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Low-intensity burnings could be an effective silvicultural tool to prevent the occurrence and severity of wildfires. Nevertheless, their use as a forest fuel reduction tool may have a negative impact on soil properties. The aim of this investigation was to study the impact of a low-intensity prescribed fire on the main chemical properties of the soil (pH, electrical conductivity, and total organic carbon), and the diversity and composition of the soil bacterial communities in a semi-arid forest in SE Spain. Two similar stands were treated with a low-intensity prescribed burn in spring and autumn 2018 and were compared to an unburned stand. All soil samples were collected at the same time (autumn 2018). The chemical properties of the soil showed no significant differences between the prescribed burns and the control forest. Shannon and Pielou's diversity indices presented values significantly lower in the burned soils compared to the control. Prescribed burning did not modify soil bacterial community structure at the phylum level, but NMDS analysis did reveal a difference between soil bacterial communities at the genus level. Both prescribed burnings favoured some bacterial taxa over others, suggesting different thermal and bacterial resistance. The presence of Massilia, Pseudomonas and Arthrobacter could suggest a short-term ecosystem recovery. Therefore, prescribed burning in semi-arid forests could be suitable as a preventive tool against wildfires. [ABSTRACT FROM AUTHOR]

The restoration of unproductive abandoned agricultural soils under a semi-arid climate in southeastern Spain was evaluated. Four organic amendments from different composted wastes (greenhouse crop residues; worm compost from sheep–cow manure and plant remains; chicken manure; and sheep–chicken manure and plant remain) were applied, untreated control plots were installed, and natural unexploited soils were selected as a reference ecosystem. Through three sampling campaigns (initial, 3 months, and 12 months), significant changes were observed in soil physico-chemical properties, nutrient content (carbon -C-, nitrogen -N-, and phosphorus -P-), and bacterial composition of the restored soils with respect to control and natural soil, especially at 3 months. The increase of labile nutrients caused the proliferation of copiotrophic phyla at 3 months, which, after their consumption, were replaced by oligotrophic phyla at 12 months. Specific taxa involved in C, N, and P cycles were identified for each soil. For the soil bacterial composition of vermicompost, only chicken and sheep–chicken manures were more dissimilar to control and natural soils after 12 months, while greenhouse crop compost showed an intermediate position between them. Results indicated that composted greenhouse crop remains could be an optimal treatment for the short-term recovery of physico-chemical properties, nutrient content, and bacterial composition of agriculture-degraded soils in semi-arid areas. [ABSTRACT FROM AUTHOR]

The objective of our study was to undestand the effect of two organic amendments on three planted autochthonous species in two substrates mulched with pine chips 6 years after starting an experimental restoration in a quarry for cement production in semiarid SE Spain. But because this kind of mulch contained pine cones and pine seedlings appeared after the first year of the restoration, new objectives were added to the initial one: to check if organic amendments influenced pine growth among planted vegetation and if there were competition between planted and non‐planted species. Essential soil parameters, plant cover and diversity and pine growth were measured and statistically processed with correlation analyses, ANOVA and detrended correspondence analysis. Six years after restoration, organic amendments contributed significantly to explain the differences on the tested variables. The combined effects of the two substrates and the two organic amendments effectively enhanced soil properties recovery, but they also facilitated the establishment and entry of new species in addition to planted vegetation, driving a differential plant development. Planted vegetation cover and total plant cover from amended plots were double that of control plots. The number of pines, as well as their coverage, depended on the interaction between amendment type and substrate. Organic amendments favoured opportunistic species which, despite competing with those planted, helped to control soil erosion and enhanced pedogenesis. Pine chips used as mulch and derived pine seedlings, despite not entering the experimental design, might have some potential in the restoration of these particular degraded semiarid environments. [ABSTRACT FROM AUTHOR]

