RESUMO Solos alcalinos podem apresentar grandes quantidades de carbonatos de cálcio, houve precipitação de fosfato de cálcio insolúvel. O objetivo da pesquisa foi determinar a resposta da aplicação de fósforo no conteúdo nutricional do tecido foliar das pastagens Pennisetum purpureum e dois híbridos com espécies do gênero Pennisetum em solos calcários do Departamento de Córdoba-Colômbia. Este estudo foi realizado em estufas e laboratórios da Faculdade de Ciências Agrárias da Universidade de Córdoba, localizada no município de Montería. O solo calcário foi coletado em dois locais do Departamento de Córdoba fazenda Vista Hermosa, e o segundo local correspondeu à localidade de Carolina, e Planeta Rica. Utilizou-se o delineamento inteiramente casualizado com arranjo fatorial 2x3x6 com quatro repetições: dois tipos de solo (Vista Hermosa e Carolina); três gramíneas King Grass (Híbrido entre Pennisetum purpureum y Pennisetum typhoides), Cuba OM-22 (Hibrido entre Pennisetum purpureum Cuba CT-169 y Pennisetum glaucum Tiffton) e elefante roxo (Pennisetum purpureum); seis doses de fosfato (0, 80, 150, 250, 400 e 650 kg ha-1) aplicado na forma de P2O5. A aplicação de P no solo não aumentou os teores de N, K, Ca e Mg na pastagem King Grass, Pennisetum purpureum e Cuba OM-22 estabelecidos nos solos calcários de Vista Hermosa e Carolina. Nos solos calcários da Carolina, King Grass, Pennisetum purpureum e Cuba, OM-22 absorveram maiores quantidades de fósforo.

ABSTRACT Alkaline soils present large amounts of calcium carbonates, with precipitation of insoluble calcium phosphate. The objective of the research was to determine the effects of the P application on the nutrient levels of the foliar tissue of Pennisetum pastures in calcareous soils in Córdoba-Colombia. Soil samples were collected from two locations in the Department of Córdoba. A completely randomized design with a 2 x 3 x 6 factorial arrangement (Vista Hermosa and Carolina), there Pennisetum species (king grass, Cuba OM-22, and Pennisetum purpureum), and six P doses (0, 80, 150, 250, 400, and 650 kg ha-1), applied as P2O5, was used. The addition of P did not increase the contents of N, K, Ca, and Mg in the king grass, Pennisetum purpureum, and Cuba OM-22 pastures. However, in the calcareous soils of Carolina, king grass, Pennisetum purpureum, and Cuba, OM-22 absorbed higher amounts of P.

Resumen En vida libre, Odocoileus virginianus consume plantas con alto beneficio energético, pero en cautiverio, no se cuenta con una alimentación diversa que aumente su capacitad productiva. El objetivo fue evaluar el consumo y preferencia de ocho plantas por un grupo de venados en cautiverio con base en una prueba de cafetería. El experimento se desarrolló durante cinco días consecutivos con tres repeticiones, con un descanso de 15 días entre repetición, y consistió en ofrecer 1 kg de material vegetal de cada planta, se registró su consumo y se evaluó con un análisis de varianza y una prueba de Tukey; además, de cada planta, se estimaron sus características fisicoquímicas y bromatológicas y se relacionaron con el consumo mediante un análisis de regresión por mínimos cuadrados parciales. El consumo fue significativamente mayor en cuatro plantas: Zapoteca acuelata, Bidens pilosa, Pennisetum purpureum y Parthenium hysterophorus y su preferencia estuvo determinada por el contenido de fibra, proteína, °Brix y pH. Diversificar la alimentación de los venados en Unidades de Manejo para la Conservación de la Vida Silvestre (UMA) podría incrementar su productividad.

Abstract Wild white-tailed deer Odocoileus virginianus consume a diversity of high energy plants. Captive deer, however, do not have access to this diversity, which may affect their productive capacity. A cafeteria test was used to evaluate intake of and preference for eight plant species among captive deer in Veracruz, Mexico. Three replicates were done of five consecutive days of feeding with the selected plants followed by a 15-d evaluation period. One kilogram of material from each plant species was offered each day and intake recorded. Physicochemical analyses were done of all eight species. Intake results were evaluated with an analysis of variance and a Tukey test, and a partial least squares regression analysis was applied to relate intake to plant characteristics. Intake was highest for four plants: Zapoteca acuelata, Bidens pilosa, Pennisetum purpureum and Parthenium hysterophorus. Preference for these species was determined by their fiber and protein contents, and °Brix and pH levels. Diversifying the diet of captive deer could provide additional feed options for producers and increase animal productivity parameters.

