Dune Research Articles

Pinus sylvestris had no positive effect on topsoil organic carbon concentration in artificial shrublands

Afforestation in mobile sand dunes, mainly occurring in large arid and semi-arid regions of China, is expected to improve plant diversity and ecosystem function through vegetation restoration processes, which in turn modify SOC and associated soil properties. However, there is a limited understanding of how sand-binding vegetation alters topsoil organic carbon (SOC) sequestration through the vegetation-soil coupling mechanism in semi-arid regions. We compared the differences in soil properties, leaf litter traits, root traits and microbial traits of shrublands and after introducing Pinus sylvestris, evaluated the relative influence weights and driving mechanisms of different modules and key factors on SOC in Horqin Sandy Land. The results showed that SOC in Salix gordejevii shrublands and Caragana korshinskii shrublands was significantly higher than that in their mixed shrublands, and introducing P. sylvestris significantly decreased SOC. The hierarchical partitioning analysis indicated that soil properties, root traits, microbial traits and leaf litter traits explained 42.60%, 30.84%, 18.60% and 7.96% of the variance in SOC, respectively. The contribution of herb root traits to SOC was greater than that of shrub root traits. Multiple regression analysis showed that the introduction of P. sylvestris into shrublands significantly changed the effects of key factors on SOC, mostly negatively. The structural equation model illustrated that soil properties had direct and significant positive effect on SOC, whereas herbal root biomass indirectly affected SOC through soil properties. Our results indicate that the decrease in SOC was due to the change in litter composition after the introduction of P. sylvestris, which reduced the litter quality and slowed the decomposition rate by microorganisms. In addition, P. sylvestris inhibited the growth of herbaceous plants under the canopy and reduced the biomass of herb roots, which directly reduced the available input source of SOC, thus slowed the accumulation of topsoil organic carbon. We present evidence that positive SOC sequestration by the afforestation of shrubs in mobile sand dunes may be weakened by introducing P. sylvestris, which should be considered in future vegetation restoration in sandy areas.

Grain size and shape analysis of recent and paleo sediments along Poyang Lake with insight into its environmental significance

Grain shape is a crucial sedimentological attribute commonly employed for reconstructing depositional environments and transport history. The new dynamic image analysis (DIA) techniques enable testing a large number of individual mineral grains simultaneously and overcomes many shortcomings of traditional visual evaluation. However, there is a relative dearth of comprehensive analysis on large quantities of sediments in recent and geological period to accurately document their grain shape properties and further evaluate their applicability in distinguishing sedimentary setting and its environmental significance. In this study, we measured the grain shape and size of 77 samples collected from modern surface sand (28 beach sand and 17 dune sand samples) and stratigraphic sediment (16 paleo-dunes sand and 16 paleo-lacustrine sand samples) along the Poyang Lake in southeastern China using the DIA method, and optically stimulated luminescence (OSL) dating was used to constrain the age of stratigraphic sediments from two sand hill sections. Also 217 published grain shape data from various sedimentary environments (coastal beach, desert dune and fluvial sand) were compiled as comprehensively assess the applicability of grain shape discrimination for sedimentary setting. Our results show the significant difference on grain shape feature among fluvial, coastal beach and dune sand. Dune sand exhibit the highest values for circularity (Ci), symmetry (Sy), aspect ratio (AR), and convexity (Cx), while fluvial sand displays high Ci, Sy, Cx value, and lowest AR value. This indicate that the grain shape can be a powerful tool for discriminating sedimentary setting. Principal component analysis shows that circularity and aspect ratio effectively describe the shape of the analyzed sediment and are decisive indicators for identification depositional environments, whereas the convexity has limited sensitivity in distinguishing grain edge roundness. The paleo-lacustrine sand (PLS) intercalated within the sand hill profiles returns OSL age of age of ∼ 26.5 ± 1.4 ka, which indicate the emergence of interdune lake rather than high lake level of Poyang Lake. PLS and modern beach sand (BS) exhibiting identical grain shape characteristics to those of modern aeolian dune sand (DS) suggested the occurrence of aeolian-fluvial interaction processes in our study area during the Last Glacial Maximum and present day. The paleo-dune sand (PDS) samples, yielding OSL age of 1.2 ± 0.1 ka, are characterized by higher Ci, Sy, and AR, indicating strong aeolian activity and dune reworking during the past two millennia along the Poyang Lake.

