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Accueil du site → Doctorat → Argentine → Comunidades bacterianas en suelos bajo siembra directa en la región agropecuaria pampeana. Influencia del manejo y propuesta de nuevos indicadores biológicos

Universidad de Buenos Aires (2012)

Comunidades bacterianas en suelos bajo siembra directa en la región agropecuaria pampeana. Influencia del manejo y propuesta de nuevos indicadores biológicos

Guerrero, Leandro Demián

Titre : Comunidades bacterianas en suelos bajo siembra directa en la región agropecuaria pampeana. Influencia del manejo y propuesta de nuevos indicadores biológicos

Bacterial communities in soils under no-till crop production in the pampas region. Influence of management and proposal of new biological indicators

Auteur : Guerrero, Leandro Demián

Université de soutenance : Universidad de Buenos Aires

Grade : Doctor de la Universidad de Buenos Aires en el área de Química Biológica 2012

Résumé
The soil is considered one of the most diverse and heterogeneous environments. They produce many processes that enable the recycling and transformation of substances essential for plant life and animals. Most of these processes are performed by bacteria, and are affected by different factors in the environment. One of the main causes that modify these ecosystems is agricultural production. The recent development of new technologies, such as no-till crop could reduce the impact of this exploitation. However, the sustainable use also involves the implementation of management practices, including crop rotations, nutrient replenishment and integrated pest management. In this work we have studied the composition and dynamics of bacterial communities under contrasting no-till crop systems in order to determine how impacts on soil, and to find variations in the communities that can serve as biological indicators of soil quality. For the study, two tillage treatments that differ mainly in the rotation regime and other features that separate into good and poor agricultural practices were analyzed. Data were collected from four different locations in the region from the province of Cordoba to Entre Rios for a period of two years. Using molecular tools we found that the differences between the different environments at the level of bacterial communities and major taxa, are influenced primarily by geographic differences and in lesser extent by the effects of land use. As we increased the level of taxonomic resolution, we found that there were differences for certain groups that can separate good from poor practices. The number of bacteria belonging to the Acidobacteria Gp1 group and the genus Rubellimicrobium varied depending on the treatments, suggesting that they could be potential candidates indicators of soil quality. To this end we propose the confection of an index calculated as the ratio (Acidobacteria Gp1/Rubellimicrobium) between the proportion of each group of bacteria found in the sample and the number found in a nearby grassland soil.

Mots clés : MICROBIOLOGIA DE SUELOS ; DIVERSIDAD BACTERIANA ; SIEMBRA DIRECTA ; INDICADORES BIOLOGICOS ; ARNR 16S ; SOIL MICROBIOLOGY ; BACTERIAL DIVERSITY ; NO-TILL CROP ; BIOLOGICAL INDICATORS ; 16S RRNA

Présentation (Biblioteca Digital)

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Page publiée le 24 février 2016, mise à jour le 3 juillet 2017