Biochar-Compost blends modulate trace element and nutrient dynamics in rooftop farming systems under Mediterranean conditions.

The rising interest in Rooftop Agriculture (RA) has stemmed a demand for sustainable, lightweight alternatives to peat as plant growing media. Co-composting organic waste with biochar could represent a solution with reduced environmental impact. However, knowledge gaps remain regarding the food safety and environmental performance of these materials.

Global impoverishment of natural vegetation revealed by dark diversity.

Anthropogenic biodiversity decline threatens the functioning of ecosystems and the many benefits they provide to humanity. As well as causing species losses in directly affected locations, human influence might also reduce biodiversity in relatively unmodified vegetation if far-reaching anthropogenic effects trigger local extinctions and hinder recolonization. Here we show that local plant diversity is globally negatively related to the level of anthropogenic activity in the surrounding region.

Engineered Mg-modified biochar-based sorbent for arsenic separation and pre-concentration.

The utilization of biochar as a relatively efficient sorbent or stationary phase for the separation and preconcentration of a wide range of analytes represents an innovative approach in current sample pretreatment methods. Appropriate pre- and post-pyrolysis modification of the input precursor and pyrolysis product, respectively, allows targeted design of the physicochemical properties and sorption characteristics of the resulting sorbent. The present work deals with the preparation of pyrolysis materials based on unmodified cattail leaf biomass (BC) and its Mg-modified analogue (MgBC) by a slow pyrolysis process at 500 °C and a residence time of 1 h in a pyrolysis reactor.

Unforeseen plant phenotypic diversity in a dry and grazed world.

Earth harbours an extraordinary plant phenotypic diversity that is at risk from ongoing global changes. However, it remains unknown how increasing aridity and livestock grazing pressure-two major drivers of global change-shape the trait covariation that underlies plant phenotypic diversity. Here we assessed how covariation among 20 chemical and morphological traits responds to aridity and grazing pressure within global drylands.

Metallic micronutrients are associated with the structure and function of the soil microbiome.

The relationship between metallic micronutrients and soil microorganisms, and thereby soil functioning, has been little explored. Here, we investigate the relationship between metallic micronutrients (Fe, Mn, Cu, Zn, Mo and Ni) and the abundance, diversity and function of soil microbiomes. In a survey across 180 sites in China, covering a wide range of soil conditions the structure and function of the soil microbiome are highly correlated with metallic micronutrients, especially Fe, followed by Mn, Cu and Zn.

The potential of arbuscular mycorrhizal fungi to enhance metallic micronutrient uptake and mitigate food contamination in agriculture: prospects and challenges.

Optimizing agroecosystems and crops for micronutrient uptake while reducing issues with inorganic contaminants (metal(loid)s) is a challenging task. One promising approach is to use arbuscular mycorrhizal fungi (AMF) and investigate the physiological, molecular and epigenetic changes that occur in their presence and that lead to changes in plant metal(loid) concentration (biofortification of micronutrients or mitigation of contaminants). Moreover, it is important to understand these mechanisms in the context of the soil microbiome, particularly those interactions of AMF with other soil microbes that can further shape crop nutrition.

Increasing the number of stressors reduces soil ecosystem services worldwide.

Increasing the number of environmental stressors could decrease ecosystem functioning in soils. Yet this relationship has never been globally assessed outside laboratory experiments. Here, using two independent global standardized field surveys, and a range of natural and human factors, we test the relationship between the number of environmental stressors exceeding different critical thresholds and the maintenance of multiple ecosystem services across biomes.

Soil contamination in nearby natural areas mirrors that in urban greenspaces worldwide.

Soil contamination is one of the main threats to ecosystem health and sustainability. Yet little is known about the extent to which soil contaminants differ between urban greenspaces and natural ecosystems. Here we show that urban greenspaces and adjacent natural areas (i.

Grazing and ecosystem service delivery in global drylands.

Grazing represents the most extensive use of land worldwide. Yet its impacts on ecosystem services remain uncertain because pervasive interactions between grazing pressure, climate, soil properties, and biodiversity may occur but have never been addressed simultaneously. Using a standardized survey at 98 sites across six continents, we show that interactions between grazing pressure, climate, soil, and biodiversity are critical to explain the delivery of fundamental ecosystem services across drylands worldwide.

Review on the interactions of arsenic, iron (oxy)(hydr)oxides, and dissolved organic matter in soils, sediments, and groundwater in a ternary system.

High concentrations of arsenic (As) in groundwater threaten the environment and public health. Geogenically, groundwater As contamination predominantly occurs via its mobilization from underground As-rich sediments. In an aquatic ecosystem, As is typically driven by several underlying processes, such as redox transitions, microbially driven reduction of iron (Fe) oxide minerals, and release of associated As.

Synergistic effects of biochar and biostimulants on nutrient and toxic element uptake by pepper in contaminated soils.

Background: Nowadays a significant amount of land contaminated with toxic elements is being used for agriculture, posing a serious risk of crop contamination and toxicity. Several methodologies are being used to remediate soil contamination, including the use of amendments such as biochar. This work evaluated the effects of biochar combined with different fertirrigations (water, a conventional fertilizer solution, or a fertilizer solution with a commercial biostimulant derived from leonardite) on the availability of toxic elements and nutrients for pepper cultivated in a soil contaminated with As, Cd, Pb, and Zn.

(Im)mobilization of arsenic, chromium, and nickel in soils via biochar: A meta-analysis.