ANATOMICAL CHARACTERIZATION OF STACHYS MARITIMA GOUAN VEGETATIVE ORGANS

Stachys maritima Gouan is a perennial herbaceous plant from the Lamiaceae family. It only grows on sand dunes, especially littoral ones. In Romania it is considered an endangered species, only found in few coastal areas of Tulcea and Constanța counties. Its vegetative organs (rhizome, aerial stem, leaf petiole and leaf blade) were harvested for anatomic analysis.The rhizome showed a secondary structure, with thin suber, compact and thin phloem and compact xylem annual growth rings, while pith was mostly replaced by xylem elements. Aerial stems had the four-ridged shape common in many Lamiaceae, with caps of angular collenchyma protecting four major, semicircular, collateral vascular bundles. Multiple secondary bundles were also found, joined together by sclerified external pith layers. Leaf petiole was filled with undifferentiated parenchyma, made up of large polygonal cells, similar in shape to stem cortex and pith. Leaf blade had a weakly differentiated bifacial structure and was amphistomatic. Stems and leaves were covered by dense, massive, lignified tector hairs. Secretory hairs were small, exclusively peltate, mostly found on stems.

Different but not isolated: absence of reproductive barriers and strong floral divergence between ecotypes of Epidendrum fulgens (Orchidaceae)

Abstract Reproductive barriers and divergent traits may occur between populations of the same species occurring at different habitat types. Here, we investigated the reproductive compatibility and flower morphology of eight populations of Epidendrum fulgens (Orchidaceae) distributed in two different disjunct environments: coastal sand dunes and inland rock outcrops. We investigated potential reproductive isolation barriers using artificial hand pollination experiments, and considering fruit set and seed viability as proxies for pre- and postzygotic barriers, respectively. For morphology investigation, we analysed the shape of flowers using a geometric morphometric approach. Contrary to our expectations, we found high levels of fruit set (0.85) and seed viability (0.73) in crosses between ecotypes, suggesting a lack of reproductive isolation barriers. Regarding floral morphology, canonical variate analysis revealed all floral parts were significantly different between ecotypes (P < .05), while Procrustes ANOVA on symmetric components of shape indicated lateral sepals (P = .005) and ventral sepal (P = .011) were significantly different. Considering that both ecotypes are found on different habitats, the floral morphological divergence may be affected by specific abiotic conditions affecting flower development and/or different pollinator assemblages. Despite the morphological differences, reproductive barriers between ecotypes are absent, suggesting populations from divergent environments may merge upon secondary contact. Our contrasting results highlight the importance of multidisciplinary approaches for providing insights into the processes operating during the early stages of speciation.

Quantitative reconstruction of sedimentary processes, provenance, and binary sources in Horqin Sandy Land, NE China: An integrated approach

As the largest semi-fixed dune field in China, the Horqin Sandy Land (HSL) provides a valuable opportunity to study the surface processes and paleoenvironmental evolution of drylands in the monsoon region. However, limited data and a single qualitative approach hinder our understanding of the sediment erosion and transport process of the HSL. The ability to trace and quantify sediment provenance of the HSL is increasingly needed to properly understand the source-to-sink processes, and to accurately interpret aeolian–fluvial interactions in terms of a comprehensive database and multidisciplinary approach perspective. This study integrates previously existing grain-size, heavy mineral, element geochemistry, Sr-Nd-Hf isotopic, and zircon-geochronological databases with new petrographic, TIMA automation heavy mineral data and statistical analysis. Together, the high degree of recycling of HSL severely limits the provenance identification of element fingerprints, although these elements are largely inherited from the parent rocks and are not affected by chemical weathering. The heavy minerals, Sr-Nd-Hf isotopes, and zircon U-Pb age composition together reveal that the HSL sediments are a binary mixture of the Palaeozoic-Mesozoic igneous rocks in the Great Xing’an Range (GXR) and the Precambrian metamorphic rocks in the Yanshan Mountains. The isotopic end-element mixing models, multidimensional scaling (MDS) diagrams and inverse Monte Carlo models of detrital zircon ages indicate that GXR and Yanshan Mountains account for ∼ 60 % and ∼ 40 % of the source contributions, respectively. Under the strong influence of the northwest to west winds controlled by the Mongolia-Siberian High, detrital material from the GXR is consistently transported to the interior of the dune field and intensively reworked. The Laoha River and the Yangxumu River originating from the Yanshan Mountains provide stable detrital sources for the HSL. In addition, the transverse flow of the Xilamulun River and the West Liao River has provided sufficient space and sediment for the dunes, which is conducive to the full mixing of materials inside the dune field. The sediment in the southeast of HSL shows an obvious Yanshan Mountains source dominance and a grain-size dependence. The coarse fractions (>63 μm) mainly modified from the river channel sand and alluvial plain of the Yangxumu River (∼75.8 %), while the fine fractions (<63 μm) have a strong affinity with the loess deposit of Yanshan Mountains (∼52.4 %). The fluvial-lacustrine deposits during the last glacial maximum served as a temporary transit station, providing a direct dust source for the modern dunes in the HSL region. Aeolian–fluvial interaction controls the geomorphology and landscape evolution of the HSL in the monsoon region; however, it is challenging to derive insights into the landscape evolution from studying surface samples.

