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Tidal marshes store large amounts of organic carbon in their soils. Field data quantifying soil organic carbon (SOC) stocks provide an important resource for researchers, natural resource managers, and policy-makers working towards the protection, restoration, and valuation of these ecosystems. We collated a global dataset of tidal marsh soil organic carbon (MarSOC) from 99 studies that includes location, soil depth, site name, dry bulk density, SOC, and/or soil organic matter (SOM). The MarSOC dataset includes 17,454 data points from 2,329 unique locations, and 29 countries. We generated a general transfer function for the conversion of SOM to SOC. Using this data we estimated a median (± median absolute deviation) value of 79.2 ± 38.1 Mg SOC ha−1 in the top 30 cm and 231 ± 134 Mg SOC ha−1 in the top 1 m of tidal marsh soils globally. This data can serve as a basis for future work, and may contribute to incorporation of tidal marsh ecosystems into climate change mitigation and adaptation strategies and policies.

Afforestation is a good strategy for climate change mitigation through increasing carbon stocks. This study determined changes in soil respiration (SR) brought about by the afforestation of high quality agricultural land in a temperate-humid region (Galicia, NW Spain), identified the variables that explain the observed changes and determined the main factors regulating SR temporal variation. Paired plots of fertile soils (cropped vs. afforested plots) were established in two similar areas (Pontevea and Laraño) where afforestation with Populus x euroamericana (Dode) Guinier was carried out in the same year. Different management practices and crop rotations were used (maize–pasture, Laraño and maize–fallow, Pontevea). The SR was measured in situ with a CO2 static chamber every 15 days (every month in winter) for 16 months; soil temperature (Ts) and soil moisture content (W) were also measured. In both areas, significant differences (p < 0.05) in SR between paired plots were related to soil organic C content and SR was mainly influenced by Ts, except during the summer period where SR fluctuations were accompanied by W fluctuations. These findings show that growing pasture crops on high quality land can prevent the loss of soil N and C and probably improve the greenhouse gas balance in the system.

Ionic liquids are playing an increasingly relevant role in green chemistry due to one of their main important characteristic, their negligible vapour pressure, which means they are non-contaminant (o harmless) to the atmosphere. Nevertheless, they could be toxic for terrestrial ecosystems and therefore research to assess its toxicity to aquatic and terrestrial environments should be performed to assess whether they are as innocuous as sometimes assumed. The 1,3 dimethylimidazolium dimethylphospate, [C1C1Im][DMP], is an imidazolium ionic liquid with potential use in several industrial applications. Thus estimating the toxicity of this compound to these terrestrial ecosystems is of priority. In this study, we investigated the impact of different amounts of 1,3-dimethylimidazolium dime thyl phosphate ([C1C1Im][DMP]) on soil microbial activity by using two different methods: isothermal microcalorimetry and the classical method for meas uring basal soil respiration. The aims of the study were to estimate the toxicity of this compound to soil microorganisms, to assess whether both methods were equally sensitive to estimate the impact of this ionic liquid on soil microbial activity and to combine the information obtained by both methods to obtain a more insightful picture of the impact of this compound on soil microbial activity.

Afforestation of marginal land has been recommended by the Intergovernmental Panel on Climate Change (IPCC) as a means of enhancing the capacity of soil to act as a carbon (C) sink. However, the success of this practice is variable and depends on many factors, including the type of land management used. In this study, we quantified and compared the C stocks in two highly productive agricultural soils afforested with poplar 10 years before the study and in adjacent soils still used for agricultural purposes. One of the agricultural soils was sown with grass and maize in a crop rotation system and the other was alternately sown with maize (6 months) and left fallow (6 months). In all soils, we estimated the C pools associated with the live biomass (including the C extracted by harvesting in the cropped soils in the 10 years since afforestation), dead biomass, amount of fertiliser added (quantifying all inputs of C added as fertiliser in the cropped soils since the start of afforestation) and the soil organic matter (0–100 cm), to enable estimation of the total C stocks in the ecosystem. Afforestation had different effects on the various C pools. Thus, although afforestation enhanced the C sink capacity of the ecosystem when carried out on agricultural land, the degree to which this occurred varied according to previous land use. The increase in C stocks that occurred from afforestation was lower in the plots employing maize-grass rotation, compared to those with maize-fallow rotation. The ecosystem C balance was quite similar in both afforested plots (247.4 and 233.0 Mg C ha−1), while it was quite different in the cultivated plots (182.3 Mg C ha−1 in Laraño; 73.9 Mg C ha−1 in A Barca). Although at both sites the C balance was higher in the afforested plot than in the cultivated plot, the differences were much smaller in Laraño (65.1 Mg C ha−1 higher in the forested plot than in the cultivated plot) than in A Barca (159.1 Mg C ha−1 higher in the forested plot than in t

