Molecular Characterization of Burned Organic Matter at Different Soil Depths and Its Relationship with Soil Water Repellency: A Preliminary Result

Soil water repellency (hydrophobicity) prevents water from wetting or infiltrating soils, triggering changes in the ecosystems. This physical property is directly correlated to the erodibility grade of a soil. Wildfire events may develop, enhance, or destroy soil hydrophobicity, modifying the erodibility grade of a soil and increasing the loss of its most reactive layer (organic matter). To assess the main organic family of compounds (biomarkers) surrogates to fire-induced water repellency, a study was carried out on a fire-affected soil under eucalyptus canopy at two depths (0–2 and 2–5 cm) from Portugal. The potential soil water repellency was measured using the water drop penetration time (WDPT) test. The molecular characterization of hydrophobic biomarkers was carried out using analytical pyrolysis (Py-GC/MS) in combination with multivariate statistical analysis (PCA, MLR). The upper burned soil layer (0–2 cm) displayed a significant contribution of fresh biomass (lignin and polysaccharides), while the deepest (2–5 cm) one showed more humified organic matter (lipids). The soil hydrophobicity was directly correlated to non-polar organic compounds, such as lipids and polycyclic aromatic hydrocarbons (PAHs), and inversely to unspecific aromatic compounds. The combination of mass spectrometry techniques and chemometric analysis allowed obtaining a preliminary forecast model of hydrophobicity degree in fire-affected soil samples under eucalyptus canopy. This analytical approach opens the door to developing more sensitive mathematical models using molecular organic compounds to predict the alteration of hydrophobicity and other soil physical properties induced by fires.

Coniochaeta elegans sp. nov., Coniochaeta montana sp. nov. and Coniochaeta nivea sp. nov., three new species of endophytes with distinctive morphology and functional traits

A growing interest in fungi that occur within symptom-less plants and lichens (endophytes) has uncovered previously uncharacterized species in diverse biomes worldwide. In many temperate and boreal forests, endophytic Coniochaeta (Sacc.) Cooke (Coniochaetaceae, Coniochaetales, Sordariomycetes, Ascomycota) are commonly isolated on standard media, but rarely are characterized. We examined 26 isolates of Coniochaeta housed at the Gilbertson Mycological Herbarium. The isolates were collected from healthy photosynthetic tissues of conifers, angiosperms, mosses and lichens in Canada, Sweden and the United States. Their barcode sequences (nuclear ribosomal internal transcribed spacer and 5.8S; ITS rDNA) were ≤97% similar to any documented species available through GenBank. Phylogenetic analyses based on two loci (ITS rDNA and translation elongation factor 1-alpha) indicated that two isolates represented Coniochaeta cymbiformispora, broadening the ecological niche and geographic range of a species known previously from burned soil in Japan. The remaining 24 endophytes represented three previously undescribed species that we characterize here: Coniochaeta elegans sp. nov., Coniochaeta montana sp. nov. and Coniochaeta nivea sp. nov. Each has a wide host range, including lichens, bryophytes and vascular plants. C. elegans sp. nov. and C. nivea sp. nov. have wide geographic ranges. C. montana sp. nov. occurs in the Madrean biome of Arizona (USA), where it is sympatric with the other species described here. All three species display protease, chitinase and cellulase activity in vitro. Overall, this study provides insight into the ecological and evolutionary diversity of Coniochaeta and suggests that these strains may be amenable for studies of traits relevant to a horizontally transmitted, symbiotic lifestyle.

Bioakumulasi kobalt dan nikel pada tanaman kalakai (Stenochlaena palustris (burm. F.) Bedd) di tanah gambut bekas terbakar desa Pakning Asal, Bengkalis

The last 5 years, palm oil plantation in Pakning Asal, Bengkalis were burned in different frequencies. There were unburned soil and burned soil in several times (2-3 times). Land fires affect the physical chemistry of the soil including macro and micro nutrients in soil as well as surrounding plant growth. One of them is kalakai usually made by vegetables in community. The purpose of this study were to analyze the composition of Co and Ni on roots, stems and leaves of kalakai on peat soil unburned soil and burned soil in several times and determine the content of Co and Ni metal in suitable and safe plants for consumption by the community based on the Acceptable Daily Intake (ADI). Co and Ni analysis was carried out using the Atomic Absorption Spectrophotometer (AAS).The results of the analysis Co content in plants increases on peat unburned soil and Ni content increases on burned peat soil. Based on Acceptable Daily Intake (ADI) on kalakai that grow on unburned peat soil and burned several times 81,76 µg/kg BB/hari dan 57,97 µg/kg BB/hari for Co and 112,56 µg/kg BB/hari dan 119,763 µg/kg BB/hari for Ni. Based on ANOVA test performed with p 0.05 can be concluded that there is a significant difference in roots, stems and leaves growing on peat soil unburned and burned several times.

