ABSTRACT This study aimed to evaluate the total contents of As, Cu and Zn in the profile of a Haplic Cambisol cultivated with crambe and corn and fertilized with sanitary sewage sludge and to compare them with those obtained in other forms of fertilization, as well as the content of metals in the grain of these crops. Two experiments were carried out in the field, one with maize cultivation and another with crambe, both were delineated as randomized blocks with four treatments and six replicates, which were: without fertilization, fertilization with sewage sludge dewatered and dried in the sun, with dry sewage sludge and with mineral fertilizers. At the end of the experiments soil samples were collected at 15, 50, 100, 150 and 200 cm depth for analysis of the total contents of As, Cu and Zn, as well as the grain of the crops. No differences were observed among the treatments. The total contents of As, Cu and Zn in the soil in both experiments and in the corn grains are below the limits of prevention and the maximum limit in grains established by the Brazilian resolutions. In relation to depth, the metal contents in the samples collected from the soil submitted to the fertilization treatments were similar to those quantified in the plots that did not received fertilization, but there was accumulation of Cu and Zn in the upper layers of the soil that received fertilization.

RESUMONeste trabalho objetivou-se avaliar o efeito residual da adubação com lodo de esgoto sobre a produção e nutrição do girassol em segundo cultivo. O experimento foi realizado no período de abril a agosto de 2012. Os tratamentos corresponderam a quatro doses de lodo de esgoto (0; 10; 20 e 30 t ha-1, em base seca) aplicadas no primeiro cultivo de girassol, distribuídas no delineamento em blocos casualizados, com seis repetições. O diâmetro do caule, a altura da planta, o diâmetro do capítulo e a produtividade do girassol aumentaram com o incremento de lodo de esgoto sendo os valores máximos observados na dose de 30 t ha-1. Os teores de cálcio e magnésio no solo, o pH, a soma de bases, a capacidade de troca catiônica efetiva e potencial e a percentagem de saturação de bases aumentaram enquanto a acidez potencial e os teores manganês e ferro na folha diminuíram com o incremento das doses residuais de lodo de esgoto. Houve redução na produtividade e nas características de crescimento do girassol no segundo cultivo, recomendando-se novas adubações com lodo, a cada plantio.

ABSTRACTThis study aimed to evaluate the residual effect of sewage sludge fertilization on yield and nutrition of sunflower in its second cycle. The experiment was carried out from April to August 2012. The treatments consisted of four doses of sewage sludge (0, 10, 20 and 30 t ha-1, dry basis) applied in the first cycle of sunflower, distributed in a randomized block design, with six replicates. Sunflower stem diameter, plant height, capitulum diameter and yield increased with the increment in sewage sludge doses, with maximum values observed with the dose of 30 t ha-1. The contents of calcium and magnesium in the soil, pH, sum of bases, effective and potential cation exchange capacity and base saturation increased, while potential acidity and the contents of manganese and iron in the leaves decreased, with the increment in the residual doses of sewage sludge. There was a reduction in yield and growth characteristics of sunflower in the second cycle; thus, additional fertilization with sewage sludge is recommended in each new cycle.

O biossólido é excelente fonte de nutrientes de plantas; entretanto, pode contaminar o solo. O trabalho teve por objetivo avaliar a influência da adubação com composto de lodo de esgoto e silicato de cálcio e magnésio, nos teores de metais pesados no solo e em plantas de mamona. O experimento foi conduzido no Instituto de Ciências Agrárias da UFMG em Montes Claros, MG, no período de junho a dezembro de 2010. O cultivo foi realizado em área de Cambissolo Háplico utilizando-se a mamona (Ricinus communis L.) variedade BRS Energia. O delineamento foi em blocos casualizados em arranjo fatorial 2 x 4, com 3 repetições, sendo 2 doses de silicato de cálcio e magnésio (0 e 1 t ha-1) e 4 doses de composto de lodo de esgoto (0; 23,81; 47,62 e 71,43 t ha-1, em base seca). Não houve interação entre as doses de silicato de cálcio e composto de lodo de esgoto, bem como o silicato de cálcio e magnésio não influenciou os teores de metais pesados no solo e na planta. No solo os teores de Zn e Cu aumentaram com o incremento das doses de composto de lodo de esgoto sendo que Ni, Pb, Cd e Cr não foram influenciados pela aplicação deste resíduo. Na planta com aumento das doses de composto de lodo de esgoto houve aumento apenas nos teores de Cd e Pb.

