GEAGrupo de Edafología Ambiental - Environmental Soil Science Group
Department of Agrochemistry and Environment University Miguel Hernández Edificio Alcudia, Avda de la Universidad s/n. 03202 Elche Alicante Spain
agro.ambiente@umh.es
Multidisciplinary group working in Soil Science (backgrounds of Geology, Biology, Chemistry, Environmental Science) . Colaborations with Geographers, Statisticians.
Research lines:
* Soil quality * Soil polution * Soil degradation and remediation * Fire effects on soils * Use of wastes in soils * Land management * GIS and Remote sensing applied to soil studies * Use of Near Infrared Spectroscopy (NIR) to soil and organic wastes studies * Soil water repellency * Hidrogeology in semiarid areas * Applied mineralogy and environmental geochemistry
The most relevant publications in scientific journals are listed below:
Abstract: Water shortage and soil degradation are the two most important environmental problems in the Mediterranean area. For this reason, strategies for soil and water conservation are necessary. Our objective was to evaluate the use of treated wastewater as an irrigation source to help alleviate these problems. Short-term effects on several soil fertility properties were evaluated in an agricultural area located at Biar (Alicante, SE Spain), where grapes (Vitis labrusca) are grown. Three treatments: fresh water (control), and treated wastewaters from secondary and tertiary treatment were evaluated for 2 years. We found a slight increase in soil organic carbon content in plots irrigated with the secondary treatment. These plots also had increased electrical conductivity (EC) and increased available Na content due to the high values of EC in wastewater. Laboratory analyses also show a decrease in aggregate stability for all treatments, presumably due to the wetting and drying (WD) cycles associated with each irrigation dose. These WD cycles may also explain changes in microbial biomass carbon and basal soil respiration. We recommend modifying the dose of irrigation in order to reduce the quantity applied and to increase the frequency of application to avoid the loss of aggregation. We also suggest long-term studies to assess the feasibility of wastewater reuse.
Abstract: Immediately following a wildfire, a layer of ash and charred material typically covers the ground. This layer will gradually be reduced, being redistributed by rainfall, wind or animals, by partial dissolution and by incorporation into the soil. Ash can increase or decrease the post-fire runoff and erosion response, depending upon the soil and ash properties and the ash thickness. One aspect of ash that has remained unknown and which may affect the variability in the hydrological response of the burned soil is its wettability. This study examines the wettability of ash using the Water Drop Penetration Time (WDPT) test, its relationship with total organic carbon (TOC) content and colour, and its effects when incorporated into the soil. Ash samples (n = 48) were taken from five wildfires in the Mediterranean basin encompassing a range of burn severities. Additional ash material was generated from exposing plant leaves (Rosmarinus officinalis, Pinus halepensis and Quercus coccifera) to specific temperatures in a muffle furnace (200-700 °C). Selected laboratory ash types were also mixed with wettable and water repellent soil material to assess their effect on soil wettability. Over 30% of ash samples from the wildfire sites exhibited water repellency (WR), with WDPT levels ranging from low to extreme. This variability appears to be related to differences in fire severity, combustion completeness of the biomass, vegetation type and subsequent rainfall events. The laboratory-generated ash exhibited a greater frequency and persistence of water repellency at lower furnace temperatures (200-300 °C), with ash from R. officinalis being generally less water repellent than that derived from the other two species. The water repellency levels of ash correlated well with TOC (r = 0.80), whereas neither of these parameters correlated very well with ash colour (r = 0.57 for TOC and r = 0.59 for WR). This suggests that ash colour, which is widely used as a parameter in classifying burn severity in the field, may not necessarily be a very accurate indicator. Adding water repellent ash to wettable soil induced WR, whereas the addition of wettable ash to water repellent soil had the opposite effect. A wetting-drying cycle can reduce the water repellency of a soil-ash mixture. There were substantial differences between wildfire- and laboratory-generated ash in terms of organic carbon content and colour, suggesting that the combustion conditions in a furnace may not adequately represent those in wildfires. In contrast to what is generally assumed, our findings demonstrate that ash from vegetation fires can be water repellent. This is likely to have implications for runoff responses and nutrient fluxes not only when ash is present on the ground surface, but also following its redistribution and incorporation into the soil.
Abstract: Wildfire is the major disturbance in Mediterranean forests. Prescribed fire can be an alternative to reduce the amount of fuel and hence decrease the wildfire risk. However the effects of prescribed fire must be studied, especially on ash properties, because ash is an important nutrient source for ecosystem recovery. The aim of this study is to determine the effects of a low severity prescribed fire on water-soluble elements in ash including pH, electrical conductivity (EC), calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), aluminum (Al), manganese (Mn), iron (Fe), zinc (Zn), silica (SiO2) and total sulphur (TS). A prescribed fire was conducted in a cork oak (Quercus suber) (Q.S) forest located in the northeast part of the Iberian Peninsula. Samples were collected from a flat plot of 40Ã70 m mainly composed of Q.S and Quercus robur (Q.R) trees. In order to understand the effects of the prescribed fire on the soluble elements in ash, we conducted our data analysis on three data groups: all samples, only Q.S samples and only Q.R samples. All three sample groups exhibited a significant increase in pH, EC (p<0.001), water-soluble Ca, Mg, Na, SiO2 and TS and a decrease in water-soluble Mn, Fe and Zn. Differences were identified between oak species for water-soluble K, Al and Fe. In Q.S samples we registered a significant increase in the first two elements p<0.001 and p<0.01, respectively, and a non-significant impact in the third, at p<0.05. In Q.R data we identified a non-significant impact on water-soluble K and Al and a significant decrease in water-soluble Fe (p<0.05). These differences are probably due to vegetation characteristics and burn severity. The fire induced a higher variability in the ash soluble elements, especially in Q.S samples, that at some points burned with higher severity. The increase of pH, EC, Ca, Mg, Na and K will improve soil fertility, mainly in the study area where soils are acidic. The application of this low severity prescribed fire will improve soil nutrient status without causing soil degradation and thus is considered to be a good management strategy.
Abstract: This contribution is focused on the study of the mineralogical changes occurring in the ceramic body after heating ceramic clays. Chile has an important local ceramic industry. Five deposits of clays with industrial applications were studied. The clays came from San Vicente de Tagua-Tagua (SVTT), Litueche (L), Las CompañÃas-RÃo Elqui (LC), La Herradura-Coquimbo (LH) and Monte Patria-Coquimbo (MP). The samples were heated to 830, 975, 1080 and 1160 °C keeping at the maximum temperature for 35 min. The bending strength of each ceramic body was determined at 1100 °C. Mineralogical analysis of the fired samples was carried out by X-ray diffraction. The SVTT contained quartz, spinel, cristobalite, microcline, albite, anorthite, hematite and enstatite; the LC clays quartz, mullite, spinel, microcline, albite, anorthite, hematite, diopside, enstatite, illite/muscovite and talc; the LH clays quartz, cristobalite, microcline, albite, anorthite, hematite, diopside, illite and augite; the MP clays quartz, cristobalite, microcline, albite, anorthite, hematite, diopside, gehlenite, enstatite and wollastonite and the L clays quartz, microcline and mullite. The persistence of illite at at least 900 °C was observed for LC and LH. SVTT and LH showed the required specifications for earthenware. The L clays were refractory clays with very low bending strength.
Abstract: Fire can affect soil properties depending on a number of factors including fire severity and soil type. Aggregate stability (AS) refers to soil structure resilience in response to external mechanical forces. Many authors consider soil aggregation to be a parameter reflecting soil health, as it depends on chemical, physical and biological factors. The response of AS to forest fires is complex, since it depends on how fire has affected other related properties such as organic matter content, soil microbiology, water repellency and soil mineralogy. Opinions differ concerning the effect of fire on AS. Some authors have observed a decrease in AS in soils affected by intense wildfire or severe laboratory heating. However, others have reported increases. We provide an up to date review of the research on this topic and an analysis of the causes for the different effects observed. The implications for soil system functioning and for the hydrology of the affected areas are also discussed. Generally, low severity fires do not produce notable changes in AS, although in some cases an increase has been observed and attributed to increased water repellency. In contrast, high severity fires can induce important changes in this property, but with different effects depending on the type of soil affected. The patterns observed can vary from a disaggregation as a consequence of the organic matter destruction, to a strong aggregation if a recrystallization of some minerals such as Fe and Al oxyhydroxides occurs when they are present in sufficient quantities in the soil, after exposure to high temperatures. Because of the complexity of the different possible effects and reasons for the potential changes in the fire-affected soil aggregates, the inclusion of other parameters in the studies is necessary to understand the results. The suggested parameters to include in the examination of AS are: soil organic matter, microbial biomass, water repellency, texture, aggregate size distribution, together with accurate ways of estimating fire severity. More research is needed on what implications there are for soil system functioning with the changes suffered by aggregates after fire. Studies including measurements at very different scales: from AS measurements in the laboratory to erosion rates measured at pedon, slope and catchment scales are also necessary.
Abstract: The effects of different fire intensities on physiochemical soil properties have been studied in this research. The experiment was conducted in a eucalyptus forested area near the Namadgi National Park (ACT, Australia), and four fire intensities were achieved by adding different amounts of fuel load: 0 xa0;kg xa0;mâ xa0;2 (control), 2 xa0;kg xa0;mâ xa0;2 (low fire intensity), 4 xa0;kg xa0;mâ xa0;2 (moderate fire intensity) and 8 xa0;kg xa0;mâ xa0;2 (high fire intensity). Soil surface peak temperatures reached at each plot were 14, 142, 317 and 525 xa0;°C, respectively. Immediate changes in soil properties under different fuel loads were studied and monitored monthly during a 7-month period. Average pH increased significantly with fuel load immediately after fire and decreased progressively to initial values. Changes in soil pH from burnt plots seem to be caused mainly by an ephemeral ash layer, and the recovery time has been relatively short. The complete oxidation of soil organic matter and the release of substantial amounts of cations after high fire intensity also contributed to increased pH. Only small variations in soil texture have been observed in this study even after high intensity fire, although the clay content decreased slightly during the experiment. This can be due to relatively low pre-burn clay content, but also to spatial variability of texture. In this case, post-fire erosion processes might have contributed to decreased clay content and are probably more important than other processes associated to temperature. Aggregate stability indices showed good correlation coefficients with the organic matter content. The role of organic matter as cementing agent of soil aggregates is extremely important after fire, since aggregate stability indices showed good correlation coefficients with the organic matter content. Low intensity fire enhanced soil water repellency. In this case, fire-enhanced soil water repellency persisted or increased progressively, but decreased below initial levels at the end of the experiment, but soil water repellency was completely destroyed after moderate or high fuel load treatments. The persistence of wettable conditions after destruction of soil water repellency can be considered as an index of fire severity, since it is a direct consequence of strong reduction of organic matter content.
