Soil Pits Research Articles

Global 137Cs fallout inventories of forest soil across Japan and their consequences half a century later

Japanese forests were exposed to multiple sources of radioactive contamination. To acquire scientific guidance on forest management planning, it is crucial to understand the long-term radiocesium (137Cs) distribution (and redistribution) over time. To obtain robust evidence of the residual global fallout of 137Cs (137Cs-GFO) after a few decades, we determined 137Cs-GFO inventory in forest soil at 1171 soil pits of 316 plots evenly spaced across Japan from 2006 to 2011, shortly before the Fukushima Dai-ichi Nuclear Power Plant accident. The activity concentration measurements were performed using a NaI well-type scintillation counter. The average (±SD) 137Cs-GFO in forest soil (0–30 cm from the surface) of the National Forest Soil Carbon Inventory (NFSCI) sampling plots uniformly extracted from the entire country was estimated to be 2.27 ± 1.73 kBq m−2 (n = 316) as of Oct. 1, 2008. A high nationwide spatial variation was found in 137Cs-GFO, where relatively high 137Cs-GFO was found along the Sea of Japan compared with the total annual precipitation. We also obtained a reconstructed decay-corrected cumulative 137Cs-GFO dataset from the fallout observatories as the initial 137Cs-GFO. The cumulative 137Cs-GFO of fallout observatories averaged 2.47 ± 0.95 kBq m−2 (n = 39) as of Oct. 1, 2008 and displayed spatial variation similar to that in forest soil. To identify whether 137Cs-GFO remains in forest soil across Japan, we examined a general linear mixed-effect model comparing 137Cs-GFO between forest soil and the observatory under normalized annual precipitation and region. The model did not indicate a significant difference, but relatively lesser 137Cs-GFO was found in forest soil, where the least-squares mean of 137Cs-GFO in forest soils was 79.1% of that of the observatory. The variation in 137Cs-GFO in forest soils within NFSCI sampling plots was 1.4 times greater than that among plots. The high spatial variation in 137Cs-GFO within a 0.1-ha plot strongly suggested the redistribution of 137Cs-GFO within the forest catchment. The vertical distribution pattern of 137Cs-GFO across three depth layers indicated that the 137Cs-GFO redistributions were likely attributed to the movements of sediments and mass. Moreover, when extracting soil pits assumed to have the least soil disturbance from the vertical distribution pattern, no significant difference in 137Cs-GFO was observed between forest soil and observatory data. These findings provide important insights into the stability of 137Cs-GFO in the forest ecosystem. Considering the potential hotspot where 137Cs-GFO can accumulate deeper in the soil (>30 cm in depth), most 137Cs-GFO has remained in the forest for decades. Our study offers microscale heterogeneous 137Cs-GFO distribution in forests for ensuring long-term forest management planning necessary for both the long-term migration and local accumulation of 137Cs in forests.

Deformation and Force Analysis of the Pile Foundation System of Deep Foundation Pits in Soil–Rock Combination

This study uses the construction of the Shengli Bridge Station of Qingdao Metro Line 1 as the engineering support for in-depth research of the deformation and mechanical characteristics of the retaining structure of pile-support systems during deep foundation pit excavation under the complex geological conditions of soil–rock combination. This study adopts the finite element software modeling analysis method to simulate the excavation of the foundation pit and the 3D finite element numerical calculation method to calculate the deformation. The modified Mohr–Coulomb model is selected as the constitutive model, and the natural gravity of each layer of soil is considered. The calculated load includes the dead load of structure and soil. The boundary conditions of X, Y, and Z directions at the bottom are fixed constraints, and the top ground is a free boundary. The displacement of soil around the foundation pit and the stress and deformation of retaining piles and crown beams under different working conditions are studied. The deformation law and force mechanism of the supporting structure of the pile-support system are analyzed. The research results reveal the relationship between the synergy of pile-support system and soil deformation, serving as a reference for similar engineering constructions.