Salix viminalis L. is a species with high capacity for micropropagation and acclimation and could therefore be used to evaluate emergent techniques in the field of plant propagation. The aims of this study were to propagate willow in liquid medium with a continuous immersion system, to explore the application of photoautotrophic conditions and to investigate the adaptation of willow plantlets to different soils that could be used as alternatives to commercial peat. For proliferation, we used 3% sucrose or sugar-free medium, and as substrates, we used commercial peat, a soil from an oak forest with high organic matter content and a crop soil with low organic matter content. The effect of sugar supplementation during proliferation and the soil characteristics during acclimation and growth were evaluated on the basis of aerial and root growth and the hydrolytic and dehydrogenase enzymatic activities of the soils. The results indicate that under photoautotrophic conditions, the supplementation of sucrose during micropropagation did not affect the subsequent growth of the plantlets. All plants acclimated without loss, but the type of soil influenced the height and vigor. Plants produced the highest shoots in peat, whereas the most root development occurred in crop soil. Soil enzyme activities were more influenced by the type of soil than by the presence of plants.

Afforestation is a good strategy for climate change mitigation through increasing carbon stocks. This study determined changes in soil respiration (SR) brought about by the afforestation of high quality agricultural land in a temperate-humid region (Galicia, NW Spain), identified the variables that explain the observed changes and determined the main factors regulating SR temporal variation. Paired plots of fertile soils (cropped vs. afforested plots) were established in two similar areas (Pontevea and Laraño) where afforestation with Populus x euroamericana (Dode) Guinier was carried out in the same year. Different management practices and crop rotations were used (maize–pasture, Laraño and maize–fallow, Pontevea). The SR was measured in situ with a CO2 static chamber every 15 days (every month in winter) for 16 months; soil temperature (Ts) and soil moisture content (W) were also measured. In both areas, significant differences (p < 0.05) in SR between paired plots were related to soil organic C content and SR was mainly influenced by Ts, except during the summer period where SR fluctuations were accompanied by W fluctuations. These findings show that growing pasture crops on high quality land can prevent the loss of soil N and C and probably improve the greenhouse gas balance in the system.

Interest in the possible use of EAN in electronic devices has increased in recent years. EAN can be used directly as an electrolyte, but its application could potentially be optimized by mixing with a metal salt such as Al(NO3)3. Although ionic liquids (ILs) have been considered to cause little harm because they are non-volatile, they can have toxic effects on the terrestrial environment. In this study, the impact on soil basal respiration of EAN alone, a mixture of EAN and Al(NO3)3, and Al(NO3)3 alone was investigated using two soils with different organic matter contents. The Al(NO3)3 did not affect soil respiration in either soil, while EAN, either alone or mixed with Al(NO3)3 affected both soils.

Farmyard manure, an amendment traditionally used for improving the fertility of sandy soils in arid climates, is becoming scarce and expensive. Its shortage makes it necessary to evaluate, at field scale, the suitability and medium-term performance of other cheap, highly available substitutes. A field trial was established to analyze the effects of a single application of three organic residues on barley yield and nutrient uptake and selected soil properties after two consecutive harvests. Municipal solid waste compost (MSWC), sewage sludge compost (SSC) and farmyard manure (FYM) were tested at rates of 0, 20, 40 and 60 t ha−1. Adding all three organic amendments increased organic matter, cation exchange capacity and available P, Ca, Mg and K in the soil, the grain yield (up to 51%), and the barley plants’ nutrient contents. After the second harvest, a positive residual effect of the amendment was observed in plant yield (up to 77%) and nutrient contents. MSWC and SSC induced slight increases on the extractable fractions (BCR protocol) of Co, Cu and Ni, relative to the unamended soil. The results demonstrate the positive immediate and residual effect of the amendments evaluated as fertilizers for agricultural purposes.

Ionic liquids (IL) represent an alternative to organic solvents in processes of synthesis compounds and in separation technologies due their tuneable physicochemical properties as they can be synthesised by choosing from an enormous amount of cations and anions or even by changes in the alkyl chains of these ions. One of the key properties of these compounds is their negligible vapour pressure, due to which they are non-contaminant to the atmosphere and play an increasingly relevant role in green chemistry. Nevertheless, before their use can be generalised, toxicity studies must be performed as they could be toxic for terrestrial ecosystems. However, studies of the effects on soil and vegetation, media that can be reached by these liquids as a result of accidental spills, are scarce so far. The 1,3 dimethylimidazolium dimethylphospate, [C1C1Im][DMP], is an imidazolium ionic liquid with potential use in several industrial applications, as for example increasing the rate of cellulose hydrolysis by cellulase enzyme in the bleaching process in paper and pulp industry. Thus, once its use will be widespread, the probability that reaches terrestrial ecosystems will be high and therefore estimating the toxicity of this compound to these systems is of priority. The main goals of this study were i) to estimate the toxicity of [C1C1Im][DMP] to the soil by analysing its effect on soil microbial activity, ii) to test the sensitivity of two procedures (microcalorimetry and the classical method of soil basal respiration determination) to estimate microbial activity in IL-polluted soils, and iii) to compare and combine the information provided by both procedures to obtain a more insightful picture of the impact of this compound on soil microbial activity. The microcalorimetry technique is based on the analysis of the heat released by soil microbiota, activated with a solution of glucose, against time. The second methodology (soil basal respiration) is the classic measurement of the

