como do músculo <em>Longissimus dorsi </em>foram analisadas para avaliação do perfil de ácidos graxos. A correlação foi realizada estimando-se os coeficientes de correlação linear de Pearson. Os resultados encontrados demonstram a existência de correlações entre os ácidos graxos consumidos com aqueles depositados no músculo dos animais. As correlações observadas modificaram o perfil dos ácidos graxos da carne com redução da concentração dos ácidos graxos monoinsaturados e aumento da concentração dos ácidos graxos da série ? – 6, assim como da razão entre os ácidos graxos da série ? - 6 e ? - 3. Não foram verificadas correlações com os ácidos graxos hipercolesterêmicos (láurico, miristico e palmítico) do músculo dos bovinos suplementados com glicerina de baixa pureza.</p>

English

Thus study was conducted with the objective of evaluating production and forage characteristics of Signalgrass ( Brachiaria decumbens cv. Basilisk) deferred at different initial heights and nitrogen doses. Three initial sward heights (low - 10 cm, medium - 20 cm and high - 30 cm), three nitrogen doses (40, 80 and 120 kg/ha) and a control treatment, of no fertilization were evaluated. The experimental design utilized was of completely randomized blocks with three replications, in a subdivided-plot arrangement. There was no interaction between sward initial height and nitrogen dose for the variables analyzed. The Signalgrass deferred at an elevated initial height presented greater masses of forage, live stem, dead stem and dead leaves; higher percentage of dead stem and falling rate; and lower number of vegetative tillers, percentage of live leaves and live leaf/live stem ratio. Elevation in the nitrogen dose increase along with the number of live and vegetative tillers; masses of forage, live stem, dead stem, dead leaves and live leaves; percentage of live stem; and live tissue/dead tissue ratio; and reduced the percentage of dead leaves and the live leaf/live stem ratio. Signalgrass can be deferred at low and medium initial heights and varied nitrogen doses, according to the objectives and possibilities of the farmer.

Atributos químicos do solo, reservas orgânicas e sistema radicular de pastos degradados associada à introdução de leguminosa

The aim was to study the recovery of degraded pasture with the introduction of Stylosanthes macrocephala e capitata cv. Campo Grande on Brachiaria decumbens cv. Basilisk evaluating the levels N-total in roots, biomass, area, and length, diameter and root levels of macro and micronutrients in the soil. The experiment was conducted in the municipality of Andradina, Sao Paulo State, Brazil. The experimental design was a randomized block design in a split-plot (with and without phosphorus), with four replicates, forming the following treatments: control Brachiaria decumbens (CB), partial desiccation with 1.5 L ha-1 of glyphosate (DP), total desiccation with 3.0 L ha-1 of glyphosate (TD); tillage (T), soil scarification (S); harrowing rome (H) and plowing + disking (PD). Treatments H and PD were sown by broadcasting and the other in the form of direct seeding. Recovery strategies of grazing signal grass showed significant differences between treatments only for the content of N-total, there were no differences in geometric characteristics of roots and root biomass. The contents of macro and micronutrients in the soil showed no significant differences between the strategies of recovery. Fertilization had a significant effect for P. The introduction of estilosantes Campo Grande accompanied by techniques such as drying and plowing + disking contributed to increases in the N-total levels in the root system. Forms of introduction of legumes did not change the soil chemical properties.

<b> Initial height of pasture deferred and utilized in winter and tillering dynamics of signal grass during the following spring </b>

Tillering dynamics during regrowth in the spring (September to December 2009) on signal grass (Brachiaria decumbens cv. Basilisk) pastures deferred in the beginning of April 2009 is evaluated. Four pasture heights were evaluated at the beginning of deferment (10, 20, 30 and 40 cm). The experimental design consisted of completely randomized blocks with two replications. Rise in pasture height at the beginning of deferment decreased the appearance rate, increased the mortality rate and reduced the survival rate, the balance between appearance and mortality and the stability index of the tiller population at the beginning of the spring. Pastures deferred at initial height of 30 and 40 cm presented relatively stable tiller appearance rate between the beginning and end of spring. However, these pastures presented greater mortality rate, lower survival rate, lower balance between appearance and mortality and lower stability index of the tiller population at the beginning of spring when compared to rates at the end of spring. Pastures managed with shorter initial heights (10 and 20 cm) provided more tissue renewal in the subsequent growth season after their utilization in the winter.