RESUMO A utilização agrícola de fontes alternativas de água de qualidade inferior, tais como o reuso de águas de esgotos de origem doméstica, surge como opção para ampliar a disponibilidade hídrica, além de proporcionar o reaproveitamento de nutrientes e matéria orgânica, auxiliando na manutenção da fertilidade e produtividade do solo. Nesse contexto objetivou-se com este trabalho avaliar o crescimento, a produtividade e a nutrição do capim elefante irrigado com diferentes combinações de aplicação do esgoto doméstico tratado e água de poço. O delineamento experimental utilizado foi em blocos ao acaso, com seis tratamentos e quatro repetições, contendo 10 plantas em cada parcela. Os tratamentos consistiram em cinco combinações de aplicação do efluente doméstico tratado (EDT) e água de poço (AP): T1 (100% AP), T2 (25% EDT + 75% AP), T3 (50% EDT + 50% AP), T4 (75% EDT + 25% AP), T5 (100% EDT) e um tratamento adicional (T6) irrigado 100% com água de poço + adubação mineral (N-P-K) recomendada para o capim elefante. As variáveis analisadas foram: número de folhas, diâmetro do colmo, número de perfilhos, altura da planta, área foliar, massa fresca e seca da folha e do colmo, produtividades de massa fresca e seca, e o teor de macronutrientes na parte aérea da planta. Os tratamentos com maiores quantidades de EDT aplicado na irrigação foram os que mais se aproximaram das obtidas no tratamento cultivado convencionalmente, sendo os tratamentos com 50% ou mais de EDT estatisticamente iguais ao tratamento com cultivo convencional pelo teste de Tukey (p < 0,05).

ABSTRACT The agricultural use of alternative water sources of inferior quality, such as reusing the water from domestic sewage, is seen as one way of increasing water availability, in addition to allowing the reuse of nutrients and organic matter, thereby helping to maintain the fertility and productivity of the soil. The aim of this study, therefore, was to evaluate growth, productivity and nutrition in elephant grass irrigated with different combinations of treated domestic effluent and well water. The experimental design was of randomised blocks, with six treatments and four replications, containing 10 plants in each plot. The treatments comprised five combinations of treated domestic effluent (TDE) and well water (WW): T1 (100% WW), T2 (25% TDE + 75% WW), T3 (50% TDE + 50% WW), T4 (75% TDE + 25% WW), T5 (100% TDE), and an additional treatment (T6) of 100% well water + a mineral fertiliser (NPK) recommended for elephant grass. The following variables were analysed: number of leaves, stem diameter, number of tillers, plant height, leaf area, fresh and dry weight of the leaves and stems, fresh and dry weight production, and the macronutrient content of the aerial part of the plant. The treatments applying the greatest levels of TDE had the closest mean values to those obtained under the conventional treatment, while the treatments applying 50% or more TDE were statistically equal by Tukey’s test (p < 0.05) to the conventional treatment.

Abstract Grass species forage yield and nutritional value directly affect livestock production performance. They also vary in response to regional climate and soil conditions. Forage yield and nutritional value in Pennisetum purpureum cv. Cuba CT-115 were evaluated at five regrowth ages (30, 45, 60, 75 and 90 d) in three seasons (dry, rainy and northwinds). A completely randomized block design with repeated measures was used, with four replicates per treatment. In all three seasons, maximum height was reached at 75 d: 127.1 cm in the dry season, 151.6 cm in the rainy season and 137.0 cm the northwind season. Forage yield was highest (27.0 t DM ha-1) at 90 d in the rainy season, with a growth rate of 300.2 kg DM ha-1 d-1, 7.3% crude protein and 37.0% in situ digestibility of dry matter. The leaf:stem ratio was highest at 30 d in all seasons, with a 1.65 average value. Crude protein content was highest in the northwind season at 30 and 45 d, with a 15.6 % average value. In all three seasons, digestibility was highest at 30 (mean= 49.3 %), 45 (51.8 %) and 60 d (48.2 %). Based on forage yield, use of P. purpureum cv. Cuba CT-115 grass for open grazing is recommended for cutting at 90 days’ regrowth and based on its nutritional quality is recommended for grazing at 60 days’ regrowth, both during the rainy season.

