Pastures established using buffelgrass (Cenchrus ciliaris L.) have shown heterogeneous responses in terms of forage production and permanence. A good alternative for determining establishment sites and predict trends in buffelgrass conditions is the use of simulation models. The objectives of this research were to determine the factors that regulate successfulness in buffelgrass pastures and to develop a model to determine suitability in areas managed for buffelgrass pastures, based on environmental, ecological, and management variables. Above ground biomass production was considered to determine suitability in sites with buffelgrass. Eight ranches with different geographic locations, environmental situations, and management conditions were sampled as preliminary study sites to measure and model plant production. The resulting model was used to estimate plant production in the 37 sampling sites of the study areas. Results of the study indicate that basal area is a good modeling parameter to estimate production in buffelgrass plants. I also found that plant production in buffelgrass is negatively affected by population density. I concluded that there exist a positive correlation between pasture management and buffelgrass plant production. Correlation analyses demonstrate that there exist significant correlations between Pasture Condition Index (PCI) and mean annual temperatures, aspect, pasture age, nitrogen and sodium content. However, after performing stepwise regressions, only three variables were significant: pasture age (PA), nitrogen content (N2), and mean annual temperature (MAT); the last two, produce a negative response on PCI.

Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2017-04-13T13:49:42Z No. of bitstreams: 1 GenildoFP_TESE.pdf: 914555 bytes, checksum: d228a0712f89f6d40a7d44bfd5b02841 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-04-13T14:40:42Z (GMT) No. of bitstreams: 1 GenildoFP_TESE.pdf: 914555 bytes, checksum: d228a0712f89f6d40a7d44bfd5b02841 (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-04-13T14:43:38Z (GMT) No. of bitstreams: 1 GenildoFP_TESE.pdf: 914555 bytes, checksum: d228a0712f89f6d40a7d44bfd5b02841 (MD5) / Made available in DSpace on 2017-04-13T14:44:16Z (GMT). No. of bitstreams: 1 GenildoFP_TESE.pdf: 914555 bytes, checksum: d228a0712f89f6d40a7d44bfd5b02841 (MD5) Previous issue date: 2016-04-17 / The aim of this thesis was to evaluate the performance of Andropogon grasses (Andropogon gayanus Kunth), Buffel (Cenchrus ciliary L.) cv. Grass and Massai (Panicum maximum x Panicum infestum) at ages 21, 35, 49 and 63 days. The experiments were carried out at the Federal Institute of Education, Science and Technology of Rio Grande do Norte - IFRN Campus Apodi, in the period from June to December 2014. The evaluations were carried out in two stages, which yielded three scientific papers. In the first stage, information was addressed regarding the forage species, which were emphasized morphogenetic and structural characteristics and the production and chemical composition of corn in different regrowth ages. In the second stage, it was shown the evaluation of animal performance using hay of the three studied forages, which analyzed the nutrient intake, feeding behavior and sheep performance. For morphogenic and structural evaluation the andropogon presented late vegetative development, contrary to the development presented by buffel grass. Grasses Andropogon, Buffel and Massai increase the production of dry matter with advancing age of regrowth, the andropogon showed higher growth rates of dry matter (469.41%). It occurred only difference between the grasses and Andropogon Massai, from 49 days of regrowth. The crude protein, neutral detergent fiber and lignin components were more varied with increasing regrowth period in all forage species. In assessing the performance of animals fed with hay, it was observed that the regrowth ages influenced rumination, reducing its efficiency with advancing age. The daily weight gain of the animals fed the massaigrass hay and grass Andropogon hay did not differ, but differed from the buffel grass hay. The daily weight gain was not influenced by the age of grasses. Overall analysis showed that the thesis information interrelation helped to determine the best way to choose the forage species to the region, reaching the conclusion that in the conditions, the Massai and Andropogon grasses stood by vegetative best performance and best responses to animals. / O objetivo desta Tese foi avaliar o desempenho produtivo dos capins Andropogon (Andropogon gayanus Kunth), Buffel (Cenchrus ciliares L.) cv. Grass e Massai (Panicum maximum x Panicum infestum) nas idades de 21, 35, 49 e 63 dias. Os experimentos foram