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Humic substances (HS) are frequently incorporated into soils to improve soil health and nutrient availability. However, existing literature presents discrepancies regarding the soil-HS interactions and their impact on orthophosphate (inorganic phosphorus (IP)) adsorption, specifically, concerning the influence of soil clay mineralogy on these interactions. This study aims to investigate whether the impact of soluble humic acid (HA) on IP adsorption in semi-arid Mediterranean soils is contingent upon their clay mineralogy. This was tested by constructing IP- adsorption isotherms in the presence and absence of HA of four illite/smectite (I/S) or kaolinitic dominated soils. The results revealed that the addition of HA increased IP adsorption to I/S soils by up to 80%, yet IP did not affect HA adsorption to these soils. This suggests that while HA and IP are adsorbed onto different sites on the I/S clay, HA adsorption probably increases the number of adsorption sites accessible for IP. In contrast, IP and HA adsorption onto the kaolinitic soil was fully competitive: IP reduced HA adsorption and vice versa. It is suggested that new adsorption sites for IP resulted from the HA interactions with the I/S clay planar surfaces. In addition, HA moieties containing cationic (ionized) nitrogen, could possibly interact with clays to increase the number of platelets per tactoid. Unlike I/S clays, kaolinite that possesses low degree of isomorphic substitution, low net negative charge, and high degree of platelets stacking, does not tend to such interactions with HA. Instead, HA will be adsorbed mostly onto the clay edges, competing with IP on adsorption sites. • Humic acid (HA) – inorganic P (IP) adsorption to kaolinitic soil is competitive. • Dissolved HA increases IP adsorption to illite/smectite (I/S) soils by 5 to 72%. • HA increases IP adsorption through interactions with negatively charged clay surfaces. • HA increases the IP-buffering capacity of the I/S soils by up to 60%. [ABSTRACT FROM AUTHOR]

Increasing use is being made of phytoliths for quantitative palaeovegetation and palaeoclimatic reconstruction, and consequently studies of phytolith transport are attracting increasing attention. In this context, we conducted a detailed study of factors affecting the soil phytolith transport in six representative natural soil types in Northeast China. We define a phytolith transport index (T) which indicates that transport rates are the lowest in chernozem and chestnut soils, intermediate in dark brown and albic soils, and obviously higher in black and alluvial soils. Additionally, there are differences in the vertical transport of different phytolith types in the soils; however, the transport characteristics are essentially the same among the different soil types. Transport rates are lowest for tabular and blocky phytoliths, followed by bulliform phytolith. By contrast, the rates for short cell, lanceolate and elongate phytoliths are significantly higher, and, notably, these phytolith types have different size and aspect ratios. The transport of phytoliths is also mainly influenced by mean annual precipitation (MAP), soil pH and soil clay content. Climatic factors, especially MAP, are a more significant factor for phytolith transport than phytolith size and aspect ratio. Overall, our findings are significant for the palaeoenvironmental interpretation of soil phytolith assemblages in topsoils. [ABSTRACT FROM AUTHOR]

A generalized water retention curve (WRC) model in a wide suction range considering the initial void ratio is presented in this paper. Both capillary and adsorbed water in soil pores are considered. Based on the experimental results that the adsorbed water content w a is not dependent on the initial void ratio, a new degree of saturation equation of adsorbed water is established. Meanwhile, a new degree of saturation equation of capillary water at various initial void ratios is proposed with a void ratio-related expression of the air entry value. Compared to Lu's model, only one parameter b is introduced in the established model, which can be easily calibrated using WRCs under two initial void ratios. The measured WRC results of 5 soils are used to verify the proposed model in comparison with the other 3 widely used WRC models. The soil used in the model validation covers a wide range of soil types from sandy soil to clay soil, including clayey silty sand, sandy clay till, clayey silt, expansive soil and lateritic soil. The proposed model is well verified for its ability to describe soil water retention characteristics in a wide suction range at various initial void ratios. [ABSTRACT FROM AUTHOR]

The parameterization of soil hydraulic properties (i.e., porosity and hydraulic conductivity) remains an important source of uncertainty in land-surface and large scale hydrological models, especially for shrink-swell soils, whose soil properties continuously change over time. Much research in shrink-swell soils has been devoted to understanding the relation between soil type, water content, shrinking and cracking, and water retention and hydraulic conductivity curves as well as developing suitable vadose zone hydrological models to estimate the impact on water flow and contaminant transport. However, little is known about the feedback of the shrinking and cracking on surface hydrology and its potential effects on agricultural production and land-atmosphere interactions. Here, using a probabilistic theoretical model linking shrink-swell properties to the soil moisture dynamics at soil matrix to pedon scales, we analyze the two-way interaction between shrinking/cracking status and soil moisture and analyze the impact of shrinking on hydrologic fluxes (i.e., evapotranspiration, percolation). Relying on data from Ships clay soils in Texas, the analysis of the probability density function of soil moisture for various shrink-swell properties and rainfall regimes reveals that shrinking overall contributes to lowering the pedon-scale soil moisture and prolonging the persistence of dry soil moisture states. This persistence of dry states is also associated with a shorter memory timescale in shrink-swell soils. Our results shed light on the impact of shrinking on surface hydrology and, given the expected climate change, calls for more research focusing on land-atmosphere interactions and the potential effects on the persistence of droughts. • A surface hydrologic model for shrink-swell soils is developed. • Evapotranspiration and percolation are significantly affected by shrink-swell soil dynamics. • Soil shrink-swell dynamics increase the persistence of dry soil moisture states. [ABSTRACT FROM AUTHOR]

• Organic matter amendments increase PAW in sand but reduces PAW in clay. • Xeric tree species has improved growth with organic matter amendments in sand but not clay under water deficit. • Biochar no better than compost for improved tree performance. • No synergy found between compost and biochar as a soil amendment. Organic matter is often used as an amendment to attempt restoration of degraded soils to improve tree establishment and growth. One key aim is to increase plant available water in the soil profile. The texture of the soil, the type of organic amendment (e.g. compost or biochar), and the native environment of the tree (mesic or xeric) will impact how successful restoration efforts are. We aimed to determine whether compost and biochar amendments, either individually or in combination, would improve plant available water (PAW) in both clay and sand soils. We then aimed to measure whether changes in PAW would translate into increased water use and plant growth of both mesic (Corymbia maculata) or xeric (Eucalyptus torquata) tree species under well-watered (WW) or water deficit (WD) conditions. Clay and sand soils were amended with compost, biochar or a compost and biochar mix, whilst unamended soils acted as controls. Soil moisture characteristics of the soil mixes were determined with samples in the laboratory. Fifteen replicate pots (6 l) of each soil treatment were then planted with either mesic and xeric tree species. All pots and trees were subjected to either a WW or WD irrigation regime for 7 weeks. WD irrigation was a set percentage of the daily WW evapotranspiration (ET). ET was calculated as total pot mass one hour after irrigation (to allow for drainage) minus the total pre-dawn pot mass of the subsequent day. The tree biomass, biomass partitioning, ET, and tree water status were measured throughout the experiment to understand growth and stress responses. The xeric tree species (E. torquata) grown in sand soil had a significant increase in growth with all three OM amendments but did not when grown in clay soil. In contrast, we found no significant growth response for the mesic tree species (C. maculata) when grown in either clay or sand amended with any OM treatment. The ET of the xeric tree species was greater for all the OM amended soils for both WW and WD plants in the sand soil. This study shows that OM amendments may improve the soil water properties of sand-based soils which in turn can increase the growth of xeric tree species. However, more expensive organic amendments may not be necessary, nor mixing of OM types, as we found no tree growth differences amongst the three different OM treatments. [ABSTRACT FROM AUTHOR]

