Evaluation of silages of sweet potato vine

O presente trabalho teve como objetivo selecionar clones de batata-doce com potencial para uso na alimenta??o animal. O experimento foi conduzido em blocos ao acaso, com 11 clones e quatro repeti??es. Os clones avaliados fazem parte do banco de germoplasma da Universidade Federal dos Vales do Jequitinhonha e Mucuri, sendo: BD-06, BD-25, BD-15, BD-38, Cambraia, BD-31-TO, BD-67, BD-45, BD-42, BD-54 e a cultivar Brazl?ndia Rosada. Nas ramas coletadas do experimento foram avaliados o teor de mat?ria seca e as produtividades de massa verde e massa seca. Nas silagens de ramas foram avaliados o pH e os teores de mat?ria seca (MS), prote?na bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ?cido (FDA), nutrientes digest?veis totais (NDT), f?sforo, c?lcio e s?dio. N?o houve diferen?a significativa para a produtividade de massa verde e de massa seca das ramas entre os clones de batata-doce. As silagens produzidas caracterizam-se como volumosos de boa qualidade, apresentando teores satisfat?rios de prote?na bruta (11,59%), FDN (31,98 a 39,68%), FDA (29,65 a 35,45%) e NDT (62,90 a 66,91%), comprovando o potencial de utiliza??o das ramas da batata-doce na forma de silagem.Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Empresa de Pesquisa Agropecu?ria de Minas Gerais (EPAMIG)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)The objective of this study was to select potential clones of sweet potato for animal feeding purposes. The experiment was carried out in a randomized block design with four replications. Eleven clones BD-06, BD-25, BD-15, BD-38, Cambraia, BD-31-TO, BD-67, BD-45, BD-42, BD-54 and the cultivar Brazl?ndia Rosada belonging to germplasm bank of the Federal University of Vales do Jequitinhonha and Mucuri (UFVJM) were evaluated. We estimated the dry matter content and the productivity of green and dry mass of the vine. The traits pH, dry matter, crude protein phosphorus, calcium and sodium were estimated in the evaluation of silages quality. There was no significant difference in productivity of green mass and dry mass among the clones of sweet potato. The obtained silages had sufficient levels of crude protein (11.59%), neutral detergent fiber (31.98 to 39.68%), acid detergent fiber (29.65 to 35.45%) and total digestible nutrients (62.90 to 66.91%) proving the potential use of the sweet potato vine as silage in animal feeding

Lignocellulosic and isotopic composition of vegetation and soil organic matter of a tropical peat: I floristic composition, biomass and carbon stock

A mat?ria org?nica do solo (MOS) ? um dos grandes reservat?rios de carbono (C) da Terra e constitui um dos principais componentes do ciclo do C. Turfeiras, ambientes acumuladores de MOS, s?o produto da decomposi??o de vegetais, que se desenvolvem e se acumulam em ambientes saturados com ?gua, sendo o est?dio inicial da sequ?ncia de carbonifica??o. A fitomassa participa de forma marcante no ciclo global do C, armazenando em torno de 85 % de todo o C terrestre acima do solo. O tecido vegetal ? composto principalmente por lignina, celulose e hemicelulose, constituindo at? 85 % da biomassa seca. As plantas discriminam C de forma diferenciada, em raz?o de seu ciclo fotossint?tico (C3, C4 e CAM). As turfeiras da Serra do Espinha?o Meridional (SdEM-MG) s?o colonizadas por vegeta??o de Campo Limpo ?mido (CLU) e de Floresta Estacional Semidecidual (FES), onde ocorrem esp?cies dos ciclos fotossint?ticos C3 e C4. Este trabalho objetivou avaliar a contribui??o dessas duas fitofisionomias para o ac?mulo de MOS, por meio da avalia??o da fitomassa e da composi??o lignocelul?sica e isot?pica da vegeta??o e da MOS. A turfeira estudada localiza-se na SdEM e ocupa 81,75 ha. Para a estimativa da fitomassa do CLU e da FES, foram marcadas tr?s parcelas de 0,5 x 0,5 m em cada fitofisionomia, onde todos os indiv?duos da parcela foram cortados e armazenados. Para as an?lises isot?picas e lignocelul?sicas da vegeta??o, identificaram-se as esp?cies dominantes em cada fitofisionomia. Amostras de solo foram coletadas em tr?s locais representativos sob cada fitofisionomia, a cada 5 cm de profundidade, at? 50 cm. Foram extra?das a celulose e a lignina das folhas das 15 esp?cies dominantes e das 60 amostras de turfeira para quantifica??o e determina??o dos valores de ?13C and ?15N. Para data??o da MOS, o 14C foi determinado em tr?s profundidades, sob o CLU e a FES. A produ??o da fitomassa da FES foi muito superior ? produ??o da do CLU. Os sinais isot?picos e a composi??o lignocelul?sica da vegeta??o e da mat?ria org?nica do solo evidenciaram que a turfeira foi formada pela deposi??o de mat?ria org?nica da vegeta??o que a coloniza. O crescimento vertical e a taxa de ac?mulo de C foram muito mais elevados sob a FES do que sob o CLU.Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Empresa de Pesquisa Agropecu?ria de Minas Gerais (EPAMIG)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Soil organic matter (SOM) is one of the major reservoirs of carbon on Earth and is one of the key contributors to the carbon cycle. Peatlands are natural accumulators of organic matter commonly derived from decomposing plant residues in water-saturated environments, and represent an initial stage of a much longer pedogenic pathway leading to carbonification. The soil biomass markedly influences the global carbon cycle, accounting for approximately 85 % of all carbon on the Earth's surface. Plant tissues are mainly composed of lignin, cellulose and hemicelluloses, representing as much as 85 % of their dry biomass. Plants usually discriminate carbon differentially, according to their photosynthetic cycle (C3, C4 and CAM). The vegetation of the bogs in the southern domain of Serra do Espinha?o (SdEM; Brazil) consists mostly of moist grassland (CLU) and semideciduous forest (FES), with species of both C3 and C4 cycles. This study was designed to discriminate the contribution of these two vegetation types to the accumulation of soil organic matter by an analysis of the biomass and of the lignocellulosic and carbon isotopic composition and SOM. The studied peat is located in SdEM and covers an area of 81.75ha. Three 0.5x0.5m plots were marked per vegetation type, to delimit the sampling areas, for which biomass of CLU and FES were estimated. All plants per plot were cut and adequately stored to preserve as much of their fresh characteristics as possible. To characterize the isotopic and lignocellulosic composition of the vegetation, the species of each vegetation type were systematically identified according to their main botanic characteristics. Soil samples were collected at three representative sites under each vegetation type, at intervals of 5 cm, down to a depth of 50 cm. Cellulose and lignin were extracted from leaves of 15 dominant species and 60 peat samples, to quantify and determine the values of ?13C and ?15N. The 14C was determined at three depths under CLU and FES. The biomass production under FES was much higher than the biomass production under CLU. The isotopic signals and lignocellulosic composition of the vegetation and SOM confirmed that this peat was originated by the deposition of organic matter from the colonizing vegetation. The vertical growth and the carbon storage rates are much higher under FES than under CLU

