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Evaluating the liquefaction capacity of saturated loose sandy and clayey soils is an important task to be completed in the course of implementing new construction projects in seismic areas. This article addresses the main characteristics and input parameters of three soil models, including HS small, UBC3D-PLM, and PM4Silt. The behavior of the "soil base–pile foundation–structure" system is examined by using these models to simulate the soil behavior during an earthquake. The results demonstrate the main differences between these models and draw attention to the importance of the choice of a soil model for seismic analysis, particularly when soil liquefaction is considered. [ABSTRACT FROM AUTHOR]

Sesame (Sesamum indicum L.) is an oilseed crop flourishing in marginal lands. It has a high nutritional value because it is rich in protein and fat and has many health benefits. However, the varieties of this crop available in Egypt are very few. Seventeen new sesame lines incurred evaluation in two crop seasons, 2021-2022, for seed yield under eight environments comprising normal and drought conditions in sandy and clay soils. Applying 16 parameters and non-parameters of stability helped select stable and adaptive sesame lines under ideal and drought conditions, with the genotypes arranged in a randomized complete block design with three replicates. Line C5.8 achieved the highest relative productivity in sandy and clay soils and exhibited a good source for breeding programs under drought conditions. Four lines, C1.3, C9.15, C9.6, and C9.20, under eight different environments had higher seed yield than the control. A genetic-environment interaction (GEI) effect on seed productivity occurred in all sources of the combined analysis. The association between seed yield and stability parameters showed the possibility of using a selection index that included some of them to identify sesame genotypes with higher yield and genetic stability. [ABSTRACT FROM AUTHOR]

The piezocone penetration test (CPTu) is a common geotechnical field test to evaluate soil properties. In interpreting the CPTu field measurements, soil drainage conditions are mostly considered completely drained or undrained; however, partial drainage conditions govern for such soils as silts or clayey sand mixtures. Previous studies show that neglecting partial drainage conditions causes incorrect estimation of soil geotechnical parameters. Most studies have been conducted using calibration chambers and centrifuge tests on clayey soils. Due to the complications in modeling the piezocone test, few numerical studies have been performed under partially drained conditions, especially on coarse-grained soils. Among the challenges of numerical modeling of CPTu, one can mention the difficulty of modeling soil structure in large strain mode and soil–water interaction behavior. In this paper, piezocone penetration tests were modeled using the advanced hypoplastic constitutive model and finite-element method. The behavior of Firoozkooh sandy soil under different drainage conditions and relative densities was analyzed. Then, the effect of cone penetration on the surrounding soils was discussed. It was shown that drainage conditions and the soil relative densities significantly affected the trend of variations in excess pore-water pressure (EPWP) generated around the piezocone. [ABSTRACT FROM AUTHOR]

Eucalyptus (Eucalyptus spp.) leads to depletion of nutrients from the soil due to its fast growing nature. Therefore, a pot experiment was conducted to study the effect of zinc (Zn) application on clonal eucalyptus growth, biomass output and its uptake, as well as response of eucalyptus to Zn in soils of three textures. The treatments consisted of eight levels of Zn (0, 5, 10, 15, 20, 25, 30, and 35 mg kg−1 applied through ZnSO4.H2O) in a completely randomized design triplicated in soils of three distinct textures (loamy sand, sandy loam and sandy clay). The plant height, collar diameter, dry weight of shoot and roots, soil plant analysis development (SPAD) readings, Zn concentration and uptake by leaves, stem+branches and roots increased significantly with Zn application. Average dry weight of shoot and roots (31.93 and 15.12 g plant−1, respectively) was significantly highest at 15 mg Zn kg−1 whereas Zn concentration and uptake (18.35 mg kg−1 and 286.2 µg plant−1, respectively) by roots were highest at 20 mg Zn kg−1. The above parameters differed significantly among soils as sandy clay>sandy loam>loamy sand except Zn content and uptake by roots and SPAD values which were highest in sandy loam soil. Loamy sand and sandy loam soil exhibited higher Zn use efficiency, shoot biomass response and uptake response to applied Zn than sandy clay soil. It is concluded to apply 20 mg Zn kg−1 in light soil and 15 mg Zn kg−1 in heavy textured soil for better growth and productivity of eucalyptus. [ABSTRACT FROM AUTHOR]

