Chemical composition of Andropogon gayanus cv. planaltina predicted through nirs and analyzed through wet chemistry / Composição químico-bromatológica de Andropogon gayanus, cultivar Planaltina, predita pelo NIRS e analisada por via úmida

Objetivou-se comparar os teores dos nutrientes do capim Andropogon gayanus obtidos no equipamento NIRS com os valores obtidos por análises de via úmida, para identificar se os modelos globais de calibração do equipamento NIRS são adequados para predizer a composição químico-bromatológica. As análises de via seca no NIRS foram executadas no Laboratório de Bromatologia e Nutrição Animal (Laban), pertencente à Faculdade de Medicina Veterinária (Famev) da Universidade Federal de Uberlândia (UFU), enquanto as análises de via úmida foram realizadas no Laboratório de Química Analítica de Plantas da Embrapa Cerrados, localizado em Brasília-DF. As amostras utilizadas foram de capim Andropogon gayanus, cultivar Planaltina, as quais, após corte de 20cm acima do solo, foram secas e moídas no tamanho de 1mm. Após a moagem, foram analisadas por via úmida para os teores de matéria seca (MS), matéria mineral (MM), proteína bruta (PB), fibra insolúvel em detergente neutro (FDN) e fibra insolúvel em detergente ácido (FDA), segundo metodologias propostas por Detmann et al. (2012). As amostras moídas foram colocadas em cubetas próprias do equipamento e escaneadas em espectrômetro de refletância no infravermelho próximo (NIRS) NIR, modelo Spectra Star 2600 XT series of Near Infrared Analyzers (Unity Scientific®), em duplicata. Para obtenção dos teores de MS, MM, PB, FDN e FDA, empregaram-se modelos de calibração do próprio equipamento NIRS, utilizando-se a curva de calibração própria do equipamento. As médias dos teores de MS, MM, PB, FDN e FDA obtidas pelas análises de bancada (via úmida) e pelo uso do equipamento NIRS foram comparadas pelo teste T (dados pareados), ao nível de 5% de probabilidade, empregando-se o delineamento em blocos ao acaso. Houve diferença significativa nos nutrientes preditos pelo NIRS e analisados por via úmida (P≤0,05). O NIRS superestimou os teores de matéria seca e matéria mineral, mas subestimou os teores de FDN, FDA e PB. Esse resultado mostra que, quando do uso de modelos globais de calibração, esse equipamento não é capaz de predizer corretamente a composição químico-bromatológica de forrageiras de clima tropical.

Dissimilarity between Andropogon lateralis ecotypes under different defoliation frequencies and heights / Dissimilaridade entre ecótipos de Andropogon lateralis submetidos a diferentes frequências de desfolha e alturas de corte

Andropogon lateralis Nees is a native grass of southern Brazil and is one of the most frequent specie found in native grasslands. The species is widely distributed and has a high degree of phenotypic plasticity, which makes it highly adaptable to different edaphoclimatic conditions and management. This study aimed to evaluate the behavior of twelve ecotypes of A. lateralis, collected in different regions of the state of Rio Grande do Sul and cut to three different heights and subjected to two different defoliation frequencies. From September to February, the ecotypes were evaluated for total dry matter, leaf and stem yields. In addition, total, vegetative and reproductive tillers and plant height were measured. These characteristics are important for the selection of superior genotypes in terms of genetic variability and forage production. Total dry matter and leaf dry matter are characteristics with agronomic importance and they showed the highest correlation (r = 0.77), enabling an indirect selection for one of these characteristics. The natural selection of plants resulted in distinct structural, morphological and productive characteristics with heterogeneity that allows the selection and grouping according to the characteristics, ecotypes with superior agronomic characteristics can be included in breeding programs.

Andropogon lateralis Nees é uma gramínea nativa do sul do Brasil e uma das espécies mais frequentes na flora dos campos nativos da região. Possui ampla distribuição e alto grau de plasticidade fenotípica, tornando-o adaptável as condições edafoclimáticas e a práticas de desfolha. Este estudo teve como objetivo avaliar a dissimilaridade entre doze ecótipos de A. lateralis N., coletados em diferentes regiões do Rio Grande do Sul, submetidos a duas frequências de desfolha e três alturas de corte. No período de setembro a fevereiro, os ecótipos foram avaliados quanto à produção de matéria seca total, de lâminas foliares e de colmo. Além disso, foram medidos o número de perfilhos totais, vegetativos e reprodutivos e a altura das plantas. Essas características são importantes para a seleção de genótipos superiores em termos de variabilidade genética e produção de forragem. A matéria seca total e a matéria seca foliar são características com importância agronômica e apresentaram a maior correlação (r = 0,77), possibilitando uma seleção indireta para uma dessas características. A seleção natural das plantas resultou em características estruturais, morfológicas e produtivas distintas com uma heterogeneidade que permite a seleção e agrupamento de acordo com as características, ecótipos com características agronômicas superiores podem ser incluídos em programas de melhoramento.

Spatial distribution and sample size to estimate Lycosa erythrognatha (Araneae: Lycosidae) population density overwintering / Distribuição espacial e tamanho de amostra para estimar a densidade populacional de Lycosa erythrognatha (Araneae: Lycosidae) durante o inverno

Lycosa erythrognatha Lucas, 1833 (Araneae: Lycosidae) is a predatory arthropod with potential for conservation biological control. In addition to being considered a bioindicator of environmental quality, this arthropod provides an important service for agriculture by reducing insect-pest populations. In this work we seek to understand how the plants Andropogon bicornis L., Saccharum angustifolium Nees and Eustachys retusa Lag (Poales: Poaceae) and their different clump sizes affect the population density, spatial distribution and determination of the minimum number of samples to estimate its population density during the winter. Among the evaluated host plants, S. angustifolium and A. bicornis presented higher population density than E. retusa, but we observed that the clump diameter significantly influences the population density and the minimum number of samples. We observed a gregarious behavior in plants of A. bicornis and E. retusa. For S. angustifolium, a uniform distribution was observed.(AU)