Biosolids are an excellent source of plant nutrients; however, it can contaminate the soil. The aim of this work was to assess the influence of the fertilization with sewage sludge compost and calcium and magnesium silicate on the levels of heavy metals in soil and in castor plants. The experiment was conducted at the Institute of Agrarian Sciences (ICA) of UFMG in Montes Claros, MG, from June to December 2010. The cultivation was carried out in area of Inceptisol, using the castor bean plant (Ricinus communis L.) variety BRS energy. The experiment was conducted in randomized blocks, in factorial scheme 4 x 2, with 3 replications consisting of 2 doses of calcium and magnesium silicate (0 and 1 t ha-1) and 4 doses of sewage sludge compost (0; 23.81; 47.62 and 71.43 t ha-1, on dry weight basis). There was no interaction between the doses of calcium silicate and sewage sludge compost, as well as, the calcium and magnesium silicate did not influence the levels of heavy metals in soil and plant. In soil, the levels of Zn and Cu increased with the increase in dose of sewage sludge compost, however Ni, Pb, Cd and Cr were not influenced by the application of residue. In the plant, increasing dose of sewage sludge compost increased only the Cd and Pb levels.

Objetivou-se, com este trabalho, avaliar os teores de metais pesados no solo e em plantas de girassol adubadas com doses de lodo de esgoto. O experimento foi desenvolvido em Cambissolo Háplico, no período de abril a setembro de 2011. Os tratamentos, distribuídos no delineamento em blocos casualizados, com quatro repetições, corresponderam a um tratamento com adubação química e cinco doses de lodo de esgoto aplicadas com base nos teores de N do resíduo e na exigência de N do girassol (0; 4,84; 9,68; 19,36 e 29,04 t ha-1, em base seca). Os teores de Zn no solo e na planta foram maiores nos tratamentos com a aplicação de lodo de esgoto quando comparados com a adubação química. A aplicação de lodo de esgoto resulta em aumento nos teores de Cu, Ni e Pb no solo e não apresenta influência sobre os teores de Zn, Fe, Mn, B, Cd e Cr neste substrato. Por outro lado, na planta, com o aumento da dose de lodo de esgoto, houve aumento dos teores de Zn, Cu e Mn e redução do teor de Pb.

The aim of this study was to evaluate the contents of heavy metals in soil and in sunflower plants fertilized with sewage sludge. The experiment was conducted in Cambisol, during the period of April to September 2011. The treatments, distributed in a randomized block design with four replicates, corresponding to a treatment with chemical fertilization and five doses of sewage sludge, based on the N content in residue and N requirement of sunflower (0, 4.84; 9.68; 19.36 and 29.04 t ha-1, on dry weight basis). Zn levels in soil and plant were higher under the application of sewage sludge compared to treatment of chemical fertilizer. The application of sewage sludge increases levels of Cu, Ni and Pb in soil and has no influence on the levels of Zn, Fe, Mn, B, Cd and Crin this substrate. On the other hand, at the plant, with increased of sewage sludge dose, it was observed an increase in the levels of Zn, Cu, and Mn and reduction on Pb content.

Objetivou-se, com este trabalho, avaliar o efeito residual da adubação com composto de lodo de esgoto e fosfato natural de Gafsa sobre os teores de nutrientes no solo, na planta e na produtividade do milho. O trabalho foi realizado em Cambissolo Háplico. Os tratamentos, em esquema fatorial 2 x 4, corresponderam a 2 doses de fosfato de Gafsa (0 e 90 kg ha-1 de P2O5) e 4 doses de composto de lodo de esgoto (0; 25; 50 e 75 t ha-1, em base seca). O delineamento experimental utilizado foi em blocos casualizados, com 3 repetições. Em geral, a produtividade e os teores de nutrientes no solo e na planta no segundo cultivo sucessivo de milho não foram influenciados pela adubação com fosfato natural reativo. Entretanto, a produtividade de milho e os teores de nutrientes no solo e nas folhas de milho aumentaram com a dose de composto de lodo de esgoto ao solo, sendo a dose de 75 Mg ha-1, a de maior efeito residual. A produtividade do milho é menor no segundo cultivo sucessivo em razão do empobrecimento do solo em fósforo e potássio, recomendando-se novas adubações com lodo de esgoto, a cada cultivo realizado.

The aim of this study was to evaluate the residual effect of fertilization with sewage sludge compost and rock phosphate on the chemical properties of the soil, nutrient content in plant and corn yield. The study was conducted on Haplic Cambisol. The treatments, in a factorial 2 x 4, corresponded to two doses of Gafsa phosphate (0 and 90 kg P2O5 ha-1) and four doses of sewage sludge compost (0, 25, 50 and 75 Mg ha-1 dry weight basis). The experimental design was in randomized blocks with three replications. In general, the corn yield and content of macronutrients in soil and plant on the second crop of corn were not influenced by the residual effects of fertilization with phosphate rock. However, corn yield and nutrient content in soil and leaves increased with the dose of sewage sludge compost applied to the soil, and the dose of 75 Mg ha-1 was the one with the highest residual effect. The yield of corn was lower in the second successive cultivation, due to the impoverishment of the soil phosphorus and potassium, recommending new fertilization with sewage sludge in every cultivation.