Soil compaction combined with water deficit may cause a significant decrease in microbial functions. Two texture-contrast sugarcane soils were exposed to the combined stresses of compaction and drought, and microbial responses were investigated going into stress (phase I) as well as their response coming out of stress (phase II). We artificially applied a gradient of bulk densities (0.9–1.5 g cm−3) and water-filled pore space (WFPS, 21–100%) to simulate compaction and drought conditions. PCA results clearly demonstrated the separation of impacts of soil types and the moisture treatments. Additionally, it is evidenced that soil texture can strongly regulate soil microbial response to compaction, as finer texture provides a better local environment for soil microbial community growth, supported by two folds higher microbial biomass carbon content and significantly higher CO 2 respiration in Nitisol (clayey soil) than Planosol (sandy soil). The Structural Equation Modelling (SEM) analysis showed a strongly direct negative effect (path coefficient= −0.59 to −0.61, p < 0.01) of WFPS on the labile C at Phase I and Phase II in both Nitisol than Planosol. Further, soil moisture would govern microbial respiration cross soil types, particularly after removal of compactions which supported by the SEM result (path coefficient= −0.36 to −0.47, p < 0.05). Results from this study have implied the importance in considering the combined effects of soil texture and moisture in assessing compaction impacts and developing associated management regimes. [Display omitted] • Microbial response to compaction varied with soil moisture levels and texture. • Water filled pore space regulates microbial activity at the low moisture level. • Clayey soil showed a greater microbial response to compaction and moisture level. • Clayey soil showed higher resistance to compaction in comparison to sandy soil. [ABSTRACT FROM AUTHOR]

This paper presents the influence of temperature on the residual strength by analyzing shearing tests carried out in a temperature- and velocity-controlled ring shear apparatus. Temperature was applied in steps of cooling and heating ranging between 6 °C and 50 °C at a constant shearing velocity of 0.442 mm/min. Additional tests include the evaluation of the strength at 0.890 mm/min before and after the imposed temperature change. Six basic soil types characterized by different mineralogy, grain size and plasticity, as well as, mixture soils having different proportions of sand and clay, are evaluated and the results are interpreted in terms of their properties. The experimental results reveal that the temperature effect becomes relevant when fine particles and plasticity increase being negligible in the case of the sandy soil. Shear strength reacts immediately to temperature changes and a new residual strength establishes soon. The temperature effect is symmetric. An increase in temperature leads to a decrease in strength, and an equal and opposite trend is observed when temperature decreases. The magnitude of the strength variation is significant in clayey soils. For the case of high plasticity soils, the residual friction angle variation observed during cooling and heating (±50 °C) is around 2°. The strain rate effect evaluated in a smaller number of tests indicated a strain rate strengthening in all the materials tested except for the case of the sandy soil, which also was not reactive to temperature changes. The experiments are calibrated with a velocity, state, and temperature-dependent friction model. • Influence of temperature on residual shear strength have been characterized. • Heating leads to decrease in friction and cooling leads to an increase for high shearing rates. • Relevance of residual friction change with respect of temperature correlates with the soil plasticity. • No effect of temperature was measured for the clean sand tested. • The friction constitutive model developed by Chester (1994) can reproduce the tests performed. [ABSTRACT FROM AUTHOR]

The aim of the study is to determine the correlations between mechanical impacts on clay soil samples and resulting changes in the microstructure of the samples and their IR spectra. For research, soil from a railway subgrade under construction in the Azov-Black Sea region was used. The soil was examined by traditional and modern physical methods and classified as light clay. Clay properties were modified by adding alabaster to the soil, after which the samples with different amounts of alabaster were subjected to mechanical load. A cyclic mechanical impact by the compression method was applied to a clay sample without alabaster, an equivalent to the passage of 400 freight trains along the railway track. The microstructure of samples was studied by electron microscopy which allowed determining the microstructure parameters of the fragments of samples before and after the mechanical action. Samples of clay and clay with the addition of alabaster were subjected to a semi-quantitative express analysis by IR spectroscopy, as a result of which the concentrations of minerals were determined with an accuracy of no worse than 10%. Clay and clay samples with the addition of alabaster were subjected to static uniaxial compression, after which the samples were examined by IR spectroscopy. Comparison of the results of spectral and compression studies made it possible to investigate the correlations between changes in the peak intensities of the IR spectra bands and the concentration of alabaster, as well as the strength properties of the soil. • Adding modifiers to clay soil leads to a change in its strength properties. • Addition of modifiers to the clay soil results in a change in the shape of the infrared spectra. • Changes in the intensity of IR band peaks correlate with the concentration of modifiers and strength properties of clay soil. • Correlation relations are individual for types of clay soils, method of spectra normalization and composition of modifiers. [ABSTRACT FROM AUTHOR]

In this study, field-scale experiments were carried out to analyze the coupling effects of typical agronomic measures and soil types on soil antibiotic resistance genes (ARGs) using high-throughput fluorescence quantitative PCR. The results indicated that agronomic measures enhanced ARG abundance in different soil types. For the same soil type, the enhancement of ARG abundance in response to agronomic measures could be ordered as follows: livestock manure application (257.6–131.7 %) > sewage irrigation (57.6–35.0 %) > plastic film mulching (21.2–5.0 %). Under the same agronomic measures, enhancement of ARG abundance according to soil type was: clay (257.6–21.2 %) > loam (147.8–15.9 %) > sandy (131.7–5.0 %). Furthermore, the contributions of environmental factors in determining ARG abundance in different soil types differed in response to the application of different agronomic measures. Phthalates had the most and least pronounced effects on ARG abundance in sandy and loam soils, respectively. Effects of moisture on ARG abundance were minor in loam soil, but greater in clay and sandy soils. These findings provide new insights into the dissemination of soil ARGs promoted by the adoption of agronomic measures. • Under same measure, soil resistance gene abundance was in order: clay > loam > sandy. • Effects of phthalates on resistance genes in soils were in order: sandy > clay > loam. • Effects of moisture on resistance genes in soils were in order: sandy and clay > loam. [ABSTRACT FROM AUTHOR]

