Topsoil Thickness Research Articles

AHP and geospatial technologies for identifying groundwater exploration target regions in Dindigul, southern India

Recent advances in space technology are being widely utilized in resource mapping and management as they provide a high level of accuracy over a short duration and at a lower cost, when compared to traditional methods. Remote sensing and the geographical information system (GIS) play a vital role in collecting and analyzing information used to map resources and earth surface features. For example, anthropogenic activities and climate change affect the natural interaction between the surface and ground water making the monitoring and management of groundwater resources mandatory for future sustainable development. In this study, we attempt to identify the groundwater potential zones in the Dindigul district of Tamil Nadu, India using these emerging technologies. To map regions with groundwater potential, the analytical hierarchical process (AHP) was used to assign weights to all classes in each thematic layer based on groundwater-influencing factors. The sub-features of every parameter were also ranked, using a pairwise comparison method, based on the groundwater-influencing factors and expert knowledge. The parameters selected for the analysis were geology, geomorphology, soil, land-use/land-cover, drainage density, lineament density, slope, rainfall, thickness of top-soil, thickness of fractured zone, thickness of weathered zone, topographic wetness index, roughness and curvature. The weighted overlay analysis method was adopted for all the thematic layers, with technical support from the AHP for assigning weightages. The results were classified into five categories viz., very high, high, moderate, low, and very low potential zones, and used to prepare a groundwater potential map. This map revealed a nuanced distribution of groundwater potential across the district, with varying degrees of potentiality in different regions. Very high potential zones occupy a minimal area (0.07%) but are strategically located in areas characterized by high weathered zone thickness and conducive soil characteristics. High potential zones cover a significant area (22.33%) and are dispersed throughout the district, with specific concentrations in regions featuring highly fractured zones and favorable geological attributes. Moderate potential zones (35.12%) are primarily located in the northeastern part of the study area, while low and very low potential regions cover 19.56% and 22.92% of the study area. The low and very low potential zones appear particularly in hilly terrains, with unfavorable top soil and geological conditions. The validation of the groundwater potential zone (GWPZ) map using the annual average water level data demonstrates a substantial match (60.53%) between the identified groundwater conditions and actual well depths, affirming the reliability and significance of the findings from this study.

Research on Early Warning Method of Plough Layer Thickness of Cultivated Land in Black Soil Driven by Rainfall Events

The thinning of the arable layer causes soil quality degradation, seriously affecting crop growth and even threatening national food security. This article focuses on the problems and needs of poor timeliness, high cost, and inability to dynamically warn about the thinning of the tillage layer in black soil farmland, and conducts research on corresponding warning methods. Based on daily rainfall data, the percentile method is used to calculate the threshold for erosive rainfall event driven warning. Based on erosive rainfall event driven coupling of external soil erosion stress meteorological elements and influencing processes, as well as the connotation of geographic events, the concept definition of geographic events for thinning warning of arable layer thickness is given. The semantic description and discovery method of geographic events are provided, and geographic event driven rules and the technical process of thinning warning of arable layer thickness are formulated. There is a significant correlation between rainfall and topsoil thickness, with a correlation coefficient of 0.83. A soil thickness thinning warning simulation was conducted based on the daily rainfall data of Hailun City, Heilongjiang Province in 2020. On June 14, 2020, when the daily rainfall exceeded the event threshold, an automatic warning for thinning of the plow layer was triggered, achieving a dynamic warning process for thinning of the plow layer. The research results indicate that this method is helpful in solving the problem of thinning warning of the cultivated layer thickness in black soil farmland, and can provide technical support for the quality construction, protection, and management of black soil farmland.