Resumen Se evaluó el rendimiento de forraje y valor nutritivo del pasto Pennisetum purpureum cv Cuba CT-115, en cinco edades de rebrote: 30, 45, 60, 75 y 90 días, en tres épocas del año: seca, lluvias y nortes. Se utilizó un diseño de bloques completos al azar con medidas repetidas, con cuatro repeticiones por tratamiento. La mayor altura se registró a partir de los 75 días, en todas las épocas, con valores de 127.1, 151.6 y 137.0 cm, en seca, lluvias y nortes, respectivamente. El rendimiento más alto de forraje (27.0 t MS ha-1) se obtuvo a los 90 días en la época de lluvias, con una tasa de crecimiento (TC) de 300.2 kg MS ha-1 día-1, 7.3 % de proteína cruda (PC) y 37.0 % de degradación in situ de la materia seca (DIMS). La relación hoja:tallo fue mayor a los 30 días de rebrote, con un valor promedio de 1.65. El contenido de PC fue mayor en la época de nortes a 30 y 45 días, con un valor promedio de 15.6 %. La DIMS fue más alta a 30, 45 y 60 días, con valores promedio de 49.3, 51.8 y 48.2 %, respectivamente. Con base al rendimiento de forraje, se recomienda el uso del pasto Cuba CT-115 para corte a 90 días de rebrote durante la época de lluvias, mientras que, por su calidad nutricional, se recomienda su uso para pastoreo a 60 días de crecimiento después del corte.

RESUMO O cultivo de gramíneas em lodo de esgoto com aeração melhora a qualidade desse fertilizante, uma vez que o crescimento das raízes, a liberação de exsudatos e a oxigenação favorecem a mineralização dos nutrientes e a humificação da matéria orgânica. Assim, o presente trabalho teve como objetivo avaliar a decomposição de lodo de esgoto utilizando-se cultivo com gramínea e aeração para uso como adubo orgânico. O experimento foi realizado no delineamento em blocos casualizados com quatro repetições, num esquema fatorial 2 x 5, correspondendo à presença ou não de cultivo com Pennisetum purpureum em lodo de esgoto, combinado com cinco períodos de aeração: 0, 14, 28, 42 e 60 dias, com vazão de ar de 1.059 dm3.h−1.kg−1 de sólidos voláteis. As análises mostraram que a injeção de ar no lodo de esgoto não influenciou a decomposição da matéria orgânica e a realização de cultivo da gramínea em lodo de esgoto aumentou os teores de N, Ca, S, Na e resíduos minerais solúveis, bem como a condutividade elétrica, indicando sua mineralização. Em contrapartida, o cultivo diminuiu os teores totais de Fe e Pb, propiciando redução no risco de toxidez desses elementos. Para aplicação em solos agrícolas e áreas degradadas, o lodo de esgoto enquadra-se como da classe 2, atendendo completamente à norma vigente. Pelos baixos valores de C orgânico do lodo utilizado, a biomassa vegetal produzida pode ser incorporada ao lodo de esgoto para adequação e registro como fertilizante orgânico.

ABSTRACT The cultivation of grasses in sewage sludge (SS) with aeration improves the quality of this fertilizer, since the growth of the roots, the release of exudates and oxygenation, favor the mineralization of nutrients and the humification of organic matter. Thus, the present work aimed to evaluate the decomposition of SS using grass cultivation and aeration for use as organic fertilizer. The experiment was carried out in a randomized block design with four replications, in a 2 x 5 factorial scheme, corresponding to the presence or absence of culture with Pennisetum purpureum in SS, combined with five periods of aeration: 0, 14, 28, 42, and 60 days, with an air flow of 1,059 dm3.h−1.kg−1 of volatile solids. The analyses showed that the air injection in the SS did not influence the decomposition of organic matter and the cultivation of the grass in SS increased the levels of N, Ca, S, Na and soluble mineral residues, as well as the electrical conductivity, indicating its mineralization. On the other hand, cultivation decreased the total levels of Fe and Pb, providing a reduction in the risk of toxicity of these elements. For application in agricultural soils and degraded areas, the sewage sludge is classified as Class 2, completely complying with the current regulation. Due to the low organic C values of the sludge used, the vegetable biomass produced can be incorporated into it for suitability and registration as organic fertilizer.