Lycosa erythrognatha Lucas, 1833 (Araneae: Lycosidae) é um artrópode predador com potencial para controle biológico de conservação. Além de ser considerado um bioindicador da qualidade ambiental, esse artrópode fornece um importante serviço para a agricultura, reduzindo as populações de insetos-praga. Neste trabalho buscamos entender como as plantas Andropogon bicornis L., Saccharum angustifolium Nees e Eustachys retusa Lag (Poales: Poaceae) e seus diferentes tamanhos de touceira afetam a densidade populacional, distribuição espacial e a determinação do número mínimo de amostras para estimar sua densidade populacional durante o inverno. Entre as plantas hospedeiras avaliadas, S. angustifolium e A. bicornis apresentaram maior densidade populacional que E. retusa, observamos que o diâmetro da touceira influencia significativamente a densidade populacional e o número mínimo de amostras. Observamos um comportamento gregário nas plantas de A. bicornis e E. retusa. Para S. angustifolium, uma distribuição uniforme foi observada.(AU)

Herbage intake by steers grazing in a natural grassland with predominance of Andropogon lateralis Nees managed under different canopy heights / Consumo de forragem por novilhos em área de pastagem natural com predomínio de Andropogon lateralis Ness manejada em diferentes alturas

The animal performance on pasture is directly correlated to canopy structure since this influences the herbage consumption. This study was evaluated the effects of four pre-grazing canopy heights (12, 20, 28 and 36 cm) of Andropogon lateralis Ness on herbage intake and feeding behavior of steers in a natural grassland under intermittent stocking management, using the same proportion of defoliation (40% reduction in pre-grazing height, i.e., post-grazing heights of 7.2, 12.0, 16.8 and 21.6 cm). The experiment was conducted on a total area of ​​14,000 m2, divided into sixteen paddocks of 875 m2. Thirty-two steers were used, divided into uniform pairs according to the live weight (LW) at the start of the experiment (244 ± 23.0 kg). Each paddock was subdivided into three plots of identical area; the first two plots were used for the adaptation period and the third for the assessment period. A randomized block design was used with four replicates and two assessment periods. Herbage mass and neutral detergent fiber content increased linearly (P < 0,001) with the increase of pre-grazing canopy heights. In contrast, was not affected by treatments, with mean values ​​of 75 g/kg of dry matter (DM) in the upper stratum and 83 g/kg of DM in lower stratum. The herbage intake was similar between treatments (P = 0.255), averaging 1.78% LW. Grazing time increased linearly in the upper stratum and decreased linearly in the lower stratum with increasing pre-grazing canopy heights. Total time spent grazing, ruminating, and idling did not differ between treatments, with means of 52.6%, 23.0%, and 24.2%, respectively. Pre-grazing canopy heights treatments, based on the predominant species A. lateralis, did not affect the daily herbage intake of steers.

O desempenho de animais em pastejo possui direta correlação com a estrutura do dossel forrageiro, uma vez que este influencia o consumo. Objetivou-se mensurar o consumo e o comportamento ingestivo de novilhos em pastagem natural “palha grossa”, manejada sob lotação intermitente, com diferentes alturas de pré pastejo (12, 20, 28, 36 cm), aferidas na espécie predominante Andropogon lateralis Ness, com severidade de desfolha de 40%. O experimento foi conduzido em uma área total de 14.000 m2, dividida em dezesseis piquetes de 875 m2. Foram utilizados 32 novilhos, divididos em lotes uniformes conforme o peso vivo no início do experimento (244 ± 23,0 kg). Cada piquete foi subdividido em três parcelas de igual área, sendo utilizadas as duas primeiras para o período de adaptação e a terceira para o período de avaliação. O delineamento experimental foi de blocos ao acaso, com quatro repetições e dois períodos de avaliação. As metas de altura em pré-pastejo foram alcançadas em todos os tratamentos. A massa de forragem aumentou linearmente (P < 0,001) com o aumento das alturas de pré-pastejo. Os teores de fibra em detergente neutro aumentaram linearmente (P < 0,001) com o aumento das alturas de manejo, enquanto a proteína bruta foi semelhante (P=0,107) entre os tratamentos tendo valores médios de 75 g/kg de matéria seca (MS) no estrato superior e de 83 g/kg MS no estrato inferior. O consumo de forragem foi similar entre tratamentos (P=0,255), com média de 1,78% do peso vivo. A porcentagem de tempo que os animais pastejaram no estrato superior aumentou e a porcentagem no estrato inferior diminuiu linearmente (P < 0,001) com o aumento das alturas de manejo. As porcentagens do tempo total destinado ao pastejo, ruminação ou ócio não diferiram entre [...].

Production and quality of tropical grasses at different regrowth intervals in the Brazilian semiarid

The objective of this study was to evaluate the production and chemical composition of three forage species at different regrowth intervals. A 3 x 4 randomized-block factorial design with three forage species (Andropogon, Buffel, and Massai) and four regrowth intervals (21, 35, 49, and 63 days) was used. There was no interaction (p > 0.05) between forage species and regrowth interval on any of the chemical components evaluated. The crude protein content decreased but the contents of neutral detergent fiber, acid detergent fiber and hemicellulose increased with increasing regrowth interval (p > 0.05). Only the contents of crude protein and ether extract were similar (p > 0.05) among grasses. A significant interaction was observed (p < 0.05) between forage species and regrowth interval on forage mass. Andropogon grass had the highest forage mass at 63 days (3,270.1 kg ha-1 DM cut-1) and the highest productivity regardless of the regrowth interval (19.1 t ha-1 DM year-1). Therefore, Andropogon grass was the most productive forage among the tested species. Pastures should be managed with shorter growth intervals due to the highest crude protein level and the lowest contents of neutral detergent fiber and acid detergent fiber.

