Fernando Carvalho Oliveira

Efeitos de aplicações sucessivas de lodo de esgoto em um latossolo amarelo distrófico cultivado com cana-de-açúcar: carbono orgânico, condutividade elétrica, ph e CTC

Repeated sewage sludge application to soils can cause changes in some soil chemical properties. The goal of this paper was to evaluate changes in soil organic carbon content, electric conductivity, pH and CEC after sewage sludge application during two years in a row. The soil used was as a Typic Hapludox and, after the sludge application, was planted with sugarcane. The experiment had five treatments: lime + inorganic fertilization, control and sewage sludge in three levels: 33, 66 and 99 Mg ha-1 (dry weight basis) in the first cultivation year (1996/1997) and 37, 74 and 110 Mg ha-1 in the following year (1997/1998). There was an increase in soil organic carbon content, electric conductivity, pH and CEC values, measured 360 days after the sludge application each year. The decrease in soil organic carbon level in the period was adjusted to a first order model kinetics. Soil organic carbon accumulation was also observed and was due to repeated sludge application. There was no cumulative effect on soil electric conductivity for the second sewage sludge application. This allows to conclude that rainfall played an essential role over ion leaching during that period. Increased electric conductivity could be observed in the lower soil depth. The increase in soil pH, after the second sludge application, was lower than that observed after the first one, what indicated the buffer capacity of the soil and alkalinity of the waste. There was an increase in soil CEC, but it was not related to the sludge level applied or to the second application. The changes in CEC were explained based on changes in pH rather than in organic carbon.

Sewage sludge as nitrogen and phosphorus source for cane-plant and first ratoon crops

O uso do lodo de esgoto na agricultura brasileira foi normatizado pela Resolucao Conama no 375, de 2006. No entanto, faltam pesquisas para adequar as doses complementares de adubos minerais nitrogenado e fosfatado a serem aplicadas em area agricola tratada com lodo. Avaliaram-se os efeitos de doses de lodo de esgoto e de adubos minerais nitrogenado e fosfatado sobre a produtividade e as caracteristicas tecnologicas da cana-planta e da primeira soqueira (efeito residual), em campo. Foram aplicadas quatro doses de lodo (0, 3,6, 7,2 e 10,8 t ha-1, base seca), de N (0, 30, 60 e 90 kg ha-1) e de P2O5 (0, 60, 120 e 180 kg ha-1), em delineamento em blocos casualizados, em esquema fatorial, com duas repeticoes. Para avaliar o efeito residual do lodo, foram aplicados 120 kg ha-1 de N e 140 kg ha-1 de K2O em todas as plotas. A aplicacao de lodo no plantio da cana, combinado ou nao com adubo mineral nitrogenado e, ou, fosfatado, aumentou a produtividade de colmos de 84 a 118 t ha-1, sem alterar a qualidade tecnologica da cana-de-acucar, em relacao a adubacao NPK convencional, que produziu 91 t ha-1 de colmo. O estudo de superficie de resposta para a produtividade de colmo, em solo de baixa fertilidade, permitiu estabelecer sugestao de recomendacao de adubo mineral nitrogenado e fosfatado para implantacao de canavial, em funcao da dose de lodo, bem como concluir que a aplicacao de 10,8 t ha-1 de lodo, ou seja, da dose estabelecida pelo criterio do N, conforme Resolucao Conama no 375, pode: reduzir o uso de N mineral em 100 % e o de P2O5 em 30 %, com aumento de produtividade de colmos em 22 %, em relacao a adubacao NPK convencional, como efeito direto do lodo sobre o cultivo da cana-planta; e aumentar a produtividade de colmos da primeira soqueira em ate 12 % e a de acucar em ate 11 %, como efeito residual do lodo aplicado na cana-planta sobre o cultivo da cana-soca.

Percolação de nitrato em Latossolo Amarelo distrófico afetada pela aplicação de composto de lixo urbano e adubação mineral

The movement of nitrate in soil percolate was evaluated in a field experiment using a Typic Hapludox cultivated with sugarcane and amended with urban compost waste or inorganic fertilizer. The experiment, conducted during the years of 1996/97 and 1997/98, had the following treatments: lime + inorganic fertilization, and control and urban compost waste applied in three levels: 20, 40 and 60 Mg ha-1 (dry weight basis). In the second year (1997/98), the urban compost waste was applied to soil in three levels: 24, 48 and 72 Mg ha-1. The results showed an increased nitrate level in the soil percolate at the 0.3, 0.6 and 0.9 m soil depth as a result of inorganic fertilization and compost waste disposal. Nitrate losses evaluated in the 0-0.9 m soil depth showed pollution potential risks either for the inorganic fertilizer or the compost. In the compost treatments, there was an increase in soil organic N at the soil surface and also in the N-NO3- and N-NH4+ levels at the 0.9-1.2 m soil depth. Annual rates of 24 Mg ha-1 (305 kg ha-1 of total N) did not show evidences of causing any groundwater pollution, according to the values established by the World Health Organization. The risks due to nitrate percolation must be considered when planning rate and frequency of application of this waste to soil, to avoid the possibility of nitrate groundwater pollution. In this case, the soil and soil solution monitoring play fundamental roles in preventing this type of pollution.

