Cadmium availability and accumulation by lettuce and rice

Among the toxic elements, Cd has received considerable attention in view of its association with a number of human health problems. The objectives of this study were to evaluate the Cd availability and accumulation in soil, transfer rate and toxicity in lettuce and rice plants grown in a Cd-contaminated Typic Hapludox. Two simultaneous greenhouse experiments with lettuce and rice test plants were conducted in a randomized complete block design with four replications. The treatments consisted of four Cd rates (CdCl2), 0.0; 1.3; 3.0 and 6.0 mg kg(-1), based on the guidelines recommended by the Environmental Agency of the State of São Paulo, Brazil (Cetesb). Higher Cd rates increased extractable Cd (using Mehlich-3, Mehlich-1 and DTPA chemical extractants) and decreased lettuce and rice dry matter yields. However, no visual toxicity symptoms were observed in plants. Mehlich-1, Mehlich-3 and DTPA extractants were effective in predicting soil Cd availability as well as the Cd concentration and accumulation in plant parts. Cadmium concentration in rice remained below the threshold for human consumption established by Brazilian legislation. on the other hand, lettuce Cd concentration in edible parts exceeded the acceptable limit.

Extratores para avaliação da disponibilidade de metais pesados em solos adubados com vermicomposto de lixo urbano

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Disponibilidade de níquel em solo tratado com lodo de esgoto e cultivado com sorgo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Assessment of micronutrient extractants from soils of Paraná, Brazil

In Brazil, plant-available micronutrients in the soil can be determined by several chemical extractants, the most common of which are dilute acid and chelating solutions. The purpose of this study was to assess the extractants 0.1 mol L-1 HCl, Mehlich-1, Mehlich-3 and DTPA for analysis of the micronutrients Cu, Zn, Fe, and Mn in soils from the state of Parana. In samples from 12 soils (0-20 cm layer), wheat was planted (Triticum aestivum), grown for 42 days after emergence, and then bean (Phaseolus vulgaris) for 38 days. At the end of each planting period, the soil was sampled again. All extractants tested to assess the availability of Cu, Zn, Fe, and Mn correlated with each other. The efficiency of the extractants HCl, Mehlich-3 and DTPA in assessing plant-available Cu was similar, unlike Mehlich-1, which proved less efficient. The extractants HCl, Mehlich-1 and Mehlich-3 were less efficient in estimating plant-available Zn and Fe, and the most indicated extractant is DTPA. The efficiency of the extractants HCl, Mehlich-1, Mehlich-3 and DTPA in assessing plant-available Mn in soils from Parana was similar.

Extraction methods and availability of phosphorus for soybean in soils from Parana State, Brazil

In studies on the evaluation of methodologies for the analysis of soil, phosphorus (P) has been the single most studied aspect, due to the complexity of this dynamic element in soil. However, these studies have been limited regarding soil conditions in Paranaa. The present study aimed to evaluate the efficiency of the Mehlich-1, Mehlich-3 and ion exchange resin methods in the evaluation of available P for soybean (Glycine max) in the soils of Paranaa State. Twelve soil samples collected from the upper 0-20 cm were planted with soybean for a period of 42 days in the greenhouse. The ability to extract soil P followed the order of decreasing average amount of extracted P: Mehlich-3 > resin > Mehlich-1. The correlation coefficients between the content of P extracted by Mehlich-1, Mehlich-3 and resin and the amount of P accumulated in the plants were 0.86, 0.90 and 0.93, respectively. Mehlich-1, Mehlich-3 and resin showed similar efficiency in the evaluation of P availability to plants and, under conditions of natural fertility and in soils that had received no application of poorly natural reactive phosphates, can be used to quantify the concentrations of P in the soils of Parana State.