RESUMO: Relatamos dois surtos de intoxicação por nitrato e nitrito na Paraíba, Nordeste do Brasil. O primeiro por Pennisetum purpureum (capim-elefante), e o segundo por P. purpureum e Brachiaria spp. (capim braquiária); ambos ocorreram durante uma estiagem prolongada. No primeiro surto, a irrigação das pastagens com água poluída e esgoto contribuiu para o acúmulo de nitrato. O segundo surto ocorreu em pastagens cultivadas na borda de uma barragem, que há muito tempo ficavam submersas, acumulando grande quantidade de matéria orgânica no solo. Outros prováveis fatores de risco para o acúmulo de nitrato incluíram o uso de fertilizantes químicos e herbicidas e a queima da vegetação. No primeiro surto, quatro bezerros de um total de 42 bovinos morreram, e no segundo surto 49 de 243 bovinos, incluindo adultos, jovens de um ano e um bezerro de 2 dias de idade morreram. Os sinais clínicos incluíram dispneia, cianose, ataxia e quedas, levando à morte. A presença de nitratos foi detectada em ambos os surtos pelo teste de difenilamina. Testes quantitativos foram realizados no segundo surto usando um medidor portátil de nitrato, e altas concentrações de nitrato foram encontradas. Os achados macroscópicos característicos e a ausência de lesões microscópicas e a resposta ao tratamento com azul de metileno foram fundamentais para o diagnóstico de intoxicação por nitratos e nitritos. Concluímos que a intoxicação por nitratos e nitritos em ruminantes na região semiárida do Nordeste do Brasil é frequente devido ao cultivo de gramíneas nas bordas de barragens que estiveram cobertas por água por longos períodos ou em áreas irrigadas por água poluída e/ou esgoto. Além disso, o uso de medidor portátil é uma alternativa eficaz para a quantificação de nitratos em pastagens.

ABSTRACT: We report two outbreaks of nitrate and nitrite poisoning in Paraíba, Northeast Brazil. The first, due to Pennisetum purpureum (elephant grass), and the second, due to P. purpureum and Brachiaria spp. (brachiaria grass), both occurred during a prolonged drought. In the first outbreak, the irrigation of the pastures with wastewater and sewage contributed to nitrate accumulation. The second outbreak occurred in pastures cultivated in the border of a dam, that had been submerged for long time accumulating large amounts of organic matter in the soil. Other probably risk factors for nitrate accumulation included the use of chemical fertilizers and herbicides and burning of the vegetation. In the first outbreak, four calves out of a total of 42 cattle died, and in the second outbreak 49 out of 243 cattle, including adults, yearlings, and a 2-day-old calf died. The clinical signs included dyspnea, cyanosis, ataxia, and falls, leading to death. The presence of nitrates was detected in both outbreaks using the diphenylamine test. Quantitative tests were performed in the second outbreak using a portable nitrate meter, and high nitrate concentrations were found. The characteristic macroscopic findings and absence of microscopic lesions and response to treatment with methylene blue were key to the diagnosis of poisoning by nitrates and nitrites. We conclude that poisoning by nitrates and nitrites in ruminants in the semiarid region of Northeastern Brazil is frequent due to the cultivation of grasses in the border of dams that had been covered by water for long periods or in areas irrigated by wastewater and/or sewage. In addition, the use of a portable measuring device is an effective alternative for the quantification of nitrates in pastures.

RESUMO As energias renováveis vêm ocupando cada vez mais espaço nas matrizes energéticas mundiais, e as biomassas lignocelulósicas são promissoras para essas fontes de energia. Objetivou-se desenvolver um modelo fuzzy para otimizar a concentração de sulfato ferroso e temperatura no pré-tratamento de capim-elefante. Foram utilizadas como entrada cinco concentrações (10; 15; 20; 25; e 30 mM) e três temperaturas (25; 40; e 55 ºC). A aplicação do modelo fuzzy evidenciou que os melhores resultados para a exposição à celulose (53,1 %) foram alcançados utilizando-se concentração de sulfato ferroso entre 20 e 22,5 mM e temperatura entre 39,5 e 42,5 ºC.

ABSTRACT Renewable energies have been occupying more and more space in energy matrices worldwide, and lignocellulosic biomasses are promising for these energy sources. This study aimed to develop a fuzzy model to optimize the ferrous sulfate concentration and temperature in the pre-treatment of elephant grass. Five concentrations (10, 15, 20, 25 and 30 mM) and three temperatures (25, 40 and 55 ºC) were used as input. The application of the fuzzy model evidenced that the best results for cellulose exposure (53.1 %) were achieved by using a ferrous sulfate concentration between 20 and 22.5 mM and temperature between 39.5 and 42.5 ºC.