Groundwater Exploration using Geoelectric Technique in Oru-Ijebu, South-West Nigeria

Forty Vertical Electrical Soundings (VES) were carried out using Allied Ohmega resistivity meter with schlumberger configuration in parts of Oru-Ijebu to determine the necessary geoelectrical parameters for delineating the aquiferous zones. Four to five distinct geoelectric layers were delineated from the survey area except for VESORU21 which exhibited six geoelectric layers namely the top soil, clayey sand/laterite, clay and granite gneiss. The first layer serves as the topsoil with high variable resistivity ranging from 11.2Ωm (VESORU7) to 153.8Ωm (VESORU25) with their corresponding thickness of 0.9m to 3.8m respectively. The thickness of the entire top soil of the investigated area ranges from 0.4m to 3.8m. The second layer is composed of sand, clay sand, laterite and partly sandy clay. The resistivity of clay/clayey sand overburden varying from 16.2Ωm with a thickness of 8.7m in VESORU17 and 484.3Ωm with a thickness of 3m VESORU6. The highest resistivity exhibited by the second layer is 974 Ωm in VESORU30 while its lowest resistivity is 21.9Ωm in VESORU34. The resistivity of the third layer which stands as a weathered lithology ranges from 17.2Ωm with a thickness of 10.3m at VESORU7 to 233.2Ωm at VESORU23 whose thickness is indeterminate due to current termination in the field to 196 Ωm; typically diagnostic of clay/clayey sand horizon except beneath VESORU1, VESORU2, VESORU11, VESORU30, VESORU32, VESORU34, and VESORU36 where the inferred lithology is sandstone, fresh basement and partly sandy-clay. The fourth and fifth layers are composed of fresh basement formation notably granite-gneiss rocks with resistivity values ranging from 88.5Ωm VESORU20 to 384Ωm in VESORU15. The maximum aquifer thickness is encountered beneath VESORU25. The weathered layer for the study area is thick enough for groundwater accumulation making it a very prolific one. VESORU1, VESORU2 and VESORU23 are marked by a low groundwater yield due to the dip and the thickness.

Effective dose evaluation for external exposure from surface soil by using resrad-onsite code

An annual effective dose evaluation from Dong Nai surface soil (45 samples) to humans was carried out in this work. ResRad-Onsite software has been applied to estimate the maximum exposure dose by considering different exposure levels across an area of ​​5905.7 km2 with a topsoil thickness of 20 cm. The calculation grid used in ResRad Onsite software is divided in the form of a circle of radius 3, 5, 10, 20, and 30 km, respectively, calculated from the circle center in terms of 16 wind directions. A high-purity germanium detector (HPGe) was used to determine 238U, 232Th, 226Ra, 137Cs, and 40K isotopes. The range activity concentrations of them were found to be 6.46 ÷ 48.11; 13.95 ÷ 58.75; 5.71 ÷ 35.27; 0.15 ÷ 1.23 and 6.7 ÷ 222; mBq/g, respectively. The isotope 239,240Pu was determined by the radiochemical separation method, measured on the alpha spectrometer system, and the calculated value range is 0.009 ÷ 0.073 mBq/g. The activity of 90Sr was determined by separation technique, measured on a low-background alpha/beta total counting system (MPC 9300) with a calculated value range of 0.10 ÷ 0.83 mBq/g. By ResRad-Onsite code, the external effective dose derived from the ground (excluding Radon’s contribution) is calculated to be 170 ÷ 658 µSv/year with an average value is 368.6 µSv/year. The external dose from the soil is 136.5 µSv/year (accounting for 37%). The results showed that the annual radiation dose distribution derived from the ground equivalent to the average of some different regions in the territory of Vietnam and the world. In addition, the external effective dose from the ResRad-Onsite code tended to be about 1.36 times smaller than the practical measured due to the library’s different dose conversion coefficients.

Delineation of Nickel Laterite Deposits in “DCV” Block Southeast Sulawesi Based on Data Analysis of Ground Penetrating Radar (GPR) Method

