Impact of fire and post-fire management techniques on soil chemical properties

Abstract

The effects of fire (Control burned soil) and two emergency stabilisation techniques (grass Seeding and straw Mulching) on 20 chemical characteristics were evaluated on 0-5 cm top-soils sampled 1, 90, 180 and 365 days after an experimental fire in a steep shrubland of a temperate-humid region (NW Spain). Most part of pH (in H 2 0 and KC1) variance was explained by the sampling date. No clear temporal trends were identifiable for total soil C and N content, likely due to the large SOM pool in these soils; however, changes on soil 8 13 C were explained by the deposition of 13 C-depleted ashes, followed by its progressive erosion, while those on soil S 15 N were a consequence of fire induced N outputs. After the fire, NH^-N, P, Na, K, Mg, Ca, Mn, Cu, Zn and B concentrations increased, while those of NO^ -N, Al, Fe and Co did not vary significantly. Despite a significant decline with time, concentrations of Mg, Ca and Mn at the end of the study were still higher than in unburned soil, while those of K, Cu, Zn and B were similar to the pre-fire levels and those of Nftf-N, P and Na were below pre-fire values. Mulching and Seeding treatments for burned soil emergency stabilisation had significant effects on soil 8 15 N and extractable K, Mg and Ca, while data were inconclusive for their possible effects on the extractable Al, Fe and Co.

Post-fire nutrient availability in the sub-tropical forest ecosystem of the Koubru Hills, Manipur

“…As confirmed by the two way ANOVA test, fire had no significant effect on the available Mn contents of the 0-5 and 10-15 cm soil layers, although Gomez-Rey et al 29 reported higher post-fire Mn availability in the 0-5 cm soil layer, attributed to Mn supplied by ashes from the burned vegetation. In contrast to the lack of difference in terms of the Mn availability between the burned and unburned areas in the 0-5 and 10-15 cm soil layers, the 5-10 cm soil layer showed a significant post-fire decrease in the available Mn compared with the unburned areas.…”

“…Some recent studies have also reported a decline in the Fe availability of burned soils 18,29,[66][67][68] . The fire induced depletion of the available Fe in the burned area could be associated with losses (by convection in smoke columns, transport by wind, erosion and leaching) and/or conversion to insoluble oxidized forms in soils as have been reported for several other nutrients 25,69 .…”

“…Most studies 17,[27][28][29] show an initial increase in inorganic forms of nitrogen such as NH 4 + -N after fire followed by a decline with time. In the present study, however, we found a decrease in NH 4 + -N concentration of the burned area and the decrease persisted until the study ended.…”

“…However, Close et al 68 and Stankov Jovanovic et al 69 have reported enhanced Zn availability in burned soils due to the release of Zn by ashes from burned vegetation. The available Zn depletion in the 0-5 and 5-10 cm soil layers of the burned area may be attributed to leaching and erosional losses as this element could be quickly leached 75 or lost in eroded sediments 29 .…”

Short-term impact of a wildfire on net and gross N transformation rates

“…In agreement with the findings of other authors, results showed that our burned soil had: a) higher soil pH and electrical conductivity, due to the oxides and carbonates of basic ions supplied by ashes and the combustion of organic acids, that lead to increased extractable Na, Ca and P (see, for example, the review by Certini, 2005); b) lower contents of soil C and N, due to volatilization (Certini 2005), and also lower values of soil d 15 N, related with the deposition of 15 N-depleted charred materials from N 2 -fixing legumes and/or ectomycorhized ericaceous (Gómez-Rey et al 2013b); and c) lower levels of Fe and higher of Mn (Certini 2005;García-Marco and González-Prieto 2008;Close et al 2011;Gómez-Rey et al 2013a). Contrastingly, although several authors reported that fire increases the availability of K, Mg, Zn and Cu in soils (Certini 2005;García-Marco and González-Prieto 2008;Close et al 2011;Gómez-Rey et al 2013a), we did not find a significant effect on these nutrients.…”