Brushfire Affects Soil Microbial Abundance and Enzymatic Activities For Years
- Soil microbes are important in maintaining soil processes such as litter decomposition, nutrient cycling, and plant growth.[1]
- However, there is a lack of understanding about the effect of fire and post-fire management methods on the population and activities of soil microbes.
- A group of researchers from the California State University-San Marcos examined surface soil from unburned, burned and naturally regenerating, and burned but hydroseeded chaparral areas.
- Hydroseeding is the process of spraying a watery mixture of seeds, mulch, and fertilizer.[2]
- The sampling site is within the campus of California State University-San Marcos and had an incident of fire five years ago.
- Researchers analyzed microbial biomass carbon, phylum-level bacterial taxonomic composition, and microbial activities.
- They tried to test if fire and hydroseeding affect the population and activities of soil microbes.
- Researchers discovered that in burned areas, total soil nitrogen and carbon, microbial carbon, enzymatic activity, and nitrification rate are significantly lower compared to unburned areas.
- However, some of these observations were affected by hydroseeding.
- Changes in the composition of colonizing plants and carbon inputs from hydroseeding affected the soil carbon, soil nitrogen, and microbial carbon such that they were all similar in the burned hydroseeded areas and unburned areas.
- Furthermore, no significant differences in taxonomic diversity between the three areas.
- Key carbon cycling enzymes such as β-glucosidase and peroxidase, and nutrient cycling enzymes such as N-acetylglucosaminidase were significantly lower in burned areas.
- The activities of these key enzymes were not affected by hydroseeding and the declines were probably due to the declines in microbial abundance, soil carbon and nitrogen pools, and elevated pH.
- The results suggest that fire and post-fire treatments can affect the abundance and activities of soil microbes for years.
Sources:
Vourlitis, George & Steinecke, Dylan & Martinez, Tanairi & Konda, Karen & Rendon, Roxana & Hall, Victoria & Khor, Sherryca & Sethuraman, Arun. (2022). Fire and post-fire management alter soil microbial abundance and activity: A case study in semi-arid shrubland soils. Applied Soil Ecology. 171. 104319. 10.1016/j.apsoil.2021.104319. https://doi.org/10.1016/j.apsoil.2021.104319