The need for nickel is very intensive in the development of upstream to downstream industries so that domestic consumption of nickel ore will increase in the coming years, therefore domestic downstream is increasingly being improved. Overcoming the problem of the high demand for nickel in Indonesia can be done by conducting exploration and exploitation to support the downstream of nickel. Exploration of nickel laterite can be accomplished with geophysical methods that aim to obtain subsurface data from nickel laterite deposits. The Ground Penetrating Radar (GPR) geophysical method is one of the non-destructive methods that can be applied to determine the subsurface conditions of nickel laterite deposits based on physical properties in the form of dielectric constants and reflection patterns and amplitude contrasts produced on radargrams. The nickel laterite deposits can be separated into 4 layers based on Ground Penetrating Radar (GPR) data analysis: bedrock, saprolite, limonite, and topsoil. Based on GPR measurements, the average dielectric constant value of topsoil is 6.8 mS/m, the limonite layer is 10.87 mS/m, the saprolite layer is 12.37 mS/m, and bedrock is 7.87 mS/m. It can be seen that the saprolite layer has a high conductivity so that the dielectric constant value is also high, this is influenced by the very high nickel content in this layer. The depth of bedrock in the research area varies from 20 - 40 meters, the thickness of topsoil is dominated in the value range of 3.6 - 5 meters, while the thickness of the laterite layer which is the main target of nickel laterite mining includes saprolite and limonite layers which have varying values of 15 - 40 meters where the distribution of the thickness of this layer is in the eastern and central parts of the research area.

Quantifying links between topsoil depth, plant water use, and yield in a rainfed maize field in the U. S. Midwest

Agricultural production in highly variable soils is a challenge, especially when those soils are shallow. Precision agriculture techniques were developed to improve yields and minimize spatial and interannual variability in profit. In the Central Claypan region of the Midwest United States, many of the precision agriculture techniques were based on the assumption that topsoil depth controlled plant available water, and therefore yield. But this assumption has not been empirically tested. In this study, we use measurements of sap flow installed on maize plants with a gradient in topsoil depth, caused by a claypan layer. We hypothesize that plants with higher water use have higher yield, plants in areas with thicker topsoil have higher water use, and soils in the areas with thicker topsoil have higher soil water content. Sap flow sensors were installed on 5 plants each at three locations with topsoil depths of 19.6 cm (shallow), 21.6 cm (medium), and 30.5 cm (deep) from June – September, 2022. An ANOVA analysis demonstrates that the average total season transpiration at the deep site (279 mm) was significantly larger than at the shallow site (151 mm), while the medium site was in the middle with transpiration not significantly different from either shallow or deep sites (218 mm). At the end of the season, the plants were harvested and total biomass and grain yield were measured. Increase in plant transpiration was significantly related to both increases in biomass and yield. Finally, we measured volumetric soil water content at each location and found higher soil water content at the site with thicker topsoil. Our results demonstrate the link between topsoil depth, soil water content, plant transpiration, and yield. These findings will help improve precision agriculture techniques in areas with highly variable topsoil thickness.

Trends in soil organic matter and topsoil thickness under regenerative practices at the University of Washington student farm.

Conventional methods of agriculture, especially tillage, are often accompanied by soil degradation in the form of erosion and organic matter depletion. Regenerative agricultural methods seek to repair soil ecosystems by building topsoil and soil organic matter (SOM), decreasing reliance on chemical fertilizers and increasing both water retention capacity and the diversity and quantity of soil microbial and fungal communities. The University of Washington (UW) student farm is an organic and regeneratively managed site on the UW Seattle campus. Over the past 20 years the farm gradually expanded so locations on the farm encompass both unimproved topsoil and soils managed regeneratively for periods of 5 to 20 years. This arrangement allows a time-trend analysis of soil development under regenerative methods. Measurements of topsoil thickness (defined as the distance from the ground surface to the base of the soil A horizon) and organic matter content were collected across 14 distinct plots on the farm to quantify trends over time and estimate net change in SOM (and soil organic carbon, or SOC). While SOM content weakly increased by 0.5% per year, topsoil thickness exhibited a significant linear increase of 0.86 cm per year. Over a twenty-year period under the management practices of the UW Farm total organic carbon storage in soils, determined using topsoil thickness, density, and SOC content, increased by between 4 and 14 t ha-1 yr-1. The general increases in topsoil thickness, SOM content, and total soil carbon demonstrate the potential of soil-health-focused practices to help maintain a productive and efficient urban growing space.