desenvolvidos no Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte – IFRN, Campus Apodi, no período de junho a dezembro de 2014. As avaliações foram realizadas em duas etapas, que geraram três artigos científicos. Na primeira etapa, foram abordadas informações referentes às espécies forrageiras, onde foram enfatizadas as características morfogênicas e estruturais e a produção e composição química das gramíneas nas diferentes idades de rebrota. Na segunda etapa, foi evidenciada a avaliação do desempenho animal utilizando o feno das três forrageiras estudadas, onde foi analisado o consumo de nutrientes, comportamento ingestivo e o desempenho de ovinos. Para avaliação morfogênica e estrutural o capim-andropogon apresentou desenvolvimento vegetativo tardio, contrário ao desenvolvimento apresentado pelo capim-buffel. Os capins Andropogon, Buffel e Massai aumentam a produção de matéria seca com o avanço da idade de rebrota, o capim-andropogon apresentou maiores crescimentos de matéria seca (469,41%). Ocorreu diferença apenas entre os capins Massai e Andropogon, a partir dos 49 dias de rebrota. A proteína bruta, a fibra em detergente neutro e a lignina foram os componentes que mais variaram com o aumento do período de rebrota em todas as espécies forrageiras estudadas. Na avaliação de desempenho dos animais, alimentados com feno, foi observado que as idades de rebrota influenciaram a ruminação, diminuindo sua eficiência com o avanço da idade. O ganho de peso diário dos animais alimentados com o feno de capim-massai e feno de capim-andropogon não diferiram entre si, mas diferiram do feno de capim buffel. O ganho de peso diário não foi influenciado pela idade dos capins. Em análise geral, observou-se que a inter-relação de informações da Tese contribuiu para determinar a melhor forma de eleger a espécie forrageira para a região, chegando-se a conclusão que, nas condições apresentadas, os capins Massai e Andropogon se destacaram pelo melhor desempenho vegetativo e melhores respostas aos animais / 2017-04-13

Submitted by Rebeka Godeiro (rebeka_carvalho@hotmail.com) on 2018-05-21T12:49:59Z No. of bitstreams: 1 ALBERTO JEFFERSON DA SILVA MACÊDO - DISSETAÇÃO ZOOTECNIA 2018.pdf: 3604549 bytes, checksum: cc2db5d074017596cb0db0a6266af30d (MD5) / Made available in DSpace on 2018-05-21T12:49:59Z (GMT). No. of bitstreams: 1 ALBERTO JEFFERSON DA SILVA MACÊDO - DISSETAÇÃO ZOOTECNIA 2018.pdf: 3604549 bytes, checksum: cc2db5d074017596cb0db0a6266af30d (MD5) Previous issue date: 2018-02-20 / Capes / Essa dissertação foi composta por dois experimentos. No primeiro experimento teve como objetivo avaliar o potencial agronômico e características morfológicas de 34 genótipos de palma destinadas a produção de forragem. Os genótipos foram implantados em delineamento em blocos completos casualizados, com 34 tratamentos e três repetições. Após 330 dias de cultivo realizou-se medições biométricas das características morfológicas, verificação de mortalidade, ocorrência de pragas e doenças e corte das plantas para aferição da produção agronômica. A produção de massa verde se correlacionou com produção de massa seca, acúmulo de água, eficiência de uso da água, acúmulo de água e número de cladódio por planta. Os genótipos indicados para cultivo são Negro Michoacan (V07), Tamazunchale (V12), Califórnia (V14), Orelha de Elefante Mexicana (V17) e Amarillo 2289 (T32) por terem apresentado maiores produções de massa seca e verde, como também maiores acúmulo de água, eficiência de uso da água e capacidade de suporte. No segundo experimento objetivou-se avaliar o padrão de fermentação e a degradabilidade in situ da matéria seca de silagens sob a forma de ração. Cinco rações foram formuladas com base em palma forrageira (Opuntia ficus-indica Mill cv. Gigante) e capim-buffel (Cenchrus ciliaris). O delineamento experimental foi inteiramente casualizado, com cinco tratamentos e três repetições em que as rações diferiram na proporção de capim-buffel (0, 15, 25, 30 e 35%, com base na matéria natural). Observou-se efeito para a composição química das rações, todos os teores de matéria seca (MS) estavam dentro da faixa ideal para uma adequada fermentação. Não houve efeito para concentração de nitrogênio amoniacal. Houve efeito para recuperação da matéria seca (RMS), que variou de 96,3 a 99,9%. Os valores de pH diminuíram à medida que o tempo de abertura (dias) foi prolongado. Os teores de ácidos orgânicos diferiram em todas as rações. No entanto, em geral, todas as rações apresentaram conteúdo de ácido láctico satisfatório. À medida que aumentou a proporção de capim-buffel nas rações, a degradação da MS diminuiu. Com base no perfil de fermentação, perdas e composição química, a ração com maior proporção de palma forrageira pode