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147 results on '"Parent, Léon-Étienne"'

3. Phytoremediation of Cu‐contaminated vineyard soils in Brazil: A compendium of Brazilian pot studies

Author

Marques, Anderson Cesar Ramos, primary, Tiecher, Tadeu Luis, additional, Brunetto, Gustavo, additional, Vendruscolo, Diogo, additional, De Conti, Lessandro, additional, Ambrosini, Vitor Gabriel, additional, Miotto, Alcione, additional, Rosa, Daniel José, additional, da Silva, Isley Cristiellem Bicalho, additional, Trentin, Edicarla, additional, Ferreira, Paulo Ademar Avelar, additional, Jacques, Rodrigo Josemar Seminoti, additional, Pescador, Rosete, additional, Comin, Jucinei José, additional, Ceretta, Carlos Alberto, additional, de Melo, George Wellington Bastos, additional, and Parent, Léon‐Étienne, additional

Published
2023
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6. Customized nutrient management of onion (Alium cepa) agroecosystems

Author

Hahn, Leandro, primary, Kurtz, Claudinei, additional, Paula, Betania Vahl, additional, Feltrim, Anderson Luiz, additional, Higashikawa, Fábio Satoshi, additional, Moreira, Camila, additional, Rozane, Danilo Eduardo, additional, Brunetto, Gustavo, additional, and Parent, Léon-Étienne, additional

Published
2023
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10. Local Factors Impact Accuracy of Garlic Tissue Test Diagnosis

Author

Hahn, Leandro, primary, Parent, Léon-Étienne, additional, Feltrim, Anderson Luiz, additional, Rozane, Danilo Eduardo, additional, Ender, Marcos Matos, additional, Tassinari, Adriele, additional, Krug, Amanda Veridiana, additional, Berghetti, Álvaro Luís Pasquetti, additional, and Brunetto, Gustavo, additional

Published
2022
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11. Prediction of Nitrogen Dosage in ‘Alicante Bouschet’ Vineyards with Machine Learning Models

Author

Brunetto, Gustavo, primary, Stefanello, Lincon Oliveira, additional, Kulmann, Matheus Severo de Souza, additional, Tassinari, Adriele, additional, Souza, Rodrigo Otavio Schneider de, additional, Rozane, Danilo Eduardo, additional, Tiecher, Tadeu Luis, additional, Ceretta, Carlos Alberto, additional, Ferreira, Paulo Ademar Avelar, additional, Siqueira, Gustavo Nogara de, additional, and Parent, Léon Étienne, additional

Published
2022
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14. Long-Term Effects of Animal Manures on Nutrient Recovery and Soil Quality in Acid Typic Hapludalf under No-Till Conditions

Author

Ferreira, Paulo Ademar Avelar, primary, Ceretta, Carlos Alberto, additional, Lourenzi, Cledimar Rogério, additional, De Conti, Lessandro, additional, Marchezan, Carina, additional, Girotto, Eduardo, additional, Tiecher, Tadeu Luis, additional, Palermo, Natália Moreira, additional, Parent, Léon-Étienne, additional, and Brunetto, Gustavo, additional

Published
2022
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26. Comments on “Variability in Corn Response to Nitrogen Fertilizer in Eastern Canada” by L.A. Kablan, V. Chabot, A. Mailloux, M.E. Bouchard, D, Fontaine, and T. Bruulsema, Agron. J. 109:2231–2242 (2017)

Author

Parent, Léon‐Étienne, primary, Tremblay, Gilles, additional, Robert, Louis, additional, Faucher, Yvan, additional, Kablan, Lucie A, additional, Chabot, Valérie, additional, Mailloux, Alexandre, additional, and Bruulsema, Tom, additional

Published
2018
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31. Compositional meta-analysis of citrus varieties in the state of São Paulo, Brazil

Author

Rozanne, Danilo Eduardo, Mattos Junior, Dirceu de, Parent, Serge-Étienne, Natale, William, Parent, Léon-Étienne, and Universitat de Girona. Departament d'Informàtica i Matemàtica Aplicada

Subjects
Biologia -- Mètodes estadístics -- Congressos, Quantitative research, Estadística matemàtica -- Congressos, Matemàtiques i estadística::Estadística matemàtica [Àrees temàtiques de la UPC], Investigació quantitativa, Data analytics, Anàlisi multivariable -- Congressos, Ecology -- Statistical methods -- Congresses, Mathematical statistics -- Congresses, Ecologia -- Mètodes estadístics -- Congressos, Biology -- Statistical methods -- Congresses
Abstract

Brazil is the largest orange (Citrus sinensis) producer worldwide. The nutrient management of orange orchards is designed from experiments on a limited number of varieties. This knowledge is transferred to other varieties by diagnosing tissue nutrient composition. Nutrient diagnostic tools are based on nutrient concentration (critical minimum value or CMV) and ratio (Diagnosis and Recommendation Integrated System or DRIS) norms that disregard the compositional nature of analytical data and the limited number of nutrient ratios that can be diagnosed independently in a given composition. The diagnosis of cationic micronutrients is also biased by contamination from fungicides. Compositional data analysis that can avoid such problems has been first applied to tissue analysis of agricultural crops using centered log ratios (Compositional Nutrient Diagnosis – CND-clr). The isometric log ratio (ilr) transformation is a new approach based on binary nutrient ratios and the principle of orthogonality (CND-ilr). Binary partitions can be defined and varietal nutrient profiles classified based on positive and negative nutrient interactions and meta-analysis. We analyzed 11 nutrients (N, S, P, K, Ca, Mg, B, Cu, Zn, Mn, Fe) in tissue samples across 108 orchard areas, i.e. 31 ‘Valencia’, 22 ‘Hamlin’, 20 ‘Pêra’, and 35 ‘Natal’. Nutrients were partitioned between macro- and micro-nutrients as well as anionic and cationic species. The effect size of varieties over ‘Valencia’ was quantified by the mean and standard deviation of ilr values across ilr coordinates. Specific varietal nutrient profiles and ilr norms were defined. To guide correcting nutrient deficiencies by appropriate nutrient management, compositions can be varied by a perturbation vector on nutrients with to the largest and most negative influence on ilr differences from ilr norms until the Aitchison distance falls below critical value.