• Contribution of organic carbon (OC) to total specific surface area (SA) is unclear. • EGME SA correlated with water sorption SA, except for OC-rich soils. • OC contribution to SA depended on clay mineralogy and OC content. • OC contribution ranged from 7.5 to 13.9 m2/g per %C depending on clay mineralogy. • For samples rich in montmorillonite, OC negatively contributed to total SA. Soil specific surface area (SA) reflects the quantity and quality of the soil mineral and organic fractions. For soil samples that have similar clay mineral types, clay content and or organic carbon (OC) contents are good predictors of SA. However, the magnitude of the OC contribution to SA for different soil types is unclear, particularly since SA varies depending on which method or probe molecule is used to measure it. Consequently, we set out to (i) quantify the contribution of soil OC to total SA for soils with varying clay mineralogy, and (ii) assess the effect of probe molecule (EGME or H 2 O) and water sorption direction on the contribution of OC to the total SA. We utilized 330 soil samples (clay = 1 to 89 %; silt = 2 to 78 %; OC = 0.03 to 34.9 %) that were grouped according to clay mineralogy and OC content. The total SA was measured using EGME adsorption (SA E) and water adsorption and desorption (SA H2O). The contribution of OC to SA was examined using regression and partial correlation analyses that combined clay, silt, and OC as explanatory variables. Results showed that SA E values were strongly correlated to SA H2O , except for OC-rich soils where SA E was significantly lower than SA H2O. Apart from montmorillonite-rich samples, OC contribution to SA E was smaller than for SA H2O. Organic carbon had a positive contribution to desorption SA H2O for all sample groups, except for montmorillonite-rich samples; OC contribution was 7.5, 10.7, and 13.9 m2/g per %C for illite-rich, kaolinite-rich and OC-rich samples, respectively. There was no significant effect of water sorption direction on the OC contribution to SA H2O. Partial correlation analyses that accounted for clay and silt contents confirmed a negative contribution of OC to SA E or SA H2O for soil samples dominated by montmorillonite clay minerals. We can conclude that for the soil types investigated here (except montmorillonitic soils), OC has a positive contribution to total SA, and the magnitude of the contribution depends on the clay type. [ABSTRACT FROM AUTHOR]

Adhesion between metal surfaces and soil can have significant effects on soil-tool interaction. The cone pull-out test (CPT) and piston pull-out test (PPT) for adhesion assessment were used in this study on smectite, illite and kaolinite clays at different water contents. In the CPT, the tangential adhesion stress (TAS) and cone adhesion (CA) were measured. In the PPT, the normal adhesion stress (NAS) and piston adhesion (PA) were measured. The results showed that the NAS and TAS depended on the type of clay. The ratios of NAS to TAS for smectite and kaolinite had the largest and smallest values, respectively. For all three types, NAS and TAS decreased as the water content (W) decreased. An increase in the thickness of the water film at the soil-metal contact surface reduced the stress required to separate the metal from the soil. The relationship between CA-W and PA-W for the three clay types differed. For smectite, a change in water content had no effect on CA or PA. For illite, an increase in water content decreased the CA and PA. For kaolinite, a bell-shaped curve formed such that, as water content increased, where WLL, CA and PA decreased. For all three clay soil types, NAS and PA were higher than TAS and CA at a specific water content. This demonstrated the effect of the metal-to-soil contact geometry on the adhesion parameters. The NAS and TAS values were classified in terms of clogging potential. Clogging potential is the adhesion of soil to the cutting tools or conveying system. The selection of the use of the CPT or PPT for adhesion assessment depended on the phenomenon being studied. • The metal-to-soil contact geometry does affect on adhesion parameters. • The normal adhesion stress (NAS) was higher than the tangent adhesion stress (NAS). • The piston adhesion (PA) was higher than the cone adhesion (CA). • The NAS and TAS decreased as the water content decreased. • There is linear relationship between NAS and TAS. [ABSTRACT FROM AUTHOR]

Natural and man-made slope failure has been a phenomenon that has caused many deaths, destruction, and environmental damage. The use of bioengineering technique (grasses) has been widely approached for slope remediation work. However, slope failure still occurs even though it has been protected by a few grasses. Many previous findings have reported on root pull out and root tensile strength for different plant species. However, the type of soil was not taken into account. Therefore, this research was carried out to investigate the function of root mechanical properties in different types of soil. The dry and wet sieve analysis tests were performed to know the classification of the soil. In addition to that, the soil mineralogy test was also conducted to support the soil classification. Root tensile strength tests were carried out on well-grown and poorly-grown Bermuda grass toward sandy and clay soil in dry and wet conditions. The dry condition is considered the condition of Bermuda grass in hot weather, while the wet condition is the condition after the raining season. Bermuda grass was chosen since this type of grass is widely applied for slope stabilization. The site locations were chosen in Temerloh, Maran which consist of clay soil. The other locations chosen were Karak, Gambang, Kuantan, Dengkil, Batang Kali, Ulu Yam, Kuala Pilah, Gombak and Sabak Bernam consist of sandy soil. The results show that the single root of Bermuda grass has higher tensile strength in sandy soil with range values from 0.47 to 185 Mpa compared to clay soil with range values from 0.12 to 159.10 Mpa. In conclusion, the results indicate that soil is one of the factors that influence the growth of bioengineering techniques for slope reinforcement. • A bioengineering method is being used as an alternative for slope stabilization. • The soil stability will increase with time as the root grows. • The pull out force was much affected by tensile strength. • In term of tensile strength, the value decreases with increasing root diameter. • Roots have a great impact on tensile and pull out strength. [ABSTRACT FROM AUTHOR]

Since the texture triangle developed by the U.S. Department of Agriculture (USDA) has traditionally been a basic tool in soil classification, a thorough examination of its suitability has been carried out in this research. A total of 256 soil samples from 21 different countries and 35 publications containing both textural (sand, silt and clay percentages) and Atterberg limits data have been analyzed. The soils were classified according to traditional particle size criteria using the USDA texture triangle. On the other hand, the Plasticity index / Liquid limit ratio, a parameter called clay factor (C F) in this research, was calculated and plotted against the percentage of sand to classify the soil according to the texture-plasticity system proposed by the authors in 2018. The evaluation through C F and comparison with the authors' proposal has shown the limitations of the USDA classification, which only determines soil texture in terms of particle size, but not how this texture affects actual soil properties, an aspect that could be very useful. It has been demonstrated that a significant percentage (20%) of soils classified with the USDA system actually exhibit plastic behavior that is completely unrelated to the assigned name (e.g., non-plastic soils classified as clay). However, the fact that about 80% of the classified soils with both systems present the same group designation (∼37%) or are adjacent groups (∼43%), shows that the authors' classification does not break sharply with the textural criteria accepted to date, which is positive if this new proposal is intended to be used as an alternative. Therefore, the proposed classification conciliates plastic and textural properties, allowing to classify the soil in a more accurate way, adjusting it to its real behavior. • The U.S. Department of Agriculture (USDA) texture triangle was tested on 256 soils. • Clay factor (C F = Plasticity index/Liquid limit) was the examining parameter. • 63% of the names assigned by USDA does not match the plastic behavior of the soil. • An innovative proposal combining C F and texture has been examined as an alternative. • The authors' classification is more accurate and realistic than that of the USDA. [ABSTRACT FROM AUTHOR]

