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All publications of “Roberto Ferreira Novais”

55 results

Physiological Responses to Hypoxia and Manganese in Eucalyptus Clones with Differential Tolerance to Vale do Rio Doce Shoot Dieback

Ignácio Harguindeguy, Gustavo Franco de Castro, Sarah Vieira Novais, Leonardus Vergutz, Wagner Luiz Araujo, Roberto Ferreira Novais

19/Jan/2018

ABSTRACT: Vale do Rio Doce shoot dieback (VRDSD) is an anomaly whose cause seems to be associated with hypoxic conditions and their consequences (excess Mn and Fe) triggered by elevation of the water table in areas with poor drainage. Different plants have distinct survival strategies under this form of stress. The objective of this study was to understand the physiological responses involved in the differential tolerance of eucalyptus clones to VRDSD and their relationship to hypoxia and excess Mn. A […]

Phosphorus-Zinc Interaction and Iron and Manganese Uptake in the Growth and Nutrition of Phalaenopsis (Orchidaceae)

Sarah Vieira Novais, Roberto Ferreira Novais, Víctor Hugo Alvarez V., Ecila Mercês de Albuquerque Villani, Mariana Delgado Oliveira Zenero

09/Dec/2016

ABSTRACT: Visual symptoms of Zn deficiency, induced by excessive P applications, have been observed in commercial orchid nurseries. The supply of other metallic micronutrients, such as Fe and Mn, may also be inadequate in the plant due to high application rates of P. The aim of this study was to investigate this interaction in the nutrition of Phalaenopsis plants. Experimental treatments consisted of three P rates (0.0, 0.5, and 1.0 g L-1) and three Zn rates (0.00, 0.35, and 0.70 […]

Iron Availability in Tropical Soils and Iron Uptake by Plants

Guilherme Furlan Mielki, Roberto Ferreira Novais, João Carlos Ker, Leonardus Vergütz, Gustavo Franco de Castro

05/Oct/2016

ABSTRACT Given the increase in crop yields and the expansion of agriculture in low fertility soils, deficiency of micronutrients, such as iron, in plants grown in tropical soils has been observed. The aim of this study was to evaluate Fe availability and Fe uptake by corn (Zea mays L.) plants in 13 different soils, at two depths. Iron was extracted by Mehlich-1, Mehlich-3, and CaCl2 (Fe-CC) and was fractionated in forms related to low (Feo) and high (Fed) crystallinity pedogenic […]

Diagnosis of the Nutritional Status of Garlic Crops

Mário Lúcio Pereira Cunha, Leonardo Angelo Aquino, Roberto Ferreira Novais, Junia Maria Clemente, Priscila Maria de Aquino and, Thaisa Fernanda Oliveira

12/Apr/2016

ABSTRACT Univariate methods for diagnosing nutritional status such as the sufficiency range and the critical level for garlic crops are very susceptible to the effects of dilution and accumulation of nutrients. Therefore, this study aimed to establish bivariate and multivariate norms for this crop using the Diagnosis and Recommendation Integrated System (DRIS) and Nutritional Composition Diagnosis (CND), respectively. The criteria used were nutritional status and the sufficiency range, and then the diagnoses were compared. The study was performed in the […]

Thermodynamic Characterization of Humic Acid-surfactant Interaction: New Insights into the Characteristics and Structure of Humic Acids

Leonardus Vergütz, Luis Henrique Mendes da Silva, Roberto Ferreira Novais, Maria do Carmo Hespanhol da Silva, Aparecida Barbosa Mageste, Ivo Ribeiro Silva

01/Dec/2015

ABSTRACT Humic acids (HA) are a component of humic substances (HS), which are found in nearly all soils, sediments, and waters. They play a key role in many, if not most, chemical and physical properties in their environment. Despite the importance of HA, their high complexity makes them a poorly understood system. Therefore, understanding the physicochemical properties and interactions of HA is crucial for determining their fundamental role and obtaining structural details. Cationic surfactants are known to interact electrostatically and […]

