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Fire regimes in mountain landscapes of southern Europe have been shifting from their baselines due to rural abandonment and fire exclusion policies. Understanding the effects of fire on biodiversity is paramount to implement adequate management. Herein, we evaluated the relative role of burn severity and heterogeneity on bird abundance in an abandoned mountain range located in the biogeographic transition between the Eurosiberian and Mediterranean region (the Natural Park ‘Baixa Limia–Serra do Xurés’). We surveyed the bird community in 206 census plots distributed across the Natural Park, both inside and outside areas affected by wildfires over the last 11 years (from 2010 to 2020). We used satellite images of Sentinel 2 and Landsat missions to quantify the burn severity and heterogeneity of each fire within each surveyed plot. We also accounted for the past land use (forestry or agropastoral use) by using a land cover information for year 2010 derived from satellite image classification. We recorded 1,735 contacts from 28 bird species. Our models, fitted by using GLMs with Poisson error distribution (pseudo-R2-average of 0.22 ± 0.13), showed that up to 71% of the modelled species were linearly correlated with at least one attribute of the fire regime. The spatiotemporal variation in burnt area and severity were relevant factors for explaining the local abundance of our target species (39% of the species; Akaike weights > 0.75). We also found a quadratic effect of at least one fire regime attribute on bird abundance for 60% of the modeled species. The past land use, and its legacy after 10 years, was critical to understand the role of fire (Akaike weights > 0.75). Our findings confirm the importance of incorporating remotely sensed indicators of burn severity into the toolkit of decision makers to accurately anticipate the response of birds to fire management.

11 páginas, 5 tablas, 4 figuras, Reducing the toxicity caused by antibiotics on bacterial communities in the soil is one of the great challenges of this century. For this, the effectiveness of amending the soil with different bioadsorbents such as crushed mussel shell (CMS), pine bark (PB) and biomass ash (BA), as well as combinations of them (CMS + PB and PB + BA) was studied at different doses (0 g kg-1 to 48 g kg-1). Soil samples were spiked, separately, with increasing doses (0-2000 mg kg-1) of cefuroxime (CMX), amoxicillin (AMX), clarithromycin (CLA), azithromycin (AZI), ciprofloxacin (CIP) and trimethoprim (TMP). Their toxicity on bacterial growth was estimated using the tritium-labeled leucine (3H) incorporation method. Toxicity was observed to behave differently depending on the antibiotic family and bioadsorbent, although in different magnitude and at different doses. The toxicity of β-lactams (AMX and CXM) was reduced by up to 54% when the highest doses of bio-adsorbents were added due to the increase in pH (CMS and BA) and carbon (PB) contribution. Macrolides (CLA and AZI) showed slight toxicity in un-amended soil samples, which increased by up to 65% with the addition of the bio-adsorbents. The toxicity of CIP (a fluoroquinolone) increased with the dose of the bio-adsorbents, reaching up to 20% compared with the control. Finally, the toxicity of TMP (a diaminopyrimidine) slightly increased with the dose of bio-adsorbents. The by-products that increase soil pH are those that showed the highest increases of CLA, AZI, CIP and TMP toxicities. These results could help to prevent/reduce environmental pollution caused by different kinds of antibiotics, selecting the most appropriated bio-adsorbents and doses., This study has been funded by the Spanish Ministry of Science,Innovation and Universities through the projects RTI2018-099574-B-C21 and RTI2018-099574-B-C22 (FEDER Funds). David Fernández Calviño holds a Ramón y Cajal contract (RYC-2016-20411) financed by the Spanish Ministry of Economy, Industry and Competitiveness. Vanesa Santás Miguel holds a postdoctoral fellowship (ED481B-2022-081) financed by Xunta de Galicia. Laura Rodríguez González holds a predoctoral fellowship (ED481A-2021/309) financed by Xunta de Galicia. Funding for open access charge: Universidade de Vigo/CISUG.

Fire regimes in mountain landscapes of southern Europe have been shifting from their baselines due to the accumulation of fuel fostered by long-standing rural abandonment and fire exclusion policies. Understanding the role of fire on biodiversity is paramount to implement adequate management to mitigate the impacts of altered fire regimes and land abandonment on biodiversity. Here, we explored to what extent the spatiotemporal variation in burn severity has affected bird abundance of a mountain abandoned landscape located in the Atlantic-Mediterranean transition (NW Iberia). We took advantage of: (1) satellite images of Sentinel 2 and Landsat missions to compute burn severity indicators from 2010 to 2020, and (2) standardized bird surveys carried out over 206 point-counts along the breeding season of 2021. Bird abundance models were built from burn severity metrics together with well-known fire regime attributes (% of burnt area and time since fire). Our results showed that the spatiotemporal variation of burn severity significantly correlated with the abundance of the 39% of the modeled species, supporting the role of pyro-diversity in driving bird populations in our region. The burnt area also explained abundance patterns for 28% of species. Time since fire only correlated with the abundance of 3 species. Our findings confirm the importance of incorporating burn severity indicators into the toolkit of decision makers to anticipate the response of birds to fire management.

The presence of emerging pollutants, and specifically antibiotics, in agricultural soils has increased notably in recent decades, causing growing concern as regards potential environmental and health issues. With this in mind, the current study focuses on evaluating the toxicity exerted by three antibiotics (amoxicillin, trimethoprim, and ciprofloxacin) on the growth of soil bacterial communities, when these pollutants are present at different doses, and considered in the short, medium, and long terms (1, 8 and 42 days of incubation). Specifically, the research was carried out in 12 agricultural soils having different physicochemical characteristics and was performed by means of the leucine (H) incorporation method. In addition, changes in the structure of soil microbial communities at 8 and 42 days were studied in four of these soils, using the phospholipids of fatty acids method for this. The main results indicate that the most toxic antibiotic was amoxicillin, followed by trimethoprim and ciprofloxacin. The results also show that the toxicity of amoxicillin decreases with time, with values of Log IC ranging from 0.07 ± 0.05 to 3.43 ± 0.08 for day 1, from 0.95 ± 0.07 to 3.97 ± 0.15 for day 8, and from 2.05 ± 0.03 to 3.18 ± 0.04 for day 42, during the incubation period. Regarding trimethoprim, 3 different behaviors were observed: for some soils the growth of soil bacterial communities was not affected, for a second group of soils trimethoprim toxicity showed dose-response effects that remained persistent over time, and, finally, for a third group of soils the toxicity of trimethoprim increased over time, being greater for longer incubation times (42 days). As regards ciprofloxacin, this antibiotic did not show a toxicity effect on the growth of soil bacterial communities for any of the soils or incubation times studied. Furthermore, the principal component analysis performed with the phospholipids of fatty acids results demonstrated that the microbial community structure of these agricultural soils, which persisted after 42 days of incubation, depended mainly on soil characteristics and, to a lesser extent, on the dose and type of antibiotic (amoxicillin, trimethoprim or ciprofloxacin). In addition, it was found that, in this research, the application of the three antibiotics to soils usually favored the presence of fungi and Gram-positive bacteria., This study has been funded by the Spanish Ministry of Science, Innovation and Universities through the projects RTI2018-099574-B-C21 and RTI2018-099574-B-C22 (FEDER Funds). David Fernández Calviño holds a Ramón y Cajal contract (RYC-2016-20411) financed by the Spanish Ministry of Economy Industry and Competitiveness. Laura Rodríguez González hold a pre-doctoral fellowship (ED481A 2021/309) financed by Xunta de Galicia. Funding for open access charge: Universidade de Vigo/CISUG.