Lignocellulosic and isotopic composition of vegetation and soil organic matter of a tropical peat: II humic substances and humification processes

Grande parte da mat?ria org?nica de Organossolos das turfeiras ? composta por subst?ncias h?micas, formadas pela transforma??o de res?duos org?nicos pelos microrganismos do solo e pela polimeriza??o dos compostos org?nicos em macromol?culas resistentes ? degrada??o biol?gica. Os processos de humifica??o da mat?ria org?nica do solo (MOS) ainda s?o pouco compreendidos e o conhecimento sobre os precursores das subst?ncias h?micas ? limitado, sendo apresentadas rotas diferentes para a forma??o dessas subst?ncias. Contudo, em todas as rotas, destaca-se a participa??o da lignina. Is?topos est?veis (13C, 15N) podem ser utilizados para rastrear processos de humifica??o da MOS, por meio da identifica??o de seus precursores. Este trabalho teve como objetivo avaliar comparativamente a composi??o isot?pica da vegeta??o das fitofisionomias que colonizam uma turfeira tropical de altitude composta de Campo Limpo ?mido (CLU) e de Floresta Estacional Semidecidual (FES), em rela??o ? composi??o isot?pica das subst?ncias h?micas da MOS. A turfeira estudada ocupa 81,75 ha. Para as an?lises isot?picas e lignocelul?sicas da vegeta??o, foram identificadas as esp?cies dominantes em cada fitofisionomia. Amostras de solo foram coletadas em tr?s locais representativos sob cada fitofisionomia, a cada 5 cm de profundidade, at? 50 cm. As subst?ncias h?micas dessas amostras foram fracionadas, assim como calculados os valores de ?13C e ?15N nas fra??es h?micas, respectivamente a partir da determina??o dos is?topos est?veis 12C e 13C e 14N e 15N. Os teores de lignina e seus valores de ?13C s?o mais elevados na vegeta??o e MOS sob FES em rela??o ? vegeta??o e MOS sob CLU. Os teores de humina s?o mais elevados entre as subst?ncias h?micas na MOS, sob as duas fitofisionomias; os de ?cidos h?micos s?o mais elevados na MOS sob CLU, em rela??o ? FES; e os de ?cidos f?lvicos s?o mais elevados na MOS sob a FES, em rela??o ao CLU. O ?13C da lignina apresenta similaridade elevada em rela??o ao ?13C da humina, dos ?cidos h?micos e dos ?cidos f?lvicos. As varia??es na composi??o lignocelul?sica das esp?cies que colonizam o CLU e a FES promovem diferen?as nas taxas e nos produtos da humifica??o da MOS.Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG)Empresa de Pesquisa Agropecu?ria de Minas Gerais (EPAMIG)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Much of the organic matter of a typical peat consists of humic substances, mainly formed via humification of organic residues, decomposed by soil microorganisms, and by the polymerization of organic compounds to functional macromolecules, which are normally more resistant to degradation. The fundamental pathways governing the humification of soil organic matter (SOM) are not well understood so far, and most available data about the identified chemical precursors of humic substances and the main chemical routes by which they are transformed in the peat environment are still poorly understood. What is clear is that all routes involve lignin as a chemical intermediate. Stable isotopes ( ?13C, ?15N) can be used to trace humification processes of the soil organic matter (SOM), by identifying their precursors. The purpose of this study was to compare the isotopic composition of vegetation materials from the two bog vegetation types that colonize a tropical highland peatland: moist grassland (CLU) and semideciduous forest (FES), based on the isotopic composition of humic substances of SOM. The whole area of the studied peatland occupies 81.75 ha. To identify the isotopic and lignocellulosic vegetation composition, materials of the dominant species of each vegetation type were sampled. Soil samples were collected from three representative sites per vegetation type, at intervals of 5 cm from the surface down to a depth of 50 cm. The humic substances were isolated from these samples; signals of ?13C and ?15N were determined for the humic fractions. The lignin and and ?13C values were higher in vegetation and SOM under FES than in SOM under CLU. Humin contents were high in SOM under both vegetation types; the levels of humic acids were higher in SOM under CLU than in FES; fulvic acid contents were higher in SOM under FES than CLU. The 13C values for lignin were highly similar to those for humic acids and fulvic acids. Variations in the lignocellulosic composition of the species that colonize the CLU and FES promote different rates and SOM humification products