Sebastião Manhães Souto

Capim tanzânia (Panicum maximum) sob sombreamento e manejo de corte

Successful silvopastoral systems depend, among other factors, on identifying of grasses tolerant to shading, and knowledge of the pasture management to which they will be submitted. The literature reports separate results on grass, sometimes about the effect of shading and sometimes about the effect of cutting height and interval. The objective of the present research was to study the performance of Panicum maximum cv. Tanzânia, under four shading levels (0, 25, 50 and 75%), two intervals (30 and 60 days) and three cutting heights (15, 25 and 35 cm). A randomized block design in splitplots with three replications was used, the shading levels representing the units and the factorial the cutting intervals and heights, representing subunits. The results of the treatment effects on the variables showed that the treatments in the with greater cutting interval and heights and the lower shading levels provided to more canopy dry matter in the plants, while the greatest interval and shading levels resulted in the biggest values registered for leaf area.

Fixação biológica de nitrogênio em pastagens com diferentes intensidades de corte

Arch. Zootec. 59: 21-30. 2010. Descargas 832 FIXAcaO BIOLoGICA DE NITROGeNIO EM PASTAGENS COM DIFERENTES INTENSIDADES DE CORTE* BIOLOGICAL NITROGEN FIXATION IN GRASSLAND WITH DIFFERENT CUTTING INTENSITIES Silva, L.L.G.G.1, Alves, G.C.2A, Ribeiro, J.R.A.2B, Urquiaga, S.2C, Souto, S.M.2D, Figueiredo, M.V.B.3 e Burity, H.A.4 1UFRRJ. Coordenacao da Area Verde. IPJBRJ. Rua Jardim Botânico, 1008. CEP 22470180. Rio de Janeiro RJ. llggalindo@yahoo.com.br 2UFRRJ. Embrapa. Agrobiologia. BR 465, km 47. CEP 23851970. Seropedica RJ. Brasil. Agabrielacalves@yahoo.com.br; Bjabetous@yahoo.com.br; Csegundo@cnpabembrapa.br; Dsmsoouto@cnpab.embrapa.br 3EPEAL. IPA. CP 699. CEP 57025050. Maceio, AL. Brasil. mbarreto@elogica.com.br 4Embrapa. IPA. CP 1022. CEP50761000. Recife, PE. Brasil. burity@ipa.br Palavras chave adicionais Brachiaria. Capim elefante. Bacterias diazo-troficas. Additional keywords Brachiaria. Elephant grass. Diazotrophic bacteria. Resumo O manejo correto numa pastagem e o uso da fixacao biologica de nitrogenio (FBN) ajudam a torna-la sustentavel. Foram realizados tres experimentos, cada um com uma especie de capim forrageiro na estacao experimental da Empresa Pernambucana de Pesquisa Agropecuaria em Itambe, na Zona da Mata de Pernambuco. Foram avaliadas a producao de materia seca, acumulo de nitrogenio e FBN das plantas sob varios regimes de corte. O delineamento experimental foi inteiramente casualizado com 5 repeticoes que foram usasadas. Para Brachiaria decumbens e B. humidicola foram usadas intensidades de corte 5, 15, 25 cm e 25 cm + 80 kg N ha-1, e para o Pennisetum purpureum, 5, 25, 50 cm e 50 cm + 80 kg N ha-1. Os periodos avaliados foram transicao seca/aguas e aguas em 2001. A FBN foi estimada pela abundância natural (d15N). Corte drastico (5 cm), no periodo de transicao seca/aguas, contribuiu para producao e acumulo de nitrogenio na B. decumbens, mas nao houve influencia significativa das intensidades de cortes na FBN nas tres pastagens e nas estacoes. Concluiu-se que a contribuicao da FBN variou com a estacao e que cortes altos nao teve influencia sobre o N acumulado, deste modo confirma-se que as tres gramineas sao tolerantes a cortes drasticos. Summary The correct management of pastures and the use of biological nitrogen fixation (BNF) therein should be sustainable. As part of an investigation into how best to use BNF in pastures three experiments were performed at the experimental station of Empresa Pernambucana de Pesquisa Agropecuaria, Itambe, Pernambuco. These experiments evaluated the production of dry matter and N accumulation and BNF under various cutting regimes. A random experimental design with 5 replications was used. For Brachiaria decumbens and B. humidicola the treatments consisted of cutting intensities of 5, 15 and 25 cm, and 25 cm + 80 kg N ha-1, and for Pennisetum purpureum cutting intensities 5, 25 and 50 cm and 50 cm + 80 kg N ha-1. The periods in which the pastures were evaluated were the transition of the dry/wet season and the wet season of 2001. Accumulation of N via BNF was estimated by the natural abundance (d15N) method. Drastic cutting (5 cm) in the dry/wet season transition resulted in high accumulation of dry matter and N in B. decumbens, but there was no effect of cutting intensity on BNF by any of the grasses in either of the seasons. The conclusion is that the BNF contribution varied with season, and that high cutting did not have any influence on N accumulation, thus confirming that the three pasture grasses are tolerant to drastic cutting.

Leguminosas arbóreas introduzidas em pastagem

The objective of this work was to analyse, by means of multivariate variance analysis, the behaviour of 16 leguminous tree species introduced into pastures of Brachiaria decumbens from unprotected young plants and under grazing, in four periods of the year, in Seropedica, RJ, Brazil. Nine variables, related to length and to number of sprouting, before and after animal grazing, were used for the evaluation. The statistical difference of the means of the principal canonical variable, calculated by the Scott-Knott test, indicated the formation of four groups, and the Mimosa tenuiflora group stood out at the 3 rd and 4 th evaluations. Difference among treatment means for each variable, calculated by Bonferroni confidence intervals, showed that the greatest sprouting length and the highest number of sprouting, after grazing, were found in M. tenuiflora. This leguminous species is indicated to be introduced into B. decumbens pasture of the region, with higher probability of success, without protection of the young plants and under grazing.

Mudas de leguminosas arbóreas introduzidas em pastagem de Tifton-85 com animais

EnglishThe introduction of unprotected young plants of 16 leguminous tree species into bermuda grass cv. Tifton-85 pastures under grazing was evaluated in four different moments of the year at the Seropedica Municipality, RJ. Nine variables related to length and number of sproutings were used for the evaluations before and after animal grazing. Difference among treatments means for each variable, calculated by Bonferroni confidence intervals, revealed that jurema preta (Mimosa tenuiflora) presented the difference smallest on length and number of sproutings after grazing. The results confirm the recommendation of jurema preta as the tree legume with the highest chances of successful growth for studied region, always the introduction into the pastures is to be made without grazing protection. portuguesEm pastagem de capim bermuda cv. Tifton-85 foi avaliado o desempenho de mudas de 16 especies de leguminosas arboreas, sem protecao e na presenca de animais, em tres epocas diferentes do ano, no municipio de Seropedica-RJ. Foram selecionadas nove variaveis relacionadas ao comprimento e numero de brotos das mudas, antes e apos o pastejo com 30 novilhas mesticas leiteiras. Diferencas entre as medias dos tratamentos para cada variavel, foram calculadas por meio de intervalos de confianca de Bonferroni, mostraram que jurema preta (Mimosa tenuiflora) apresentou a menor diferenca no comprimento e numero de brotos apos o pastejo. Os resultados relacionados as variaveis apos o pastejo para a jurema preta confirmam a sua recomendacao para a regiao, como a leguminosa arborea com maior probabilidade de sucesso, para introducao na pastagem, sem a protecao das mudas e na presenca do gado.