Leaf Transpirational Cooling and Thermal Tolerance Vary Along the Spectrum of Iso‐Anisohydric Stomatal Regulation in Sand‐Fixing Shrubs

ABSTRACTTranspirational cooling is crucial for plant thermal regulation to avoid overheating; however, during prolonged and/or acute heat stress it often necessitates stomatal closure to reduce the risk of hydraulic failure due to dehydration. The intricate interplay between thermal regulation, water transport and use may govern plant performance in water‐limited and simultaneously heat‐stressed environments, yet this remains inadequately understood. Here, in a common garden, we evaluated the functional associations among physiological characteristics related to leaf thermoregulation, heat tolerance, xylem water transport, and stomatal regulation in eight shrub species commonly used for fixing active sand dunes in northern China. Our study showed that traits associated with heat adaptation and xylem hydraulics were closely related to stomatal regulation. More isohydric shrub species with higher water transport efficiency possessed stronger transpirational cooling capacity; whereas the more anisohydric species demonstrated greater tolerance to overheating. Moreover, leaf heat tolerance was strongly coordinated with drought tolerance reflected by leaf turgor loss point. These results underscore the importance of stomatal regulation in shaping plant thermal adaptive strategies and provide valuable insights into the coupling of water and heat‐related physiological processes in plants adapted to sandy land environments prone to combined drought and heat stresses.

From lab to landscape-scale experiments for the morphodynamics of sand dunes

From lab to landscape-scale experiments for the morphodynamics of sand dunes

Assessment of Soil Physico-Chemical Properties after Conversion of Sand Dunes into Arable Land in Hot Semi-Arid Climatic Conditions of Punjab

Assessment of Soil Physico-Chemical Properties after Conversion of Sand Dunes into Arable Land in Hot Semi-Arid Climatic Conditions of Punjab

Durability enhancement in self-compacting sand concrete using mineral additives

Purpose The study aimed to explore the effects of mineral admixtures – especially limestone filler (LF), brick powder (BP) and ceramic powder (CP) – on the performance of self-compacting sand concrete (SCSC). It studies their effect on mechanical properties and mass loss when exposed to acidic solutions (H2SO4 5% and HCl 5%) over periods of 28, 90 and 180 days. The study seeks to develop SCSC technology by taking advantage of locally available sand resources. Design/methodology/approach Using an experimental design, the study explores different formulation parameters, including the use of silty sand (AS) and dune sand (DS) in fixed proportions, where AS constitutes 70% and DS 30% of the total sand content. The superplasticizer ratio (SP) and water-to-binder ratio (W/B) are constant with varying amounts of mineral additives. The study immerses SCSC samples in acidic solutions (5% H2SO4 and 5% HCl) for 28, 90, and 180 days to evaluate mass loss and mechanical properties. This endeavor to advance such concrete technology is motivated by the desire to incorporate sand concrete into the realm of self-compacting concrete technology while also harnessing the advantages of locally available sand resources, particularly dune sand, which is abundant in the southern regions of Algeria. Findings SCSC results with mineral additives showed enhanced resistance in both tensile and compression tests, indicating improved durability compared to the reference sample without additives. However, excessive proportions of BP (&gt;60%) or CP led to exceptions in this trend An exception to this trend was observed when BP was added in proportions exceeding 60% or when CP, indicating potential limitations in some additive formulations. Overall, the research provides valuable insights into improving the performance and durability of SCSC through the strategic incorporation of mineral admixtures, contributing to advances in self-compacting concrete technology. Originality/value 1 – Valorization of local materials and recycling of waste: DS, LF, BP and CP, which are available in great quantities in the south of Algeria; 2 – Combination, at the same time, of alluvial sand and dune sand as aggregate and LF, BP and CP as filler. 3 – Application of the design of experiments method methodology for the optimization of these elements of the new sand concrete studied. The new building material elaborated present indeed a technical, economic and environmental interest.