13 páginas, 4 figuras y 3 tablas, The widespread use of both heavy metals and antibiotics in livestock farming, followed by their subsequent arrival on agricultural soils through manure and slurry spreading, has become a problem of vital importance for human health and the environment. In the current research, a laboratory experiment was carried out for 42 d to study tolerance and co-tolerance of three tetracycline antibiotics (tetracycline, TC; oxytetracycline, OTC; chlortetracycline, CTC) in soils polluted with heavy metals (As, Cd, Zn, Cu, Ni, Cr, and Pb) at high concentrations (1000 mg kg-1 of each one, separately). Pollution induced community tolerance (PICT) of the bacterial community was estimated using the leucine incorporation technique. The log IC50 (logarithm of the concentration causing 50 % inhibition in bacterial community growth) values obtained in uncontaminated soil samples for all the heavy metals tested showed the following toxicity sequence: Cu > As > Cr ≥ Pb ≥ Cd > Zn > Ni. However, in polluted soil samples the toxicity sequence was Cu > Pb ≥ As ≥ Cd ≥ Cr ≥ Ni ≥ Zn. Moreover, at high heavy metal concentrations, the bacterial communities showed tolerance to the metal itself, this taking place in the long term for all the metals tested. The bacterial communities of the soil polluted with heavy metals showed also long-term co-tolerance to TC, OTC, and CTC. This kind of study, focusing on the eventual increases of tolerance and co-tolerance of bacterial communities in agricultural soil, favored by the presence of different kinds of pollutants, is of crucial importance, mostly bearing in mind that the appearance of antibiotic resistance genes in soil bacteria could be transmitted to human pathogens., This study has been funded by the Spanish Ministry of Economy and Competitiveness through the projects CGL2015-67333-C2-1-R and CGL2015-67333-C2-2-R (FEDER Funds). David Fernández-Calviño holds a Ramón y Cajal contract (RYC-2016-20411), financed by the Spanish Ministry of Economy, Industry and Competitiveness. Vanesa Santás-Miguel holds a pre-doctoral fellowship (ED481A-2020/089) financed by Xunta de Galicia.

The presence of antibiotics in soils may increase the selection pressure on soil bacterial communities and cause tolerance to these pollutants. The temporal evolution of bacterial community tolerance to different concentrations of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) was evaluated in two soils. The results showed an increase of soil bacterial community tolerance to TC, CTC and OTC only in samples polluted with the highest antibiotic concentrations tested (2000 mg kg−1). The magnitude of those increases was higher in the soil with the lower organic carbon content (1.6%) than in the soil with an organic carbon content reaching 3.4%. In the soil with low organic carbon content, the time-course evolution showed a maximum increase in the tolerance of bacterial communities to tetracycline antibiotics between 45 and 100 incubation days, while for longer incubation times (360 days) the tolerance decreased. In the soil with high organic carbon content, a similar behavior was found for OTC. However, for CTC and TC, slightly increases and decreases (respectively) were found in the bacterial community tolerance at intermediate incubation times, followed by values close to zero for TC after 360 days of incubation, while for CTC they remained higher than in the control. In conclusion, soil pollution due to tetracyclines may cause bacterial community tolerance to these antibiotics when present at high concentrations. In addition, the risk is higher in soils with low organic matter content, and it decreases with time., This study has been funded by the Spanish Ministry of Economy and Competitiveness through the projects CGL 2015-67333-C2-1-R and -2-R (FEDER Funds) and by Xunta de Galicia via BV1 research group (ED431C 2017/62-GRC). David Fernández Calviño holds a Ramón y Cajal contract (RYC-2016-20411) financed by the Spanish Ministry of Economy, Industry and Competitiveness. Vanesa Santás-Miguel and Laura Rodríguez González holds a pre-doctoral fellowship (ED481A-2020/089 and ED481A-2021/309, respectively) financed by Xunta de Galicia.

A laboratory experiment was performed to examine the medium-term influence of three tetracycline antibiotics (chlortetracycline, CTC; tetracycline, TC and oxytetracycline, OTC) at different concentrations in four agricultural soils with similar pH and different soil organic content. After a 42-days incubation period, three different soil enzymes ( -glucosidase, urease, and phosphomonoesterase) were estimated, as well as the phospholipid fatty acids (PLFAs). A residual effect was observed on all microbial parameters measured in the four soils affecting to the soil enzymes activity and soil microbial communities structure (PLFA pattern). A different microbial sensitivity to antibiotics was detected depending on both, soil type and the microbial property considered. Specifically, in general, no antibiotic effect or even a slight positive effect was observed for phosphomonoesterase and -glucosidase enzyme activities, respectively, while a negative effect was detected for urease activity values, particularly at higher doses of the antibiotics in a soil with a low organic matter content. The principal component analysis performed with the PLFAs data obtained for all soil samples showed different microbial communities depending mainly on soil type, followed by the antibiotic added to the soil (CTC, TC or OTC) and, in a lesser extent, by its concentration. In general, the PLFA patterns showed similar microbial communities structure due to OTC and TC addition in comparison to the microbial communities structure of soil treated with CTC. These results could be environmentally relevant, especially as regards potential effects of antibiotics on the soil microbiome and hence on health risk assessment of these antibiotics in soils., This study was funded by the Spanish Ministry of Economy and Competitiveness through the projects CGL2015-67333-C2-1-R and -2-R (FEDER Funds). The research group was also funded by Xunta de Galicia via the BV1 research group (ED431C 2017/62-GRC). David Fernández Calviño holds a Ramón y Cajal contract (RYC-2016-20411), financed by the Spanish Ministry of Economy, Industry, and Competitiveness. Vanesa Santás Miguel holds a predoctoral fellowship (ED481A-2020/089) financed by the Ministry of Education, University, and Professional Training of Xunta de Galicia.

The effect of fire severity and recurrence on the recovery of enzymatic activities (β-glucosidase, urease, acid phosphatase) and bacterial activity was monitored. Unburned and burned soil samples from soil affected by a high severity wildfire and by a low severity experimental fire were subjected in laboratory to a temperature gradient to simulate different fire severities. These samples were subjected to a second laboratory heat treatment to simulate the effect of recurrence. Soil temperature was measured and used to calculate the degree-hours reached by the soil. The results showed: a) a strong effect of repeated soil heating at different temperatures on soil microbial activity; b) a different sensitivity of enzymatic activities and bacterial activity to fire, c) the magnitude of changes in these biochemical properties was related to the extent of heat supplied to samples and the previous fire/heat history, and d) degree-hours are adequate to quantify the severity of heat treatments and to examine their effects on soil microbial activity. The relationships between degree-hours and the different biochemical properties analyzed clearly demonstrate that the usefulness of these biochemical properties to detect the soil microbial community response to the heat stress followed the order: urease activity > acid phosphatase activity >β-glucosidase activity ≫ bacterial activity., This study was supported by the Ministerio Español de Economía y Competitividad (AGL2012-39686-C02-01), the National Institute of Agricultural Research of Spain (INIA) through project RTA2017-00042- C05-02 cofunded by FEDER, and by Fundación MAPFRE. A. Barreiro and A. Lombao were recipients of FPU grants from the Ministerio Español de Educación (AP2010-2284, AP2010-1900).