Herbage intake by steers grazing in a natural grassland with predominance of Andropogon lateralis Nees managed under different canopy heights / Consumo de forragem por novilhos em área de pastagem natural com predomínio de Andropogon lateralis Ness manejada em diferentes alturas

The animal performance on pasture is directly correlated to canopy structure since this influences the herbage consumption. This study was evaluated the effects of four pre-grazing canopy heights (12, 20, 28 and 36 cm) of Andropogon lateralis Ness on herbage intake and feeding behavior of steers in a natural grassland under intermittent stocking management, using the same proportion of defoliation (40% reduction in pre-grazing height, i.e., post-grazing heights of 7.2, 12.0, 16.8 and 21.6 cm). The experiment was conducted on a total area of ​​14,000 m2, divided into sixteen paddocks of 875 m2. Thirty-two steers were used, divided into uniform pairs according to the live weight (LW) at the start of the experiment (244 ± 23.0 kg). Each paddock was subdivided into three plots of identical area; the first two plots were used for the adaptation period and the third for the assessment period. A randomized block design was used with four replicates and two assessment periods. Herbage mass and neutral detergent fiber content increased linearly (P < 0,001) with the increase of pre-grazing canopy heights. In contrast, was not affected by treatments, with mean values ​​of 75 g/kg of dry matter (DM) in the upper stratum and 83 g/kg of DM in lower stratum. The herbage intake was similar between treatments (P = 0.255), averaging 1.78% LW. Grazing time increased linearly in the upper stratum and decreased linearly in the lower stratum with increasing pre-grazing canopy heights. Total time spent grazing, ruminating, and idling did not differ between treatments, with means of 52.6%, 23.0%, and 24.2%, respectively. Pre-grazing canopy heights treatments, based on the predominant species A. lateralis, did not affect the daily herbage intake of steers.(AU)

O desempenho de animais em pastejo possui direta correlação com a estrutura do dossel forrageiro, uma vez que este influencia o consumo. Objetivou-se mensurar o consumo e o comportamento ingestivo de novilhos em pastagem natural “palha grossa”, manejada sob lotação intermitente, com diferentes alturas de pré pastejo (12, 20, 28, 36 cm), aferidas na espécie predominante Andropogon lateralis Ness, com severidade de desfolha de 40%. O experimento foi conduzido em uma área total de 14.000 m2, dividida em dezesseis piquetes de 875 m2. Foram utilizados 32 novilhos, divididos em lotes uniformes conforme o peso vivo no início do experimento (244 ± 23,0 kg). Cada piquete foi subdividido em três parcelas de igual área, sendo utilizadas as duas primeiras para o período de adaptação e a terceira para o período de avaliação. O delineamento experimental foi de blocos ao acaso, com quatro repetições e dois períodos de avaliação. As metas de altura em pré-pastejo foram alcançadas em todos os tratamentos. A massa de forragem aumentou linearmente (P < 0,001) com o aumento das alturas de pré-pastejo. Os teores de fibra em detergente neutro aumentaram linearmente (P < 0,001) com o aumento das alturas de manejo, enquanto a proteína bruta foi semelhante (P=0,107) entre os tratamentos tendo valores médios de 75 g/kg de matéria seca (MS) no estrato superior e de 83 g/kg MS no estrato inferior. O consumo de forragem foi similar entre tratamentos (P=0,255), com média de 1,78% do peso vivo. A porcentagem de tempo que os animais pastejaram no estrato superior aumentou e a porcentagem no estrato inferior diminuiu linearmente (P < 0,001) com o aumento das alturas de manejo. As porcentagens do tempo total destinado ao pastejo, ruminação ou ócio não diferiram entre [...].(AU)

Production and quality of tropical grasses at different regrowth intervals in the Brazilian semiarid

The objective of this study was to evaluate the production and chemical composition of three forage species at different regrowth intervals. A 3 x 4 randomized-block factorial design with three forage species (Andropogon, Buffel, and Massai) and four regrowth intervals (21, 35, 49, and 63 days) was used. There was no interaction (p > 0.05) between forage species and regrowth interval on any of the chemical components evaluated. The crude protein content decreased but the contents of neutral detergent fiber, acid detergent fiber and hemicellulose increased with increasing regrowth interval (p > 0.05). Only the contents of crude protein and ether extract were similar (p > 0.05) among grasses. A significant interaction was observed (p < 0.05) between forage species and regrowth interval on forage mass. Andropogon grass had the highest forage mass at 63 days (3,270.1 kg ha-1 DM cut-1) and the highest productivity regardless of the regrowth interval (19.1 t ha-1 DM year-1). Therefore, Andropogon grass was the most productive forage among the tested species. Pastures should be managed with shorter growth intervals due to the highest crude protein level and the lowest contents of neutral detergent fiber and acid detergent fiber.(AU)

Goat performance on pure Andropogon gayanus pastures or associated with legumes.

The objective of this study was to evaluate the grazing of goats in a grass monoculture system and in intercropping systems of grass + legumes. A randomized block design was adopted, with the treatments arranged in a split-plots scheme. The plots consisted of three cropping systems: monoculture-Andropogon gayanus cv. Planaltina; mixture I-A. gayanus cv. Planaltina + Stylosanthes cv. Campo Grande; and mixture II-A. gayanus cv. Planaltina + Calopogonium mucunoides. The subplots consisted of two grazing cycles. The highest (P = 0.04) total forage mass (TFM) was recorded in the mixture I (A. gayanus cv. Planaltina + Stylosanthes. cv. Campo Grande), which was 2.6 ± 0.1 tons DM/ha. The crude protein (CP) was lower in the monoculture which also showed the highest content of neutral detergent fiber (NDF). The grazing time in the monoculture was the longest (8.23 ± 1.14 h). The goats used a longer time for rumination (P < 0.01) in the mixture I. The lowest (P < 0.01) bite rate was found in mixture II in comparison to the other cropping systems. The bite rate was higher (P < 0.01) in grazing cycle II than in all the other cropping systems. In mixture I, the Stylosanthes cv. Campo Grande, and in mixture II, the C. mucunoides presented the lowest (P < 0.01) δ13C value in the forage. The highest forage intake occurred in the mixture systems (P < 0.01) in comparison to the monoculture. The mixture pastures presented better results for forage mass, nutritive value, and intake in comparison to the monoculture.

