Effects of different vegetation types on burnt soil properties and microbial communities

Abstract

The intensive wildfires recurring in the Mediterranean area modify soil physico-chemical properties, in turn inducing changes in soil microbial abundance and activity. Soils were sampled from burnt and adjacent unburnt sites within Vesuvius National Park 1 year after a large wildfire occurred in summer 2017. The aims of the present study were to evaluate the effects of fires on soil characteristics and to investigate whether different plant types contribute to mitigating or enhancing these effects. The results showed lower organic matter and water content and a higher C/N ratio in burnt than in unburnt soils. In particular, this trend was the same for all the plant types investigated, with the exception of soils covered by black locust tree and holm oak, which showed a higher C/N ratio in unburnt than in burnt soils. In soils covered by holm oaks, a shift in the bacterial and fungal fractions occurred between burnt and unburnt soils, whereas the amount of ammonia oxidisers was notably higher in burnt than in unburnt soils covered by black locusts; the highest N concentration was also measured in burnt soils covered by black locusts. The burnt soils showed a lower metabolic quotient and a higher rate of organic carbon mineralisation compared with unburnt soils, and this trend was particularly evident in soils under herbaceous plants. The findings suggest that soils covered by herbaceous species are more sensitive to fire effects and less able to restore their functionality compared with soils covered by trees.

C and N Pools In Afforested Pine Forests and Natural Shrublands 

“…At high elevations, the microbial and fungal biomasses of the shrublands soil were signi cantly reduced compared to those at low elevations, despite being more active. The higher microbial respiration in shrublands soil at high elevations than at low elevations can be a response of the microbial community to stress conditions that stimulate the use of C resources (Liu et al 2019;Panico et al 2020). Moreover, in low-elevation shrublands, the chemical composition of the soluble fraction seemed to con rm the higher resistance to oxidation given the high values of saturated compounds such as alkyls.…”

“…According to Memoli et al (2019) and Panico et al (2020), the higher temperature at low elevation than at high elevation that characterize Vesuvius slopes could have strongly in uenced the soil characteristics and process rates and be at least partly responsible for the highest soil OM contents and C pools in lowelevation pine forests and in high-elevation shrublands. The important role of temperature appeared to be con rmed by the clearly signi cant and positive relationship between the C sequestration rate and mean annual temperature found for different European (North and South Europe) coniferous stands by Berg and McClaugherty (2020).…”

Role of Seasonality and Fire in Regulating the Enzymatic Activities in Soils Covered by Different Vegetation in a Mediterranean Area

“…In the Mediterranean environment, where the frequency of wildfires is high, it is useful to understand the impact of fires on soil microbial properties in order to prevent them and to put into practice strategies aiming to recover burnt areas. By now, it is known that fire effects on soils depend on fire intensity and frequency, but also on vegetation type, climate, fuel load, and topographic characteristics [37][38][39]; fire's effects on soil activities have been investigated to a lesser extent and the results of these studies are still controversial.…”

Response of Soil Bacterial Community to Application of Organic and Inorganic Phosphate Based Fertilizers under Vicia faba L. Cultivation at Two Different Phenological Stages

“…The roots were then gently washed with distilled water to remove residual soil particles. Total soil and chicken manure (PP) DNA was extracted using the Fast DNA™SPIN Kit for soil (MP Biomedicals, Santa Ana, California, USA) according to Panico et al [42]. Quality control and DNA yield were checked by 2% agarose gel electrophoresis and by spectrophotometer (Picodrop limited, Hinxton, UK).…”