ABSTRACT. The objective was to evaluate the morphometric, productive and chemical aspects of purple elephant grass as a function of nitrogen fertilization. The treatments consisted of applying 0, 20, 40, 60, and 80 kg ha-1 of N, using a randomized block design, with five treatments and four replications. The following were evaluated: plant height, number, length and leaf mass, stem diameter and mass, leaf/stem ratio, production of green and dry mass, support capacity for dairy cows, crude protein, neutral detergent fiber and mineral matter. The data were submitted to analysis of variance and Tukey's test at 5% probability. The increase in N doses did not affect (p < 0.05) the morphometry of the purple elephant grass, however it positively stimulated the productivity, the animal support capacity and the bromatological components of the harvested material. The lack of response to nitrogen fertilization may be related to the edaphocilimatic conditions during the experiment and efficiency in the use of N of the variety used. The results demonstrate the high demand of the cultivar for N, actively interfering in the forage yield.

ABSTRACT. This study investigated whether genotype influences the establishment of Pennisetum purpureum Schumach. The experimental design was a randomized complete blocks with four treatments and eight replications (n=8). The treatments were four genotypes of P. purpureum, two classified as tall sizes: P. purpureum cv. Elephant B and cv. IRI 381; and two as dwarf types: P. purpureum cv. Mott and Taiwan A-146 2.37. They were planted in a tropical wet and dry region of Brazil. Tall genotypes showed superior field sprouting rates (p < 0.05), ranging between 95-99%, while dwarfs varied between 88-90%, however, Elephant B and IRI 381 produced a much lower average number of tillers (31 and 32 linear m-1, respectively), than Taiwan A-146 2.37 and Mott (56 and 41 linear m-1, respectively) (p < 0.05). Dwarf genotypes produced lower biomass yields (p < 0.05), but this was genotype-dependent and did not impact on their establishment. The levels of non-structural carbohydrates (NSC) (>10%) in the planted stems were associated with satisfactory field sprouting of the elephantgrass genotypes. Despite some variations between the genotypes in terms of sprouting, tillering, and growth rates, the kind of genotype had no major significance on the establishment of the elephantgrass.

RESUMO: O objetivo deste estudo foi estimar a variação do teor de açúcar (°Brix) existente entre 95 acessos do banco ativo de germoplasma de capim-elefante da Embrapa Gado de Leite, localizado no campo experimental de Coronel Pacheco. Foram identificados os acessos com maior teor de açúcar, bem como avaliado o efeito da idade da planta sobre a variação da concentração de açúcar. O experimento foi conduzido em blocos ao acaso com duas repetições, 95 genótipos, duas idades de planta, 70 e 100 dias de crescimento, e análise do teor de açúcar em duas secções amostradas à 30 cm da base e na metade do colmo. A análise de variância considerou modelo de parcela subdividida no tempo, sendo os acessos, as parcelas e a idade da planta as subparcelas. As médias foram comparadas pelo teste de Scott Knott. Observou-se variação no teor de açúcar entre os acessos, porém não foi observado efeito significativo no teor de açúcar devido ao aumento da idade da planta. Entretanto, alguns acessos apresentaram interação significativa com aumento ou redução do teor de açúcar em decorrência do aumento da idade da planta. O acesso de maior média de teor de açúcares entre as duas idades foi BAG80, com 6,96%, e o de menor foi BAG13, com 4,03%.

ABSTRACT: The objective of this study was to estimate sugar content variation (°Brix) in 95 accessions from the elephant grass germplasm active bank of Embrapa Dairy Cattle research center, located in Coronel Pacheco, MG, Brazil. The accessions with the highest sugar content were identified, and the effect of plant age on sugar concentration was evaluated. The experiment was conducted in randomized blocks design with two replications. Sugar content analysis occurred twice during the growth-cycle (at 70 and 100 days) along two points of the stem, one 30 cm from the base and the other at the midpoint. The analysis of variance considered the split plot model, with accessions as main plots and plant age as subplots. The means were compared using the Scott Knott test. While there was sugar content variation between accessions, increased plant age had no significant effect on the sugar content. However, some accessions did have a significant increase or decrease in sugar content as they aged. The highest and lowest mean sugar content was 6.96% (in the accession BAG80) and 4.03% (in the accession BAG13) °Brix, respectively.