Morphogenetic and structural characteristics of gamba grass subjected to nitrogen fertilization and different defoliation intensities / Características morfogênicas e estruturais do capim-andropógon submetido à adubações nitrogenadas e intensidades de desfolha

This study aimed to evaluate the morphogenetic, structural, and productive characteristics of Andropogon gayanus cv. 'Planaltina' subjected to different nitrogen fertilization levels and defoliation intensities. The experiment was done in a completely randomized design with a factorial arrangement of six nitrogen doses (0, 100, 200, 300, 400, and 500 kg N ha-1) and two defoliation intensities (15 and 30 cm). The production and structure data were grouped into rainy and dry periods, while morphogenesis data were compared only among different fertilization and defoliation intensities. The total dry forage biomass (TDFB), dry mass of leaves (DML), dry mass of stems (DMS), and dead forage dry mass (DFDM) were then determined. In addition to these variables, the morphogenetic characteristics of the plants and the numbers of tillers alive and dead were evaluated. There was no interaction (P>0.05) between the effects of nitrogen fertilization doses and the intensity of defoliation on TDFB, DML, DMS, and DFDM in both of the evaluated phases (rainy and dry). It was also observed that the rates of leaf elongation, leaf appearance, and leaf blade elongation increased with nitrogen fertilization. On the other hand, the culm elongation rate and phyllochron decreased as the dose applied increased. The defoliation intensity did not influence (P>0.05) the morphogenetic characteristics examined, nor did it affect the senescence rate of nitrogen in leaves and number of live leaves per tiller. The number of dead tillers increased linearly during the rainy period. Based on these results, to improve the efficiency of production of gamba grass it is recommended that it be managed with a defoliation intensity of 30 cm and nitrogen fertilization of 286.52 kg N ha-1 year-1.

Objetivou-se avaliar as características morfogênicas, produtivas e estruturais do Andropogon gayanus cv. Planaltina submetido a níveis de adubação nitrogenada e intensidades de desfolha. O delineamento experimental foi o inteiramente casualizado com arranjo fatorial 6x2, doses de nitrogênio (0, 100, 200, 300, 400 e 500 kg de nitrogênio ha-1) e intensidades de desfolhas (15 e 30 cm). Os dados de produção e estrutura foram agrupados em períodos chuvoso e seco e os de morfogênese analisados somente em função da adubação e intensidade de desfolha. Foi determinada a produção de biomassa de forragem seca total (BFST), massa seca de folhas (MSF), massa seca de colmos (MSC) e massa seca de forragem morta (MSFM). Além dessas variáveis foram avaliadas as características morfogênicas e de perfilhos vivos e mortos. Houve interação (P<0,05) entre as doses e intensidade de desfolhas para a MSFT, MSF, MSC e MSFM em ambas as fases de avaliação. Observou-se que as taxas de alongamento foliar, aparecimento foliar e comprimento da lâmina foliar aumentaram com a adubação nitrogenada. Por outro lado, a taxa de alongamento do colmo e Filocrono diminuíram com a aplicação das doses crescentes. As intensidades de desfolha não influenciaram (P>0,05) nas características morfogênicas, assim como a adubação na taxa de senescência foliar e número de folhas vivas por perfilho. O número de perfilhos mortos aumentou de forma linear durante o período chuvoso. Recomenda-se manejar o capim-andropógon com intensidade de desfolha de 30 cm e adubação nitrogenada de 286,52 kg de N ha-1 ano-1, visando a maior produção.

Interactions of cadmium and zinc in high zinc tolerant native species Andropogon gayanus cultivated in hydroponics: growth endpoints, metal bioaccumulation, and ultrastructural analysis.

Cadmium (Cd) and zinc (Zn) toxicity causes physiological disorders and harms plants, interfering with the rehabilitation of areas affected by mining activities. This study evaluated how the exposure to Zn and/or Cd affects the growth of native andropogon grass (Andropogon gayanus Kunth) plants originally found in areas contaminated with Cd and/or Zn due to zinc mining activities. Plants were cultivated for 7 weeks in a nutrient solution treated with Zn (142.3-854.0 µM) or Cd (0.9-13.3 µM) separately or combined with a molar ratio of 64:1 (Zn:Cd). A control treatment was grown in a complete Hoagland and Arnon solution (without Cd). Plant height, stem diameter, internode length, dry weight, Cd and Zn concentration, and accumulation in shoots/roots, as well as ultrastructure of roots and leaves were analyzed at the end of the experiment. The root dry weight was not significantly affected by the addition of the metals. Moreover, Zn provided higher shoot dry weight (up to 160%) relative to control. Andropogon grass tolerated both metals better separately than when applied together. Transmission electron microscopy analyses showed modifications such as vesiculation and vacuolation in the ultrastructure of andropogon tissues by Cd and/or Zn. The andropogon grass was tolerant to the doses tested, evidencing that it has potential for recovering areas contaminated with Zn and/or Cd.

Population density and tillering of andropogon grass submitted to different cutting heights / Densidade populacional e perfilhamento de capim-andropógon submetido a diferentes alturas de corte

The objective of this study was to evaluate the tillering dynamics and population density of Andropogon gayanus cv. Planaltina, submitted to different cutting heights during the dry and rainy season. A randomized block design was adopted in a split plot scheme. In the main plot, the three cutting heights (10, 20, and 30 cm) were allocated, while the subplots included the following periods: dry (October, November, and December) and rainy (April, May, and June). During the dry period at the height of 10 cm, there was a higher population density of tillers, with 1298.44 tillers m-2. The appearance rate was higher in October for heights of 10 and 30 cm and in December for 20 cm. The 10-cm height provided a higher mortality rate. The survival rate and the stability index were higher in October, with 88.47% and 1.38, respectively. In the rainy season, specifically June, the pasture had a higher height (130.06 cm). The rate of appearance and the stability index were higher in April and during June there was greater mortality, while at the 20-cm height, there was less mortality and greater survival (85.71%) of the tillers. The 20-cm cut height provides a higher survival rate and lower mortality rate of andropogon grass in the dry and rainy season.(AU)

