Abstract

GABIOUD, Emmanuel Adrián; WILSON, Marcelo Germán  and  SASAL, María Carolina. Application of the le bissonnais method to assess aggregate stability in three soils orders. Cienc. suelo [online]. 2011, vol.29, n.2, pp.129-139. ISSN 1850-2067.

Since aggregate stability is a dynamic characteristic, it is considered a sensitive indicator of a soil undergoing a process of recovery or degradation. In Argentina, different laboratory methods have been used to analyze the aggregate stability variation with respect to soil use. Le Bissonnais method, which is based on the classic Henin method, was developed by the INRA of France. This method provides the mean weighted diameter (DMP) of stable aggregates with three pretreatments: fast wetting (DMPE), mechanical disintegration followed by re-wetting with ethanol (DMPD), and slow wetting (DMPC). The average value is then used to determine a value that summarizes the information (DMPm). At a global level, this method has been used on different soils under varying climatic conditions. However, since its performance on Argentinian soils is not yet known, the aims of this work were: i) to evaluate the method of Le Bissonnais as an indicator of degradation in three types of soil (Mollisol, Vertisol and Alfisol) with different degrees of intervention; ii) to relate the DMP with organic carbon content; iii) to correlate the methodologies of Le Bissonnais and Hénin and iv) to quantify the time consumed by the aggregate stability procedure. Le Bissonnais method discriminated different use and management conditions in the three soils, reflecting trends towards either deterioration or recovery. We found a significant and positive relationship between carbon content and aggregate stability (R²=0.30), and a significant correlation between both methods (r=0.51). The latter varied according to the soil, existing a high degree of correlation in the Mollisols, an intermediate degree of correlation in the Alfisol and no correlation in the Vertisol. There were associations between the coefficients of variation of both methods, being higher in those determined by Hénin. The results will contribute to gain insights into the analysis of the mechanisms of aggregation and disaggregation of each soil in relation to production systems. In turn, the determination of the threshold values of the resource will reveal trends and generate early warning of degradation processes.

Keywords : Aggregate stability; Le Bissonnais method; Mollisol; Vertisol; Alfisol.

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