Abstract: Previous studies have shown that long-term irrigation with wastewater can lead to the development of soil water repellency. Little is known about the longevity of this effect. Here we address this research gap by examining the effect of long-term (~Â 20Â years) use of low-quality wastewater for disposal purposes, followed by 6Â years of [`]recovery' with no irrigation, on the wettability of calcareous sandy soil (Xerofluvent) under a Populus alba tree stand used as a "green filter" in SE Spain. Water repellency (WR) and soil organic matter content (SOM) were determined for 120 air-dry samples from the plot and 80 control samples from adjacent and otherwise similar non-irrigated areas. To account for plot micro-topography 40 samples each were taken from ridges (R; 0-5Â cm depth), furrows (F; 0-5Â cm), and furrows at depth (FD; 5-10Â cm). The controls included 40 samples each (0-5Â cm depth) from unvegetated and unploughed soil, and from soil under the P. alba plantation. All control samples were non-repellent whereas at the irrigated plot, water repellency was present for 48, 95 and 93% of ridge, furrow and furrow-depth samples respectively. WR and SOM was strongly correlated within the whole sample population (R2Â =Â 0.623**) and within two sample groups (R: R2Â =Â 0.783**; FD: R2Â =Â 0.424**), but weakly within F samples (R2Â =Â 0.072 n.s.). The latter showed the highest frequency and persistence (WDPT) of WR, indicating that not only quantity of SOM is controlling WR. Exploratory kaolinite clay additions (0.5-8%) to samples substantially reduced WR even at the lowest concentration, indicating that this could be a promising amelioration treatment for the WR in the soils investigated here. We conclude that for the conditions studied here (i) long-term use with poor-quality wastewater for disposal had led to the development of soil WR, (ii) a 6-year period of [`]recovery' (i.e. non-irrigation) was insufficient to eliminate the induced WR, and (iii) kaolinite addition could be a promising amelioration treatment for these sandy soils.
Abstract: A field study was conducted in order to study the effects of different wildfire severities on [1] soil organic matter content, [2] soil water repellency, and [3] aggregate stability; [4] the distribution of soil water repellency in aggregate sieve fractions (1-2, 0.5-1, 0.25-0.5 and < 0.25 mm) was also studied. Five similar burned sites and two long-unburned control sites were selected under mixed fir and pine forests in volcanic highlands from Michoacán, Mexico. Soil water repellency was observed in soil samples from all sites, although changes were influenced by fire severity. Sites affected by low severity fires did not show important changes in burned soils in comparison with controls, while high severity fires caused different responses: water repellency was increased or destroyed probably due to temperatures below or above 200-250 °C during burning. The degree of wettability/repellency from the fine earth fraction of burned soils seems to be conditioned by < 0.5 mm aggregates, more than coarser aggregates which always showed a higher degree of wettability. It is suggested that destruction of organic matter during burning occurs principally in coarse aggregates, where combustion can be more intense. Aggregate stability (measured using pre-wetted aggregates between 4 and 4.8 mm) did not change under low severity burning but it was considerably reduced in the case of a high fire severity. Losses of organic matter and destruction of water repellency seem to be the reasons for that reduction in this type of soil in contrast to previous studies, where aggregate stability increased after burning. Changes in both properties (water repellency and aggregate stability) are expected to induce modifications in runoff and soil loss rates at the hillslope scale.
Abstract: The capacity of different microbial groups to recolonise soil after a fire event will be decisive in determining the microbial community after the fire. Microbial recovery after a wildfire that occurred in Sierra la Grana (Alicante province, southeast Spain) was tracked for 32Â months after the fire. Colony forming units (CFUs) of different microbial groups, microbial biomass, soil respiration, bacterial growth (leucine incorporation) and changes in the microbial community structure (phospholipid fatty acid (PLFA) analysis) were determined directly after the fire and four times during the recovery period. Direct effects were reflected by low values of most microbiological variables measured immediately after the fire. Microbial biomass increased during the first year after the fire but was below the unburned reference site 32Â months after the fire. Bacterial activity and soil respiration showed the highest values immediately after the fire, but decreased to values similar to that of the unburned reference site or even lower (respiration) 32Â months after the fire. Colony forming units of bacterial groups estimated by the plate count method peaked 8Â months after the fire, but then decreased, showing values similar to the unburned reference site at the end of the study, with the exception of spore formers, which were 20 times higher than the reference site 32Â months after the fire. Fungal CFUs were more sensitive to the fire and recovered more slowly than bacteria. Fungi recovering less rapidly than bacteria were also indicated by the PLFA pattern, with PLFAs indicative of fungi being less common after the fire. The recovery of microbial biomass and activity was mirrored by the initially very high levels of dissolved organic carbon being consumed and decreasing within 8Â months after the fire. The wildfire event had thus resulted in a decrease in microbial biomass, with a more bacteria-dominated microbial community.
Abstract: The problem of estimating and predicting spatial distribution of a spatial stochastic process, observed at irregular locations in space, is considered in this paper. Environmental variables usually show spatial dependencies among observations, with lead one to use geostatistical methods to model the spatial distributions of those observations. This is particularly important in the study of soil properties and their spatial variability. In this study geostatistical techniques were used to describe the spatial dependence and to quantify the scale and intensity of spatial variations of soil properties, which provide the essential spatial information for local estimation. In this contribution, we propose a spatial Gaussian linear mixed model that involves (a) a non-parametric term for accounting deterministic trend due to exogenous variables and (b) a parametric component for defining the purely spatial random variation due possibly to latent spatial processes. We focus here on the analysis of the relationship between soil electrical conductivity and Na content to identify spatial variations of soil salinity. This analysis can be useful for agricultural and environmental land management.
Abstract: The atmospheric levels of carbon dioxide (CO2) and other greenhouse gases (GHGs) have increased dramatically since the industrial revolution. The atmospheric enrichment with CO2 and other GHGs has resulted in multiple negative consequences: such as the increase in the average temperature and the rise of the sea level. Hence, there is a growing interest in developing feasible methods to reduce the atmospheric levels of these gases. One of these strategies is to enhance C sequestration through the increase of soil organic carbon (SOC) pool by the amendment of agricultural soils with sewage sludge. However, there is considerable uncertainty about the effects (positive or negative) of sewage sludge applications on the SOC pool. Thus, a simple approach developed under laboratory conditions is presented to discern the effect of a single sewage sludge application of 50 t haâ1 on the short-term SOC pool in 60 contrasting agricultural soils. The role of soil factors in the C sequestration of the recently added carbon was also studied. The application of sewage sludge supposed a mean increase of 1.7 ± 1.6 g SOC kgâ1, with peak increases of up to 3.8 g SOC kgâ1 and decreases of up to 4.6 g SOC kgâ1. The initial SOC contents conditioned the C sequestration after sewage sludge application, and no other soil property was related.
Abstract: Fire causes changes in soil moisture content (MC) and also in other soil properties depending on the maximum temperature reached. However, after fire, MC is partially rapidly restored due to re-equilibrium with air moisture or following rainfall, which in turn affects the near infrared (NIR) spectra of soil. The degree to which MC is restored depends on other soil properties, which are also affected by heating. We studied the effect of soil moisture on the estimation of the maximum temperature reached (MTR) in the soil using NIR spectroscopy. Different pre-treatments of burned samples were applied to modify MC. Different models relating NIR spectra with MTR were developed using partial least squares (PLS) regressions for the different pre-treatments. Models were successfully leave-one-out cross-validated with r2 greater than 0.982 and with the root mean square error of cross-validation (RMSECV) smaller than 28.2 °C. These models were used to predict the MTR for an independent set of soil samples heated at seven temperatures of 100, 200, 300, 400, 500, 600 and 700 °C. The MC of this set of samples was also modified using similar pre-treatments. Accurate estimations of MTR were obtained when the pre-treatment of samples used was similar as that of the set of samples used in the calibration model. Although MC of burned soils can affect MTR estimations, MTR can be estimated using NIR with high accuracy. Each heating temperature produced a gradient of changes leading to different NIR spectra that was not solely due to changes in soil moisture. This fact allows MTR to be estimated from NIR spectra.
Abstract: A field experiment was carried out in a semiarid agricultural Mediterranean area located at the "El Teularet" experimental field in the Enguera Sierra (Valencia, southeast Spain) to assess the influence of different agricultural management systems on indicators of soil biological quality and activity (microbial biomass C, basal respiration, C mineralization coefficients, metabolic quotient (qCO2), respiratory quotient (RQ: moles CO2 evolved/moles O2 consumed), soluble C and dehydrogenase, urease, protease-BAA, phosphatase and [beta]-glucosidase activities), one year after treatment establishment. The management practices assayed were as follows: application of the herbicides paraquat, glyphosate or oxyfluorfen, addition of olive tree pruning residues, ploughing, sowing of oats + addition of crop residues + ploughing, sowing of Medicago sativa, sowing of oats and vetch + addition of crop residues and addition of oat straw. A non-treated plot was used as control soil and a plot under natural vegetation was used as a standard of local, high quality soil. The plots with addition of oat straw had higher values of enzymatic activity, microbial biomass and respiration, reaching similar values to soil under native vegetation. The lowest levels of soil biological quality indicators were observed in the plots with application of some type of herbicide. Low RQ values were observed in these plots as consequence of the scarce-null inputs of organic matter, suggesting an increase in organic matter recalcitrance. The addition of oat straw to soil can be considered an effective technology, due to the rapid improvement of soil quality, for carrying out sustainable agriculture in semiarid Mediterranean agroecosystems.
Abstract: Near infrared reflectance (NIR) spectroscopy has many advantages because it is a rapid and cost-effective technique. A needed steep is the development of soil spectral libraries and models (calibrations using multivariate techniques). The calibrations should contain the variability of the target site soils on which the models are to be used. Many times this premise is not easy to fulfil. A classical way to solve this problem is by the spiking of models with a few samples from the target site (local samples), and the subsequent recalibration of models. In this regional-scale study we hypothesized that small-sized models should integrate the spectral characteristics of local samples more easily than large-sized models and as consequence should produce more accurate predictions. With the aim to test this hypothesis different-sized models were constructed using different quantities of soil samples. Partial least squares (PLS) regression was used to construct the models which were relating NIR spectra to the Nitrogen Kjeldahl (NKj) contents in soil samples. Two strategies were used for the selection of samples in models: (i) strategy based on spectra characteristics (SC) and (ii) strategy based on NKj values (NV) of the samples. These different-sized models were sequentially spiked with local samples from target sites and recalibrated. The predictions accuracies obtained with the models before and after spiking were studied being the NKj the soil property selected. In general all predictions were very accurate including those obtained before the spiking of models. Predictions accuracy increased as consequence of spiking in three of the four target sites studied. A negative trend was observed between prediction accuracy and model size. The lower errors were obtained using small-sized models after spiking which were more accurate than local models too. It was noticeable the high accuracy obtained by local models which were constructed using only 20 local samples. Before spiking SC models were more accurate than NV models but scarce differences between both strategies were observed after spiking with 20 samples. The results suggested that small-sized models can be useful for local predictions after spiking and they were also emphasizing the relevant role of local samples in models. The results obtained could encourage the expansion of this technique because large data based seem not be needed. Therefore NIR users could primarily focus most of their efforts on obtaining highly accurate analytical values in a few set of samples.
