Porte da gramínea e inclusão da cunhã modificam o valor nutritivo da silagem de capim-elefante

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.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

Nutritional value, fermentation losses and aerobic stability of elephant grass (Pennisetum purpureum Schum.) silage treated with exogenous fibrolytic enzymes

The aim of this study was to evaluate nutritional value, fermentation losses, and aerobic stability of elephant grass silage (Pennisetum purpureum Schum.) treated with exogenous fibrolytic enzymes. The experiment was conducted in a completely randomized design with four replicates (experimental silos) and five levels of fibrolytic enzymes (0, 1.5, 3.0, 4.5 and 6.0%). For this, the elephant grass was ensiled at 70 days of age in plastic buckets with 20L capacity. Silos were opened 60 days after sealing. Analyses were made for chemical composition, in vitro dry matter digestibility (IVDMD), effluent losses (EL), gas losses (GL) and dry matter recovery (DMR), as well as the aerobic stability of the silage. Data were analyzed with PROC REG of SAS® University, at 5% probability. There was an increase in IVDMD content (p < 0.0001) and reduction in NDF and ADF contents (p < 0.0001) according to enzyme levels. These results were related to the increase in the degradation of fiber fractions. There were higher EL (p = 0.0062) as a function of enzyme levels and aerobic deterioration after silo opening, at all levels tested. Thus, it can be concluded that the exogenous fibrolytic enzymes change the chemical composition of elephant grass silage, and increase its digestibility and nutritional value. Moreover, when used alone as an additive, fibrolytic enzymes are not able to recover all dry matter of this silage (with effluent and gas losses), and are not able to maintain aerobic stability in the first hours after opening the silos

Fertilidade do solo, características produtivas e valor nutritivo de Urochloa decumbens (Stapf) R.D. Webster e Mimosa caesalpiniifolia Benth em monocultivo e sistema silvipastoril