Impact of post-wildfire stabilization treatments on major and minor topsoil elements in a Mediterranean environment (Croatia): first-year study

<p>In the Mediterranean part of Croatia, wildfires have increased in recent decades raising concerns about soil degradation. Post-wildfire stabilization treatments are used in fire affected areas due to their easy application and possible beneficial effects on soil quality. On 28 July 2019, a moderate to high severity wildfire affected about 900 ha in the central part of Mediterranean, Croatia (43°45'N 15°56'E; 105 m a.s.l.). Wildfire mostly affected abandoned grassing with a dominant culture Aleppo pine (<em>Pinus halepensis</em>), and olive groves (<em>Olea europaea</em>). The effects of wildfire (control (C); uncovered burned soil), and two post-wildfire stabilization treatments (mulches); pine needles (PM) and olive leaves (OM) were evaluated on soil samples (0–5 cm depth) taken during 5 sampling campaigns; 25 days after fire (DAF), 3 months after fire (MAF), 6 MAF, 9 MAF, and 12 MAF. One treatment covered 10 m<sup>2</sup>, and mulches were applied in 0.5 kg m<sup>-2</sup>. The non-destructive analytic method, X-ray fluorescence (pXRF), was used to determine the behavior of total concentrations of nutrients and pollutants in all soil samples. The results showed that Al and P were significantly lowest at PM 12 MAF compared to other dates. The P was also significantly lowest at C 3 MAF than other dates. The Ti was significantly lowest at PM 12 MAF then C treatment, while the Zn was significantly different between PM and OM treatments 12 MAF, with highest values at PM. The Si didn’t vary significantly under mulch treatments, but in C was significantly highest 12 MAF in regard to 25 DAF. The K was significantly highest at both mulch treatments 3 MAF, regard to other dates and C treatment. The Pb showed significant changes only in PM between 3 and 12 MAF, with highest concentrations 12 MAF. The S showed significant difference in C between 25 DAF and 12 MAF with the highest 25 DAF. The effects of fire and mulches during the first post-fire year didn’t show significant change of Ca, V, Cr, Mn, Fe, Co, Ni, Cu, As, Rb, Sr, Y, Zr, Nb, and Th concentrations. These results show that PM had a more notable impact on the concentrations of major and minor topsoil elements in comparison to OM. However, it is concluded that more time is required to complete mulch decomposition and possible increment in soil quality.</p><p><strong>Acknowledgments:</strong> The work was supported by Croatian science foundation under the project “Influence of Summer Fire on Soil and Water Quality” (IP-2018-01-1645).</p>

Influence of experimental fires on mesofauna communities (Collembola and Acari) of two types of meadows

The impact of prescribed fires in grasslands on soil mesofauna was studied in the field experiment. The study was carried out on two types of meadows: on mineral (meadow I) and organic soils (meadow II), near Warsaw (52o10’N; 20o50’E). In November 2007 sampling plots, 1 m2 in size were chosen at random and burned. Soil samples were taken just after fire and in April, July and November, 2008 to the depth of 10 cm from unburned plots (control), at the edge of fire and in burned plots. The soil mesofauna was extracted from soil samples in the Tullgren apparatus. There were not found any effects of prescribed fires on mesofauna densities. However, a slight increase of mesofauna abundance was observed on burned areas 12 months after experimental fires on the meadow I and decrease on the meadow II. Just after fire, on burned areas, only euedaphic species of Collembola were present among mites communities dominated Oribatida, with thick cuticule.

Changes in Multi-Level Biodiversity and Soil Features in a Burned Beech Forest in the Southern Italian Coastal Mountain