Although several management options are adopted to redirect post-fire forest ecosystems towards less vulnerable and more resilient and functional communities, little is known about the interactions among tree stand age, pre-fire forest management, and slope aspects, and their consequences for plant species and soil properties recovery immediately after severe wildfires. To address this knowledge need, this study evaluates the post-fire changes in species richness and diversity (with a specific focus on regeneration mechanisms and life forms) of regenerating plants as well as the main physico-chemical and biological properties of burned soils with the reciprocal relations. Plant cover and diversity, and many soil properties have been monitored in forests of southeast Spain with mature, middle and young stands, presence of pre-fire treatments or not, and north and south hillslopes about one year after the fire. To this aim, the reciprocal relationships among soil properties and plants were evaluated adopting a combination of statistical techniques (PERMANOVA, Non-metric Multi-Dimensional Scaling, Distance-based Linear Modelling, Distance-based Redundancy Analysis, and Spearman correlation analysis). The damage to soil and vegetation was so high that both plants and pre-fire soil properties slowly recovered. Only a few life forms of vegetation (geophytes and herbaceous chamaephytes) were influenced by the stand age. If combined with soil aspect, stand age resulted in significantly lower germinating species in mature stands and lower resprouters in young stands, both on south hillslopes. Plant diversity was high, and the post-fire regeneration did not change the species richness and evenness. The post-fire changes in soil properties were limited, and only slight small differences in pH and betaglucosidase among stands of different age were found. No evident associations between soil properties and plant diversity were revealed by the low correlation coefficient. The low variance in plant cover and diversity, as well as in soil properties, resulted in a low accuracy of the dbRDA model to reproduce its variability among sites with different pre-fire characteristics. • An extremely high fire severely damaged soil and vegetation, which both slowly recovered. • Stand age resulted in lower germinating species in mature and south-aspect stands. • Stand age yielded lower resprouters in young stands on south hillslopes. • Post-fire regeneration did not change species richness and evenness. • Post-fire changes in soil properties were limited (except for pH and betaglucosidase). [ABSTRACT FROM AUTHOR]

Abstract: Soil physical and chemical characteristics as well as climatic and geomorphological factors have been determined in 68 sites of a mountain calcimorphic ecosystem (Sierra María-Los Vélez Natural Park, Almería) in Southeastern Spain. Land use and vegetation were natural pine forest, evergreen oak forest, reforested pine forest of different ages, bush, juniper forest, and olive, almond and cereal crops under conventional tillage. By using multivariate data treatments, 17 soil variables were processed. A large part of the total variability was controlled by local topographical features through their effect on moisture retention and vegetation. Most characteristics were significantly correlated with total organic C (mean=28.5±4.6 g kg−1), which demonstrates the central role of the organic matter in the functioning of the whole ecosystem. New soil quality descriptors consisting of ratios to soil organic carbon were obtained, informing about the specific activity (per C unit) or performance of the organic matter, independently of its total content. When soil data are directly processed by using principal component analysis, we found a set of high quality soils under natural and old reforested forests, where environmental services provided by soil depend on the high levels of quality descriptors related to organic carbon, e.g. cation exchange capacity (CEC), total porosity, or aggregate stability. When variables such as CEC, porosity and aggregate stability are calculated as ratios to the total organic carbon, a new classification pattern is obtained, allowing to detect soils with organic matter of high maturity which in general do not coincide with soils with high organic matter content. The results suggest the assessment of soil quality based on ratios informing on the organic matter performance should be emphasized as an alternative to direct descriptors based on the total organic carbon content. [Copyright &y& Elsevier]

