Abstract The purpose of this study was to examine the growth and senescence dynamics of Digitaria eriantha cv. Survenola as a response to several canopy heights (25, 35, 45, and 55 cm) of harvests in two seasons of the year (rainy and dry). The experiment was established at the Federal University of Sergipe, in São Cristóvão - SE, Brazil, from 03/26/2015 to 03/28/2016, under a randomized-complete-block design with four replicates. Plots were irrigated, and upon reaching the pre-established canopy heights, they were cut to a 10 cm-residual height. Increasing canopy heights in the dry season led to lower tiller density, for basal and aerial tillers. However, irrespective of tiller type and season, this variable increased after the rest period. Light interception rose with canopy heights (P<0.05) in the dry period and it showed a quadratic response in the rainy season. Greater canopy heights led to a higher (P<0.05) daily leaf senescence rates and daily stem growth rates. Regardless of the season, the total accumulation and net herbage accumulation rates of basal tillers increased as canopy heights did. The greatest canopy height promoted the daily stem production, whereas the lowest height did not allow the grass to express its production potential. The defoliation-height range of 35 to 45 cm is the most recommended, as it favors the control of stem growth and leaf senescence.

Resumen El objetivo del estudio fue conocer la dinámica del crecimiento y senescencia del forraje de Digitaria eriantha Steud. cultivar Survenola al alcanzar diferentes alturas de corte (25, 35, 45 y 55 cm), en dos épocas del año (lluvias y seca). El experimento se condujo en la Universidad Federal de Sergipe, en San Cristóbal-Sergipe, entre el 26/03/2015 y el 28/03/2016, con un diseño de bloques completos aleatorizados y cuatro repeticiones. Las unidades experimentales fueron irrigadas, y al alcanzar las plantas las alturas preestablecidas, se cortaron a 10 cm sobre el nivel del suelo. Las dos alturas de rebrote mayores redujeron en la época seca la densidad poblacional de tallos basales y aéreos; sin embargo, independientemente del tipo de tallo y la época del año, la densidad de población de tallos aumentó durante el período de descanso. La intercepción de luz en la época seca se incrementó (P<0.05) en las alturas de corte mayores, y en la época de lluvias su comportamiento fue cuadrático. Las alturas de corte mayores aumentaron (P<0.05) la tasa diaria de senescencia de las hojas y la tasa diaria de crecimiento de los tallos basales y aéreos. Las tasas de acumulación total y acumulación neta de forraje de tallos basales, independientemente de las épocas, tuvieron una relación positiva con el incremento en las alturas de corte. La mayor altura de corte produjo la mayor producción diaria de los tallos; además, la menor altura de corte no permitió a la gramínea expresar su potencial productivo. El intervalo de defoliación entre las alturas de 35 a 45 cm es el más indicado, pues favorece el control en el crecimiento del tallo y la senescencia de las hojas.

Resumo Foram avaliados os efeitos de doses de suplemento (0, 1, 2 e 3 kg animal-1 dia-1) e períodos de pastejos (1, 28, 59, 89 e 103 dias) sobre a estrutura da Brachiaria decumbens cv. Basilisk e a produção de bovinos em pastagens diferidas. O delineamento foi em blocos casualizados com duas repetições. A altura do pasto e as massas de forragem total e de colmo diminuíram com o período de pastejo. A proteína bruta (8,12%) e a digestibilidade in vitro da matéria orgânica (52,74%) não foram influenciadas pelo período de pastejo. Os teores de fibras em detergente neutro e ácido aumentaram linearmente com o período de pastejo. O ganho médio diário dos bovinos variou de 0,419 a 1,019 kg animal-1 dia-1; a taxa de lotação variou de 2,7 a 3,9 UA ha-1; e o ganho médio por área variou de 2,7 a 7,9 kg ha-1 dia-1, sendo os maiores valores obtidos com a dose mais alta de concentrado. A suplementação com concentrado aumenta a produção de bovinos em pastagens diferidas. Durante a utilização do pasto diferido no inverno há decréscimos na quantidade e na qualidade da forragem, bem como limitação em sua estrutura.

