Short-Term Effects of Experimental Fire on Physicochemical and Microbial Properties of a Mediterranean Cambisol

Abstract

Little is known about the bonfire impact on microbial properties in soil. This work aimed to study moderate- to high-severity experimental burning (250 °C) compared to unburned Cambisol in a natural Mediterranean environment (Croatia) on selected soil properties. The soil was sampled immediately and 1, 2, 4, and 6 months after the fire. The fire increased the mean weight diameter, water stable aggregates, and water repellence in different soil fractions, and the observed effect was the strongest immediately after the fire. It also altered soil pH, electrical conductivity, total nitrogen carbon, and sulphur content, and completely destroyed carbapenem-resistant bacteria, but did not significantly affect the soil’s mineralogical properties. Six months after the fire, most microbial properties (save for pH) returned to near control values. Heterotrophic, sporogenic, and phosphate-solubilising bacteria started to recover after a month, whereas the population of carbapenem-resistant bacteria was destroyed initially, but recovered by the fourth month after the fire. Dehydrogenase activity was not significantly affected, but proper recovery started four months after the fire. Even though Cambisol showed some resilience to fire and its properties mostly returned to normal by the sixth month, and a full recovery is expected to occur later, as vegetation returns.

Combined Use of a Bacterial Consortium and Early-Colonizing Plants as a Treatment for Soil Recovery after Fire: A Model Based on Los Guájares (Granada, Spain) Wildfire

“…However, our work, although limited to the cultivable portion of the population, found that the predominant genera in these soils were Peribacillus or Bacillus , as is also reflected in the studies by Matos et al [ 92 ]. A recent study by Hrenović et al also showed these trends as well as an increase in phosphate binders in emerging communities [ 93 ]. In our study, we were able to verify that both this group and the potassium fixators were present; however, they had a smaller population and were less effective than the strains isolated from the sampling points not affected by fire.…”

Conceptual Model for Integrated Meso-Scale Fire Risk Assessment in the Coastal Catchments in Croatia

“…Climatic and biophysical characteristics of the Mediterranean (such as high temperatures during summer, the availability of fuel, i.e., dry vegetation) make the region fire-prone: naturally induced open fires have historically been present and helped form and shape the current landscape. However, population migration from rural to urban areas and the abandonment of agricultural lands, coupled with the effects of climate change, have resulted in the increased frequency and magnitude of fires [21]. In 2021, approximately 5000 km 2 of area was burned in the European Union [22].…”

Mid-Term Effects of Fire on Soil Properties of North-East Mediterranean Ecosystems

“…A number of studies have reported that fire can dramatically change the soil's chemical, physical, and biological properties, with subsequent effects on ecosystem dynamics [1][2][3][4].…”