Soil Physical Degradation Research Articles

Groundwater quality deterioration evaluation for irrigation using several indices and geographic information systems: A case study

Groundwater in the Al-Burayhi and Hethran Basin, Taiz, Yemen, it is important source of irrigation water. However, its quality faces threats from both natural and human activities. This study aims to assess the potential deterioration of groundwater for irrigation purposes using several indices and Geographic Information System (GIS) software. Indices, including salinity (electrical conductivity), sodium hazard (Sodium Adsorption Ratio and Permeability Index), combined salinity and sodium hazard index (electrical conductivity and sodium percentage), magnesium hazard index, and chloride content index. The results indicate that 24.14 % of the samples showed high salinity, while 75.86 % showed very high salinity according to the electrical conductivity indices. For sodium hazards, 79.3 % of the samples posed a medium hazard to soil permeability in the long term based on the Permeability Index. Regarding the combined salinity and sodium hazard, 69 % of the samples were of poor quality for irrigation. For magnesium hazards, 55.17 % of the groundwater samples were of poor quality for irrigation. Concerning chloride content, 72.41 % of the samples exceeded the permissible limits according to Yemeni and international standards (350 mg/L). Therefore, using groundwater in the study area for irrigation impedes crop growth and productivity, leads to soil salinization and/or physical degradation due to increased alkalinity, and necessitates costly soil treatments to restore its productivity. Nevertheless, groundwater in the study area can be conditionally used for irrigation by considering all factors affecting the use of low-quality groundwater for irrigation.

FOREST HARVESTING: HOW MACHINE TRAFFIC CAN AFFECT SOIL COMPACTION VARIABILITY

The forestry sector has seen an increase in wood demand in recent years, requiring greater mechanization and sustainability in forestry operations, operational excellence, and productivity of stands. The effect of harvesting machine traffic on the soil alters its physical properties, causing degradation, soil compaction, and reducing the volumes of wood produced by commercial forests. Thus, the objective of the present study was to evaluate the spatial variability of soil physical attributes after harvesting and skidding operations, carried out by a harvester and forwarder respectively, in a commercial eucalyptus plantation. The study was conducted in two areas in the municipalities of Itanagra-BA and Entre Rios-BA. Samples were collected in three layers (0-0.20 m; 0.20–0.40 m; 0.40–0.60 m) and the following items were evaluated: total porosity, bulk density, and soil penetration resistance. Operations performed by the harvester and forwarder altered soil resistance, with a greater effect on sandy loam soils, decreasing their density and porosity. Regarding the number of forwarder passes, the seventh pass generated the peak resistance, altering soil recovery capacity, causing additional compaction. Operational planning, to reduce the effects of compaction in areas most susceptible to physical soil degradation, is essential in the forestry area, especially when moisture values are high, a factor that favors soil compaction and reduces stand productivity.

Traffic induced compaction and physical quality of grassland soil under different soil moisture deficits

Soil compaction is widely recognised as one of the key contributors to soil degradation in Europe. Information is needed for farmers and land managers to guide management decisions and prevent traffic-induced soil compaction. Predicted soil moisture deficit (SMD) from the hybrid SMD model may provide information on when soil conditions are suitable for machinery trafficking. The objective of this study was to investigate the relationship between soil water content and traffic induced soil compaction and if a predicted SMD threshold level could be identified, above which soils can be trafficked without significant soil compaction occurring. The study also evaluated the capacity of selected soil physical indicators such as soil bulk density and water stable aggregates to indicate soil physical degradation across a range of soil water contents. The experiment was carried out on grassland with moderately drained soil, located in Wexford, Ireland. Machinery trafficking of the soil with a tractor equipped with a fully loaded slurry tanker, was assessed in the field across the four seasons of the year. Traffic was imposed at target predicted SMD + 10 mm (relatively dry soil), 0 mm (relatively moist soil), and −10 mm (relatively wet soil). After each traffic event, samples were taken in the middle of the wheel track at three depths (0–10, 10–20 and 20–30 cm) to assess soil bulk density. Water aggregate stability was evaluated at the same three depths following the fourth traffic event. Results showed that when planning field machinery operations, especially repeated trafficking events, soil becomes prone to physical degradation when predicted SMD ≤ 0 mm. Traffic on soil at predicted SMD 0 mm (close to field capacity) lead to compaction after two traffic events. However, when predicted SMD was −10 mm, soil bulk density indicated no significant difference from the non-trafficked soil. When water-stable aggregates were measured on the predicted SMD 0 mm and −10 mm trafficked soils, it indicated physical degradation of soil. Hence, bulk density alone did not give an accurate indication of soil structural quality when soils where trafficked under relatively wet or saturated conditions (SMD −10 mm). These results indicate that avoiding machinery trafficking of grassland soils at predicted SMD ≤ 0 mm will help protect soil physical structure. On soils where multiple machinery operations are likely to occur over the year, trafficking when the predicted SMD > 0 mm is recommended to minimise loss of soil physical quality.

