Spatial distribution of soil organic carbon quality descriptors determining factors that affect its sequestration in Northeast Algeria.

Increasing soil organic carbon (SOC) content is crucial for soil fertility, conservation, and combating climate-related issues by sequestering CO. While existing studies explore the total content of SOC, few of them investigate the factors that favor its sequestration and the impact of land use type and management. This research aims to study the spatial variation of the total content and the quality or maturity (in terms of aromaticity) of the humic acid (HA) fraction, along with the factors that enhance its formation and conservation for a longer time in the soil.

Impact of Biochar Amendment on Soil Properties and Organic Matter Composition in Trace Element-Contaminated Soil.

The application of biochar as an organic amendment in polluted soils can facilitate their recovery by reducing the availability of contaminants. In the present work, the effect of biochar application to acid soils contaminated by heavy metal spillage is studied to assess its effect on the quantity and composition of soil organic matter (SOM), with special attention given to soil humic acids (HAs). This effect is poorly known and of great importance, as HA is one of the most active components of SOM.

Hydrophobicity of soils affected by fires: An assessment using molecular markers from ultra-high resolution mass spectrometry.

Soil water repellency (SWR) is a physical property due to a complex interaction of factors (e.g., fire, soil organic matter, soil texture) that reduces the soil water infiltration capacity.

Fire effects on C and H isotopic composition in plant biomass and soil: Bulk and particle size fractions.

This work studies carbon (C) and hydrogen (H) isotope composition of plant biomass and soil organic matter (SOM) in an attempt to assess both, changes exerted by fire and possible inputs of charred materials to the soil after a wildfire. Isotope composition of bulk soil, soil particle size fractions and biomass of the dominant standing vegetation in the area (Quercus suber) from Doñana National Park (SW-Spain) were studied by isotope ratio mass spectrometry (IRMS). SOM C isotope composition indicates the occurrence of two SOM pools with different degree of alteration.

Effect of a wildfire and of post-fire restoration actions in the organic matter structure in soil fractions.

The impact of wildfires and of restoration actions on soil organic matter (SOM) content and structure was studied in a soil under pine (Pinus pinea) from Doñana National Park (SW Spain). Samples were collected from burnt areas before (B) and after post-fire restoration (BR) and compared with an unburnt (UB) site. Analytical pyrolysis (Py-GC/MS) was used to investigate SOM molecular composition in whole soil samples and in coarse (CF) and fine (FF) fractions.

Thallium and co-genetic trace elements in hydrothermal Fe-Mn deposits of Central Spain.

Thallium (Tl) is a hazardous trace metal that can harm human and environmental health. Tl pollution can result from the mining and smelting of Tl-bearing minerals, but also the natural weathering of Tl-bearing sulfide minerals may induce Tl release to the environment. In this study, hydrothermal deposits hosted in dolostone rocks sited along fossil thermal springs in the Lodares region (Soria province, central Spain) were studied.

Quantitative forecasting black (pyrogenic) carbon in soils by chemometric analysis of infrared spectra.

A detailed and global quantitative assessment of the distribution of pyrogenic carbon (PyC) in soils remains unaccounted due to the current lack of unbiased methods for its routine quantification in environmental samples. Conventional oxidation with potassium dichromate has been reported as a useful approach for the determination of recalcitrant C in soils. However, its inaccuracy due to the presence of residual non-polar but still non-PyC requires additional analysis by C solid-state nuclear magnetic resonance (NMR) spectroscopy, which is expensive and time consuming.

Chemometric assessment of soil organic matter storage and quality from humic acid infrared spectra.

The knowledge of biogeochemical mechanisms involved in soil organic carbon (SOC) storage is crucial to control its release to the atmosphere. In particular, the chemical composition of soil organic matter (SOM) plays an important role in the performance of the C storage and resilience in soils. The structural information provided by infrared spectroscopy (IR) of soil humic acid (HA) was used in the assessment of the C storage potential of 35 Spanish soils.

Mulching-induced preservation of soil organic matter quality in a burnt eucalypt plantation in central Portugal.

Mulching has amply proven its effectiveness to mitigate post-fire soil erosion but its impacts on soil organic matter (SOM) quality and quantity continue poorly studied. The present study addressed this knowledge gap for a eucalypt plantation in central Portugal that had been burnt and, immediately after the wildfire, mulched with 13.6 Mg ha of eucalypt logging residues some five years before.

Soil Perturbation in Mediterranean Ecosystems Reflected by Differences in Free-Lipid Biomarker Assemblages.