Objetivou-se avaliar a dinâmica de perfilhamento e densidade populacional de perfilhos de capim Andropogon gayanus cv. Planaltina, submetido a diferentes alturas de corte durante o período seco e chuvoso. Adotou-se o delineamento em blocos ao acaso em esquema de parcelas subdivididas. Na parcela principal alocaram-se as três alturas de corte (10, 20 e 30 cm) e nas subparcelas, os períodos: seco (outubro, novembro e dezembro) e chuvoso (abril, maio e junho). No período seco, na altura de 10 cm houve maior densidade populacional de perfilhos, com 1298,44 perfilhos/m2. A taxa de aparecimento foi maior em outubro para as alturas de 10 e 30 cm e no mês de dezembro na altura de 20 cm. A altura de 10 cm proporcionou maior taxa de mortalidade. A taxa sobrevivência e o índice de estabilidade foram superiores no mês de outubro, com 88,47% e 1,38, respectivamente. No período chuvoso, no mês de junho, o pasto obteve maior altura (130,06 cm). A taxa de aparecimento e o índice de estabilidade foram superiores no mês de abril e durante o mês de junho ocorreu maior mortalidade, enquanto que na altura de 20 cm, houve menor mortalidade e maior sobrevivência (85,71%) dos perfilhos. A altura de 20 cm de corte proporciona maior equilíbrio no desenvolvimento dos perfilhos.(AU)

Population density and tillering of andropogon grass submitted to different cutting heights / Densidade populacional e perfilhamento de capim-andropógon submetido a diferentes alturas de corte

The objective of this study was to evaluate the tillering dynamics and population density of Andropogon gayanus cv. Planaltina, submitted to different cutting heights during the dry and rainy season. A randomized block design was adopted in a split plot scheme. In the main plot, the three cutting heights (10, 20, and 30 cm) were allocated, while the subplots included the following periods: dry (October, November, and December) and rainy (April, May, and June). During the dry period at the height of 10 cm, there was a higher population density of tillers, with 1298.44 tillers m-2. The appearance rate was higher in October for heights of 10 and 30 cm and in December for 20 cm. The 10-cm height provided a higher mortality rate. The survival rate and the stability index were higher in October, with 88.47% and 1.38, respectively. In the rainy season, specifically June, the pasture had a higher height (130.06 cm). The rate of appearance and the stability index were higher in April and during June there was greater mortality, while at the 20-cm height, there was less mortality and greater survival (85.71%) of the tillers. The 20-cm cut height provides a higher survival rate and lower mortality rate of andropogon grass in the dry and rainy season.

Objetivou-se avaliar a dinâmica de perfilhamento e densidade populacional de perfilhos de capim Andropogon gayanus cv. Planaltina, submetido a diferentes alturas de corte durante o período seco e chuvoso. Adotou-se o delineamento em blocos ao acaso em esquema de parcelas subdivididas. Na parcela principal alocaram-se as três alturas de corte (10, 20 e 30 cm) e nas subparcelas, os períodos: seco (outubro, novembro e dezembro) e chuvoso (abril, maio e junho). No período seco, na altura de 10 cm houve maior densidade populacional de perfilhos, com 1298,44 perfilhos/m2. A taxa de aparecimento foi maior em outubro para as alturas de 10 e 30 cm e no mês de dezembro na altura de 20 cm. A altura de 10 cm proporcionou maior taxa de mortalidade. A taxa sobrevivência e o índice de estabilidade foram superiores no mês de outubro, com 88,47% e 1,38, respectivamente. No período chuvoso, no mês de junho, o pasto obteve maior altura (130,06 cm). A taxa de aparecimento e o índice de estabilidade foram superiores no mês de abril e durante o mês de junho ocorreu maior mortalidade, enquanto que na altura de 20 cm, houve menor mortalidade e maior sobrevivência (85,71%) dos perfilhos. A altura de 20 cm de corte proporciona maior equilíbrio no desenvolvimento dos perfilhos.

Post-treatment of paint industry effluents by filtration using Andropogon biochar (Andropogon gayanus Kunth cv. Planaltina).

This study evaluates the filtration potential of the biomass obtained from Andropogon grass (Andropogon gayanus Kunth cv. Planaltina) that was converted to biochar by pyrolysis. The biochar is used in filtration systems for the post-treatment of paint industry effluents. The biomass is characterized by elemental analysis (CHSN-O), determination of specific compounds (cellulose/hemicellulose/lignin), FTIR, and SEM. The produced biochar is characterized by SEM, TGA, and surface area analysis. The efficiency of the filters is evaluated by the following parameters: color, turbidity, removal of total solids (suspended and sedimentable), chemical oxygen demand (COD), and metals (Al, Cu, Zn, Co, Cd, and Cr(VI)). Over 99% removal of aluminum, cadmium, and hexavalent chromium is achieved. Moreover, almost 100% of COD and solids are removed, whereas turbidity and color are reduced by over 90%.

Morphogenic and structural characteristics of tropical forage grasses managed under different regrowth periods in the Brazilian semi-arid region / Características morfogênicas e estruturais de gramíneas forrageiras tropicais manejadas com diferentes períodos de rebrotação no semiárido brasileiro

The objective of this study was to evaluate the morphogenetic and structural characteristics of tropical grasses managed under different regrowth periods. The experiment was conducted at the Federal Institute of Science and Technology Education of Rio Grande do Norte, located in the municipality of Apodi-RN, Brazil. The study design was in randomized blocks and the treatments were allocated in a 3x4 factorial arrangement, with three cultivars (Andropogon, Buffel and Massai) in four regrowth periods (21, 35, 49 and 63 days). The interaction between cultivar and age was significant for all studied variables, with the exception of leaf blade width and accumulation rate. The highest leaf appearance rates were observed in Buffel grass, regardless of the regrowth age. This characteristic was not influenced by age only in Andropogon grass. Higher stem elongation rates were observed in Buffel grass, while the lowest were observed in Massai grass until 35 days of regrowth, attributed to the presence of inflorescences. Canopy heights in Massai and Andropogon grass were greater than Buffel grass until 35 days of regrowth, Andropogon grass had higher height from 35 days of regrowth than the others. Andropogon grass showed higher rates of accumulation than Massai grass only at 21 days of regrowth, and no effects of regrowth age were observed for this variable. Buffel grass should be defoliated at 21 days, while Andropogon and Massai grass can be managed without losses between 21 and 63 days of regrowth.(AU)