To commemorate the 2015 International Year of Soil, the Spanish Society of Soil Science (SECS-Territorial Delegation of Galicia) and the University of Santiago de Compostela published the comic Living in the soil, with the aim of raising awareness amongst young people the importance of soil and the need to protect it. The initial version, Vivir no solo, published by the Galician Culture Council, was modified and adapted to the current specific scenarios of the countries where it was edited, and translated to Spanish, English and Italian as well as other languages (Galician, Catalan) for broadcasting it both at nationally at international level. In 2018 and 2019, the Spanish, Italian and Catalan versions were re-edited to commemorate the Decade International of Soils 2015-2024. All comic versions, including the English one, were edited in both paper (a total of 80.000 copies) and web format, the latter are available in the SECS web page (www.secs.com.es/publicaciones/).Since 2015 up to now, the comic has been successful used in many projects/activities carried out in various institutions (Educational Centers, Natural Parks, Museums, Nature Associations, soil-related Institutions). The soil is a hidden resource very little known to the public. It is under our feet, but we can´t see it because it is covered by vegetation. However, agricultural or forest soil is a living systems, it is the home to a huge diversity of organisms of different sizes that perform important ecological functions and others linked to human activities. The protagonists of the comic are a snail, an earthworm and a mole that inhabit the soil as well as a group of young people who, trying to solve a problem of soil use management that occurs in a little village, show us several important soil aspects (concept, components, functions, threats, degradation, protection and restoration). Events, etc). Some examples of these events are: Science City Project: Living in the soil, 2015, Spanish Research Council (CSIC), 2015; Would life on the planet be possible without the soil, SECS, CSIC, 2019; Vivere nel Suolo: Giornata di Legalitá Ambientale; Vivere nel Suolo and Giornata Mondiale del suolo, SECS, Italian Society of Soil Science, Parco dei Nebrodi, European Soil Science Conservation, 2018-2019. Considering the success of all these events, it seems that the comic “Living in the soil” has a great potential as an innovative and attractive publication of great interest to disseminate and raise awareness worldwide about the importance of this non-renewable resource for maintaining life on the planet. Acknowlegments. All persons and organizations that participate in this initiative of the edition (2015) and re-edition (2018, 2019) of the comic in the different languages.

The Spanish Society of Soil Science (www.secs.com.es, SECS) was founded in 1947 by the Spanish National Research Council (CSIC) with the main objective of promoting the study and knowledge of Soil Science. To achieve the slogan of 2015 International Year of Soils, Healthy soils for a healthy life, taking into account our long experience working with the concept of soil as a living system, we planned several projects and activities to promote the knowledge of this living and non-renewable natural resource among the different sectors of the society. Educational programs and cooperation agreements with different Educational Centers and the Administration as well as collaboration with Universities, Ecology and Nature Associations, National and International Parks, Museums and others Institutions related with the conservation of terrestrial ecosystems, were established in order to get them involved in the Educational Projects (organization, participation, financing). One critical point in the success of the projects was the elaboration of diverse, innovative educational materials to stimulate, in an attractive way, the knowledge of this non-renewable natural resource among different sectors of society as well as the level of implication of persons involved on the projects.In this contribution we will show some examples of these materials and initiatives concerning different aspects of Soil Science which result to be of interest to the general public: the comic Living in the Soil in different languages (Galician, Spanish, English, Italian and Catalan) and its corresponding Lesson Plans; Vivere nel Suolo: Giornata di Legalitá Ambientale;Vivire nel Suolo: Gionarta Mondiale del Suolo; Would life on the planet be possible without the soil?; Nature in the family; The game of soil; The elaboration of an Artificial Reproduction of a Soil Pedion and its inclusion in different centers related to soil; the creation of a Permanent Soil Room in the Museum of Natural History of Santiago de Compostela University (MHN); temporal exhibition Soil:Art Painting with soils; Pictures of José Caballo; group visits to the MHN and hence to the Permanent Soil Room; Soil Courses and Conferences; participation in Competitions. Our experience indicates that the inclusion of these innovative and attractive materials is very useful in the planning of activities related to soil to give visibility to this non-renewable resource hidden under the vegetation, the soil. We consider that these successful initiatives can be used as a prototype to transmit the message of importance on this natural resource, the soil, and the need of its protection all over the world.Acknowlegments. All persons and organizations that participate in all these SECS activities and projects.

The increase of bacterial community tolerance to Cu, and of cotolerance to the antibiotics tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC), was studied in three soils spiked with six different Cu concentrations (resulting in 0, 125, 250, 500, 750 and 1000 mg kg&minus, 1 into soils) in a laboratory experiment, after 42 days of incubation. The results show significant increases of bacterial community tolerance to the metal when soil Cu concentrations were between 125 and 500 mg kg&minus, 1. Moreover, Cu soil pollution also caused cotolerance to the three antibiotics studied but for higher Cu concentrations (1000 mg kg&minus, 1).

This work examines the results of a soil incubation experiment in the laboratory, under controlled conditions of humidity and temperature. The purpose was to determine the medium-term influence of the presence of antibiotics on the total and specific microbial biomass, determined by means of the phospholipid fatty acids (PLFAs) analysis (total microbial biomass, and specific fungal, bacterial, actinobacterial, Gram-negative bacterial and Gram-positive bacterial biomass), as well as the relationship between some of these groups (fungal biomass/bacterial biomass, Gram-negative-bacterial /Gram-positive bacterial). The experiment was performed with four different cultivated soils with a similar pH but different organic matter (OM) content, to which eight doses of three antibiotics of the tetracycline group (tetracycline, oxytetracycline and chlorotetracycline) were added. Microbial biomass measurements (total and specific groups) were performed after 42 days of incubation. As expected, the total and specific microbial biomass values were different in the four soils studied. Both the total and the specific microbial biomass showed a similar response to the presence of antibiotics, although in several cases the data were inconsistent and difficult to interpret. In general, in all soils the addition of chlorotetracycline and tetracycline slightly modified or increased, to a greater or lesser extent, the values of both total and specific microbial biomass, particularly at higher doses. However, in certain cases, biomass values decreased due to the addition of the highest dose of oxytetracycline. With regard to fungal/bacterial and Grambacteria/Gram bacterial biomass ratios, values slightly changed after the addition of the antibiotics. [ES] En este trabajo se examinan los resultados de una experiencia de incubación de suelos en el laboratorio, bajo condiciones controladas de humedad y temperatura, cuya finalidad fue determinar la influencia a medio plazo de la presencia de antibióticos en la biomasa microbiana total y específica, establecida a partir de los ácidos grasos de los fosfolípidos (biomasa microbiana total, biomasa fúngica, bacteriana, de actinobacterias, de bacterias Gramnegativas y de bacterias Gram-positivas) y de la relación entre algunos de estos grupos (hongos/bacterias, bacterias Gram-negativas/bacterias Gram-positivas). La experiencia se realizó con cuatro suelos de cultivo diferentes con un pH similar y con un diferente contenido de materia orgánica, a los que se aplicaron 8 dosis de tres antibióticos del grupo de las tetraciclinas (tetraciclina, oxitetraciclina y clorotetraciclina). Las medidas de biomasa microbiana (total y grupos específicos) se realizaron después de 42 días de incubación. Tal como era de esperar, los valores de la biomasa microbiana total y específica fueron diferentes en los cuatro suelos estudiados. Tanto la biomasa microbiana total como la específica mostraron una respuesta similar frente a la presencia de los antibióticos, aunque en varios casos los datos fueron inconsistentes y difíciles de interpretar. En general, en todos los suelos la adición de la clorotetraciclina y la tetraciclina modificó o incrementó en mayor o menor medida los valores tanto de la biomasa microbiana total e específica, particularmente a las dosis más altas. Sin embargo, en determinados casos, como consecuencia de la adición de la dosis más alta de oxitetraciclina, los valores de biomasa disminuyeron. En lo que respecta a las relaciones biomasa fúngica/bacteriana y biomasa bacterias Gram-positivas/bacterias Gram-negativas, los valores apenas variaron tras la adición de los antibióticos. [PT] Este artigo examina os resultados de uma experiência de incubação do solo em laboratório, sob condições controladas de humidade e temperatura. O objetivo foi determinar a influência, a médio prazo, da presença de antibióticos na biomassa microbiana total e em grupos específicos de microrganismos, a partir da análise de ácidos gordos fosfolipídicos (biomassa microbiana total, biomassa fúngica, biomassa bacteriana e de actinobactérias, e de biomassa de bactérias Gram-negativas e de bactérias Gram-positivas), assim como a relação entre alguns desses grupos (biomassa fúngica/biomassa bacteriana, bactérias Gram-negativas/bactérias Gram-positivas). A experiência foi realizada com quatro solos cultivados diferentes, com pH semelhante e com um conteúdo diferente de matéria orgânica, aos quais foram aplicadas oito doses de três antibióticos do grupo das tetraciclinas (tetraciclina, oxitetraciclina e clorotetraciclina). As determinações de biomassa microbiana (total e grupos específicos) foram realizadas após 42 dias de incubação. Como esperado, os valores da biomassa microbiana total e específica foram diferentes nos quatro solos estudados. Tanto a biomassa total como a específica mostraram uma resposta semelhante à presença de antibióticos, embora em vários casos os dados sejam inconsistentes e difíceis de interpretar. Em geral, em todos os solos, a adição de clorotetraciclina e tetraciclina modificou ou aumentou, em maior ou menor grau, os valores da biomassa microbiana total e específica, particularmente nas doses mais altas. Contudo, em certos casos, como resultado da adição de uma dose mais alta de oxitetraciclina, os valores de biomassa diminuíram. Em relação às razões biomassa fúngica/biomassa bacteriana e biomassa de bactérias Gram-negativas/biomassa de bactérias Gram-positivas, os valores variaram ligeiramente após a adição de antibiótico. Spanish Ministry of Economy and Competitiveness through the projects CGL2015-67333-C2-1-R and -2-R (FEDER Funds)

