Resumo

LOPES THOMAZ, Edivaldo. Temperature effect on aggregate diameter and stability in a Chernozem from Saskatchewan, Canada. Cienc. suelo [online]. 2011, vol.29, n.2, pp.277-284. ISSN 1850-2067.

The role of fire on environmental processes is widely reported in several Earth ecosystems. Fire affects environmental processes (e.g. infiltration, erodibility, organic matter dynamic etc.). The objectives of this laboratory study were: 1) to establish the effect of temperature on aggregate stability in a Chernozem soil from a temperate environment; 2) to evaluate two procedures to detect such effects on soil aggregates (i.e. dry and wet sieving); 3) to use different indexes to measure possible changes in aggregate distribution and stability (mean weight diameter, geometric mean diameter and aggregate stability). The samples were heated in a muffle furnace, and subjected to the following treatments: control (room temperature), 200 oC and 300 oC for 20 minutes and 580 oC for 10 minutes. The Chernozem soil was affected by the different temperatures. At 200 ºC, there was a decrease in the geometric mean diameter, mean weight diameter and the soil aggregate stability. Aggregates of 2.8 mm were most influenced by this temperature. On the other hand, the 580 °C temperature caused an increase in these indexes. The 300 °C temperature caused intermediate response compared to other temperatures. The wet sieving was the most efficient technique to detect the temperature effects on soil.

Palavras-chave : Dry and wet sieving; Mean diameter; Geometric mean diameter.

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