Abstract

TOURN, Santiago Néstor; AGOSTIN, María de los Ángeles; DOMINGUEZ, Germán Franco  and  STUDDERT, Guillermo Alberto. Evaluation of methods to determine soil structural stability in a southeastern pampas mollisol. Cienc. suelo [online]. 2020, vol.38, n.2, pp.355-365. ISSN 1850-2067.

Soil health is related to aggregate stability (EA) and, therefore, it is important to monitor its status frequently. The methods to do this should simulate the disruption forces that occur in the soil, ought to be sensitive and fast, and would have to be usable for different soil conditions. There is not agreement about the best methodology for the loam and high-organic-matter soils of the Southeastern Buenos Aires province (SEB). The objective of this work was to evaluate three laboratory methods to determine EA. Four soil use and management situations of a Typic Argiudoll soil were selected: a) park, b) continuous cropping under no-tillage, c) continuous cropping under conventional tillage, and d) degraded soil. Soil samples were taken at 0-5 and 5-20 cm and their EA was determined through: M1: Six et al. (1998); M2: De Leenher & De Boodt (1958) modified by Suero & Garay (1978), y M3: Le Bissonnais (1996). Soil total (COT), particulate (COP), and mineral-associated (COA) organic carbon were also determined. Results are shown for 0-5, 5-20, and 0-20 cm layers. The EA determined through all three methods showed a highly significant correlation with COT and COP for all three depths (r 0.91-0.98). All the methods required approximately the same time to obtain the final result of each sample. Besides, their results highly correlated with the results of each other (r 0.86-0.98). However, methods M1 and M2 allowed distinguishing soil use and management situations more sensitively than M3. Therefore, it is recommended to use either M1 or M2 for specific studies of EA on soils of the SEB with loam surface texture. Nevertheless, it is necessary to evaluate the performance of these methods for a broader range of textural classes and management situation to be able to confirm this.

Keywords : Soil health; mean weight diameter; change of mean weight diameter.

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