Potential PM10 emission from soil affected by different temperatures in a Caldén Forest of semiarid Pampas, Argentina

Abstract

Wind erosion is a major soil degradation process in arid and semi-arid environments, like the semi-arid region of Argentina. Xerophytic Caldén forests in these areas, often experience natural summer fires which reduce vegetation cover and its protective effect on the soil. PM10 (particles with diameters < 10 µm) emission is part of the wind erosion process. In the Caldén forest, cyclically fires affect the physico-chemical properties of the soil, depending on surface temperatures. However, information on how these changes affect soil susceptibility to wind erosion and PM10 emission is limited. This study aimed to evaluate the effect of temperatures from 100 to 600 °C on Caldén forest soil with varying vegetation cover and its potential to emit PM10 (PE-PM10). Soil samples were collected from Grassland site (gramineous-herbaceous stratum without woody plants influence) and Forest site (shrubby and arboreal stratum). The study evaluated physical (texture, microaggregation, erodible fraction < 0.84 mm) and chemical (total organic carbon −TOC-) surface changes and PE-PM10 after exposure to different temperatures. In both sites, temperatures above 400 °C decreased TOC and altered physical properties by reducing clay and coarse sands content while increasing silt and fine sands content. Erodible fraction increased and the microaggregation decreased with rising temperature. PE-PM10 was correlated in a linear and positive way with temperature in both sites (p < 0.05), with highest emission at 600 °C. Grassland site showed higher emissions than Forest. These results suggested that higher temperatures reduced clay and TOC content, key to soil stability, leading to increased PM10 emissions as microaggregates break down.