Abstract: Water and nutrients are scarce resources in arid and semiarid ecosystems. In these regions, biological soil crusts (BSCs) occupy a large part of the soil surface in the open spaces surrounding patches of vegetation. BSCs affect physicochemical soil properties, such as aggregate stability, water retention, organic carbon (OC) and nitrogen (N) content, associated with primary ecosystem processes like water availability and soil fertility. However, the way BSCs modify soil surface and subsurface properties greatly depends on the type of BSC. We hypothesised that physicochemical properties of soil crusts and of their underlying soils would improve with crust development stage. Physicochemical properties of various types of soil crusts (physical crusts and several BSC development stages) and of the underlying soil (soil layers 0–1 cm and 1–5 cm underneath the crusts) in two semiarid areas in SE Spain were analysed. The properties that differed significantly depending on crust development stage were aggregate stability, water content (WC) (at −33 kPa and −1500 kPa), OC and N content. Aggregate stability was higher under well-developed BSCs (cyanobacterial, lichen and moss crusts) than under physical crusts or incipient BSCs. WC, OC and N content significantly increased in the crust and its underlying soil with crust development, especially in the first centimetre of soil underneath the crust. Our results highlight the significant role of BSCs in water availability, soil stability and soil fertility in semiarid areas. [Copyright &y& Elsevier]

Soils are considered as a major reservoir for terrestrial carbon and it can act as a source or sink depending upon the land management activities. In semi-arid areas, the natural recovery of soils degraded by mining activities is complicated. A possible solution to recover soil quality and functionality, plant cover and carbon sequestration capacity could be the application of organic amendments. This work focuses on a restoration carried out in 2018 by applying with different composted organic amendments (stabilized sludge, gardening and greenhouse waste) in a limestone quarry under semi-arid climate (SE Spain). The objective was to evaluate the effects of different organic amendments on net CO 2 exchange in two microcosms: soil- Stipa tenacissima and soil-spontaneous vegetation. Soil physical and chemical properties, environmental and ecological variables and their interrelationship were studied in amended and unamended soils. The results obtained under soil-forming factors in the study area showed an increase in soil organic carbon and nitrogen content, improved moisture and plant growth, and plant canopy development in amended soils. Soil moisture, soil temperature and plant cover significantly influenced net CO 2 exchange. In general, microcosms with S. tenacissima showed higher carbon sequestration rates than soils with only spontaneous plant cover. Soils treated with a vegetable-only amendments showed higher plant cover and CO 2 fixation rates after significant rainfall. On the other hand, the plots treated with sludge compost presented more soil respiration than photosynthesis, especially in the wet seasons. Soils with sludge and greenhouse compost mixed had higher CO 2 fixation rates than soils restored with a mixture of sludge and garden compost. Soils with greenhouse waste compost showed CO 2 fixation in the microcosm with plants in all campaigns, being the best treatment to promote atmospheric CO 2 sequestration in soil restoration. [Display omitted] • Restoration of mining soils with organic amendments improved CO2 fixation. • CO2 uptake was higher in soils with resilient with vegetable greenhouse crop compost after rain pulses. • Greenhouse compost showed highest CO2 sequestration potential. • Organic amendments promoted plant growth and spontaneous plant cover development. [ABSTRACT FROM AUTHOR]

Mediterranean humid mountains are ecological hotspots with high water availability that may accelerate their recovery after farmland abandonment, a widespread phenomenon in marginal areas of the European Mediterranean Region. This land use change led to secondary succession processes triggering changes in soil properties and soil microorganisms. This is the first study in assessing the environmental influence of both ecological succession and parent material over soil properties and soil bacterial communities in these habitats. To examine the effects of secondary succession and elucidate the role of parent material in soil bacterial communities, six soil plots were sampled from the combination of abandoned and rainfed olive groves, terraced or non-terraced, and over four parent materials in Lluc Valley, a Mediterranean hyper-humid mountainous area on the island of Mallorca, Spain. Soil bacterial diversity and taxonomic composition at phylum and family level in each field were analyzed by rRNA 16 S amplicon sequencing. In addition, a series of soil physicochemical and microbiological properties, together with enzyme activities were assessed. Results showed that secondary succession and parent material significantly affected soil physicochemical and microbiological properties, soil enzyme activities and soil bacterial communities' diversity and taxonomic composition. Secondary succession following farmland abandonment triggered higher total organic carbon (TOC), microbial biomass carbon (C mic), basal soil respiration (REB), alkaline phosphatase activity (Php) and dehydrogenase activity (DHA), thus enhancing soil quality. In contrast, parent material significantly shaped pH, specific surface area (SSA), TOC, C mic , REB and soil enzyme activities, playing a key role in land use effects modulation. According to the distance-based redundancy analysis (db-RDA), SSA, TOC, REB, C mic , urease activity (Ur) and Php were the soil properties that contributed to significant changes in bacterial communities' composition at the family level. This study evidenced that farmland abandonment led to improve soil quality in Mediterranean humid mountains, with positive feedbacks provided by parent material. • Farmland abandonment triggered higher TOC, C mic and REB, enhancing soil quality. • Lithology significantly shaped pH, SSA, TOC, C mic , REB and soil enzyme activities. • β-diversity analyses showed changes due to secondary succession and parent material. • Significant relationships were found between soil properties and bacterial families. [ABSTRACT FROM AUTHOR]