Effects of soil substrate on the ecological features of the sand pit-building Antlions Myrmeleon formicarius Linnaeus, 1767 (Neuroptera: Myrmeleontidae) larvae in the Amanos Mountains of Turkey

The hunting behavior of antlion larvae is unique in the insect world and soil characteristics may strongly affect their microhabitat selection. Therefore, the substrate type of sand pit construction is expected to have an important role in their traps. Different types of soil substrates can be inhabited by Myrmeleon formicarius Linnaeus, 1767 larvae. This study was conducted during 2018-2019 June-August in the Amanos Mountains of Turkey to examine assess the relationship between the microhabitat preference of larvae of M. formicarius. In this study, five substrate types were determined as particularly according to their habitat preference. In this study, the preference of fine-grained soils is found more adaptive because of the pits are constructed in these substrates are more functional for longer periods and they are much more successful in trapping their preys than the coarse-grained soil pits. Furthermore, it was found that there is a direct relationship between the pit size and substrate particle structure. Therefore, the detection and selection of microhabitats under more convenient ecological conditions, which increase capture success and elucidate the hunting strategy, may be carried out during strong soil substrate selection for Myrmeleon Linnaeus species. It was concluded that there is no strong relationship between the soil substrate type, pH, and trap diameter.

Geohidrología de un sector de la marisma de Bahía San Blas

La marisma del arroyo Jabalí forma parte de la Reserva Natural Provincial de Uso Múltiple Bahía San Blas y se encuentra ubicada al sudeste de la provincia de Buenos Aires, Argentina. El objetivo del trabajo es analizar los principales procesos geohidrológicos que regulan la química del agua superficial y subterránea de este humedal y su relación con las características geomorfológicas y pedológicas. Para ello se realizó una caracterización geomorfológica en base a la cual se diseñó una red de monitoreo del agua superficial y subterránea. Se construyeron 14 freatímetros a lo largo de 3 transectas perpendiculares al arroyo y se recolectaron muestras de agua en las que se analizó in situ el pH y la conductividad eléctrica y se determinó en laboratorio el contenido de iones mayoritarios. Los datos fueron analizados mediante gráficos de relaciones iónicas y diagramas de clasificación de aguas. A su vez en cada sector estudiado se efectuaron calicatas para la descripción de los perfiles del suelo y características texturales de los sedimentos superficiales. Los resultados obtenidos muestran que tanto la química del agua del canal Jabalí como la subterránea de la marisma son dominantemente cloruradas sódicas, existiendo un enriquecimiento en el contenido iónico asociado a una mayor distancia con respecto a la boca del canal y una posición topográfica más elevada. El principal proceso que condiciona la química del agua subterránea es la disolución de especies minerales formadas en la superficie de los suelos por evaporación del agua de mar y la posterior incorporación en el acuífero por infiltración. Estos procesos se ven favorecidos por el clima semiárido, la menor recurrencia de inundación por posición topográfica elevada, y por la textura fina de los suelos. A su vez, la oxidación de sulfuros pedogenéticos y la consecuente acidificación del medio son propuestos como otros mecanismos que condicionan la química del agua.

An in situ method for quantifying tillage effects on soil structure using multistripe laser triangulation

Soil structure is an important physical property that can be degraded by soil tillage, but methods for quantifying soil structure are both few and time consuming. We developed a method for multistripe laser triangulation (MLT) scanning to quantify soil structure that can be accomplished quickly (15 min of scanning per A horizon exposure) in the field. We scanned three soil pits to a depth of 30 cm in three fields under conventional tillage (CT), three under no-till (NT) and three under perennial grass (PG). For both 0- to 10- and 0- to 30-cm pit depths, we calculated the Dirichlet tessellation area variability (DTAV) for each pit. We found the DTAV from 0- to 10-cm depths was sensitive to tillage type (p = 0.09) and clay percentage (p = 0.06), while the 0- to 30-cm depths were sensitive to neither. Specifically, CT fields had significantly higher 0- to 10-cm DTAVs than NT (p = 0.06) and PG (p = 0.07) fields, while NT and PG were not different from one another (p = 0.99). The information carried by the DTAV may be thought of as the regularity of the Dirichlet tessellation feature areas, which is driven by the regularity of observable soil structural units in the field. The DTAV was not significantly related to soil structure type, grade, or class size described in the field. The DTAV provides an alternative or complement to field soil descriptions that is quick, repeatable, objective, and sensitive to changes in soil structure in response to tillage practice.