• Manure rate had little influence on the improvement of soil physical properties. • Improvement in soil gas transport and Ksat by manure varied with soil and crop type. • Silty soil had better improvements by manure addition than sandy and clayey soil. Manure application and crop rotation are common agricultural practices that can alter soil physical properties and affect soil functions. In this study, we assessed the effect of long-term manure fertilization (24 to 126 years) and crop type on soil hydraulic, aggregate and pore structural properties. Samples were collected from three long-term experiments (LTEs) in Sweden (silty clay, SiC), Germany (silt loam, SiL) and Denmark (sandy loam, SL). Measurements included water retention, air permeability and gas diffusivity measured at five matric potentials −3, −5, −10, −30 and −50 kPa, saturated hydraulic conductivity (K sat), bulk density (ρ b), and water-stable aggregates (WSA). The treatments at the three LTEs included various manure rates and crop sequences (winter wheat, maize, spring barley, and grass/clover). Results showed that long-term manure addition reduced ρ b by an average of 3–6% for all three sites, and improved soil water retention, plant available water and WSA for most investigated plots. However, increasing manure rates for the SiL and SL sites did not result in further improvements in soil water retention, ρ b and water-stable aggregates. The effect of manure on soil pore size distribution, gas transport, and K sat varied with soil and crop type. Manure increased the porosity of pores < 30 µm in the two fine-textured sites and increased the porosity of pores > 30 µm for wheat and maize plots in the SL site. Manure improved gas transport and K sat in the wheat plots and decreased these properties in the barley plots regardless of soil texture. The maize plots in the SL site had well developed pore structure, while the pore structure in the SiL site was relatively poor. Grass plots had poorer gas transport than maize plots in the SL site despite the manure addition. The study shows that improvements in soil physical and chemical properties arising from manure application largely depend on the crops grown and the soil texture. [ABSTRACT FROM AUTHOR]

Combined pollution from microplastics (MPs) and other environmental pollutants has attracted considerable attention. Few studies have investigated the effects of polyurethane (PU) and polypropylene (PP) MPs on available Cadmium(Cd) in different soil types. Here, PU and PP additions affected available Cd and reduced its concentration in soil (P > 0.05). PU and PP reduced available Cd more strongly in clay soil than that in sandy soil. PU and PP improved the soil porous structure and voids and significantly increased the Zeta potential in clay soil (P < 0.05). Dissolved organic carbon and pH in clay soil were significantly negatively correlated with available Cd after PU and PP addition, and Fe(Ⅱ) was significantly negatively correlated with available Cd in sandy soil. PU and PP addition promoted the C-C, CO 3 2-, and C-H functional groups and FeO, FeOOH, and Fe 3 O 4 formation and influenced the effective Cd through adsorption and precipitation. CdCO 3 formation and clay mineral adsorption, and iron oxide formation, influenced the effective Cd in clay and sandy soils, respectively. PU and PP influenced the effective state of Cd by affecting bacterial communities related to carbon and iron cycles. This study is significant for assessing the environmental risks of MPs combined with heavy metals in different soils and their mechanisms. [Display omitted] • Dynamic effects of PU and PP MPs on available Cd in clay and sandy soil types. • PU and PP MPs can reduce available Cd in clay and sand. • CdCO 3 precipitation and iron oxidation adsorption are important processes affecting available Cd. • PU and PP affected the effective Cd by promoting the bacterial community related to the C and Fe cycles. [ABSTRACT FROM AUTHOR]

Many uncertainties exist in geotechnical engineering. Spatial variability is a type of uncertainty that has received more and more attention in recent years. Scale of fluctuation (SOF) is a parameter for measuring the spatial variability of soil properties. To investigate the proper method for computing the SOF of soil properties, two types of methods (auto-correlation function method (ACM), and variance reduction method (VRM)) are compared theoretically and numerically, and the influence factors, such as number of data points involved in curve fitting for the auto-correlation function (ACF) or variance reduction function (VRF) and sampling interval, on the SOFs are analyzed. To improve the accuracy of curve fitting for the ACF or VRF, a weighted least squares (WLS) method is proposed, in which the weight of each data point of sample function decreases with the increasing of lag distance between two points in a random field. Three types of soil parameters, including the CPT, the physical, and the hydraulic parameters, are tested by in-situ and laboratory tests, and the SOFs of these parameters are computed. Computation of the SOFs proves that the VRM combined with the suggested WLS is a good method for computing the SOFs of soil properties. Comparison of the SOFs shows that there are negligible differences among the three types of soil parameters of clay layers in Hefei, which is further proved by the Wilcoxon test from a statistical point of view. By using the VRM combine with WLS, the SOFs of clay are computed based on 509 sets of CPT data from 34 sites in Hefei. The statistics of SOFs can give a reference for the selection of SOF for reliability analysis or reliability-based design of geo-structures with spatial variability. • The auto-correlation function method and variance reduction function method (VRM) are compared thoroughly. • A weighted least squares method (WLS) is proposed in which the weight decreases with the lag distance. • The VRM combined with WLS is suggested to compute the SOFs of soil properties. • Spatial variability is an inherent property of clays. [ABSTRACT FROM AUTHOR]

• Mixed forests show a higher soil erosion control benefit than monocultures. • Tree-shrub mixtures reduce runoff and sediment more than tree-tree mixtures. • Mixed forests have the strongest positive impact on soil erosion control in dry areas. • Mixed forests are found to affect soil erosion most efficiently after 20 years of tree growth. • Mixed forests have the highest impact on soil erosion control on slopes of 16–20°. Soil erosion poses a major threat to the sustainability and stability of global terrestrial ecosystems. Mixed forests have more advantages in restoring degraded land and enhancing soil fertility than monocultures, but their influence on soil erosion remains uncertain. Therefore, we presented a meta -analysis consisting of 261 paired observations of mixed forests and the corresponding monocultures from 65 studies to evaluate the effect of tree diversity on soil erosion in China. The results showed that compared with monocultures, mixed forests significantly reduced the annual runoff and sediment yield by 17.4% and 23.6%, respectively. Tree-shrub mixtures showed more efficiency in reducing runoff (24.2%) and sediment yield (32.1%) than tree-tree mixtures. However, the positive effect of mixed forests on soil erosion control was significant > 20 years after stand establishment. Mixed forests showed the highest capacity to control soil erosion at slope angles of 16°-25° (runoff: 27.7%; sediment yield: 37.7%). In terms of soil textures, mixed forests performed better with respect to soil erosion control on sandy soils (runoff: 21.4%; sediment yield: 30.1%), whereas significant differences were not observed between different stand types on clayey soils. In addition, in the dry areas (humidity index (HI) < 30), mixed forests conferred the greatest benefits in reducing runoff and sediment yield (25.8% and 33.0%, respectively). Our results indicate that increasing tree species richness is a suitable approach to controlling soil erosion in China. This research provides a scientific basis for the management and sustainable development of forest ecosystems in the future. [ABSTRACT FROM AUTHOR]