Abstract: Four different methods for analysing land-use and land-cover fractions at multiple scales, namely composite operator, <i>t</i>-test, Dutilleul's modified <i>t</i>-test and ternary diagrams of physical models for process pathways, were applied to sets of multi-resolution images in order to evaluate the usefulness of coarse-resolution satellite data (e.g. the Moderate Resolution Imaging Spectroradiometer; MODIS) in obtaining similar results to those obtainable with moderate-resolution satellite data (e.g. Landsat). A spectral-mixture model based on three endmembers (soil, vegetation and water) was used to determine the land-cover fractions of the main land-use classes of a wetland in southeast Spain. The land-use map was produced by applying the unsupervised <i>k</i>-means classification method to the moderate-resolution image. Spatial and temporal changes in the mixture fractions at multiple resolutions and their corresponding land-cover fraction maps were assessed. Three different <i>t</i>-tests (paired-samples, independent-samples and Dutilleul's modified <i>t</i>-tests) were used to evaluate the effects of pixel aggregation on land-cover fractions and land-use maps in terms of surface-area estimations. Ternary plots of land-use classes characterized by land-cover fractions were used to visualize environmental processes pathways describing temporal changes in the landscape. The results obtained with moderate- and coarse-resolution data were not significantly different from each other. Land-use and land-cover surface-area estimations were not significantly different between Landsat moderate-resolution (30 m) and Landsat resampled coarse-resolution (300 m) data. Spatial autocorrelation had an important effect when comparing Landsat moderate-resolution (30 m) with MODIS coarse-resolution (250 m) data. In order to minimize these effects Dutilleul's modified <i>t</i>-test was applied for the comparison of Landsat with MODIS image data. However, this test did not reveal significant differences between both datasets, whereas with the ordinary <i>t</i>-test, significant differences were found, which suggest the existence of a bias by spatial autocorrelation that must be taken into account for up-scaling or down-scaling of remote-sensing data. The results suggest the possibility of using coarse-resolution images (MODIS) to characterize environmental changes with a similar accuracy to those of moderate-resolution images (Landsat), as long as potential spatial autocorrelation effects are taken into account. This finding indicates that a substantial reduction in the costs of conducting wetland management and monitoring tasks can be achieved by using free or low-cost coarse-resolution satellite images.
Abstract: Since the beginning of the twentieth century, the province of Castellón, in eastern Spain, has been one of the most important areas of floor and wall tile production on both a national and worldwide scale. As a result of this sectorâs productive rate of development (in the 1970â2005 interval), a series of pollution-producing chemical substances has been introduced into the atmosphere. The objective of this study is the comparison between industrialâurban and rural zones in this province, with the goal of establishing the causes of the contamination in order to apply corrective measures upon the different emission sources. Sustainable development is sought after to guarantee that, in the future, the environmental quality parameters fall within legal limits, ensuring the populationâs well-being as well as conserving natural ecosystems and material assets. Total suspended particles and PM10 are the parameters studied. The reason for choosing this pollutant type is because particulate matter may present a much higher potential risk despite its low representativeness as compared to the gas pollutantâs group. A positive correlation between high particle concentrations and deterioration in public health has been shown in recent studies. The elements As, Cd, Ni, and Pb in PM10 were also analyzed to determine the toxicity of these particles. This study has demonstrated the different behaviors of the parameters studied at different types of stations (industrialâurban and rural), leading to the conclusion that anthropogenic factors are very important in the area studied and that they determine the areaâs air quality to a great extent.
Abstract: Heavy metals can be transferred from soils to other ecosystem parts and affect ecosystems and human health through the food chain. Today the use of biosolids to improve the nutrient contents of a soil is a common practice. Contamination of soils by potentially toxic elements (e.g., Cd, Ni, Cr, Pb) from amendments of biosolids is subject to strict controls within the European Community in relation to total permissible metal concentrations, soil properties and intended use. In this context, heavy metal concentrations were studied in agricultural soils devoted to vegetable crops in the province of Alicante (SE Spain), where an intensive agriculture takes place. This study is aimed at ascertaining the chemical partitioning of Cd, Ni, Cr, and Pb in agricultural soils repeatedly amended with sludge. Selected soil properties relevant to control the mobility and bioavaibility of heavy metals were analyzed for the general characterisation of these agricultural soils. The distribution of chemical forms of Cd, Ni, Cr, and Pb in five biosolids-amended soils was studied using a sequential extraction procedure that fractionates the metal into soluble-exchangeable, specifically sorbed-carbonate bound, oxidizable, reducible, and residual forms. The biosolids incorporation has modified the soil composition, leading to the increment of heavy metals. The residual, reducible, and carbonate-sorbed forms were dominant. Detailed knowledge of the soil at the application site, especially pH, CEC, buffering capacity, organic matter, clay minerals, and clay content, is essential.
Abstract: In semiarid ecosystems plant cover plays an important role in the improvement of physical, chemical and biochemical soil properties. With the aim of studying the influence of different plant species on soil properties, and establishing the relationships between them, 160 soil samples from under four different plant species (Pinus halepensis, Quercus coccifera, Juniperus oxycedrus and Rosmarinus officinalis) were taken in a forest area of the province of Alicante (SE Spain). The following soil properties were analyzed in all soil samples: organic carbon content, microbial biomass, soluble organic carbon, aggregate stability, basal respiration, and some eco-physiological ratios. In addition, the near infrared spectra (NIR) of all soil samples were obtained to verify the similarities or differences between soil samples under the four species. Some differences in parameters such as organic carbon content or basal respiration were found mainly between the group of P. halepensis and Q. coccifera with respect to J. oxycedrus and R. officinalis. Despite this, the high organic carbon content found under the four plant species showed an influence on the rest of soil properties. Moreover, using a discriminant analysis with factorial scores from NIR absorbance data did not result in a good classification of samples in terms of the species, reflecting some similarities between them. Our results show that the high contents observed in some parameters under the four species, and the lack of significant differences in most of them, prove the important role of shrubland in semiarid conditions, it being capable of promoting good soil conditions.
Abstract: The main aim of this study was to compare the suitability of three single chemical extractants [EDTA, CaCl2 and the low-molecular-weight organic acids solution (LMWOAs)] to estimate Cu, Zn and Ni uptake by barley (Hordeum vulgare) from rhizosphere soils, following a single application of a metal salts-spiked sewage sludge. Thirty-six contrasting soils from different parts of Spain were amended with the same dose (15.71Â g dry weight kg-1) of polluted sewage sludge and sown with barley seeds under greenhouse conditions. Eight weeks after sowing, the plants were harvested and Cu, Zn and Ni were analysed in the roots. Heavy metal uptake was then compared with the theoretically available heavy metals in the rhizosphere soils, assessed by the three single chemical extractants. These three extractants alone failed to predict heavy metal uptake, and soil properties were needed to obtain accurate predictions. Thus, none of the methods tested in this study can be used as a universal soil extraction for estimating Cu, Zn and Ni uptake by barley.
Abstract: The main objective of this study was to compare the effectiveness of different methods (heavy metals in pore water (PW), diffusive gradients in thin films (DGT), diethylene triamine pentaacetic acid (DTPA) extraction, and total heavy metals (THM) in soil) for the assessment of heavy metal bioavailability from soils having various properties and heavy metal contents. The effect of soil heavy metal pollution on shoot yield and sulfatase enzyme activity was also studied. Wheat (Triticum aestivum) was grown in different soils from Spain (nâ=â10) and New Zealand (nâ=â20) in a constant environment room for 25Â days. The bioavailabilities of Cd, Cr, Cu, Ni, Pb, and Zn were assessed by comparing the metal contents extracted by the different methods with those found in the roots. The most widely applicable method was DGT, as satisfactory Cu, Ni, Pb, and Zn root concentrations were obtained, and it was able to distinguish between low and high Cr values. The analysis of the metal concentrations in PW was effective for the determination of Cr, Ni, and Zn content in root. Copper and Pb root concentrations were satisfactorily assessed by DTPA extraction, but the method was less successful with determining the Ni and Cr contents and suitable just to distinguish between high and low concentrations of Zn. The THM in soil method satisfactorily predicted Cu and Pb root concentrations but could only be used to distinguish between low and high Cr and Zn values. The Cd root concentration was not successfully predicted for any of the used methods. Neither shoot yield nor sulfatase enzyme activity was affected by the metal concentrations.
Abstract: Abstract Coal mine restoration projects increase public perception of mining companies. Spain has relatively few examples of completed opencast mine rehabilitation projects. This study seeks to obtain the use of mine spoils from coal mines in Teruel. The studied mine spoils may be used as raw material for the Spanish ceramic industry, located in the provinces of Castellon, Valencia and Teruel. This study specifically discusses the mineralogical and geochemical characteristics of the Lower Cretaceous materials from coal deposits in Estercuel basin, around Teruel and Castellon in Spain. These provinces have a large ceramic industry. A characterization of mine spoils from coal deposits has been carried out. This characterization is based on the data of both mineral and chemical analysis. The mineralogical characterization was complemented with SEM/EDAX. The study of the chemical composition allows the evaluation of the applicability of the studied mine spoils to the following industries: refractory, fine clay, red clay for pavement and coating, and heavy clay. The clay used for refractory industry has the highest compositional demand. The positive results obtained on this set of preliminary tests lead us to envisage new research programs, focusing on testing these mine spoils on a semi-industrial scale.
Abstract: Heavy metals can be transferred from soils to other portions of the ecosystem, with effects at both the ecosystem level and on human health from transmission through the web chain. For several years, this environmental issue has concerned scientists. In this context, heavy metal concentrations were studied in agricultural soils devoted to vegetable crops in the province of Castellon (NE Spain), in areas of intensive agriculture. Currently, the use of biosolids to improve the nutrient contents of the soil is a common practice. Contamination of soils by potentially toxic elements (e.g., Cd, Ni, Cr, Pb) from amendments of biosolids is subject to strict controls in relationship to total permissible metal concentrations, soil properties, and intended use within the European Community. This study is aimed at determining the chemical partitioning of Cd, Ni, Cr, and Pb in agricultural soils repeatedly amended with sludge. The distribution of chemical forms of Cd, Ni, Cr, and Pb in five biosolids-amended soils was studied using a sequential extraction procedure that fractionated the metal into soluble-exchangeable, specifically sorbed-carbonate bound, oxidizable, reducible, and residual forms. The biosolids incorporation has modified the soil composition, leading to the increment of heavy metals. The residual, reducible, and carbonate-sorbed forms were dominant. The mineralogical association of the clay fraction was illite, kaolinite, and chlorite. (C) 2009 Lippincott Williams & Wilkins, Inc.