Late Quaternary sedimentation dynamics in the Beenchime-Salaatinsky Crater, Northern Yakutia

The Beenchime-Salaatinsky Crater (BSC) is located west of the Olenyok River in Northern Yakutia, ~ 260 km south-west of Tiksi and the Lena Delta. The age and origin (volcanic versus meteoritic) of this crater is poorly understood. The key scientific interest in re-visiting the BSC is the reappraisal of the Quaternary sedimentation dynamics for a better understanding of the sediment history and thickness in the basin. This aides for an assessment, if the site is prospective for a deeper drilling of a Quaternary (or Cenozoic) sediment archive. Soil pits and auger cores from slopes and lowland terrain in the basin were sampled and studied to infer sediment ages and transport dynamics. This also included a thermokarst lake placed in the centre of the basin. Studied properties include grain-size distribution, organic carbon and nitrogen contents (TOC and TN), heavy mineral compositions, δ13C of organic carbon, 14C ages from sediment, δ18O and δD from ground ice and waters, and lake bathymetry from GPR profiling, in addition. We conclude that the crater floor in the BSC is underlain by fluvial/alluvial sediments from the MIS 3 period. Thermokarst lake formation took place during the Holocene Thermal Maximum between 7600 and 6100 cal yr BP. The lake has been shrinking hereafter. Fluvial/alluvial sedimentation along the drainage pattern was active again between 5700 to 1500 cal yr BP, and it was flanked by the accumulation of peaty and organic-rich sediments and the formation of ice-wedge polygons.

Water Level and the Potentials for Wetland Formation and Sustainability in Lower Ogun River Floodplain, Nigeria

Identification, delineation and monitoring of wetlands which requires the understanding and application of their ecological characteristics are critical factors in wetland management and conservation. This study assessed the potentials of wetland formation and sustainability in the lower Ogun river basin by determining the levels of surface and ground water. The study area was divided into 1 km2 grids of 67 units using 0.052 % sampling intensity for the assessments in dry and wet seasons. Monthly water table levels were assessed in 50 cm soil pit while inundation levels were measured during the flooding event using staff gauge. Assessment was carried out for one year during which frequency and periodicity of water table and inundation events were recorded. Results revealed that low water table level ranged from 5 to 45cm of soil depth and occurred between August and September within 6 grids. Water table and surface water was recorded within a period of 2 – 10 weeks during the rainy season. The peak of water levels coincided with the peak of precipitation (> 200 mm) ranging from 30 to 280 cm between September and October while covering 28.75 km2. Conclusively, surface and groundwater levels were recorded during the rainy season having direct variation with the volume of precipitation for a duration that is long enough to support the formation of wetland hydrophytes and hydric soil.
 Keywords: Wetlands; Hydrology; Ground water; Surface water; Inundation; Precipitation

Steroids aid in human decomposition fluid identification in soils of temporary mass graves from World War II

Steroids are widely used for the detection of faecal matter and also – in recent years – for characterising human decomposition in the terrestrial environment. Until now it was not clear whether all commonly used faecal (i.e. 5β-stanols, 5β-stanones and bile acids) and tissue derived steroids (i.e. cholesterol, 5α-cholestanol and 5α-cholestanone) could reveal the presence of human decomposition products in temporary graves. In this study, soil was sampled from three putative mass graves where concentration camp prisoners were temporarily buried for 10 months at the end of World War II (1944 – 45). We hypothesised that soil from the putative temporary mass graves exhibits elevated concentrations of faecal and tissue steroids compared to reference samples, thereby reflecting the former input of human decomposition products. Steroids (Δ5-sterols, 5β-stanols, 5α-stanols, stanones and bile acids) from soil samples from three soil pits suspected to be putative mass graves, as well as reference soil samples, were extracted and analysed with gas chromatography-mass spectrometry (GC–MS). Cholesterol, 5α-cholestanol and 5α-cholestanone were ubiquitously present in all soil pits and reference samples and therefore not indicative for the former input of human decomposition products. Compared to the reference, increased concentrations of selected faecal steroids (coprostanol, 5β-stigmastanol, 5β-cholestanone, lithocholic acid, isolithocholic acid) provided a strong indication of the former input of human decomposition products for one soil pit (pit 2). Additionally, epicoprostanol and isolithocholic acid were unique components for soil pit 2 as they were found neither in the other pits nor in the reference soil. In combination with earlier findings, steroid and bile acid patterns indicate an input of faecal and tissue constituents from former buried bodies in at least one of the three soil pits.

