Responses in Soil Carbon and Nitrogen Fractionation after Prescribed Burning in the Montseny Biosphere Reserve (NE Iberian Peninsula)

Abstract

Prescribed fire is one of the most widely-used management tools to recover encroached rangelands. Fire has been reported to cause changes in the soil physical and chemical properties. However, the legacy effects of former plant species on soil responses to fire remains unknown. The legacy effect of the former extant plant species on soil carbon (C) and nitrogen (N) fractionation distribution after prescribed burning in topsoil (0–5 cm and 5–10 cm) was investigated in Mediterranean shrublands in Montseny. We sampled soils under five vegetation patch types: Cytisus scoparius L., Calluna vulgaris L., Erica arborea L., Pteridium aquilinum L., and Cladonia biocrusts, pre- and post-burning. Multivariate analysis on soil C and N fractions showed that soils under the legume Cytisus and the biocrust were the most differentiated. Vegetation patch types tended to respond differently to burning, soils under Cytisus, Cladonia and Calluna showing the strongest response. Total C and N, and C and N in sand decreased after burning in the 0–5 cm soil layer. Conversely, C in silt, as well as N in clay and silt, increased with soil depth after burning. This study will be helpful for understanding ecological legacy effects and their possible consequences when planning prescribed burning.

Effects of the Severity of Wildfires on Some Physical-Chemical Soil Properties in a Humid Montane Scrublands Ecosystem in Southern Ecuador

“…For example, Bielefeld et al [85] determined that, in general, at this depth, fire directly affects soil physicochemical properties as they are exposed to surface heating [12]. This has been corroborated by works such as Chowdhury et al [73] who found that a large part of the thermal energy generated during a fire is lost in the atmosphere, and a smaller amount is radiated downward and absorbed by organic matter. In this context, regarding the bulk density of the most recent and high severity fire (1B-HS: 2019, 2 years since the fire) (Table 2), it coincides with the results obtained by Goforth et al [84] and Chandra and Bhardwaj [18] who showed that when fires are of high severity, the bulk density tends to increase in value and generates greater soil compaction.…”

“…Soil samples were taken at each corner of each plot at a depth of 0-10 cm, using standardized metal cores (6 cm diameter, 10 cm height, 283 cm 3 volume) [71]. The 0-10 cm depth was considered because generally, at this depth, fire increases soil temperature and affects the main physical and chemical properties, as reported in previous research [72,73]. In each plot, 4 samples were taken separately for further analysis of bulk density, texture, pH, soil organic matter (SOM), and total soil nutrients (3 years × 2 study sites × 2 treatments × 3 plots × 4 samples = 144 individual samples).…”

“…The total nitrogen (TN) of the soil was determined by the Kjeldahl method. The available phosphorus content was determined by the modified Olsen method [73,77]. Total potassium (cmol/kg), total calcium (cmol/kg), total magnesium (cmol/kg), total manganese (mg/kg), total copper (mg/kg), and total zinc (mg/kg) were determined by the atomic absorption spectrophotometry method [78].…”

Seasonal Effects of Wildfires on the Physical and Chemical Properties of Soil in Andean Grassland Ecosystems in Cusco, Peru: Pending Challenges

“…Soil nitrogen concentration (N) (%) was assessed using the Micro-Kjeldahl method [48], and soil organic matter (OM) (%) was determined using the Walkley and Black method [49]. Potassium (K) (ppm) was estimated using the NH4 method [50], while soil available phosphorus (P) (ppm) was determined using the modified Olsen method [51]. Additionally, electrical conductivity (mmhos/cm) (EC) was evaluated using a conductivity meter.…”

Effects of Low-Severity Fire on Soil Physico-Chemical Properties in an Andean Páramo in Southern Ecuador

“…Soil organic carbon (SOC) and soil organic matter (SOM) were determined by the method of Walkley and Black [65,66], for which the sample was placed in an oven at 125 • C for 45 min, after oxidation in a solution of K 2 Cr 2 O 7 /H 2 SO 4 . Soil ammonia nitrogen concentration (SAN; mg/kg) was measured by the colorimetric method [67], while soil available phosphorus (P; mg/kg), potassium (K; meq/100 g), calcium (Ca; meq/100 g), and magnesium (Mg; meq/100 g) were determined by the modified Olsen method [68].…”