Abstract: Abstract This paper shows a contribution to the knowledge of the geological management of ceramic raw material. We have mainly focussed on the clays with a ceramic interest. The article begins with an introduction to the mineralogical determining factor of the ceramic sector. Then, it shows a development of the main steps that take place in the geological prospecting and it concludes with the criteria that must be followed when selecting the outcrops: geographical and environmental conditions, (1) legislation, (2) market and technology, (3) mineralogical and technological characterisation and (4) geological and mining characterisation.
Abstract: Soil biochemical properties are susceptible to change under sample storage, and as a consequence, these properties have usually been determined in fresh samples, kept cold or frozen for brief periods of time. However, air-dried soil would facilitate routine soil testing procedures in soils from semi-arid Mediterranean areas, which have soil water deficit most of the year. This research aims at assessing the effects of medium-term soil storage (6-9 months) at room temperature on air-dried soil samples from two Mediterranean forest locations for the measurement of various microbiological and biochemical properties (microbial biomass carbon, basal respiration, metabolic quotient, acid phosphatase activity, urease activiy, β-glucosidase activity, and soluble carbon). Storage of air-dried soil samples for 6 months had no significant effects on the studied properties in any location. With regard to samples stored for 9 months, we only found differences at the location with higher mean rainfall in the values of basal respiration, the metabolic quotient and β-glucosidase, and urease activities. Our results show that biochemical properties from Mediterranean semi-arid soils, are medium-term stable in stored air-dried soil samples. Thus, these findings would encourage the selection of biochemical properties on a practical basis, as there is no strict requirement to determine these properties immediately after sampling, as they remain valid for several months.
Abstract: Sierra de Callosa have an area of 8 km2 and a maximum altitude of 566 masl. Geologically, it is found to be primarily comprised of carbonated rocks. Mine spoils coming from limestone quarries extraction are often used in the working reclamation process. These materials could be actually employed profitably once conveniently amended with organic matter. A study on the temporary evolution of nutrients and several physicalâchemical parameters in a mineral waste amended with municipal solid waste (MSW) compost has been carried out. The effect of incorporating such waste to mine spoils in an arid gravel quarry has been studied, quantifying the temporal evolution of nutrients and several physicalâchemical parameters in the mixture. Three plots have been prepared with mine spoils proceeding from a limestone quarry located in the south of the province of Alicante (municipality of Redován). These plots have been amended with 3 kg/m2 of MSW compost. Texture, pH, electrical conductivity, oxidizable organic matter, N-Kjeldahl, available P, Na, K, Ca, Mg, Fe, Mn, Cu and Zn were analysed. The results reflected the contribution of nutrients to the substrate after the MSW addition. The variability of the information indicated the heterogeneity of the MSW composition, as well as the difficulty of obtaining a homogeneous MSW mixtureâmineral waste.
Abstract: In Eastern Spain, almond trees have been cultivated in terraced orchards for centuries, forming an integral part of the Mediterranean forest scene. In the last decades, orchards have been abandoned due to changes in society. This study investigates effects of changes in land use from forest to agricultural land and the posterior land abandonment on soil microbial community, and the influence of soil physico-chemical properties on the microbial community composition (assessed as abundances of phospholipids fatty acids, PLFA). For this purpose, three land uses (forest, agricultural and abandoned agricultural) at four locations in SE Spain were selected. Multivariate analysis showed a substantial level of differentiation in microbial community structure according to land use. The microbial communities of forest soils were highly associated with soil organic matter content. However, we have not found any physical or chemical soil property capable of explaining the differences between agricultural and abandoned agricultural soils. Thus, it was suggested that the cessation of the perturbation caused by agriculture and shifts in vegetation may have led to changes in the microbial community structure. PLFAs indicative of fungi and ratio of fungal to bacterial PLFAs were higher in abandoned agricultural soils, whereas the relative abundance of bacteria was higher in agricultural soils. Actinomycetes were generally lower in abandoned agricultural soils, while the proportions of vesicularâarbuscular mycorrhyzal fungi were, as a general trend, higher in agricultural and abandoned agricultural soils than in forests. Total microbial biomass and richness increased as agricultural < abandoned agricultural < forest soils.
Abstract: Abstract The constructions of Cultural and Architecture Patrimony are influenced by pollutants. Many of degenerative processes in the materials which constitute them have their origin in pollutants. That is the reason why a physicalâÂÂchemical characterisation of the particulate pollutants in the air has been carried out. The deposition and, as a consequence of that, the interaction of the pollutants with the different materials of the monuments depend on the reactivity of the chemical elements that form the atmospheric particulate. Studies of both, bulk dust deposition and total suspended matter, a mineralogical and chemical characterisation of them have been made. Lastly, starting from these data, it can be established that the interactions and degenerative processes are taking place in the monuments of the studied locations. In the present work, the methodology carried out in the study of the particulate atmospheric pollutants, which are capable of accumulating on monuments and buildings with artistic and historical interest in the area of Castellon, is displayed. By means of a network of captors, important samples of sedimentary and suspension atmospheric pollutants, total suspension particles (TSP) were obtained. Firstly, by gravimetric methods, we have obtained the concentration levels of these kinds of pollutants in milligrams per day in busk dust samples and micrograms per cubic meter in TSP. Due to the fact that the corrosivity of these pollutants fundamentally depends on their compositions, the study has been completed with a mineralogical and chemical characterisation. By X-ray diffraction and scanning electron microscopy, we have analysed the particles of the two kinds of samples. The chemical analysis was carried out by inductively coupled plasma-atomic spectroscopy and inductively coupled plasma-mass spectrometry (multielement analysis techniques) in TSP samples and in the soluble fraction of the depositing particulate matter. The results have shown as main compounds: clay minerals, calcite, and carbonaceous matter coming from non-perfect combustion of vehicles. The chemical analysis indicates a high Ca/S ratio and high levels of concentration in chemical elements associated to this representative industrial cluster of ceramics industry in Europe.
Abstract: In Spain, agriculture triggers soil degradation and erosion processes. New strategies have to be developed to reduce soil losses and recover or maintain soil functionality in order to achieve a sustainable agriculture. An experiment was designed to evaluate the effect of different agricultural management on soil properties and soil erosion. Five different treatments (ploughing, herbicide, control, straw mulch and chipped pruned branches) were established in âEl Teularet experimental stationâ located in the Sierra de Enguera (Valencia, Spain). Soil sampling was conducted prior to treatment establishment, and again after 16 months, to determine soil organic matter content (OM), aggregate stability (AS), and microbial biomass carbon content (Cmic). Fifty rainfall simulations tests (55 mm during one hour, 5-year return period) were applied to measure soil and water losses under each treatment. The highest values of OM, AS and Cmic were observed in the straw-covered plot, where soil and water losses were negligible. On the contrary, the plot treated with herbicides had the highest soil losses and a slight reduction in Cmic. Soil erosion control was effective after 16 months on the plots where vegetation was present while on the ploughed and herbicide-treated plots, the practices were not sustainable due to large water and soil losses. Except for the straw mulch plot, soil properties (OM, AS, Cmic) were not enhanced by the new land managements, but soil erosion control was achieved on three of the five plots used (weeds, weeds plus straw and weeds plus chipped pruned branches). Erosion control strategies such as weeds, weeds plus straw mulch and weeds plus chipped branches mulch are highly efficient in reducing soil losses on traditional herbicide-treated and ploughed agricultural land. However, it takes longer to recover other soil properties such as OM, AS, and Cmic.
Abstract: Alkaline soils are considered much less prone to developing water repellency induced by fire than acidic soils. Here we report on the persistence of water repellency present in calcareous soils immediately after wildfires in 10 burned areas in SE Spain, its distribution in different aggregate size fractions (< 2, 2â1, 1â0.5, 0.5â0.25 and < 0.25 mm) and on results from aggregate stability tests. We also distinguished between soil samples taken beneath pine (Pinus halepensis) and beneath understory vegetation.
Burning appears to have increased the frequency of water repellency occurrence, with 74% of burned samples being classified as water repellent compared to 33% from unburned terrain in the composite fraction (< 2 mm). The persistence of water repellency after fire was highly variable but nevertheless showed statistical differences at p < 0.001 comparing burned vs unburned. Moreover, statistical differences in the persistence of water repellency were found in soil samples taken from beneath pine between burned and unburned, and also beneath understory vegetation. Results showed that soil beneath understory tend to have lower values of water repellency persistence than soil beneath pine.
Burned soils showed higher aggregate stability. A positive tendency was observed between aggregate stability and water repellency. The observed changes in WR and AS could have implications for soil hydrological behaviour.
Abstract: The heat generated during wildfires often leads to increases in soil water repellency. Above a critical heating threshold, however, its destruction occurs. Although the temperature thresholds for repellency destruction are relatively well established, little is known about the specific changes in the soil organic matter that are responsible for repellency destruction. Here we report on the analysis of initially water repellent surface soil samples (Dystric Cambisol, 0â5 cm depth) by transmission Fourier Transform Infrared (FTIR) spectroscopy analysis before and after destruction of its water repellency by heating to 225 °C in order to investigate heating-induced changes in soil organic matter (SOM) composition. Although assignment of absorption bands is made difficult by overlapping of some bands, it was possible to distinguish bands relevant for hydrophobicity of SOM in the soil before heat treatment. The most significant decrease in absorbance following water repellency destruction took place in the frequency area corresponding to stretching vibrations of aliphatic structures within SOM. The results suggest that besides a general decrease of SOM content during heating, the loss of soil water repellence is primarily caused by the selective degradation of aliphatic structures.