Influence of Anthropic and Topographic Factors on the Physicochemical Properties of the Soil around Temporary Pools in Ferlo, North Senegal

The temporary ponds at Ferlo constitute wetlands whose pastoral activity is of paramount importance in the economy of Senegal. These zones are characterized by a fairly specific microclimate (soft and humid), a shallow depth of the water table, alternating phases of submersion and exudation whose functioning is linked to the soil. Thus the restoration and conservation of these wetlands requires a good knowledge of the soil factors.
 The objective of this study is to compare the physico-chemical parameters of the soil around temporary pools in grazed and ungrazed areas and different topographical units in order to determine their relative similarities.
 The samples taken at different horizons from seven soil pits (P1, P2, P3, P4, P5, P6 and P7) opened in the different morpho-pedological facies of two grazed ponds and one ungrazed pond were analyzed in the laboratory.
 The results obtained show that the soils of Ferlo have a sandy texture and low fertility in the slopes and plateaus. However, they have a balanced texture and average fertility in ponds and ungrazed areas. The factorial analysis made it possible to highlight three distinct soil classes. A class of sandy texture soil with very low chemical fertility comes from the plateau. A class of soil with a balanced texture which is rich in cation and calcium exchange capacity found in the low zones of strong mineralization. A last class rich in chemical element with a silty texture which is found in wooded areas.
 These results thus reveal the predominant influence of anthropic and topographic factors on the evolution and physico-chemical composition of the soil.

Chemical differentiation of recent fine-textured soils on the Caspian Sea coast: A case study in Golestan (Iran) and Dagestan (Russia)

On the recent fine-textured coasts located to the northwest (Russia) and southeast (Iran) of the Caspian Sea at altitudes of 25–26 m below sea level, the difference in elemental composition between two coasts as well as the vertical differentiation of elemental composition (18 chemical elements, 48 samples) in soil pits were studied. The soils of both key sites are close in particle size distribution (the average contents of sand, silt and clay were 10%–30%, 60%–74% and 13%–16%, respectively) and pH (7.4–8.8). Soils on the Iranian coast affected by shallow, highly saline groundwater (the water table is 1.5–2.5 m, solute concentration ~100 g/l) have a uniform vertical distribution of most elements except for As, P and Pb. In soils on the Russian coast with deeper and less saline ground water (2.5 m, ~50 g/l), the total content of the majority of elements (Al, As, Ca, Co, Fe, K, Mn, Ni, P, Pb, Sr, Ti, V and Zn) except for Cr, Cu, Mg and Si changes significantly (P value < 0.05) with depth. The contents of Ni, Si, V and Zn in topsoil, as well as the contents of Al, Cr, Fe, K, Mn, Ni, P, Si, Ti, V and Zn in subsoil, are higher on the Russian coast. The contents of As, Cu, Cl−, SO42− and HCO3− in subsoil are higher on the Iranian coast. Based on weathering indexes (R, PWI, Si/R, Si/Ses and Si/Fe), the recent soils on the Russian coast are significantly more weathered than the soils on the Iranian coast. In Russia, the contents of the potentially toxic elements (As, Cr, Co, Cu, Ni and V) do not exceed the thresholds given in the national soil quality guidelines. In Iran, there is an excess of Co, Cu and Ni according to the national soil quality guidelines for soils with pH > 7. The use of the most stringent international thresholds has shown that the contents of potentially toxic elements on both coasts of Russia and Iran exceed those limits by a factor of 1.5–3.

