Effects of fire on cation content in water: a laboratory simulation study

Abstract

Laboratory experiments were carried out to explore the effect of thermal shocks (as occur during fire) and simulated rainfall events on cation leaching dynamics in an organic rich Leptic Umbrisol soil. The soil samples were collected in the field using specially designed lysimeter boxes that allow sampling and application of thermal shock treatments and simulated rainfall while keeping the soil structure unaltered. The soil temperature during the thermal shocks and degree-hours of accumulated heat were determined, and cation (Na+, K+, Ca2+ and Mg2+) leaching was measured in surface runoff (0-cm depth) and subsurface flow (12-cm depth) samples collected from the lysimeter boxes. Important differences were found in cation leaching in relation to thermal shock: monovalent cation leaching from the soil above 200°C (68 degree-hours) and divalent cations leaching above 220°C (195 degree-hours) was higher than that seen in other treatments. In general, the amount of cations leached increased with the severity of the thermal shock; however, under moderate conditions, there was a decrease in cation leaching, mainly of monovalent ions. The exchangeable cation losses by leaching in the intense heat treatments were ~80%.

Drought and its legacy modulate the post‐fire recovery of soil functionality and microbial community structure in a Mediterranean shrubland

“…The lower concentration of exchangeable potassium in burned soils under natural rainfall conditions compared to unburned ones does not coincide with previous studies (Caon, Vallejo, Ritsema, & Geissen, ; Certini, ), which reported an ephemeral increase in potassium after fire. Such contrasting results may be due to the fact that, as our first soil sampling was carried out 8 months after fire, leaching or surface runoff may have occurred in the period between fire and sampling (Cancelo‐González, Rial‐Rivas, & Díaz‐Fierros, ).…”

Short-time phosphorus losses by overland flow in burnt pine and eucalypt plantations in north-central Portugal: A study at micro-plot scale

“…Post-fire losses of P by overland flow, however, have been poorly investigated (Cancelo-González et al, 2013;DeBano et al, 1998;Díaz-Fierros et al, 1990;Lasanta and Cerdà, 2005). In Portugal, particularly few studies have measured post-fire P export by overland flow (Coelho et al, 2004;Ferreira et al, 1997Ferreira et al, , 2005Thomas et al, 1999Thomas et al, , 2000aThomas et al, , 2000bWalsh et al, 1992), especially considering the more than 100.000 ha that are burnt each year.…”

Glomalin‐related Soil Protein Response to Heating Temperature: A Laboratory Approach

“…SOC curves followed a very similar trend, and relevant effects at low temperatures were not observed. Neither qualitative nor quantitative changes in SOC have been observed at low temperature ranges between 150°C and 220°C (Fernández et al, 1997;Badía & Martí, 2003). Main changes occur at intermediate temperatures (Certini, 2005).…”

“…Thus, this older, more recalcitrant GRSP would become measurable (at highest temperatures) with the breakdown of aggregates when the organic matter combustion takes place, which could be the explanation for the increases observed in most cases in the temperature range between 180°C and 200°C (Figure 2). Many authors (Badía & Martí, 2003;García-Corona et al, 2004;Marcos et al, 2007) have described a decrease in AS with temperature in laboratory heating. Zavala et al (2010) did not find a decrease in AS at temperatures below 150°C but did at 250°C in sandy loam and loamy sandy soils.…”