Wildfires are a major problem in Mediterranean forest ecosystems, affecting the same area year after year. Their severity is increasing, partly due to climate change and hence, every now and then, virulent fires of high severity spread ravage this region. The aim of this study was to evaluate the influence of fire regime (recurrence, severity) in soil microbial community structure analyzing the phospholipid fatty acid (PLFA) and the microbial functional diversity assessing the level physiological profiling technique (CLPP). Samples of a soil affected by a high severities wildfire and a soil affected by a low severity experimental fire were heated under laboratory conditions at different temperatures to simulate different fire severity. To simulate fire recurrence, the heating treatment was repeated after one month of incubation. The fire severity was estimated as the amount of heat supplied to samples by degree-hour methodology. A marked impact of fire regime on soil microorganisms was detected; the microbial community response varied depending on previous history of fire and the magnitude of changes in PLFA pattern and CLPP, was related to the amount of heat supplied to the samples. Wildfires had a greater impact on microbial community structure than subsequent soil heating in the laboratory. The total biomass and the biomass of specific groups of microorganisms decreased notably as a consequence of wildfire and minor changes were detected due to the experimental fire and soil heating under laboratory conditions. The results clearly showed the usefulness of PLFA pattern to study the effect of fire regimes and associated direct and indirect changes in soil microorganisms and in soil quality. The data also indicated that the degree-hour methodology rather than maximum temperature is adequate to simulate fire severity and evaluate the impact of thermal shock on soil ecosystems., This study was supported by the Ministerio Español de Economía y Competitividad (AGL2012-39686-C02-01), the National Institute of Agricultural Research of Spain (INIA) through project RTA2017-00042-C05-02, cofunded by FEDER and by Fundación Mapfre. A. Barreiro and A. Lombao were recipients of FPU grants from the Ministerio Español de Educación (AP2010-2284, AP2010-1900).

Toxicity on soil bacterial community growth caused by the antibiotics oxytetracycline (OTC) and chlortetracycline (CTC) was studied in 22 agricultural soils after 1, 8 and 42 incubation days. The leucine incorporation method was used with this aim, estimating the concentration of each antibiotic which caused an inhibition of 50% in bacterial community growth (log IC50). For OTC, the mean log IC50 was 2.70, 2.81, 2.84 for each of the three incubation times, while the values were 2.05, 2.22 and 2.47 for CTC, meaning that the magnitude of OTC toxicity was similar over time, whereas it decreased significantly for CTC with incubation time. In addition, results showed that the toxicity on bacterial community growth due to CTC is significantly higher than when due to OTC. Moreover, the toxicity on bacterial community growth due to both antibiotics is dependent on soil properties. Specifically, an increase in soil pH and silt content resulted in higher toxicity of both antibiotics, while increases in total organic carbon and clay contents caused decreases in OTC and CTC toxicities. The results also show that OTC toxicity can be well predicted by means of specific equations, using the values of pH measured in KCl and those of effective cation exchange capacity as input variables. CTC toxicity may be predicted (but with low precision) using pH measured in KCl and total organic carbon. These equations may help to predict the negative effects caused by OTC and CTC on soil bacteria using easily measurable soil parameters This study has been funded by the Spanish Ministry of Economy and Competitiveness through the projects CGL2015-67333-C2-1-R and -2-R (FEDER Funds), and by Xunta de Galicia via CITACA Strategic Partnership (ED431E 2018/07) and BV1 research group (ED431C 2017/62-GRC). David Fernández Calviño holds a Ramón y Cajal contract (RYC-2016-20411) financed by the Spanish Ministry of Economy, Industry and Competitiveness. Vanesa Santás Miguel holds a pre-doctoral fellowship founded by the University of Vigo SI

The toxicity exerted by the antibiotic sulfadiazine on the growth of soil bacterial communities was studied in two agricultural soils for a period of 100 days. In the short-term (2 days of incubation), the effect of sulfadiazine on bacterial growth was low (no inhibition or inhibition &lt, 32% for a dose of 2000 mg&middot, kg&minus, 1). However, sulfadiazine toxicity increased with time, achieving values of 40% inhibition, affecting bacterial growth in both soils after 100 days of incubation. These results, which were here observed for the first time for any antibiotic in soil samples, suggest that long-term experiments would be required for performing an adequate antibiotics risk assessment, as short-term experiments may underestimate toxicity effects.

Antibiotics discharged to the environment constitute a main concern for which different treatment alternatives are being studied, some of them based on antibiotics removal or inactivation using by-products with adsorbent capacity, or which can act as catalyst for photo-degradation. But a preliminary step is to determine the general characteristics and magnitude of the degradation process effectively acting on antibiotics. A specific case is that of sulfonamides (SAs), one of the antibiotic groups most widely used in veterinary medicine, and which are considered the most mobile antibiotics, causing that they are frequently detected in both surface- and ground-waters, facilitating their entry in the food chain and causing public health hazards. In this work we investigated abiotic and biotic degradation of three sulfonamides (sulfadiazine –SDZ-, sulfachloropyridazine –SCP-, and sulfamethazine –SMT-) in aqueous media. The results indicated that, in filtered milliQ water and under simulated sunlight, the degradation sequence was: SCP > SDZ ≈ SMT. Furthermore, the rate of degradation clearly increased with the raise of pH: at pH 4.0, half-lives were 1.2, 70.5 and 84.4 h for SCP, SDZ and SMT, respectively, while at pH 7.2 they were 2.3, 9.4 and 13.2 h for SCP, SMT and SDZ. The addition of a culture medium hardly caused any change in degradation rates as compared to experiments performed in milliQ water at the same pH value (7.2), suggesting that in this case sulfonamides degradation rate was not affected by the presence of some chemical elements and compounds, such as sodium, chloride and phosphate. However, the addition of bacterial suspensions extracted from a soil and from poultry manure increased the rate of degradation of these antibiotics. This increase in degradation cannot be attributed to biodegradation, since there was no degradation in the dark during the time of the experiment (72 h). This indicates that photo-degradation constitutes the main removal mechanism for SAs in aqueous media, a mechanism that in this case was favored by humic acids supplied with the extracts from soil and manure. The overall results could contribute to the understanding of the environmental fate of the three sulfonamides studied, aiding to program actions that could favor their inactivation, which is especially relevant since its dissemination can involve serious environmental and public health risks.

