Unaffected Soil Research Articles

Bio-fertilization of arid lands by terrestrial snails-targeting the wider physiological, geomorphological and agricultural perspectives

Surveys in arid regions worldwide reveal the widespread presence of naturally found Terrestrial Snails (TSs) in extreme arid and semi-arid regions and poor soil conditions such as eroded loess plains. A significant beneficial connection between TS and their impact on ecosystem functioning is suggested including their use as bio-fertilizers. The study was conducted from 2017 to 2023 in Northern Negev, Israel, at the PWA farm and Sayeret-Shaked LTER. The study aimed to determine the influence of TSs on soil fertility and explore its potential contribution to sustainable and profitable agriculture. The findings indicate that the local TSs contributed to a 2% increase in organic matter content, a significant 60% increase in Calcite-Magnetite, and up to six times higher levels of soluble Calcium and Magnesium compared to unaffected soil. An increase with a potential for CO2 inorganic sequestration. It is also indicated that successful agricultural utilization of TS relies on unmanaged rocky slopes for reproduction, designated migration paths for farmland access, and a unique cultivation approach to enhance decomposition. The finding may enable policymakers, and regional or government agencies to further invest in local ecosystems, and effective management tools for enhancing the reproduction of bio-fertilizers such as TS are also raised.

Identification of characteristics soil affected and not affected liquefaction at the north part of Petobo Village

On September 28th, 2018, an earthquake measuring 7.4 Mw shook Palu and its surroundings. The effects of this earthquake caused natural disasters, namely liquefaction. One of the areas of Palu City that was affected by liquefaction is located in Petobo Village. With Petobo's position in a relatively sloping area, this situation triggers landslides or landslides along with the liquefaction effect. This study aims to determine the characteristics and bearing capacity of the soil in the affected area and not affected by liquefaction, especially in the central part of the north avalanche. This study consisted of 2 test methods: field testing carried out with the Swedish Weight Sounding at 4 points in the affected area and 2 points in the area unaffected by liquefaction and laboratory testing including sieve analysis, Atterberg limits, direct shear and bulk density. The results of the field research show 3 parameters, namely Nsw, qa and qu. The value of Nsw in the affected area is in the range of 0 n/m-208.33 n/m, the value of qa is in the range of 30 kN/m2-196.67 kN/m2 and the value of qu is in the range of 45 kN/m2-201.25 kN/m2 while the area is not affected, the value of Nsw is in the range of 0 n/m-250 n/m, the value of qa is in the range of 30 kN/m2- 230 kN/m2 and the value of qu is in the range of 45 kN/m2-232.50 kN/m2. Soil classification results from laboratory tests on affected soils are SC (Clayey Sand) and unaffected soil, namely SC (Clayey Sand) and SM (Silty Sand). Based on the SWS parameter, the bearing capacity of the soil in the affected area is 32, 12 t/m2, and the non-affected area is 113, 70 t/m2. Based on the direct shear parameters, the soil bearing capacity in the affected area is 30, 54 t/m2 and the non-affected area is 136, 72 t/m2.

The Properties of Liquefiable Soil with Swedish Weight Sounding Test in BPTB (Agricultural Technology Research and Development Center) Office, Central Sulawesi

An earthquake measuring 7.4 MW in Central Sulawesi on 28th of September 2018, triggered liquefaction in several locations, one of them namely the BPTP office in Sigi district. The liquefaction that occurs causes massive sand boiling around the building, and a settlement in the foundation. This study aims to determine and compare the properties of land affected and not affected by liquefaction based on the Swedish weight sounding test, as well as the potential for liquefaction at the BPTP office location. The study consisted of 2 testing methods, namely field testing was carried out using the Swedish weight sounding test equipment at 3 points on the affected soil and 3 points on the unaffected soil, and laboratory testing including sieve analysis testing and Atterberg limits for 18 soil samples. The results showed that the Nsw value on the affected soil is in the range 4.00 n/m - 238.10 n/m, the Nsw value on the unaffected soil is in the range 26.00 n/m - 303.03 n/m, and groundwater level data obtained from the JICA Survey for Disaster Information Collection in Indonesia 2020 is at a depth of 5.31 meters below ground surface. The first section in your paper