ser recomendada para produção de silagem. / This dissertation was composed by two experiments. In the first experiment, the objective was to evaluate the agronomic potential and morphological characteristics of 34 cactus pear genotypes destined for forage production. The genotypes were implanted in a randomized complete block design, with 34 treatments and three replications. After 330 days of cultivation, biometric measurements of the morphological characteristics, mortality check, pest and disease occurrence, and crop cutting were performed for agronomic production. Green mass production correlated with dry mass production, water accumulation, water use efficiency, water accumulation and cladode number per plant. The genotypes indicated for cultivation are Negro Michoacan (V07), Tamazunchale (V12), Califórnia (V14), Orelha de Elefante Mexicana (V17) e Amarillo 2289 (T32) for having presented higher yields of dry and green mass, as well as greater accumulation of water, water use efficiency and carrying capacity. In the second experiment, the objective was to evaluate the fermentation pattern and the in situ degradability of dry matter of silages in the form of diet. Five diets were formulated based on spineless cactus (Opuntia ficus-indica Mill cv. Gigante) and buffelgrass (Cenchrus ciliaris). The experimental design was completely randomized, with five treatments and three replications in which the diets differed in the proportion of buffelgrass (0, 15, 25, 30 and 35%, based on natural matter). Effect was observed for the chemical composition of the diets, with all dry matter (DM) contents were within the ideal range for adequate fermentation. There was no effect on ammonia nitrogen concentration. There was effect for dry matter recovery (RMD), which ranged from 96.3 to 99.9%. The pH values decreased as the opening time (days) was prolonged. The levels of organic acids differed in all diets. However, in general, all diets had satisfactory lactic acid content. As the proportion of buffelgrass increased in diets, the degradation of DM decreased. Based on the profile of fermentation, losses and chemical composition, the diet with higher a proportion of spineless cactus can be recommended for silage production.

Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2008.

Buffelgrass (Cenchrus ciliaris L.) is an invasive, perennial, C₄ bunchgrass. Buffelgrass has a rapid invasion rate, a tendency to displace native vegetation, and presents a fire risk to native plant communities, adjacent developed areas and their associated infrastructure. Mechanical control is impractical and unable to keep pace with regional spread. Chemical control has offered the most promise for successful and cost-effective management on a regional scale. The predominant herbicide used to control buffelgrass is glyphosate, which requires active vegetative growth when applied for optimum uptake and translocation to meristematic tissue. The timing and duration of active growth is difficult to predict. In this dissertation I addressed three related topics to improve effectiveness of buffelgrass management in the Sonoran Desert. First, I used digital time-lapse photography and weather data to predict the timing and length of future active growth based on day of year and antecedent weather at three sites in the Sonoran Desert near Tucson, AZ that were representative of habitats currently infested by buffelgrass in the region. I was able to correctly predict greenness above or below a threshold of herbicide susceptibility at 81 to 95% for a basin floor site and at 61-88% for slope sites. Second, I evaluated the effects of different rates of two herbicides (imazapic and clethodim), alone or in combination with different rates of glyphosate, for pre- (imazapic only) and postemergence control of buffelgrass. I found a minimum glyphosate application rate of 2.52 kg ae ha⁻¹ glyphosate consistently killed mature buffelgrass plants; clethodim at had no effect on mature buffelgrass; and imazapyr was successful in killing mature plants when applied during the dormant season at 0.56 kg ae ha⁻¹ and provided preemergence control. Imazapic severely damaged but did not kill mature buffelgrass plants at the maximum label rate of 0.21 kg ae ha⁻¹. Finally, we evaluated results from a helicopter broadcast herbicide application trial conducted in the Tucson Mountains. We demonstrated that most species and life forms were less affected than buffelgrass to glyphosate deposition rates achieved in the study, but asserted that procedural changes were necessary to achieve effective buffelgrass control.

Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2008.

Thesis (Ph.D. (Botany))--North-West University, Potchefstroom Campus, 2008.

Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-04T12:16:19Z No. of bitstreams: 2 TESE Laerte Bezerra de Amorim.pdf: 3203495 bytes, checksum: 277a0e1e0001bdfe4d79c44881220a6f (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-04T12:16:19Z (GMT). No. of bitstreams: 2 TESE Laerte Bezerra de Amorim.pdf: 3203495 bytes, checksum: 277a0e1e0001bdfe4d79c44881220a6f (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2013 / CAPES;CISA;INSA / A precipitação pluvial é quase sempre a única fonte de abastecimento de água em zonas áridas e semiáridas tropicais e, portanto, desempenha um papel relevante na sustentabilidade dos ecossistemas. A escassez e a irregularidade da distribuição pluvial provoca sério estresse hídrico nas plantas, afetando a produção de biomassa e a perpetuação das espécies, sobretudo as menos adaptadas às condições áridas e semiáridas. Em meio a essa problemática, foram realizadas duas investigações, de fevereiro de 2011 a junho de 2012, uma que avaliou a partição das chuvas (interceptação pelas plantas e precipitação efetiva) e sua influência no armazenamento de água no solo em áreas de caatinga e de capim-buffel (Cenchrus ciliaris) e outra que avaliou o potencial hídrico do xilema (Ψw) na antemanhã (Ψwa) e diurno (Ψwd) do Croton blanchetianus (marmeleiro), Poincianella pyramidalis (catingueira) e Mimosa ophthalmocentra (jurema-de-imbira) ao longo de diferentes estádios fenológicos, quantidades de água armazenada no solo e demandas evaporativas. As interceptações pluviais foram medidas em áreas de caatinga raleada, caatinga densa e de capim-buffel. A intensidade pluviométrica variou de 0,2 a 85 mm h-1 (n=714) com 55% dos eventos chuvosos entre 0,2 e 1 mm h-1.O total pluvial acumulado livre de interceptação foi de 1.060 m, desse montante, 87% atingiram de forma direta (sem interceptação) a superfície do solo na caatinga raleada, 81% na caatinga densa, 61% no C. ciliaris e 40% na caatinga densa com bromélias. Esses diferentes volumes de entrada de água no solo provocaram diferentes armazenamentos de água nas camadas de 0-10, 10-20 20-30 e 30-40 cm de solo. A secagem da água armazenada em termos proporcionais em 0-40 cm de solo foi maior na caatinga densa (média da área com e sem bromélias), seguida da caatinga raleada e da área com C. ciliaris. O decréscimo mais lento da água armazenada na área de capim-buffel em relação à área de caatinga pode está relacionado com o menor consumo de água dessa gramínea e a evaporação de água no solo, e a alta adaptação do C. ciliaris à escassez hídrica. As medidas de estresse hídrico das espécies da caatinga, nesse estudo mensurado pelo Ψw usando o método da câmara de pressão de Scholander, variaram na antemanhã de -0,10 a -2,23 MPa em C. blanchetianus, de -0,23 a -2,31 MPa em P. pyramidalis e de -0,32 a -3,65 MPa em M. ophthalmocentra. No período diurno o Ψwd atingiu -5,60 Mpa (M. ophthalmocentra) e as diferenças de Ψw entre as espécies foram mais frequentes, sobretudo nas horas de maior demanda hídrica. O comportamento Ψwd nas três espécies foi semelhante, iniciando o dia com os valores mais altos e diminuindo gradativamente até próximo do meio dia. O Ψw total das espécies estudadas demonstrou forte relação com o estádio fenológico, sobretudo a presença ou ausência de folhas.

The aim of the study was to determine if significant differences, in terms of grazing parameters, intake, animal performane and digestibility, existed between foggage of Cenchrus ciliaris cv. Molopo and Cenchrus ciliaris cv. Gayndah. A grazing trial as well as a partial digestibility study was done with sheep. The following parameters were used: grazing parameters (dry matter availability and structure of the grazing), qualitative and quantitative intake, animal production and partial digestiblity. The grazing trial was conducted over two years and further divided into two separate periods of utilisation, middle and late winter. The second trial was a partial digestibility experiment conducted during the second year. In terms of the production parameters of the two varieties: dry material production and sward length of C. ciliaris cv. Molopo was constantly higher than that of C. ciliaris cv. Gayndah. In the grazing experiment the quality of selected material did not differ between C. ciliaris cv. Gayndah and Molopo. Differences in most parameters were not significant. Experimental animals grazing Gayndah selected a diet with higher N- and NDF-concentrations, as opposed to animals grazing Molopo. The same trend continued during the second year but only for N-concentration. In terms of quantitative observations in the grazing experiment the intakes of the two varieties were high for the whole duration of the trial. Only during the "out"-phase of period 1 in 1991, animals on C. ciliaris cv. Molopo couldn’t maintain an intake to meet maintenance requirements. Experimental animals gained weight in the first period of grazing of the first year of the study but not during the rest of the trial. Although intake was high in the other periods, these intakes didn’t support growth or maintenance. This suggests that supplementation in the form of a lick could address possible