The objectives of this study were to evaluate the combined effects of soil biotic and abiotic factors on the incidence of Fusarium corn stalk rot, during four annual incorporations of two types of sewage sludge into soil in a 5-years field assay under tropical conditions and to predict the effects of these variables on the disease. For each type of sewage sludge, the following treatments were included: control with mineral fertilization recommended for corn; control without fertilization; sewage sludge based on the nitrogen concentration that provided the same amount of nitrogen as in the mineral fertilizer treatment; and sewage sludge that provided two, four and eight times the nitrogen concentration recommended for corn. Increasing dosages of both types of sewage sludge incorporated into soil resulted in increased corn stalk rot incidence, being negatively correlated with corn yield. A global analysis highlighted the effect of the year of the experiment, followed by the sewage sludge dosages. The type of sewage sludge did not affect the disease incidence. A multiple logistic model using a stepwise procedure was fitted based on the selection of a model that included the three explanatory parameters for disease incidence: electrical conductivity, magnesium and Fusarium population. In the selected model, the probability of higher disease incidence increased with an increase of these three explanatory parameters. When the explanatory parameters were compared, electrical conductivity presented a dominant effect and was the main variable to predict the probability distribution curves of Fusarium corn stalk rot, after sewage sludge application into the soil.

Studies on the survival of pathogenic microorganisms in the soil after use of wastewater for fertilization of agricultural crops report the effects of moisture, pH, organic matter, and soil temperature on microorganisms. There are few studies that assess the survival of these microorganisms in the rhizosphere of plants fertilized with wastewater. Thus, the aim of this study was to quantify the number of fecal coliforms and rhizobacteria (fluorescent Pseudomonas spp., Bacillus spp,) in the rhizosphere of winter and summer crops fertilized with wastewater. In the experiment, we used 20 plots, and each plot occupied an area of 200 m². The treatments used in the winter crop consisted of uncultivated plots and single crops of wheat, triticale, black bean, and intercropped black bean/wheat. In the summer season, we used uncultivated plots and single crops of corn, sunflower, bean, and intercropped bean/corn. The experiment was conducted in a randomized block design with five treatments and four replications. Soil samples from the rhizosphere for microbiological analyses were collected at the flowering stage of the crops at a depth of 0.00-0.20 m. Plants stimulated fluorescent Pseudomonas spp. and Bacillus spp. in the rhizosphere, with average scores of 7.9 and 6.9 log CFU g -1 of dry soil, respectively, whereas in bare soil, these scores were 6.7 and 5.8 log CFU g -1 of dry soil for these rhizobacteria groups. However, this stimulating effect was not seen for fecal coliforms, which had an average score of 31.7 × 10 3 MPN g -1 of dry soil in the uncultivated area and 20.0 × 10 3 MPN g -1 of dry soil in crop areas. Overall, the numbers of rhizobacteria colonies in the rhizosphere soil under intercropping were higher than those observed in the rhizosphere soils of single winter and summer crops. Therefore, the presence of plants enhances the development of rhizobacteria and changes the balance among the species of microorganisms in the soil microbial community fertilized with wastewater.

O presente projeto teve como objetivo avaliar a qualidade e os efeitos da aplicação da água residuária resultante do tratamento de esgoto sanitário sobre as propriedades químicas de um Argissolo Vermelho Amarelo Distrófico e o rendimento da biomassa e grãos de aveia branca (Avena sativa L). Efetuou-se a caraterização química da água residuária e, depois, foi aplicada superficialmente no solo doses correspondentes a 0, 30, 60 e 90 m 3 ha -1 em parcelas de 200 m 2 . As doses da água foram comparadas com a adubação mineral recomendada para a cultura da aveia. Os tratamentos foram distribuídos em delineamento experimental em blocos casualizados e com quatro repetições. A água residuária apresentou composição química com qualidade para ser utilizada na agricultura. Os valores no solo de cálcio, CTC, V e pH aumentaram e a acidez potencial diminuiu após aplicação das doses de água residuária. As doses de água residuária proporcionaram incrementos na produção de biomassa e grãos de aveia similar ao obtido com a adubação mineral. Conclui-se que água residuária pode ser utilizada para corrigir a acidez do solo e substituir ou complementar a adubação mineral.Palavras-chave: água residuária, disposição no solo, reuso de água.