The agricultural frontier in Brazil advances mainly in areas of sandy soils, where the management of soil fertility is still a challenge, including the practice of liming. Limestone dissolution was investigated under varying doses (0–40 t ha−1) in soil samples with a wide range of textural gradients (5%–74% clay). In view of textural variations and limestone rates, the objective was to generate information regarding pH, the residual liming effect, and exchangeable calcium (Ca) and magnesium (Mg) levels, including under overliming conditions. Throughout the textural gradient, the pH was between 4.2 and 8.5. On more sandy soils (5%–18% clay), overheating (pH > 7) was obtained with ~ 2 t ha−1 of limestone. On clayey soils (37%–74% clay), a similar effect was obtained with ~ 10 t ha−1 of limestone, indicating the marked difference in the acid buffering capacity of these soils. In addition, the equilibrium pH in the context of overliming in sandy soil was higher (8.2) compared with clayey soils (7.8). The residual liming effect was greater in sandy soils due to the lower potential acidity. Regardless of the soil texture, the Ca/Mg ratio increased in the context of overliming. Liming must be carefully applied and requires proper recommendations, especially on sandy soils, avoiding pH ≥ 6.5, a condition that is not suitable for most crops. [ABSTRACT FROM AUTHOR]

The timing of nitrogen fertilizer application in vineyards can determine the amount of nitrogen (N) absorbed, distributed, and accumulated in grapevine organs. The study aimed to evaluate the annual contribution of N from urea, applied at different times in Cabernet Sauvignon, grown in sandy and clayey soil in a subtropical climate. The sandy soil received 21.42 kg N ha−1 and the clayey soil 30 kg N ha−1, both enriched with 3% excess 15N atoms, applied at different times. The N derived from the fertilizer in grapevines, at all times of N application, and in sandy and clayey soil did not exceed 8%, with the highest values being observed in annual organs, especially in the leaves. The application of N marked at the phenological stages of IBB (50% at beginning of budbreak + 50% at full budbreak) enabled greater absorption of N derived from the fertilizer by the vines grown in both sandy and loamy soil. The N present in the annual organs (leaves, berries, stalks, and shoots) and in the perennial organs (stems and canes) of Cabernet Sauvignon grown in sandy and clayey soil was derived in greater percentages from the soil. [ABSTRACT FROM AUTHOR]

Tomato is valued for its nutritional importance and contribution to countries' GDP. Despite the importance of tomatoes, tomato cultivation remains a challenge in some cities, particularly Kumba, Cameroon. This results from a vast knowledge gap for a suitable variety and agronomic management practices. Thus this work was set out to investigate the response of three tomato varieties under organic, foliar, and granular inorganic fertilization at the Kumba I subdivision. This work comprised two factors; variety having three levels (Cobra F1, Rio Grande, and Kiara tomato varieties) and fertilization having four levels (control, NPK 20:10:10 granular fertilizer, Foliar NPK 20:10:10 inorganic fertilizer, and Poultry manure) given twelve treatment combinations replicated three times randomly in a factorial design. Data was collected on soil physicochemical properties, plant growth parameters and fruit yield. The results showed that the variety did not significantly affect soil physicochemical properties, but soil physicochemical properties were significantly affected by fertilization. Poultry manure had the best OC (5.22 %), Ntot (1.73 g/kg), and Pavail (14.63 mg/kg), while K was highest (2.93 meq/100g) in NPK 20:10:10 granular fertilization. Rio grande, in combination with poultry manure, had the best plant growth; plant height (77.3 cm), number of branches (17), number of leaves (197), and leaf area (47.1 cm2). Cobra F1, in combination with foliar NPK 20:10:10 granular and poultry manure, had the best fruit yield; 13.42 tha-1 and 13.56 tha-1, respectively while Kiara variety at the control treatment had the lowest yield (8.36 tha-1). Thus Cobra F1 variety in combination with poultry manure yielded the best result from this study and offers the best option for tomato cultivation in the sandy clay soils of Kumba, Cameroon. [ABSTRACT FROM AUTHOR]