• Higher values of the site parameters leads to higher responses. • The effect of pounding could be either destructive or beneficial. • The soil type has a significant effect on the response of the colliding buildings. The effect of the soil type on buildings experiencing pounding during earthquakes is investigated in this study using the incremental dynamic analysis and fragility assessment methods. Three 3-D structures with different number of storeys (4, 6 and 8) were considered in this study. Three pounding scenarios between these three buildings were taken into account, i.e. pounding between 4-storey and 6-storey buildings, between 4-storey and 8-storey buildings and between 6-storey and 8-storey buildings. First, the effect of the site parameters was investigated so as to take into consideration the values that lead to higher responses. Then, the effects of earthquake-induced pounding between buildings founded on a specified soil type for these three pounding scenarios were analysed and compared with no pounding case. Finally, pounding for these three scenarios was studied under different soil types defined in the ASCE 7–10 code (hard rock, rock, very dense soil and soft rock, stiff soil and soft clay soil). The results of this study indicate that the effect of pounding follows two general trends which are destructive and beneficial. Also, the vibrating buildings were found to be more vulnerable to damage due to pounding when they are founded on the soft clay soil, then when they are founded on the stiff soil, then when they are founded on very dense soil and soft rock, and finally when they are founded on the rock and hard rock. [ABSTRACT FROM AUTHOR]

Highlights: [•] Studies on three soil types to determine the effect of harvest method on microclimate. [•] Soil temperature increases at burning were in order of sand soils>clay>muck. [•] Temperature increases dissipated much faster in clay soil than muck soil. [•] Burning may have minimal impact on soil microflora and fauna at the studied depths. [•] Crop canopy damage by frost is more likely to occur with green cane harvest. [Copyright &y& Elsevier]

Abstract: The soil hydraulic conductivity (K) is an important parameter for understanding soil hydrologic processes. K varies with time, soil type, and irrigation method. Understanding and predicting the temporal variability of K are required for irrigation design and numerical analyses. The objective of this study was to investigate and evaluate the temporal variability in K from April to September of 2008 in two soils, clay loam (CLS) and sandy loam (SLS), and two irrigation methods, furrow irrigation (FIM) and drip irrigation (DIM). Five sets of infiltration measurements with five replications were taken in grape fields using a tension infiltrometer at supply h values of −15, −6, −3, and 0cm. The results showed that K had significant temporal differences under all supply h values. Generally, K initially exhibited high values and decreased from April to September. K of SLS was always significantly higher than that of CLS. K values were lower and varied more for FIM than for DIM, but showed no statistically significant difference between the two irrigation methods. About 1.3 to 2.9 times differences existed between the maximum mean K (in April) and minimum mean K values (in July/September) through the whole growing period. However, the relative errors between the calculated K and measured K diminished within 10% when K was estimated using a regression to adjust K to the number of irrigation events. These results contribute to a more accurate description of K for irrigation design and water flow modeling. [Copyright &y& Elsevier]

Abstract: Agricultural management practices can have a significant effect on the emissions of nitrous oxide (N2O) from soils. The aim of this 2-year study was to investigate the effects of no-till (NT) and reduced tillage (RT) practices on annual fluxes of N2O from different soil types typical for the boreal region of northern Europe. We measured the fluxes of N2O in conventional tillage (CT) and NT at four sites of which two also had RT treatment. No-till and RT practices had been implemented 8–10 years before our study was initiated. Chamber measurements were carried out fortnightly in 2008–2010 on clayey (sites 1–3) and coarse (site 4) soils. Annual cumulative emissions of N2O varied from 2.4 to 8.3 in CT, 2.5–6.5 in RT and 4.9–10.2kgN2O-Nha−1 in NT. High peaks in measured N2O fluxes occurred during and after thawing of the soil in April and after fertilization and high rain events. No-till or RT did not have any significant effects on soil C or N stocks or potential denitrification of the 0–20cm soil layer. Dry bulk density and water-filled pore space (WFPS) were generally higher under NT compared to CT, most probably being the main reasons for the increased N2O emissions in the NT systems. Soil temperature varied less in NT by being higher during the colder periods of the year and slightly cooler during hot summer days. In conclusion, our results indicate that NT induces a risk of increased N2O emissions in clayey soils in small grain spring cereal agroecosystems in Northern European boreal climate. [Copyright &y& Elsevier]

Abstract: The development of new technologies for use in field soil survey has produced powerful new quantitative tools for assessing soil physicochemical properties in-situ. One such technology, portable X-ray fluorescence (PXRF) spectrometry, has shown considerable promise in evaluating elemental concentrations in soils for a wide variety of applications. Less research is available on how PXRF can be applied to quantify soil physical properties (e.g. soil texture). This study evaluated the feasibility of predicting soil clay and sand contents from PXRF data on 584 soil samples collected from highly diverse regions of Louisiana and northeastern New Mexico (Capulin Volcano National Monument), USA. An Innov-X Delta Premium PXRF was used to sequentially scan soil samples under both field and laboratory conditions and assess 15 elements (K, Ca, Ti, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Zr, Ba, and Pb). Elemental concentrations were then related to soil textural data processed through traditional laboratory methods with multiple linear regression. Among all elements evaluated, Fe and Rb showed particular significance for soil textural prediction. The regression models for sand and clay contents of both study sites were strongly correlated to soil textural separates with PXRF-soil texture R2 of 0.862, 0.959, 0.892, and 0.780 for Louisiana sand and clay, and Capulin sand and clay, respectively. Independent validation sub-datasets confirmed that PXRF readings can be used to estimate soil textural parameters with high R2 values of 0.854, 0.682, 0.975, 0.891, 0.875, and 0.876, and low RMSE values of 5.53%, 5.92%, 2.68%, 6.26%, 5.43%, and 2.66%, for Louisiana sand, silt, and clay and Capulin sand, silt, and clay, respectively. The RMSE values of clay are substantially lower than those reported in previous studies using other proximal sensing techniques. While regional differences may require localized standardization of the PXRF with a unique combination of elements germane to the study area, PXRF shows considerable promise as a technique for rapidly assessing soil textural separates in-situ. [Copyright &y& Elsevier]

Abstract: This study examines the acidification behaviour and rate of sulfidic-sulfur oxidation in the incubation method that is currently used in soil taxonomies to identify sulfidic materials, for some clayey textured soil materials. ‘Sulfidic’ in these taxonomies identifies that a soil material is capable of becoming extremely acidic (i.e. pH<4) as a result of oxidation of sulfide minerals contained in that soil material. As well as examining incubation slabs of acid sulfate soil materials with the standard 10 mm thickness, the utility of thinner (i.e. 2 mm thick) incubation slabs of these soil materials for identification of sulfidic soil materials was also examined. The clayey soil materials in the 2 mm thick slabs exhibited more rapid sulfidic-sulfur oxidation and acidification and resulted in fewer false-negative sulfidic soil material identifications than did the use of 10 mm thick slabs. However, the rates of sulfidic-sulfur oxidation and sulfide-derived acidification within the slabs (whether 2 mm or 10 mm thick) were not always rapid enough during incubation for the full expression of acidification to be evident within the maximum incubation duration of 8 weeks required by soil classification taxonomies. The results indicate the incubation method for determination of the sulfidic nature of soil materials for soil classification purposes could be improved to reduce the risk of false-negative identification by: i. allowing the use of 2 mm thick slabs, and ii. changing the maximum duration of incubation from 8 weeks to until a stable pH is reached after at least 8 weeks of incubation. [Copyright &y& Elsevier]

