Discriminant analysis of soils under different land uses in the Atlantic Rain Forest area using organic matter attributes

Na região serrana do Estado do Rio de Janeiro (bioma Mata Atlântica), pequenos agricultores praticam agricultura itinerante no sistema de corte e queima. Neste trabalho, amostras de horizontes superficiais (0 -15 cm) de um Latossolo Vermelho-Amarelo sob cinco diferentes coberturas vegetais (Mata Atlântica, cultivo anual, café, banana e pastagem) foram coletadas para caracterização química dos teores de carbono nas diferentes frações de substâncias húmicas. As amostras obtidas sob mata e sob pastagem puderam ser nitidamente isoladas das demais pelo modelo discriminante construído. Aquelas representativas do grupo das culturas (banana, café e cultivo) foram superposicionadas, indicando haver semelhança entre os atributos relativos à matéria orgânica nos solos sob esses usos. O modelo obtido permitiu classificar corretamente 88% das amostras analisadas. Os atributos ácidos fúlvicos (AF), carbono orgânico (C), nitrogênio total (N) e relação C/N foram selecionados pelo modelo, sendo o teor de ácidos fúlvicos o atributo de maior peso relativo. Esse resultado indica que o fracionamento de substâncias húmicas permite a observação de alterações no solo que não são possíveis de serem identificadas pela simples determinação do teor de carbono orgânico total. Pelo padrão de agrupamento das áreas (mata-pastagem e banana-café-cultivo), denotou-se que o uso de fertilizantes pode se relacionar com alterações em atributos indicadores importantes, como o teor de ácidos fúlvicos.In the mountain region of the State of Rio de Janeiro (Atlantic Rain Forest biome), small farmers practice shifting cultivation in the slash and burn system. In this work, soil surfaces samples (0-15cm) of a Yellow Red Latossolo under five different vegetal coverings (Atlantic Rain Forest, annual culture, coffee, banana and pasture), had been taken in the small farming area of Bom Jardim RJ for soil chemical characterization and carbon content analysis in the different humic fractions. The samples taken under forest and pasture could be clearly isolated from the other groups for the discriminante model created. For the banana, coffee and culture groups, a certain overlapping was observed, indicating a similarity of the soil organic matter attributes between these coverings. The model allowed to correctly classify 88% of the analyzed samples. The fulvic acid (AF), organic carbon (C), total nitrogen (N), and the C/N ratio had been selected by the model, with the fulvic acids having the attribute of higher relative weight. This result suggests that the humic acids fractionation allows the detection of alterations in the soil that are not possible to be identified for the simple determination of the total organic carbon. The discriminate pattern of areas (forest-pasture and banana-coffe-culture) denotes that fertilizer could be related with changes in some important indicator attributes such as fulvic acids.(FAPERJ) Fundacao de Amparo a Pesquisa do Estado do Rio de JaneiroBanco MundialCNPq - PRONE

Corrigendum to "A framework proposal for sustainability assessment of sugarcane in Brazil"

In many countries the biofuel sector was encouraged to expand its activities, supported by public policies incentives, with the main aims to improve energy security and to reduce greenhouse gas (GHG) emissions. The Brazilian government followed these initiatives and undertook its responsibilities considering the international consensus related to the need to mitigate climate change. One of the theses commitments concerned actions to reduce the GHG emissions by 37% in 2020. The Sugarcane Agroecology Zoning provides technical support to policy makers in order to direct sugarcane expansion to permitted areas. It is considered a guideline to achieve sustainable sugarcane production in Brazil. However, although the zoning aimed at sustainable production, it only considered natural aspects of the country, as soils and climate. Currently an approach that considers all three dimensions of sustainability (environmental, economic, social) is still missing. This paper proposes a framework to evaluate biofuel sustainability to support public policies, especially concerning improvements in Brazilian decision-support tools

A framework proposal for sustainability assessment of sugarcane in Brazil

In many countries, the biofuels sector was encouraged to expand its activities supported by public policies incentives, especially to achieve improvements in energy security and to reduce greenhouse gas (GHG) emission. The Brazilian government followed these initiatives and undertook some responsibilities against the international scenario related to climate change. One of the theses commitments concerning actions to reduce the GEE emissions by some 37% by 2020. The Sugarcane Agroecology Zoning provides technical subside to policy makers to direct sugarcane expansion to permitted areas and a sustainable production in Brazil and is considered a guideline to sustainable sugarcane production in Brazil. However, although aiming at a sustainable production, the zoning only considered natural aspects of the country, as soils and climate and an approach that consider all the dimensions of the sustainability is still missing. Hence, this paper aims to propose a framework to evaluate biofuel sustainability to support public policies, especially concerning improvements in Brazilian decision-supporting tools

Regional scale land use/land cover classification using temporal series of MODIS data at the High Taquari Basin, MS, Brazil

International audienceThis paper describes a methodology for providing systematic land use/land cover classification on a regional scale, with specific application to the High Taquari Basin, in the state of Mato Grosso do Sul, Brazil. The methodology is based on previous work developed at INRIA by Bouzidi et al. (2000) and proposes the use of multitemporal 250m resolution surface reflectance data from the Moderate Resolution Imaging Spectroradiometer (MODIS), on board NASA's Terra satellite. This data will be coupled with higher-resolution training information in order to compute characteristic temporal MODIS reflectance profiles for each class and each band. A linear mixture model will then be applied so as to compute the proportions of each class within each MODIS pixel over areas where classification information may not be available, thus enabling the monitoring of land use/land cover over large regions such as the High Taquari Basin and its adjacencies

Mutation dynamics of CpG dinucleotides during a recent event of vertebrate diversification

<p>DNA methylation in CpGs dinucleotides is associated with high mutability and disappearance of CpG sites during evolution. Although the high mutability of CpGs is thought to be relevant for vertebrate evolution, very little is known on the role of CpG-related mutations in the genomic diversification of vertebrates. Our study analysed genetic differences in chickens, between Red Junglefowl (RJF; the living closest relative to the ancestor of domesticated chickens) and domesticated breeds, to identify genomic dynamics that have occurred during the process of their domestication, focusing particularly on CpG-related mutations. Single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) between RJF and these domesticated breeds were assessed in a reduced fraction of their genome. Additionally, DNA methylation in the same fraction of the genome was measured in the sperm of RJF individuals to identify possible correlations with the mutations found between RJF and the domesticated breeds. Our study shows that although the vast majority of CpG-related mutations found relate to CNVs, CpGs disproportionally associate to SNPs in comparison to CNVs, where they are indeed substantially under-represented. Moreover, CpGs seem to be hotspots of mutations related to speciation. We suggest that, on the one hand, CpG-related mutations in CNV regions would promote genomic ‘flexibility’ in evolution, i.e., the ability of the genome to expand its functional possibilities; on the other hand, CpG-related mutations in SNPs would relate to genomic ‘specificity’ in evolution, thus, representing mutations that would associate with phenotypic traits relevant for speciation.</p