Environmental information provided by free lipids in soil samples collected from control and disturbed plots (Madrid, Spain) was assessed by comparing molecular assemblages of terpenoids and distribution patterns of alkanes and fatty acids (FAs) analyzed by gas chromatography-mass spectrometry (GC-MS). Wildfires in pine forests led to increased proportions of retene, dehydroabietin, and simonellite. Friedo-oleananes were characteristic in soils under angiosperms, and norambreinolide-type diterpenes were characteristic in soils encroached by Cistus bushes.

Ultra-high resolution mass spectrometry of physical speciation patterns of organic matter in fire-affected soils.

Fire is one of the most important modulating factors of the environment and the forest inducing chemical and biological changes on the most reactive soil component, the soil organic matter (SOM). Assuming the complex composition of the SOM, we used an ultra-high resolution mass spectrometry analysis technique to assess the chemical composition and fire-induced alterations in soil particle size fractions (coarse and fine) from a sandy soil in a Mediterranean oak forest at Doñana National Park (Southwest Spain). Electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) showed that the coarse fraction of soils not affected by fires consisted mainly of polyphenolic compounds consistent with little-transformed SOM and fresh biomass, whereas the fine fraction was enriched in protein and lipid like homologues suggesting microbially reworked SOM.

Graphical statistical approach to soil organic matter resilience using analytical pyrolysis data.

Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) of humic acids (HAs) from 30 agricultural soils from a volcanic island (Tenerife, Spain) was used to discern the molecular characteristics of soil organic matter (SOM) associated to resilience. For faster perceptual identification of the results, the yields of the pyrolysis products in the form of surface density plots were compared in an update of the Van Krevelen graphical statistical method. This approach, with respect to data reduction and visualization, was also used to collectively represent statistical indices that were obtained after simple and partial least squares (PLS) regression.

The diversity of methoxyphenols released by pyrolysis-gas chromatography as predictor of soil carbon storage.

The variable extent to which environmental factors are involved in soil carbon storage is currently a subject of controversy. In fact, justifying why some soils accumulate more organic matter than others is not trivial. Some abiotic factors such as organo-mineral associations have classically been invoked as the main drivers for soil C stabilization.

Post-fire recovery of soil organic matter in a Cambisol from typical Mediterranean forest in Southwestern Spain.

Wildfire is a recurrent phenomenon in Mediterranean ecosystems and contributes to soil degradation and desertification, which are partially caused by alterations to soil organic matter (SOM). The SOM composition from a Cambisol under a Mediterranean forest affected by a wildfire is studied in detail in order to assess soil health status and better understand of soil recovery after the fire event. The soil was sampled one month and twenty-five months after the wildfire.

Compound-specific stable carbon isotopic signature of carbohydrate pyrolysis products from C3 and C4 plants.

Background: Pyrolysis-compound specific isotopic analysis (Py-CSIA: Py-GC-(FID)-C-IRMS) is a relatively novel technique that allows on-line quantification of stable isotope proportions in chromatographically separated products released by pyrolysis. Validation of the Py-CSIA technique is compulsory for molecular traceability in basic and applied research. In this work, commercial sucrose from C4 (sugarcane) and C3 (sugarbeet) photosystem plants and admixtures were studied using analytical pyrolysis (Py-GC/MS), bulk δ(13)C IRMS and δ(13)C Py-CSIA.

Pyrolysis-gas chromatography-isotope ratio mass spectrometry of polyethylene.

Polyethylene is probably the most used plastic material in daily life and its accurate analysis is of importance. In this communication the chemical structure of polyethylenes is studied in detail using conventional analytical pyrolysis (Py-GC/MS), bulk stable isotopic analysis (IRMS) and pyrolysis compound specific stable isotopic analysis (Py-CSIA) to measure stable isotope proportions (δ(13)C, δ(15)N and δD) of polyethylene pyrolysis compounds. Polyethylene pyrolysis yields triplet peaks of n-alkanes, α-alkenes and α,ω-alkanedienes.

Evolution of organic matter fractions after application of co-compost of sewage sludge with pruning waste to four Mediterranean agricultural soils. A soil microcosm experiment.

The effect of co-compost application from sewage sludge and pruning waste, on quality and quantity of soil organic carbon (SOC) in four Mediterranean agricultural soils (South Spain), was studied in soil microcosm conditions. Control soil samples (no co-compost addition) and soils treated with co-composts to a rate equivalent of 140 Mg ha(-1) were incubated for 90 days at two temperatures: 5 and 35 degrees C. The significances of incubation temperature and the addition of co-compost, on the evolution of the different fractions of SOC, were studied using a 2(3) factorial design.