• We evaluated how tree functional traits vary across two contrasting savannas. • In typical savanna – prevail fertile soils with good water-holding capacity. • In alluvial savanna – sandy soils with a low water-holding capacity are prevalent. • Tree species on alluvial savannas tend to adopt acquisitive strategies while on typical savannas invest in water conservation and fire tolerance. Environmental filters and functional adjustments of species to local conditions are major determinants of plant communities in stressing habitats. We set out to understand the role of different substrates in functional trait variation in wood plants by investigating key functional traits at the community and intraspecific levels in different types of Brazilian savanna: two sites of alluvial savannas (lowland savannas that occur in old alluvial deposits in riverbeds with sandy soils and low water-holding capacity), and two sites of typical savannas (upland savannas that occur in interfluvial zones, far from the influence of rivers, in which clay soils with higher fertility and water-holding capacity predominate). We conducted this study in four sites with savanna vegetation in the northeast region of the Cerrado Biome, nearby the transition with the Amazon. In each site we sampled six functional traits for each tree species: leaf area, leaf thickness, specific leaf area (SLA), stem-specific density, relative bark thickness and maximum plant height. We sampled 101 wood species, ranging from 26 to 62 species within each site. In both community and intraspecific levels, alluvial savanna plants showed higher SLA and specific-stem density, and lower leaf area, leaf thickness, bark thickness, and plant height compared with the typical savanna. We also found that, at a given leaf thickness, species from typical savanna exhibited ∼20% higher SLA. In addition, at a given plant height, typical species showed ∼56% higher bark thickness and ∼20% lower specific-stem density. Our findings suggest that savanna tree species growing on alluvial savannas tend to adopt strategies related to water acquisition while species growing on typical savannas invest in both water conservation strategies and protection against high-intensity fires. We conclude that water deficit and fire, both related to substrate properties, play a key role in determining the woody plant communities functioning in savannas. [ABSTRACT FROM AUTHOR]

Fire is a natural phenomenon that affects the Earth's biogeochemical cycle. Wildland fires are increasing in frequency and magnitude, possibly owing to climate change. In addition, fire is applied as a tool in agro-ecosystem management. However, several detrimental effects on soil properties, particularly on soil aggregate stability, might occur. A general explanation is that "the effects of fire on soil aggregate stability in soil with high clay content, calcium carbonate, and Fe and Al oxides as the principal cementing substances cause gradual improvement in aggregate stability, following fire-heating severity." In short, the higher the fire severity, the higher is the aggregate stability. A meta-analysis was conducted for assessing the laboratory and field studies to verify this concept. The Scopus® platform was used to search for the literature related to " soil aggregate stability" AND fire OR heating AND clay OR " clayey soil." A total of 10 studies were selected with 16 soil types, 244 burned or heated samples, and 160 control samples. The meta-analysis was performed using RevMan 5.3 software. Meta-analysis was delineated according to the following assumptions: a) field and laboratory studies were tested as two independent subgroups, and a pooled effect was subsequently calculated; b) a random-effects model was used; c) mean differences with 95% confidence intervals were computed for continuous variables. Laboratory and field measurements showed dissimilar effects on soil aggregate stability and evidenced positive effects in the laboratory experiments compared with those in the field. Aggregate stability measured in the laboratory increased by 2.80% after heating. Fire effects measured in the field did not show a significant increase in soil aggregate stability (−0.16%). The overall effects of combined subgroups showed an aggregate stability improvement of 1.49% (confidence intervals 0.80% to 2.17%). However, the weight of the results from the laboratory studies played an important role in the overall effect. The soil clay content was found to be inversely associated with aggregate stability, i.e., the lower the clay content the higher the aggregate stability in soil subjected to fire heating. In conclusion, the aggregate stability of clayey soils rich in Al and Fe oxides does not necessarily improves following fire heating. [Display omitted] [ABSTRACT FROM AUTHOR]

• Pressure plates and dew point method showed similar soil water contents at −15,000 hPa. • The physiological wilting of plants is both plant species and soil dependent. • Soybean plants may be less sensitive to water deficits than maize and sunflower plants. • The matric potential at plant wilting was lower than hydraulic cut-off and −15,000 hPa. The lack of a continuous network of water-filled pores necessary for the flow of water in the soil has been related to the wilting of plants as well as to the limitations of soil sample equilibrium in pressure plates. The objectives of this study were: (i) to quantify deviations of the soil water content measured in pressure plates and dew point measurements at a matric potential of −15,000 hPa (commonly defined as the permanent wilting point), (ii) to determine the soil matric potential at which the physiological wilting of different plant species occurs in soil with contrasting texture, and (iii) to evaluate if the wilting of plants occurs at the hydraulic cut-off in soil. An experiment was conducted to determine the soil matric potential at which wilting of sunflower (Helianthus annuus L.), maize (Zea mays L.) and soybean (Glycine max L.) occurs in four soils with clay contents ranging from 7 to 57%. Soil water retention characteristics were determined by the pressure chamber and the dew point technique. Soil water retention data were fitted to empirical models for estimates of soil matric potential and water content at the hydraulic cut-off. The water contents at −15,000 hPa in samples equilibrated in pressure plates was similar to those obtained from the dew point method in our soils. Our results show that physiological wilting of plants is both plant species and soil dependent. In soils with low clay contents, different plant species wilted at similar water contents. However, in the clayey soils, the different crops showed different abilities in the uptake of water from the soil, where soybean wilted at significantly lower water contents than the other two species. The values of matric potential at the permanent wilting point found in our study were considerably lower than −15,000 hPa, suggesting that the commonly used definition of permanent wilting point as water content at −15,000 hPa is incorrect. [ABSTRACT FROM AUTHOR]

• Native forest substitution to pine plantations alters C, N and P pools. • Soil type determine the C, N and P stocks and stoichiometry response. • Pools in low clay and dominant low-activity clay soils are more affected. • Andisol soil appeared to be more resistant to biogeochemical alteration. Natural forests conversion to intensively managed forest plantation is an expanding land-use change that could profoundly impact C and nutrient terrestrial cycles. Here we assessed how different soil types respond to changes in the C, N, and P major biogeochemical pools by comparing paired natural broadleaf deciduous forest and pine plantation across five different soils with contrasting mineralogy. We quantified major biogeochemical stocks in all soil compartments to a depth up to 240 cm, including the forest floor. Our result showed that soils' C, N, and P stocks and stoichiometry do not respond equally to this land-use change. Deep soil biogeochemical pools (120–240 cm) contributed substantially to the total soil stock in most sites (up to 40% for C, 47% for P, and 52% for P). Elemental depth distribution was significantly modified because of forest substitution, and some sites displayed a significant stock reduction in deep soil compartments (>120 cm). Whole mineral soil C and N stocks were generally lower in the planted forest, while these stocks in litter layers were significantly different between soil and forest types (p < 0.001). C and N stocks in soils with low clay content or low activity clays were more significantly affected by forest substitution. On the other hand, soils with moderate to high clay content and dominant high activity clay were only mildly affected by this change. Phosphate and ammonium available pools were more affected in low activity and low clay content soil. P pools, and consequently C:P and N:P ratios in mineral soils, vary significantly between soil types. Our results corroborate that soils with contrasting properties respond differently to native forest substitution to intensively managed plantations and that the magnitude of this response seems to be controlled mostly by clay mineralogy. [ABSTRACT FROM AUTHOR]