Optimization of alkali-activated ladle slag-fly ash composites using a Taguchi-TOPSIS hybrid algorithm

The effect of multiple mix design factors on the properties of ladle slag-fly ash alkali-activated composites was investigated. Taguchi-TOPSIS hybrid algorithm was adopted to optimize mix design parameters, including ladle slag replacement by fly ash (LSR), sodium hydroxide molarity (SHM), the ratio of sodium silicate to sodium hydroxide (NS/NH), the ratio of alkaline activator solution to binder (AAS/B), and crushed stone replacement by desert dune sand (CSR). The results revealed that the mix proportions of the optimum strength response comprised LSR, AAS/B, SHM, NS/NH, and CSR of 10%, 0.5, 8 M, 2, and 75%, respectively, with a compressive strength of 21 MPa. Conversely, the mixture proportions for superior fresh properties had a flow of 240 mm and entailed LSR, AAS/B, SHM, NS/NH, and CSR of 40%, 0.5, 8 M, 2.5, and 75%, respectively. Additionally, the hybrid method prediction model proved to be robust, with the ability to predict strength and workability at 93 and 100% accuracy. The optimum mixes comprised an intermix of calcium aluminosilicate hydrate and sodium aluminosilicate hydrate gels, with traces of calcium silicate hydrate gel, as identified by microstructure analysis and using ternary diagram system of Ca/Si-Na/Si-Al/Si ratios.

Effects of grazing on the relationship between dominant shrubs and understory vegetation along sand dune stability gradient.

During the process of dune vegetation restoration, understanding how grazing disturbance affects the relationship between plant species is a critical issue in ecological studies. However, there is insufficient evidence on the changes in the interaction between dominant shrubs and understory vegetation under grazing behavior. We aimed to study how grazing and dune stabilization affects the relationship between Caragana microphylla and understory vegetation. We established fencing at various stages of dune stabilization and proceeded to compared the performance indicators (e.g., richness and biomass) and the relative interaction index of understory vegetation and different functional groups along the dune stability under grazing and fencing conditions. Results showed that C. microphylla had facilitation on understory plants, and increased with dune stability, while the facilitation of Caragana microphylla on understory vegetation was stronger under grazing conditions. As sand dune stabilization increases, the facilitation of C. microphylla on understory vegetation diversity decreases significantly. However, there was no significant difference in the facilitation of C. microphylla on understory vegetation biomass at different stages of sand dune stabilization. This is related to the survival strategy of perennials being less tolerant to environmental stress than annuals, because grazing increased the richness of both annuals and perennials while reducing the overall biomass, and in the later stages of sand dune stabilization, and the facilitation of C. microphylla on perennials was higher than on annuals. Our study highlights the importance of the responses of different life-form groups to environmental factors and grazing disturbance during the process of sand dune vegetation restoration, as they play a crucial role in shaping the development of the relationship between understory vegetation and dominant shrubs.

Perched Hydrologic Systems of the Monahans and the Kermit Dune Fields, Northern Chihuahuan Desert, West Texas, USA

Perched Hydrologic Systems of the Monahans and the Kermit Dune Fields, Northern Chihuahuan Desert, West Texas, USA

Thermal analysis of mortar based on crushed dune sand

This study investigates the thermal decomposition behavior of mortars formulated using crushed dune sand and thixotropic polyester resin. Thermal analysis techniques, including Differential Scanning Calorimetry (DSC), Differential Thermal Analysis (DTA), and Gravimetric Thermal Analysis (GTA), were employed to characterize the thermal transitions, decomposition stages, and stability of these mortars. Results indicate that crushed dune sand maintains consistent glass transition (Tg) and crystallization temperatures (Tc) when integrated into the mortar matrix, highlighting its thermal stability. However, the melting point (Tm) varies due to the presence of the resin, which significantly influences the composite’s thermal behavior. Decomposition analysis reveals two major weight loss stages: water evaporation between 200°C to 400°C and organic decomposition of the resin between 700°C to 800°C, with minimal weight change beyond 800°C, indicating thermal stability. The DTA results exhibit distinct endothermic reactions related to dehydration and dehydroxylation, along with a pronounced exothermic peak around 400°C, signifying resin decomposition. Elemental analysis confirms that the crushed dune sand is predominantly silica with minimal impurities, making it suitable for construction applications. This research contributes to a deeper understanding of the thermal behavior of polymer-modified mortars, with implications for enhancing thermal and mechanical properties in construction materials.