RESUMEN En épocas de escasez, los ganaderos recurren a conservar el alimento mediante procesos de fermentación anaeróbica, conocidos como ensilajes. Una vez que el silo es abierto, el sustrato resulta aeróbicamente estable, cuando, al momento de la apertura, conserva su integridad nutricional. Esto es el resultado de un ambiente ácido que restringe los efectos deletéreos de la acción de microrganismos patógenos, expresado en indicadores de estabilidad a la exposición aeróbica. Uno de los problemas empíricos que enfrenta el productor es resolver la pregunta de cómo evitar el deterioro del ensilaje, una vez es abierto, por lo cual, esta investigación apunta a la resistencia en el periodo de exposición aeróbica (PEA) de un ensilaje de Pennisetum purpureum (PP), con diferentes niveles de sustitución de Tithonia diversifolia (TD). El estudio, se adelantó en el Centro Internacional de Agricultura Tropical en Colombia. Con un ensilaje de 90 días de fermentación, se realizó una prueba de estabilidad aeróbica de siete días, usando ensilajes de un kilogramo, a diferentes proporciones (%) de TD/PP: 100/0, 67/33, 33/67 y 0/100, enriquecidos con dos aditivos basados en Lactobacillus. Se midió el cambio de la materia seca, temperatura y el pH, encontrándose una estabilidad a la exposición aeróbica. El papel de TD es notable, una vez que el ensilado entra en el PEA, debido a la capacidad tampón que amortigua el cambio de pH, una vez que se abre el silo, generando mayor estabilidad aeróbica.

ABSTRACT In times of scarcity, farmers resort to preserving food through anaerobic fermentation processes, known as silage. Once the silo is opened, the substrate is aerobically stable if it retains its nutritional integrity when opening. This is the result of an acidic environment that restricts the deleterious effects of the action of pathogenic microorganisms, expressed as indicators of stability to aerobic exposure. One of the empirical problems faced by the producer is to solve the question of how to avoid deterioration of the silage once it is opened, for which this research points to the resistance in the period of aerobic exposure (PEA) of a silage of Pennisetum purpureum (PP) with different levels of substitution of Tithonia diversifolia (TD). The study was conducted at the International Center for Tropical Agriculture in Colombia. With a 90-day fermentation silage, a seven-day aerobic stability test was carried out, using a kilogram silage at different proportions (%) of TD/PP: 100/0, 67/33, 33/67 and 0/100 enriched with two Lactobacillus-based additives. The change in dry matter, temperature and pH was measured, finding stability to aerobic exposure. The role of TD is remarkable once the silage enters the PEA due to the buffer capacity that buffers the change in pH once the silo is opened, generating greater aerobic stability.

ABSTRACT The cultivation of grasses in sewage sludge (SS) with aeration has the potential for stabilization of sludge organic matter in the production of organic fertilizer. Thus, the objective of this work was to evaluate the cultivation of Urochloa brizantha and Pennisetum purpureum under aerated system on the chemical and biological attributes of SS to obtain a matured organic fertilizer. The study was conducted in a randomized block design in a 2x2+2 factorial scheme with four replications. Factors consisted of cultivation of P. purpureum or U. brizantha in SS, with or without intermittent aeration. Control treatments were SS without cultivation, with or without aeration. Sewage sludge was collected in layers and the chemical and microbial attributes were evaluated. There was no significant difference between treatments for grass dry matter. The C/N ratio was not matched with organic fertilizer stabilization due to similar losses of C and N (~7%). However, microbial activity was reduced in the presence of plant cultivation demonstrating improvement in the properties of the organic fertilizer produced. Through uni- and multivariate analysis, organic fertilizer produced from SS aerated and cultivated with P. purpureum showed matured organic matter.

