Abstract

FRENE, Juan Pablo; GABBARINI, Luciano Andrés  and  WALL, Luis Gabriel. Effects of tillage systems on microbial structure and activity at microaggregate level. Cienc. suelo [online]. 2018, vol.36, n.2, pp.50-61. ISSN 1850-2067.

The knowledge of the distribution of microorganisms and the enzymatic activitiy at the level of soil fractions aggregates would contribute to a better understanding of the ecosystemic services of the soil. The objective of this work was to determine if two of the most relevant microbial groups, fungi and bacteria, and the biological activity of the soil measured as a respiratory profile induced by substrates and / or the activity of extracellular enzymes, were modified by differential tillage systems, and if that modification was reproduced at the microaggregate level of the soil. Two agricultural farming practices were compared: no-tillage and conventional tillage. The studies were replicated in soils of two different environmentally sites of the Pampean region. The samples were wet sieved, obtaining the following fractions of aggregates: 2000-63, 63-20, 20-2 and 2-0.1 μm. The abundance of bacteria and fungi was estimated by qPCR, finding different abundances according to the size of the aggregates. The physiological profiles at the community level were differentiated according to the aggregates size independently of the tillage management and the sampled site. On the contrary, at the level of aggregates, the enzymatic profiles were differentiated more by soil tillage than by the size of the fraction. These results allow us to suggest that soil ecosystemic services are the result of an integration of the physical structure at the level of aggregates and their own biochemical activities.

Keywords : enzymes; clpp; agriculture managements; soil aggregates fractions.

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