Brachiaria species identification using imaging techniques based on fractal descriptors

The use of a rapid and accurate method in diagnosis and classification of species and/or cultivars of forage has practical relevance, scientific and trade in various areas of study, since it has broad representation in grazing from tropical regions. Nowadays it occupies about 90% of the grazing area along Brazil and, besides the grazing areas to feed ruminants, Brachiaria also corresponds to about 80% of seeds being traded in all the world, bringing a large amount of money to Brazil. To identify species and/or cultivars of this genus is of fundamental importance in the fields that produce seeds, to ensure varietal purity and the effectiveness of improvement programs. Thus, leaf samples of fodder plant species Brachiaria were previously identified, collected and scanned to be treated by means of artificial vision to make the database and be used in subsequent classifications. Forage crops used were: Brachiaria decumbens cv. IPEAN; Brachiaria ruziziensis Germain & Evrard; Brachiaria brizantha (Hochst. ex. A. Rich.) Stapf; Brachiaria arrecta (Hack.) Stent. and Brachiaria spp. The images were analyzed by the fractal descriptors method, where a set of measures are obtained from the values of the fractal dimension at different scales. Therefore such values are used as inputs for a state-of-the-art classifier, the Support Vector Machine, which finally discriminates the images according to the respective species. The proposed method outperforms other state-of-the-art image analysis methods and makes possible the correct prediction of species in more than 93% of the samples. Such remarkable result is consequence of the better suitability of representing complex structures like those arising in the plant leaves by measures of complexity from fractal geometry. Finally, this high correctness rate suggests that the fractal method is an important tool to help the botanist.

Physical properties of a Red-Yellow Latosol and productivity of a signalgrass pasture fertilized with increasing nitrogen doses

The physical properties and fertility of the soil are important factors in the formation and establishment of pasture. Changes in physical properties affect the movement of water, air, nutrients and roots, which, in turn, affect the productivity and longevity of pastures. The objective of this study was to evaluate the physical properties of the soil and the dry matter yield of a pasture with signalgrass cv. Basilisk (Brachiaria decumbens cv. Basilisk), fertilized with increasing nitrogen doses (N), on a dystrophic Red-Yellow Latosol. The experiment was conducted on the Fazenda Rio Manso of the Universidade Federal dos Vales do Jequitinhonha e Mucuri, in Couto de Magalhães de Minas, State of Minas Gerais, Brazil. To evaluate the annual forage yield, a split plot scheme in a randomized block design with four replications was used, with N doses (0, 50, 100, 150, and 200 kg/ha/year) in the plots and growing seasons (first and second) in the subplots. For soil evaluation, a split plot scheme was used with N doses (0, 25, 50, 75 and 100 kg/ha/cut) in the plots and three sampling times (prior to the experiment, at the end of the first growing season and at the end of the second growing season) in the subplots in a randomized block design with four replications. This analysis was performed separately at two soil depths (0-3 and 10-13 cm). Forage samples were analyzed for the annual dry matter yield (DMY), and soil samples were analyzed for pre-consolidation pressure (σp), initial soil bulk density (Bd), total pore volume (TPV) and void index (Vd). Higher nitrogen doses increased the dry matter yield of signalgrass pasture and the pre-consolidation pressure of the soil. The total pore volume and void index decreased, and the initial soil bulk density increased, though without promoting soil compaction.