Abstract: The potential of near infrared (NIR) reflectance spectroscopy to predict various physical, chemical and biochemical properties in Mediterranean soils from SE Spain was evaluated. Soil samples (n = 393) were obtained by sampling 13 locations during three years (2003â2005 period). These samples had a wide range of soil characteristics due to variations in land use, vegetation cover and specific climatic conditions. Biochemical properties also included microbial biomarkers based on phospholipid fatty acids (PLFA). Partial least squares (PLS) regression with cross validation was used to establish relationships between the NIR spectra and the reference data from physical, chemical and biochemical analyses. Based on the values of coefficient of determination (r2) and the ratio of standard deviation of validation set to root mean square error of cross validation (RPD), predicted results were evaluated as excellent (r2 > 0.90 and RPD > 3) for soil organic carbon, Kjeldahl nitrogen, soil moisture, cation exchange capacity, microbial biomass carbon, basal soil respiration, acid phosphatase activity, β-glucosidase activity and PLFA biomarkers for total bacteria, Gram-positive bacteria, actinomycetes, vesicular-arbuscular mycorrhizal fungi and total PLFA biomass. Good predictions (0.81 < r2 < 0.90 and 2.5 < RPD < 3) were obtained for exchangeable calcium and magnesium, water soluble carbon, water holding capacity and urease activity. Resultant models for protozoa and fungi were not accurate enough to satisfactorily estimate these variables, only permitting approximate predictions (0.66 < r2 < 0.80 and 2.0 < RPD < 2.5). Electrical conductivity, pH, exchangeable phosphorus and sodium, metabolic quotient and Gram-negative bacteria were poorly predicted (r2 < 0.66 and RPD < 2). Thus, the results obtained in this study reflect that NIR reflectance spectroscopy could be used as a rapid, inexpensive and non-destructive technique to predict some physical, chemical and biochemical soil properties for Mediterranean soils, including variables related to the composition of the soil microbial community composition.
Abstract: The aim of this work was to assess the effect of the presence of ash on maximum temperature reached (MTR) estimation using near infrared reflectance (NIR) spectroscopy. The degree of combustion (ash produced by heating to 100, 300, 500 and 700 °C), the type (ash from Pinus halepensis and Rosmarinus officinalis), and different quantities of ash (0â20% in 2% interval) were evaluated in a soil heated at seven different temperatures (100 °Câ700 °C). Results showed that the estimation of MTR on samples with ash, using partial least squares (PLS) models constructed with samples without ash, could be erroneous. Both, ash quantity and degree of combustion affected the estimation of MTR. However, using discriminant analysis, a good classification of samples (> 97% correctly classified) according to the heating temperature classes (unheated, 100, 200, 300, 400, 500, 600 and 700 °C) was obtained despite the presence of ash.
Abstract: Mediterranean soils are critically endangered by natural and human induced degradation processes. Rapid and cost effective techniques for in situ diagnosis of soil properties are highly valuable for soil assessment and management studies. The combined use of remote sensing techniques and Geographic Information Systems (GIS) has introduced a new era for soil resources assessment and monitoring. This work deals with soils in SE Spain and explores the use of spectral derivative analysis to predict several soil properties using field based visible-near infrared (VNIR) spectroradiometry. Robust regression models were obtained for electric conductivity (E.C.), carbonates, soil organic matter (SOM) and sand content with the first and/or second derivative approximation. Future research stages will include evaluating the technique presented in this paper for other semi-arid soils and scaling-up field based regression model predictions for soil properties to the resolution of satellite remote sensors.
Abstract: The ecologic restoration criteria in areas degraded from extraction activities require making use of their mine spoils. These materials do not meet fertility conditions to guarantee restoration success and therefore, need the incorporation of organic amendments to obtain efficient substratum. Reducing the deficiencies in the organic material and restoration material nutrients with the contribution of treated sewage sludge is proposed in this work. This experiment was based on a controlled study using columns. The work was conducted with two mine spoils, both very rich in calcium carbonate. The first mineral, of poor quality, came from the formation of aggregates of crushed limestone (Z). The other residual material examined originated in limestone extraction, formed by the levels of interspersed non-limestone materials and the remains of stripped soils (D). Two treatments were undertaken (30,000 and 90,000 kg/ha of sewage sludge), in addition to a control treatment. The water contribution was carried out with a device that simulated either short-duration rain or a flooding irrigation system in order to cover the surface and then percolate through the soil. The collection of leached water took place 24 h after the applications. Different parameters of the leached water were determined, including pH, electrical conductivity, nitrate anions, ammonium, phosphates, sulphates and chlorides. The values obtained for each irrigation application are discussed, and the nitrate values obtained were very elevated.
Abstract: This study is focussed on the behaviour of ceramic clays from the area around Castellon (Spain) having a large ceramic industry. Test samples have been prepared by extrusion and firing in the range of 800â1150 °C. Analysis of the fired samples was carried out by X-ray diffraction. The results from the study of mineralogical transformations show the persistence of illite up to at least 900 °C. From the destruction of illite, an intermediate phase between spinel and hercynite originates. Mixtures of illitic clays containing CaCO3 form gehlenite, wollastonite and anorthitic plagioclases from 950 °C onwards. Quartz and hematites are present in samples poor in CaCO3. The optimum firing temperature for each sample has been established. The maximum bending strength of each ceramic body has been determined. Porosity-strength relations have been established.
Abstract: Soils from natural ecosystems have specific physical, chemical and biochemical properties determined by the conditions in which these soils have developed. These soils that develop without external disturbance reach a balance amongst their properties. Thus, the creation of a model that represents the established balance of different soil properties from stable ecosystems can be used as a soil quality index, thus any perturbation must lead to modifications in this natural balance. Two regression models with soils from undisturbed forest regions in eastern Spain were previously developed, representing the balance between organic carbon and some physical, chemical and biochemical properties. For undisturbed forest soils, the prediction of soil organic carbon (SOCc) with the calibrated models should be similar to the actual value of this variable (SOCa) (SOCc â SOCa). Consequently, the residuals (SOCc â SOCa) should be around 0. On the contrary, disturbance practices cause a disruption in the balance defined between the different properties and SOC. As a consequence, residuals must be < or >0. Furthermore, the more the degree of degradation increases, the more the values of SOCc must differ from the values of SOCa. According to this, two soil quality indices (SQI) were defined, one for each model, by the calculation of the model residuals (SQI = SOCc â SOCa). The SQIs have been applied to different undisturbed forest soils to evaluate their validity. In addition, they have also been applied to severely altered soils, like agricultural soils, and abandoned agricultural fields, to assess the sensibility of this index to perturbations. After applying the soil quality indices to eleven undisturbed forest soils, it has been verified that a balance exists between organic matter content and different physical, chemical and biochemical properties in forest soils from SE Spain, and the proposed calibrated models are capable of reflecting that balance (SQI â 0). Our results confirm that our models are sensitive to soil perturbation, because agricultural and abandoned agricultural soils have shown an imbalance between organic carbon content and the physical, chemical and biochemical properties (SQI > 0). Moreover, soils from abandoned fields showed lower deviation in the natural equilibrium, indicating a recovery of soil quality.
Abstract: Fire usually induces water repellency (WR) in soils. Reduction in infiltration rates, increase of runoff and erosion are some of the consequences of WR in fire-affected soils. Most forest soils can develop WR by burning; however some previous observations in burned terra rossa soils have shown little changes in WR. Laboratory controlled experiments have been done with samples of terra rossa from 14 different sites. The objectives are to confirm whether the observed is a common behaviour of terra rossa and to explore the factors controlling the wettability of this soil type after burning. Samples from the upper 2.5 cm of terra rossa were collected from 12 forest sites of the Alicante province (Spain), and from 2 sites in the âMt. Carmelâ, Haifa (Israel) with similar environmental conditions. Laboratory burning of samples at 250 °C, 300 °C and 350 °C was performed with and without the addition of litter of Pinus halepensis. The results confirm that all soils have a very low susceptibility to become water repellent by burning. Without the addition of litter, WR was not detected in any soil sample at any temperature of burning. With the addition of litter, WR was present only in six of the soils after some of the heating treatments. Although all soils had enough soil organic matter (SOM) to develop WR by heating, the ratio between SOM and clay content was considerably lower compared to other types of forest soils of the region in which WR has been found after forest fires. This could explain in part the lower susceptibility of terra rossa to become water repellent by burning since, as some authors have indicated, fine-textured soils are less prone to develop soil WR due to their high specific surface area. From mineralogical analysis of the clay fraction we found that the dominant clay types in the studied terra rossa were kaolinite and illite, with the exception of one soil where Caâmontmorillonite content is higher than kaolinite and illite. Caâmontmorillonite was present in only three of the soils. Comparing the soil properties between the group of terra rossa that in no case become water repellent (wettables) with the group that in some cases developed WR (potentially water repellents), some differences were found: the kaolinite content is higher in the wettables group (P < 0.05), and the soils containing Caâmontmorillonite are in the group of potentially water repellents. A clear separation between the 2 groups was found when we compared SOM vs kaolinite contents, the kaolinite content being the main factor contributing to this separation. These results are in agreement with those obtained in experiments with clay additions to water repellent soils in order to reduce the WR, and also with some studies which found that kaolinite is one of the most effective clay minerals for this purpose.
Abstract: Abstract In southern Chile, with a mild and rainy climate, high levels of heavy metals have been detected in many gold placer deposits. Many of the contaminants pose risks to human life, and consequently damage the trofic chain in this environment. The study zones selected correspond to the handicraft gold-bearing sands of Rio Gato (Los Muermos), Carelmapu and Cucao. These are all located in the X Region of âÂÂLos Lagosâ in Chile. The type of methodology used in the characterization of the associated mineralization consists of testing each representative sample with a grain size distribution, statistical parameter analysis and a mineralogical analysis, using a binocular magnifying glass, a petrographic microscope, XRD and SEM/EDX. The chemical composition was defined by means of X ray fluorescence and micro-chemical analysis. The results of the study about sediments in southern Chile are presented. The major concentrations of heavy minerals are generally located in areas of dynamic river energy. In the samples, more than 70% of the heavy minerals were distributed among grain sizes corresponding to thin sand with good grain selection (meshes of 0.25âÂÂ0.06 mm). The main mineral phases present in the analysed samples were gold, zircon, olivine, ilmenite, hornblende, hypersthene, hematite, garnet, chromite, chlorite, augite, amphibolitic-epidote, etc. The main heavy metals found as a result of the study were mercury, lead, cadmium, chrome, tellurium, indium, zinc, cobalt, copper, platinum, gold, etc., and as well some less common elements like cerium, praseodymium, gadolinium, neodymium, samarium and lanthanum. This research work is only a starting point for carrying out a risk probability mapping of heavy metals and the mineralogy of the Cucao, Carelmapu and Rio Gato gold-bearing sands.
