Pedro Alexandre Varella Escosteguy

Basalto moído como fonte de nutrientes

Basalt rocks are one of the most common parent materials of large areas of soil in southern Brazil. Several major plant nutrients are present in its composition. The objective of this study was to evaluate the effect of the addition of increased rates of ground basalt rock on the nutrient availability of soil, during three periods of incubation. The rocks tested were a microcrystalline and an olivine-basalt. The rates of basalt rock, corresponding to 0, 5, 10, 25, 50 e 100 t ha-1, basalt were incubated in a Dark Red Latosol and a Red Yellow Podzolic soil. The experiment was carried out under greenhouse conditions at the Agronomy School of Federal University of Rio Grande do Sul. After 30, 150 and 300 days of incubation, the contents of K, Ca, Mg, pH, H + Al, P and CEC of the incubated soils were determined. The different rates tested caused an increase in these variables. However, the increases observed were small, except for P, the value of which may have been overestimated by the extractor used. The release of these elements to the soil varied with incubation period, but not with rock type, with the exception of the concentrations of Ca and P, which were higher for the olivine-basalt. The small release of nutrients from the rocks indicates that these materials cannot be used as the major source of plant nutrients.

Dispersão de argila em microagregados de solo incubado com calcário

Soil compaction limits grain yields. Among others factors, soil amendment with agricultural lime can contribute to micro-aggregate dispersion and the formation of compacted layers. The objective of this study was to evaluate the effect of lime on soil physical attributes related to soil compaction. The experiment was carried out in PVC columns, in a glass house, during 18 months. Sterilized and non-sterilized samples of a dystrophic Red Latosol (Hapludox) were incubated with 0, 1.9, 3.8, 5.7, 7.6 and 15.2 Mg ha-1. After the incubation period, the micro and macro porosity, soil density, clay dispersion, hydraulic conductivity and concentration of exchangeable Al, Ca and Mg and soil organic matter were evaluated. Soil density, clay dispersion, pH and Ca and Mg concentration increased with lime application, while macro porosity, hydraulic conductivity, soil organic matter, and Al decreased. The increase of pH and hydraulic conductivity were higher in the sterilized soil. Liming effects were more evident at a rate of 3.8 Mg ha-1. Soil sterilization increased the pH value and decreased the organic matter content and Ca, besides the hydraulic conductivity. Micro- aggregate dispersion in limed soils can, at least partially, contribute to soil compaction.

RETENÇÃO DE METAIS EM SOLO DA ANTIGA ÁREA DE DISPOSIÇÃO DE RESÍDUOS SÓLIDOS URBANOS DE PASSO FUNDO - RS

A crescente contaminacao de solos e aguas subterrâneas pelos residuos solidos produzidos diariamente nas cidades ascende a necessidade de estudos que elaborem diagnosticos capazes de determinar a retencao desses contaminantes no solo. Este trabalho teve como objetivo a caracterizacao de metais no solo e a investigacao da capacidade de retencao de metais em um solo de uma antiga area de disposicao de residuos solidos urbanos na cidade de Passo Fundo, RS. A caracterizacao dos metais foi realizada atraves do metodo de extracao por digestao e analise em espectrofotometro de absorcao atomica. Dois ensaios de coluna foram realizados para simular o fluxo dos contaminantes por um solo original e nao-contaminado da area, sobre o qual foi realizada disposicao do lixo. Os metais analisados foram: Cromo, Zinco, Cobre e Manganes. Um lixiviado artificial, com concentracoes de metais inseridas, foi percolado pelo solo. A retencao de metais no solo original do aterro foi relevante, sendo maior para os metais Cobre, Cromo e Zinco. Apenas o Manganes atingiu o limite de retencao. Portanto, o solo natural da area possui alta capacidade de remediar estes metais. Palavras-chave: residuos solidos; retencao; ensaio de coluna. ABSTRACT Metals retention in soil of ancient area of disposal of urban solid waste in Passo Fundo – RS. The crescent soil contamination by urban solid waste (USW) denotes the necessity to find a solution to determine the soils attenuation capacity. The aim of this paper is the characterization of metal soil and metals natural attenuation capacity in a soil from one ancient disposal site of USW in Passo Fundo city, located in the south of Brazil. The characterization of metals was realized using the method of extraction by digestion and analysis in atomic absorption spectrometer. Two column tests were carried out to stimulate the flux of contaminants by na original and non-contaminated soil of the area. The metals analyzed in this work were: Chromium, Zinc, Copper and Manganese. An artificial leaching, with concentrations of metals, was used in soil percolation. The metals attenuation in the soil was relevant and it was higher for Copper, Chromium, and Zinc. Only Manganese reached the limit of attenuation. Thus, the natural soil has high capacity to mitigate these metals. Key words: solid waste, attenuation, columns test

