Marciel Redin

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 do cobre na população de bactérias e fungos do solo, na associação micorrízica e no cultivo de mudas de Eucalyptus grandis W. Hill ex Maiden, Pinus elliottii Engelm e Peltophorum dubium (Sprengel) Taubert

Copper is a heavy metal that can have toxic effects on microorganisms and plants. Ectomycorrhizal fungi are able to protect the plant from heavy metal toxicity, but the presence of certain metal concentrations can inhibit the growth of this fungus, damage the mycorrhizal symbiosis and also altering the development of the plants. The aim of this study was to evaluate the effect of copper on soil bacteria and fungus population, as well as the effects on the ectomycorrhizal association in the development of Eucalyptus grandis , Pinus elliottii and Peltophorum dubium seedlings. The survey of the soil microorganism population was carried out in a greenhouse during 60 days and the treatments consisted of applications of copper sulphate (0.7; 0.708; 0.716; 0.724 mg Kg -1 ) to the soil and to eucalyptus and pinus seedlings. Eucalyptus and Peltophorum dubium seedlings inoculated and not inoculated with Pisolithus microcarpus (Cooke and Massee) Cunn (UFSC Pt 116) received copper levels of 0, 100, 200 and 300 mg kg -1 . The height, stem diameter, shoot and root fresh biomass, shoot and root dry biomass and ectomycorrhizal colonization were evaluated at 110 days. Soil bacteria and fungus population were altered by the presence of copper and the eucalyptus and pinus seedlings were not affected by copper addition. The inoculation of the eucalyptus and canafistula seedlings with isolate UFSC Pt 116 favored the height of the plants and the development of shoot and root fresh biomass. According to the results, canafistula was able to form an ectomycorrhizal association with the isolate tested. The eucalyptus and canafistula seedling development was inhibited by copper following inoculation with the UFSC Pt 116 isolate.

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 .

ANÁLISE EVOLUTIVA SÓCIO PRODUTIVA DE ALIMENTOS NA AGRICULTURA FAMILIAR NO MUNICÍPIO DE CRISSIUMAL-RS

A agricultura familiar e considerada a base da producao de diversos alimentos. Porem, nos sistemas de producao atuais, muitas alteracoes socio produtivas estao ocorrendo, levando a reducao de areas de plantio para subsistencia familiar e a perdas de diversidade de culturas. Desta forma, objetivo do presente trabalho foi avaliar as mudancas ocorridas na populacao e producao de alimentos na agricultura familiar do municipio de Crissiumal ao longo dos ultimos anos. A metodologia utilizada para a realizacao do trabalho consistiu em pesquisa de campo com moradores dos distritos do Municipio, bem como com entidades publicas que trabalham diretamente com o setor agricola. Como resultados, observou-se uma reducao drastica na populacao do meio rural, bem como na area destinada a producao de alimentos de subsistencia, de aproximadamente 1,5 a 10 hectares para areas inferiores a 0,5 hectare. Alem disso, observou-se uma reducao consideravel no numero de especies cultivadas, pois antigamente os principais cultivos para o consumo familiar eram: feijao, batata-doce, batatinha inglesa, cebola, amendoim, dentre outros; atualmente, sao produzidos apenas alimentos de consumo primario, como hortalicas, mandioca e batata-doce e, como consequencia disso, pode-se constatar alteracoes nos habitos alimentares, devido a dependencia de alimentos processados. Portanto, contata-se reducao consideravel a partir da revolucao verde? na populacao do meio rural, area e na diversidade de producao de alimentos pelos agricultores do municipio de Crissiumal.

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.