Biocrusts are an essential soil surface cover at drylands where ecosystems are especially fragile to soil degradationprocesses due to climatic peculiarities. In the present work, (micro)biological and physicochemical properties indic-ative of soil functionality were studied in two different biocrust types dominated byDipolschistes diacapsisandLepraria isidiataand in underlying soil at two different depths (SL1, soil layer right below the biocrusts, and SL2,soil layer underlying SL1) at the Tabernas desert (southeast Spain). The influence of climatic factors (rainfall andtemperature) and general soilproperties on the (micro)biological properties were also analyzed in different envi-ronmental (climatic) conditions over a period of two years. PERMANOVA analyses showed significant statisticaldifferences (Pseudo-F = 63.9; P (perm) = 0.001) among biocrust and soil layers. Throughout the study period, en-zyme activities involved in C, N, and P cycles; microbial biomass-C; basal respiration; and several properties directlyrelated to ecosystem productivity (total organic carbon, total nitrogen, concentration of ammonium and nitrate)were higher in both biocrust types than in the underlying soil layers, showing that biocrusts improved soil functionsrelated to nutrient cycling. These properties progressively diminished in successive soil layers under the biocrusts(biocrusts > SL1 > SL2). Biocrusts showed greater similarity to each other and to SL1 than to SL2 in (micro)biologicalproperties. A distance-based linear model analysis showed that total organic carbon, rainfall, pH, mineralized N-NH4+, and total nitrogen were the most important variables for predicting (micro)biological soil properties inbiocrusts. Different biochemical behavior between the biocrusts and successive underlying soil layers has beenfound in wet periods. After rainfall periods, the biocrusts showed important peaks in basal soil respiration and in en-zyme activities involved in C and P cycles. Nevertheless

Although ionic liquids (ILs) do not contaminate the atmosphere (because of their low vapour pressure), they may have toxic effects in aquatic and terrestrial environments. Therefore, before ILs can be widely used for different applications, their toxicity must be tested in different environments. The IL ethylammonium nitrate (EAN) is of interest in electrochemical applications, and research is currently underway to investigate the electrochemical activity of mixtures of this compound with inorganic salts. In this study, we investigated the impacts of different amounts of pure EAN and of mixtures of EAN and lithium salt on basal soil respiration in two soils differing in organic matter content.

The ecotoxicity of a mixture of the ionic liquid ethylammonium nitrate (EAN) and aluminum nitrate salt (Al(NO3)3) as well as the corresponding to pure components was studied in this work. This mixture has singular interest as electrolyte in electrochemical applications and data about the effects of mixture and components on the environment can hardly be found in literature. Changes on the bioluminescence of the Aliivibrio fischeri (Beijerinck) Urbanczyk bacteria through Microtox®test and on microbial activity, measured by microcalorimetry, of two soils with different organic matter content, when exposed to solutions of different concentrations of these compounds, were analyzed.

Soils from arid and semi-arid ecosystems are generally very low in organic matter content, poor in nutrients and typically with sandy texture. The application of different organic amendments has been proposed as an adequate approach to improve the quality of these soils for their use in agriculture. The use of organic wastes of different origins (agricultural, industrial, urban, etc.) as soil amendments has a dual goal: i) improving soil fertility and quality, ii) reducing the environmental problem that poses the disposal of these residues. However, despite of the beneficial effects of these residues, undesirable changes may also occur in agricultural soils after their addition. For example, the presence of various pollutants of anthropogenic origin in organic wastes may cause adverse effects on soil microbiota. Generally, the arid and semi-arid soils of Tunisia are well characterised. However, the use of organic amendments to improve the quality of these soils has been scarcely investigated. Soil biochemical properties, and specifically soil enzyme activities, have been often used to investigate the impact of different amendments on soil quality, because they are highly sensitive to human or environmental perturbations. In this work, the results of a field trial established for investigating the effectiveness of three organic residues (composted municipal solid waste, composted sewage sludge and farmyard manure) to improve the quality of one agricultural soil from Tunisia are reported. The soil had a sandy texture, alkaline pH (pH 8.3) and was very poor in organic matter (0.21 and 0.03% of total C and N, respectively). Each of the organic residues was applied in triplicate at three different doses in nine sub-plots randomly distributed; three untreated sub-plots were also established for comparison. One, 6 and 18 months after the soil amendments, surface (0-20 cm) soil samples were collected from all the treated and untreated subplots. The soil samples were analyse