Abstract: Abstract The study area is highly industrialized, with businesses involved in the non-metal mineral products sector and ceramic industries (colors, frits and enamel manufacturing) standing out. Air quality evaluation was performed regarding atmospheric particles (PM10 fraction) and Pb in a Spanish coastal area during 2001 and 2002 in order to compare these values with other areas in the Mediterranean basin. Once the samples were collected, their PM10 fraction concentration levels were determined gravimetrically. A Pb analysis in air pollution filters was carried out by ICP-MS. The seasonal and weekly variabilities of these contaminants were also studied, with the objective of being able to explain their origin and thus minimize their possible damaging effects. A similar evolution of PM10 and Pb was observed in both years of the study. Higher PM10 concentrations have been detected during the months of June and July, lower values between MarchâÂÂMay, August and OctoberâÂÂDecember, and intermediate values in January and February. A similar tendency has been observed by other authors in European industrialized cities. Regarding Pb, the monthly mean remains constant during the entire year. In the study area, Pb represents 0.6% as a mean of the total PM10 mass, with a variation range between 0.1 and 5.1%. The major crystalline phases in PM10 were quartz, calcite, dolomite, illite, kaolinite and feldspars.
Abstract: Water repellency (WR) is a property that has implications on the hydrologic balance in affected soils. In semi-arid areas where water supply is limited, even slight WR may play an important role in the infiltration and spatial distribution of precipitation into the soil. Acidic and sandy-textured soils have been demonstrated to be more prone to develop WR, but there are studies reporting water repellent properties in other soil types. In the present study we investigated soil WR under four plant species in a semi-arid area with a calcareous, medium-textured forest soil. For this purpose, 160 soil samples were taken at micro-sites under different species (Pinus halepensis, Quercus coccifera, Juniperus oxycedrus and Rosmarinus officinalis). Soil WR was measured with the water drop penetration time (WDPT) test on air-dried samples. Samples with WDPT > 5 s were classified as water repellent. WR was present in 20% of the samples, and its persistence ranged mainly between 10 and 30 s. Under P. halepensis and Q. coccifera, WR occurred more frequently (40 and 30%, respectively) than under J. oxycedrus and R. officinalis (only 5% in both cases). In order to know the causes of the difference in occurrence of WR under the selected species and to establish relationships, soil organic matter (SOM) content and pH were measured for a selection of 66 samples, including all 32 water repellent and 34 wettable samples selected from those taken under the four species (n = 66). A negative relationship between WR and pH was found for all species. Moreover, in the case of P. halepensis soil samples, a positive correlation between WR and SOM content was found. A discriminant analysis allowed for the distinction between water repellent and wettable conditions in calcareous soils, based on the information provided by pH, SOM content and vegetation type. Soil pH turned out to be the most important parameter for discrimination. The hydrological and ecological implications from these results are discussed with special focus on the areas in the region extensively afforested with P. halepensis.
Abstract: We studied the use of near-infrared (NIR) reflectance spectroscopy as a potential method to estimate a posteriori the maximum temperatures reached (MTR) on burned soils. When soils are heated, the NIR spectra change in accordance with the MTR. Thus, after calibrating, these patterns of NIR could be used as a fingerprint to estimate the MTR in burned soils. Successful validations of the models relating NIR spectra with MTR were obtained in each of the five soils studied (local models), with r2 values ranging from 97.47 to 98.56%. A global model constructed with samples from the five soils studied obtained a similar accuracy, suggesting the presence in soils of some NIR-detectable compounds with similar thermal sensitivity. The influence of the variability caused by the soil type and the duration of heating during model constructions is also evaluated and discussed. The use of NIR presents interesting advantages, such as low cost, low time consumption, minimal pretreatment of samples, no need for chemicals, and accuracy. The results indicate that the MTR could be estimated in burned soils with NIR, offering a new perspective on studies of wildfire effects on soils.
Abstract: Soil biochemical properties are useful indicators of soil quality as they are very sensitive to disturbance. Sample storage or pre-treatments could affect the results in these assays, which are normally determined on fresh samples, kept cold or frozen. The objectives of this study were to (i) evaluate the effect of air-drying or incubation of rewetted air-dried soil samples on microbial biomass carbon (MBC), basal soil respiration (BSR), qCO2 and water soluble carbon (WSC), in soils from different locations, with different degradation status and sampling seasons, and (ii) assess if air-drying or incubation of rewetted air-dried soil samples is an accurate sample storage and pre-treatment procedure for these soil properties in soil quality evaluations under semiarid Mediterranean conditions. Our results showed that air-drying does not have the same effects on MBC, BSR, qCO2 and WSC depending on the geographical situation and sampling date. It seems that the warmest and driest place and season show less variation when using air-dried soil samples, with values representative of those obtained under field-moist conditions. Short incubations (4, 8 and 12 days at 23 °C) provoked a general decrease in all properties, probably due to labile organic compounds depletion. Hence, air-dried soils can be used as part of soil quality analysis to estimate these biochemical properties in summer time in the semiarid region of South-East Spain, because they have not suffered severe affections. Moreover, MBC could also be determined using air-dried soil in the driest zones during all year. In contrast, estimations with incubated soil samples are not, in any case, representative of field-moist soil values.
Abstract: Abstract The main objective of this paper is to check the fulfilment of the European Directive 2004/107/CE, which refers to the limit values of arsenic, cadmium and nickel that will have to be carried out the first of January 2010. Three sampling points have been chosen (Alcora, Vila-real and Castelln), forming a triangle that comprise most of the ceramic cluster of the province of Castelln (Spain). This is a problematic area in relation to the fulfilment of the directive, due to its high industrial development. Apart from this main objective, the following are raised: a) The analysis of the temporal evolution of the levels of As, Cd, Ni and PM10 in the atmosphere during the year 2002; b) The identification of similar behaviour patterns and of the possible common origins in the studied pollutants; c) To show the existence of differences in the behaviour and evolution of As, Cd, Ni and PM10 in the atmospheric medium depending on the location of the sampling point; d) To check whether the levels of As, Cd, Ni and PM10 are influenced by the environmental temperature. The concentration levels of arsenic, cadmium and nickel in Alcora, Vila-real and Castelln have been determined during the year 2002, in order to check whether they are below the limits established in the future directive on these elements. The following conclusions are reached from the results obtained after the chemical analysis (using ICPâÂÂMS) of the samples collected in the three locations.
Abstract: For millennia, land use in the Mediterranean region has led to situations in which soil has been severely degraded showing high risks of erosion and impoverishment. Thus, the establishment of soil quality indices is considered to be of crucial importance in determining the state of degradation and recovery of soils. Soils from stable forest ecosystems have specific physical, chemical and biological properties due to the conditions in which they developed. Hence, modelling the balance established among different key soil properties from stable forest ecosystems could be used as a soil quality index, because disturbance practices lead to changes in that natural balance. Here we report the establishment of two soil quality indices under Mediterranean semiarid conditions for forest soils in SE Spain, based on the use of multiple linear regressions integrating different physical, chemical and biochemical properties. As we observed the strong influence that climatic factors have on the values of the different soil properties and their relationships, mean annual precipitation was also incorporated in the regression models as a categorical explanatory variable. Model 1, that explains 92% of the variance in soil organic carbon (SOC), showed that SOC can be calculated by a linear combination of 6 physical, chemical and biochemical properties (acid phosphatase, water holding capacity (WHC), electrical conductivity (EC), available phosphorus (P), cation exchange capacity (CEC) and aggregate stability (AS)). Model 2 explains 89% of the variance in SOC, which can be calculated by means of 7 chemical and biochemical properties (urease, phosphatase and β-glucosidase activities, pH, EC, P and CEC). Our results confirm that a balance exists between the soil organic carbon of high quality soils and some other properties widely recognised in soil quality assessments, due to their sensitivity and the information they provide about the functionality of soils. As disturbance practices should be accompanied by the loss of this balance, SOC calculated by the models (SOCc) is no longer an accurate estimation of the actual SOC determined in laboratory (SOCa). Thus, it is possible to obtain a soil quality index by the calculation of the model residuals: Soil Quality Index = model residual = SOCc â SOCa. For a non-disturbed soil, the soil quality index should be 0 (SOCc = SOCa). In contrast, for disturbed soils, SOCc should be lower or higher than the actual SOC, with values in the soil quality index < 0 or > 0.
Abstract: Water repellency (WR) is a property affected by fire and of crucial importance in the hydrological behaviour of soils after burning. In dry Mediterranean areas knowledge of the factors that control the development of water repellency by fire is of particular interest. We examined such factors in two calcareous soils, a Regosol and a Luvisol, representative of forest areas of southeast Spain. Heating temperature (200â500°C), vegetation type (Rosmarinus officinalis, Pinus halepensis and Brachypodium retusum), quantity of vegetation litter (control, low and high) and type of soil were selected as factors for assessing the WR induced by fire. The two soils exhibited markedly different WR responses after heating, the Regosol being much more susceptible than the Luvisol. Characteristics such as organic matter and clay content seem to determine the different WR responses to heating. We found that the type and quantity of vegetation litter also control the persistence of induced WR. In general, the order of increasing WR was Brachypodium < Pinus < Rosmarinus, and larger amounts of litter induced more WR. Maximum values of WR, most of them classified as severe (901â3600 s), were found in the range of 300â350°C, whereas beyond this temperature WR was destroyed. These results show that water repellency induced by combustion could be limited by environmental factors such as vegetation type and availability of litter, and that soil type and its characteristics also play a decisive role.
Abstract: Sewage sludges are increasingly used in soil amendment programmes, although not without risk since they contain, among other potential hazards, high concentrations of total coliform bacteria. In this paper we have studied the effect of irrigation on the survival of total coliforms in three semiarid degraded soils with different agricultural practices. Fresh sewage sludge was added at 50 g kg(-1) soil, and incubated in both the presence and absence of irrigation. The absence of irrigation led to a sharp decrease in the number of total coliforms in all soils, with the bacteria disappearing in 40 days. Irrigation produced a substantial initial increase in the number of coliforms in the three soils, although after 80 days there was none growing in any of the soils. The results showed that there were significant differences in the survival of coliform bacteria due to the presence or absence of irrigation.