Metais pesados do solo após aplicação de biossólido: I - Fracionamento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Metais pesados do solo após aplicação de biossólido: II - Disponibilidade

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nickel in a tropical soil treated with sewage sludge and cropped with maize in a long-term field study

Sewage sludge produced by the SABESP wastewater treatment plant (Companhia de Saneamento Básico do Estado de São Paulo), located in Barueri, SP, Brazil, may contain high contents of nickel (Ni), increasing the risk of application to agricultural soils. An experiment was carried out under field conditions in Jaboticabal, SP, Brazil, with the objective of evaluating the effects on soil properties and on maize plants of increasing rates of a sewage sludge rich in Ni that had been applied for 6 consecutive years. The experiment was located on a Typic Haplorthox soil, using an experimental design of randomized blocks with four treatments (rates of sewage sludge) and five replications. At the end of the experiment the accumulated amounts of sewage sludge applied were 0.0, 30.0, 60.0 and 67.5 t ha-1. Maize (Zea mays L.) was the test plant. Soil samples were collected 60 d after sowing at depths of 0-20 cm for Ni studies and from 0 to 10 cm and from 10 to 20 cm for urease studies. Sewage sludge did not cause toxicity or micronutrient deficiencies to maize plants and increased grain production. Soil Ni appeared to be associated with the most stable fractions of the soil organic matter and was protected against strong extracting solutions such as concentrated and hot HNO3 and HCl. Ni added to the soil by sewage sludge increased the metal concentration in the shoots, but not in the grain. The Mehlich 3 extractor was not efficient to evaluate Ni phytoavailability to maize plants. Soil urease activity was increased by sewage sludge only in the layer where the residue was applied. © 2006 Elsevier Ltd. All rights reserved.

Adubação com manganês em soja: efeitos no solo e na planta

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Adsorção de cádmio e disponibilidade de cádmio e bário em latossolos sob mata nativa e cultivados

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Propriedades químicas de um latossolo tratado com lodo de esgoto e efeitos na cultura do milho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Potencial do eucalipto na fitorremediação de um solo contaminado por chumbo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Disponibilidade de bário para plantas de sorgo cultivadas em solo contaminado com o elemento

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Nitrogênio, arsênio, bário e estado nutricional de plantas de milho cultivadas em latossolos tratados com lodo de esgoto

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Micronutrient contents of a revegetated saprolite exposed by excavation of an oxisol

Soils of the Brazilian Cerrado biome have been found to be deficient in copper (Cu) and zinc (Zn). In this area, an Oxisol was deeply excavated in 1962 during the construction of a hydroelectrical plant, and the exposed saprolite material was abandoned, without any reclamation measures. The abandoned land was a harsh environment for plant growth, and the secondary vegetation has not recovered. A field trial was established in 1992 to assess the effects of different grass species and lime amendments on soil reclamation at the degraded site. In 2011 soil samples were collected at three depths (0-10, 10-20, and 20-40cm) from vegetated and bare plots over tilled saprolite, from an untreated area of the saprolite, and from an Oxisol under native forest, used as external reference. Nineteen years after the reclamation effort was begun, the organic carbon (OC) content of the restored saprolite still was much lower than that of the Oxisol under natural vegetation. The undisturbed Oxisol was deficient in extractable Cu (0.16-0.10mgkg(-1)) and Zn (0.10-0.02mgkg(-1)) and exhibited rather low concentrations of extractable iron (Fe; 5.24-1.47mgkg(-1)) and manganese (Mn; 3.21-0.77mgkg(-1)). However, the saprolite under reclamation showed even lower levels of these elements compared to the native forest soil. In the natural soil, OC, N, extractable Fe, Mn, and Cu showed stratification, but this was not the case for extractable Zn. Although the reclaimed saprolite still was far from predisturbance conditions, the revegetation treatments promoted recovery of OC, N, Fe, Mn, and Cu at the surface layers, which resulted in incipient stratification. Extractable Fe, Mn, and Cu were correlated to OC, whereas no association between Zn and OC was detected. Our results also suggest that reclamation of the excavated saprolite may be constrained by micronutrient deficiencies and mostly by the extremely low levels of Zn and Cu.