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Atributos químicos e físicos de um Nitossolo Vermelho Eutrófico léptico argiloso foram avaliados em Passo Fundo (RS) em um experimento sobre o desempenho agronômico de três gramíneas perenes de verão (capim quicuio, capim elefante e capim Tifton 68) para a produção de leite após duas estações de crescimento. O delineamento experimental foi em blocos ao acaso com quatro repetições. Avaliou-se também o solo sob floresta subtropical em área adjacente ao experimento. Os valores de pH, Al, Ca e Mg trocáveis, e P extraível diferiram, em algumas camadas, entre as pastagens estudadas. Algumas pastagens, em relação à floresta nativa favoreceram a elevação do teor de P, em todas as camadas avaliadas. Entre as pastagens, não houve diferença significativa para o teor de carbono do solo. Sob capins houve maior acúmulo de carbono, na camada de 0-20 cm do solo, em comparação à floresta. A densidade do solo e a resistência à penetração não diferiram entre as pastagens, em ambas as camadas, porém nas camadas de 0 a 5 cm e na de 10 a 15 cm, houve aumento desses valores, em relação à floresta subtropical. As porosidades totais e a macroporosidade não diferiram entre as três espécies de pastagens, mas houve redução dos valores em comparação com a floresta subtropical.Soil chemical and physical characteristics were evaluated on a Rhodic Nitisol Eutrophic clayey located in Passo Fundo, Rio Grande do Sul State, Brazil in a trial of agronomic performance of three perennial summer grasses (kikuyu grass, elephant grass and Tifton 68 grass) for milk production after two growing seasons. The trial used a complete randomized block design replicated three times. Soil samples were also taken in a fragment of subtropical forest near the experiment. Soil reaction (pH), aluminum, calcium, magnesium, and phosphorus varied according to the studied soil layer. Some grasses increased the level of phosphorus content in all layers. Pastures increased accumulated carbon levels in the 0-20 cm layer in comparison to subtropical forest. No differences among grass species were observed for soil organic matter contents. Soil bulk density and soil mechanical resistance did not differ among pastures in both sampling layers. However, in the 0-5 cm layer (and in the 10-15 cm), these values increased in comparison to the subtropical forest. Total porosity and macroporosity did not differ among of three grass species, but the values were respectively lower and greater in comparison to soil forest.

Se evaluó el efecto de la suplementación del pasto kikuyo con destilado de yuca obtenido como sub-producto en la elaboración de bioetanol a partir de la yuca sobre los principales parámetros de fermentación ruminal in vitro y su impacto sobre la producción y composición de la leche, consumo de materia seca del forraje y costos de producción. Los principales parámetros de fermentación ruminal in vitro a 24 horas de incubación fueron afectados positivamente por la suplementación con destilado de yuca. En el fermentador Rusitec, la suplementación con destilado y harina de yuca también afecto positivamente algunos de los parámetros de la fermentación ruminal y las poblaciones de algunos microorganismos ruminales (protozoos) y provocó una disminución en la concentración de N-NH3. Por otro lado, la suplementación de vacas lactantes con destilado de yuca no afectó la producción de leche ni su composición, así como tampoco el consumo de materia seca del forraje, los costos de producción fueron mayores en las vacas suplementadas con destilado de yuca y la relación beneficio:costo fue menor en dicho tratamiento debido a la experimentalidad del proceso de obtención del bioetanol a partir de la harina de yuca. Abstract: We evaluated the effect of supplementation of kikuyu grass with cassava distillate obtained as a by-product of the bioethanol production from cassava on the main rumen fermentation parameters in vitro and its impact on the production and milk composition, forage dry matter intake and production costs. The main rumen fermentation parameters in vitro at 24 hours of incubation were positively affected by supplementation with cassava distillate. In Rusitec fermenters, supplementation with distillate and cassava flour also positively affect some rumen fermentation parameter and some populations of rumen microorganisms (protozoa) and caused a decrease in the concentration of N-NH3. Supplementation of lactating dairy cows with cassava distillate did not affect milk production or composition, nor the forage dry matter intake, production costs were higher in cows supplemented with cassava distillate and the benefit to cost ratio was lower in such treatment due to experimentality of the process used for the bioethanol production from cassava flour. Maestría