Mapping of groundwater potential zones by integrating remote sensing, geophysics, GIS, and AHP in a hard rock terrain

Groundwater is a life-sustaining resource that provides for society's daily water needs, supports industrial development, promotes agricultural activities, and maintains ecological balance. In groundwater resource studies, integrating remote sensing, geophysical data, and GIS tools play a critical role in monitoring, analyzing, and protecting groundwater resources for water resources development and management. This study used a comparative approach since it is less labour-intensive, inexpensive, and efficient. The potential groundwater zones were determined by integrating various data sources such as remote sensing, geophysical, and collateral data and using the Analytic Hierarchy Process (AHP) method. Fifteen different thematic layers, including geology, geomorphology, lineament density, topsoil resistivity, topsoil thickness, weathered zone resistivity, weathered zone thickness, first fractured resistivity, first fractured thickness, second fractured resistivity, second fractured thickness, slope, land use/land cover, drainage density, and rainfall, were mapped in this process. The results show that the northern part of the study area has a relatively higher response of groundwater potential zones than the southern portion. Agricultural areas near surface water bodies and forests, characterized by shallow to moderately weathered pediments and pediplains, exhibit favourable groundwater potential. The study identifies five distinct groundwater potential categories based on area coverage:very low (242.44 km2), low (147.52 km2), medium (241.72 km2), high (26.35 km2), and very high (18.51 km2). The predominant factors influencing the groundwater potentiality are top soil thickness, pediment as well as pediplain (shallow to moderately weathered), lithology (charnockite and fissile hornblende biotite gneiss), slope type (gentle), and rainfall (high). A very good correlation between the groundwater potential zones and the well yield aided in validation of the above findings.

Residual effects of pipeline construction on agricultural soils of the Canadian prairie

AbstractThe return to equivalent capability was evaluated on a >1000 km oil and gas pipeline corridor on the western Canadian prairies. Resource constraints limited this first phase of sampling to soils more likely damaged by disturbance. Three pipelines were selected to span a 55‐year period of construction. Data were collected from four transects established within each of six randomly chosen quarter sections (each 65 hectares) that included reference sites. Laboratory analysis provided data for organic carbon, pH, calcium carbonate equivalent, sodicity, salinity, and particle size distribution. Field procedures were used to obtain data for topsoil thickness, bulk density, aggregate size distribution, and carbonate distribution. The Canadian Land Suitability Rating System was employed to evaluate and compare the land capability (LSRS rating) of three pipelines to that of adjacent reference capability. Pipeline‐reference differences were detected in the topsoil for soil organic carbon (83% of reference), calcium carbonate equivalent (62% higher), and pH (0.4 units higher), and in the subsoil for bulk density (2% higher) and electrical conductivity (a fivefold increase). Carbonates were observed more frequently on the pipelines than on references. Soil organic carbon increased and electrical conductivity decreased with time since construction. The mode of land capability was class 4 on the corridor and class 3 on references. Residual effects remained. Neither soil conservation and reclamation practices, nor natural recovery had yet achieved equivalent capability for the target soil group, representing 17% of the extent of the corridor.

Diagnostic surface horizon vs. conventional surface horizon: The impact of topsoil delineation on the results of topsoil organic carbon density assessment in China

Accurate assessment of the topsoil organic carbon density (TSOCD) is of great importance for the management and conservation of the topsoil organic carbon pools. The conventional surface horizon (CSH) delineation method, which involves specifying a uniform topsoil thickness for all sampling points across a study area, carries the potential risk of inaccurate TSOCD estimation. Chinese soil scientists developed the definition and determination criteria for diagnostic surface horizon (DSH) in Chinese Soil Taxonomy (CST), which were based on the distinctive characteristics of topsoil in China. This study employed a DSH-based topsoil classification method to evaluate the TSOCD of China, based on the findings of the recent national soil survey. Also, TSOCD was calculated for all sample points based on the CSH method, where the thickness of CSH was defined as 5, 10, 15, 20, 30, and 60 cm from the surface. The results showed that DSH-based TSOCD in China ranged from 0.03 to 74.63 kg m−2 with a mean value of 4.34 kg m−2. The standardized topsoil delineation based on the DSH method shows great potential for improving the accuracy of TSOCD assessment and different DSH types exhibited very significant differences in TSOCD (p < 0.01). There was a significant difference between the TSOCD results based on the six CSH delineation thicknesses (p < 0.01). Excessive or insufficient uniform CSH thickness settings may result in over- or underestimation of TSOCD values in comparison to DSH. This study provides evidence that specific uniform thickness delineations are suitable for particular soil types, climatic conditions, and land use patterns, and that the mean TSOCD results derived from these delineations do not significantly differ (p < 0.01) from those based on DSH. The findings of this study have the potential to support the development of more accurate surface horizon delineation methods for managing and making decisions related to topsoil organic carbon pools.