deficiencies. In the partial digestion trial animals grazing C. ciliaris cv. Gayndah, as opposed to animals on cv. Molopo, selected a better quality material but quantitatively there were no significant differences. For both varieties the amount of organic material consumed wasn’t adequate to meet maintenance requirements. There were no significant differences in the partial digestibility of organic material or nitrogen. Animals on both varieties were in a negative nitrogen balance. / Dissertation (MSc Agric (Animal and Wildlife Sciences))--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-07-13T23:53:47Z No. of bitstreams: 1 Disserta??o final_completa_pdf.pdf: 1029289 bytes, checksum: 67d8eb9bd97c05071808a15be37032a8 (MD5) / Made available in DSpace on 2016-07-13T23:53:47Z (GMT). No. of bitstreams: 1 Disserta??o final_completa_pdf.pdf: 1029289 bytes, checksum: 67d8eb9bd97c05071808a15be37032a8 (MD5) Previous issue date: 2015-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The objective of this study was to characterize morfoagronomicamente buffel grass accesses the active germplasm bank (BAG) of Cenchrus of the Embrapa Semi?rido checking the variability and efficiency of characters in carrier two consecutive cuts. We used 26 hits and 4 buffel grass cultivars in randomized blocks with three replications and with plot nine plants per access, taking as the central portion useful plant in the plot. The evaluations were performed after two cuts of the aerial part of Buffel grass, each evaluation was performed 90 days after each cut. The characterization of the accessions was based on 15 quantitative and qualitative morphological descriptors. Quantitative descriptors were submitted to analysis of individual and combined variance, considering the two cuts of treatment and then applied the Scott-Knott test at 5% probability. Qualitative descriptors were submitted to descriptive analysis. For divergence analyzes both quantitative and qualitative descriptors were grouped using the methods of Tocher and UPGMA from the Mahalanobis distance (D2). In addition, a dendrogram and calculated the relative importance of characters for the divergence. In the combined analysis, the effects of access and cutting were significant for almost all the features. This result indicates genetic heterogeneity among the accessions and the felling indicates mainly differences in management culture conditions and growth rate of each access in each mowing season. It was also observed significant effect of genotype x environment interaction at 1% probability for three descriptors (NPT, and LIN QIN) and other descriptors (APL, ECO, COF, LFO and CIN) these effects were not significant. The accessions were separated into two groups, the first consisting of 25 hits and 4 cultivars and the second composed of the access 138. The number of tillers / shoot, followed by number of inflorescence and color of the seeds were the most relevant characters in separation of access. / O objetivo deste trabalho foi caracterizar morfoagronomicamente acessos de capim buffel do Banco ativo de germoplasma (BAG) de Cenchrus da Embrapa Semi?rido verificando a variabilidade e efici?ncia dos caracteres nos acessos em dois cortes consecutivos. Foram utilizados 26 acessos e quatro cultivares de capim buffel em delineamento em blocos ao acaso com tr?s repeti??es com parcela de nove plantas por acesso, tomando como parcela ?til a planta central dentro da parcela. As avalia??es foram realizadas ap?s dois cortes da parte a?rea do capim buffel, cada avalia??o foi realizada 90 dias ap?s cada corte. A caracteriza??o dos acessos foi realizada com base em 15 descritores morfoagron?micos quantitativos e qualitativos. Os descritores quantitativos foram submetidos ? an?lise de vari?ncia univariada individual e conjunta, considerando os dois cortes dos tratamentos e, em seguida, aplicado o teste de Scott-Knott a 5% de probabilidade. Os descritores qualitativos foram submetidos a an?lise descritiva. Para as an?lises de diverg?ncia tanto descritores quantitativos quanto qualitativos foram agrupados utilizando-se os m?todos de Tocher e UPGMA, a partir da dist?ncia generalizada de Mahalanobis (D2). Foi estabelecido tamb?m um dendograma e calculada a import?ncia relativa dos caracteres para a diverg?ncia. Na an?lise conjunta, os efeitos de acesso e corte foram significativos para quase todas as caracter?sticas. Esse resultado indica heterogeneidade gen?tica entre os acessos e quanto ao corte indica, principalmente, diferen?as nas condi??es de manejo da cultura e da velocidade de crescimento de cada acesso em cada ?poca de corte. Tamb?m foi observado efeito significativo da intera??o gen?tipos x ambientes ao n?vel de 1% de probabilidade para tr?s descritores (NPT, LIN e QIN) e para os demais descritores (APL, ECO, COF, LFO e CIN) estes efeitos n?o foram significativos. Os acessos foram separados em dois grandes grupos, o primeiro composto por 25 acessos e quatro cultivares e o segundo composto apenas pelo acesso 138. O n?mero de perfilhos/touceira, seguida por quantidade de infloresc?ncia e cor das sementes foram os caracteres de maior relev?ncia na separa??o dos acessos.