In the context of global warming and increasing wildfire occurrence, this study aims to examine, for the first time, the changes in multi-level biodiversity and key soil features related to soil functioning in a burned Mediterranean beech forest. Two years after the 2017 wildfire, changes between burned and unburned plots of beech forest were analyzed for plant communities (vascular plant and cover, bryophytes diversity, structural, chorological, and ecological variables) and soil features (main chemical properties, microbial biomass and activity, bacterial community composition, and diversity), through a synchronic study. Fire-induced changes in the micro-environmental conditions triggered a secondary succession process with colonization by many native pioneer plant species. Indeed, higher frequency (e.g., Scrophularia vernalis L., Rubus hirtus Waldst. and Kit. group, and Funaria hygrometrica Hedw.) or coverage (e.g., Verbascum thapsus L. subsp. thapsus and Digitalis micrantha Roth ex Schweigg.) of the species was observed in the burned plots, whereas the typical forest species showed a reduction in frequency, but not in cover, except for Fagus sylvatica subsp. sylvatica. Overall, an increase in plant species and family richness was found in the burned plots, mainly in the herbaceous and bryophyte layers, compared to the unburned plots. Burned plots showed an increase in therophytes, chamaephytes, cosmopolites, steno-Mediterranean and Atlantic species, and a decrease in geophytes and Eurasiatic plants. Significant differences were found in burned vs. control soils for 10 phyla, 40 classes, 79 orders, 145 families, 342 genera, and 499 species of bacteria, with about 50% of each taxon over-represented and 50% under-represented in burned than in control. Changes in bacterial richness within several families (reduction in Acidobacteriaceae, Solibacteraceae, Rhodospirillaceae, and Sinobacteraceae; increase in Micrococcaceae, Comamonadaceae, Oxalobacteraceae, Pseudomonadaceae, Hymenobacteraceae, Sphingomonadaceae, Cytophagaceae, Nocardioidaceae, Opitutaceae, Solirubrobacteraceae, and Bacillaceae) in burned soil were related to fire-induced chemical changes of soil (pH, electrical conductivity, and cation exchange capacity). No evident effect of the wildfire was found on organic C content, microbial biomass (total microbial carbon and fungal mycelium) and activity, and microbial indexes (fungal percentage of microbial C, metabolic quotient, and quotient of mineralization), suggesting that soil functions remained unchanged in the burned area. Therefore, we hypothesize that, without an additional disturbance event, a re-establishment of beech forest can be expected but with an unpredictable time of post-fire succession.

Effects of Microbial Biomineralization Surface Erosion Control Treatments on Vegetation and Revegetation along Highways

Microbial induced calcite precipitation (MICP) has been widely studied in laboratories to test changes to soil strength and density. Rarely studied is the biogeotechnology’s influence on real-world conditions. Consideration for the natural environment coexisting with treated soil is important, particularly vegetative responses to biochemical and physical changes from treatments. In this factorial designed study, vegetative response from one-time biochemical surficial treatments is observed in four soil growth mediums: two variants burned soil, unburned side slope construction soil, and Ottawa sand. Treatment objectives are to create a light crust that provides short-term erosion control, protects concurrently applied seeds and provides a beneficial plant environment (BPE). The crust creates a BPE through increased soil water retention and shear soil strength allowing better root and plant stability. An overly dense crust prevents root penetration and is avoided because established root systems are crucial in long-term erosion control. This study successfully created such a crust in all soil types treated. Also studied were influences of solution components on germination rates. Component influence proved highly dependent on soil type as calcium chloride inclusion was highly detrimental to seedling success in clean sand, somewhat detrimental to burned soil with ash layer, insignificant in unburned soil, and beneficial to burned soil without ash layer. These results give an indication of the complex biochemical soil reactions occurring from MICP treatment. This study gives evidence that a one-time application of a seeded biochemical solution has real-world potential as a balanced short-term and long-term erosion control technology for burned and construction soils.

Ketersediaan Unsur Besi, Molibdenum, Aluminium dan C/N Total Pada Lahan Gambut Bekas Terbakar Berulang di Kabupaten Bengkalis

Land fire will be impact to the physical and chemical characteristics of soil that caused of decomposition proces. The different land fire frequency will be affect to different in the soil composition. To know how far that the composition is different so it need to do research about the contains of micro element such as Fe, Mo, Al available and ratio C/N in area Pakning Asal, Bengkalis Regency. The contains of Fe and C-organic was determined using Spectrophotometer UV-VIS, the contains of Mo and Al was determined using Atomic Absorbtion Spectrophotometer and the contain of N was determined by Kjeldahl method. Analysis result showed that contains of Fe, Mo, Al and ratio C/N in unburnt soil, once burned soil and several times burned (2 – 3 times in last 5 years) there were 14.1566 mg/Kg; 15.3151 mg/Kg and 5.7677 for Fe; 0,0548 mg/Kg, 0.1345 mg/Kg and 0.0830 mg/Kg for Mo; 12.5655 mg/Kg, 12.2220 mg/Kg and 8.9683 mg/Kg for Al and was increased 16.6855; 20.6787 and 25.5206 for ratio C/N.