Mapping the soil thickness in the Main Ethiopian Rift using passive seismic data and HVSR, case for Northern water divided between the Ziway-Shala lakes basin and the Awash basin

A passive seismic survey wasconducted in the northern water dividebetween the Ziway-Shala Lakes Basin, Central Main Ethiopian Rift (CMER), and Awash basin. Previous geophysical studies in the same areahad mainly focused on mapping intermediate to deeper Earth geological structures, and little attention given to shallowest layer.In contrast, the study aimed to map these shallow geologic structures of soil layer undulations at this specific location of CMER. A rapid and non-invasive technique was employed, which involve recording three component measurements of ambient seismic noise data. The collected seismic noise data was processed and analyzed using the average of Horizontal to Vertical Spectral Ratio (HVSR) which helpsto determine resonance frequencies of the survey stations. After frequency estimatesweremadefor each station, corresponding depth estimates were obtained using the method of Nakamura.The point depth to the shallowest layer was determined for each siteand these depth valueswere gridded and mapped to show subsurface topographic undulations or thickness of topsoil cover.The result showed that the shallowest bedrock layer wasthickening northwards, toward the Awash basin.

Comparison of rehabilitation treatments on mechanically reconstructed soils following strip coal mining activities: effects on soil properties

A rainfed rehabilitation trial on mechanically reconstructed soil, following strip coal mining, was laid out in the Mpumalanga Province of South Africa. It was used to evaluate seven rehabilitation treatments with four different depths of topsoil on coal spoil over three experimental seasons. A strip plot design was used to apply the treatments. The test crop was a grass mixture comprising of annual and perennial species. Trial measurements included soil physical, chemical and microbiological measurements, as well as growth and composition of the grass stand. Monthly rainfall was very variable with annual totals below the long-term values. Statistical significance was proved for most measurements. Relatively high soil bulk densities, stratified with depth, were measured, indicating undesirable soil compaction. Infiltration rates increased while soil strength decreased dramatically with increased topsoil thickness. A reciprocal interaction of profile water content and biomass yield was observed with water content decreasing as biomass yield increased. A large variation in soil chemical properties was observed as a function of the treatments. This study highlights the fact that the monitoring of soil and plant properties should be a prerequisite in any rehabilitation study. Similar trials on different soils and in different rainfall regions should be considered to expand our knowledge of the impacts of different soil treatments in a range of ecosystems.

ANALISIS PEMBENTUKAN TANAH DARI BATUAN PENUTUP OVERBURDEN PADA AREA REKLAMASI PT BORNEO INDOBARA GUNA MENDUKUNG KEBERHASILAN REKLAMASI SECARA BERKELANJUTAN

This study aims to analyze the process of soil formation on overburden material in the reclamation area in 2013 (9 years), 2015 (7 years), and 2018 (4 years) to support the success of sustainable reclamation, and analyze the relationship between planting age, morphology and climate conditions in the study area that can affect the process of soil formation in the overburden. The research was conducted at a coal mining company located in Tanah Bumbu Regency, South Kalimantan Province. The research method used was descriptive quantitative. Data collection was done by making a test trench and taking soil profile data which includes topsoil thickness, intermediate layer, and overburden. Soil texture, soil color, and data on roots that penetrated the soil were also recorded and analyzed. The results of the test trench analysis showed that the process of soil formation in the overburden began to occur in the reclamation area in the 9th year (2013). The indicator found lateral roots in the soil layer at a depth of 40-60 cm which is an overburden layer with gray soil color. The correlation test showed a strong relationship between soil acidity (pH) and the year of planting (r2 = 0,74). The relationship between organic C elements and the year of planting (r2 = 0,68). The element N in the soil has a very strong relationship with the year of planting (r2 = 0,92). The next element was P2O5 in the soil having a moderate relationship (r2 = 0,46) and K2O elements had a strong relationship (r2 = 0,75). The results of soil chemical analysis and also soil texture showed that the soil fertility status at the study site was in low condition. This study concluded that the process of soil formation in overburden was found in the planting year area of 2013 or year 9, with indicators such as the appearance of roots in the overburden area at a depth of 20 - 40 cm, whereas in 2015 and 2018 no roots were found in the overburden. Climatic and morphological conditions accelerated the process of soil formation in the overburden because this very wet condition accelerated the process of leaching nutrients to the surface layer of the reclamation area. The process of weathering in the soil, especially in overburden, will cause plant roots to enter the overburden layer by bringing nutrients produced by trees, undergrowth, and litter to the research area.