Interactions between adjacent piled-raft foundations may induce additional settlement and cause the tilt of the structure. This case study investigates the long-term performance of a large piled-raft foundation system supporting high and heavy alumina solution storage tanks based on field measurements and three-dimensional (3D) numerical simulations. To properly consider the interactions among rafts, piles, and soils; the elastoplastic behavior of clayey and sandy soils; and the consolidation behavior of soil after construction, a 3D finite-difference code was utilized for the numerical modeling. Two undrained mechanical analyses were conducted to simulate the installation of foundations/tanks and the filling of alumina solution into the tanks, while two coupled hydromechanical analyses were performed to model the period between the two undrained stages and the stage after tank filling, respectively. The predictive capability of the numerical model was checked by comparing the simulation results first with single pile load test data and then with in situ settlement measurements at different locations of the piled-raft foundations. The long-term behavior of the piled-raft foundations was further investigated by analyzing various aspects including the axial force variation along the pile at different locations, the time-settlement relation at monitoring locations, the vertical effective stress increment and displacement of soil, and the differential settlement between monitoring locations. Based on the simulations, the tilt of the platform was mainly due to the superposition of additional stresses near the centerline of the two rows of piled-raft foundations. Finally, parametric studies were conducted to investigate the interactions among the piled-raft foundations at different pile length configurations. The results show that by properly increasing the length of the piles near the centerline of the two rows of piled-raft foundations, the differential settlement of the platforms can be mitigated. [ABSTRACT FROM AUTHOR]

• Long-term expansion rates of 46 Urban Gullies in Kinshasa and Bukavu are quantified. • Gully widening is responsible for most of the gully expansion. • Expansion rates in sandy soils are mainly controlled by land cover and road density. • Expansion rates in clayey soils appear influenced by landslide dynamics. Urban gullies (UGs) are a growing concern in many tropical cities of the Global South. Addressing this new geo-hydrological hazard requires good insights into the rates and controlling factors of this process. Therefore, we investigate the expansion rates of a representative sample of UGs in Kinshasa (n = 17) and Bukavu (n = 29), two contrasting cities in D.R. Congo. We reconstruct long-term (10–17 years) expansion rates, making a distinction between headcut retreat and sidewall widening, and analyse the environmental factors potentially explaining these rates. Total expansion rates varying between 12.6 and 863 m2y-1. Most of this expansion happens through sidewall widening. In Kinshasa, which is mainly characterized by sandy soils, contrasts in expansion rates are mainly correlated to the characteristics of the upslope drainage area of the gullies. Especially the road density and a hypothetical runoff index (combining drainage area, land use and soil characteristics) explain a significant part of the observed variation. In Bukavu, such trends are less apparent. This is likely because the clayey nature of the soils provides more resistance against gullying, resulting in overall smaller and less actives UGs. Furthermore, the already low infiltration rates of these soils probably make the relative impact of urbanization on runoff production smaller. Our results also indicate that UGs located in recent landslides have higher gully expansion rates. The mechanisms behind remain poorly understood. Overall, our work opens promising perspectives to model and predict gully expansion rates in urban settings but may also guide efforts aiming to stabilize UGs. [ABSTRACT FROM AUTHOR]

