Validação cruzada com correção de autovalores e regressão isotônica nos modelos de efeitos principais aditivos e interação multiplicativa

Piovesan, Pamela; Araújo, Lúcio Borges de; Dias, Carlos Tadeu dos Santos

doi:10.1590/s0103-84782009005000081

Cited by 11 publications

(10 citation statements)

References 10 publications

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“…Subsequently, we scaled up the number of variables according to their characteristics to better visualize the interaction between the variables in the coordinate axes. These new axes, the eigenvectors (new variables) called principal components (PC), are generated by linear combinations of the original variables constructed from the eigenvalues of the covariance matrix (Hair 2007;Piovesan et al 2008). In order to obtain a simpler and more parsimonious model, we used the Kaiser criterion (1958) with eigenvectors above the unit.…”

Section: Data Processing and Statistical Analysismentioning

confidence: 99%

For how long does the quality and quantity of residues in the soil affect the carbon compartments and CO2-C emissions?

et al. 2016

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Purpose The mineralization/immobilization of nutrients from the crop residues is correlated with the quality of the plant material and carbon compartments in the recalcitrant and labile soil fractions. The objective of this study was to correlate the quality and quantity of crop residues incubated in the soil with carbon compartments and CO 2 -C emission, using multivariate analysis. Materials and methods The experiment was conducted in factorial 4 + 2 + 5 with three replicates, referring to three types of residues (control, sugarcane, Brachiaria, and soybean), and two contributions of the crop residues in constant rate, CR (10 Mg ha −1 residue), and agronomic rate, AR (20, 8, and 5 Mg ha −1 residue, respectively, for sugarcane, soybean, and Brachiaria), evaluated five times (1, 3, 6, 12, and 48 days after incubation). At each time, we determined the CO 2 -C emission, nitrogen and organic carbon in the soil, and the residues. In addition, the microbial biomass and water-soluble, labile, and humic substance carbons fractionated into fulvic acids, humic acids and humin were quantified.Results and discussion Higher CO 2 -C emissions occurred in the soil with added residue ranging from 0.5 to 1.1 g CO 2 -C m −2 h −1 in the first 6 days of incubation, and there was a positive correlation with the less labile organic soil fractions as well as residue type. In the final period, after 12 days of soil incubation, there was a higher relation of CO 2 -C emission with carbon humin. The sugarcane and soybean residue (20 Mg ha −1 ) promoted higher CO 2 -C emission and the reduction of carbon residue. The addition of residue contributed to an 82.32 % increase in the emission of CO 2 -C, being more significant in the residue with higher nitrogen availability. Conclusions This study shows that the quality and quantity of residue added to soil affects the carbon sequestration and CO 2 -C emission. In the first 6 days of incubation, there was a higher CO 2 -C emission ratio which correlates with the less stable soil carbon compartments as well as residue. In the final period of incubation, there is no effect of quality and quantity of residue added to soil on the CO 2 -C emission.

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Section: Data Processing and Statistical Analysismentioning

confidence: 99%

For how long does the quality and quantity of residues in the soil affect the carbon compartments and CO2-C emissions?

et al. 2016

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“…Assim, o conjunto de variáveis agrupado de acordo com suas características para melhor visualização da relação entre as variáveis em eixos das coordenadas. Nesses novos eixos, os autovalores (novas variáveis) chamados de componentes principais (CP) são gerados por combinações lineares das variáveis originais associados com os autovalores da matriz de covariância (Hair et al, 2005;Piovesan, 2008). Após a padronização dos dados (média nula e variância unitária), as análises foram conduzidas no programa STATISTICA 7.0 (StatSoft.…”

Section: Processamento Dos Dados E Análise Estatísticaunclassified

Características agronômicas de cultivares de milho verde submetidas a doses de Ribumin®

et al. 2016

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“…Next, the set of variables were grouped according to their characteristics for better visualization of the relationship between the variables on the axes of coordinates. The new axis and the auto-vectors (new variables) called principal components (CP), are generated by linear combinations of the original variables constructed with the auto-values of the covariance matrix (HAIR et al, 2005;PIOVESAN, 2008). With the goal of obtaining a model more simple and parsimonious, we used the Kaiser criterion (1958), with auto-vectors above the unit.…”

Section: Soilmentioning

confidence: 99%

SOIL ATTRIBUTES IN CONVENTIONAL TILLAGE OF Coffea arabica L.: A CASE STUDY

Mota

Almeida

Lemes

et al. 2018

C.Sci.

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Coffee production presents great economic and social importance. To increases coffee production and decreases the environmental impacts of its activity, it is necessary to know the soil attributes and their impacts on plant development. Therefore, due to the importance of the soil physical and chemical attributes, as well as the significance of coffee to Brazil, the objective of this study was to evaluate the physical and chemical attributes of an Oxisol planted with coffee conducted under conventional tillage system. For the purposes of analysis and interpretation of the data, the experiment was performed and interpreted in a completely randomized design, with the factorial 3 x 2, referring to three locations in the area of the coffee plantation (planting line, canopy projection, between planting lines) and two soil layers (0 -0.2 m and 0.2 -0.4 m), with four replications. It is concluded that no distinctions for soil porosity and total porosity was observed among soil locations, and that 'planting line' position showed superior concentrations of total organic carbon and mean geometric diameter of the soil aggregates.Index terms: Coffee, soil aggregates, soil organic carbon, macroporosity, microporosity. ATRIBUTOS DO SOLO COM PLANTIO CONVENCIONAL DE Coffea arabica L.:UM ESTUDO DE CASO RESUMO: A produção de café (Coffea arabica) apresenta grande importância socioeconômica no Brasil. Para melhor desenvolvimento da cultura e redução de impactos ambientais, faz-se necessário conhecer os atributos do solo. Dada a importância dos atributos físicos e químicos do solo, bem como a posição de destaque do Estado de Minas Gerais como maior produtor de café do Brasil, o objetivo do estudo foi avaliar os atributos físicos e químicos de um Latossolo Vermelho textura argilosa em uso com café manejado em sistema de plantio convencional, na Região do Triângulo Mineiro. Para efeito de análise e interpretação da exploração dos dados, o experimento foi realizado e interpretado em esquema de delineamento inteiramente casualizado -DIC, com o fatorial 3 x 2, referente a três localizações na área do cafezal (tronco, saia e rua) e duas camadas (0,0 -0,2 e 0,2 -0,4 m), com quatro repetições. Conclui-se que a posição do tronco do cafeeiro apresentou maiores concentrações de carbono orgânico total e diâmetro médio geométrico, enquanto que para macroporosidade e porosidade total não houve distinções entre os tratamentos.Termos para indexação: Café, agregados do solo, carbono orgânico do solo, macroporosidade, microporosidade.

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Validação cruzada com correção de autovalores e regressão isotônica nos modelos de efeitos principais aditivos e interação multiplicativa

Cited by 11 publications

References 10 publications

For how long does the quality and quantity of residues in the soil affect the carbon compartments and CO2-C emissions?

For how long does the quality and quantity of residues in the soil affect the carbon compartments and CO2-C emissions?

Características agronômicas de cultivares de milho verde submetidas a doses de Ribumin®

SOIL ATTRIBUTES IN CONVENTIONAL TILLAGE OF Coffea arabica L.: A CASE STUDY

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