Integrated hydrogeophysical and GIS based demarcation of groundwater potential and vulnerability zones in a hard rock and sedimentary terrain of Southern India

This research has identified the groundwater potential and vulnerability zones in Tiruchirappalli district of Tamil Nadu, India. The Schlumberger electrode array has been used to conduct vertical electrical sounding (VES) at 95 sites with a maximum electrode spacing of 150 m. The study area comprises of hard rock and sedimentary formations. Geographical Information System (GIS) has been used to integrate the geoelectrical data and to prepare spatial variation maps for various parameters. Finally, groundwater potential and vulnerability zones have been demarcated, and these outputs have been validated using water level and nitrate data, respectively. The Dar-Zarrouk parameters such as longitudinal conductance (S), transverse unit resistance (T), and aquifer anisotropy (λ) have been used along with the spatial variation of resistivity and aquifer thickness to find out groundwater potential areas with the support of GIS. The thickness of topsoil, weathered zone and fractured zone are not uniform in the research area. Top soil plus weathered zone acts as a water table (phreatic) aquifer, which extends up to 38 m from the surface. Fractured zone extends up to 45 m, which acts as a kind of confined/semi-confined aquifer. Open and bore wells have been constructed to tap groundwater from the unconfined (water table) and confined/semi-confined aquifers, respectively. High to very high groundwater potential areas are associated with low resistivity, high thickness, low longitudinal conductance, high transverse unit resistance and high aquifer anisotropy areas. Very high groundwater potential areas are mostly confined to flood plain (alluvium) deposits in the central portion of the study area. High potential areas are noticed in the northern part, whereas low potential areas are noticed in the southern part. The areas with high longitudinal conductance indicate low permeable zones with less possibility of external pollution. Since agriculture is an important activity in the study region, this work will be useful to provide water supply for irrigation as well as for domestic needs.

Зависимость отражательных свойств агропочв в сверхширокой полосе частот от типа, степени шероховатости поверхности и профилей влажности агропочв

In this article, the impact of volumetric moisture from 0% to 40% (vertical moisture profiles), dry bulk density from 0.4 to 1.8 g/cm3, clay content from 0.15 to 0.55 g/g (agrosoil type), standard deviations heights of surface roughness from 0 to 4 cm of soil on the variations of reflection coefficient in the ultra-wide frequency band from 100-400 MHz to 1.26-2.4 GHz were investigated. The reflection coefficient was calculated for a smooth and rough soil surface. Mironov's two-relaxation dielectric model was used (input parameters: dry bulk density, clay content, volumetric moisture, frequency of electromagnetic wave) to calculating the reflection coefficient. It is shown that the reflection coefficient is an ambiguous function of the clay content and the dry bulk density; the error in retrieving high values of soil moisture can be 5 times higher than for dry soils. In relation to the clay content and the dry bulk density, the soil roughness is the dominant parameter, which uncertainty, significantly effects on the error of soil moisture retrieving. For the considered various vertical profiles of soil moisture, it is shown that the effective thickness of topsoil, which forms the reflection coefficient, does not exceed 2 cm at a sensing frequency above 1 GHz. When the volumetric moisture content of soil surface is more than 28%, the reflection coefficient in the frequency range from 433 MHz to 1.26 GHz does not depend on the vertical distribution of moisture in soil. The conducted studies establish quantitative limitations on the accuracy of soil moisture retrieval for a given error in the initial parameters of the model: the clay content, the dry bulk density, soil surface roughness, which should be taken into account when developing algorithms for remote sensing of agrosoil moisture.