Abstract: Information about the mineralisation rates and effects on soil microorganisms must be obtained prior to the rational use of organic wastes in agriculture or forestry. The objective of this work was to study the mineralisation of two manures derived from the solid phase of pig slurries and the effects on the soil microbial biomass of an agricultural soil. Samples of this soil were mixed at two different rates with two manures derived from the solid phase of pig slurry (composted, CSP, and non-composted, NSP), and then were incubated during 163 days. Carbon mineralised from manures was fitted to first-order kinetic model, and small differences were found between manures despite the composting of one of them. Approximately 45% of the C added was mineralised in the experimental period. The soil microbial biomass C (Cmic) was increased by the amendments according to the application rate. The sudden increases of the qCO2 in the treated samples were ephemeral. The most appreciable differences between these manures were those related with net N mineralisation, being greater in the NSP-treated samples. The application of the solid phase of pig slurries, composted or not, could be a feasible practice to enhance in a short-term the microbial biomass of agricultural soils. In order to avoid an excessive release of inorganic N, the use of composted materials is preferred
Abstract: Water deficit and soil degradation have become some of the major problems for crop production in semi-arid regions, as it is the South East of Spain. As a matter of fact, considerable productivity loss and risk of erosion have to be taken into account in these areas, especially those with an horticultural use (Davis, 1989). Utilization of sewage sludge in agriculture. Agricultural Progress 64, 72â80]. Horticultural soils are highly vulnerable and prone to erosion, as vegetables are generally fast-growing species under intensive exploitation regimes. High-rate chemical inputs contribute to horticultural soil degradation and have a dramatic effect on soil microbial population and nutrient balance whilst, at the same time, have a counter-effect on price competitiveness of the vegetables to be commercialized. In this paper we monitored variations in physical, chemical and biological properties of a cauliflower plot where four increasing quantities of compost were applied. We carried out a three-stage sampling schedule in order to check the effect of compost applications doses. We conclude that a 2 kg compost/m2 application had a positive effect on physical and biological properties of the soil and provides a supply of nutrients to grow cauliflowers on its surface under intensive exploitation regimes without loss in biomass yield.
Abstract: Abstract This paper deals with the environmental characterization of the âÂÂCollao de Candelaâ enclave (Alicante, SE Spain), which in the early 1980s reported strong mining activity mainly due to the extraction of marls. The subsequent abandonment of such quarries produces floods in depressed areas that are constituted as pools. These anthropogenic wetlands are the object of this research. In order to characterize the geometry of the studied wetlands a bathymetry was carried out. Bathymetric data are very important for water managers tasked with assessing wetlandsâ status. A chemical and mineralogical characterization has been carried out on the lithologies in the study area. A study was also conducted of the physical and chemical parameters of the waters contained in these pools during one hydrologic cycle. The climate of the zone, having elevated evapotranspiration measurements, favors a progressive concentration of salts in the pools consequence of runoff water washing, the evaporitic sediments as well as from elevated evaporation. The results obtained justify the environmental protection of these marl-gypsum mining quarries as potential wetlands.
Abstract: Abstract The necessity of eliminating debris from a granite quarry has awakened an interest in applications of by-products, called âÂÂmarginal aridsâÂÂ, in different fields, like construction and foundations for roadways, restoration, material for the manufacture of artificial rocks, and artesian products etc. Conclusions obtained from the results of tests carried out by X-ray diffraction of granite quarry by-products in Extremadura, Spain, submitted to different treatments, are established. Test pieces from two quarries are analyzed and compared generally and specifically, for commercial use. Finally, conclusions relating to essays in test pieces and mineral dynamics of marginal arid granite are exposed.
Abstract: Soil enzyme activities are useful indicators of soil quality as they are very sensitive to disturbance. Sample storage or pre-treatments could affect the results in these assays, which are normally determined in fresh samples, kept cold or frozen. The objectives of this study were to (i) evaluate the effect of air-drying or air-drying and rewetting on β-glucosidase, acid phosphatase and urease activities in soils from different locations, degradation status and sampling seasons, and (ii) assess if air-drying or air-drying and rewetting is an accurate sample storage and pre-treatment procedure for enzyme activities in soil quality evaluations under semiarid Mediterranean conditions. Our results showed that urease, phosphatase and β-glucosidase activities were hardly affected by air-drying of degraded and non-degraded soils from the two locations studied in all seasons. Short incubations (4, 8 and 12 d at 23 °C) of rewetted air-dried soil at 55% of water-holding capacity showed different patterns depending on the enzyme studied. Urease and β-glucosidase activities were relatively stable during incubation, with several significant (P<0.05) shifts up and down in some soils and samplings. However, acid phosphatase showed an increase in activity with incubation, of between 5% and 50% relative to air-dried samples. These increases followed no pattern and were unrelated to soil characteristics or sampling date. Hence, urease, phosphatase and β-glucosidase activities determined in air-dried soil samples seem to be representative of those obtained under field-moist conditions. In contrast, short incubations of rewetted soil samples can produce fluctuations in these enzyme activities, mainly of acid phosphatase, and estimations in these conditions are not so representative of field-moist soil values.
Abstract: Despite important advances in the understanding of biological soil crusts and their key role in ecosystem processes in arid and semi-arid environments, little is known about those factors driving the small-scale patterns of abundance and distribution of crust-forming lichens and mosses. We used constrained ordination techniques (RDAs) to test the hypothesis that the spatial patterning of lichens and mosses is related to surface and subsurface soil variables in two semi-arid gypsum environments of Spain. Our results show that the abundance of mosses and lichens forming biological soil crusts was related to a limited set of variables (cover of bare soil and litter, soil respiration, potassium content and aggregate stability). Moreover, they provide some insights into the importance of these variables as drivers of biological soil-crust composition and abundance in semi-arid gypsum environments.
Abstract: Improvement of organic matter content in Mediterranean soils is a main concern in soil management, especially in highly intensive agricultural areas and in degraded burned soils. Solid pig slurry is a good soil amendment, not only for its high organic matter content but also for the nutrient it can supply. The objective of this study was to estimate the influence of raw and composted application of a solid pig manure on the NPK content of two degraded soils. Two calcareous soils (Typic Xerofluvent, with highly intensive agricultural use, and Lithic Xerorthent, affected by forest fire) were incubated (aerobically, nonleached conditions, 87 days of incubation at 25°C; soil moisture content 60% of WHC), with two manures derived from the solid phase of pig slurry (composted [CSP] and noncomposted [NSP]). The manures were mixed with the soils at two rates, adding 7 and 14 g organic C kg-1 soil, respectively, in 300-g pots. The variations in N, P, and K contents in soils were investigated. Both manure amendments increased organic N in the soils. Mineralization of organic N was affected by the type of soil and the composting of manure. Moreover, significant interactions between manure and soil type were observed. Available P was increased by the amendments also, but large differences have been observed between soils. After manure amendment, a higher increase in available P occurred in the agricultural soil with respect to the burned soil. Both manure types caused a similar increase of available P, but efficiencies (increase in availability with respect to total P added) were greater for the composted manure. The increase in available K was related to its content in the manures, being greater for the noncomposted manure. As expected, an increase in application rate led to higher NPK contents. The use of the solid phase of pig slurry could be a successful practice for improvement of soil fertility, which in turn stimulates the rapid recovery of vegetation in burned soils.
Abstract: The substitution of clayey raw materials urban sewage sludge in the production of traditional ceramics could give place to a cost saving due to the utilisation of wastes as secondary raw material. At the same time, it can help to solve the environmental problems associated to such wastes. This research shows the results of the substitution of clay for sewage sludge in different proportions in a ceramic body. The sludge characterisation has been carried out by an analytical protocol. After that, the most suitable products were selected regarding to the chemical composition and the technological characterisation of the resulting ceramic material.
Abstract: The distribution of chemical forms of Cd, Ni, Cr, Co, Ag, Pb, Cu, Mn and Zn in eight contaminated soils from Spain was studied using a sequential extraction procedure that fractionates the metal into soluble-exchangeable, specifically sorbed-carbonate bound, oxidizable, reducible and residual forms. SEM and EDXA analysis was used to analyse the soil matrix to determine the distribution of heavy metals. The residual, reducible and carbonate-sorbed forms were dominant. Metals were generally dispersed throughout the soil matrix and could not be located by SEM-EDXA.
Abstract: 1. Theoretical and modelling studies highlight the importance of the spatial patterns of organisms for ecosystem functioning, stability and dynamics. However, there is little empirical evidence as to their importance as drivers of such ecosystem attributes.
2. We evaluated the relationships between different biological soil crust attributes (spatial pattern, cover and diversity) and ecosystem functioning in two semiarid areas differing in the developmental stage of these crusts.
3. We found a significant direct relationship between spatial pattern and both soil bulk density and respiration (surrogates of ecosystem infiltration and nutrient cycling, respectively) at one of our study sites. However, the strength of such a relationship was lower than that found between attributes such as cover and evenness and the same ecosystem functioning surrogates.
4. Our results represent, to our knowledge, some of the first empirical evidence linking the spatial pattern of a community and ecosystem functioning. They also suggest that the importance of spatial pattern as a driver of ecosystem functioning may depend on community attributes such as cover and diversity, and that its importance may be lower than that of these attributes.
Abstract: The aim of this work is to propose a methodology that helps to learn about the distribution of different types of solid compounds in atmospheric aerosol, collected in an industrial area located in a Mediterranean basin that produces mineral raw materials. The work is developed from TSP samples collected daily in an open area near a ceramic production facility with a High Volume TSP sampler. The sampler permits the collection of sufficient daily quantities of particulate sample for subsequent X-ray diffraction characterisation and quantification. The results have shown that atmospheric aerosol in the area are dominated by particles coming from combustion processes, mainly vehicular traffic, and dust emissions originating when raw materials are transferred and treated. Combustion particles present a seasonal evolution. Mineral particles are mainly dependent upon weekly industrial activity and their contents suffer high increases during periods of atmospheric particle accumulation which are produced when certain meteorological conditions exist. Data have also shown an approximation of the particle distribution in aerosol from different source origins (vehicular traffic, dust emissions, secondary formation, marine aerosols). During days with intermediate pollution levels (which suppose 60% of the total) combustion particles compromise around 55 to 60% of the TSP while mineral particles coming from industrial dust emissions make up 20% of the TSP. In time intervals of atmospheric particulate accumulation these particle levels in the air can reach the legislated guideline values. During these episodes, mineral contents coming mainly from dust emissions compromise more than the 50% of the aerosol.
Abstract: The objective of this work is to assess the concentrations of three factions of air particles (settable particles, TSP and PM10) and the levels of several toxic elements in a clay atomisation industry through aerosol sampling at several points inside an industrial plant. Mechanical activities, which produce diffuse emissions, are the main process of discharge of particles in both indoor and outdoor workplace environments in the atomisation plant. The levels of As, Cd, Pb, Zn, Ba and Ni increase in the zones with higher concentrations of particles and lower ventilation. The concentrations of As and F are not influenced by the recycling processes. The levels of Cd and Pb do not show great enrichment in air particles collected inside the atomisation plant although the content of both elements is associated with ceramic muck recycling. Finally, the content of B in waste water is mainly transferred in gaseous phase to the atmosphere during the process of drying by atomisation.