RESUMOA aplicação do composto de lodo de esgoto em áreas agrícolas pode promover alterações nos atributos microbianos do solo. Assim, há necessidade de se avaliar o impacto da adição do composto sobre a atividade microbiana do solo. O presente trabalho objetivou avaliar a alteração nos atributos microbianos de um solo fertilizado com diferentes doses de composto de lodo por meio da medida de liberação de CO 2 e a contagem de bactérias e fungos. O experimento foi realizado em condição de laboratório, com jarros respirométricos contendo em seu interior amostras de solo misturadas com composto nas doses de 0; 20; 40; 60 e 80 Mg ha -1 . A liberação de CO 2 do solo foi medida diariamente durante os 28 dias de incubação. Após a incubação, as amostras de solo foram retiradas dos jarros e submetidas à contagem de bactérias e fungos e à determinação da composição química do solo. Os tratamentos correspondentes às doses do composto foram dispostos em delineamento completamente casualizado com quatro repetições. A liberação de CO 2 e o número de bactérias e fungos aumentaram significativamente com as doses do composto devido ao fornecimento de substrato energético e nutrientes proporcionados pelo composto. A medida de liberação de CO 2 indicou que a doses de composto acima de 20 Mg ha -1 ocasionou impactos significativos sobre a atividade microbiana do solo.Palavras-chave: atividade microbiana, bactérias, fungos. Soil microbial attributes treated with composting of sewage sludge ABSTRACTThe use of sludge composting in agricultural areas alters the microbial functions. In this context it is necessary to evaluate the impact of composting addition on microbial activities in the soil. This study evaluated the alteration of microbial attributes of a soil fertilized with sewage sludge compost by measuring the CO 2 release rates and counting bacteria and fungi numbers. This experiment was conducted in laboratory using respirometric jars that contained samples of soil mixed with different doses of compost: 0; 20; 40; 60 and 80 Mg ha -1 , and CO 2 release was quantified daily during the 28 days of incubation when the samples were removed from the jars and bacteria and fungi quantities were counted. The treatments corresponding to each dose of the composting were arranged in completely randomized design with four replications. The CO 2 release and the quantity of bacteria and fungi increased with additional doses of the compound. This occurred as a result of supplying energetic substrate and

Abstract. The objectives of this study were to characterize chemically and quantify the nutrient soil input with vegetable oil industrial treated effluent. For effluent characterization, chemical and microbiological analyses were carried out. The experimental design consisted of randomized blocks with five treatments (T1, mineral fertilization; T2, effluent 0 m 3 ha -1; T3, effluent 11 m 3 ha -1 ; T4, effluent 22 m 3 ha -1 and T5, effluent 33 m 3 ha -1 ) and four replicates. Soil samples were collected (0-20 cm layers) 120 day after effluent application. The applications resulted in the increase of nutrients (P, Ca and Mg) and Na that were added to the soil. The treatment with mineral fertilization and effluent proportion (T1) showed a higher plant growth rate Palavras-chave: effluent, nutrients, sodium, eucalypt, forest, efluente, nutrientes, sódio, eucalipto, floresta. INTRODUÇÃOO reuso agrícola de efluentes de esgotos tratados destaca-se como uma alternativa econômica para disposição ambiental desse resíduo, pois aumenta a fertilidade do solo e fornece nutrientes para as plantas. Constitui também, uma forma de minimizar o impacto causado pelo fósforo e pelo nitrogênio nos efluentes de esgoto, quando lançados em corpos receptores (Asano et al., 1996;. Apesar desses benefícios, a prática não é isenta de riscos, principalmente devido à presença de determinados constituintes característicos do esgoto doméstico, como, por exemplo, o sódio e os organismos patogênicos que são prejudicais ao solo, às plantas e, consequentemente, ao ser humano (Balks et al., 1998; Gomes, et al., 2009).A maioria dos estudos apresenta resultados verificados com hortaliças, grãos, forrageiras e cana de açúcar, sendo raros resultados com culturas de reflorestamento (Faria et al., 2003;Cunha, et al., 2005;Biscaro, et al., 2008;Leal,et al., 2009).Com base no exposto, o presente projeto teve como objetivo avaliar o aporte de nutrientes e sódio e, também, o crescimento de Eucalyptus grandis, após a aplicação do efluente no solo. MATERIAL E MÉTODOSO estudo foi realizado em um Argissolo Vermelho-Amarelo distrófico (Embrapa, 1999) Ambientais e Sustentabilidade, Taubaté, Brasil, 09-11 dezembro 2009, IPABHi, p. 711-716. (doi:10.4136/serhidro.93)

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