Geoelectrical Method to Determine Andesite Rock Potential in Kepuh, Ciwandan District, Cilegon City

The Kepuh area has abundant andesite rock resources. These rocks can be used as building materials and for other infrastructure. Based on this, it is necessary to research the potential of andesite resources. The tools used for this research are a resistivity meter, meter, current and potential wires, electrodes, hammer, battery, a global positioning system (GPS), handy talky, laptop and software (IP2win). The research applies the geoelectric method, which measures rock resistivity values. This geoelectric investigation uses the Schlumberger array. The advantages of the Schlumberger array are that fewer electrodes need to be moved for each sounding, and the cable length for the potential electrodes is shorter. Schlumberger soundings generally have better resolution, greater probing depth, and less time-consuming field deployment. The data obtained from the measurements were processed using IP2win software by entering the magnitude of the current, the value of the potential difference, and the electrode. The results of geoelectrical interpretation, the rocks found in the research area are topsoil, tuff, and andesite lava. The resistivity value of the topsoil in the study area mostly varies from 26.3 – 116 ohms – meters, tuff has resistivity values range of 18.8 – 84.2 ohms – meters, and Andesite lava has a resistivity range of 128 - 570 ohms – meters. The average thickness of topsoil is 1.4 meters, the average thickness of tuff is 25.9 meters, and the average thickness of andesite lava is 42.6 meters. Based on the average thickness, andesite rock can be the main commodity.

Are Iron Tailings Suitable for Constructing the Soil Profile Configuration of Reclaimed Farmland? A Soil Quality Evaluation Based on Chronosequences.

Iron tailings used as soil substitute materials to construct reclaimed farmland soil can effectively realize the large-scale resource utilization of iron tailings and reduce environmental risks. It is vital to understand the mechanisms affecting reclaimed soil quality and determine the appropriate pattern for reclamation with iron tailings. Thus, a soil quality index (SQI) was developed to evaluate the soil quality of reclaimed farmland with iron tailings in a semi-arid region. Soil samples were collected from two reclamation measures (20 cm subsoil + 20 cm iron tailings + 30 cm topsoil and 20 cm subsoil + 20 cm iron tailings + 50 cm topsoil) with reclamation years of 3 (R3), 5 (R5), and 10 (R10) at three soil depths (0–10, 10–20, and 20–30 cm) to measure 13 soil physicochemical properties in western Liaoning, China. Adjacent normal farmland (NF) acted as a reference. Results indicated that iron tailings were suitable for constructing the soil profile configuration of reclaimed farmland. SQI of reclaimed soil increased with the reclamation year, but it has not reached the NF level after 3 years, while it was better than NF after 5 years. The nutrient content of reclaimed soil increased with the reclamation year, but it still did not reach the NF level after 10 years. SQI of R10 (with 50 cm topsoil) was also better than NF but slightly lower than R5 (with 30 cm topsoil). For the semi-arid region with sticky soil texture, the topsoil thickness of reclamation was not the thicker the better, and 30 cm topsoil covered on iron tailings in western Liaoning could achieve a better reclamation effect than 50 cm.

The growth of Paraserianthes falcataria at three different plant ages and soil thickness classes on reclamation sites of post-coal mining areas in East Kalimantan, Indonesia