Fungos e nematoides associados a sementes de forrageiras tropicais

Objetivou-se avaliar a incidência de fungos e nematoides em sementes de Brachiaria sp. e Panicum maximum produzidas nos estados de Mato Grosso do Sul (MS), Mato Grosso (MT), Goiás (GO), Minas Gerais (MG) e São Paulo (SP). Os principais fungos encontrados nas sementes foram Bipolaris sp., Curvularia sp. e Phoma sp.. As menores incidências destes fungos foram encontradas nas sementes das cultivares BRS Piatã e Xaraés de Brachiaria brizantha e Brachiaria decumbens cv. Basilisk, oriundas dos estados de GO, MG e MS, respectivamente. As cultivares Marandu e BRS Piatã, provenientes das várias regiões, apresentaram elevada ocorrência de Aphelenchoides sp. e Ditylenchus sp.. Sementes da cultivar Humidicola, de Brachiaria humidicola, produzidas em MS e SP, não apresentaram associação com nematoides. As sementes de Panicum maximum cv. Massai e cv. Mombaça apresentaram maiores incidências de Bipolaris sp., Cladosporium sp., Curvularia sp., Fusarium sp. e Phoma sp., bem como de Aphelenchoides sp. e Ditylenchus sp., especialmente nas sementes produzidas em MT. Alguns dos patógenos encontrados são agentes causais de doenças de grande importância em forrageiras, a exemplo de Bipolaris sp., causando a mancha foliar do Panicum, de alta severidade em Tanzânia, proporcionando sérios comprometimentos da sustentabilidade das pastagens.

<b>Defoliation patterns in signal grass tillers with varying heights in the same pasture</b> - doi: 10.4025/actascianimsci.v35i3.14376

The experiment was carried out to evaluate the patterns of defoliation in plants of various heights in the same pasture of Brachiaria decumbens cv. Basilisk under continuous stocking with cattle. Four plant heights were evaluated (10, 20, 30 and 40 cm) in the same managed sward, with mean height equal to 25 cm. A randomized blocks design was used, with two replications. Defoliation frequency increased linearly along with plant height in the same pasture. Defoliation intensity, number of defoliations in leaf blade and percentage of leaf blade grazed per tiller also increased linearly along with plant height. The defoliation interval decreased linearly according to plant height. The quadratic model was adequately fitted into grazing efficiency data, reaching the highest value (98%) at the sward site with 35 cm plants. The percentage variation in signal grass height showed a negative linear response with initial plant height. The structure of the pasture, characterized by the diversity in plant heights, is simultaneously the cause and consequence of the variability in defoliation patterns in individual tillers, which occur on the horizontal plane of the pasture.

Forage accumulation in brachiaria grass under continuous grazing with single or variable height during the seasons of the year

The objective of this study was to evaluate grazing management strategies of Brachiaria decumbens cv. Basilisk managed with different heights under continuous grazing with cattle. Two grazing management strategies were evaluated: maintenance of pasture with an average height of 25 cm throughout the experimental period and maintenance of pasture on the average of 15 cm in height during winter, up to 25 cm from the beginning of spring. The split-plot scheme and the randomized block design with four replications were adopted. The grazing management strategies corresponded to the primary factor, while the seasons (winter, spring and summer) corresponded to secondary factor. The reduction of the average sward height to 15 cm in the winter resulted, when compared with pasture maintained at 25 cm, in overall higher growth rates (95 kg/ha.day DM) and leaf blade (66.1 kg/ha.day DM), as well as higher rates of total accumulation (81.5 kg/ha.day DM) and leaf blade (52.6 kg/ha.day DM). The accumulated forage production (from winter to summer) was higher in the pasture lowered to 15 cm in winter (25.6 t/ha DM) compared with that managed with an average height of 25 cm (22.2 t/ha DM). Regarding the seasons of the year, in the winter, there were lower rates of overall growth (6.4 kg/ha.day DM), leaf blade (5.6 kg/ha.day DM) and pseudostem (0.8 kg/ha.day DM), and also lower total (-6.6 kg/ha.day DM) and leaf blade (-7.5 kg/ha.day DM) accumulation rates. In the spring there was a higher rate of leaf senescence (22.4 kg/ha.day DM). The accumulation of forage is incremented when the pasture of B. decumbens is lowered to 15 cm during the winter, and in the spring and summer, its average height is increased to 25 cm.

