Eduardo Lorensi de Souza

Impactos da queima sobre atributos químicos, físicos e biológicos do solo

The objective of this study was to verify through literature review the possible impacts of the use of fire on the physical, chemical and biological attributes of soil. In relation to physical attributes, the fire may cause a decrease in the volume of macropores, the size of aggregates, the rate of infiltration of water into the soil and consequently its humidity, and an increase in the resistance to penetration of roots and soil density. Moreover, the soil becomes more susceptible to erosive process due to the removal of its vegetation cover. As for the chemical attributes, many studies focusing on chemical properties have reported an increase in levels of N, P, Ca, Mg, among others mineralized after the passage of fire because the ashes have high concentrations of these nutrients. Burning also reduces the input of organic matter and therefore alters the carbon cycle, contributing to the emission of greenhouse gases into the atmosphere. In relation to biological attributes, the action of flame reduces the availability of food (energy supply) for microorganisms, mainly reducing the population of mesofauna soil. In general, from the works reviewed, it appears that both the burning of pastures and natural fields as well as crop residues and forest areas, should be avoided as a routine practice, because in general, it directly or indirectly degrades the soil. However, depending on the situation and the production system, burning may be an indispensable alternative.

Metais pesados, agrotóxicos e combustíveis: efeito na população de colêmbolos no solo

The aim of this research was to evaluate the collembola development in soils with different levels of heavy metals, fuels and pesticides, in laboratory conditions. Treatments were: Cadmium - 1, 10 and 100mg kg-1 soil; Copper - 50, 500 and 5000mg kg-1 soil; Zinc - 100, 1000 and 10000 mg kg-1 soil; fungicide epoxiconazol + piraclostrobina - 1 and 2L ha-1; fungicide epoxiconazol - 0,75 and 1,5L ha-1; herbicide glyphosate - 2 and 4L ha-1; burned lubricating oil - 5, 50 and 100mL kg-1 soil and diesel oil - 5, 50 and 100mL kg-1 soil and control. In the 1mg kg-1 dose of Cd there was a great increase of the collembola population and the soil pH decreased as the Cd, Zn and Cu doses in the soil increased. In the presence on fuels the collembola presented incapacity to procreate regardless the dose applied in the soil. The number of collembola showed an increase with increasing glyphosate and epoxiconazole level. The heavy metal Cu and Zn have negative impact over the collembola population and just Cd (1mg kg-1 soil) offers increase on their population in the soil. The presence of burned oil and diesel in the soil inhibit the collembolan development in the soil. The pesticides glyphosate, epoxiconazol and epoxiconazol + piraclostrobina do not negatively influence the collembola population in the soil.

Efeito da inoculação com isolados de fungos ectomicorrízicos sobre o desenvolvimento de mudas de Eucalyptus grandis Hill ex Maiden

No Estado do Rio Grande do Sul, os reflorestamentos de eucalipto tem se concentrado em solos com baixa fertilidade natural, e o desempenho dessas mudas podera depender da formacao da associacao ectomicorrizica. Nesse trabalho, avaliou-se o efeito da inoculacao dos isolados de fungos ectomicorrizicos UFSC-Pt116, UFSC-Pt188 e UFSC-SA9, individualmente e em mistura, sobre mudas de Eucalyptus grandis . As avaliacoes foram realizadas aos 30, 45, 60, 75 e 90 dias apos semeadura. A inoculacao individual do isolado fungico ectomicorrizico UFSC-Pt116 promoveu maior altura e massa seca da parte aerea. As mudas inoculadas com mistura dos isolados fungicos UFSC-Pt116 + UFSC-Pt188 + UFSC-SA9 acumularam maior quantidade de fosforo aos 90 dias. Para os teores de nitrogenio e potassio, e massa seca de raizes nao mostrou diferenca significativa entre os tratamentos.

Estabelecimento a campo de mudas de Eucalyptus grandis micorrizadas com Pisolithus microcarpus (UFSC Pt 116) em solo arenoso.

The aim of this work was to evaluate the survival and the initial growth of mycorrhizated eucalypts with Pisolithus microcarpus (UFSC Pt 116) ectomycorrhizal fungus, after its transplant to area subject to the arenization process in Sao Francisco de Assis, RS. The area was divided into four blocks, each one with four treatments (fertile turf with and without mycorrhizae, Quartzarenic Neosoil with and without mycorrhizae). Each parcel was composed of 16 seedlings arranged in four lines in the spacing of 1,5 m x 1,5 m, totalizing in each block 64 seedlings. 90 days after the planting in the field, the eucaliptus seedlings produced in turf with fungus in the fertile substratum presented a survival rate of 100 %, whereas for those produced in fertile turf without fingi, the survival rate was 92 %. The seedlings produced in the Quartzarenic Neosoil with and without mycorrhizae had a survival rate varying around 98 and 89 %, respectively. The produced seedlings with turf and fungus showed significant differences in height and stem diameter. This study showed that the Eucalyptus grandis seedlings produced in substratum fertile turf and inoculated with the Pisolithus microcarpus (UFSC Pt 116) isolated may maintain good development and establishment in the field.