Abstract The present investigation was carried out to determine the extent of the incorporation of Tithonia diversifolia (TD) and the possibility of blending it with Pennisetum purpureum (PP) to obtain the maximum benefit for ensilability and for animal nutrition. Silage mixtures of wild sunflower (TD) and elephant grass (PP) were evaluated based on chemical composition, quantification of gas production, methane release and fermentation parameters. The silage blends were arranged in four T. diversifolia / P. purpureum proportions, namely: 100/0; 67/33; 33/67; and 0/100 (fresh weight). Silages with higher proportions of T. diversifolia increased crude protein content, in vitro digestibility while decreasing NDF and ADF fractions (P<0.05). High amounts of T. diversifolia showed the lowest gas production values (160.2 ml), while treatments with higher grass inclusion produced a greater amount of gas up to 194.5 ml. Methane production was higher by increasing the proportion of P. purpureum into the silage blends. The silage inoculum did not have any impact on in vitro gas production (P<0.05). Also, higher proportions of T. diversifolia reduced acidification process while P. purpureum inclusion facilitated lower pH values. Lactic acid bacteria inoculum tended to decrease pH of silages but no clear effects on silage temperature were observed. Silages with high proportions of T. diversifolia (67 % of inclusion) would be more palatable for animals and might also translate into larger animal performance due to greater protein supply and better digestibility than silages with larger proportion of P. purpureum (67 and 100 % of inclusion).

Resumen La presente investigación se llevó a cabo para determinar el grado de incorporación de Tithonia diversifolia (TD) y la posibilidad de mezclarla con Pennisetum purpureum (PP) para obtener el máximo beneficio para la ensilabilidad y para la nutrición animal. Las mezclas de ensilado de girasol silvestre (TD) y pasto elefante (PP) se evaluaron en función de la composición química, la cuantificación de la producción de gas, la liberación de metano y los parámetros de fermentación. Las mezclas de ensilado se organizaron en cuatro proporciones de T. diversifolia / P. purpureum, a saber: 100/0; 67/33; 33/67; y 0/100 (peso fresco). Los ensilados con mayores proporciones de T. diversifolia aumentaron el contenido de proteína cruda, la digestibilidad in vitro al tiempo que disminuyeron las fracciones de FDN y FDA (P<0.05). Las altas cantidades de T. diversifolia mostraron los valores de producción de gas más bajos (160.2 ml), mientras que los tratamientos con mayor incorporación de pasto produjeron una mayor cantidad de gas, hasta 194.5 ml. La producción de metano fue mayor al aumentar la proporción de P. purpureum en las mezclas de ensilado. El inóculo del ensilado no tuvo ningún impacto en la producción de gas in vitro (P<0.05). Además, las proporciones más altas de T. diversifolia redujeron el proceso de acidificación, mientras que la inclusión de P. purpureum facilitó valores de pH más bajos. El inóculo de bacterias ácido-lácticas tendió a disminuir el pH de los ensilados, pero no se observaron efectos claros sobre la temperatura del ensilado. Los ensilados con proporciones altas de T. diversifolia (67 % de incorporación) serían más apetecibles para los animales y también podrían traducirse en un mayor rendimiento animal debido a un mayor suministro de proteínas y una mejor digestibilidad que los ensilados con mayor proporción de P. purpureum (67 y 100 % de incorporación).

Resumen Se realizó un ensayo para evaluar el comportamiento productivo del pasto Cuba OM-22, en Santa Cruz, Guanacaste, localidad situada a 54 msnm, con una precipitación anual de 1834 mm. Se evaluó la producción de biomasa verde y seca, el contenido y la producción de proteína cruda por hectárea y el contenido de macronutrientes y micronutrientes del Cuba OM-22 sometido a cuatro dosis de nitrógeno, con cortes a los de 56 días: 50, 100, 150 y 200 kg N ha-1. El rendimiento de biomasa seca varió con las dosis de N aplicado, lo cual produjo 6,7 t, 8,5 t, 10,9 t y 11,3 t MS.ha-1 corte-1, la tasa de crecimiento de biomasa presentó valores de 120 kg, 152 kg, 195 kg y 201 kg MS ha-1 día-1, la producción de proteína cruda por hectárea fue de 459 kg, 751 kg, 1180 kg y 1459 kg PC ha-1 corte-1, con la aplicación de 50 kg, 100 kg, 150 kg y 200 kg N ha-1 corte-1 respectivamente. Todos los nutrientes se presentaron en cantidades adecuadas para la salud y producción animal, con la excepción del potasio (K), que mostró valores superiores a 3,0% de la materia seca, con las dosis de 150 y 200 kg N ha-1 corte-1. Se recomienda aplicar al pasto Cuba OM-22, 150 kg N ha-1 por corte de 56 días.