• Vegetation covariates are main soil formation factors for boreal biome studied. • LiDAR-derived canopy height model (CHM) and gap fraction had high variable importance. • Soil property predictions for peatlands had lower modeling uncertainties. • Random forest models and SVMs had comparable accuracies for classification. This study aimed to improve the accuracy in modelling the properties of forest soil by employing a variety of remotely sensed data. In addition to the commonly used multispectral satellite imagery, airborne LiDAR (light detection and ranging) data were exploited to derive detailed vegetation properties and topographic variables. Random forest (RF) and support vector machine (SVM) approaches were applied to classify soil types in terms of texture, calcareous substrate reaction to hydrochloric acid, and ELC (Ecological Land Classification) moisture regime. The developed methods were tested on data acquired over a boreal region (49° - 50° N, 81° - 84° W) with a combined area of 4,085 km2 in the Great Clay Belt (GCB) region, Ontario, Canada. Compared with the field-collected data, the overall accuracies and kappa coefficients of the retrieved soil properties were greater than 0.7 and 0.5, respectively. The accuracies attained between the RF and SVM approaches were similar, but in general the highest accuracies were achieved by the RF method. The models developed for the whole GCB regions generated accuracies comparable to those for the three sub-regions. The lowest modelling uncertainties occurred in areas dominated by peatland, whereas the highest modelling uncertainties existed in the regions with dry moisture regime or clayey soil at the surface. The results also showed that environmental covariates corresponding to vegetation were most important in the prediction of soil properties. Specifically, canopy height model (CHM) and gap fraction derived from LiDAR data, were among the most important variables. The inclusion of LiDAR-derived covariates demonstrated potential, applied in addition with topographic and climatic covariates and optical imagery. CHM pertains to the vertical dimension, and gap fraction relates to the density of the canopy layer, respectively; both covariates that offer supplemental detail that is not necessarily ascertained for the canopy by optical imagery. [ABSTRACT FROM AUTHOR]

The present study focuses on the compositional analysis and phase relationship of soil mass and their role to trigger landslides in the Babai River watershed, Siwalik zone of Nepal. A total of 76 landslides are selected for sampling and further analysis among 769 active landslides from the total study area. For the classification of soil, the Unified Soil Classification System (USCS) is adopted by using both the sieve and hydrometer analysis. The centered log-ratio (clr) and mean component fraction of sand, silt, and clay are obtained from the compositional analysis by using R and CoDapac v.2.02.21 software. Correlation of phase relationships like moisture content, unit weight, specific gravity, void ratio, porosity, and degree of saturation of each soil samples are obtained. The results indicate that the degree of saturation is highly correlated with moisture content and void ratio but less correlated with the specific gravity and dry density. Furthermore, the highly correlated variables are checked by multiple regression analysis and the best-fitted regression equation was obtained from the phase relation. The centered log-ratio and mean log of silt/clay fraction indicate that silt and clay constituents in the soil are responsible for the landslide initiation in the study area. • Soil component analysis and phase relationship can provide their role for landslides • Compositional statistics was used for data analysis • Landslides characterized by soils with dominant silt-clay fraction • The source of clay in the landslides is shale or weak mudstone [ABSTRACT FROM AUTHOR]

• Potential for AI techniques to identify changes in geology is explored. • Data decomposition into feature-based sub-series accentuates their features. • The PSO-SVM model can be useful in providing accurate predictions. Detecting sudden changes in geological conditions (e.g., karst cavern and fault zone) during tunnelling is a complex task. These changes can cause shield machines to jam or even induce geo-hazards such as water ingress and surface subsidence. Tunnelling parameters that relate closely to the surrounding geology have proliferated in recent years and present a substantial opportunity for the application of data-driven artificial intelligent (AI) techniques that can infer patterns from data without reference to known, or labelled, outcomes. This study explores the potential for support vector machines (SVM) to identify changes in soil type during tunnelling towards reducing the possibility of jamming and geo-hazard development. All tunnelling data were pre-processed to convert time series data into feature-based sub-series. A selection of the most popular parameter optimisation algorithms was explored to improve the accuracy of the AI predictions. Their relative merits were evaluated through comparisons with a recent pipejacking case history undertaken in gravel and clayey gravel soils. The results highlight an exciting potential for the use of optimisation algorithm-based SVMs to identify changes in soil conditions during pipejacking. [ABSTRACT FROM AUTHOR]

• Cave-ins are still frequent in the construction industry and present a serious risk for workers. • A comparison of jurisdictions and construction guidelines is presented. • A review of recent research work on cave-in risks with finite element analyses is presented. • Based on those, research needs for sensitive clay cave-in risks are proposed. Cave-ins are very frequent in the construction industry and present a very serious risk for workers who operate inside trenches or excavations. Studies show that excavations or trenches in Quebec sensitive clay soils are extremely hazardous due to possible severe and sudden loss of soil shear strength. Many North American and European construction safety authorities have already adopted proper methods and excavation protection practices according to their soil classification. This paper reviews existing construction codes and guidelines, as well as published research studies related to worker safety and protection in excavations and trenches in sensitive clay soil. The paper also discusses the needs for research on prevention strategies to eliminate potential cave-in risk sources from occurring in Quebec sensitive clay soil. [ABSTRACT FROM AUTHOR]

In Zimbabwe, because of shortages of land, there is need to establish whether soil fertility improves over time in abandoned fields. A study was undertaken in 2015 to characterize fertility status of abandoned fields in smallholder farming areas located in Buhera and Hwedza districts in Zimbabwe. Abandoned fields were divided into four categories based on years of being abandoned (0–5, 6–10, 11–20 and ≥ 20 years) across two soil types and agroecological gradient made up of four regions (AER II to V) where annual rainfall decreases from AER II to V. Soil samples were analysed for pH, N, P and K using standard laboratory methods. A survey was conducted to determine adequacy of nutrient resources used. Soil nutrients did not significantly vary (p > 0.05) with period of abandonment but varied with soil type and agroecological regions. Clay soils and soils from AER V had significantly high N, P and K content. In terms of adequacy of nutrients across all the three factors, N and P content were below required recommendations for crop production whilst K was adequate and soil pH was too acidic. With regards to fertilizer use, majority of the farmers failed to purchase mineral fertilizers because their annual cash earnings were far below money required. As a result 91% of the farmers were failing to apply recommended fertilizers for sustainable yields. In conclusion, abandoned fields in Zimbabwe's communal areas do not restore soil fertility regardless of period to which a field has been abandoned, soil texture or agroecological region. The fertility of these abandoned soils remains poor and too low for crop growth. Farmers are financially unable to meet soil nutrient requirements to improve fertility of their abandoned soils. These findings are important in determining appropriate measures to restore soil fertility and in determining efficient land use policing and planning measures. • Soil fertility of abandoned fallow fields is too low for crop growth. • Soil fertility of abandoned fields does not improve regardless of period of abandonment, soil texture or agroecological region. • Smallholder farmers are socioeconomically unable to apply adequate mineral fertilizers for sustainable yields. [ABSTRACT FROM AUTHOR]