Abstract The effects of supplement doses (0, 1, 2 and 3 kg ha-1 day-1) and grazing periods (1, 28, 59, 89 and 103 days) on the B. decumbens cv. Basilisk structure and cattle production in deferred pastures were evaluated. The design was a randomised complete block design with two replications. The sward height and the total forage and stem masses decreased with grazing period. The crude protein (8.12%) and in vitro organic matter digestibility (52.74%) were not affected by grazing period. The fibre content in neutral and acid detergent increased linearly with the grazing period. The average daily gain of cattle ranged from 0.419 to 1.019 kg animal-1 day-1; the stocking rate ranged from 2.7 to 3.9 animal unit ha-1; and the average gain per area ranged from 2.7 to 7.9 kg ha-1 day-1, with the maximum values obtained with the highest dose of concentrate. Concentrate supplementation increases cattle production in deferred pastures. During the use of deferred pasture in winter there are decreases in the quantity and quality of forage, as well as limitations in its structure.

Resumo Este trabalho foi desenvolvido de 25 de fevereiro a 01 de julho de 2012 para recomendar a(s) dose(s) de nitrogênio e o(s) período(s) de diferimento que resultam em pastos diferidos de Brachiaria brizantha cv. Piatã (capim-piatã) com características estruturais adequadas ao consumo animal. Foram avaliadas combinações entre períodos de diferimento e condições de adubação nitrogenada. Os períodos de diferimento foram longo (127 dias) e curto (79 dias). As doses de nitrogênio foram de 0, 40, 80 e 120 kg/ha. O delineamento experimental foi de blocos casualizados, com três repetições. O índice de área foliar (IAF) e a interceptação luminosa (IL) aumentaram com a aplicação de nitrogênio. Na ausência ou dose pequena de nitrogênio, o pasto diferido por curto período apresentou IAF e IL inferiores ao manejado com longo período de diferimento. A dose de nitrogênio só influenciou a densidade de perfilhos basais vegetativos. O menor período de diferimento resultou em maiores números de perfilhos basais e aéreos vegetativos, assim como número inferior de perfilho basal reprodutivo. O nitrogênio aumentou o comprimento da lâmina foliar e do colmo do perfilho vegetativo. Longo período de diferimento resultou em colmo e lâmina foliar mais compridos e maior número de folhas mortas. O capim-piatã pode ser diferido por 80 dias, com aplicação de 80 kg/ha de nitrogênio no início do período de diferimento.

Abstract This study was conducted from Feb. 25th, 2012 to Jul. 1st, 2012 to recommend nitrogen doses and deferment periods that result in deferred Brachiaria brizantha cv. Piatã (piatã grass) pastures with structural characteristics suitable for animal consumption. Combinations were evaluated between deferment periods and nitrogen fertilization conditions. The deferment periods were long (127 days) and short (79 days). Nitrogen doses were 0, 40, 80, and 120 kg/ha. The experimental design was a randomized block with three replications. The leaf area index (LAI) and light interception (LI) increased with the application of nitrogen. In the absence or at a small nitrogen dose, pasture deferred for short periods presented lower LAI and LI than pasture managed with long deferment period. The nitrogen only influenced the density of vegetative basal tillers. The lower deferment period resulted in a greater number of basal tillers and vegetative air, as well as fewer reproductive basal tillers. Nitrogen increased the length of the leaf blade and the vegetative tiller stem. Long deferral period resulted in longer stem and leaf blade and a larger number of dead leaves. Piatã grass can be deferred for 80 days, with application of 80 kg/ha of nitrogen at the beginning of the deferment period.

RESUMO. Foram avaliados os efeitos de quatro doses de suplemento (0, 1, 2 e 3 kg animal-1 dia-1) sobre as características estruturais do pasto e a produção de bovinos em pastagens com Brachiaria decumbens cv. Basilisk, em lotação contínua com taxa de lotação variável. O delineamento experimental foi de blocos completos casualizados, com duas repetições. O suplemento concentrado não influenciou a massa (4.141 kg ha-1 de MS) e a taxa de produção de forragem (97,6 kg ha dia-1 de MS), os componentes morfológicos e o valor nutritivo na forragem de pastejo simulado. De maneira semelhante, as densidades populacionais de perfilhos vivos (1.607 perfilhos m²) e mortos (636 perfilhos m²) não foram afetadas pelo suplemento concentrado. Ocorreram aumentos lineares no desempenho animal (de 0,70 para 1,13 kg animal-1 dia-1), na taxa de lotação (de 1,9 para 3,8 UA ha-1) e na produção animal por área (de 1,8 a 6,2 kg ha-1 de peso corporal) com as doses de suplemento. O suplemento concentrado não altera as características estruturais de pastos de capim braquiária manejados em lotação contínua e altura de 20 cm, porém incrementa a produção animal.