This study examined the variation existing in naturalised populations of kikuyu grass (Pennisetum clandestinum Hochst. ex. Chiov) in Australia, as well as initiating a breeding programme aimed at producing new hybrid lines for the Australian turfgrass and agricultural market. The first part of the study examines the phenotypic variation which exists within kikuyu grass populations; the genotypic variation of those populations via DNA marking; and, the basis of male sterility within those populations. The second part examines kikuyu grass within a breeding perspective through pollen viability and storage; the potential presence of an endophyte within the seed; classical hybridisation of ecotypes through to field planting; and, whether the oomycete Verrucalvus flavofaciens can be controlled via a modern day fungicide programme. It also rewrites the history of kikuyu introduction, first seeding occurrence, and previously unrecorded importations into Australia. General observations record the first photographic images of kikuyu grass chromosomes. Significant phenotypic variation exists within naturalised kikuyu grass populations across Australia. From a collection of about 200 ecotypes 16 were selected for detailed study. Analysis of the ecotypes identified two lines from several which show great potential within the Australian turfgrass and agricultural market; the first selected at Grafton, NSW, which in the leaf width analysis displayed a leaf width over 18% finer than the mean; with the second selected at Morphettville, SA, which in the stolon width analysis displayed a stolon width over 15% thicker than the mean. Both selections, as well as others, displayed positive traits which would appeal to a wide range of end users. Genetic investigations using RAPD marker techniques are undertaken on kikuyu for the first time. A total of thirteen decamer primers produced 195 markers of which 93.85% were polymorphic. Genotypic variation amongst the Australian selections was found to range from 28.8% - 82.4%. Relatedness between the cluster accessions used in the phenotypic analysis and the dendogram produced in the genetic analysis was not found. Male sterility within Australian kikuyu grass was determined to exist as a recessive condition. From the F1 population, 100% transformation from male sterile to fully fertile was observed; with the F2 population segregating into a 52.5% fully fertile, 47.5% male sterile. Negative interactions between parental lines were observed. Kikuyu grass pollen is most viable in the first few hours after shedding, and deteriorates significantly within 24 hours, even at low temperatures, if it is stored. Pollen viability varies amongst genotypes. Prior additions of dry colloidal material does not assist in storage capabilities. Investigations into seedling mortality of kikuyu identified the possible presence of an endophyte within the seed. Surface sterilisation techniques provided no control, with an addition of 0.1% PPM to the base agar mixture the most effective form of control. Intercellular hyphae were identified and photographed after staining with Rose Bengal. Hybridisation studies of kikuyu grass resulted in several potential lines worthy of continued analysis. Selections from varying growing environments around Australia were hybridised with three pollen parents derived from chemical mutagenesis producing a total of 349 hybrid F2 seeds. Germination and screening in the glasshouse resulted in 14 hybrid lines being field planted alongside cv. ‘Whittet’ for comparison. The opportunity exists within the turfgrass market for elite lines of kikuyu, which will cover a wide range of uses from golf course tees and fairways, sporting grounds and race tracks, to pasture and commercial use. Efficacy with modern day fungicides in vitro was found not successful in controlling Kikuyu Yellows (Verrucalvus flavofaciens). Resistance of kikuyu grass to the oomycete will have to come in the form of genetically resistant cultivars; production of a specific fungicide; or both.

Atributos químicos e físicos de um Nitossolo Vermelho Eutrófico léptico argiloso foram avaliados em Passo Fundo (RS) em um experimento sobre o desempenho agronômico de três gramíneas perenes de verão (capim quicuio, capim elefante e capim Tifton 68) para a produção de leite após duas estações de crescimento. O delineamento experimental foi em blocos ao acaso com quatro repetições. Avaliou-se também o solo sob floresta subtropical em área adjacente ao experimento. Os valores de pH, Al, Ca e Mg trocáveis, e P extraível diferiram, em algumas camadas, entre as pastagens estudadas. Algumas pastagens, em relação à floresta nativa favoreceram a elevação do teor de P, em todas as camadas avaliadas. Entre as pastagens, não houve diferença significativa para o teor de carbono do solo. Sob capins houve maior acúmulo de carbono, na camada de 0-20 cm do solo, em comparação à floresta. A densidade do solo e a resistência à penetração não diferiram entre as pastagens, em ambas as camadas, porém nas camadas de 0 a 5 cm e na de 10 a 15 cm, houve aumento desses valores, em relação à floresta subtropical. As porosidades totais e a macroporosidade não diferiram entre as três espécies de pastagens, mas houve redução dos valores em comparação com a floresta subtropical. Soil chemical and physical characteristics were evaluated on a Rhodic Nitisol Eutrophic clayey located in Passo Fundo, Rio Grande do Sul State, Brazil in a trial of agronomic performance of three perennial summer grasses (kikuyu grass, elephant grass and Tifton 68 grass) for milk production after two growing seasons. The trial used a complete randomized block design replicated three times. Soil samples were also taken in a fragment of subtropical forest near the experiment. Soil reaction (pH), aluminum, calcium, magnesium, and phosphorus varied according to the studied soil layer. Some grasses increased the level of phosphorus content in all layers. Pastures increased accumulated carbon levels in the 0-20 cm layer in comparison to subtropical forest. No differences among grass species were observed for soil organic matter contents. Soil bulk density and soil mechanical resistance did not differ among pastures in both sampling layers. However, in the 0-5 cm layer (and in the 10-15 cm), these values increased in comparison to the subtropical forest. Total porosity and macroporosity did not differ among of three grass species, but the values were respectively lower and greater in comparison to soil forest.