An extremely acid mine soil polluted with Cu was amended with pine bark, crushed mussel shell or a 1:1 mixture of these two by-products. The performance of the soil microbial community was measured as the bacterial and fungal community growth, which were monitored during 2 years following the amendments. Pine bark caused significant increases of microbial growth rates, but with distinct differences between fungal and bacterial groups. Bacterial growth increased transiently at intermediate rates of pine bark applications, but returned to control rates within 2 years of application. In contrast, pine bark applications consistently increased fungal growth with effects that were maintained throughout the study period. The addition of only crushed mussel shell to the mine soil caused very delayed positive effects on the bacterial growth and almost no significant effects on the fungal growth. However, the combination of pine bark with crushed mussel shells 1:1 mixtures caused positive growth responses of both bacteria and fungi that remained persistent throughout the 2 years of study. Fungal and bacterial growth were both suppressed in the mine soil by the lack of organic matter. In addition, bacterial growth was also secondarily suppressed by acidity, and hence, when organic matter (pine bark) additions were combined with pH increases (crushed mussel shell additions), bacterial growth was additionally stimulated. In conclusion, the proposed mixture of by-products (pine bark and crushed mussel shell) is suggested as a promising reclamation strategy for acid mine soils. These results also suggest that in soils like that studied here the organic matter limitation is a more important factor than the soil pH and Cu availability for fungal and bacterial performance.

The ecosystem response to fire is often linked to fire severityand recurrence, with potentially large consequences on bothaboveground and below–ground processes. Understandingthe fire impact has become increasingly important in the light ofrecent changes to disturbance regimes due to climate change.Although the impacts on the above vegetation and the belowsoil physical and chemical properties are well documented, itremains unclear how fire affects the fine-scale microorgan-isms. Microbial communities are responsible for drivingessential ecosystem processes and particularly sensitive tochanges induced in soil quality by wildfire or prescribed firedisturbances. This work is a review of the last three years’literature, dealing with the fire impact on mass, activity, anddiversity of soil microorganisms from soil A horizon.

The effects of adding two winery wastes, perlite waste (PW) and bentonite waste (BW), to an acid vineyard soil were assessed using some chemical and biological soil properties in a field study that lasted 18 months. The addition of PW (up to 81 Mg ha −1 ) had neither significant nor permanent effects on soil characteristics such as the pH, organic matter content or nutrient concentrations, the amounts of copper or zinc, or the electrical conductivity. Moreover, no persistent negative effects were found on the enzymatic activities after PW application. In contrast, soil that was amended with up to 71 Mg BW ha −1 showed increases in its soil pH values, exchangeable potassium and water soluble potassium and phosphorus contents. In addition, it caused significant increases in the electrical conductivity and water-soluble Cu. In addition, the phosphomonoesterase enzymatic activity decreased significantly (up to 28%) in response to the amendment with 71 Mg BW ha −1 . These results showed that adding BW and PW to the soil may be a good agronomic practice for recycling these types of wastes. However, in the case of PW, its use as a soil amendment must be performed with caution to control its possible harmful effects.

An excess of available nitrogen (N) in vineyard soil is considered detrimental for vine growth, making a thorough assessment of N mineralization dynamics in vineyard soils before the addition of winery waste necessary. This study assesses the changes in N mineralization in acid vineyard soils amended with bentonite winery waste (BW). Non-amended soil (control), BW and soil-waste mixtures (SBWM) with a low (+L) or high (+H) dose of BW were incubated for six weeks. After 7, 14, 21 and 42 days of incubation, the control soils, BW and SBWM were analysed for net ammonified N, net nitrified N and net mineralized N. Parameters related to the kinetics of N mineralization were also determined. The addition of BW increased the potentially mineralizable N (N0) in the amended soils (58–144% for the highest BW dose), although the mineralization rate was governed by the soil characteristics. Mineralizable N was only a small fraction (

Straw mulching is increasingly used after high severity wildfires for reducing post-fire runoff and erosion but can alter post-fire vegetation regeneration. However, information about the extent to which mulching affects the recovery of native vegetation is inconclusive. The soil seed bank plays an important role in the resilience of frequently disturbed shrubland communities but little is known about how it is affected by mulching treatments. In this study, we assessed the effects of straw mulching (2.0 Mg ha−1) on the recovery of vegetation after a wildfire in Galicia (NW Spain). For this purpose, we carried out a greenhouse and field-based study to evaluate the effects of mulching applied immediately after fire on the soil seed bank and recovery of vegetation cover in a shrubland area during the first year after wildfire. In the greenhouse, there were no differences in the total number of seedlings that emerged from the soil seed bank of mulched and untreated samples (634 seedlings m−2 vs 731 seedlings m−2). Species richness increased from 22 in untreated burned soils to 24 species in the mulched, burned soils. In the field, straw mulching favoured plant establishment and recovery of vegetation cover. At the end of the first post-fire year, plant cover was significantly higher (63%) in the mulching treatment compared to the untreated one (44%). Mulching did not affect species composition, and there was little evidence of the presence of non-native species. The results indicate that, in the present case, straw mulching immediately after the fire favoured recovery of plant cover in the first year after the fire by conserving the soil moisture.

Wildfire has become a major disturbance agent in Mediterranean area, with Galicia in the north-west of Spain having the most frequent fires. In order to combat soil erosion, different post-fire stabilization treatments can be applied, like adding different mulch materials. In a laboratory experiment we evaluated the effect of adding plant residues, commonly used in post-fire rehabilitation (wheat straw, coconut fibre, Eucalyptus bark and wood chips), at two different rates on the microbial response (respiration, bacterial and fungal growth, using leucine and acetate-in-ergosterol incorporation, and biomass and community structure by means of phospholipids fatty acid analysis) in an acid forest soil affected by a high intensity wildfire. We expected fungal growth to be favoured compared to bacterial growth after adding plant material with high C/N content, especially at the higher rate. Compared to unburnt soil, burnt soil had higher pH (increasing from 4.4 to 5.8) and more extractable (available) C, resulting in a relatively higher increase in bacterial compared to fungal growth. Adding Eucalyptus residues to burnt soil, especially wood chips, favoured fungal growth, especially at the higher rate. Straw addition favoured both fungal and bacterial growth and was the substrate most available for decomposition, as indicated by the higher soil respiration rates. Coconut fibre contained less available C. Adding Eucalyptus residue, at both rates, and coconut fibres at the high rate, initially inhibited bacterial growth, resulting in at most a 14 day lag period. Aiming at high fungal to bacterial growth in order to maximize stabilization of soils through fungi suggest Eucalyptus residues to the prime choice for further studies on effective mulching agents, although coconut fibres, with low degradation rates, may also be a suitable choice. Nevertheless, besides aspects related to soil quality, additional information concerning the efficiency of these materials to control post-fire soil erosion should also be considered before their implementation under field conditions.