KURGAN BURIAL GROUND OF THE SCYTHIAN TIME «DERGACHI»

The kurgan mound is located on the edge of the right root bank of the river. Lopan (basin of the Seversky Donets river), near the Dergachi city, Kharkiv region. Now the barrow ground has 32 mounds, although at the beginning of the twentieth century had 60—70 kurgans. The first excavations of the cemetery were carried out in 1903 E. P. Trefiliev who had excavated 10 mounds. The collection of artifacts has not survived up today, and the publication of the results contains brief generalizing characteristics of the burial assemblages. For a long time the exact location of the kurgan burial was unknown, and only recently, during the archaeological exploration, the archaeological site was localized. In 2018—2019 the excavations of the site was resumed. 7 burial mounds were discovered where 6 graves of the Scythian Age were revealed. Burials were not discovered under two mounds, and two one-time burials were found under the one barrow. The obtained data make it possible to reconstruct the funeral rite. Burials were carried out under mounds of small diameter and height. Among the designs of the burial chamber stand out: soil pits, wooden crypts in pits, a pit with shoulders. All burial chambers are directed along the southwest — northeast line, and those buried in them are lied supine, with their heads to the southwest. The grave goods are rather poor, partly due to the robbery of almost all graves. Among the discovered artifacts are the weapons (arrowheads, spear / dart details), jewelry (beads, earrings), household items (knives, awls). A set of signs of the funeral rite suggests that this site is the tribal burial ground of the population who lived in the region at the late 5th—4th centuries BC.

Morphogenetic Diagnostics and Nomenclature of Alluvial-Meadow Soils in the Subtropical Semiarid Area, Floodplain of the Kur River, Azerbaijan

Abstract—The aim of this study was to evaluate morphologic features, diagnostic qualifiers and enhance classification of alluvial-meadow soils in the floodplain of the Kur River within Azerbaijan. For this purpose, several soil pits were placed in the representative test areas and multiple soil samples collected within field campaigns (2014–2015). Based on the field and laboratory test data, the detailed soil maps of the test areas were compiled, and diversity of alluvial-meadow soils was classified as suborders (subtypes): alluvial-meadow primitive; alluvial-meadow layered (flaggy); alluvial-meadow dark and alluvial-meadow irrigated. It was found out that in the floodplains, local soil variability was predominantly attributed to not only alluvial sediments, but also water table, mineralization rate and salt content of underground water as well flood water play an important role. The mineralization of ground water is weak (1.40–3.70 g/L) and the concentration of hydro-carbonates (HCO3) varies from 0.56 to 0.92 g/L. No salinization indication found in the profile of alluvial-meadow primitive and alluvial-meadow layered soils, while weak concentration (solid content = 0.40–0.54%) was found at a depth of 80–150 cm in the alluvial-meadow dark soil. Unlike other subtypes, alluvial-meadow dark soil is characterized with the higher biomass (green weight of top = 41.5 c/h and green weight of underground = 142.3 c/h), high mobility of humus substances with predominance of the 1st fraction of humin (20.0–28.1%) and fulvic acids (14.6–22.3%). The ratio of Ch.a : Cf.a reaches 1.18–1.32. For the alluvial-meadow irrigated soil, the second fraction of humin acid (9.3–10.2%) and total content of humin acid ranges from 45.6 to 50.3%. The ratio of Ch.a : Cf.a is larger (1.37–1.50). Depending on the litho logy of alluvial sediments, the content of SiO2 and R2O3 varies in the ranges of 53.0–57.2 and 9.6–26.0%, respectively. For the alluvial-meadow dark soil, decomposition of alum silicates in alkaline hydrolysis is typical (8.7–9.0). The content of SiO2 and R2O3 varies between 47.8 and 50.6%, and 19.7 and 21.6%, respectively. In the topsoil, of the irrigated soils in associated to washing out the content of Ca and CaO content (12.2–13.1%) increases in deeper horizons.