Abstract. Mulyadi, Ruhiyat D, Aipassa MI, Hardwinanto S. 2022. The growth of Paraserianthes falcataria at three different plant ages and soil thickness classes on reclamation sites of post-coal mining areas in East Kalimantan, Indonesia. Biodiversitas 23: 1930-1937. Sengon (Paraserianthes falcataria (L.) Nielsen syn. Falcataria moluccana (Miq.) Barneby &amp; J.W. Grimes) is a fast-growing species commonly used for reclamation of post-coal mining areas in East Kalimantan. The study aimed to determine the impact of different thicknesses of topsoil applied at some reclamation sites after coal mining activities on the growth of P. falcataria. Three coal mining companies were chosen as study areas, i.e., PT Bukit Baiduri Energi (BBE), PT. Mahakam Sumber Jaya (MSJ), and PT. Kaltim Prima Coal (KPC). The regolith soil layer at the reclamation site had three thickness classes (0-10 cm, 0-30 cm, 0-100 cm), and the P. falcataria growing on reclamation had three ages, i.e.,&lt; 2 yrs old (initial growth phase), 2-5 yrs old (tending phase), and &gt; 5 yrs old (independent growth phase). The number of surviving plants, plant height, and plant stem’s diameter were recorded, and the data were analyzed using ANOVA and the least significant difference at 5% level. The results showed that no significant difference in the number of trees among different ages of P. falcataria plantation was found at MSJ. In contrast, at BBE and KPC the number of surviving trees decreased significantly with the increasing plant age. The growth of the plant (height, diameter) increased significantly along with plant age in all sites. The interaction between the top soiling thickness factor and plant age factor produced no different result in plant growth except for plant height at BBE. The P. falcataria plants had not been able to lower the surface soil density in the land reclamation area.

Soil water repellence increased early wheat growth and nutrient uptake

PurposeSoil water repellence causes uneven soil wetting which can constrain dryland crop and pasture establishment and yield. The same processes are likely to affect nutrient availability from soil and fertiliser, but the effects of repellence on crop growth and nutrition per se have seldom been reported. Here, we investigated early wheat (Triticum aestivum cv. Mace) growth and nutrient uptake responses to repellence.MethodsWheat was furrow-sown in severely repellent sandy loam soil (with a wettable furrow base to allow for germination) or completely wettable soil, under uniform plant density and variable topsoil thickness (20 or 100 mm) and fertiliser band placement (below or away from the seed). Tiller number, shoot dry matter, shoot N concentration, total nutrient uptake, and root length density (RLD) were determined.ResultsContrary to expectations, repellence significantly increased tiller number (by up to 2 tillers per plant), shoot dry matter (by 82%), shoot N concentration (by 0.3% N), and total nutrient uptake (by 87%) at 51 days after sowing, regardless of topsoil thickness and fertiliser placement. In the furrow, RLD of repellent treatments was also nearly double that in wettable treatments when fertiliser was banded below the seed. Results suggest that preferential soil wetting of the furrow in repellent treatments favoured plant nutrient uptake under regular but low water supply.ConclusionWe conclude that for water-repellent soils with limited water supply, water harvesting techniques such as furrow sowing and banding wetting agents could boost water and nutrient uptake and early crop growth.

Changes in the profile properties and chemical weathering characteristics of cultivated soils affected by anthropic activities

The study of the pedogenic process in response to natural evolution, gradual anthropogenic shifts and engineering upheavals is of great significance for understanding, utilizing and transforming nature in the future. Although scholars have considered anthropic activities to be an important factor affecting pedogenesis, research on how and how much anthropic activities influence the soil-forming process is scant. This paper was conducted to analyse pedogenic characteristics dominated by anthropic activities. In this study, the parent materials and soils undergoing natural evolution (NE), tillage perturbation (TP) and engineering perturbation (EP) were selected as research objects. The genetic characteristics of soils undergoing NE, TP and EP are investigated mainly from three aspects: soil profile macromorphological characteristics, soil physical and chemical properties and chemical weathering characteristics. The results indicated that the influence of anthropic activities (TP and EP) on the process of pedogenesis is complicated. First, compared with NE, TP decreases the thickness of topsoil from 22.2 to 21.2 cm, while EP increases the thickness of topsoil from 22.2 to 23.2 cm, and EP causes the soil to have a high profile development index. Second, compared with TP, EP can improve bulk density (BD), soil organic carbon (SOC), total nitrogen (TN) and cation exchange capacity (CEC), Finally, the chemical weathering intensity differed among NE, TP and EP and followed the order of TP > NE > EP. Therefore, in the future, the genetic characteristics of soils dominated by anthropic activities should be considered. This will help us systematically understand the genesis and evolutionary characteristics of soil and lay a foundation for further perfecting the diagnostic horizon and diagnostic characteristics of the Soil Taxonomy and World Reference Base.