NUTRIENT RECOMMENDATION MODEL FOR CARROT CROP – FERTICALC CARROT

Luciel Rauni Dezordi, Leonardo Angelo de Aquino, Roberto Ferreira Novais, Priscila Maria de Aquino, Luiz Paulo Dornelas dos Santos

01/Dec/2015

ABSTRACT The literature on fertilization for carrot growing usually recommends nutrient application rates for yield expectations lower than the yields currently obtained. Moreover, the recommendation only considers the results of soil chemical analysis and does not include effects such as crop residues or variations in yield levels. The aim of this study was to propose a fertilizer recommendation system for carrot cultivation (FERTICALC Carrot) which includes consideration of the nutrient supply by crop residues, variation in intended yield, soil chemical […]

SEQUENTIAL EXTRACTION OF PHOSPHORUS BY MEHLICH-1 AND ION EXCHANGE RESIN FROM B HORIZONS OF FERRIC AND PERFERRIC LATOSOLS (OXISOLS)

Danilo de Lima Camêlo, João Carlos Ker, Roberto Ferreira Novais, Marcelo Metri Corrêa, Vinício Coelho de Lima

01/Jul/2015

In general, Latosols have low levels of available P, however, the influence of the parent material seems to be decisive in defining the pool and predominant form of P in these soils. This study evaluated P availability by extraction with Mehlich-1 (M-1) and Ion Exchange Resin (IER), from samples of B horizons of Ferric and Perferric Latosols developed from different parent materials. To this end, in addition to the physical and chemical characterization of soils, 10 sequential extractions were performed […]

LOSS OF EXTRACTION CAPACITY OF MEHLICH-1 AND MONOCALCIUM PHOSPHATE AS A VARIABLE OF REMAINING P AND ITS RELATIONSHIP TO CRITICAL LEVELS OF SOIL PHOSPHORUS AND SULFUR

Sarah Vieira Novais, Edson Marcio Mattiello, Leonardus Vergutz, Leônidas Carrijo Azevedo Melo, Írio Fernando de Freitas, Roberto Ferreira Novais

01/Jul/2015

The Mehlich-1 (M-1) extractant and Monocalcium Phosphate in acetic acid (MCPa) have mechanisms for extraction of available P and S in acidity and in ligand exchange, whether of the sulfate of the extractant by the phosphate of the soil, or of the phosphate of the extractant by the sulfate of the soil. In clayey soils, with greater P adsorption capacity, or lower remaining P (Rem-P) value, which corresponds to soils with greater Phosphate Buffer Capacity (PBC), more buffered for acidity, […]

LEAF TOTAL NITROGEN CONCENTRATION AS AN INDICATOR OF NITROGEN STATUS FOR PLANTLETS AND YOUNG PLANTS OF EUCALYPTUS CLONES

Eric Victor de Oliveira Ferreira, Roberto Ferreira Novais, Bruna Maximiano Médice, Nairam Félix de Barros, Ivo Ribeiro Silva

01/Jul/2015

The use of leaf total nitrogen concentration as an indicator for nutritional diagnosis has some limitations. The objective of this study was to determine the reliability of total N concentration as an indicator of N status for eucalyptus clones, and to compare it with alternative indicators. A greenhouse experiment was carried out in a randomized complete block design in a 2 × 6 factorial arrangement with plantlets of two eucalyptus clones (140 days old) and six levels of N in […]

Differential Behavior of Young Eucalyptus Clones in Response to Nitrogen Supply

Eric Victor de Oliveira Ferreira, Roberto Ferreira Novais, Greice Leal Pereira, Nairam Félix de Barros, Ivo Ribeiro da Silva

01/May/2015

Eucalyptus requires large amounts of nitrogen (N); however, it responds in diverse manners to the application of this nutrient. The aim of this study was to evaluate the differential performance in growth, mineral nutrition, and gas exchanges of N-fertilized Eucalyptus clones. The treatments consisted of two Eucalyptus clones (VM-01 and I-144) and six N application rates (0, 0.74, 2.93, 4.39, 5.85, and 8 mmol L-1 NH4NO3) arranged in a randomized complete block design with five replications. VM-01 had greater plant […]

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