CHRISTIAN BURIAL GROUNDS OF UPLAND DAGESTAN &#x0D; (BASED ON THE JOINT DAGESTAN-GEORGIAN &#x0D; ARCHEOLOGICAL EXPEDITION)

The paper proposes material of the study of medieval burial grounds of upland Dagestan, obtained during the joint Dagestan-Georgian archeological expedition, which was carried out in Central Upland Dagestan, in the territory of the former Sarir, in 1977-1981. As a result of a comprehensive work, in addition to archeological, architectural, ethnographic and epigraphic monuments, the following medieval burial grounds were studied: Tad-raal, Akhalchinsky, Uradinsky, Khunzakhsky. These burial grounds have been identified with burials dating back to the X-XIV centuries, as well as one burial belonging to the XIX century. Identified medieval burials comprise three types of burial structures: 1) burials in ground pits of rectangular elongated shape; 2) burials in rectangular stone boxes; 3) burials in soil pits of elongated rectangular shape with ledges-shoulders and slabs of horizontal overlaps. The Tad-raal burial of XIX century was made in a wood coffin.The article provides a detailed description of the revealed burial complexes, characterizes the construction of their structures, funeral rite, funeral set and dating of burials. Using the method of comparative analysis of structural features of burial structures and equipment, the dating of the functioning of burial grounds is specified. The considered material allows to conclude on active historical ties of mountain Dagestan with medieval Georgia, as well as the spread of Christianity among the local population. At the same time, it is noted that the expressive and peculiar local culture has preserved the features of the previous epoch, which is reflected in the funeral rite and funeral structures.

Chromium, manganese, nickel, and cobalt mobility and bioavailability from mafic-to-ultramafic mine spoil weathering in western Massachusetts, USA.

Fragmented ultramafic bodies in New England were important mineral resources until the early twentieth century, yet few studies have addressed their potential to release trace metals to terrestrial and aquatic environments. Here, we evaluate the release of four trace metals (Cr, Co, Mn, and Ni) from a historic serpentine-talc "soapstone" quarry in Blandford, MA, USA. Soil pits, sediment and rock samples, and stream water samples were collected from upslope undisturbed areas, within the mine spoils and mine face, and downslope of the mine. In order to provide a bottom-up approach for understanding metal release, careful petrographic analysis, electron-dispersive spectroscopy, and wavelength-dispersive spectroscopy were employed to provide first-order insight into the mineralogy of the deposit and a determination of potential metal-bearing phases. Trace metals were primarily observed in ultramafic sheet silicates, primary Fe-oxides, and interstitial weathering-related sulfates. Bulk rock concentrations were Cr (1550mgkg-1), Co (230mgkg-1), Mn (1100mgkg-1), and Ni (1960mg kg1); Cr, Co, and Ni were elevated relative to the surrounding country rock. However, soils and sediments total concentrations were comparable to background soil concentrations: Cr (119mgkg-1), Co (73mgkg-1), Mn (894mgkg-1), and Ni (65mgkg-1). Moreover, < 0.5% of the total concentrations were bioavailable (0.1M ammonium acetate extraction), implying that metals are present as insoluble forms. However, ~ 20% of the total Cr, Mn, Ni, and Co concentrations were strong acid extractable, suggesting mobilization over the coming decades. Stream water concentrations of Mn and Cr were < 50µg L-1, below concentrations outlined by USEPA drinking water standards, and WHO water guidelines for Ni. These results suggest that transport of Cr, Mn, Ni, and Co from the serpentine-talc as dissolved compounds or sediments is limited by retention within silicate and oxides.