The Study of Liquefied Soil by Using Swedish Weight Sounding Test in Jono Oge Village, Sigi Regency

The liquefaction that occurred on September 28, 2018, caused a massive lateral spreading in certain areas. This study aims to determine and compare the properties of land affected and not affected by liquefaction based on the Swedish Weight Sounding test, as well as the potential for liquefaction at Jono Oge village. The results of this study indicate that the laboratory test results show that the dominant soil classification on the affected and the unaffected soil is poorly graded sand silt (SP-SM). Whereas the results of field testing showed that the Nsw value on the affected soil is in the range 3,33 n/m – 263,16 n/m, the Nsw value on the unaffected soil is in the range 10,00n/m – 357,14 n/m, the qa value on the affected land is in the range up to 240,53 kN/m2, the qa value on the unaffected land is in the range of up to 315,71 kN/m2, the qu value on the affected land is in the range of 2.25 kN/m2 – 247,37 kN/m2, the qu value of unaffected land is in the range of 2.25 kN/m2 – 312,86 kN/m2.

Geochemistry study of soil affected catastrophically by tsunami disaster triggered by 2004 Indian Ocean earthquake using a fourth harmonics (λ = 266 nm) Nd:YAG laser induced breakdown spectroscopy

In this work, laser induced breakdown spectroscopy (LIBS) analysis of the soil samples collected from Aceh, a place in Indonesia worst affected by 2004 Indian Ocean tsunami, was conducted. In the LIBS experimental system, a high energy pulsed laser beam was focused on the tsunami affected soil samples and the atomic emission lines, originating from the laser induced plasma were recorded using locally developed laser induced breakdown spectrometer. Our results show that the concentrations of many elements especially terrestrial markers, namely titanium, iron, and carbonate marker such as magnesium, are higher in the tsunami-affected samples than that in the unaffected samples collected from the same neighborhood. The quantification of Ti, Fe and Mg were carried out using Ti II 334.94, Fe I 438.35, and Mg I 277.98 nm atomic transition lines respectively by drawing the calibration curve by preparing the samples of known concentrations in unaffected soil matrix. In order to ensure accurate quantification, the local thermal equilibrium of the laser-induced plasma was verified using Mc Writher criterion, for which the plasma temperature was estimated using linearized Boltzmann plot for six iron atomic transition lines and the electron number density in the plasma was estimated using Stark broadened Fe I 540.4 nm atomic lines. The estimated temperature and electron number density of the laser induced plasma are 9642 K and 3.5 × 10 16 cm −3 respectively. The concentrations of Ti, Fe and Mg in tsunami unaffected soil are 0.09, 3.2 and 0.02 w/w% and in tsunami affected soil are 0.14, 7.9 and 0.048 w/w% respectively. These values are in good agreement with XRF data. The elemental ratios extracted from LIBS signal intensity revealed that LIBS emission intensity ratios of several elements, such as Si/Ti, Al/Ti and Sr/Ba are potential candidates as the distinctive geochemical signature for identification the soil impacted and unimpacted by the 2004 Indian Ocean giant tsunami. The advantage of using LIBS for the elemental analysis is that the sample can be analyzed in its pristine form without any need cumbersome sample preparation method, which has the risk of bringing in external additives through chemicals used for the sample preparation. Other advantages of LIBS technique are that the analysis can be in situ and can be carried out remotely.

Why is Brachiaria decumbens Stapf. a common species in the mining tailings of the Fundão dam in Minas Gerais, Brazil?

Currently, more than five years after the Fundão dam failure in Mariana, Minas Gerais, Brazil, Brachiaria decumbens Stapf. is the main grass in pasturelands affected by the mining tailings. The aim of this study was to investigate the reason for this fact as well as to determine the ecophysiological effects of mining tailings on B. decumbens and to test whether mixing the tailings with unaffected local soil enhances the affected soil properties. For the experiment, two different soils were collected, one unaffected soil without mining tailings (Ref) and the mining tailings (Tec), and we also created a mixture with 50 % of each soil type (Ref/Tec). We cultivated B. decumbens in the three soil treatments in a greenhouse for 110 days and evaluated soil physical-chemical properties and plant ecophysiology. Our results show that the tailings (Tec) compromised the normal ecophysiological state of B. decumbens. The species survived these adverse conditions due to its great efficiency in acquiring some elements. The soil management tested by this work mitigated the stress caused by tailings and can represent an alternative for the environmental recovery of the affected soils.