Eutrophication has led to the widespread occurrence of cyanobacterial blooms. Toxic cyanobacterial blooms with high concentrations of microcystins (MCs) have been identified in the Lalla Takerkoust reservoir in Morocco. The objective of this study was to evaluate the efficiency of the Multi-Soil-Layering (MSL) ecotechnology in removing natural cyanobacterial blooms from the lake. Two MSL pilots were used in rectangular glass tanks (60 × 10 × 70 cm). They consisted of permeable layers (PLs) made of pozzolan and a soil mixture layer (SML) containing local soil, ferrous metal, charcoal and sawdust. The main difference between the two systems was the type of local soil used: sandy soil for MSL1 and clayey soil for MSL2. Both MSL pilots effectively reduced cyanobacterial cell concentrations in the treated water to very low levels (0.09 and 0.001 cells/mL). MSL1 showed a gradual improvement in MC removal from 52 % to 99 %, while MSL2 started higher at 90 % but dropped to 54% before reaching 86%. Both MSL systems significantly reduced organic matter levels (97.2 % for MSL1 and 95.8 % for MSL2). Both MSLs were shown to be effective in removing cyanobacteria, MCs, and organic matter with comparable performance. [Display omitted] • Cyanobacterial cell removal by Multi-Soil-Layering (MSL) ranged from 99 % to 100 % • Greater degradation capacity of MC-LR in MSL1 (sandy soil) and MSL2 (clay soil) • MC-YR variant was most persistent in substrate of both MSL systems • qPCR detected degrading bacteria in both MSL systems • MSL1 had significant abundance of mlrA gene copies and degrading bacteria [ABSTRACT FROM AUTHOR]

The European bioeconomy is steadily driving an industrial, economic, and social growth looking for sustainable biobased feedstocks able to replace fossil-based materials. In this scenario, there is an urgent and increasing need to produce locally industrial crops, with multiple applications and broad suitability to different pedo-climates. Furthermore, the actual EU legislation imposes to produce industrial crops not competing with food ones, and one possibility is to grow them on marginal land. Among others, camelina [ Camelina sativa (L.) Crantz] has been identified as one of the most suitable options for marginal land in Europe, but so far there is a lack of studies conducted in such conditions able to provide reliable production data, on which it will be possible to build plausible business plans. At this scope different field trials have been established in four European countries, i.e., Italy, Greece, Germany, and Poland, in multiple growing seasons from 2018 to 2021, under different types of marginality. In details, in Italy camelina was tested under steep slopes (25% and 15%), in Greece in a soil with low fertility (pH < 5.5) and adverse terrain conditions (steep slope >12%); in Germany in a soil with limitations in rooting, i.e., rooting depth < 30 cm + stoniness > 15%, and in Poland in two sites one with sand > 40%, and the other with clay > 50% of the texture. Camelina was grown with an autumn cycle in Italy and Greece, and with a spring one in Germany and Poland. Camelina production was impacted by the marginal land, seed yield was on average 0.94 Mg DM ha−1, ranging from 0.38 Mg DM ha−1 for camelina sown in spring in Poland in the sandy soil, up to 1.93 Mg DM ha−1 for camelina sown in autumn in Italy on a 15% slope. Camelina completely failed only in one growing season in the clay soil in Poland, in relation to extreme weed pressure, while in all the other situations it was able to produce seed. Seed quality, that was surveyed only in Italy and Poland, was not negatively impacted by marginality, demonstrating its capacity to cope with harsh growing conditions. Growing camelina in southern European marginal land, in autumn sowing, seemed the most conservative and safe strategy to achieve profitable yields. In terms of agronomic management, the most important choices to optimize the crop in marginal land resulted: weed management, N fertilization, and the harvesting phase. • Camelina confirmed to be adapt to European marginal land. • Under marginal land camelina seed yield ranged between 0.38 and 1.93 Mg DM ha-1. • Seed oil content and 1000-seed weight were not negatively impacted by marginality. • Growing camelina in southern European marginal land was the most conservative and safe strategy to achieve profitable yields. [ABSTRACT FROM AUTHOR]