En el presente estudio se determinó y evaluó la producción de biomasa aérea (g MS/m2), composición botánica, calidad nutricional, y producción y calidad de leche en dos tipos de pasturas para clima frío. El ensayo se realizó en el centro agropecuario Marengo de la Universidad Nacional en Mosquera, Cundinamarca, donde se evaluaron dos pasturas, una de mezcla de kikuyo (Pennisetum clandestinum) y festuca alta (Festuca arundinacea) la segunda, una mezcla de festuca alta y la leguminosa trébol pata de pájaro (Lotus uliginosus) con un área de 1 ha cada una. Se empleó un diseño al azar con la vaca como unidad experimental y la pastura como tratamiento. Se usaron 5 vacas Holstein (PV 580 kg) entre 2 y 4 partos de segundo tercio de lactancia para cada tratamiento durante un periodo experimental de 14 días, 7 de acostumbramiento y 7 de mediciones. En cada pastura se determinó la producción de biomasa aérea (g MS/m2), composición botánica (%), calidad nutricional (PC, FDN, FDA, DIV MS), y se evaluó la producción (lt/día) y calidad de leche (porcentaje de grasa, proteína, caseína, sólidos). Aunque no se realizó comparación estadística para la producción de biomasa, la mayor producción fue observada en la pastura asociada; también en cuanto a la calidad nutricional la principal diferencia se observó en el contenido de proteína, siendo mayor en la pastura asociada. Se observaron mayores valores en producción de leche, caseína y proteína en la pastura de gramínea más leguminosa (P and lt; 0,05), sin diferencias para grasa y sólidos totales (P and gt; 0,05). Se puede concluir que las pasturas asociadas de gramínea más leguminosa mejoran los valores de producción y proteína en la leche. In the present study was determined and assessed the aerial biomass (g MS/m2), botanical composition, nutritional quality and production and quality of milk in two types of pasture for cold weather. The experiment was carried out in Marengo Central Agriculture of the National University of Colombia in Mosquera, Cundinamarca, where a mixture of kikuyu grass (Pennisetum clandestinum) and tall fescue (Festuca arundinacea) and other of tall fescue mixed with birdsfoot trefoil (Lotus uliginosus) legume was evaluated, in a hectare by each pasture. Employing a completely randomized design how the cow was a experimental unit and the pasture was a treatment. 5 Holstein cows (PV 580 kg) between two and four birth in the mid lactation for each treatment for a trial period of 15 days was used, 7 days of adaptation and 7 days of measurements. In each pasture aerial biomass (g MS/m2), botanical composition (%), nutritional quality (PC, ND F, FDA DIV MS), milk production (lt/day) and milk quality (% fat, protein, casein and solids) was determined. Although no statistical comparison was done for biomass production, the greater production was the mixed pasture, also with regard to the nutritional quality the main difference was observed in the protein content, being higher in the mixed pasture. Higher values were observed in milk production, casein and protein in the mixed pasture (P 0.05) contents. We concluded that the pastures mixed grass + legume improve the milk production and protein in milk values.

O experimento foi conduzido a campo com o objetivo de determinar as frações de fósforo (P) em gramíneas forrageiras tropicais, aos 35 dias de idade, sob fontes e doses de P. Foi utilizado o delineamento experimental em blocos ao acaso, com três repetições, com os tratamentos dispostos em um esquema de parcelas subsubdivididas, sendo alocadas nas parcelas as gramíneas (capim-coastcross, capim-florona e capim-quicuio); nas subparcelas as fontes de P (Superfosfato Triplo, Fosfato Reativo, Arad e Fosfato Natural, Araxá) e nas subsubparcelas as doses de P (0, 40, 80 e 120 kg/ha de P2O5). As variáveis estudadas foram as frações de P, P total solúvel, P inorgânico e P orgânico. O capim-quicuio apresentou maior (P