Leonardo Duarte Batista da Silva

Características da chuva e perdas por erosão sob diferentes práticas de manejo do solo

This study was carried out in order to evaluate the relation between erosivity index and the rainfall pattern associated with different kinds of soil preparation and cover with erosion losses in a Red Yellow Argisol. The experiment was conducted in five soil loss experimental plots of 3.5 x 22.0 m, with the following treatments: conventional tillage (plowing plus disking) in contour lines and sowing the velvet bean (Mucuna pruriens), sun hemp (Crotalaria juncea) and corn (Zea mays L.); conventional tillage (plowing plus disking) in slope line and sowing of corn, conventional tillage (plowing plus disking) in slope line and without soil cover. The results showed that soil loss was more affected by different treatments than water loss; the treatments sun hemp and corn sowed in slope line were those that presented, respectively, the smaller and the larger soil and water losses; and the precipitation events characterized as advanced, intermediate and delayed patterns were responsible for 62.6, 11.8 and 25.6% of the water losses and for 35.1, 6.6 and 58.3% of the soil losses, respectively.

Evapotranspiração do capim Tanzânia obtida pelo método de razão de Bowen e lisímetro de pesagem

Pasture irrigation in Brazil presented a large increasing in the recent years; however irrigation management practices have been done irrationally due to a lack of research on water use by pastures. The objectives of this research were to determine evapotranspiration of Guinea grass (Panicum maximum Jacq.) by measurements of a weighing lysimeter; to apply the energy balance method to estimate evapotranspiration of Guinea grass by means of an automated Bowen ratio system; and to compare the measured and the estimated values of evapotranspiration. The experiment was carried out in Piracicaba - SP, Brazil, between July 21, 2000 and July 15, 2001. The average evapotranspiration of Guinea grass was 4.13 mm day-1 by the energy balance method and 4.34 mm day-1 by the weighing lysimeter. It was concluded that the estimated evapotranspiration obtained by the automated Bowen ratio system can be influenced by advection and by long duration rainfalls. Despite of these constraints, there was a reasonable correlation with the measurements of a weighing lysimeter.

Distribuição, probabilidade de ocorrência e período de retorno dos índices de erosividade EI30 e KE>25 em Seropédica - RJ

O presente trabalho foi desenvolvido com o objetivo de estudar as caracteristicas da erosividade da chuva em Seropedica (RJ), quanto a sua distribuicao, probabilidade de ocorrencia e periodo de retorno. Para isso, foi utilizada uma serie mensal de dados pluviometricos referente ao periodo de 1973 a 2002 e, com o auxilio de modelos ajustados para a regiao, foi possivel obter os indices mensais e anuais de erosividade EI30 e KE>25. Com base nos resultados obtidos, foi possivel concluir que: a) os valores medios anuais de EI30 e de KE>25 foram de 5.960,4 MJ mm ha-1 h-1 e de 99,2 MJ ha-1, respectivamente, e estao associados a periodos de retorno de 1,97 ano, com uma probabilidade de ocorrencia de 50,82%; e b) valores anuais de EI30 da ordem de 5.995; 7.262; 7.684; 7.895; 8.022 e 8.064 MJ mm ha-1 h-1 e de KE>25 da ordem de 99,8; 122,7; 130,3; 134,1; 136,4 e 137,1 MJ ha-1, sao esperados, em media, uma vez a cada 2; 5; 10; 20; 50 e 100 anos, respectivamente.

Avaliação do efeito do extrato de sementes de Moringa oleifera Lam na eficiência de filtros orgânicos no tratamento de águas residuárias de bovinocultura de leite

Objetivou-se avaliar o efeito do extrato de Moringa oleifera Lam na remocao de solidos totais (ST), solidos em suspensao totais (SST) e demanda quimica de oxigenio (DQO), em distintos meios filtrantes, no tratamento da agua residuaria de bovinocultura de leite (ARB). O extrato de sementes de moringa foi obtido triturando-se 50 g de sementes em um litro de agua destilada e, apos passar a solucao em papel de filtro quantitativo de 25 µm, foram adicionados 60 mL do extrato a agua residuaria de bovinocultura, antes do processo de filtracao em filtros orgânicos constituidos por fino de carvao, folhas de bambu, folhas de eucalipto, ramos de gliricidia e serragem de madeira. Seguiu-se o delineamento experimental inteiramente aleatorizado, adotando um esquema fatorial de 5 x 2. Aliquotas do efluente filtrado foram coletadas, e determinaram-se as concentracoes de solidos totais (ST), solidos em suspensao totais (SST) e demanda quimica de oxigenio (DQO). Verificou-se que o aumento na eficiencia de remocao de solidos totais e DQO pode ser atribuido ao poder coagulante do extrato de sementes de moringa, sendo que o meio filtrante com folhas de bambu apresentou melhor desempenho, demonstrando potencial de utilizacao como material filtrante alternativo no tratamento primario de ARB.

Proposta de metodologia para zoneamento ambiental de plantio de eucalipto

The objective of this work was to develop a method for environmental zoning of eucalyptus plantations, to identify areas where eucalyptus planting could be developed, and to determine suitability of such areas. The study area was the County of Vassouras, in the State of Rio de Janeiro, considering physical data, environmental legislation, urban areas, and the municipal land use plan. The areas for permanent preservation, as well as the conservation units and areas for industrial expansion, as defined in the county land use plan, plus areas nearby the city were considered restricted for the planting of eucalyptus trees. Vassouras is 552 km² large. Approximately 144 km² are suitable eucalyptus planting, of which 97% are now used for pastures. Approximately 50% of the area suitable for eucalyptus is of average suitability, whereas the class of highest suitability occupies about 30%. The less suitable areas correspond to 20% of the remaining 144 km 2 .

