Produção de biomassa e acúmulo de nutrientes pela vegetação espontânea em cultivo de café orgânico

To evaluate biomass production and nutrient accumulation by the spontaneous vegetation in organic coffee crops and the phytosociology of these species, an experiment was set up at Fazendinha Agroecológica, in Seropédica, Rio de Janeiro state, in Brazil. The experiment consisted of three treatments, corresponding to systems of cultivation of conilon coffee (Coffea canephora Pierre ex A. Froehner) in association with the tree legumes Gliricidia sepium (Jacq.) Kunth ex Walp. and Erythrina variegata L. (treatments 1 and 2), and a full sun cultivation system (treatment 3), distributed in a random block design with six replicates. Although six hoeings were performed over the course of one year, the aerial biomass produced by the spontaneous vegetation and the N, P, K, Ca, Mg and micronutrient contents accumulated in it were measured in only five periods4, to estimate the amount of nutrients that could be recycled after decomposition. The phytosociology of the spontaneous vegetation was evaluated in October 2006 and June 2007. Based on the species found, richness, abundance, relative frequency of species and Shannon’s diversity index were determined. The most significant biomass production values were obtained between October and December 2006, the highest results being found in coffee grown with gliricidia. No differences regarding the N, K, and Ca contents in the biomass were observed between the different treatments; however, the highest P content was registered in coffee grown in the full sun system, while the highest Mg content was found in coffee grown with gliricidia. The diversity of plant species is small and no differences can be observed among the systems. The most frequent invasive plant species in the systems, in both periods evaluated, were Commelina diffusa Burm. f. and Paspalum conjugatum L.Com o objetivo de avaliar a produção de biomassa e o acúmulo de nutrientes pela vegetação espontânea em cultivos orgânicos de café e a fitossociologia dessas espécies, foi desenvolvido um experimento na Fazendinha Agroecológica em Seropédica, RJ, onde foram avaliados três tratamentos, que corresponderam aos sistemas de cultivo de café Conilon (Coffea canephora Pierre ex A. Froehner) associado às leguminosas arbóreas Gliricidia sepium (Jacq.) Kunth ex Walp. e Erythrina variegata L. (tratamentos 1 e 3) e cultivado a pleno sol (tratamento 2), com oito anos de idade, os quais foram distribuídos no delineamento em blocos ao acaso com seis repetições. Apesar de terem sido realizadas seis roçadas durante o ano, em apenas cinco épocas, avaliaram a biomassa aérea produzida pela vegetação espontânea e os teores de N, P, K, Ca e Mg e micronutrientes acumulados na biomassa, com a finalidade de estimar a quantidade de nutrientes possíveis de serem reciclados após a decomposição. A fitossociologia da vegetação espontânea foi avaliada em outubro de 2006 e junho de 2007, e pelas espécies encontradas, determinaram a riqueza, a abundância, a frequência relativa das espécies e o índice de diversidade de Shannon. As produções mais significativas de biomassa foram obtidas no período de outubro a dezembro de 2006, registrando-se a maior produção no cultivo do café com glirícidia. Não há diferença entre os tratamentos quanto aos teores de N, K, Ca na biomassa; porém, o maior teor de P é observado no café a pleno sol, e o de Mg, no café com gliricídia. A diversidade de espécies vegetais é baixa e não há diferença entre os sistemas. As espécies de plantas invasoras encontradas em maior frequência nos sistemas nas duas épocas avaliadas são a Commelina diffusa Burm. f. (trapoeraba) e Paspalum conjugatum Berg. (Capim-forquilha)

Organic matter composition and paleoclimatic changes in tropical mountain peatlands currently under grasslands and forest clusters

Tropical peatlands are important ecosystems for Planet Earth, as they store large amounts of carbon and water. A better understanding of the impact of vegetation type and altitude in content, composition, and rate of accu mulation of organic matter is key for assessing the current role of such environments. This study evaluated fibric and soluble fractions as well as the lignocellulosic and the isotopic compositions of the peat organic matter from four tropical mountain peatlands located at different altitudes of the Serra do Espinhaço Meridional, state of Minas Gerais, Brazil. The peatlands are currently under grasslands and forest clusters. Samples of peat under both vegetation types were collected and analyzed for organic matter fractions, cellulose, and lignin (van Soest method), as well as carbon and nitrogen isotopes. Different depths were chosen for radiocarbon dating of se lected samples. The organic matter of peatlands currently under grasslands and forest clusters presented dif ferences in soluble fractions, lignocellulosic composition, and δ13C values. Multivariate analyses allowed grouping the peatlands by altitude and vegetation type. The chronological succession of grassland and forest clusters in tropical mountain peatlands was influenced by altitude and was related to paleoclimatic changes.info:eu-repo/semantics/publishedVersio

AVALIAÇÃO DA PRODUTIVIDADE DE CULTIVARES DE SOJA EM GARANHUNS-PE

A soja é uma oleaginosa muito estudada no Brasil, mas que ainda não há pesquisas consolidadas de adaptação para Pernambuco. O experimento teve como objetivo avaliar o desempenho e adaptação de cinco cultivares de soja no Agreste Meridional Pernambucano. Os tratamentos consistiram de cinco cultivares de soja: BRSMG 810C, BRSMG 752 S, BRS 326, BRS Sambaíba e BRS Tracajá, distribuídas em quatro blocos ao acaso. As características avaliadas foram: massa de 100 sementes, número de dias para o florescimento, números de dias para frutificação, acamamento, altura das plantas, número de nó por plantas, stand final, biomassa fresca da parte aérea, produtividade de vagem e produtividades de grãos. As cultivares BRS 326 e BRS SAMBAÍBA, por apresentarem sua alta produção de biomassa fresca são interessantes para a produção de forragem. A BRS MG 810C é a cultivar mais recomendada para plantio em Garanhuns-PE.

Antibacterial Activity from Momordica charantia L. Leaves and Flavones Enriched Phase

Momordica charantia L. (Cucurbitaceae) is a plant known in Brazil as “melão de São Caetano”, which has been related to many therapeutic applications in folk medicine. Herein, we describe antibacterial activities and related metabolites for an extract and fractions obtained from the leaves of that species. An ethanolic extract and its three fractions were used to perform in vitro antibacterial assays. In addition, liquid chromatography coupled to mass spectrometry and the molecular networking approach were used for the metabolite annotation process. Overall, 25 compounds were annotated in the ethanolic extract from M. charantia leaves, including flavones, terpenes, organic acids, and inositol pyrophosphate derivatives. The ethanolic extract exhibited low activity against Proteus mirabilis (MIC 312.5 µg·mL−1) and Klebsiella pneumoniae (MIC 625 µg·mL−1). The ethyl acetate phase showed interesting antibacterial activity (MIC 156.2 µg·mL−1) against Klebsiella pneumoniae, and it was well justified by the high content of glycosylated flavones. Therefore, based on the ethyl acetate phase antibacterial result, we suggest that M. charantia leaves could be considered as an alternative antibacterial source against K. pneumoniae and can serve as a pillar for future studies as well as pharmacological application against the bacteria