Tetracycline antibiotics (TA) used in veterinary medicine reach terrestrial ecosystems mostly via the repeated applications of animal manures and slurries on agricultural soils, where they may cause toxic effects on bacterial communities. In the current work, we studied the efficacy of adding doses of 0, 6, 24 and 48 g kg of biomass ash (BA) to four different soils to reduce potential negative effects of tetracycline antibiotics. Specifically, soil samples were polluted with different concentrations of tetracycline, oxytetracycline or chlortetracycline, and the bacterial community growth was estimated using the H leucine incorporation technique. Soil amendment with BA increased soil pH (1.3–4.8 units), total carbon (0.7–5.8 g kg) and Fe and Al oxides concentrations (0.25–3.98 g kg), as well as bacterial activity (1–9 times compared to the control). In addition, BA amendment at high doses (24 or 48 g kg) resulted in a similar toxicity decrease for the three antibiotics, but with variations among soils. The reductions in antibiotics toxicity were very variable, ranging between 5% and 100% (total recovery). In view of that, the spreading of BA could be interesting as management practice to reduce risks of soil pollution and subsequent toxicity on bacterial communities due to tetracycline antibiotics., This study has been funded by the Spanish Ministry of Economy and Competitiveness through the projects CGL 2015-67333-C2-1-R and -2-R (FEDER Funds). David Fernández Calviño holds a Ramón y Cajal contract (RYC-2016-20411), financed by the Spanish Ministry of Economy, Industry and Competitiveness. Vanesa Santás Miguel holds a pre-doctoral fellowship founded by the University of Vigo.

The effect of tetracycline toxicity on the growth of soil bacterial communities was assessed using 22 agricultural soils with different pH values (between 4.1 and 7.4) and organic carbon concentrations (1.1–10.9%). Samples from all these soil types were spiked with different concentrations of tetracycline, and bacterial community growth was estimated after 1, 8, and 42 days of incubation, by using the H leucine incorporation method. Although tetracycline toxicity persisted in the soil during the incubation period, its magnitude gradually decreased with time. Moreover, tetracycline toxicity largely depends on soil characteristics, decreasing as a function of increasing organic matter, clay content, and effective exchangeable cation capacity (eCEC), and decreasing soil pH values. Further, an equation that allows the prediction of the direct effect of tetracycline on the growth of soil bacterial community was developed considering easily determinable parameters as the input; this equation will help achieve quick assessment of potentially hazardous situations., This study has been funded by the Spanish Ministry of Economy and Competitiveness through the projects CGL2015-67333-C2-1-R and -2-R (FEDER Funds). David Fernández Calviño holds a Ramón y Cajal con- tract (RYC-2016-20411), financed by the Spanish Ministry of Economy, Industry and Competitiveness.

The aim of this work was to study the effectiveness of two post-fire emergence rehabilitation techniques (seeding and mulching) for reducing soil erosion as well as their effects on the soil quality; therefore in the field, experimental plots of unburnt soil, burnt soil, burnt soil plus seeding and burnt soil plus mulching were established. Soil samples were collected from the A horizon and a wide range of physical, chemical and biological soil properties were analyzed to evaluate soil quality. The effect of fire on the vegetation cover was observed after one year and changes in soil properties persisted even after four years. The phospholipid fatty acids pattern showed that in the medium-term (8-48 months after the fire), the fire may modify the soil microbial communities by altering the plant community via plant-induced changes in the soil environment. No effect of seeding or mulching on the vegetation cover was observed. The mean efficiency in preventing soil erosion between 8 and 12 months after the fire and the application of the treatments was 11% for seeding and 65% for mulching. These stabilization treatments had a minor influence on the post-fire soil quality in the medium-term (48 months); therefore, taking into account its effectiveness for reducing soil erosion, the mulching treatment is recommended as the best post-fire stabilization technique.

Veterinary antibiotics reaching soils and water bodies are considered emerging pollutants deserving special attention. In this work, dissipation of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) is investigated. Dissipation experiments in filtered water, using simulated sunlight, resulted in the following degradation sequence: TC

In the present work, the effect of two by-products (pine bark and crushed mussel shell) on microbial biomass and community structure was studied in a soil from a mine tailing located in a copper mine. In a laboratory experiment, different doses (0, 12, 24, 48, 96 and 192 Mg ha-1) of pine bark, crushed mussel shell or mixtures of both by-products were added to the soil. The amended soil samples were incubated for one year at 60% of water holding capacity, and then 33 phospholipid fatty acids (PLFAs) were extracted from these samples and quantified. The PLFAs concentrations were used for different microbial biomass estimations: total biomass, bacterial biomass, fungal biomass, gram-positive (G+) biomass and gram-negative (G-) biomass. The addition of crushed mussel had no significant effects on the total soil microbial biomass, either bacterial of fungal biomass. However, the addition of pine bark increased the total microbial biomass in the soil (up to 40%), mainly due to increases in the fungal biomass (it increased 1600%). No synergistic effects were observed when the soil was amended with both, pine bark and crushed mussel shell. The main community structure changes were due to the addition of pine bark to the soil, and were also due to modifications in fungal communities. Our results suggest that the microbial biomass was mainly limited in the mine soil by low organic matter concentrations, and therefore, practices increasing the amount of soil organic matter should be priorities for soil reclamation. En el presente trabajo se estudió el efecto de dos subproductos (corteza de pino y concha de mejillón triturada) sobre la biomasa y estructura microbiana de un suelo procedente de una escombrera localizada en una mina de cobre. En un experimento realizado en laboratorio fueron añadidas al suelo diferentes dosis (0, 12, 24, 48, 96 and 192 Mg ha-1) de corteza de pino, concha de mejillón triturada y mezclas de ambos subproductos. Las muestras de suelo enmendado fueron incubadas durante un año al 60% de la capacidad de campo, y posteriormente 33 ácidos grasos de los fosfolípidos (PLFAs) fueron extraídos de estas muestras y cuantificados. La concentración de PLFAs fue utilizada para realizar distintas estimaciones de la biomasa microbiana: biomasa total, biomasa bacteriana, biomasa fúngica, biomasa de bacterias gram + y biomasa de bacterias gram -. La adición de concha de mejillón triturada no tuvo efectos significativos sobre la biomasa total ni sobre la biomasa bacteriana o fúngica. Sin embargo, la adición de corteza de pino al suelo incrementó la biomasa total del suelo (hasta un 40%), debido mayormente al incremento de la biomasa fúngica (se incrementó un 1600%). Tampoco se observaron efectos sinérgicos cuando el suelo fue enmendado con una mezcla de corteza de pino y concha de mejillón triturada. Los mayores cambios en la estructura de las comunidades microbianas fueron debidos a la adición de corteza de pino al suelo, y fueron además debidas a cambios en las comunidades fúngicas. Nuestros resultados sugieren que la biomasa microbiana del suelo de mina está mayormente limitada por la concentración de materia orgánica y, por tanto, deben ser priorizadas prácticas de manejo que contribuyan a incrementarla para la rehabilitación de este tipo de suelos. Neste trabalho foi estudado o efeito de dois subprodutos (casca de pinheiro e concha de mexilhão triturada) na biomassa e estrutura microbiana de um solo procedente de uma escombreira localizada numa mina de cobre. Numa experiência de laboratório, doses diferentes (0, 12, 24, 48, 96 e 192 Mg ha-1) de casca de pinheiro, concha de mexilhão triturada e misturas de ambos os subprodutos foram adicionados ao solo. Amostras de solo corrigido com os resíduos foram incubadas durante um ano a 60% da sua capacidade de retenção de água, e subsequentemente, 33 ácidos gordos dos fosfolípidos (PLFAs) foram extraídos a partir destas amostras e quantificados. A concentração de PLFAs foi usada para estimar vários tipos de biomassa microbiana: biomassa total, biomassa bacteriana, biomassa fúngica, biomassa de bactérias gram positivas e biomassa de bactérias gram negativas. A adição de concha de mexilhão triturada não teve nenhum efeito significativo na biomassa total ou na biomassa bacteriana ou fúngica. Porém, a adição de casca de pinheiro aumentou a biomassa microbiana do solo (até 40%), principalmente devido ao aumento da biomassa fúngica (a qual aumentou de 1600%). Não foi observado nenhum efeito de sinergismo quando o solo foi corrigido com uma mistura de casca de pinheiro e concha de mexilhão triturada. As maiores alterações na estrutura das comunidades microbianas foram produzidas pela adição de casca de pinheiro ao solo, as quais resultaram em alterações nas comunidades fúngicas. Os resultados sugerem que a biomassa microbiana do solo de mina é, maioritariamente limitada pela concentração de matéria orgânica. Assim, práticas que contribuam para o seu aumento devem ser prioritárias para a reabilitação deste tipo de solos. SI