Mathematical modeling of COD removal via the combined treatment of domestic wastewater and landfill leachate based on the PACT process

The experiments performed in this study consisted of 16 batch reactors fed different mixtures of landfill leachate combined with synthetic wastewater treated using the Powdered Activated Carbon Treatment (PACT) process. The objective was to measure the COD mass removal per liter each day for each reactor using two models: the first model combined the variables PAC concentration (0 g·L−1, 2 g·L−1, 4 g·L−1, and 6 g·L−1) and leachate rate in the wastewater (0%, 2%, 5%, and 10%), and the second model combined the PAC concentration and the influent COD. The Response Surface Methodology with Central Composite Design was used to describe the response surface of both models considered in this study. Domestic wastewater was produced under controlled conditions in the laboratory where the experiments were performed. The results indicated that the PAC effect was null when the influent did not contain leachate; however, as the concentration of leachate applied to the mixture was increased, the addition of a higher PAC concentration resulted in a better COD mass removal in the reactors. The adjusted R2 values of the two models were greater than 0.95, and the predicted R2 values were greater than 0.93. The models may be useful for wastewater treatment companies to calculate PAC requirements in order to meet COD mass removal objectives in combined treatment.

CARACTERÍSTICAS FÍSICO-QUÍMICAS, CAPACIDADE ANTIOXIDANTE E COMPOSTOS FENÓLICOS TOTAIS DE TOMATES FERTIRRIGADOS COM DIFERENTES DOSES DE NITROGÊNIO

The objective of this work was to evaluate the physicochemical and microbiological characteristics, antioxidant capacity and phenolic compounds of organic cherry tomatoes grown under fertigation with organic dairy cattle wastewater (DCW) with different nitrogen rates. Tomato plants, grown in an agroecological farm in Seropédica, State of Rio de Janeiro, Brazil, were subjected to four different nitrogen rates (T1=0, T2=50, T3=100 and T4=150% of N). The moisture, lipids, ashes, protein and total fiber contents, soluble solids (oBrix), reducing and total sugars (%), pH and total titratable acidity (mg NaOH per 100 g) were evaluated. The total phenolic content (TPC) and the antioxidant capacity was determined by the DPPH and FRAP methods. The different nitrogen rates (%N) affected the pH, protein and soluble solids contents. The increase in %N increased the antioxidant capacities, according to the DPPH assay, and TPC. On the other hand, the tomatoes under fertigation with the highest %N presented lower antioxidant capacities according to the FRAP assay. The fertigation did not affect the microbiological characteristics of the tomatoes, which presented fecal coliforms count <3 NMP g and absence of Salmonella in 25 g.

MONITORAMENTO DA CONDUTIVIDADE ELÉTRICA E PH DA SOLUÇÃO DO SOLO SOB DIFERENTES DOSES DE APLICAÇÃO DE VINHAÇA - DOI: 10.13083/1414-3984/reveng.v23n6p552-561

The objective of this study was to evaluate the electrical conductivity (EC) and pH of soil solution cultivated with Vitoria pineapple and fertilized with stillage to supply 0, 50, 75, 100 and 125% of the potassium recommendation for this culture, obtaining treatments: T1 – 0 m³ ha-¹; T2 – 231 m³ ha-¹; T3 – 347 m³ ha-¹; T4 – 462 m³ ha-¹; T5 – 578 m³ ha-¹. The experiment was conducted in a greenhouse at the Department of Biosystems Engineering ESALQ/USP. The planting was conducted in trenches open at ground level fully lined with canvas and filled with soil classified as Oxisol. The application of stillage were performed fortnightly through fertigation system using drip irrigation. Extractors were installed at depths of 0,20 m and 0,40 m for extraction of the solution, vacuum was applied at the tension of 60kKPa two hours after the fertigation. The solution was collected 30, 120, 210 e 270 days after starts of treatments. It was found that treatments with stillage application showed the highest EC in the soil surface layers. The pH, otherwise, decrease with the increment on the vinasse levels.

Caracterização do Aspersor “MIDI” em Diferentes Alturas do Pino Dispersor

Objetivou-se por meio do presente estudo verificar o perfil de distribuicao e o coeficiente de uniformidade em testes de laboratorio para aspersores de impacto de media vazao, em duas posicoes distintas do pino dispersor. O experimento foi conduzido no Laboratorio de Irrigacao do Departamento de Engenharia da Universidade Federal Rural do Rio de Janeiro em Seropedica, RJ. Fora empregado o aspersor FABRIMAR MIDI 360, com a combinacao de bocais 7,2 mm com bocal cego (0 mm) e 6,6 mm (bocal principal) com 3,6 mm (bocal secundario) na pressao de 30 mca e com pino dispersor de 6,0 e 9,0 mm. As melhores medias de coeficiente de uniformidade foram obtidas empregando os bocais duplos com destaque para o com pino de 9 mm, onde o mesmo e indicado ate o espacamento de 18x18 metros para sobreposicao retangular e triangular. Na combinacao 7,2x0 mm obteve-se desempenho satisfatorio ate o espacamento de 15x18 m na sobreposicao retangular e 12x18 m na disposicao triangular. Na analise do perfil de distribuicao observou-se maiores volumes de agua entre as distâncias de 0 a 5,5 m com decrescimo nas distâncias seguintes chegando a baixas precipitacoes nos dois metros finais no ensaio com bocais duplos. Com o bocal cego apenas o primeiro metro apresenta volume de agua discrepante, mantendo valores proximos da media ate 12 metros quando a precipitacao se torna baixa. Os ensaios obtiveram raios efetivamente molhados de 16,5 metros para pino de 6 mm e com bocal cego e 16 m para pino de 9 mm.