Dry matter production and nitrogen use efficiency of giant missionary grass in response to pig slurry application

This study assessed the effect of successive applications of pig slurry on the dry matter (DM) production and the nitrogen use efficiency of giant missionary grass along two years. A total of 55, 110, 165, 220 and 275 m3 of pig slurry/ha/year were applied in order to supply 100, 200, 300, 400 and 500 kg of total N/ha/year, respectively. These treatments were compared with the ammonium nitrate (200 kg of N/ha/year) source of N and with a control (no nitrogen application). Annually, nitrogen was applied in four divided doses, after the cutting of forage grasses, which takes place five times a year. The total DM yield did not differ between years and increased linearly as a function of pig slurry application, ranging from 2,698 kg of DM/ha/year (control) to 11,371 kg of DM/ha/year (275 m3 of pig slurry/ha/year). There was an increment of 32.3 kg of DM/m3 of pig slurry/ha or 17.7 kg of DM/kg of N/ha. The highest average daily DM accumulation rate (66.8 kg of DM/ha/day) was achieved with the highest pig slurry rate, from February/2007 to April/2008. Nitrogen use efficiency did not differ across pig slurry rates (19.0 kg of DM/kg of N), but it was lower than that obtained with ammonium nitrate (30.3 kg of DM/kg of N). The efficiency index of pig slurry ranged from 0.52 to 0.72.

Composição gravimétrica de resíduos sólidos aterrados

The gravimetric composition of solid waste (SW) landfill is basic information for environmental monitoring and projects evaluation. The lack of standard procedures for sampling, the inherent heterogeneity of SW and the different disposal techniques of such wastes or type of landfill, among other factors, have imposed certain limitations to obtain data about landfill gravimetric composition. The objective of this work was to evaluate the difference between the gravimetric composition of SW collected from an open dump and from a controlled landfill and to evaluate if this composition changes with depth of sampling. There was little difference between the SW collected in the two types of landfills. In the controlled landfill pasted mass (41,2 %) was the major component, while in the open dump the plastic film (35,0 %) was the most common material. The SW composition did not change with the sampling depth.

Quality of poultry manure submitted to two types of composting treatments

Neste trabalho se avaliou a qualidade de compostos de esterco de ave poedeira produzidos em pilhas de compostagem e se testaram os seguintes tratamentos: 1) sem gesso e sem revolvimento; 2) com gesso e sem revolvimento; 3) sem gesso e com revolvimento e 4) com gesso e com revolvimento. Para avaliar a qualidade dos compostos foram considerados os padroes do Ministerio de Agricultura, Pecuaria e Abastecimento (MAPA), estabelecidos para ovos e larvas de helmintos, Salmonella sp, coliformes totais e fecais, Cd, Cr, Ni, Pb, Se, C, N, umidade, relacoes C:N, C:CTC (Capacidade de troca de cations) e pH. Os compostos obtidos nas pilhas revolvidas atenderam aos padroes de qualidade, exceto o teor de C, que foi menor. Nos compostos das pilhas com gesso e nao revolvidas, o teor deste elemento excedeu o minimo exigido mas os valores de N, de ovos de helmintos e de umidade, nao corresponderam ao padrao do MAPA. Os teores de metais e de Se dos compostos foram menores que o maximo permitido, exceto o de Cd, cujo teor foi elevado no esterco utilizado nas pilhas sem gesso. Este aditivo decresceu o valor do pH dos compostos e aumentou o teor de N das pilhas nao revolvidas. Em relacao a todos os atributos avaliados, os melhores compostos foram obtidos nas pilhas revolvidas.

Diagnosis and recommendation integrated system (DRIS) of soybean seed oil content

The Diagnosis and Recommendation Integrated System (DRIS) can improve interpretations of leaf analysis to determine the nutrient status. Diagnoses by this method require DRIS norms, which are however not known for oil content of soybean seeds. The aims of this study were to establish and test the DRIS method for oil content of soybean seed (maturity group II cultivars). Soybean leaves (207 samples) in the full flowering stage were analyzed for macro and micro-nutrients, and the DRIS was applied to assess the relationship between nutrient ratios and the seed oil content. Samples from experimental and farm field sites of the southernmost Brazilian state Rio Grande do Sul (28° - 29° southern latitude; 52° -53° western longitude) were assessed in two growing seasons (2007/2008 and 2008/2009). The DRIS norms related to seed oil content differed between the studied years. A unique DRIS norm was established for seed oil content higher than 18.68 % based on data of the 2007/2008 growing season. Higher DRIS indices of B, Ca, Mg and S were associated with a higher oil content, while the opposite was found for K, N and P. The DRIS can be used to evaluate the leaf nutrient status of soybean to improve the seed oil content of the crop.