The phospholipid fatty acid (PLFA pattern) and community level physiological profiling (CLPP) techniques were simultaneously used to evaluate the short- and medium-term effects produced by an experimental fire and two different stabilization treatments on the soil microbial communities. The study was performed in a scrubland ecosystem located in Galicia (N.W. of Spain). The measurements were made in soil samples collected from the top layer (0–5 cm) immediately and 90, 180 and 365 days after the fire and application of seeding and mulching treatments. Regardless of the technique used (PLFA, CLPP), the results indicated that the experimental fire caused marked changes in the soil microbial community, which persisted even 1 year after the fire, whereas the post-fire treatments induced no changes or slight changes on the microorganisms of this burned soil. In addition, a significant effect of the sampling time on the functional diversity and the soil microbial community structure, particularly on the latter, was observed. The relative importance of the two main factors (experimental fire and intra-annual variation) in determining the microbial community composition of the studied soils varied notably depending on the technique used; the experimental fire had a greater impact on the functional diversity (as evidenced by CLPP) than on the microbial community structure (as evidenced by PLFA). The results support the convenience of using both methodological approaches (PLFA pattern and CLPP) to gain more insight into the microbial communities of this degraded burned soil., This study was supported by Xunta de Galicia (08MRU002800PR) and Ministerio Español de Economía y Competitividad (AGL2008-02823 and AGL2012-39686-C02-01). A. Barreiro and A. Lombao are recipients of FPU grants from Spanish Ministry of Education.

We applied three different doses of crushed mussel shell (CMS) on two Cu-polluted acid soils to study the effect of these amendments on the growth of the bacterial community during 730 days. Soil pH increased in the short and medium term due to CMS addition. In a first stage, bacterial growth was lower in the CMS-amended than in the un-amended samples. Thereafter, bacterial growth increased slowly. The soil having the highest initial pH value (4.5) showed the first significant increase in bacterial growth 95 days after the CMS amendment. However, in the soil with the lowest initial pH value (3.8) bacterial growth increased significantly only after 730 days from the CMS addition. The highest dose of CMS caused that, at the end of the incubation period, pH value have increased 2 units, whereas bacterial growth was 4–10 times higher. In view of these results, CMS amendment could be considered as an agronomic sound practice for strongly acid soils (pH

Heavy metals far in excess of trace amounts that are required for healthy plant growth, cause harmful effects on soil microorganisms; however, studies concerning the characterization of microbial communities in mine soils are scarce. The present study is the first attempt to characterize, by means of the analysis of phospholipid fatty acid (PLFA) patterns, soil microbial community composition from a contaminated mine soil (Pb, As) subjected to different remediation technologies. A pot experiment was performed with a soil from the São Domingos mine (South of Portugal) with or without native herbaceous plants combined with the following soil treatments: control; inorganic fertilizer (NPK); inorganic fertilizer plus polyacrylate polymer; inorganic fertilizer plus organic amendment (compost); inorganic fertilizer plus both amendments (compost, polymer). The measurements of PLFA patterns were made on soil samples collected 5 months after the application of remediation treatments. The total microbial biomass and the biomass of specific groups increased notably after soil treatments, particularly those including organic amendments, and were significantly higher in presence of native plants than in the corresponding bare soils. The data also indicated that a plant cover rather than organic and inorganic treatments played the dominant role in determining the composition of the microbial community. An influence of different soil treatments on microbial composition was also observed; the effect of organic amendment being more pronounced than that of the remaining treatments. The results clearly showed the efficacy of a vegetation cover (native plants) combined with the use of organic amendment in the reclamation of this degraded mine soil.

Bentonite based organic-mineral wastes contains high concentrations of organic matter and plant nutrients and hence presents a high potential as a soil amendment. However, it also can have high salinity and high copper concentrations that may cause negative effects on microorganisms when the soil is amended with this type of wastes. In this work, the effect of soil amendment with a bentonite based winery waste on soil carbon mineralization was studied in acidic vineyard soils as an indicator of soil quality. The carbon mineralization in the waste is significantly lower and slower than that in the studied vineyard soils despite its significantly higher amount of organic carbon. However, when the bentonite winery waste was added to the soils, the carbon mineralization showed positive priming effects (increased between 78 and 337%). Therefore, reductions in the carbon mineralization, and hence changes on short-term organic matter turnover are not expected after bentonite waste amendment in acid soils.

Stable and labile soil organic compounds play different roles in the soil. It is a question of how far soil organic matter (SOM) fractions with different labilities vary as a function of climatic and management conditions. In order to answer this question stable (organic C -C-, total N -N-, organic P -Po-), and labile SOM fractions (total carbohydrates -CHt- and hot water soluble carbohydrates -CHw-) were measured monthly for two years in the 10-cm soil top-layer of an Entic Haplustoll, under conventional tillage (CT), vertical tillage (VT) and no-till (NT). Results showed that contents of all analyzed organic fractions were higher in NT than in VT and CT in almost all sampling dates. All organic compounds were less variable with time in NT and VT than in CT, in agreement with the smaller soil disturbance of NT and VT compared to CT. The more labile fractions varied as a function of short term changes in the climatic conditions, mainly temperature. Under soil disturbing tillage systems, the most stable fractions tended to decrease and the more labile to increase with time. This was attributed to the transformation of the more stable into the more labile fractions, possibly due to the disruption of aggregates produced by tillage that favored SOM mineralization. Po was the less variable compound, even under the most disturbing tillage conditions. The quotients C/N, CHt/C and CHw/C evolved similarly in all tillage systems, indicating that that tillage systems change the amount but not the quality of SOM.

The enormous quantity of plant waste produced from greenhouse tomato crops is an environmental problem that should be solved by recycling that waste into valuable organic products through low-cost technologies, such as vermicomposting. Feasibility of vermicomposting greenhouse tomato-plant waste (P) using paper-mill sludge (S) as complementary waste was investigated by this study. Earthworm development in P, S, and two mixtures of both wastes was monitored over 24 weeks and compared with that in cow dung (D), an optimum organic-waste to be vermicomposted. The effectiveness of vermicomposting to biostabilize those wastes was assessed by analysing phospholipid fatty acid composition, chemical features, plant-nutrient content, metal concentration, enzyme activities, and germination index (GI). A commercial vermicompost was also analyzed and taken as a reference of vermicompost quality. Earthworms did not survive in P alone, but a mixture of P with S at a ratio of 2:1 or 1:1 resulted in earthworm development similar to that observed in D. Phospholipid fatty acid analysis revealed that earthworm activity strongly transformed initial microbiota inhabiting the wastes, giving rise to vermicompost microbial communities which were similar to that of a commercial vermicompost. Both mixtures of P and S were properly biostabilized through vermicomposting, as indicated by decreases in their C:N ratio and enzyme activities together with increases in their degree of maturity (GI ~ 100 %) after the process. This study demonstrates that the vermicomposting of tomato-plant waste together with paper-mill sludge allows the recycling of both wastes, thereby improving the environmental sustainability of greenhouse crops.