Abstract: Total suspended particulate samples (TSP) were collected and concentrations measured during seventeen months in the vicinity of a ceramic industrial area. A method of fractionating was applied to the samples in order to obtain two fractions corresponding to mineral particulate coming from dust emissions (Upper-F fraction) and to amorphous matter (carbon plus small amounts of S, Ca, Fe, etc) coming mainly from traffic and other combustion processes. Also for TSP samples several element concentrations were measured following two previous treatments: extraction of elements mainly associated with the soluble fraction of the samples (B, Fe, P, As, NO 2-, NH 4+, Cl -, F) and acid digestion for trace metals and elements mainly associated with the non-soluble fractions of the samples (Fe, As, Cd, Ni, Pb, Zn Ca). Seasonal differences and the influence of meteorological parameters (temperature, relative humidity, pressure and wind conditions) on the air pollution levels, particles as well as ions, were studied. Results show different seasonal and weekly evolution for mineral and amorphous carbonaceous particles because of the different origins in dust emissions or combustion processes respectively, and the different physical properties such as size grain. Of the ions analyzed Fe, Ca and Zn were clearly associated to mineral phases and consequently related to dust emissions, and NO 2-, NH4+, P, Cl - were related to amorphous matter coming from combustion. Ni and Cd show lower levels than those reported as guideline values and the source is mainly related to the enrichment of these elements in clay materials. B and As content result in elevated concentrations, with the tendency to increase during cold months. The emission of these elements was associated with vaporization or volatilization during high temperature ceramic processes. The original gaseous state is influenced by temperature. In the winter the content for B and As is higher due to enhanced condensation of gas-phase boron onto particles, while in the summer the increase of air temperature results in elevated evaporation.
Abstract: Salinity is a highly important problem in arid and semi-arid regions. Consequently, the analysis of soil salinity plays a crucial role in environmental sciences. Environmental variables show spatial variability and statistical tools able to analyze and describe the spatial dependence and quantify the scale and intensity of the spatial variation are needed. Moreover, the spatial prediction has special importance for agricultural transformation of the land or for environmental restoration (selection of the most appropriate species adapted to soil salinity). In this paper we propose a methodological framework based on geostatistics to model the spatial dynamics of soil salinity measurements to further analyze the case of a region in southeastern Spain.
Abstract: Soil hydrophobicity is known to enhance runoff responses to rainstorms and to increase soil aggregate stability (AS). It has been widely reported for acidic soils particularly under burnt, but also unburnt pine forests following dry periods. Few studies have reported hydrophobicity from alkaline soils, but they have not established whether hydrophobicity also occurs in burnt or unburnt pine forests on alkaline soil. This study examines the wettability and stability of air-dry aggregates and their size fractions (<0.25, 0.25â0.5, 0.5â1 and 1â2 mm) taken from surface layers (0â2.5 and 2.5â5 cm depth) of alkaline, calcareous loamy soils. Four sites in southeastern Spain were sampled with comparable vegetation (>30-year-old Aleppo pine {Pinus halepensis} and associated shrub community), geology (limestone), soil type (Lithic Xerorthents), slope angle and aspect (5â8°SW). Included were three sites (A, B, C) burned, respectively, in 1998, 1999 and 2000, and one unburnt for >30 years (D). Hydrophobicity was detected in samples from all sites. Both spatial frequency and persistence of hydrophobicity (Water Drop Penetration Times (WDPT) ranged from 10 to 600 s), however, was lower than reported from studies of acidic soils under pine. This might be associated with a lower susceptibility of alkaline soils to hydrophobicity development and/or the comparatively low biomass production in the region. Probably because it had been most recently affected by severe fire, spatial frequency of hydrophobicity was higher at site B (53% of samples), compared to A, C and D (6%, 33% and 10% of samples, respectively). In contrast to some previous studies, the finest size fraction of the samples consistently had the highest degree of hydrophobicity. Degree of hydrophobicity was positively correlated with organic matter (OM) content (r=0.714). It is speculated that fine, interstitial hydrophobic organic matter accumulating in the finest sieve fraction contributes to this enhanced hydrophobicity. As shown in previous studies on acidic soils, aggregate stability increased with hydrophobicity (r=0.897 in the fraction 0.25â2 mm) for the samples investigated here. This elevated stability occurs despite an already relatively high level of aggregate stability amongst all samples investigated. Hydrophobicity observed at the study sites was not spatially contiguous and it may therefore enhance overland flow and slope wash over only short distances for most, except the very high intensity rainstorms that occur in the region. The increased stability of hydrophobic soil aggregates against slaking, however, may counter an otherwise enhanced susceptibility to erosion.
Abstract: The percentage calculation of crystalline phases in atmospheric particulate matter samples by means of an adiabatic approach of the matrix-flushing method with preferred preparations that avoids preferential orientations, should never be interpreted as absolute values. On the contrary, it should be seen as an indicator of the significant differences between each and every analyzed sample. Factors such as the application of constants, which are only useful for preparations of polycrystalline samples free of preferential orientation, and/or like the deficient resolution shown by the diffraction diagrams for certain phyllosilicate phases, bring a high degree of uncertainty to these percentage calculations. An alternative method of crystalline and amorphous phase quantification is presented below. Once the majority phases in the samples were identified, appropriate pure phases corresponding to each of them were selected. Then, the corresponding calibration curves were built using corundum (number 676 NIST) as a reference pattern phase. After validating the obtained calibration curves, the constants corresponding to each phase and selected spacing were calculated. The ALJOR method has been used for the quantification of five samples.
Abstract: Contaminating industrial emissions produced by the ceramics industries (including frit and enamel production) can be divided into dust emissions and emissions produced in high temperature activities. Processes of accumulation and precipitation on the substratum, of compounds enriched in certain elements used in this type of industry can occur. The objective of the present work was to identify the contribution of the emissions of the ceramics industries to the atmospheric particulate that is susceptible to depositing on vegetation and accumulating in the substratum. Samples obtained from high volume collectors were studied. Two zones were considered: zone A, a high volume collector located in the municipalities adjacent to the companies that were the object of the study; and zone B, a high volume collector further away from the said companies and adjacent to a power station and a refinery. The analysis techniques were X-ray diffraction, scanning electron microscopy (SEM), and ICP-MS. The results obtained by means of the X-ray diffraction technique showed a high percentage of clays in the samples, minerals used as raw materials (K-Ba feldspar, zircon silicate), indications of high temperature phases, as well as a background noise characteristic of material of low crystallinity. The SEM analysis confirmed the presence of vitreous particles, which are crystalline phases at high temperature typical of the production of a large variety of frits. The results obtained in the chemical analysis demonstrate that (a) the influence of the frits and enamel production on the high concentrations of Zr, Cu and Ce obtained in zone type A compared with zone B; (b) the affect of clays used as raw materials in the ceramics industry can be demonstrated by the high concentrations of Fe, Al and Mg. The weekly evolution showed two series of elements, a characteristic group of dust emissions and another group of tracers from high temperature processes.
Abstract: The reclamation of burned soils in Mediterranean environments is of paramount importance in order to increase the levels of soil protection and minimise erosion and soil loss. The changes produced in the content of total organic carbon (TOC), N (Kjeldahl) and available P, K, Ca and Mg by the addition of different doses of a municipal solid waste compost to a burned soil were evaluated during one year. The effect of organic amendment on the improvement in the vegetation cover after one year was also evaluated. The organic amendment, particularly at a high dose, increased the TOC and N-Kjeldahl content of the soil in a closely related way. The levels of available K in soil were also enhanced by the organic amendment. Although the effects on all three parameters tended to decrease with time, their values in the amended soils were higher than in the control soil, which clearly indicates the improvement in the chemical quality of the soil brought about by the organic amendment. The available P content did not seem to be influenced by organic treatment, while available Mg levels were higher than in the control during the first 4 months following organic amendment. The application of compost to the burned soil improved its fertility and favoured rapid vegetal recovery, thus minimising the risk of soil erosion.
Abstract: The incidence of power station emissions in the composition of the atmospheric aerosols in an urban-industrial area is presented in this study. The Iberdrola (Spanish electrical company) thermoelectric power station is located at Castellon's industrial estate along the Spanish Mediterranean coast. Due to the fact that there are other polluting industries in this region, the present study is also helpful to investigate potential tracers to discriminate the origin and source of particular pollution events. The analysis of air particulate samples, collected on cellulose membrane filters, was carried out by means of the following instrumentation: (1) mineralogical analysis by X-ray diffraction (XRD), (2) morphological study by scanning electron microscopy (SEM/EDX), and (3) chemical analysis by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS), to carry out quantitative chemical analyses of both major and trace elements. This analysis has allowed the authors to find marker elements, V and Zn, for the power station emissions.
Abstract: Mineralogical transformations caused by firing, of five different compositions used in the formulation of ceramic pastes have been studied. Test samples have been prepared by extrusion and fired in the range of 900â1150°C. Analysis of the fired samples was carried out by optical microscopy. The presence of enstatite, gehlenite, hercynite and mullite and abundant vitreous phase showed neomineralization. A fluid texture was present in all the samples and phenocrysts occurred in the partially microcrystalline matrix. In this way, the ceramic ware was analogous to porhyritic type rocks, with quartz phenocrystals and a typical undulating liquidation, opaque minerals such as hematites and crystalloblastic quartz structures on grains of orthoclase. The samples with low carbonate contents were composed of bulky particles, predominantly of quartz and hematites, which are agglomerated in a vitreous matrix.
Abstract: The agricultural quality of a calcareous soil amended with organic wastes was assessed during a cultivation season. Extraction techniques were used to determine the availability of a range of plant nutrients. Soil was fertilised with two organic residues, sewage sludge and epicarp-mesocarp of almonds. These wastes clearly affected soil composition. Sewage sludge influenced the soil content of N, P, Fe, Cu and Zn. Almond residue mainly modified extractable K. Both residues changed the soil salinity (measured as electrical conductivity), and soil organic matter. Yield was also determined in the tomato plants cultivated. Sewage sludge improved yield; no difference was observed between the other fertiliser treatments.
Abstract: Three experiments were carried out using horticultural plants (artichoke, cabbage and potato) in southeast Spain (Alicante) for two cropping seasons. A reduced mineral fertilisation treatment (â N, less than 300 kg N haâ1) was compared with the traditional input of nitrogen (+N, around 500 kg N haâ1) to evaluate the losses of mineral forms in the soil profile, quantity of plant nitrogen and yield. Three plots were used. Nitrate, ammonium and organic N were measured in the soil profile at four depths (0â30, 30â60, 60â90 and 90â120 cm), and amounts of plant nitrogen in the aerial and edible parts of the plant evaluated, together with the marketable yields in each season. Nitrogen losses were reduced, especially in the second season, but plant nitrogen and yield were not significantly affected
Abstract: Tomato plants were grown in a calcareous soil supplemented with two organic wastes (sewage sludge and epicarp-mesocarp of the almond tree fruit). They were irrigated at three levels of salinity caused by the addition of sodium chloride. N, P, K, Na, Ca and Mg were determined in the soil and tomato fruits. The treatments had a significant incidence on mineral content in fruit and soil.