One strategy for restoring degraded soils by opencast mining in semiarid regions is the application of organic amendments. However, selecting an appropriate organic amendment that improves soil quality and functionality for recovery in the short-term without a high contribution to increased CO₂ emissions is important for improving restoration strategies. Therefore, the objective of this work was to study the short and medium-term changes in physico-chemical and biological properties in restored soils with organic amendments from a limestone quarry (SE, Spain). Several restoration treatments were applied consisting stabilized sewage sludge, vegetable compost garden waste, vegetable compost from greenhouse crop residues and two mixtures thereof, then native plants were planted. After six months several soil properties were evaluated (electrical conductivity (EC), pH, total organic carbon (TOC), total nitrogen (TN), assimilable phosphorus (AP), soil water retention, carbohydrates and polyphenols content, enzymatic activities, bacteria and fungi fatty acids and soil respiration). Some physico-chemical soil properties and the survival rates and biovolume of the introduced native plants, as well as the percentage of land cover occupied by wild plants, were also analyzed 2 years after the application of the amendments. Organic amendments improved significantly all soil properties compared with unamended soils. Labile organic matter forms (carbohydrates and polyphenols) showed significant positive correlations with parameters related to microbial activity. Restored soils with sewage sludge had the highest significant labile C values, following by its mixtures. All organic amendments increased in situ CO₂ release, a positive priming effect and organic matter mineralization, being these properties higher in sludge-treated soils than in the rest restored and non-amendment soils. The content of TOC and TN and water retention remained similar two after the application of the amendments, but the EC decreased in restored soils. Nevertheless, despite PCA analysis clearly demonstrated that all restoration treatments had an important effect on the functionality and soil quality, vegetable compost from garden waste or from horticultural greenhouse crop waste amendments were the best restoration treatments for short and medium-term restoration of degraded quarry soils in harsh environmental and climate conditions because they also presented lower CO 2 emission rates to the atmosphere and the highest survival and growth rates of the introduced plants and wild cover in the experimental plots. • Organic amendments modify the physico-chemical properties in restored soil • Labile fraction of carbon stimulates the bacterial biomass and enzyme activities • Organic amendments increase soil quality and soil functionality • Organic amendments promote positive priming effect after application • High content of labile organic matter in organic amendment increased CO₂ emissions [ABSTRACT FROM AUTHOR]