The aim of this study was to assess the influence of pH on copper mobilization in two copper-rich acid soils (from vineyard and mine) amended with crushed mussel shell. Crushed mussel shell amended soils (0–48 Mg ha−1) were subjected to the effect of several acid and alkali solutions in a batch experiment in order to study their copper release. Copper distribution was studied in decanted soils from batch experiments using a sequential extraction procedure, whereas the effect of crushed mussel shell on copper release kinetics was studied using a stirred flow reactor. When soils were treated with acid solutions, the copper mobilization from non-amended soils was significantly higher than from the amended samples. Major changes in copper fractionation were an increase of the acid soluble fraction in acid-treated vineyard soil samples with shell dose. For the mine soil, the oxidable fraction showed a relevant diminution in acid-treated samples at the highest crushed mussel shell dose. For both soils, copper desorption rates diminished up to 86 % at pH 3 when crushed mussel shell was added. At pH 5, copper release rate was very slow for both soils decreasing up to 98 % for the mine soil amended with the highest shell dose, whereas no differences were observed at pH 7 between amended and non-amended soils. Thus, crushed mussel shell addition could contribute to reduce potential hazard of copper-enriched soils under acidification events.

Wildfires are a global problem that can require the application of fire-fighting chemicals for combating them. These compounds can have negative effects on forest ecosystems; however, there are few studies about their influence on the soil microbial community. The aim of this work is to analyse under field conditions the impact of a prescribed fire and the addition at normal field doses of three different fire-fighting chemicals (foaming agent, ammonium polyphosphate, Firesorb) on different soil properties, 10 years after the fire and retardant addition. The study was performed in a Humic Cambisol under scrubland located in Galicia (NW Spain). Several physical, physicochemical, chemical (water holding capacity, pH, electric conductivity, total C and N, hydro-soluble C and carbohydrates), biochemical and microbiological [biomass C, enzyme activities, respiration, bacterial growth, fungal biomass and growth, biomass and community composition by the phospholipid fatty acid (PLFA) pattern] properties were analysed in the 0–2- and 2–5-cm soil layers. A marked effect of soil depth and no effects of prescribed fire on most analysed properties were observed, suggesting that soil chemical quality was recovered after 10 years, although changes in microbial community composition were still detected 10 years after the prescribed fire and the retardant addition. The PLFA pattern combined with principal component analysis allows us to differentiate the microbial communities according to both soil depth and soil treatment. The ammonium polyphosphate was the fire-fighting chemical with the strongest effects on the composition of soil microbial communities, which is in accordance with marked changes observed in vegetation., This research was supported by the Spanish Ministry of Education and Science through the projects AGL2001-1242-CO4-01 and AGL2008-02823. A. Barreiro is a recipient of an FPU grant from the Spanish Ministry of Education (AP2010-2284). Part of this work has been funded with a PFU program grant awarded to A. Barreiro (short stays).

The implementation of post-fire stabilisation techniques in forests ecosystems located in the NW of Spain is required since high severity wildfires are common and the risk of erosion is high due to pronounced terrain relief in combination with abundant precipitation; however, there is limited quantitative information on the relative effectiveness of these techniques. The effectiveness of two stabilisation techniques, seeding and mulching, in reducing soil erosion was evaluated as well as their effects on soil quality. The study was performed on a hillslope area located in Laza (NW of Spain) affected by a high severity wildfire in September 2010. Four treatments were established: unburnt control soil, burnt control soil, burnt soil with rye seeding and burnt soil with straw mulch. For the different soil treatments, the sediments production as well as different physical, chemical and microbiological soil properties were measured over a four month period. The results showed that initially the wildfire induced important changes in most properties analyzed and that these effects persisted after 4 months. The data also indicated that both stabilisation treatments had no effects on the soil properties analyzed but reduced significantly the sediments yield compared to that of the control burnt soil. The mean efficiency of seeding and mulching treatments in preventing soil erosion was 34–42% and 73–94%, respectively, showing that, in the short-term (4 months), mulching was the most effective treatment for reducing post-fire erosion., This study was supported by the Consellería de Medio Rural de la Xunta de Galicia (08MRU002400PR) and by the Ministerio de Ciencia e Innovación (AGL2008-02823), Spain.

Because of the use of agricultural land for wine production and the frequent use of copper (Cu)-based fungicides, Cu concentration has been increasing in soils in many parts of the world. In vineyards with acid parent materials, low soil pH may also encourage Cu toxicity, but it is common to use lime in order to increase the soil pH and improve crop yields. Thus, vineyard soils may have large variations in pH, which will affect the microbial communities, making it difficult to isolate possible toxic effects of Cu on soil microbes. Here, analyses of phospholipid fatty acid (PLFA) patterns and pollution-induced community tolerance (PICT, using leucine incorporation) were used to study the effect of Cu accumulation at small to medium concentrations in acid soils (pH 4.05.8) in vineyards with different land-use history (young, old and abandoned vineyards). The results suggested that soil pH played a dominant role in determining the composition of the microbial community of the soils. Only a small effect of soil Cu could be detected and the effect on microbial community composition was much less than the pH effect. PICT analysis suggested that bacterial communities in old vineyards were more tolerant of Cu than those in the abandoned vineyards. However, increased PICT (Cu tolerance of the bacterial community) was not directly correlated with Cu concentration in the soils. Instead, the estimated Cu tolerance was significantly correlated with soil pH. (Less)

Pollution induced community tolerance (PICT) has been suggested as an end-point measurement less affected by confounding environmental factors compared to standard methods of microbial growth, activity and community composition. We evaluated the use of PICT to determine Cu toxicity in vineyard soils polluted with Cu based fungicides (25-1120 mg Cu kg(-1)). These soils also varied in pH (4.3-7.3), organic C (0.31-6.91%) and texture (14-56% silt). PICT was estimated as bacterial community tolerance to Cu measured by the [H-3]leucine incorporation method. Bacterial tolerance to Cu increased 9 times in the most polluted compared to the unpolluted soils. Cu tolerance was also affected to a minor degree by pH, organic C and soil texture. Lower bacterial tolerance was found in soils with high pH and organic C, probably due to Cu becoming less bioavailable in soils with high pH and organic C content. The silt content appeared to increase bacterial tolerance, probably due to fine soil particles decreasing Cu bioavailability during the PICT detection phase. Despite the effects of other environmental factors, the main determinant of increased bacterial community tolerance to Cu was the pollution level. PICT measured with the leucine incorporation technique thus appears to be a sensitive and stable concept to evaluate toxic impacts, unless soils with very different pH, organic C or texture are studied. (C) 2011 Elsevier Ltd. All rights reserved.

Atrazine is one of the most used herbicides worldwide; however, consequences of its long-term agricultural use are still unknown. A laboratory study was performed to examine changes in microbial properties following ethylamino-15N-atrazine addition, at recommended agronomic dose, to five acidic soils from Galicia (NW Spain) showing different physico-chemical characteristics, as well as atrazine application history. Net N mineralization was observed in all soils, with nitrate being the predominant substance formed. The highest values were detected in soils with low atrazine application history. From 2% to 23% of the atrazine-15N was found in the soil inorganic-N pool, the highest values being detected after 9 weeks in soils with longer atrazine application history and lower indigenous soil N mineralization. The application of atrazine slightly reduced the amount of soil N mineralized and microbial biomass at short term. Soluble carbohydrates and β-glucosidase and urease activity decreased with incubation time, but were not significantly affected by the single application of atrazine. Microbial community structure changed as consequence of both soil type and incubation time, but no changes in the phospholipid fatty acid (PLFA) pattern were detected due to recent atrazine addition at normal doses. The saturated 17- to 20-carbon fatty acids had higher relative abundance in soils with a longer atrazine history and fungal biomass, as indicated by the PLFA 18:2ω6,9, decreased with the incubation time. The results suggested that the PLFA pattern and soil N dynamics can detect the long-term impact of repeated atrazine application to agricultural soils.