Topographic–Vegetation Interactions on an Incipient Foredune Field Post-Tropical Storm

Sand dunes protect the most important economic and ecologically critical landscapes from coastal hazards (storms and high-tide flooding). The characteristics of the dune affect their protective ability. This paper qualitatively and quantitatively assesses the relationships between pre- and post-storm conditions for vegetation and the morphology of an incipient dune system along the South Carolina coast. Field-based dune vegetation and morphology measurements were obtained before and after tropical storm Dorian (2019). Vegetation is assessed with respect to distribution and functional type, and subgroups are introduced to categorize land cover transitions. At the quadrat scale (0.2 m2) following the storm, there was a shift from stabilizer to builder, a decrease of sand (2%), and the vegetation remained consistent at around 61% of the land cover. Transect-level analysis (0.2 m × 1.0 m) revealed distinct variability concerning post-storm morphology change in the extreme study site extents. Dorian resulted in approximately 10% volumetric loss over the entire study site (101 m2). This study demonstrated changes to a dune system following a tropical storm with wind as the dominant forcing factor. This study revealed that vegetation presence is not broadly correlated with reduced levels of post-storm erosion.

Late Pleistocene to present landscape and anthropomorphic change in the Keerqin (Horqin) Sandy Land, China: Insights from sedimentary records

The current distribution of dune fields and sandy lands in northeastern China is closely related to the hydrological environment with fluvial processes often providing sediments for dune formation. The Keerqin Sandy Land (also known as Horqin) incised by the tributaries of the West Liao River and located at the northern boundary of East Asian summer monsoon (EAM) in northeastern China, is sensitive to monsoon system variability. As such, aeolian-fluvial-paleosol sequences in northeastern China are valuable geological archives for reconstructing river system behavior and palaeoclimate since the Late Quaternary. Here we show from analysis of these archives that fluvial systems were active at ∼11 ka likely due to the occurrence of floods at the end of the last glaciation. This was followed by frequent channel migration within the floodplains around 7∼5 ka associated with mid-Holocene monsoon precipitation fluctuation and higher humidity. Sediments from this active Holocene fluvial system along with a more humid climate produced conditions in the Keerqin Sandy Land that resulted in extensive paleosol formation. These findings are consistent with the timing and development of paleosols in other sandy lands in northeastern China. Former channels and floodplains along with a higher groundwater table aided the early development of agriculture in this region: many of the former flood plains are still intensively cultivated and highly productive.

Grain Size Measurements of the Eolian Stimson Formation, Gale Crater, Mars and Implications for Sand Provenance and Paleoatmospheric Conditions

AbstractThe Stimson formation is a late‐infilling eolian sandstone in Gale crater, Mars that formed from sand accumulation in a dune field analogous to the modern active Bagnold dune field, enabling a unique opportunity to compare the past to the present dune fields on Mars. Previous work suggested that the Stimson has a coarser grain‐size distribution than the active Bagnold dunes based on three images of the Stimson. We analyze grain size in the Naukluft and Emerson plateaus of the Stimson by observing 115 images throughout the formation to classify textures and quantitatively measuring grains in eight representative individual images. Results indicate that the Stimson has a primary grain size mode at &lt;200 μm. In addition, more than 50% of the observed Stimson rock targets display a coarser grain population with a long‐tailed distribution including grains ∼600–1200 μm. The primary grain size mode is similar to that observed in the Bagnold dunes, but the coarse grain size mode was neither observed in the Bagnold dunes nor in ripples adjacent to the dune field. Models for saltation mechanics indicate that the favored grain size for eolian transport on Mars, ∼100–200 μm, is independent of atmospheric density, though atmospheric density affects the wind speeds at which grains can be transported by winds. We conclude that the source of the Stimson dunes was more proximal and coarser than the source of the Bagnold dunes and that the paleoatmosphere was likely not significantly denser than the modern Martian atmosphere.

