Chumbo, níquel e zinco em plantas de milho e solos tratados com lodo de esgoto após dezoito anos consecutivos
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Data
2017-11-07
Autores
Ribas, Greiscyléia Togo Côrte
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O esperado aumento na produção do lodo de esgoto e o volume diário de lodo descartado em aterros sanitários reforçam a necessidade do reaproveitamento deste resíduo que pode fornecer nutrientes às plantas ao ser aplicado no solo, tornando-se importante alternativa de disposição, porém a presença de metais pesados limita seu uso. Assim, em duas áreas que receberam lodo de esgoto por 18 anos consecutivos, o objetivo foi avaliar a concentração de Pb, Ni e Zn no solo e plantas de milho após a 18ª aplicação do resíduo. Este experimento ocorreu no ano agrícola 2014/2015 em área de LATOSSOLO VERMELHO Eutroférrico e LATOSSOLO VERMELHO Distrófico, no município de Jaboticabal, SP; com 4 tratamentos (0, 5, 10 e 20 t ha-1 de lodo de esgoto, respectivamente T0, T5, T10 e T20) organizados no delineamento em blocos casualizados com 5 repetições. Foram avaliadas as concentrações pseudototal através do método 3050 B da USEPA e teor disponível através do método Mehlich 1 de Pb, Ni e Zn no solo, acúmulo desses metais na parte aérea das plantas, teor nos grãos e na folha diagnose; estado nutricional, produtividade e massa seca da parte aérea da planta. As concentrações de Pb, Ni e Zn no solo das duas áreas que receberam lodo de esgoto foram superiores aquelas que receberam apenas fertilização mineral convencional, porém no 18º ano de aplicação de lodo, os teores desses metais no solo ainda permanecem abaixo dos níveis estabelecidos para intervenção agrícola, de acordo com a legislação brasileira. Não foram observados na parte aérea das plantas, folhas e grãos de milho teores de Pb, Ni e Zn acima dos limites estabelecidos nas legislações vigentes. Maiores teores de Ni e Zn foram observados nos grãos das plantas cultivadas com a maior dose de lodo de esgoto. Para o estado nutricional, apenas P e B ficaram abaixo do nível crítico estabelecido, os teores de Mg e Mn tiveram efeito dos tratamentos na área do LATOSSOLO VERMELHO Distrófico. O lodo de esgoto com as características discutidas nesse estudo, não interfere na produção de massa seca de parte aérea as plantas, mas provoca aumento da produtividade de grãos com doses de 10 e 20 t ha-1 na área de LATOSSOLO VERMELHO Distrófico. Embora o Pb seja um elemento muito tóxico, não foi detectado nos grãos, Ni e Zn são micronutrientes que podem limitar a aplicação de lodo de esgoto ao solo. O LATOSSOLO VERMELHO Eutroférrico possui maior capacidade de acúmulo dos metais pesados estudados Pb, Ni e Zn, porém as quantidades fitodisponíveis são menores, devidos suas características, em relação ao LATOSSOLO VERMELHO Distrófico.
The expected increase in the production of sewage sludge and the daily volume of sludge discarded in landfills reinforce the need to reuse this residue, which can provide nutrients to the plants when applied to the soil, making it important disposal alternative of heavy metals limits its use. Thus, in two areas that received sewage sludge for 18 consecutive years, the objective was to evaluate the concentration of Pb, Ni and Zn in the soil and corn plants after the 18th application of the residue. This experiment occurred in the agricultural year 2014/2015 in the area of Red Oxisol eutroferric and Red Oxisol distrophic, in the municipality of Jaboticabal, SP; with 4 treatments (0, 5, 10 and 20 t ha-1 of sewage sludge, respectively T0, T5, T10 and T20) organized in a randomized block design with 5 replicates. The pseudototal concentrations were evaluated using the USEPA method 3050 B and content available by the Mehlich 1 method of Pb, Ni and Zn in the soil, accumulation of these metals in the aerial part of the plants, grain content and diagnosis leaf; nutritional status, productivity and dry mass of the aerial part of the maize plant. The concentrations of Pb, Ni and Zn in the soil of the two areas that received sewage sludge were higher than those that only received conventional mineral fertilization, but after the 18th year of sludge application, the levels of these metals in the soil still remain below the established levels for agricultural intervention, in Brazilian legislation. No Pb, Ni and Zn levels were observed in the aerial part of the plants, leaves and corn above the limits established in the current legislation. Higher levels of Ni and Zn were observed in the grains of the plants grown with the highest dose of sewage sludge. For the nutritional status, only P and B were below the established critical level, the Mg and Mn contents had effect of the treatments in the area of the Red Oxisol distrophic. The sewage sludge with the characteristics discussed in this study does not interfere in the production of dry mass of shoot plants, but causes increase of grain yield with doses of 10 and 20 t ha-1 in the area of Red Oxisol distrophic. Although Pb is a very toxic element, was not detected in the grains, Ni and Zn are micronutrients that can limit the application of sewage sludge to soil. The Red Oxisol eutroferric has a greater capacity of accumulation of the studied heavy metals Pb, Ni and Zn, but the phytodisposable amounts are smaller, due to their characteristics, in relation to the Red Oxisol distrophic.
The expected increase in the production of sewage sludge and the daily volume of sludge discarded in landfills reinforce the need to reuse this residue, which can provide nutrients to the plants when applied to the soil, making it important disposal alternative of heavy metals limits its use. Thus, in two areas that received sewage sludge for 18 consecutive years, the objective was to evaluate the concentration of Pb, Ni and Zn in the soil and corn plants after the 18th application of the residue. This experiment occurred in the agricultural year 2014/2015 in the area of Red Oxisol eutroferric and Red Oxisol distrophic, in the municipality of Jaboticabal, SP; with 4 treatments (0, 5, 10 and 20 t ha-1 of sewage sludge, respectively T0, T5, T10 and T20) organized in a randomized block design with 5 replicates. The pseudototal concentrations were evaluated using the USEPA method 3050 B and content available by the Mehlich 1 method of Pb, Ni and Zn in the soil, accumulation of these metals in the aerial part of the plants, grain content and diagnosis leaf; nutritional status, productivity and dry mass of the aerial part of the maize plant. The concentrations of Pb, Ni and Zn in the soil of the two areas that received sewage sludge were higher than those that only received conventional mineral fertilization, but after the 18th year of sludge application, the levels of these metals in the soil still remain below the established levels for agricultural intervention, in Brazilian legislation. No Pb, Ni and Zn levels were observed in the aerial part of the plants, leaves and corn above the limits established in the current legislation. Higher levels of Ni and Zn were observed in the grains of the plants grown with the highest dose of sewage sludge. For the nutritional status, only P and B were below the established critical level, the Mg and Mn contents had effect of the treatments in the area of the Red Oxisol distrophic. The sewage sludge with the characteristics discussed in this study does not interfere in the production of dry mass of shoot plants, but causes increase of grain yield with doses of 10 and 20 t ha-1 in the area of Red Oxisol distrophic. Although Pb is a very toxic element, was not detected in the grains, Ni and Zn are micronutrients that can limit the application of sewage sludge to soil. The Red Oxisol eutroferric has a greater capacity of accumulation of the studied heavy metals Pb, Ni and Zn, but the phytodisposable amounts are smaller, due to their characteristics, in relation to the Red Oxisol distrophic.
Descrição
Palavras-chave
biossólido, latossolo, metal pesado, zea mays L., biosolid, oxisol, heavy metal, zea mays L.