Utilização de cama sobreposta de suínos e sobressemeadura de leguminosas para aumento da produção e qualidade de pastagem natural

Este trabalho foi conduzido com o objetivo de verificar o efeito da fertilizacao com dois tipos de camas sobrepostas de suinos (CSS), a base de casca de arroz (CA) e maravalha (MA), sobre a producao de uma pastagem natural, com predominio de Axonopus sp. e Paspalum sp., sobressemeada com leguminosas (cornichao e trevo-branco). As camas sobrepostas foram aplicadas em quantidades equivalentes a 180, 360, 540 e 720 kg/ha de P2O5, constituindo quatro niveis de cama de casca de arroz (30, 60, 90 ou 120 t/ha) e quatro niveis de cama de maravalha (20,6; 41,2; 62,2 ou 82,8 t/ha). Foram incluidos dois tratamentos-testemunha: 180 kg/ha de superfosfato triplo (SFT) e ausencia de adubacao (AA). A sobressemeadura das leguminosas foi realizada em maio de 2004 e, a partir de agosto de 2004, foram realizados nove cortes da pastagem, a cada seis semanas. As maiores producoes de materia seca (MS) anuais (setembro/2004 a agosto/2005) com as aplicacoes de cama de casca de arroz foram obtidas nos niveis 30 e 60 t/ha e, com cama de maravalha, nos niveis 62,2 e 82,8 t/ha, que resultaram em producoes de MS de 8.083 e 8.276 kg/ha, superiores as obtidas com superfosfato triplo (4.091 kg MS/ha) e sem adubacao (3.071 MS kg/ha). A producao de MS de trevo-branco aumentou linearmente no outono e no inverno, de acordo com os niveis de adubacao com cama de maravalha, mas nao variaram com a adubacao com cama de casca de arroz. O efeito fertilizante varia entre os tipos de cama sobreposta, que podem influenciar a composicao botânica de pastagens mistas de leguminosas-gramineas.

Morfogênese da grama-tapete em resposta à adubação com dejeto líquido de suínos

Este trabalho teve como objetivo avaliar a morfogenese da grama-tapete (Axonopus affinis) adubada durante dois anos com dejeto liquido de suinos (DLS). Na media de dois anos, foram aplicados 0, 51, 102, 153, 204 e 255m3 de DLS ha-1, calculados para prover 0, 100, 200, 300, 400 e 500kg de N/ha/ano, respetivamente. A morfogenese foi avaliada na primavera e verao de 2008-2009 e 2009-2010, considerando-se como temperatura basal 10°C para calculo da soma termica no intervalo entre as amostragens. Houve aumento linear no numero de perfilhos, taxa de alongamento de perfilhos, taxa de expansao foliar e indice de area foliar em funcao das doses de DLS. Nao houve efeito da adubacao na taxa de alongamento de pseudocolmo (0,004cm GD-1), taxa de aparecimento foliar (0,004 folha perfilho-1 GD-1) e filocrono (274GD).

Leaf tissues proportion and chemical composition of Axonopus jesuiticus x A. scoparius as a function of pig slurry application

This study aimed to evaluate the chemical and anatomical attributes of leaves of giant missionary grass to application of 0, 62, 124, 186, 248 and 310m³ ha-1 of pig slurry. At 83 days after the last application of fertilizer, the leaf blades were collected, fixed in FAA 70%, sectioned, stained, photographed and digitalized. The transversal section of leaf blades were evaluated for proportion of epidermis, lignified vascular tissue + sclerenchyma, non-lignified vascular tissue and parenchyma with an image-processing system calibrated to 1mm pixel-1. Leaf samples were analyzed for crude protein, acid detergent fiber, neutral detergent fiber and hemicellulose content by near infrared reflectance spectroscopy. The pig slurry application up to 310m³ ha-1 significantly increased the percentage of crude protein, parenchyma, epidermis, non-lignified vascular tissue and hemicellulose, while decreasing the percentage of acid detergent fiber and lignified vascular tissue + sclerenchyma. The Pearsons correlation was positive between crude protein and non-lignified vascular tissue, and between acid detergent fiber and lignified vascular tissue + sclerenchyma. The percentage of hemicellulose was positively correlated with epidermis, parenchyma and non-lignified vascular tissue. A negative correlation between acid detergent fiber and epidermis, parenchyma and non-lignified vascular tissue was observed.