Objetivou-se avaliar as características morfogênicas e estruturais de gramíneas tropicais manejadas sob diferentes períodos de rebrotação. O experimento foi conduzido no Instituto Federal de Educação Ciência e Tecnologia do Rio Grande do Norte, localizado no município de Apodi-RN. O delineamento foi em blocos ao acaso e os tratamentos foram alocados em arranjo fatorial 3x4, sendo três cultivares (Andropogon, Buffel e Massai) em quatro períodos de rebrotação (21, 35, 49 e 63 dias). A interação entre cultivar e idade foi significativa para todas as variáveis estudadas, com exceção da largura da lâmina foliar e da taxa de acúmulo. As maiores taxas de aparecimento de folhas foram observadas no capim-buffel, independentemente da idade de rebrotação. Apenas no capim-andropogon, essa característica não foi influenciada pela idade. As maiores taxas de alongamento de colmo foram observadas no capim-buffel e as menores no capim-massai até os 35 dias de rebrotação, atribuído a presença de inflorescências. As alturas do dossel dos capim-massai e capim-andropogon foram maiores que a do capim-buffel até os 35 dias rebrotação, a partir dos 35 dias de rebrotação o capim-andropogon apresentou maior altura que os demais. O capim-andropogon obteve maior taxa de acúmulo que o capim-massai apenas aos 21 dias de rebrotação. O capim-buffel deve ser desfolhado aos 21 dias, enquanto que os capins andropogon e massai podem ser manejados sem prejuízos entre 21 e 63 dias de rebrotação.(AU)

Morphogenic and structural characteristics of tropical forage grasses managed under different regrowth periods in the Brazilian semi-arid region / Características morfogênicas e estruturais de gramíneas forrageiras tropicais manejadas com diferentes períodos de rebrotação no semiárido brasileiro

The objective of this study was to evaluate the morphogenetic and structural characteristics of tropical grasses managed under different regrowth periods. The experiment was conducted at the Federal Institute of Science and Technology Education of Rio Grande do Norte, located in the municipality of Apodi-RN, Brazil. The study design was in randomized blocks and the treatments were allocated in a 3x4 factorial arrangement, with three cultivars (Andropogon, Buffel and Massai) in four regrowth periods (21, 35, 49 and 63 days). The interaction between cultivar and age was significant for all studied variables, with the exception of leaf blade width and accumulation rate. The highest leaf appearance rates were observed in Buffel grass, regardless of the regrowth age. This characteristic was not influenced by age only in Andropogon grass. Higher stem elongation rates were observed in Buffel grass, while the lowest were observed in Massai grass until 35 days of regrowth, attributed to the presence of inflorescences. Canopy heights in Massai and Andropogon grass were greater than Buffel grass until 35 days of regrowth, Andropogon grass had higher height from 35 days of regrowth than the others. Andropogon grass showed higher rates of accumulation than Massai grass only at 21 days of regrowth, and no effects of regrowth age were observed for this variable. Buffel grass should be defoliated at 21 days, while Andropogon and Massai grass can be managed without losses between 21 and 63 days of regrowth.

Objetivou-se avaliar as características morfogênicas e estruturais de gramíneas tropicais manejadas sob diferentes períodos de rebrotação. O experimento foi conduzido no Instituto Federal de Educação Ciência e Tecnologia do Rio Grande do Norte, localizado no município de Apodi-RN. O delineamento foi em blocos ao acaso e os tratamentos foram alocados em arranjo fatorial 3x4, sendo três cultivares (Andropogon, Buffel e Massai) em quatro períodos de rebrotação (21, 35, 49 e 63 dias). A interação entre cultivar e idade foi significativa para todas as variáveis estudadas, com exceção da largura da lâmina foliar e da taxa de acúmulo. As maiores taxas de aparecimento de folhas foram observadas no capim-buffel, independentemente da idade de rebrotação. Apenas no capim-andropogon, essa característica não foi influenciada pela idade. As maiores taxas de alongamento de colmo foram observadas no capim-buffel e as menores no capim-massai até os 35 dias de rebrotação, atribuído a presença de inflorescências. As alturas do dossel dos capim-massai e capim-andropogon foram maiores que a do capim-buffel até os 35 dias rebrotação, a partir dos 35 dias de rebrotação o capim-andropogon apresentou maior altura que os demais. O capim-andropogon obteve maior taxa de acúmulo que o capim-massai apenas aos 21 dias de rebrotação. O capim-buffel deve ser desfolhado aos 21 dias, enquanto que os capins andropogon e massai podem ser manejados sem prejuízos entre 21 e 63 dias de rebrotação.

Amending potential of organic and industrial by-products applied to heavy metal-rich mining soils.

Mining activities promote the development of economies and societies, yet they cause environmental impacts that must be minimized so that their benefits overcome the likely risks. This study evaluated eco-friendly technologies based on the use of low-carbon footprint wastes and industrial by-products as soil amendments for the revegetation of Zn-mining areas. Our goal was to select adequate soil amendments that can be used to recover these areas, with a focus on low-cost materials. The amendments - limestone, sewage sludge, biochar, and composted food remains - were first characterized concerning their chemical composition and structural morphologies. Soil samples (Entisol, Oxisol, Technosol) from three different areas located inside an open-pit mine were later incubated for 60 days with increasing doses of each soil amendment, followed by cultivation with Andropogon gayanus, a native species. The amendments were able to change not only soil pH, but also the phytoavailable levels of Cd, Zn, and Pb. Limestone and biochar were the amendments that caused the highest pH values, reducing the phytoavailability of the metals. All amendments improved seed germination; however, the composted food remains presented low levels of germination, which could make the amendments unfeasible for revegetation efforts. Our findings showed that biochar, which is a by-product of the mining company, is the most suitable amendment to enhance revegetation efforts in the Zn-mining areas, not only because of its efficiency and cost, but also due to its low carbon footprint, which is currently the trend for any "green remediation" proposal.