Carbono, nitrogênio, fósforo e enxofre em solos tratados com composto de lixo urbano

Foram estudados os efeitos da aplicacao de composto de lixo urbano, proveniente da usina de compostagem Sao Matheus da cidade de Sao Paulo, na dose de 30 g dm-3 (60 t ha-1), na presenca e ausencia de calcario dolomitico e adubos minerais, sobre os teores de carbono orgânico, de nitrogenio total e de fosforo e enxofre disponiveis de 21 solos acidos e cinco solos alcalinos, onde o calcario foi substituido por gesso. O experimento foi realizado em condicoes de casa de vegetacao com os solos nas parcelas em blocos ao acaso, com tres repeticoes e os tratamentos em subparcelas. O acumulo de materia orgânica, em virtude da aplicacao do composto, foi evidente em solos com teores iniciais de carbono orgânico > 12 g dm-3 e de nitrogenio > 1,3 g dm-3, porem com relacao C/N < 12. Nos demais solos, o acumulo foi decorrente da interacao entre a estabilidade da materia orgânica do composto, da materia orgânica nativa e as propriedades fisicas e quimicas dos solos. A aplicacao do composto aumentou os teores de nitrogenio total e de enxofre disponivel em todos os solos, porem o fosforo disponivel somente foi aumentado nos solos acidos. A aplicacao do composto de lixo urbano como fertilizante orgânico e viavel, porem seus efeitos sobre as propriedades quimicas do solo devem ser monitorados.

Movimentação de metais pesados em Latossolo adubado com composto de lixo urbano

From 1996 to 1998, a field experiment was carried out to study the effects of successive application of a municipal solid waste compost on the movement of Cd, Cr, Cu, Ni, Pb, and Zn through the profile of a Yellow Latossol (Typic Hapludox) cropped with sugarcane. The compost was applied at rates of 20, 40 and 60 Mg ha -1 (dry base) in the first year, and of 24, 48 and 72 Mg ha -1 in the second year, respectively, plus a control treatment. The results demonstrated that there was no movement of Cd, Cr, Cu, Ni, and Pb through the profile of this acid soil. Nevertheless, Zn mobility was verified at the end of the second year, when content of Zn increased from 0.4 to 0.6 m layer.

FITODISPONIBILIDADE E TEORES DE METAIS PESADOS EM UM LATOSSOLO AMARELO DISTRÓFICO E EM PLANTAS DE CANA-DE-AÇÚCAR ADUBADAS COM COMPOSTO DE LIXO URBANO

Heavy metal components in solid urban waste composts have been one of the main causes of concern in relation to its use on agricultural soils. On this background, a field experiment was carried out to study the effects of successive compost application on Cd, Cr, Cu, Ni, Pb, and Zn contents in a Typic Hapludox, in sugarcane plants, as well as on the phytoavailability of these metals as assessed by chemical extractors (DTPA, 0,1 mol L-1 HCl and Mehlich-3). The compost was applied at rates of 0, 20, 40 and 60 Mg ha-1 in 1996/97, and of 0, 24, 48 and 72 Mg ha-1 in 1997/98. The total Cu contents increased, compared with the control soil, and varied between 12 and 25 % in the first and 27 and 88 % in the second year of cropping. For Zn, these values varied from 12 to 72 % and from 72 to 156 % in the first and second years, respectively, while Cr varied from 12 to 25 % in the second year. Cd, Ni, and Pb concentrations in the soil, and Cd, Cr, Ni and Pb in sugarcane leaves, stalks and juice were also below the determination limit. Cu and Zn contents in plant samples were not affected by the compost application. The chemical extractors did not differ among each other and were not able to assess, properly, metal phytoavailability for sugarcane, properly, due to the low concentrations in soil and plant samples.