Abstract A study was conducted to evaluate the productive behavior of the Cuba OM-22 grass, in Santa Cruz, Guanacaste, county located at 54 masl, with a 1834 mm annual rainfall. Production of green and dry biomass, content and production of crude protein per hectare, and macro-nutrient and micro- nutrient content of Cuba OM-22 were evaluated, subjected to four doses of nitrogen, with cuts at 56 days; 50, 100, 150 y 200 kg N ha-1. The yield of dry biomass varied with the dosage of N applied, which produced 6.7 t, 8.5 t, 10.9 t and 11.3 t MS ha-1 cut-1, biomass growth rate presented values of 120 kg, 152 kg, 195 kg and 201 kg MS ha-1 day-1, production of crude protein per hectare was 459 kg, 751 kg, 1180 kg and 1459 kg PC ha-1 cut-1, with the application of 50 kg, 100 kg, 150 kg and 200 kg N ha-1 cut-1 respectively. All nutrients are presented in suitable animal health and production quantities, with the exception of potassium (K), which showed values greater than 3.0% of the dry matter, with the doses of 150 and 200 kg N ha-1 cut-1. It is recommended to apply 150 kg N ha-1 to Cuba OM-22 grass per cut of 56 days.

Resumo: O objetivo deste trabalho foi avaliar o valor nutritivo de silagens de genótipos anões e altos de capim-elefante (Pennisetum purpureum), consorciados ou não à cunhã (Clitoria ternatea). O experimento foi realizado em delineamento de blocos ao acaso, em arranjo fatorial 4x2 (quatro genótipos × dois sistemas de plantio). Os genótipos consorciados ou não à cunhã foram: IRI-381 e Elefante B, de porte alto; e Taiwan A-146 2.37 e Mott, anões. A forragem foi colhida após 60 dias de rebrota. Na silagem do capim Mott consorciado à cunhã, foram observados menores teores de lignina (78,1 g kg-1), fibra em detergente neutro (636,0 g kg-1) e proteína insolúvel em detergente neutro (13,15 g kg-1), além de maior recuperação da matéria seca (873,3 g kg-1). A silagem de Taiwan A-146 2.37 cultivado em consórcio com a leguminosa apresentou maior teor de proteína bruta (136,1 g kg-1). Em ambas as silagens, os teores de nitrogênio amoniacal foram bastante reduzidos (26,4 g kg-1). No entanto, maiores teores residuais de carboidratos solúveis em água foram observados nas silagens do consórcio (1,85 mg g-1) e do capim Mott em monocultivo (1,51 mg g-1). Além disso, houve menor digestibilidade in vitro da matéria seca (676,7 g kg-1) na silagem do consórcio. Os genótipos anões aumentam o valor nutricional da silagem de capim-elefante, comparados aos de porte alto. O consórcio com a cunhã melhora as características fermentativas da silagem, apesar de reduzir a sua digestibilidade. Portanto, a ensilagem do capim anão Mott consorciado à cunhã apresenta resultados mais promissores.

Abstract: The objective of this work was to evaluate the nutritional value of silages from tall-sized and dwarf elephant grass (Pennisetum purpureum) genotypes, intercropped or not with butterfly pea (Clitoria ternatea). The experiment was performed in randomized complete blocks, in a 4x2 factorial arrangement (four genotypes × two cropping systems). The genotypes intercropped or not with butterfly pea were: IRI-381 and Elephant B, tall sized; and Taiwan A-146 2.37 and Mott, dwarf. Forage was harvested 60 days after regrowth. In the silage from Mott grass intercropped with butterfly pea, lower contents of lignin (78.1 g kg-1), neutral detergent fiber (636.0 g kg-1), and neutral detergent insoluble protein (13.15 g kg-1), besides a greater dry matter recovery (873.3 g kg-1), were observed. The silage from Taiwan A-146 2.37 intercropped with the legume showed a greater crude protein content (136.1 g kg-1). In both silages, the ammonia nitrogen contents were quite reduced (26.4 g kg-1). However, greater residual water-soluble carbohydrate contents were observed in the silages from the intercrop (1.85 mg g-1) and from the Mott grass monocrop (1.51 mg g-1). Moreover, there was a lower in vitro dry matter digestibility (676.7 g kg-1) for the silage from the intercrop. Dwarf genotypes increase the nutritional value of elephant grass silage, compared with the tall-sized ones. Intercropping with butterfly pea improves silage fermentation characteristics, despite reducing its digestibility. Therefore, the ensilage of dwarf Mott elephant grass intercropped with butterfly pea shows more promising results.