18,268 research outputs found

    Mapeamento digital de classes e atributos de solos: métodos, paradigmas e novas técnicas.

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    Panorama geral sobre os métodos de mapeamento de solos e/ou de suas propriedades, assim como sobre as principais técnicas quantitativas usadas.bitstream/CNPS/11588/1/doc55_mapeamentodigital.pd

    Determinação do número de amostras de solo para análise química em diferentes condições de manejo.

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    Com o objetivo de estabelecer o melhor procedimento na coleta de amostras de solos para analise quimica, utilizaram-se, em uma area de 6 ha de um Latossolo Vermelho-Escuro distrofico (LEd) fase cerrado, textura argilosa, em Sete Lagoas, MG, diferentes criterios de amostragens: (A) trinta amostras simples; (B) dez amostras compostas, formadas de cinco simples; (C) cinco amostras compostas formadas de dez simples e (D) cinco amostras compostas formadas de vinte simples, em tres etapas de manejo: (1) area recem-desmatada; (2) arada e gradeada e (3) cultivada com milho apos correcao do solo. Os resultados evidenciaram que (a) a variancia diminuiu das amostras simples para as compostas; (b) as menores variacoes foram observadas para pH, Al e M.O. e as maiores para P, Ca. Mg e K; (c) para uma variacao de 20% em torno da media a 80% de probabilidade e com base na variabilidades dos teores de P, Ca e Mg, recomenda-se para os 6 ha a retirada de 9, 7 e 15 amostras, formadas, cada uma, de 10 amostras simples, respectivamente para as etapas 1, 2 e 3. Com 95% de probabilidade, recomenda-se a retirada de 17 e 42 amostras formadas cada uma de 5 simples para as etapas 1 e 3 respectivamente. Na etapa 2, retirar 13 amostras compostas formadas cada uma de 20 amostras simples

    Controle integrado da broca da haste da mandioca Sternocoelus spp.

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    Consideradas pragas secundárias, as brocas da haste da mandioca Sternocoelus spp. (Coleoptera: Curculionidae) são problema fitossanitário em algumas áreas produtoras (RODRIGUEZ et al., 2009). O controle dessa praga é difícil, pois o dano ocorre quando ao eclodir e se alimentar no interior da haste as larvas interrompem o fluxo de seiva na planta levando-a à morte (CARVALHO et al. 2009)

    Towards sustainability in European agricultural firms

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    European agricultural activity plays an important role in European and world food security through the agricultural production, supply and international trade. The main aim of this paper was analyses the agricultural sustainability of the twenty-nine Member States of the European Union in terms of economics, environmental, social and political activity. Information and data comes from FADN database from the European Commission. The methodology includes the min-max approach and multivariate methods, namely, Component Principal Analysis and Cluster analysis. The results confirm three groups of European countries, namely, the North and Central countries; the New Member States and the Mediterranean counties. The results also confirm that European agriculture firms and respective countries had a medium sustainability. The main conclusion highlines confirms the importance of the sustainability as a tool to better adjust agricultural policies among the European Member States.info:eu-repo/semantics/acceptedVersio

    Dois ciclos de seleção entre e dentro de famílias de meios-irmãos na variedade de milho BR 5028 São Francisco.

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    Modelling and digital soil mapping of the organic carbon stock in the topsoil (0-10 cm) of Rio de Janeiro State, Brazil.

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    A soil database with 431 soil profiles of Rio de Janeiro State was used in the scope of a research project entitled "Quantifying the magnitude, spatial distribution and organic carbon in soils of Rio de Janeiro State, using quantitative modeling, GIS and database technologies" (Projeto Carbono_RJ, funded by FAPERJ - Carlos Chagas Filho Foundation for Research Support in Rio de Janeiro State). Considering that these soil data were collected to other purpose, there was only a few sparse data to soil bulk density, which is essential to estimate of soil organic carbon (SOC) stock. To face this problem, pedotransfer functions (PTFs) were estimated to be used in the modeling of organic soil carbon of topsoil (0-10 cm), using s.c.o.r.p.a.n model. The following environmental correlates were used as predictor variables: satellite data, lithology and soil maps, DEM (Digital Elevation Model) and its derivatives as source of information for these variables. This dataset, that represents the best organized soil dataset in Brazil, is working as a trial for learning/teaching of Digital Soil Mapping (DSM) using a variety of methods for predicting soil classes and their properties. The "f" of the equation was modeled by means of multilinear analysis and regression-kriging. Seven different models were built and compared through statistical methods. In a general way, all models performed well to predict the SOC stock. Nevertheless, model 6 (M6) was an exceptional model, presenting the smallest AIC e RMSE, due to the use of existing soil information (polygon soil map) as predictor variable, in addition to the variables used in the other models. The result obtained in M6 was used for mapping topsoil carbon stock at spatial resolution of 90 m
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