Fractionation of nitrogen compounds and carbohydrates in forages of different ages / Fracionamento de compostos nitrogenados e carboidratos em forragens de diferentes idades

Here we tested how feeding with exogenous enzymes affects the performance, carcass yield, and ilealdigestibility in broilers from 21- to 42-days-old. The study included 1008 male broilers randomlydistributed into six diets: positive control (PC), corn and soybean meal containing all the nutritionalrequirements; negative control (NC), with a 120 kcal.kg-1 reduction in metabolizable energy relative tothe PC; enzyme complex one (NC + 100 ppm of endo-1,4-beta-xylanase); enzyme complex two (NC+ 200 ppm of xylanase, amylase and protease); enzyme blend one (NC + 100 FXU kg-1 of xylanaseand 200 FXU kg-1 of amylase); and enzyme blend two (NC + 100 FXU kg-1 of xylanase and 300 FXUkg-1 of amylase). The enzyme complex two (CN + 100 FXU.kg de xilanase e 300 FXU.kg de amilase)and enzyme blend two (NC + 100 FXU kg-1 of xylanase and 300 FXU kg-1 of amylase) had greaterweight gain, feed conversion, carcass yield, and digestibility of nutrients than the NC (P < 0,05). Wefound that enzyme complex two and enzyme blend two valued their nutritional matrix promoting betterperformance and digestibility of broilers.(AU)

O trabalho foi realizado para avaliar o uso de enzimas sobre o desempenho, rendimento de carcaça edigestibilidade ileal em frangos de corte no período de 21 a 42 dias de idade. Foram utilizados 1008frangos de corte, machos, distribuídos em seis dietas: controle positivo (CP) a base de milho e farelo desoja, contendo todas as exigências nutricionais, controle negativo (CN) com redução de 120 kcal.kg-1deenergia metabolizável, complexo enzimático um (CN + 100 ppm de endo-1,4-beta-xilanase); complexoenzimático dois ( CN + 200 ppm de xilanase, amilase e protease); blend enzimático um (CN + 100 FXU.kg de xilanase e 200 FXU.kg de amilase e blend enzimático dois (CN + 100 FXU.kg de xilanase e 300FXU.kg de amilase). O complexo enzimático dois (CN + 200 ppm de xilanase, amilase e protease) eblend enzimático dois (CN + 100 FXU.kg de xilanase e 300 FXU.kg de amilase) proporcionaram ganhode peso, conversão alimentar, rendimento de carcaça e digestibilidade de nutrientes superior ao controlenegativo (P < 0,05). Concluiu-se que o complexo enzimático dois e blend enzimático dois valorizaramsua matriz nutricional promovendo melhor desempenho e digestibilidade em frangos de corte.(AU)

Fractionation of nitrogen compounds and carbohydrates in forages of different ages / Fracionamento de compostos nitrogenados e carboidratos em forragens de diferentes idades

Here we tested how feeding with exogenous enzymes affects the performance, carcass yield, and ilealdigestibility in broilers from 21- to 42-days-old. The study included 1008 male broilers randomlydistributed into six diets: positive control (PC), corn and soybean meal containing all the nutritionalrequirements; negative control (NC), with a 120 kcal.kg-1 reduction in metabolizable energy relative tothe PC; enzyme complex one (NC + 100 ppm of endo-1,4-beta-xylanase); enzyme complex two (NC+ 200 ppm of xylanase, amylase and protease); enzyme blend one (NC + 100 FXU kg-1 of xylanaseand 200 FXU kg-1 of amylase); and enzyme blend two (NC + 100 FXU kg-1 of xylanase and 300 FXUkg-1 of amylase). The enzyme complex two (CN + 100 FXU.kg de xilanase e 300 FXU.kg de amilase)and enzyme blend two (NC + 100 FXU kg-1 of xylanase and 300 FXU kg-1 of amylase) had greaterweight gain, feed conversion, carcass yield, and digestibility of nutrients than the NC (P < 0,05). Wefound that enzyme complex two and enzyme blend two valued their nutritional matrix promoting betterperformance and digestibility of broilers.

O trabalho foi realizado para avaliar o uso de enzimas sobre o desempenho, rendimento de carcaça edigestibilidade ileal em frangos de corte no período de 21 a 42 dias de idade. Foram utilizados 1008frangos de corte, machos, distribuídos em seis dietas: controle positivo (CP) a base de milho e farelo desoja, contendo todas as exigências nutricionais, controle negativo (CN) com redução de 120 kcal.kg-1deenergia metabolizável, complexo enzimático um (CN + 100 ppm de endo-1,4-beta-xilanase); complexoenzimático dois ( CN + 200 ppm de xilanase, amilase e protease); blend enzimático um (CN + 100 FXU.kg de xilanase e 200 FXU.kg de amilase e blend enzimático dois (CN + 100 FXU.kg de xilanase e 300FXU.kg de amilase). O complexo enzimático dois (CN + 200 ppm de xilanase, amilase e protease) eblend enzimático dois (CN + 100 FXU.kg de xilanase e 300 FXU.kg de amilase) proporcionaram ganhode peso, conversão alimentar, rendimento de carcaça e digestibilidade de nutrientes superior ao controlenegativo (P < 0,05). Concluiu-se que o complexo enzimático dois e blend enzimático dois valorizaramsua matriz nutricional promovendo melhor desempenho e digestibilidade em frangos de corte.

Ruminal kinetics of tropical forrages submitted or not to irrigation / Cinética ruminal de forrageiras tropicais submetidas ou não a sistema de irrigação

This study evaluated the chemical composition and kinetics of ruminal fermentation of four forage species submitted or not to irrigation. The species evaluated were Urochloa brizantha cv. MG5 (MG-5), Andropogon gayanus (Andropogon), Urochloa humidicola (Humidicola), and Digitaria umfolozi. The experiment was conducted on the Campus Rural experimental farm, São Cristóvão, SE. Significant differences (P<0.0001) were observed in the content of dry matter (DM), organic matter (OM), crude protein (CP), nonfibrous carbohydrates (NFC), hemicellulose, acid detergent fiber (ADF), cellulose, and lignin. Andropogon exhibited higher DM, OM, CP, ADF and lignin concentrations. NFC and cellulose content was higher in MG-5 grass. A significant difference (P=0.0002 and P=0.0004) was observed in the rate of DM and OM disappearance, respectively. These rates were higher in D. umfolozi and Humidicola, as well as in irrigated versus non-irrigated forages. There was a significant difference in cumulative gas volume which was higher in Andropogon and MG-5 compared to the other forages. Significant differences were also found in the fermentation parameters, with Andropogon grass exhibiting a lower volume and rate of gas production from the fractions of fast and slow digestion, as well as a higher lag time. Irrigation does not affect the fermentation parameters of forages and reduces their DM and CP content. The higher protein and lignin content and lower NFC content observed in Andropogon reduced fermentation parameters and cumulative gas production over time. Humidicola exhibits a higher volume of gas produced, as well as a higher gas volume from the faster- and slower-digesting fractions and the highest gas production from these fractions.