Urbanisation involves major changes in environmental conditions such as light, temperature, humidity and noise levels, but the effect of urbanisation on soil conditions and soil biodiversity has received less attention. The reported effects on species richness across a rural to urban landscapes are not unequivocal. Positive, negative and neutral effects have been found, but what is causing this ambiguity in the relationship between species richness and urbanisation is poorly understood. Here we tested whether and how urbanisation affects isopod diversity and whether this depends on habitat soil type. We recorded isopod species presence and soil type in each 1 km2 grid cell in a 500 km2 area in and around the city of Amsterdam, the Netherlands. We analysed the relationship between the number of species and the most important traits (body size and drought- and inundation resistance), the percentage built-up area, and soil type (peat or clay) across a rural-urban landscape gradient. Because many studies find a negative effect of urbanization on biodiversity, we expected a decrease in isopod species richness by increasing amount of built-up area. We found a negative association between isopod species richness and the amount of built-up area across the rural-urban landscape gradient when rural soils contained clay, while for rural soils containing peat the highest species richness was found at intermediate levels of urbanisation. Hence, the relationship between isopod species richness and the level of urbanisation was mediated by soil type. We also found a significant relationship between percentage built-up area and functional traits, irrespective of soil type. Specifically, the percentage built-up area showed a positive correlation with isopod drought resistance as well as body size. These results together demonstrate (1) that soil type variation introduces an important, but often overlooked context-dependency in the effect of urbanisation on biodiversity and (2) that a functional trait approach is an important tool for understanding general effects of environmental change on biodiversity, irrespective of context-dependency. • Urbanisation effects on soil fauna diversity depend on soil type. • Community mean drought resistance and body size of isopods increase with urbanisation. • Functional traits of soil fauna species predict shifts in biodiversity. [ABSTRACT FROM AUTHOR]

• Saffron (Crocus sativus, L.) fields in highly productive areas in Morocco are infested with the most damaging nematodes. • PPN assemblage is strongly impacted by environmental factors. • Uses of infected saffron corms enhance dissemination of highly damaging endoparasitic nematodes. • Specialized endoparasitic migratory nematodes are a serious threat to Saffron (Crocus sativus , L.) production in Morocco. • Ecological preventive and curative measures in both nursery and field production are needed. Plant-parasitic nematodes (PPN) are the most destructive of all plant pathogens. They are an economically important group of soil pathogens, causing significant annual damages of up to 25% of world crop production. Morocco is considered to be a highly productive country for the colorant/medicinal/spice saffron (Crocus sativus L.). Taliouine and Taznakht regions are the most productive areas of this valuable neutraceutical. Due to its metabolic profile, and growth forms, saffron is susceptible to many plant diseases, including plant-parasitic nematodes (PPN). This work aims to assess the diversity of PPN communities in soils of Taliouine and Taznakht regions to facilitate understanding of links between their assemblages with biotic and abiotic parameters. Herein, nematode communities were characterized in 163 soil samples collected from 11 rural communes characterized by altitudinal gradients in Taliouine and Taznakht regions. Fifteen PPN genera belonging to 12 families were identified, among which the four genera Ditylenchus , Aphelenchoides, Pratylenchus and Helicotylenchus , potentiate serious limiting factors in saffron production. Their frequencies are respectively 92, 49, 48 and 36% in the area of Taliouine, while in Taznakht they represent 95, 69, 33, and 28% respectively. Regarding the assessment of diversity at different sites, the genus richness (R) index ranges from 2 to 10 distinct genera, whereas the Shannon diversity (H') index varies from 0.9 to 1.5 and the Evenness (E) index tends to 1. The Co-inertia analyses revealed a substantial relationship between nematode communities and soil types. Soil texture is the major factor influencing the presence and the abundance of a considerable portion of genera. Multivariate analyses (MBPLS) indicated links between humidity, rainfall, minimum temperature and PPN taxa, though maximum temperature did not have an impact. Ditylenchus, Helicotylenchus, Pratylenchus and Paratylenchus were related to the humidity and silt soil that developed in Taliouine. Aphelenchoides , Tylenchus , Tylenchorynchus and Dorylaimus were more prevalent in rainy locations and clay soils of Taznakht. Suitable nematode controlling approaches may be applied and preventative measures should be considered at nursery and field level. [ABSTRACT FROM AUTHOR]

Southern Brazil abounds with granitic hills capped by intricately distributed soils most of which have been classified as Entisols or Inceptisols in medium- and small-scale soil surveys. However, field observations have revealed substantial texture gradients that are consistent with better-developed soils; also, the physical, chemical and mineralogical properties of the soils suggest that they are only slightly to moderately weathered. In this work, we examined the influence of formation-related factors and processes in soils from two granite toposequences. The eight soil profiles studied for this purpose were shallow, their C horizons occurring at depths of less than 100 cm. The low degree of flocculation and the fine/total clay ratio of the soils suggest that lessivage, which contributed to the development of the texture gradient in six of the profiles, was the main pedogenic process responsible for the formation of these soils. The soils at topographically high points were dystrophic or allitic, whereas those at low points were eutrophic. Based on their K i values, the soils were weathered to a medium extent, which is in conflict with their low clay activity and cation exchange capacity. On the other hand, the Fed/Fes ratios of the soils were consistent with strong weathering, which in turn was consistent with their pH and exchangeable Al values. The iron oxides contents increased with increasing depth in the profiles as a result of lessivage. Feo/Fed ratios were suggestive of a prevalence of crystalline iron oxides. Increased substitution of Al in Fe oxides in the topographically higher soils further confirmed their increased weathering. Based on the foregoing, the soils were classified as Ultisols/Alfisols, Entisols and Inceptisols, the last series being less frequent than suggested by existing soil surveys. The transitional nature of these soil classes reflected in the presence of Ultisols/Alfisols with a thin B horizon, and also of argilluvic Inceptisols. • In southern Brazil granitic hills are present at various places. • Environmental conditions have facilitated the formation of a texture gradient. • Advanced pedogenic processes occur in shallow soil profile with primary minerals. • Granitic soil distribution shows discrepancies in relation to soil-landscape model. • Transitional character is frequent between Ultisol and Inceptisol classes. [ABSTRACT FROM AUTHOR]

To enable the detection of taeniid eggs in environmental samples, a sensitive technology is required. In this study, we validated the effectiveness of a digital droplet Polymerase Chain Reaction (ddPCR) assay for detection, identification and absolute quantification of taeniid DNA from artificially contaminated soils with varying numbers of taeniid eggs using a set of universal primers, JB3 & JB4.5. The results showed that the number of cox1 copies detected increased gradually for both species with the number of taeniid eggs added to the different soil types. The highest cox1 DNA copies recovery for Taenia solium and T. lynciscapreoli was from the sand soil with lowest recovery being observed in clay soils. Therefore, ddPCR is a promising technology for screening of taeniid eggs from soil samples collected in the environment irrespective of the soil type and the number of eggs. The potential of the ddPCR protocol to detect taeniid egg DNA in spiked soil samples has great practical application for taeniid egg screening in soils from endemic areas. However, when universal primers are used in screening environmental samples, the identity of ddPCR positive samples must be confirmed by sequencing. In addition, more validation studies using species-specific primers and field soil samples is recommended. [ABSTRACT FROM AUTHOR]