ABSTRACT. 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 m²) and dead (636 tillers m²) 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.

O trabalho foi realizado para avaliar a dinâmica do perfilhamento durante a rebrotação na primavera (setembro a dezembro de 2009) em pastos de capim-braquiária (Brachiaria decumbens cv. Basilisk) diferidos no início de abril de 2009. Foram avaliadas quatro alturas do pasto no início do diferimento (10, 20, 30 e 40 cm). O delineamento experimental utilizado foi o de blocos completos casualizados com duas repetições. A elevação na altura do pasto no início do diferimento diminuiu a taxa de aparecimento, aumentou a taxa de mortalidade e reduziu a taxa de sobrevivência, o balanço entre aparecimento e mortalidade e o índice de estabilidade da população de perfilhos no início da primavera. Pastos diferidos com altura inicial de 30 e 40 cm apresentaram taxa de aparecimento de perfilhos relativamente estáveis entre o início e final da primavera. Contudo, esses pastos apresentaram maior taxa de mortalidade, menor taxa de sobrevivência, menor balanço entre aparecimento e mortalidade e menor índice de estabilidade da população de perfilhos no início da primavera em relação ao final da primavera. Pastos manejados com menor altura inicial (10 e 20 cm) apresentam maior renovação de tecidos na estação de crescimento subsequente após utilização dos mesmos no inverno.

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.

Objetivou-se identificar a altura do capim-braquiarinha {Urochloa decumbens (Stapf) R. D. Webster cv. Basilisk [syn. Brachiaria decumbens Stapf cv. Basilisk]} no início do diferimento que possibilite adequada estrutura de pasto e seletividade potencial dos bovinos em pastagens diferidas. Foram estudadas quatro alturas do pasto no início do diferimento (10, 20, 30 e 40 cm) e duas amostras de forragem (disponível na pastagem e de pastejo simulado). O delineamento experimental foi em blocos completos casualizado com duas repetições, em esquema de parcela subdividida. Foi registrada maior porcentagem de lâmina foliar viva e menor de colmo vivo e forragem senescente na amostra de forragem em pastejo simulado. O incremento na altura do pasto aumentou o porcentual de forragem senescente e reduziu a porcentagem de lâmina foliar viva nas amostras de forragem. A altura do pasto no início do diferimento não influenciou o índice de seletividade potencial de bovinos para a porcentagem de lâmina foliar viva. O índice de seletividade potencial variou quadraticamente para a porcentagem de colmo vivo e aumentou linearmente para a porcentagem de forragem senescente com a altura do pasto. A redução da altura do pasto para 10 a 20 cm no início do diferimento melhora a estrutura do capim-braquiária diferido e otimiza a seletividade dos bovinos.

Current experiment identified the height of signal grass {Urochloa decumbens (Stapf) R. D. Webster cv. Basilisk [syn. Brachiaria decumbens Stapf cv. Basilisk]} at the beginning of deferment that provided an appropriate pasture structure and potential selectivity by cattle on deferred pastures. Four pasture heights at the beginning of deferment (10, 20, 30 and 40 cm) and two forage samples (available on pasture and simulated grazing) were studied. The experimental design was set in completely randomized blocks, with two replications, in a split-plot arrangement. Higher percentage of live leaf blades and lower percentage of live stems and senescent forage were recorded in the forage sample from simulated grazing. The increase in pasture height increased the percentage of senescent forage and reduced the percentage of live leaf blades in forage samples. Pasture height at the beginning of deferment did not affect the potential selectivity index by cattle for the percentage of live leaf blade. The potential selectivity index varied quadratically for the percentage of live stems and increased linearly for the percentage of senescent forage with pasture height. A 10-to-20 cm reduction in pasture height at the beginning of deferment improved the structure of deferred signal grass and optimized selectivity by cattle.