Signal grass structure at different sites of the same pasture under three grazing intensities

The experiment was conducted to evaluate Brachiaria decumbens cv. Basilisk at different sites of the same pasture featuring varying grazing intensities (under grazed, properly grazed and overgrazed). The pasture was managed under continuous stocking using 200-kg cattle and grass height kept at about 25 cm. The randomized block design was used, with three replications. Sward height (38.0 cm) and extended plant height (85.2 cm) were greater at the under grazed site. The falling index was lower at the properly grazed site (1.28). At the under grazed site, the masses of green leaf blade (3442 kg ha -1 DM), green stem (8370 kg ha -1 DM), green forage (11812 kg ha -1 DM) and total forage (14137 kg ha -1 DM) were higher when compared to the overgrazed and properly grazed sites. Dead material mass was higher at the properly grazed (3422 kg ha -1 DM) and under grazed (2324 kg ha -1 DM) sites. At the under grazed sites, there was a higher occurrence of tillers taller than 40 cm. Tillers with sizes between 10 and 30 cm predominated in properly grazed sites. In overgrazed site there was a higher share of tillers with sizes smaller than 20 cm. There is spatial variability of vegetation in the same pasture of Brachiaria decumbens cv. Basilisk due to uneven grazing by cattle.

Reciprocal recurrent selection in the breeding of Brachiaria decumbens

Pastures of Brachiaria decumbens cv. Basilisk radically changed the scenario of livestock production in central Brazil in the early 1970s and in fact, promoted the development of this vast region. However, despite the reasonable biomass yields and nutritional value when grown on these tropical acid soils, its susceptibility to grassland spittlebugs has limited its use. The breeding of B. decumbens in Brazil has been restricted to interspecific crosses using cv. Basilisk as a pollen donor due to the lack of compatible sexual ecotypes within this species. Recently, the successful chromosome duplication of a sexually reproducing diploid accession produced 3 successful events (Simioni and Valle 2009), enabling intraspecific crosses. This paper reports the onset of the research to obtain superior apomictic hybrids in B. decumbens using reciprocal recurrent selection (RRS), a cyclic breeding strategy.

Recovery of Trichostrongylus colubriformis infective larvae from three grass species contaminated in the autumn

This experiment aimed to assess the recovery of infective larvae (L3) of Trichostrongylus colubriformis from Brachiaria decumbens cv. Australiana, Cynodon dactylon cv. Coast-cross and Panicum maximum cv. Aruana. The experimental module comprised six plots, with two plots per herbage species. Larval survival was assessed from autumn to winter, under the effect of two herbage-paring heights (5 and 30 cm). TThe paring was carried out immediately before contamination with faces containing T. colubriformis eggs. The feces and herbage were collected at one, two, four, eight, 12 and 16 weeks after feces had been deposited in the experimental plots. In general, larvae were recovered from both herbage and feces until the 16th week. The longer persistence of these larvae in the environment was probably due to warmer temperatures. The number of L3 recovered from the pasture was not influenced by the height of plants, except for Brachiaria and Aruana herbage in the fourth week. Regarding the concentrations of larvae per kg of dry matter (L3/kg DM), recovery was higher from low pasture in all three herbage species. During the autumn, the development and survival of the T. colubriformis free-living stages were not affected by the different herbage species.