DIGITAL IMAGE PROCESSING FOR EVALUATION OF PASPALUM MILLEGRANA SCHRAD ROOT SYSTEM1

ABSTRACT The characterization of the plant root system is of great importance for the understanding of its contribution to soil shear resistance, constituting an important tool for decision making in soil bioengineering works. The objective of this work was to evaluate the growth and distribution characteristics of the root system of Paspalum millegrana Schrad. grass in Entisol using Digital Imaging Processing (DIP). The data were obtained by opening a soil pit to expose the root system of Paspalum grass up to 1.70 m depth. The profile wall and volumetric ring methods were used to collect quantitative information of the root system. The SAFIRA software and the ArcMAP software belonging to the ArcGIS suite were used for image processing. The profile wall method showed that Paspalum grass has a large volume of roots in the first 0.40 m to 1.30 m soil depth. It was observed that the root length and volume of Paspalum grass reach depths beyond 1.70 m, which is important to increase soil resistance to erosion processes. The profile wall method when compared to the volumetric ring method proved to be more efficient to understand the behavior of the Paspalum grass root system since it enables an assessment of its spatial distribution with better detailing.

When Green Infrastructure Turns Grey: Plant Water Stress as a Consequence of Overdesign in a Tree Trench System

Green infrastructure (GI) systems are often overdesigned. This may be a byproduct of static sizing (e.g., accounting for a design storm’s runoff volume but not exfiltration rates) or may be deliberate (e.g., buffering against performance loss through time). In tree trenches and other GI systems that require stormwater to accumulate in an infiltration bed before it contacts the planting medium, overdesign could reduce plant water availability significantly. This study investigated the hydrological dynamics and water relations of an overdesigned tree trench system and identified factors contributing to, compounding, and mitigating the risk of plant stress. Water in the infiltration bed reached soil pits only once in three years, with that event occurring during a hydrant release. Moreover, minimal water was retained in soil pits during the event due to the hydraulic properties of the soil media. Through a growing season, one of the two tree types frequently experienced water stress, while the other did so only rarely. These contrasting responses can likely be attributed to roots being largely confined to the soil pits vs. reaching a deeper water source, respectively. Results of this study demonstrate that, in systems where soil pits are embedded in infiltration beds, overdesign can raise the storm size required for water to reach the soil media, reducing plant water availability between storms, and ultimately inducing physiological stress.

Investigating Surficial Geologic Controls on Soil Properties, Inorganic Nutrient Uptake, and Northern Hardwood Growth in Western Massachusetts, USA

The influence of glacial geologic materials on soil properties, tree nutrient acquisition, and tree growth rates in New England is not well-constrained. Here, our research investigates the effect of two dominant surficial deposits, glacial till and glaciofluvial deposits, on soils and northern hardwood trees in western Massachusetts. We investigated sixteen paired glaciofluvial and glacial till sites located on the perimeters of glacial lake Hitchcock sediments, which drained 12,400 years ago. At each site, a 12.2-m-radius circular plot was selected, a soil pit was excavated, and all trees within the plot were sampled for foliage and cored with an increment borer. Our analyses found glaciofluvial soils to have significantly higher pH, clay fraction, and water field capacity than glacial till soils. Glaciofluvial soils also had less rock fragments and lower sand content than glacial till soils. We observed significantly higher pseudo-total K, Ca, Mg, and Mn concentrations in glacial till soils, but found similar foliar concentrations for five of the six tree species. Tree cores showed Black Birch, Red Maple, and Red Oak grew 1.3 to 2.1 times faster on glaciofluvial soils. Our study found that glaciofluvial soils, which exhibit greater water retention, less rocks, more fine particles, and higher soil pH than glacial till soils, promote faster growth of Black Birch, Red Maple, and Red Oak. However, the growth of American Beech, White Oak, and Eastern Hemlock was not impacted by surficial deposits, implying adaptation to nutrient limitations, coarser rocky soils, and potential water stress. Thus, the growth of some common tree species is affected by geologic materials, but others are not affected.

