Effects of prescribed burning for pasture reclamation on soil chemical properties in subalpine shrublands of the Central Pyrenees (NE-Spain)

Abstract

The abandonment of the traditional pastoral activities in the subalpine grasslands of the Central Pyrenees (NE-Spain) has resulted in shrub encroachment processes that are dominated by species such as the Echinospartum horridum. Therefore, prescribed burning has been recently readopted in this region as a management tool to stop the spread of shrubs and recover grasslands. We aimed to assess the effect that this practice may have on soil chemical properties such as SOC, N, pH, EC, water-extractable and exchangeable cations (Ca, Mg and K), cation exchange capacity, inorganic N forms (N-NH and N-NO) and available P. We studied two prescribed burnings conducted at the subalpine level of the Central Pyrenees in the municipalities of Tella-Sin (April 2015) and Buisán (November 2015). At each site, the topsoil was sampled in triplicate at soil depths of 0-1, 1-2 and 2-3 cm immediately before (U), immediately after (B0) and one year after (B12) burning, and litter and/or ashes were removed prior to sampling. The results indicate that in the B0 samples, burning significantly reduced the SOC and N contents as well as the exchangeable Ca and Mg at 0-1 cm, whereas the rest of the studied properties remained virtually unchanged. However, in the B12 samples we detected a decrease of nutrient content that was probably related to leaching and/or erosion processes.

Long-Term Evolution of Shrub Prescribed Burning Effects on Topsoil Organic Matter and Biological Activity in the Central Pyrenees (Ne-Spain)

“…Otherwise, EC shows a significant correlation with the main exchangeable cations (Ca 2+ and Mg 2+ ) and organic matter. Many authors have also found that pH and EC sometimes are not affected the same way after a fire (Girona-García et al, 2018c;Granged et al, 2011;Mills and Fey, 2004), while others like Muñoz-Rojas et al (2016) have found, in fact, a high correlation between them. The decrease in EC and the main exchangeable cations over time is not surprising in an environment with about 1700 mm/yr of MAP (Úbeda et al, 2005;Ulery et al, 1993) and with a recovering vegetation Table 4 Evolution of properties (0-1, 1-2 and 2-3 cm depth) for unburned and burned soils (at 0, 6 and 10 years after burning): pH, Electrical conductivity (EC) and Exchangeable cations (Ca 2+ , Mg 2+ , K + ).…”

“…that absorbs essential nutrients (Alcañiz et al, 2016). The incorporation of basic ash, rich in soluble ions and salts (Muñoz-Rojas et al, 2016), into the soil is likely to happen and causes these parameters to increase in the short term (Alcañiz et al, 2018;Gil et al, 2010), sometimes right after the PB (Francos et al, 2019;Girona-García et al, 2018c;Granged et al, 2011) and sometimes within the next few years (Alcañiz et al, 2016;Fontúrbel et al, 2016;Girona-García et al, 2018c). Those effects are expected to disappear in the mid-and long-term.…”

Dynamics of topsoil carbon stocks after prescribed burning for pasture restoration in shrublands of the Central Pyrenees (NE-Spain)

“…2) moisture and amount of fuel loads (Neary et al, 1999); 3) weather conditions (Fernandes et al, 2013); 4) soil water content (Massman, 2012); 5) the sampled soil thickness (Badía-Villas, et al, 2014) and 6) whether the ashes were completely removed prior to sampling (Girona-García et al, 2018b).…”

Los Incendios Forestales Afectan Las Propiedades Físicas Del Suelo

“…Los suelos constituyen un recurso indispensable para la vida, siendo primordiales para nuestra sobrevivencia (CRUZ et al, 2004;RAMÍREZ;SÁNCHEZ, 2012). Sin embargo, este recurso ha estado sujeto a fuertes presiones generadas por diversas actividades, entre las que destacan los incendios forestales.…”