Yield gap analyses are useful to assess and benchmark the productivity of cropping systems. Often such analyses are performed at higher aggregation levels. As a result, these studies lack the detail to explain yield gaps at field level and hence make it difficult to translate findings into precise recommendations to farmers and extensionists. This study provides a detailed approach for yield gap assessments at field level through coupling frequent field monitoring in farmers' fields with crop growth modelling. We used ware potato production in the Netherlands as a case to study yield gaps at field level, as average productivity is high whilst yields are still highly variable among fields, and as ware potato is an important cash crop for farmers. Over two growing seasons, 96 ware potato fields were monitored throughout the growing season on a biweekly basis, taking measurements on soil, crop growth and yield. The crop growth model SWAP-WOFOST was used to simulate potential and water-limited potential yields. Various statistical methods were used to quantify yield gap explaining factors. The average yield gap ranged from 20 to 31% depending on the year and soil type. Among fields, the yield gap ranged from 0 to 51%. On clayey soils, the yield gap was attributed mostly to oxygen stress. On sandy soils, the yield gap was determined mostly by drought stress in 2020, a relatively dry year, and by reducing factors (pests, diseases and poor agronomic practices) in 2021, an average year in terms of precipitation. The type of reducing factors differed per field. Furthermore, we found that earlier planting and later harvesting can increase yields, as Yp is radiation-limited. Overall, there is limited scope to narrow the yield gap as current ware potato production is already close to 80% of the potential yield, which is assumed to be approximately the maximum farmers can attain. However, yield and resource use efficiency gains are to be made for individual fields. Furthermore, we conclude that frequent field monitoring coupled with crop growth modelling is a powerful way to assess yield gap variability and to get detailed insight in the yield gap explaining factors at field level. This study showed that coupling frequent field monitoring with crop growth modelling allows to gain detailed insight in yield gap variability among fields. This method provides detailed information about yield gap explaining factors which can be used to improve yield and resource use efficiency at field level. [Display omitted] • Yield gaps were decomposed at field level for ware potato crops in the Netherlands. • The yield gap ranged from 0 to 53% among individual fields. • The yield gap was attributed mostly to oxygen stress on clayey soils. • The yield gap was attributed mostly to drought stress and reducing factors on sandy soils. • Our method provided detailed insight in the yield gap variability at field level. [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]

Mining operations produce large quantities of tailings that must be handled and stored safely in a technical framework that reconciles economic restrictions and environmental sustainability. Unfortunately, the history of tailings deposits is marked by episodes of catastrophic failures, which is confirmed by the recent tailings dam collapses that occurred in Canada (Mount Polley), Australia (Cadia) and Brazil (Samarco and Brumadinio). Due to this alarming empirical evidence left by the mining industry worldwide, there is international concern and a demand to build these deposits safely from every point of view. In this scenario, the main geotechnical parameter that requires significant attention is the undrained residual shear strength, which is crucial to ensure the physical stability of a tailings dam. The critical state soil mechanic (CSSM) and/or the steady state of deformation provide the conceptual framework for evaluating this strength mobilized by particulate materials. However, despite the fact that these concepts are long established, some important aspects of soil behavior have not been clearly incorporated, which can seriously affect the estimation of the residual undrained shear strength. In this paper the effects of strain rate and reorientation of platy particles in fine-grained soils, the existence of a quasi-steady state (condition of minimum undrained strength) in sandy soils and the limitations of the state parameter are analyzed and discussed. In this context, the main goals are to minimize misjudgments in the estimation of the undrained strength and to introduce an alternative tool, the flow index, I f , to evaluate the susceptibility of the occurrence of flow failure in tailings dams. • The history of tailings deposits is marked by episodes of failures, many of them associated with the occurrence of static liquefaction. • The critical state soil mechanic (steady state of deformation) provides the framework to evaluate static liquefaction. • It is shown that the critical state is more suitable for clayey soils, while the steady state is more useful in sandy soils. • The state parameters do not consider the static shear stress, which in contractive states is responsible for triggering a flow failure. • An alternative state parameter based on the quasi-steady state and the static shear stress is proposed to identify flow failures. [ABSTRACT FROM AUTHOR]