Solid-phase micro-extraction (SPME) in the early detection of potentially active volatile compounds from organic wastes used for the management of soil-borne pathogens.

The complex molecular assemblages were analysed in the soil gas phase after applying pine forest wastes (PFW) or sugarbeet vinasses (SBV) for soil-borne crop pests' management. For this purpose, solid-phase micro-extraction (SPME) and gas chromatography (GC) were used coupled with mass spectrometry (MS). The organic wastes were applied either to Calcic Entisol or Haplic Arenosol moistened at field capacity and soil was covered with polyethylene sheet for 28-30 days to retain the volatiles.

Bioreactor treatment of municipal solid waste landfill leachates: characterization of organic fractions.

Quantitative and qualitative changes in organic matter were studied at different stages of treatment in a bioreactor designed to process leachates from a municipal solid waste landfill. The particulate matter (PM) and macromolecular fractions of the dissolved organic matter with solubility properties comparable to humic (acid-insoluble) and fulvic (acid-soluble) acid fractions (AI, AS, respectively) from the incoming black liquid, the bioreactor content, and the final processed effluent were isolated, quantified, and characterized by visible and infrared (IR) spectroscopies. The macromolecular signature either aliphatic (glycopeptides, carbohydrates) or aromatic (coinciding with infrared patterns of lignin, tannins etc.

Multivariate statistical analysis of mass spectra as a tool for the classification of the main humic substances according to their structural and conformational features.

The aim of this work is to explore the suitability of the complementary use of mass spectra and the corresponding statistical analysis (principal components-Pareto analysis (PCA) and discriminant analysis (DA)) of these spectra to differentiate diverse humic samples as a function of their structural and conformational features. To this end, the mass spectra of humic samples belonging to the main humic fraction types (gray humic acid, brown humic acid, and fulvic acid) were obtained by electrospray ionization mass spectrometry (ESI-MS). The results obtained showed that the application of PCA yielded a clear separation between blanks and humic samples.

Evaluation of soil biodesinfestation with crop and garden residues in the control of root-knot nematodes populations.

Fresh crop and garden residues were applied both under laboratory conditions and in commercial greenhouse in order to asses their effect on soil nematodes populations and soil fertility. In the laboratory experiments, dosages of 5 to 20 g of cabbage residues, chicken manure, cabbage residues+chicken manure, grass+chicken manure, as well as leaves and stems of orange tree, pine tree, oleander, olive tree, palm tree and boxwood were mixed with 500 g soil having root-knot nematodes (Meloidogyne incognita) and soil moisture was adjusted at field capacity. A control treatment without residues was also included.

Raw or incubated olive-mill wastes and its biotransformed products as agricultural soil amendments-effect on sorption-desorption of triazine herbicides.

Raw olive-mill waste and soil amendments obtained from their traditional composting or vermicomposting were added, at rates equivalent to 200 Mg ha-1, to a calcareous silty clay loam soil in a laboratory test, in order to improve its fertility and physicochemical characteristics. In particular, the effects on the sorption-desorption processes of four triazine herbicides have been examined. We found that comparatively hydrophobic herbicides terbuthylazine and prometryn increased their retention on amended soil whereas the more polar herbicides simazine and cyanazine were less affected.

Sorption-desorption of alachlor and linuron in a semiarid soil as influenced by organic matter properties after 16 years of periodic inputs.

The effect of management practices on soil potential for regulating the residual concentration of pesticides was examined in samples from a Calcic Haploxeralf in Toledo (central Spain). Sorption-desorption of alachlor and linuron was found to depend on inputs of lignocelullosic wastes or cattle manure for the past 16 years. For a given herbicide, the soil sorption capacity (K(f)) follows the order control < crop residues < manure, which is consistent with the organic C content in the soil samples.

Analysis of carbon and nitrogen forms in soil fractions after the addition of 15N-compost by 13C and 15N nuclear magnetic resonance.

A quantitative laboratory assessment of the different C and N forms in soil humus fractions was carried out by incubation of a mineral substrate after the addition of (15)N-labeled compost. The experimental design included (i) preparation of the (15)N-labeled organic matter (city refuse compost, 640 g kg(-1) wheat straw and K(15)NO(3) composted for 80 days), (ii) a further 80 day incubation of a mixture of the labeled compost with a mineral soil (32 g kg(-1)), (iii) measurement of stable isotope ratios, and (iv) isolation and structural comparison by (13)C and (15)N cross-polarization, magic-angle spinning nuclear magnetic resonance (NMR) of different organic fractions, i.e.