Os sistemas silvipastoris desempenham papel importante na produção pecuária. A inserção de espécies leguminosas em áreas de pastagens de gramíneas tem potencial de aumentar a eficiência na utilização dos recursos naturais, podendo contribuir na melhoria do valor nutritivo da forragem produzida, além de melhoria nas condições químicas e biológicas do solo. O presente estudo buscou avaliar altura, massa de forragem, valor nutritivo do capim-braquiária [Urochloa decumbens (Stapf) R.D. Webster] e da sabiá (Mimosa caesalpiniifolia Benth.), composição botânica do pasto, densidade de forragem e relação folha:colmo da gramínea, proporção de solo descoberto, fertilidade do solo e presença de compostos secundários da leguminosa, em diferentes sistemas de exploração, épocas e anos de avaliação. A pesquisa foi realizada na Fazenda Experimental da Universidade Federal Rural de Pernambuco (UFRPE), localizada no município de Garanhuns-PE (8°58'52''S 36°27'47''W). Os tratamentos experimentais foram um sistema silvipastoril (SSP) de capim-braquiária com sabiá, além dos cultivos exclusivos de cada espécie, utilizando-se delineamento em blocos casualizados, com três repetições, ao longo dos anos de 2019 a 2021, em diferentes épocas (seca e chuvosa) de avaliação. A leguminosa foi cultivada em três fileiras duplas nas áreas de braquiária, espaçadas 2 m entre filas x 1 m entre plantas x 25 m entre fileiras, totalizando 600 plantas.ha-1. No cultivo exclusivo utilizou-se o mesmo espaçamento entre linhas e plantas, porém foi utilizado fileiras simples, totalizando assim 5.000 plantas.ha-1. Os sistemas de cultivo não afetaram a altura e a massa de forragem da gramínea, as variáveis sofreram efeito de época e ano de avaliação, bem como da interação desses fatores. A altura do dossel, as massas de forragem de colmo (MFC), de material verde (MFMV), de material senescente (MFS) e massa de forragem total (MFT) de U. decumbens variaram entre as épocas e anos. A altura foi superior na época chuvosa em ambos os anos (49,7 cm e 50,4 cm). A maior MFC foi obtida na época chuvosa do primeiro ano de avaliação (1431 kg MS.ha-1). A MFMV foi superior na época chuvosa em ambos os anos de avaliação, por outro lado MFS foi superior no primeiro ano na época seca e na época seca do segundo ano, com 4702 e 5101 kg MS.ha-1, respectivamente, tendo a MFT comportamento semelhante com MFS. A densidade de foragem foi superior na época chuvosa de 2019. A leguminosa desenvolveu-se mais em cultivo exclusivo (3,61 m), possuindo também maior massa de forragem nesse sistema (854 kg MS.ha-1), por outro lado, essa massa de forragem variou conforme ano e época. A composição botânica do pasto não foi afetada pelo sistema de cultivo, predominando a gramínea U. decumbens em todas as épocas e anos de avaliação. Os níveis de fertilidade do solo não sofreram influência do sistema de cultivo, sendo alterado com o passar dos anos. A maior relação folha:colmo foi obtida no primeiro ano de avaliação, atingindo uma relação de 1,13. Foi observado efeito da interação ano e época para o teor de PB da gramínea, destacando-se a época chuvosa de 2019 (71,76 g.kg-1) e a época seca de 2020 (73,87 g.kg-1). Não foi observado variação no teor de PB da forragem em relação aos sistemas de cultivo (P>0,05). Observou-se efeito isolado de época de avaliação para os teores de MS, EE e Celulose da gramínea, com maiores teores observados ao longo da época seca, sendo de 393,78 g.kg-1, 20,72 g kg-1 e 20,72 g.kg-1, respectivamente. Foi observado efeito da interação ano e época para os teores da fração MM e MO da gramínea, não diferindo entre anos na época chuvosa, variando a fração mineral de 62,24 g.kg-1 a 66,64 g.kg-1, enquanto que a MO foi maior época seca do ano de 2019 (951,58 g.kg-1). Observou-se efeito da interação ano e época para os teores médios dos carboidratos totais, obtendo-se maiores teores na época chuvosa de 2020 (871,70 g.kg-1) e na época seca no ano de 2019 (868,20 g.kg-1). Não foi observado efeito significativo para os teores de MS, MO, MM e Hemicelulose da leguminosa avaliada. O teor de PB da leguminosa diferiu entre a interação de anos e épocas, variando de 162,30 g.kg-1 na época chuvosa de 2019 a 88,44 g.kg-1 na época seca do mesmo ano. Em 2020, os resultados obtidos variaram de 149,21 g.kg-1 a 140,24 g.kg-1, não diferindo entre as épocas. A FDN não sofreu influência dos sistemas de cultivo, sendo significativa a interação entre ano x época, sendo superior na época chuvosa de 2019 (605,48 g.kg-1), em relação ao ano de 2020 e a época seca de 2019. A época seca de 2020 foi superior ao ano antecedente e a época chuvosa, possuindo 536,12 g.kg-1. O teor de FDA diferiu na interação ano x época de avaliação, com menor teor encontrado na época seca de 2019. Foi percebido elevada concentração de taninos condensados na leguminosa na época seca em comparação com a época chuvosa. O valor nutritivo da gramínea e da leguminosa em avaliação não é afetado quando utiliza-se estas espécies em consórcio, por outro lado, varia ao longo dos anos e épocas de avaliação, bem como os taninos condensado da leguminosa.Silvopastoral systems play an important role in livestock production. The use of forage legumes in areas of pastures has the potential to increase the efficiency in the use of resources, contribute to a better nutritional value of the forage and increase production, in addition, it improves the environmental and biological conditions of the soil. The present study aimed to evaluate the height, forage mass, forage density and leaf: stem ratio, the nutritional value of signal grass [Urochloa decumbens (Stapf) R.D. Webster] and sabiá (Mimosa caesalpiniifolia Benth.); botanical composition of the pasture, the proportion of uncovered soil, soil fertility and the presence of secondary components in the legume, in different evaluation systems, periods and years of evaluation. The research was carried out at the Experimental Farm of the Universidade Federal Rural de Pernambuco (UFRPE), located in the municipality of Garanhuns-PE (8°58'52''S 36°27'47''W). The experimental treatments were a silvopastoral system (SSP) of signal grass with sabiá, in addition to monocropping systems of each species, using a randomized block design, with three replications. The experiment was carried out for two years (2019 to 2021), at different seasons (dry and rainy). The legume was grown in three double rows in the signal grass pastures, spaced 2m between double rows, 1m between plants and 25 m between each set of double rows, totaling 600 plants.ha-1. In the monocropping systems cultivation, the same spacing between rows and plants was used, however, single rows were used, totaling 5,000 plants.ha-1. The cropping systems did not affect the height and forage mass of the grass, the variables were affected by the season and year of evaluation, as well as the interaction of these factors. Canopy height, stem forage mass (SFM), green forage mass (GFM), senescent material (SM) and total forage mass (TFM) of signal grass varied between seasons and years. The height of the signal grass was higher in the rainy season in both years (49.7 cm and 50.4 cm). The greater SFM was obtained in the rainy season of the first year of evaluation (1431 kg DM.ha-1). GFM was greater in the rainy season in both years of evaluation, on the other hand, SM was greater in the first year in the rainy season and the dry season of the second year 4702 and 5101 kg DM.ha-1, respectively, with TFM having similar behavior. The forage density was superior in the rainy season of 2019. The legume tree developed more under monocropping cultivation (3.61 m), also having a greater forage mass in this system (854 kg DM.ha-1), on the other hand, this forage mass varied according to year and season. The botanical composition of the pasture was not affected by the cultivation system, predominating the signal grass in all seasons and years of evaluation. Soil fertility levels were not influenced by the cropping system, being changed over the years. The greatest leaf: stem ratio was obtained in the first year of evaluation, reaching a ratio of 1.13. An interaction effect of the year and season was observed for the crude protein (CP) content of the grass, especially in the rainy season of 2019 (71.76 g.kg-1) and the dry season of 2020 (73.87 g.kg-1). No variation was observed in the crude protein content of the forage concerning cropping systems (P>0.05). An isolated effect of the evaluation period was observed for the contents of dry matter, ethereal extract (EE) and cellulose of the grass, with the greatest levels observed throughout the dry season 393.78 g.kg-1, 20.72 g kg-1 and 20.72 g.kg-1, respectively. An interaction effect of the year and season was observed for the contents of the mineral and organic matter fractions of the grass, not differing between years in the rainy season. The mineral fraction varied from 62.24 g.kg-1 to 66.64 g.kg-1, while the organic matter was the greater in the dry season of 2019 (951.58 g.kg-1). An interaction effect between the year and season was observed for the average levels of total carbohydrates, with greater levels in the rainy season of 2020 (871.70 g.kg-1) and in the dry season in the year 2019 (868.20 g.kg -1). No significant effect was observed for the contents of dry matter, organic matter, mineral matter and hemicellulose of the legume evaluated. The crude protein content of the legume differed between the interaction of years and seasons, ranging from 162.30 g.kg-1 in the rainy season of 2019 to 88.44 g.kg-1 in the dry season of the same year. In 2020, the results obtained ranged from 149.21 g.kg-1 to 140.24 g.kg-1, not differing between seasons. The NDF was not influenced by cropping systems, the interaction between year x season being significant, with greater NDF contents in the rainy season of 2019 (605.48 g.kg-1) compared to the year 2020 and the dry season of 2019. The dry season of 2020 was superior to the previous year and the rainy season, with an NDF of 536.12 g.kg-1. The ADF content differed in the interaction between year and season, with a lower content found in the dry season of 2019. A high concentration of condensed tannins was observed in the legume during the dry season compared to the rainy season. The nutritive value of the grass and the legume under evaluation was not affected when these species are used in the consortium, on the other hand, it varies over the years and evaluation periods, as well as the condensed tannins of the legume.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPE

DYNAMICS OF HERBACEOUS VEGETATION IN CAATINGA MANIPULATED WITH GRAZING EXCLUSION UNDER PHOSPHATE FERTILIZATION

The semi-arid region accounts for about 70% of the surface area of the Brazilian northeast, and the most important forage resource is the Caatinga, covering approximately 54% of this region. However, about 40% of this vegetation is in secondary succession. The areas in the process of degradation range from low to severe intensity, and total more than 20 million hectares, reflecting the intense use of the land, such as the overgrazing. The objective of this study was to evaluate the influence of different doses of phosphorus (0, 50 and 100 kg P2O5 ha-1 year-1) on the dynamics of herbaceous vegetation at different times of the year, in a Caatinga area manipulated without grazing for four years. The experiment was conducted at the Serra Talhada-UFRPE Academic Unit during the years 2015 and 2016. We used a randomised block design with three blocks and four replicates per block. Phosphate fertilisation in grazing exclusion areas promoted an increase in forage mass of the enriched Caatinga herbaceous stratum at all evaluation times, especially in the dry season of 2016, which showed values above the average of 7950 kg DM ha-1. In addition, it promoted an increase in the participation of buffelgrass in the floristic composition, increasing its involvement in the area to around 74% at the maximum dose of phosphorus used. Thus, phosphate fertilisation at up to 100 kg of P2O5 ha-1 year-1, together with grazing exclusion, can help to recover the Caatinga enriched with buffelgrass and optimise its use by reducing the formation of new grazing areas in the Caatinga