Toxicidade do níquel em plantas de feijão e efeitos sobre a microbiota do solo

Abstract

Resumo -O objetivo deste trabalho foi avaliar o efeito da adição de Ni ao solo (0, 2,3, 10,5, 47 e 210 mg kg -1 ), na presença e ausência de calcário, sobre: o desenvolvimento do feijoeiro; a fitodisponibilidade de Ni e algumas características biológicas do solo. O experimento foi conduzido em casa de vegetação, em Latossolo Vermelho distrófico. A dose de Ni de 210 mg kg -1 causou a morte de todas as plantas, tanto na presença como na ausência de calcário. Houve aumento da produção de grãos de feijão no tratamento que recebeu calcário. A concentração de Ni dos grãos aumentou com o incremento de Ni no solo, ultrapassando o limite máximo permitido, de 5 mg kg -1 de matéria fresca, na dose de 2,3 mg kg -1 , indicando que a aplicação de calcário não foi suficiente para reduzir os teores de Ni no grão de feijão a níveis apropriados para o consumo. Observou-se diminuição da biomassa microbiana do solo nos tratamentos com altas concentrações de Ni, que foi acompanhada por aumento no qCO 2 . O qCO 2 foi um indicador adequado do grau de estresse que teve a comunidade microbiana do solo com a adição de Ni.Termos para indexação: absorção de Ni, DTPA, biomassa microbiana, respiração do solo, qCO 2 . Nickel toxicity in common bean plants and effects on soil microbiotaAbstract -The aim of this work was to evaluate the effect of Ni addition (0, 2.3, 10.5, 47 and 210 mg kg -1 ), in the presence and absence of lime, on: common beans development, Ni phytoavailability, and soil biological characteristics. A greenhouse experiment was conducted using a sample of a Rhodic Hapludox. Rate of 210 mg kg -1 of Ni caused plant death in both the absence and the presence of lime. Grain yield of common beans was higher in treatments with lime addition. However, grain Ni concentration increased with Ni addition, exceeding the maximum admissible value, of 5 mg kg -1 (fresh weight), already at rate of 2.3 mg kg -1 . Lime addition was not enough to reduce grain Ni concentrations to permissible levels for consumption. The addition of high concentrations of Ni decreased soil microbial biomass, and this reduction was accompanied by an increase in the metabolic quocient. The qCO 2 was an adequate indicator of the stress level caused by Ni addition on soil microbial community.

Growth and Micronutrient Concentration in Maize Plants Under Nickel and Lime Applications

“…According to Berton et al (2006), an increase in nickel concentrations up to 2.3 mg kg -1 in soils is sufficient to increase the concentration of this element in beans above 5 mg kg -1 fresh weight, making them unsuitable for human consumption.…”

“…According to Berton et al (2006), it is estimated that, worldwide, 106,000 to 544,000 tons of nickel are added annually to soils, originating from metallurgical activities, the burning of fossil fuels and the addition of sewage sludge and industrial compounds.…”

Microbiological and chemical attributes of a Hapludalf soil with swine manure fertilization

“…The high levels of labile C and low C:N ratio in pig slurries stimulate the soil microbial population, increasing their size and activity. However, organic residues containing potentially toxic chemical elements may negatively affect soil microorganisms (Berton et al, 2006). In this case, the MB-C may be useful for providing rapid information on changes in the soil organic properties.…”

Growth of tropical grasses in Oxisol contaminated by nickel

“…For this, strong acids have been used that are not part of the routine chemical soil analysis for fertility purposes; they do not always extract concentrations of elements correlated with levels absorbed by plants. Correlations between soil Ni concentration extracted by several extractors and the concentration accumulated by some plants have defined the most efficient extractors to predict the phytoavailability of this element (Berton et al, 2006;Chang et al, 2014;Rodak et al, 2015).…”