Reallocation of nitrogen and phosphorus from roots drives regrowth of grasses and sedges after defoliation under deficit irrigation and nitrogen enrichment

Abstract Reallocation of nutrients from roots to shoots is essential for plant regrowth in grasslands, particularly in nutrient‐poor conditions. However, the response of root nutrient reallocation to changes in nitrogen (N) and water availability remains largely unknown. Using a novel 15N and 32P labelling technique, we quantified the contribution of N and phosphorus (P) to shoot regrowth from either root reallocation or direct soil uptake for perennial grasses exposed to high‐frequency deficit irrigation (HFDI) and N addition. Without N addition, HFDI showed no impact on uptake and reallocation of N and P, likely due to unaffected soil N availability and a greater diffusion barrier offsetting increased accumulation in plant‐available soil P. With N addition, HFDI increased plant N rather than P uptake, because of increasing soil N availability instead of P under combined HFDI and N addition. The HFDI decreased both N and P reallocation with N addition, possibly due to exhaustion of nutrient reserves in roots that were re‐allocated above‐ground. Reallocation contributed 48%–97% of N and 58%–79% of P required during the first 2 weeks of shoot regrowth. Synthesis. Our results highlight the importance of N and P reallocation from roots to buffer against changes in soil N and P availability and to maintain N:P ratio in shoot regrowth.

Effects of Se-Yeast on Immune and Antioxidant in the Se-Deprived Pishan Red Sheep.

The experiments were to study the effects of Se-yeast on immune and antioxidant in Selenium(Se)-deprived Pishan red sheep in Southern Xinjiang, China. The samples of soil, forage, and animal tissues were collected, and used for measuring mineral content, physiological parameter, and biochemical values. These findings showed that the Se contents in affected soil and forage were markedly lower than those from unaffected soil and forage (P < 0.01). Se in affected blood and wool were also extremely lower than those from healthy Pishan red sheep (P < 0.01). The hemoglobin, packed cell volume, platelet count, Glutathione peroxidase, and total antioxidant capacity in the affected Pishan red sheep were markedly lower than those from healthy ones too (P < 0.01). The levels of malondialdehyde, total nitric oxide synthase, and lipid peroxide in Pishan red sheep from affected pastures were extremely higher than those from healthy ones (P < 0.01). The levels of interleukin (IL)-1β, Interleukin-2, tumor necrosis factor-α and interleukin-6 from serum were markedly decreased in affected Pishan red sheep(P < 0.01). The Pishan red sheep in Se-deprived pasture were treated by orally with Se-yeast, the amount of Se in the blood markedly increased in treated animals. Meanwhile, the immune and antioxidant indicator was returned to the healthy values. Consequently, our findings were indicated that Se-deprived forage caused oxidative damage, and a serious threat to the immune function in animals. The Se-yeast is more effective in the Se-deficient Pishan red sheep including blood Se content, immune function and the antioxidant capacity.

Split-root approach reveals localized root responses towards apple replant disease (ARD) in terms of ARD biomarker gene expression and content of phenolic compounds

Apple replant disease (ARD) is a threat to apple fruit and tree production worldwide caused by shifts in the soil microbiome. Chemical and physical measures of soil disinfection are the most employed countermeasures but inter-row plantings demonstrate that ARD is widely immobile in the soil, which causes the plant to face ARD affected and healthy soil simultaneously in the field. We simulated this situation in a split-root approach and investigated the plant’s macroscopic and molecular reaction to localize its response. Root growth was severely reduced in two ARD soils. However, shoot growth was not proportionally reduced as long as half of the root system was growing in healthy soil. In ARD-affected roots, the expression of three ARD biomarker genes, biphenyl synthase 3, biphenyl 4-hydroxylase and ethylene-responsive transcription factor 1B-like, was locally induced after two weeks in comparison to disinfected ARD or control soil. Phenolic compound profiles in the roots were studied after eight weeks and showed a high variation between samples and soils. The total phenolic content as well as the contents of epicatechin and an unknown phenolic compound were locally increased in roots grown in ARD soil in comparison to disinfected ARD soil after eight weeks. Our results show how apple plants focus their molecular response towards ARD locally in the roots and are able to partly counteract the negative effects caused by ARD by growing into unaffected soil regions. The local nature of ARD presents both challenges in the assessment of ARD severity in the field and possible management strategies involving soil tillage.