Biochar is a promising immobilizing agent of trace elements (TEs) in contaminated soils. However, several contradictory results have been reported regarding the potential of biochar to immobilize arsenic (As), chromium (Cr), and nickel (Ni) in contaminated soils. We conducted a meta-analysis on the published papers since 2006 until 2019 to examine the effects of biochar on the chemical (im)mobilization of As, Cr, and Ni in contaminated soils and to elucidate the major factors that control their interactions with biochar in soil.

Soil element coupling is driven by ecological context and atomic mass.

The biogeochemical cycling of multiple soil elements is fundamental for life on Earth. Here, we conducted a global field survey across 16 chronosequences from contrasting biomes with soil ages ranging from centuries to millions of years. For this, we collected and analysed 435 topsoil samples (0-10 cm) from 87 locations.

Biocrusts buffer against the accumulation of soil metallic nutrients induced by warming and rainfall reduction.

The availability of metallic nutrients in dryland soils, many of which are essential for the metabolism of soil organisms and vascular plants, may be altered due to climate change-driven increases in aridity. Biocrusts, soil surface communities dominated by lichens, bryophytes and cyanobacteria, are ecosystem engineers known to exert critical functions in dryland ecosystems. However, their role in regulating metallic nutrient availability under climate change is uncertain.

Mobility of arsenic, chromium and copper arising from soil application of stabilised aggregates made from contaminated wood ash.

Stabilized cementitious aggregates AG were produced from wood ashes containing ∼10,000 mg kg As, Cr and Cu, then amended to two agricultural pasture soils. Metal(loid) leaching (column tests), mobility (pore water extracts) and uptake to ryegrass was determined, comparing raw ashes with aggregates. Risk modeling was applied to selected data to inform wider discussion of the experimental results.

Localized Intensification of Arsenic Release within the Emergent Rice Rhizosphere.

Behavior of trace elements in flooded/lowland rice soils is controlled by root-zone iron oxidation. Insoluble iron species bind/capture toxic elements, i.e.

Engineered Pyrogenic Materials as Tools to Affect Arsenic Mobility in Old Mine Site Soil of Mediterranean Region.

The application of pyrogenic materials in immobilization processes of metalloids represents a burning issue in environmental and waste applications and management. The main objective of this study was to characterize the effect of biomass pretreatment by Cu, Fe and Mg blending and pyrolysis temperature on As sorption efficiency as a model of anionic metalloids from model solutions and As immobilization in old mine soil by pyrogenic materials. The physico-chemical characterization of engineered materials produced in slow pyrolysis process at 400 and 700°C from metal-blended hard wood chips (30% w/w) showed increasing of surface areas (1.

Aided phytostabilisation over two years using iron sulphate and organic amendments: Effects on soil quality and rye production.

An outdoor macrocosm experiment using Fe-based and organic amendments over 2 years was set up to evaluate the effectiveness of aided-phytostabilisation. For that, a soil contaminated with As- and Cu-rich waste material (∼13000 mg As kg and ∼500 mg Cu kg) was treated with combinations of iron sulphate (Fe) with lime, paper mill sludge (PS), holm-oak biochar (BC), olive mill waste compost (OMWC) or green waste compost (GWC). Rye (Secale cereale L.

Complementary assessment of As, Cu and Zn environmental availability in a stabilised contaminated soil using large-bore column leaching, automatic microcolumn extraction and DGT analysis.

Soil pollution with trace elements is a concerning issue worldwide. Monitoring of soil pollution and remediation protocols need still from valid complementary analytical approaches able to detect changes in speciation and lability of metals in soils (e.g.

Aridity and reduced soil micronutrient availability in global drylands.

Drylands cover more than 40% of terrestrial surface, and their global extent and socio-ecological importance will increase in the future due to the forecasted increases in aridity driven by climate change. Despite the essential role of metallic micronutrients in life chemistry and ecosystem functioning, it is virtually unknown how their bioavailability changes along aridity gradients at the global scale. Here we analysed soil total and available Cu, Fe, Mn, and Zn in 143 drylands from all continents, except Antarctica, covering a broad range of aridity and soil conditions.

Designing biochar properties through the blending of biomass feedstock with metals: Impact on oxyanions adsorption behavior.

Metal-blending of biomass prior to pyrolysis is investigated in this work as a tool to modify biochar physico-chemical properties and its behavior as adsorbent. Six different compounds were used for metal-blending: AlCl, Cu(OH), FeSO, KCl, MgCl and Mg(OH). Pyrolysis experiments were performed at 400 and 700 °C and the characterization of biochar properties included: elemental composition, thermal stability, surface area and pore size distribution, Zeta potential, redox potential, chemical structure (with nuclear magnetic resonance) and adsorption behavior of arsenate, phosphate and nitrate.

The effect of biochar amendments on phenanthrene sorption, desorption and mineralisation in different soils.

The contamination of soils and waters with organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), affect a large number of sites worldwide that need remediation. In this context soils amendments can be used to immobilise PAHs while maintaining soil functioning, with biochar being a promising amendment. In this experiment, phenantrene (Phe) was used as a frequent PAH contaminating soils and we studied the effect of three biochars at 1% applications to three different substrates, two agricultural topsoils and pure sand.

Aided phytostabilisation of As- and Cu-contaminated soils using white lupin and combined iron and organic amendments.

An aided phytostabilisation strategy consisting of several composite amendments of iron sulphate and organic materials combined with Lupinus albus L. (white lupin) was evaluated for remediation of an As- and Cu-contaminated soil. Iron sulphate was combined with lime, paper mill sludge (PS), olive mill waste compost (OMWC) or holm oak biochar (BC) and applied to a slightly acidic soil with high concentration of As (∼2200 mg kg) and Cu (∼150 mg kg).