FUNGOS ECTOMICORRÍZICOS NA PRODUÇÃO DE MUDAS DE Eucalyptus grandis W. Hill ex. Maiden EM NEOSSOLO QUARTZARÊNICO

In Rio Grande do Sul state, the eucalyptus planted forests are cultivated in low fertility soils, which contribute to ectomycorrhizal association. This study evaluated the effect of ectomycorrhizal isolates UFSC-Pt116, UFSC-Pt188 and UFSC-SA9 inoculation, individually and in combination, with Eucalyptus grandis in Quartzarenic Neosols. Evaluations were performed at 30, 45, 60, 75 and 90 days after sowing. Plants inoculated with isolates UFSC-Pt116, UFSC-Pt188 and UFSC-SA9 showed highest height, stem diameter, dry mass of shoot and root volume than the control. Plants inoculated with the ectomycorrhizal fungus isolate UFSC-Pt188 showed highest content of phosphorus and potassium in shoots than non-inoculated plants. Inoculation individual ectomycorrhizal isolate UFSC-Pt116 promoted the highest height and shoot dry mass. For nitrogen and potassium, and root biomass have not showed significant differences between treatments. Then inoculation with ectomycorrhizal UFSC-Pt116, UFSC-Pt188 and UFSC-SA9 alone promoted highest height, stem diameter, dry mass of shoot and plant root volume of Eucalyptus grandis .

Eucalyptus grandis Hill ex Maiden inoculated with Pisolithus microcarpus (UFSC-Pt116) in land subject to the sandy process in Southern Brazil

Eucalypts is one of the main species used for commercial reforestation in the Rio Grande do Sul State, Brazil. This study aimed to evaluate the survival and early growth of eucalyptus trees in an area subject to sandy process after three years of growth. The Eucalyptus grandis seedlings were grown in a greenhouse, inoculated or not with the isolated ectomycorrhizal Pisolithus microcarpus (UFSC-Pt116), produced in peat or Entisol. After 120 days, the seedlings were transplanted to an area subject to the sandy process, in the São Francisco de Assis city, RS. The plants have been evaluated regarding survival, height, stem diameter, nitrogen, phosphorus and potassium levels and total phosphorus, inorganic phosphorus, organic phosphorus and wood production on different days after planting. The seedlings grown on the Entisol which was inoculated with the isolated UFSC-Pt116 presented higher survival rates, height, stem diameter, nitrogen concentration and wood production then non-inoculated seedlings. Inoculation with ectomycorrhizal fungi enhanced the production of E. grandis seedlings in survival rates, height, stem diameter.

QUALIDADE DO LEITE: VISÃO DE PRODUTORES RURAIS DO MUNICÍPIO DE SÃO MARTINHO - RS

O leite e um alimento que apresenta uma das mais completas fontes de nutrientes, contendo proteinas, lipideos, carboidratos, vitaminas e sais minerais. A atividade leiteira apresenta impacto socioeconomico significativo na Regiao Celeiro do Estado do Rio Grande do Sul, e e um mercado que esta se tornando cada vez mais exigente, em relacao a qualidade do produto. O maior problema verificado no Rio Grande do Sul e mais especificamente na Regiao alvo deste estudo, foram as diversas fraudes realizadas com esta materia-prima de origem animal. Diante desta problematica, o presente trabalho teve o objetivo de identificar e relatar o ponto de vista de produtores rurais em relacao as adulteracoes de leite que vem sendo praticadas, e que foram investigadas e denunciadas na “Operacao Leite Compensado”, pelo Ministerio Publico Estadual. Para isso, utilizou-se um questionario semiestruturado, que foi direcionado para 20 produtores de leite do municipio de Sao Martinho-RS. Os principais resultados demostraram que a maioria dos produtores estavam preocupados com todas as fraudes descobertas, declararam apoio as investigacoes e tambem evidenciaram a preocupacao com a producao e venda de um produto de qualidade, considerando especialmente os aspectos relacionados a higiene durante a ordenha, alimentacao e a sanidade dos animais como principais fatores para a producao de um leite de qualidade. Portanto a adulteracao e um problema muito grave e que pode alterar a qualidade do produto e comprometer a cadeia produtiva.

Desempenho agronômico de milho crioulo em diferentes níveis de adubação no Sul do Brasil

Ao longo dos ultimos 30 anos, as tradicionais variedades crioulas, foram substituidas por cultivares hibridas, com maior potencial produtivo, mas que exigem mais tecnologia para expressar seu potencial produtivo e consequentemente a um aumento consideravel no custo de producao, tornando-se inacessivel a grande parte dos pequenos agricultores. O presente estudo teve como objetivo, avaliar o potencial produtivo de variedades de milho (Zea mays L.) crioulo na Regiao Noroeste do Rio Grande do Sul. O experimento foi instalado no campo, avaliando-se uma cultivar hibrida comercial e duas variedades de milho crioulo, ambos com e sem adubacao mineral. O delineamento experimental foi em blocos ao acaso (DBC) em plantio direto, com quatro repeticoes, totalizando seis tratamentos. As parcelas foram delimitadas com tamanho de 3,2 x 2 m e espacamento de 0,80 m entre linhas com uma densidade de cinco sementes por metro linear. Nesse estudo foram avaliados os seguintes parâmetros: produtividade de graos (PG), peso de mil graos (PMG), peso de espiga (PE) e altura de planta (AP). Os materiais avaliados diferiram quanto a PMG, destacando-se a variedade bico de ouro que obteve maior peso de grao, os demais parâmetros avaliados nao demostraram diferenca significativa. As variedades de milho crioulo apresentaram adaptabilidade suficiente para produzir igual ou superior a variedade de milho hibrida, mostrando-se uma opcao alternativa de renda e producao de alimento para o agricultor familiar.

A adição de xisto retortado aumenta a retenção do carbono de resíduos vegetais no solo

The objective of this work was to evaluate the short-term and the residual effect of retorted oil shale (ROS) rates on the C retention of crop residues in the soil. The mineralization and C retention of soybean leaves and stems enriched with 13C were evaluated, in soil with and without history of ROS application and in the presence and absence of increasing ROS rates. There was a short-term effect of ROS on C retention in the soil. This effect only occurred with the mixture of leaves + 3 Mg ha-1 ROS, in which C retention in the soil surpassed by 21% the one observed with the sole application of leaves. ROS has the potential to retain C in the soil.