A Comparative Analysis of Bioremediation of Hydrocarbon Polluted Soil in the Island Forest Ecosystem and the Low land Forest Ecosystem in the Niger Delta through Enhanced Natural Attenuation Process (ENAP)

The Niger Delta region has witnessed environmental pollution arising from oil activities over the years of oil exploration and production. Soil fertility in both the Lowland Forest Ecological Zone and Island Forest Ecological Zone were investigated to establish the consequences of oil pollution on the soil and remedial actions to restore back quality and fertility of the soil. A suitable cost effective and environmentally friendly technology to handle the pollutions in the Niger Delta region can be found in Remediation by Enhanced Natural Attenuation Process (ENAP) which facilitates the activities of microorganisms to biodegrade the hydrocarbon impacted soil. The study compared the bio-physicochemical parameters of the oil spill polluted soil with particular reference to areas of oil production of the two Ecological Systems with those of the unaffected soil as well as their response to bioremediation interventions using ENAP. The results demonstrated significant decrease in the values of the key indicator parameter, the Total Petroleum Hydrocarbons (TPH). But for the unenhanced process, the result showed low level of reduction of TPH values for the polluted soils. A degradation trend was demonstrated with time leading to significant TPH reductions and improved key soil fertility indices. The result showed that the level of the nutrient status of soil in the region can be improved through the natural attenuation process.

Molecular Barcoding Reveals the Genus Streptomyces as Associated Root Endophytes of Apple (Malus domestica) Plants Grown in Soils Affected by Apple Replant Disease

Apple replant disease (ARD) occurs when apple is repeatedly planted at the same site, leading to growth reductions and losses in fruit yield and quality. Up to now, the etiology has been poorly understood; however, soil (micro)biota are known to be involved. Because endophytes often colonize plants via the rhizosphere, this study aimed at comparing the bacterial endophytic root microbiome in plants growing in ARD-affected and unaffected soils from three different sites based on greenhouse biotests using a molecular barcoding approach. The initial endophytic microbiome of the starting material (in vitro propagated plants of the apple rootstock M26) did not significantly affect the overall richness and diversity of the endophytic community in plants after 8 weeks of growth in the respective soils but some genera of the initial microbiome managed to establish in apple roots. Proteobacteria was the dominant phylum in all samples. No differences in diversity or number of amplicon sequence variants (ASVs) between plants grown in ARD soil and unaffected soil was observed. However, several ASVs of high abundance uniquely found in plants grown in ARD-affected soils were Streptomyces spp. In soil from all three sites, these Streptomyces spp. were negatively correlated with plant growth parameters. Future inoculation experiments using selected Streptomyces isolates have to prove whether bacteria from this genus are opportunists or part of the ARD complex. For the first time, the bacterial endophytic community of apple roots grown in ARD-affected soils was characterized, which will help us to understand the etiology of ARD and develop countermeasures. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

Toxic metals in soil due to the land application of sewage sludge in China: Spatiotemporal variations and influencing factors

Land application has become a promising method for recycling energy and resources from sewage sludge; however, the changes that occur to the toxic metal concentrations in soil following the application of sewage sludge have been poorly investigated in China. The present study attempted to investigate the spatiotemporal variations of toxic metal concentrations in soil due to the land application of sewage sludge and the critical influencing factors. Overall, the results indicated that an increasing ratio of sewage sludge for land application, the concentrated disposal measures, and a shallower soil may lead to elevated toxic metal concentrations in soil. The worst scenario simulation showed that the cumulative discharge of toxic metals through sludge disposal were ranked as: Zn > Cu > Cr > Pb > Ni > As > Cd > Hg. After sewage sludge was applied to previously unaffected soil, i.e., background soil, the toxic metal concentrations in the soil increased annually over the period from 2006 to 2017. However, with respect to the affected soil, the concentrations of Zn and Cu increased, whereas the concentrations of As, Cd, Cr, and Pb decreased annually over the period from 2006 to 2017. The results indicate that, in practice, the selection of soil for sewage sludge disposal depends on the background and actual concentrations of toxic metals in a soil as well as the stress caused by the amount of sewage sludge application to cultivated land. We propose to use sewage sludge containing relatively lower concentrations of metals than the disposal soil for land application. Furthermore, land application of sewage sludge should be suited to local conditions in the future sewage sludge management.