Fluvial-aeolian interactions in a partly confined reach of the Yarlung Tsangpo River, Tibet

Fluvial-aeolian interactions (FAI) exert a primary influence on landscape morphodynamics in arid regions. Such process interactions are well studied for large-scale open systems such as dryland deserts and plains, but little is known about FAI in partly confined valley settings. Here we show how aeolian sand availability and transport pathways and connectivity relationships influence morphodynamic interactions with fluvial processes in a braided reach of the Yarlung Tsangpo River in Southern Tibet, China. Analyses of remote sensing imagery, field data, and the hydrology record show how dune fields and wind systems influence the magnitude and frequency of channel change. While the dunes along the trunk stream have limited impact on river morphodynamics, mid-channel dune fields significantly decrease the frequency of channel adjustment. Combined impacts of valley winds and mountain-valley winds create aeolian sand ramps that stimulate sediment recirculation within this landscape setting.

A hybrid, genetic programming and physically-based predictor of dune geometry

Subaqueous sand dunes are found in many natural environments and pose significant operational challenges. However, classic dune predictors found in the literature fail at predicting equilibrium dune dimensions. In this study, we first investigated the potential of using genetic programming to derive predictive equations of dune wavelength and height. The predictors outperformed existing relationships, yet the equations remain complex due to the intricate physics governing dune evolution. We carried out a global sensitivity analysis to evaluate the most influential parameters of the GP predictors. Finally, we proposed a set of robust predictors, for equilibrium dune heights and wavelengths, relying on basic environmental parameters.

Fixing active sand dune by native grasses in the desert of Northwest China

BackgroundDesertification is the most severe environmental problem in arid and semi-arid regions and has caused great economic loss every year. However, artificial sand fixation barriers function on sand fixation for only 10–20 years. Searching for a native species with long-term sand fixation effect and strong environmental adaptive capacity, and low water consumption is needed. In this study, we investigated the environmental adaption and sand fixation effect of a grass from Poaceae family (Psammochloa villosa) that is indigenous to the desert of Northwest China.ResultsThe results showed that P. villosa has a streamlined leaf form, strong mechanical strength, and flexibility to adapt to wind. Leaf curling of P. villosa under drought decreased water loss rate through decreased evaporation area to adapt to drought. Significant negative relationship between adventitious root length and horizontal root burial depth indicates that adventitious roots help P. villosa absorb water and nutrients from soil under shallow sand burial condition, which enables P. villosa to adapt to different sand burial conditions. P. villosa fixed sand dunes through the distribution of the population at the top of the dune and the vertical relationship between the direction of windblown sand and the direction of growth of P. villosa, which stopped the expansion of the dune.ConclusionsGrowth characteristics of wind and drought tolerant leaf traits and adventitious roots under sand burial indicate that P. villosa is well adapted to dry sandy desert conditions and burial by sand. The distribution of the P. villosa population on the sand dune is a “brake” on its expansion. These findings provide new insight for active sand dune fixation and desertification control using native grass in the desertified regions.

Manufactured soil: A new use for bauxite residue

Bauxite processing residue produced at an Alumina refinery was used to produce manufactured soil. The residue was first acidified and then leached to remove excess salts. Green waste compost was added at rates of 5 and 10 % w/w, with or without the addition of 20 % w/w dune sand. The products were dried, crushed and sieved and the chemical, physical and microbial properties of the materials characterized. Products had an electrical conductivity and pH of 1.0–1.1 dS m−1 and 8.0–8.1 respectively in 1:5 soil:water extracts and corresponding values in saturation paste extracts were 5.4–5.7 dS m−1 and 7.4–7.5. The effective cation exchange capacity was 202–351 mmolc kg−1, exchangeable Na percentage was 41–46 %, Colwell-extractable P was 108–119 mg kg−1 and the Toxicity Characteristic Leaching Procedure showed that extractable metal concentrations were an order of magnitude below regulatory limits so the material can be considered as non-hazardous. Diethylenetriaminepentaacetic acid-extractable Cu, Zn and Mn were below reported critical levels. Addition of compost lowered concentrations of extractable Cr, As and V and drying the material further reduced extractable levels. When the material was dried it shrunk and solidified and the aggregates produced had a low macroporosity and high microporosity and water holding capacity compared with dune sand. Aggregates were very stable as measured by wet sieving. Compost addition increased organic C content, and the size (microbial biomass C) and activity (basal respiration and the activity of enzymes involved in C, N, S and P mineralization) of the soil microbial community. It was concluded that the materials produced had soil-like chemical, physical and microbial properties and could potentially be used as a soil substitute.