We assessed the accumulation dynamics of forage and its components in Elephant grass cv. Napier (Pennisetum purpureum Schum.) that were subjected to three post-grazing height treatments (30, 50, and 70 cm) from February through May 2009 (experiment one) and December 2009 through May 2010 (experiment two). In experiment one, the grazing events started when the light interception by the canopy reached 95%. The same was adopted for experiment two, except for the first grazing event, which was based on the height of the apical meristems of basal tillers. The experimental design for both experiments was a randomized complete block with three replications. The pastures that were managed at a post-grazing height of 30 cm exhibited lower rates of leaf and stem growth, total growth and forage accumulation than those that were managed at 50 or 70 cm, indicating that post-grazing height affects Elephant grass. The pastures that were managed at 50 cm exhibited relatively stable accumulation rates and less stem accumulation. Pastures managed at 70 cm of pos-grazing height presented more leaf and stem accumulation. Most apical meristems of Elephant grass should be removed in the first grazing when they reach the post-grazing target height of 50 cm. The elevation in the residual post-grazing height, especially in the summer, raises the regrowth vigor in the Elephant grass cv. Napier pasture. The post-grazing height of 30 cm reduces the growth of the Elephant grass cv. Napier.

This study was carried out to analyze the tillering profile of Guinea grass (Panicum maximum cv. Tanzania) pastures subjected to two grazing frequencies (time necessary to intercept 90 and 95% of the incoming light) and two post-grazing heights (30 and 50 cm) in the period from November 2005 to October 2006. The experimental design was of completely randomized blocks with three replications, in a 2 × 2 factorial arrangement. At the end of the spring, pastures managed with 90% light interception showed greater tiller appearance rates in relation to pastures managed with 95%, regardless of post-grazing height. In the summer and fall, pastures managed with post-grazing height of 30 cm showed higher tiller appearance rates in comparison with pastures managed at 50 cm, regardless of grazing frequency. Concerning the tiller mortality rates, in the summer, higher values were found for pastures managed at 90/50 and 95/30 (interception/height), intermediate values at 90/30 and lower values in those managed at 95/50. Pastures managed at 90/30, 95/30 and 95/50 in the fall presented greater tiller mortality rates than those managed at 90/50. These differences do not occur in the winter/beginning of spring. The stability index remained above 1 all through the experimental period. All management strategies evaluated are adequate for Guinea grass.

Este trabalho foi conduzido para avaliar a densidade populacional de perfilhos e as características estruturais de perfilhos em Brachiaria brizantha cv. Piatã submetida a períodos de diferimento (65, 85 e 105 dias) e alturas iniciais do dossel para o diferimento (20, 30 e 40 cm). Utilizou-se o delineamento experimental de blocos completos casualizados, em esquema de parcelas subdivididas com três repetições. A densidade populacional de perfilhos basais vegetativos e totais foi influenciada pela interação entre períodos e alturas iniciais de diferimento, com menores valores no período de 85 dias associado à altura inicial de 40 cm e no período de 105 dias associado às alturas de 30 e 40 cm. O comprimento de colmo e da lâmina foliar dos perfilhos basais vegetativos aumentou com o aumento nos períodos de diferimento. As alturas iniciais de diferimento tiveram pouco efeito sobre as características estruturais dos perfilhos. O emprego concomitante de plantas altas e longos períodos de diferimento reduz o perfilhamento do capim-piatã. Para otimizar o perfilhamento e a estrutura do pasto diferido na região de Viçosa, MG, o capim-piatã deve ser diferido com altura inicial de 20 a 40 cm, no início de maio e permanecer diferido por 65 dias.

This study was conducted to evaluate the tiller population density and its structural characteristics in Brachiaria brizantha cv. Piata subjected to deferment periods (65, 85 and 105 days) and initial sward heights for deferment (20, 30 and 40 cm). A completely randomized block design was used in a split-plot scheme with three replications. The population density of vegetative basal and total tillers was influenced by the interaction between periods and initial heights of deferment, with lower values in the period of 85 days associated with the initial height of 40 cm and the period of 105 days associated with initial heights of 30 and 40 cm. The length of the stem and leaf blade of vegetative basal tillers increased with the raise in the deferment periods. Initial deferring heights had little effect on the structural characteristics of the tillers. The concomitant use of tall plants and long deferring periods reduces tillering of piata palisade grass. To optimize the tillering and structure of the deferred pasture in the region of Viçosa, piata palisade grass should be deferred with an initial height from 20 to 40 cm in early May and remain deferred for 65 days.