Physical, chemical and microbiological characterization of the soils contaminated by iron ore tailing mud after Fundão Dam disaster in Brazil

The collapse of the Fundão dam in Mariana – Minas Gerais, in the Iron Quadrilateral, considerably modified the Carmo riverbank. This study aimed to perform a physical, chemical, and biological characterization of the soils contaminated by iron ore tailing mud after the dam disaster. From the riverbank to uncontaminated soil, three sites were sampled: site I (sandy sediment), site II (iron ore tailing mud) and site III (pasture soil). Analysis were performed to characterize soil physical features and soil fertility, fumigation-extraction method was applied to measure soil microbial biomass C, and to evaluate the photobiotic organisms' diversity by a growth experiment in a controlled chamber, for the samples collected in three sites. The results showed that site I presented quartz as the main mineral; site II presented both quartz and hematite; and site III presented greater diversity in the mineralogical composition. Site III showed greater fertility, except for the phosphorus and iron content that was higher in site II. The sites I and II have higher values of metabolic quotient and lower microbial carbon/organic carbon ratio, unlike site III. The results indicated that after one year of the dam failure the microbial activity was disturbed, as the nutrients and carbon concentration from the sites were decreased due to the presence of iron ore tailing mud in comparison to unaffected soil from the same area. However, a community of phototrophic microorganisms has been observed with a predominance of cyanobacteria, which may be important to enhance the development of this initial stage of succession.

Earthworm mucus contributes to the formation of organo-mineral associations in soil

Earthworms are considered as “ecosystem engineers” impacting soil properties as well as nutrient and element cycles. As they move through soil, earthworms secrete cutaneous mucus which is metabolized by soil microorganisms and a source of plant-available nutrients. Earthworm-processed soil contains carbon enriched, earthworm-specific soil aggregates (e.g. casts and middens) in comparison to earthworm unaffected soil. The reason could be that organic polymeric substances in earthworm mucus bind to soil minerals. The objective of this study was to investigate the small-scale interactions between earthworm mucus and secondary soil minerals, e.g. goethite and illite, leading to the formation of organo-mineral associations. We characterized the chemical composition of earthworm mucus by FTIR and 13C-NMR spectroscopy and compared spectra of mucus to microbial extracellular polymeric substances (EPS), an abundant and well-known type of organic matter that binds with soil minerals. Mucus from anecic (Lumbricus terrestris L.) and endogeic (Aporrectodea caliginosa Sav.) earthworm species was dominated by proteins and carbohydrates. Between 21 and 36% of the total organic carbon in the mucus containing treatments adsorbed to illite and goethite, and most of the binding with goethite was associated with phosphorus containing mucus compounds. The surface charge of newly-formed organo-mineral associations was determined by measuring the isoelectric point (IEP). The IEP of mucus-goethite associations was 6.8, which was lower than the bare goethite IEP of 8.4. The zeta potential of mucus-illite associations was greater than bare illite. We conclude that the specific adsorption of earthworm mucus constituents to soil minerals leads to the formation of mucus-mineral associations. These associations contribute to retention of organic substances from earthworm mucus in soil (micro-)aggregates and explain the altered physicochemical properties of earthworm-formed aggregates in comparison to the earthworm unaffected “bulk” soil material.