Lodo de esgoto na recuperação de áreas degradadas: efeito nas características físicas do solo

A recuperacao de areas degradadas e um processo lento e requer a adicao de residuos orgânicos como condicionador das propriedades fisicas do solo. O lodo de esgoto apresenta elevados teores de materia orgânica (MO) e nutrientes e, portanto, tem alto potencial para utilizacao nessas areas. O objetivo deste trabalho foi verificar o efeito da adicao de lodo de esgoto na recuperacao das caracteristicas fisicas de um solo degradado (Neossolo Quartzarenico) plantado com especies nativas da Mata Atlântica, na Fazenda Entre-Rios, pertencente a Cia. Suzano Bahia Sul de Papel e Celulose, na regiao de Itatinga-SP. O experimento foi conduzido em blocos casualizados com quatro repeticoes. Os tratamentos foram constituidos por seis doses de lodo de esgoto (0, 2,5, 5, 10, 15 e 20 t ha-1), mais um que recebeu a adubacao quimica. A aplicacao de lodo de esgoto, para recuperacao de areas degradadas, aumentou os agregados do solo conforme o aumento das doses de lodo, ate 12 meses apos sua aplicacao. As porosidades (macro, micro e total) do solo foram aumentadas com as maiores doses de lodo de esgoto ate seis meses apos sua aplicacao; apenas a microporosidade foi aumentada ate 12 meses apos a aplicacao. Houve aumento da umidade do solo em funcao do aumento das doses de lodo no solo ate seis meses apos a aplicacao.

Doses de lodo de esgoto compostado em produção de tapete de grama esmeralda imperial

The efficiency of nitrogen fertilization for sod production can be increased by using slow-release sources such as sewage sludge compost, which, due to its characteristics can be a substitute of part or all inorganic fertilization for grass. No results were found for the use of sludge compost in sod production in Brazil. This study evaluated the effect of rates of sewage sludge compost on the production of zoysiagrass. Treatments consisted of five rates of composted sewage sludge compost (0, 12, 24, 36 and 48 Mg ha-1, on a dry basis), plus a treatment of inorganic fertilization (300 kg ha-1 N, 80 kg ha-1 P2O5, and 200 kg ha-1 K2O). The results indicated different mineralization rates of the organic compounds present in the sludge; 120 days after sludge application, more Mg (100 %), K (90 %) and N (67 %) has been released than S (57 %), P (40 %) and Ca (31 %). The use of composted sewage sludge for zoysiagrass adequately supplied nutrients when applied to the soil surface at rates more than 36 Mg ha-1. After sod cutting, the rates of sewage sludge compost provided a linear increase in potential soil acidity, soil contents of OM, P, S, Fe, Cu, Mn, Zn, Cu and Ni, and linear decrease in pH, soil concentration of Ca and Mg and base saturation. Compost rates, increasing from 0 to 48 Mg ha-1, reduced the sod mass, reaching values of 4.0 kg/sod at the highest rate. High compost doses (36 and 48 Mg ha-1, respectively) also induced the highest resistance, with values in the order of 35 and 33 kgf.

Bioevaluation of the nutritional status of rice (Oriza sativa L. cv. IAC-165) and bean (Phaseolus vulgaris L. cv. carioca) plants using 15N and 32P

Rice and bean plants were grown in nutrient solution in the presence of three levels of N, P and K. The method of the bioevaluation of the nutricional status, in which excised roots are allowed to take up tagged elements, in this case 15N and 32P, was compared with foliar analysis. Two main conclusions were drawn: 1) the bioevaluation proved to be an useful and rapid procedure for the diagnosis of the nutricional status of both species, since there was a significant negative correlation between absorption of N and P and dry matter yield; 2) the uptake of the tagged ions with either element by the roots of plants grown under deficient levels of N and P in the nutrient solution was inversely proportional to the leaf concentration of both nutrients.

Persistence of Ascaris spp. Ova in Tropical Soil Cultivated with Eucalyptus and Fertilized with Municipal Biosolids

In many countries, the main reason for severely restricting or outright banning the land application of class B biosolids is the lack of risk assessment for adverse human health impacts. Among pathogens that are not often studied are helminth ova, including that of the spp. Almost all of the knowledge about the persistence of spp. ova in soils fertilized with biosolids is based on studies developed in North America, Europe, and Asia. These studies have almost always been conducted under temperate climate conditions, which may cause erroneous interpretations when the conclusions are extrapolated to tropical regions such as those found in Brazil. This team evaluated the persistence of viable spp. ova in a sandy Quartzipsamment tropical soil, previously planted with × hybrid () and fertilized with biosolids, over a 52-wk period. During the reporting period, the average temperature of soil and biosolids fluctuated between 15 and 30°C, and the average moisture of biosolids fluctuated between 60 and 90%. The estimated persistence time of viable spp. ova after land application was estimated at close to 7 wk, indicating that ova may not be viable for as long as it has been shown to be in studies of more temperate areas. The relationship of temperature with persistence of viable spp. ova in a tropical soil was stronger than moisture content, suggesting that temperature substantially contributed to their nonviability over the course of the experiment.