Rehabilitation with forage grasses of an area degraded by urban solid waste deposits

Dry matter yield and chemical composition of forage grasses harvested from an area degraded by urban solid waste deposits were evaluated. A split-plot scheme in a randomized block design with four replicates was used, with five grasses in the plots and three harvests in the subplots. The mineral content and extraction and heavy metal concentration were evaluated in the second cut, using a randomized block design with five grasses and four replicates. The grasses were Brachiaria decumbens cv. Basilisk, Brachiaria ruziziensis, Brachiaria brizantha cv. Marandu and cv. Xaraés, and Panicum maximum cv. Tanzânia, cut at 42 days of regrowth. The dry matter yield per cut reached 1,480 kg ha-1; the minimum crude protein content was 9.5% and the average neutral detergent fiber content was 62.3%. The dry matter yield of grasses was satisfactory, and may be an alternative for rehabilitating areas degraded by solid waste deposits. The concentration of heavy metals in the plants was below toxicity levels; the chemical composition was appropriate, except for phosphorus. The rehabilitated areas may therefore be used for grazing.

Armazenamento de sementes de braquiária peletizadas e tratadas com fungicida e inseticida

A qualidade de sementes é fundamental para o sucesso da formação de pastagem, de forma que é importante viabilizar tecnologias para elas. Assim, objetivou-se com este trabalho avaliar o desempenho de sementes de Brachiaria decumbens peletizadas e tratadas com fungicida e inseticida, durante o armazenamento. As sementes foram tratadas com thiabendazol na dosagem de 200mL 100kg-1 de sementes, com fipronil na dosagem de 500mL 100kg-1 de sementes e com a mistura de ambos (nas mesmas dosagens) e parte não foi submetida a esses tratamentos (testemunha). Posteriormente, as sementes foram peletizadas utilizando-se uma mistura de areia + microcelulose e cola Cascorex - PVA (20%), as quais em seguida foram armazenadas em condições ambientais em armazém convencional (temperatura e umidade relativa do ar média de 21,9°C e 68%, respectivamente), durante 12 meses. As sementes foram avaliadas inicialmente e a cada quatro meses com as seguintes avaliações: teor de água, teste de germinação, índice de velocidade de germinação, teste de emergência e índice de velocidade de emergência. A peletização das sementes de Brachiaria decumbens com areia e microcelulose prejudica a porcentagem e velocidade de germinação, bem como a emergência de plântulas durante o armazenamento. Sementes de Brachiaria decumbens cv. 'Basilisk' tratadas com fipronil, thiabendazol, ou com ambos, não devem ser armazenadas por mais de oito meses.

Capim-braquiária sob lotação contínua e com altura única ou variável durante as estações do ano: dinâmica do perfilhamento

Objetivou-se estabelecer estratégias de manejo do pastejo, sob lotação contínua, que otimizem o padrão natural de perfilhamento da Brachiaria decumbens cv. Basilisk. Duas estratégias de manejo do pastejo foram estudadas: em uma, o pasto foi mantido com 25 cm de altura média durante todo o período experimental; e na outra foi mantido em 15 cm de altura média durante o inverno, com aumento para 25 cm a partir do início da primavera. Adotou-se o esquema de parcelas subdivididas em delineamento em blocos casualizados com quatro repetições. Consideraram-se como fator primário as estratégias de manejo do pastejo, caracterizadas pelas alturas médias em que os pastos foram mantidos durante as estações do ano (inverno, primavera e verão) e, como fator secundário, as medidas ao longo do período experimental. A taxa de aparecimento de perfilho (4,7%), a taxa de mortalidade (4,7%) e o índice de estabilidade (0,998) foram menores no inverno. Nesta estação, contudo, a taxa de sobrevivência de perfilho foi maior (95,3%). Em comparação aos pastos mantidos com 25 cm, aqueles manejados com 15 cm de altura média no inverno apresentaram maiores taxas de aparecimento de perfilho (34,2%) e índice de estabilidade (1,065). O florescimento do capim-braquiária ocorreu apenas no verão e com pouca intensidade (0,5%). A otimização da renovação de perfilhos no pasto de B. decumbens cv. Basilisk sob lotação contínua ocorre com seu rebaixamento para 15 cm no início do inverno e seu posterior aumento para 25 cm no início da primavera.