Water repellency and moisture content spatial variations under Rosmarinus officinalis and Quercus coccifera in a Mediterranean burned soil

作者：Gimeno Garcia Eugenia^*; Antonio Pascual Juan; Llovet Joan

来源：Catena, 2011, 85(1): 48-57.

DOI：10.1016/j.catena.2010.12.001

• Soil hydrophobicity
• Soil moisture content
• Wildfire
• Mediterranean shrubland

Variations in the distribution pattern of soil water repellency (SWR) and soil moisture are of major importance for the hydrological and geomorphological processes in Mediterranean burned areas, and also for their ecological implications concerning to re-establishment of the vegetation cover. This paper studies the influence of Rosmarinus officinalis L and Quercus coccifera L vegetated patches on SWR and their relationships with soil moisture content (SMC) and soil organic matter (SOM) in burned and unburned calcareous soils of a Mediterranean shrubland ecosystem, considering the first rainfall event occurred after the wildfire in Les Useres (Castellon, eastern Spain).
In a burnt SSE facing hillslope (739605 West, 4449022 North), 8 microsites were selected under Q. coccifera and 20 under R. officinalis. Three concentric zones were distinguished around the plants: Zone I (stump), Zone II (intermediate) and Zone III (bare soil), showing differences on its soil surface appearance, which were considered for soil sampling and for field moisture measurements. In the nearest unburned zone, at the same hillslope, 8 microsites for each of the same species were also selected, on the basis that they were representative of the pre-fire conditions.
The obtained results imply that fire caused a significant increase in SWR at R. officinalis stumps (measured by means of the water drop penetration time test, WDFT). However, at burned Q, coccifera microsites. SWR was destroyed by fire, at least in the 2 mm soil fraction (WDPT<5 s). Results also showed the presence of a gradient from the highest WDPT and SOM at Zone I to the lowest at Zone III for the two studied species, in that way that bare soil was wettable at burned and unburned microsites and this fact is also reflected on the spatial distribution of SMC. Field SMC showed an increasing gradient from the stumps towards the outer zone, and the differences between SMC in the stumps and bare soil were greater from burned than unburned microsites. Field SMC showed significant and negative correlation coefficients with the WDPT and SOM content for the two studied species. Moreover, a positive relationship between WDPT and SOM was found. Partial correlation analysis at burned microsites revealed that SMC and WDFT are influenced by the SOM. The hydrological and ecological implications of these results are discussed.

• 出版日期2011-4