Published
2011

32. Fractal and compositional analysis of soil aggregation

Author

Parent, Léon-Étienne, Parent, Serge-Étienne, Kätterer, Thomas, Egozcue, Juan José, and Universitat de Girona. Departament d'Informàtica i Matemàtica Aplicada

Subjects
Biologia -- Mètodes estadístics -- Congressos, Quantitative research, Estadística matemàtica -- Congressos, Fractals -- Congressos, Matemàtiques i estadística::Estadística matemàtica [Àrees temàtiques de la UPC], Investigació quantitativa, Data analytics, Anàlisi multivariable -- Congressos, Mathematical statistics -- Congresses, Biology -- Statistical methods -- Congresses
Abstract

A soil aggregate is made of closely packed sand, silt, clay, and organic particles building up soil structure. Soil aggregation is a soil quality index integrating the chemical, physical, and biological processes involved in the genesis of soil structure and tilth. Aggregate size distribution is determined by sieving a fixed amount of soil mass under mechanical stress and is commonly synthesized by the mean weight diameter (MWD) and fractal dimensions such as the fragmentation fractal dimensions (D f). A fractal is a rough object that can be broken down into a number of reduced-size copies of the original object. Equations have been developed to compute bounded and unbounded scaling factors as measures of fractal dimensions based on assumptions about average diameter, bulk density, shape and probability of failure of sieved particles. The log-log relationship between particle diameter and cumulative number or mass of aggregates or soil particles above a given diameter often shows more or less uniform fractal patterns. Multi-fractal (slopes showing several D f values ≤ 3) and non fractal patterns or incomplete fragmentation ( D f < 2 or > 3) have been reported. Scaling factors are curve- fitting parameters that are very sensitive to the choice of the fractal domain about breakpoints. Compositional data analysis using sequential binary partitions for isometric log ratio (ilr) coordinates with orthonormal basis provides a novel approach that avoids the assumptions and dimensional constraints of fractal analysis. Our objective was to compare MWD, fractal scaling factors and ilr coordinates using published data. In the first dataset, MWD was found to be biased by excessively high weight being given to the largest aggregate-size. Eight ilr coordinates contrasting micro- vs. macro-aggregates were related to fragmentation fractal dimensions, most of which were below 2 or above 3, a theoretical impossibility for geometric fractals. The critical ilr value separating scaling factors 3 and > 3 was close to zero. In a second dataset, the Aitchison distance computed across ilr coordinates proved to be a useful measure of the degree of soil aggregation, agradation or degradation against a reference composition such as that of primary particles, bare fallow or permanent grass. The individual contributions of ilr coordinates to the Aitchison distance can be interpreted in terms of sign and amplitude and be related to soil properties and processes mediated by soil aggregation.

Published
2011

33. Compositional analysis of phosphorus pools in Canadian Mollisols

Author

Abdi, D., Ziadi, N., Parent, Léon-Étienne, and Universitat de Girona. Departament d'Informàtica i Matemàtica Aplicada

Subjects
Quantitative research, Estadística matemàtica -- Congressos, Matemàtiques i estadística::Estadística matemàtica [Àrees temàtiques de la UPC], Investigació quantitativa, Data analytics, Sòls -- Mètodes estadístics -- Congressos, Anàlisi multivariable -- Congressos, Mathematical statistics -- Congresses, Soils -- Statistical methods -- Congresses
Abstract

During cultivation, the internal phosphorus cycle of Mollisols (Chernozems) of the Canadian Prairies is perturbed by crop sequences including wheat phases, tillage practices, and regular applications of fertilizers. To monitor these changes, a proximate sequential phosphorus (P) fractionation procedure was developed by Hedley et al. (1982) to extract inorganic and organic P fractions as very labile (resin-P), labile (NaHCO3-P), slowly available (NaOH-P), and very slowly available (HCl-P) pools. Models used so far to monitor P pools do not address the interactive behaviour of P fractions constrained to a closed compositional space. Compositional data analysis using isometric log ratio (ilr) coordinates is appropriate for modelling the interactive P pools using sequential binary partitions of P pools. Our objective was to model changes of P pools in Mollisols in response to management and time using ilr coordinates. We used a dataset with treatments and another where a Mollisol was analyzed at time zero and 4, 65, and 90 yr after sod breakup. Seven P fractions were assigned to P reactivity groups to compute six ilr coordinates. The ilr2 contrasting inorganic (geochemical) and organic (biological) P pools and ilr4 between the most readily available and less P bioavailable pools were the most sensitive to crop sequence and fertilization. Using composition at time zero as reference, the Aitchison distance reached a plateau after the 4th year in the Bm horizon compared to continuous change in the Ah horizon. Time changed the P balance of cultivated Mollisols primarily in the inorganic vs. organic P pools. The risks of yield loss and environmental damage can be minimized using soil tests that quantify the rapidly bioavailable inorganic P pools and crop management strategies that promote biological P pools.

Published
2011

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