Avaliou-se a composição química e a cinética de fermentação ruminal de quatro es-pécies forrageiras submetidas ou não à irrigação. As espécies avaliadas foram Urochloa brizantha cv. MG5 (MG-5), Andropogon gayanus (Andropogon), Urochloa humidicola (Humidicola) e Digitaria umfolozi (Digitaria umfolozi). O experimento foi conduzido na fazenda experimental Campus Rural, São Cristóvão, SE. Observou-se diferença significativa (P<0,0001) nos teores de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), carboidratos não fibrosos (CNF), hemicelulose, fibra em detergente ácido (FDA), celulose e lignina. O capim Andropogon apresentou maiores teores de MS, MO, PB, FDA e lignina. O capim MG-5 apresentou maiores teores de CNF e celulose. Ob-servou-se diferença significativa (P=0,0002 e P=0,0004) na taxa de desaparecimento da MS e MO, respectivamente. Já, as espécies D. umfolozi e Humidicola apresentaram os maiores percentuais de desaparecimento da MS e MO, sendo que as forrageiras irrigadas foram maiores que as não irrigadas. Observou-se diferença significativa no volume acumulado de gás, onde os capins An-dropogon e MG-5 apresentaram maiores valores que os demais. Também foi observada diferença significativa nos parâmetros fermentativos, sendo que o capim Andropogon apresentou menores volumes e taxas de produção de gás das frações de rápida e lenta degradação, bem como maior lag time. A irrigação não afeta os parâmetros fermentativos das forrageiras e reduz o teor de matéria seca e proteína bruta das mesmas. O capim Andropogon apresenta maior teor proteico e de ligni-na, e menor teor de carboidratos não fibrosos, o que resultou em redução dos parâmetros fermen-tativos e da produção de gás acumulada ao longo do tempo...

Ruminal kinetics of tropical forrages submitted or not to irrigation / Cinética ruminal de forrageiras tropicais submetidas ou não a sistema de irrigação

This study evaluated the chemical composition and kinetics of ruminal fermentation of four forage species submitted or not to irrigation. The species evaluated were Urochloa brizantha cv. MG5 (MG-5), Andropogon gayanus (Andropogon), Urochloa humidicola (Humidicola), and Digitaria umfolozi. The experiment was conducted on the Campus Rural experimental farm, São Cristóvão, SE. Significant differences (P<0.0001) were observed in the content of dry matter (DM), organic matter (OM), crude protein (CP), nonfibrous carbohydrates (NFC), hemicellulose, acid detergent fiber (ADF), cellulose, and lignin. Andropogon exhibited higher DM, OM, CP, ADF and lignin concentrations. NFC and cellulose content was higher in MG-5 grass. A significant difference (P=0.0002 and P=0.0004) was observed in the rate of DM and OM disappearance, respectively. These rates were higher in D. umfolozi and Humidicola, as well as in irrigated versus non-irrigated forages. There was a significant difference in cumulative gas volume which was higher in Andropogon and MG-5 compared to the other forages. Significant differences were also found in the fermentation parameters, with Andropogon grass exhibiting a lower volume and rate of gas production from the fractions of fast and slow digestion, as well as a higher lag time. Irrigation does not affect the fermentation parameters of forages and reduces their DM and CP content. The higher protein and lignin content and lower NFC content observed in Andropogon reduced fermentation parameters and cumulative gas production over time. Humidicola exhibits a higher volume of gas produced, as well as a higher gas volume from the faster- and slower-digesting fractions and the highest gas production from these fractions.(AU)

Avaliou-se a composição química e a cinética de fermentação ruminal de quatro es-pécies forrageiras submetidas ou não à irrigação. As espécies avaliadas foram Urochloa brizantha cv. MG5 (MG-5), Andropogon gayanus (Andropogon), Urochloa humidicola (Humidicola) e Digitaria umfolozi (Digitaria umfolozi). O experimento foi conduzido na fazenda experimental Campus Rural, São Cristóvão, SE. Observou-se diferença significativa (P<0,0001) nos teores de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), carboidratos não fibrosos (CNF), hemicelulose, fibra em detergente ácido (FDA), celulose e lignina. O capim Andropogon apresentou maiores teores de MS, MO, PB, FDA e lignina. O capim MG-5 apresentou maiores teores de CNF e celulose. Ob-servou-se diferença significativa (P=0,0002 e P=0,0004) na taxa de desaparecimento da MS e MO, respectivamente. Já, as espécies D. umfolozi e Humidicola apresentaram os maiores percentuais de desaparecimento da MS e MO, sendo que as forrageiras irrigadas foram maiores que as não irrigadas. Observou-se diferença significativa no volume acumulado de gás, onde os capins An-dropogon e MG-5 apresentaram maiores valores que os demais. Também foi observada diferença significativa nos parâmetros fermentativos, sendo que o capim Andropogon apresentou menores volumes e taxas de produção de gás das frações de rápida e lenta degradação, bem como maior lag time. A irrigação não afeta os parâmetros fermentativos das forrageiras e reduz o teor de matéria seca e proteína bruta das mesmas. O capim Andropogon apresenta maior teor proteico e de ligni-na, e menor teor de carboidratos não fibrosos, o que resultou em redução dos parâmetros fermen-tativos e da produção de gás acumulada ao longo do tempo...(AU)