Micromorphological features of soils of semidesertic solonetzic complexes under different herbaceous communities with the participation of fodder plant Kochia prostrata (Caspian lowland)

The aim of the study was to research the relationship of chemical and micromorphological properties of soils with the growth ofKochia prostrata. The objects of study were the soils on natural pastures of the North-Western part of the Caspian lowland. It was laid 4 soil pits (soils – light solonetz, solonetzic chestnut) with the maximum penetration depth of the main mass of roots of the studied plants.K. prostratais a very plastic forage species that can grow on soils with a wide range of morphological properties, different salt content and their chemical composition. It is revealed that on the background of almost the same content of humus and high content of exchangeable magnesium micromorphological features represent the different degree of manifestation of primary pedogenic processes – humus accumulation, leaching of soluble salts, gypsum accumulation, carbonate enrichment, solonetzization. Despite the different content of exchangeable sodium, in all soils there are fresh clay or humus-clay illuvial coatings, indicating the manifestation of the modern eluvial-illuvial redistribution of fine matter (lessivage or illimerization).

Bearing Characteristics of Moso Bamboo Micropile‐Composite Soil Nailing System in Soft Soil Areas

Based on the characteristics of moso bamboo including high short‐term strength, stable performance, and ability to provide temporary support for shallow foundation pits in soft soil, the stress characteristics and supporting effects of the ecological composite supporting system have been explored through model tests and numerical calculation analysis of the moso bamboo micropile‐composite soil nailing structure. The results showed that the bamboo pile can effectively control the horizontal deformation of the side wall of the foundation pit and the ground surface settlement, achieving a relatively satisfactory supporting effect. Furthermore, the bamboo pile has visibly bent in middle and lower parts, where the regional shear point is most likely to appear, the axial force of the soil nail is distributed in an oval pattern with a smaller force on both sides and a larger force in the middle part, the maximum axial strain is 447.3 με, and the axial force of the soil nails in each row follows a similar trend. The synergy of piles and soil nails can delay the formation of the slip surface, therefore enhancing the overall bearing capacity of the foundation pit. These results can shed light on the support mechanism and engineering design of bamboo piles in shallow soft soil foundation pits.

Mapping the major soil-landscape resources of the Ethiopian Highlands using random forest

Geospatially explicit information of soil-landscape resources of Ethiopia is lacking or fragmented for much of the country. Recently, massive soil data were collected, however these are limited to properties related to soil fertility and valid for the topsoil only. Understanding the country’s soil-landscape resources, including their qualities and constraints beyond the topsoil, remains key information for systematic and reliable scaling up of evidence-based agricultural best practices including soil fertility management recommendations. The objective of this study was to produce a coherent dataset of the major soil-landscape resources of 30 highland woredas (districts), contributing to the Agricultural Growth Program of the Government of Ethiopia. The study started with an exploratory survey to identify the major (most common) soils occurring across the landscapes followed by a full survey to assess the distribution of the identified major soils. Representative soil profiles were characterised from soil pits and classified as Reference Soil Groups (RSGs), with prefix qualifiers (PQs), according to the World Reference Base for soil resources (WRB). A large number of soil profiles was classified from auger observations. Observed soil classes at both RSG and RSG + PQ level were combined with spatial explanatory variables (covariates), representing the soil forming factors in the landscapes, and their relationships were modelled and validated by random forest. A multitude of tree models was trained using each profile for calibration in approximately two third and cross-validation in approximately one third of the models. Cross-validation showed that RSGs were predicted with a reasonable overall purity of 0.58 and RSGs + PQ were predicted with a purity of 0.48. The most relevant covariate in the models was the Geomorphology and Soils map of Ethiopia at 1: 1 M scale disaggregated into soil-landscape facets. Next models were used to predict soil classes across woredas which resulted in a 250 m resolution raster map of the most probable major soils. This raster map was generalised into a polygon map of major soil-landscape resources. The purity of this final map was estimated to be 0.54 for RSGs and 0.45 for RSGs + PQ. Soil properties relevant for agricultural interpretation, such as depth, drainage, texture, pH, CEC and organic carbon and nutrient contents, were mapped according to the RSGs depicted on the soil-landscape resources map with a RMSE/mean ratio of on average 42%. We conclude that soil expert knowledge and conventional soil-landscape survey combined with random forest modelling results in an attractive hybrid approach. The approach proves cost-effective and sufficiently accurate and can be used to inform scaling up of evidence-based agricultural best practices.