The study was carried out between March 1st and July 1st, 2011, in order to evaluate the tillering pattern of the deferred Piata palisade grass (Brachiaria brizantha cv. Piata). Three sward heights were evaluated in the beginning of the period of deferment: lower (20 cm), medium (30 cm) and higher (40 cm). The experimental design was of completely randomized blocks with three replications. The Piata palisade grass deferred with low initial height presented lower leaf area index, lower light interception and higher leaf angle in relation to the ones deferred with medium and high heights. The advance in the period of deferment increased the leaf area index and the light interception by the sward, in a way that the highest values were recorded in the periods from 91 and 120 days. The leaf angle reduced linearly with the advance in the period of deferment. For basal and aerial tillers, the rates of appearance, mortality and survival of tillers, as well as the balance between appearance and mortality, and the tiller density stability index were not affected by the initial height of the sward. The stability index of the tiller density was lower in the period from 1 to 30 days of deferment in relation to the periods from 31 to 60, from 61 to 90 and from 91 to 120 days. The variation of the initial height of the Piata palisade grass does not influence the tiller density dynamics during the period of deferment. The reduction of the initial height of the Piata palisade grass improves the luminous environment inside the sward, but it does not stimulate the grass tillering during the period of deferment.

This study was conducted to evaluate the daily production of forage and its morphological components, as well as the potential of forage utilization in pastures of Pennisetum purpureum cv. Napier managed with three post-grazing heights (30, 50 and 70 cm). Two experiments were carried out: one from February to May 2009 and another from December 2009 to May 2010, characterizing months of summer and fall. The experimental design was of completely randomized blocks with three replicates. The grazing was performed by crossbred heifers of approximately 270 kg body weight, when the sward intercepted 95% of the incoming light. In both experiments, the pastures managed with post-grazing height of 30 cm, in the summer months (December to March), presented lower daily production of leaves and stems, as well as less daily leaf senescence, which resulted in lower daily forage production and accumulation in comparison with those managed at 70 and 50 cm. In the period from February to March 2009 (experiment 1) and December 2009 to March 2010 (experiment 2), pastures presented greater daily production of leaves and forage, greater daily forage accumulation and more daily leaf senescence in relation to the months of April and May 2009 and 2010. On the other hand, the daily production of stems was higher in the fall, in comparison with the summer. Therefore, elevation in the post-grazing height, especially in the summer, increases the regrowth vigor of elephant grass cv. Napier.

The objective of this study was to determine the deferment period and the most adequate initial sward height of Brachiaria brizantha cv. Piatã for deferment in the region of Viçosa, Minas Gerais. For so, the following characteristics were evaluated: masses and bulk density of forage and its morphological components, light interception by the sward, leaf area index, leaf angle, sward and extended tiller height and falling index of the deferred piatã grass. The three deferment periods assessed (65, 85 and 105 days) were randomized to the plots and the three sward heights (20, 30 and 40 cm), randomized in the subplots. The experimental design was of completely randomized blocks, with three replicates, in a subdivided plots arrangement. Masses of forage, green stem and dead tissue were higher in the piatã grass managed with deferment period of 105 days. The mass of green leaf blade was higher in the piatã grass deferred with 20 cm height associated to the deferment period of 85 days, which had, as consequence, greater bulk density of green leaf blade. The interception of light by the sward was greater in the piatã grass kept longer in deferment associated with the higher leaf area index, regardless of its initial height. The heights of the sward and extended tillers were greater in the piatã grass under periods of 85 and 105 days of deferment; however, the falling index was not affected by the factors studied. In the region of Viçosa, Minas Gerais, B. brizantha cv. Piatã fertilized with 75 kg/ha nitrogen and deferred with initial height of 20 cm and for a period of 85 days, from mid April, has adequate productivity and structure for animal production.