Effect of an acid mine spill on soils in Sonora River Basin: Micromorphological indicators

The role of soil could be decisive for the neutralization of the acid solution and immobilization of the metallic contaminants produced by mining industry. We studied micromorphological indicators of the interaction between the acid solution and soil material in the profile of Fluvisol at the Bacanuchi river (Sonora River Basin, Mexico) terrace affected by the catastrophic mine spill and in analyzing sample from a soil column treated with an acid liquid imitating the spill. Original unaffected soil is sandy with poorly developed pedogenetic features, however, frequent primary and secondary micritic and sparitic carbonates define high pH values. In the soil influenced by acid solutions under natural and laboratory conditions, carbonates were absent whereas neoformed gypsum crystals with radial intergrowth were observed together with accumulation of fine material enriched in ferruginous pigment. Micromorphometric quantification of the iron-rich fine material has shown its increase after interaction with the acid solution. We conclude that the interaction consisted of the neutralization reaction between the more reactive phases of the soil and the acid solution during which carbonates were consumed and gypsum was neoformed. Fine iron oxides precipitated after neutralization of acidity, the pH increased and the color changed. It is highly probable that other metallic contaminants co-precipitated with the ferruginous components.

Numerical modelling of transient soil temperature distribution for horizontal ground heat exchanger of ground source heat pump

A ground heat exchanger is the most important part of a ground source heat pump system. Soil properties and ground heat exchanger performance strongly depend on soil temperature profile and vary with time and space. Also, soil temperature profile is a function of heat transfer rate extracted or transferred to soil. Studies in the literature either use the unaffected soil temperature obtained from meteorological data or fail to run for long time periods to obtain a steady periodic soil temperature profile and over-predict the ground heat exchanger performance. Therefore, steady periodic temperature profile should be used for sizing ground heat exchanger for efficient operation of ground source heat pumps for longer periods of time. Experimental studies are carried out on a ground-source heat pump established at Yıldız Technical University, Davutpaşa Campus and the newly developed numerical model is validated with experimental results. For the numerical study, the hourly required heat load of a 200 m2 office in Istanbul during the heating season is calculated by using HAP software. The transient soil temperature profile is obtained numerically for longer periods of time with realistic boundary conditions using meteorological data. The fluid inlet temperatures equivalent to the hourly need for heating load of the office during the heating season are simulated for a ten-year period in accordance with the different heat amounts extracted from unit pipe length in soil (21, 10.5 and 7 W/m). The effects of burial depth, distance between pipes and surface effects on soil temperature are also investigated. Horizontal and vertical temperature distribution in soil at the beginning (November 10th), middle (January 21st) and end (April 3rd) of the first, fifth and tenth years are represented.

IMPACT ANALYSIS OF SOIL CONDITION POLLUTED WITH OIL SPILLAGE IN OTUJEREMI, DELTA STATE, NIGERIA

The implication of oil spillage is the degradation of land and water. Consequently, soil becomes infertile for farming and water un-potable for drinking. We investigated the impact of oil spillage on soil collected from depth of 150 cm. Soil affected and that not affected by crude oil spill from same geographical location were sampled and analyzed. Texturally, the soil is classified as fine, medium and coarse sandy and sandy loam. The sand fraction increased by 0.2% (86.174 to 86.414); silt by 53.5% (3.852 – 5.91) and clay decreased by 22.6% (9.916-7.672) when contaminated with petroleum. Physiochemical properties of pH(H20), pH(kcl), organic matter, organic carbon and nitrogen, exchangeable bases (Na+, K+, Mg+ and Ca3+), exchangeable acidity (Al3+, and H+), effective cation exchangeable capacity, phosphorus, heavy metals ( Pb3+, Fe2+, Ni+, V+, Cd3+, Cr3+ and Cu3+) were analyzed in the laboratory by standard methods and compared. The pH (H20) of the unaffected soil increased by 5.17% (5.85 to.5.00); pH (kcl) by 4.25% (4.7 to 4.50); organic matter by 264.92%; organic carbon by 356.7% and organic nitrogen by 311.19% when contaminated with petroleum. Exchangeable bases increased in values (Na+ by 80.94%, K+ by 126%, and Ca3+ by 11.75%) except Mg, whose value decreased by 65%; ECEC by 35%; P by 67.1%; exchangeable acidity by 7.83%. Heavy metals were also released into the soil upon contamination with petroleum; Pb2+ increased by 46% (1.4 to 2.044); Fe2+ by 25.96% (512.788 to 646.1); Ni+ by 19.11% (100.416 to 119.6); V+ by 80.26% (3.86 to 6.658), Cd3+ by 55% (2.772 to 4.324) and Cr3+ by 47.98% (2.528 to 3.741). There was significant positive correlation between heavy metals and pHkcl, organic matter, carbon and nitrogen.