Traditional management practices, such as grazing, can have adverse impact on soils. Despite an extensive body of literature exploring the effects of grazing on soil and plants worldwide, there is a notable lack of research on its impacts in Mediterranean forests within the Iberian Peninsula Furthermore, there is a knowledge gap on the enzymatic activities and basal respiration of soil in forest after grazing. To address these gaps, this study aimed to investigate the impact of grazing on various important physicochemical and biological soil properties along with vegetation richness in a Mediterranean forest located in Castilla-La Mancha (Central Eastern Spain). Relative to undisturbed sites, grazing significantly reduced soil water content (-53%) and available water (-59%). However, soil hydraulic conductivity remained unaffected by animal trampling and the soil water repellency observed in ungrazed sites disappeared. Grazed soils experienced a slight increase in pH (+18%). Among the biochemical properties studied, only dehydrogenase showed a significant increase (+100%) while basal respiration exhibited a notable decrease (-24%). Grazing resulted in a reduction of plant species richness (-34%) indicating a loss of biodiversity in grazed areas. The observed significant alterations in key soil and plant properties due to livestock activity suggest that grazing has the potential to modify the overall soil quality of these sites. Certain variables that exhibited noteworthy differences between grazed and ungrazed sites could serve as indicators of grazing impacts in Mediterranean forests. These indicators may be considered proxies for establishing effective land management strategies to mitigate degradation in the Mediterranean forest ecosystem., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study evaluate the effects of four organic soil amendments on soil. Physical, chemical and biochemical properties were compared to untreated and natural (not cultivated) soils in a semiarid region (Andalusia, Spain). A large set of physical, chemical biochemical properties and, the composition of bacterial communities; and overall soil quality index (SQI) were evaluated on soils treated with organic soil amendments of animal origin (compost from sheep and cow manure [CS] or chicken manure, [CK], vegetal origin (greenhouse crop residues [CC]), and vermicompost (CV). Immediately after application, the animal origin compost significantly increased pH, electrical conductivity (EC), and total nitrogen (TN) as well as the enzymatic activities associated with the carbon (C) cycle but decreased the richness and evenness of bacterial communities. After 3 months of treatment, all measured properties recovered except for EC, TN and dehydrogenase activity (whose increase was stable over time), as did bacterial richness, which remained lower. The vegetal-originating compost increased EC and pH whereas the other effects were not significant throughout the monitoring period. CV application did not affect soil properties. The SQI was the highest for soils treated with CK compost, both immediately after application and over time. The soil treatments with the other organic amendments did not result in a significantly different SQI over time compared to both untreated and natural sites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Current research on the influence of environmental and physicochemical factors in shaping the soil bacterial structure has seldom been approached from a pedological perspective. We studied the bacterial communities of eight soils selected along a pedogenic gradient at the local scale in a Mediterranean calcareous mountain (Sierra de María, SE Spain). The results showed that the relative abundance of Acidobacteria, Canditate division WPS-1, and Armatimonadetes decreased whereas that of Actinobacteria, Bacteroidetes, and Proteobacteria increased from the less-developed soils (Leptosol) to more-developed soils (Luvisol). This bacterial distribution pattern was also positively correlated with soil-quality parameters such as organic C, water-stable aggregates, porosity, moisture, and acidity. In addition, at a lower taxonomic level, the abundance of Acidobacteria Gp4, Armatimonadetes_gp4, Solirubrobacter, Microvirga, Terrimonas, and Nocardioides paralleled soil development and quality. Therefore, our work indicates that the composition of bacterial populations changes with pedogenesis, which could be considered a factor influencing the communities according to the environmental and physicochemical conditions during the soil formation.

Objective: To validate the Spanish version of the Children's Eating Attitudes Test (ChEAT)., Method: The factor structure and other psychometric characteristics of the questionnaire were examined using the answers of 38,554 schoolchildren. Diagnostic efficiency was based on a standardized clinical interview of 968 schoolchildren who had previously completed the questionnaire., Results: Five factors ("preoccupation with thinness," "dieting," "social pressure to eat," "purging," and "preoccupation with food and oral control") explained 46% of the variance. Cronbach's α was .858 for the total scale. The area under the receiver operating characteristic curve was .851. Sensitivity (SE) was 27% and specificity (SP) 96% for a cut-off of 20. A more appropriate cut-off was 15, where SE and SP were 62% and 90% respectively, and the positive and negative predictive values 27 and 98%., Discussion: The ChEAT psychometric characteristics are adequate. The questionnaire is valid. A cut-off point of 15 is recommended for adolescents., (Copyright © 2010 Wiley Periodicals, Inc.)