The objective of this research was to assess morphogenetic and structural characteristics of tillers of guinea grass cv. Tanzania at different ages. The pastures of guinea grass were managed in six pasture conditions related to the combination of three frequencies (90, 95, and 99% light interception) and two post-grazing heights (25 and 50 cm). In these six pastures conditions, three tiller ages were evaluated (young, mature, and old). The design was of completely randomized block with three replications. Young tillers exhibited higher leaf appearance rate and leaf elongation rate and, consequently, higher final leaf length and number of live leaves than mature and old tillers, regardless of the pasture condition. On pastures managed with 90 or 95% light interception associated with a post-grazing height of 25 cm, old tillers presented longer leaf lifespan than young and mature ones. There is a progressive reduction in the vigor of growth of pastures of guinea grass cv. Tanzania with advancing tiller age.

This experiment was conducted to estimate the effects of nitrogen fertilization associated with the initial height of the Piata palisade grass on the number and structural characteristics of individual tillers after the deferment period. An area with Brachiaria brizantha cv. Piata measuring approximately 288 m² was used. Combinations of levels of nitrogen fertilization (0, 75 and 150 kg/ha of nitrogen) and initial heights of the sward (low - 20 cm, medium - 30 cm and high - 40 cm) were evaluated. The experimental design was of completely randomized blocks in subdivided plots with three replications. The number of vegetative tillers, the stem length of the vegetative, reproductive and dead tillers, and the number of dead leaves of the reproductive and the dead tillers linearly increased with the elevation in the nitrogen level. The deferred Piata palisade grass with low initial height showed lower number of dead basal tillers, shorter length of stems and leaf blades in reproductive tillers and lower number of live and dead leaves in vegetative tillers in relation to the one managed with height considered medium and high. Nitrogen fertilization, in association with low initial height, provides the optimization of forage of Piata palisade grass in deferment conditions.

Foram avaliadas as características morfogênicas e estruturais de gramíneas forrageiras com o objetivo de agrupá-las, de acordo com seu padrão de desenvolvimento, em seus respectivos grupos funcionais. As gramíneas foram plantadas em parcelas de 1,0 m² com 24 plantas, em delineamento de blocos completos casualizados com três repetições. Os dados foram submetidos à análise de fatores, reduzindo as variáveis em quatro fatores: desenvolvimento de massa, mortalidade de perfilhos, estádio de desenvolvimento e longevidade foliar. Os dados foram submetidos à análise de agrupamento por otimização de Tocher adotando-se a distância euclidiana média como medida básica de dissimilaridade. As gramíneas foram agrupadas da seguinte forma: Verão - grupo I (Xaraés, Massai, Mombaça e Marandu); grupo II (Gordura e Aruana); e grupo III (Jaraguá). Outono - grupo I (Mombaça, Massai, Xaraés, Marandu e Gordura); grupo II - (Jaraguá); e grupo III (Aruana). Possivelmente a maior participação do fator mortalidade de perfilhos na formação dos grupos no período de outono influenciou na reorganização dos grupos. Os padrões de desenvolvimento de massa dos diferentes grupos de gramíneas diferiram entre si quanto à forma de utilização dos recursos disponíveis. Houve mudança nos escores de todos os fatores com a mudança do período do verão para o outono. O agrupamento funcional comprova que gramíneas de gêneros e/ou espécies diferentes podem ser enquadradas em um mesmo grupo.

Morphogenetic and structural characteristics of forage grasses were evaluated in order to group them according to their pattern of development in their respective functional groups. Grasses were planted in plots of 1.0 m² with 24 plants in a completely randomized block design with three replications. Data were submitted to factor analysis, reducing the variables to four factors: mass development, tiller mortality, developmental stage and leaf longevity. The data were submitted to cluster analysis by Tocher's optimization by adopting the mean Euclidean distance as a basic measure of dissimilarity. Grasses were grouped as follows: Summer - the group I (Xaraés, Massai, Mombaca and Marandu); group II (Molassa and Aruana); and group III (Jaraguagrass). Fall - group I (Mombaca, Massai, Xaraés, Marandu and Molassa); group II - (Jaraguagrass); and group III (Aruana). Possibly, the greater role of the tiller mortality factor in the formation of groups in the fall influenced the reorganization of the groups. The patterns of mass development of the different groups of grasses differ from each other as for the means of utilizing the resources available. There was a change in the scores of all factors with the change of the period from summer to Fall. The functional clustering of grasses demonstrates that gender and/or different species can be placed in the same group.