Organic Carbon Analysis of Charcoal-Enriched Soils at Catoctin Mountain Park, MD

The application of charcoal to soils to increase carbon stocks has been of great interest recently. To gain a better understanding of the long-term effects of charcoal presence in soils, historic charcoal production sites at Catoctin Mountain Park, Maryland were studied for organic carbon content and compared to nearby unaffected soils. Soil organic carbon concentrations were measured through loss on ignition, and organic carbon stocks were calculated for fixed depths of 80 cm. Both the organic carbon concentrations and organic carbon stocks indicate that historically affected charcoal hearth soils contain more carbon compared to unaffected controlled soil samples. However, there is some variation in organic carbon content between charcoal hearths located in different landscape positions. Overall, charcoal application to soils may increase organic carbon stocks for extended periods of time, which can be of great importance for climate change mitigation and the enhancement of soil fertility.

The Investigation of &lt;sup&gt;137&lt;/sup&gt;Cs Contamination in Soils of Aceh after the Tsunami

Cs-137 is one of the most common radionuclides used for analysing man-made radioactive contamination in the environment beside Sr-90. Nangro Aceh Darussalam Province suffered the greatest mortality, with widespread destruction extending along more than 1000 km of coastline on 26 December 2004 due to tsunami. The disaster were affected areas about 220 km long and around 5 km wide along the coastlines of Aceh and North Sumatra. The purpose of this study is to investigate the artificial radioactivity 137 Cs in soil samples which have been collected from various locations along the areas affected by tsunami in Aceh. The surface soil samples were collected from 20 sites in this region. The soil samples from the middle area of Aceh which was not exposed to the tsunami have also been investigated for comparison. The activity concentration of 137 Cs in the samples was measured using a ORTEC P-type coaxial high purity Germanium (HPGe) detector system. The artificial radioactivity level of 137 Cs measured from these samples was found in the range of not detected to 2.09 Bq.kg -1 for the affected soil samples and 0.56 to 1.44 Bq.kg -1 for unaffected soil respectively. The radioactivity concentrations of 137 Cs within the coastline areas are comparable to that of the middle area, which was not exposed to the tsunami. The results indicate that there are no new inputs of man-made radionuclides into the area at that time and the data obtained could serve as baseline levels of 137 Cs in Aceh Region. Received: 29 May 2015 ; Revised: 02 November 2015; Accepted: 25 November 2015

Genomic and metagenomic analysis of microbes in a soil environment affected by the 2011 Great East Japan Earthquake tsunami.

BackgroundThe Great East Japan Earthquake of 2011 triggered large tsunami waves, which flooded broad areas of land along the Pacific coast of eastern Japan and changed the soil environment drastically. However, the microbial characteristics of tsunami-affected soil at the genomic level remain largely unknown. In this study, we isolated microbes from a soil sample using general low-nutrient and seawater-based media to investigate microbial characteristics in tsunami-affected soil.ResultsAs expected, a greater proportion of strains isolated from the tsunami-affected soil than the unaffected soil grew in the seawater-based medium. Cultivable strains in both the general low-nutrient and seawater-based media were distributed in the genus Arthrobacter. Most importantly, whole-genome sequencing of four of the isolated Arthrobacter strains revealed independent losses of siderophore-synthesis genes from their genomes. Siderophores are low-molecular-weight, iron-chelating compounds that are secreted for iron uptake; thus, the loss of siderophore-synthesis genes indicates that these strains have adapted to environments with high-iron concentrations. Indeed, chemical analysis confirmed the investigated soil samples to be rich in iron, and culture experiments confirmed weak cultivability of some of these strains in iron-limited media. Furthermore, metagenomic analyses demonstrated over-representation of denitrification-related genes in the tsunami-affected soil sample, as well as the presence of pathogenic and marine-living genera and genes related to salt-tolerance.ConclusionsCollectively, the present results would provide an example of microbial characteristics of soil disturbed by the tsunami, which may give an insight into microbial adaptation to drastic environmental changes. Further analyses on microbial ecology after a tsunami are envisioned to develop a deeper understanding of the recovery processes of terrestrial microbial ecosystems.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2380-4) contains supplementary material, which is available to authorized users.