An Approach to the Key Soil Physical Properties for Assessing Soil Compaction Due to Livestock Grazing in Mediterranean Mountain Areas

The selection of key soil physical properties (SPPs) for studying the impact of livestock treading is an unexplored research topic, especially in studies that analyze the influence of livestock management on the degradation process. The objective of this work was to demonstrate that the key SPPs for studying the impact of livestock treading depend on the objectives of the research and the environmental characteristics of the study site. This work used discriminant analysis to establish the most significant SPPs among the following: bulk density (BD), total porosity (P), field capacity (FC), infiltration capacity (IC), and aggregate stability (AS). Results showed that (1) IC and BD are the key properties for identifying the areas affected (bare patch) and unaffected (vegetated patch) by livestock treading, (2) none of the SPPs are significant under increasing stocking rates, and (3) BD is the key property for analyzing livestock impact with increasing stocking rate, using soil calcium carbonate content, slope exposure, and grass cover. We concluded that the relationship between physical soil degradation and stocking rate is not linear because it depends on environmental factors; therefore, to establish the key SPPs, it is necessary to take this fact into account.

Soil Health and Nutrient Management

Soil health and appropriate nutrient management are critical components of sustainable agriculture, influencing crop yield, environmental sustainability, and overall food security. The ability of soil to function as a living ecosystem is referred to as soil health. supports plant and animal life while protecting the environment. It refers to how physical, chemical, and biological activity interact in the soil. Mineral matter, organic matter, water, and air are all critical components of soil health, and each contributes to plant growth. Soil health indicators include physical, chemical, and biological factors that help assess the soil's state. For optimal soil health, these indicators must be balanced.
 However, there are significant issues to address, such as decreased soil organic matter, declining soil fertility due to nutrient deficits, physical soil degradation, and chemical soil degradation caused by excessive chemical use. Practices for sustainable soil management are critical for addressing these concerns. Balanced fertilization, organic matter incorporation, crop rotation, cover cropping, reduced tillage, and precision nutrient delivery are examples of these. Mitigating issues such as nutrient pollution, soil erosion, and soil deterioration is critical to maintaining agriculture's long-term viability.

Impact of spruce deadwood logs on physical properties of a loamy sand Podzol in a steep temperate forest

AbstractThinned steep forests are particularly vulnerable to soil physical degradation. Retaining deadwood logs from thinning operations on the forest floor can potentially mitigate soil physical degradation by modifying its physical properties through increased carbon content in steep regions. We aimed to investigate the effect of spruce deadwood logs from thinning operations on the physical properties of a loamy sand Podzol soil in a steep (30°) temperate spruce forest in Bavaria, Germany. The soil organic carbon (SOC) content was 56% higher under deadwood logs compared to the control areas (p‐value = 0.097). Deadwood logs also increased the soil water repellency by 13% (p‐value = 0.269), while decreasing the soil shear strength by 35% (p‐value = 0.001). Shear strength and water repellency strongly correlated with SOC content, with r = −0.87 and r = 0.86, respectively. Although retaining deadwood logs seems a promising carbon sequestration strategy, it can adversely affect soil shear strength and water repellency and potentially lead to soil degradation. Therefore, the choice to keep deadwood logs on the forest floor may align with specific management goals.

Soil cultivation in the context of climate change and its technical support

Annotation Purpose. Based on the generalization of modern technologies for managing plant nutrition and soil health, to formulate requirements for technical means for soil cultivation in the context of climate change. Methods. Monographic, system analysis, theoretical generalization, abstract and logical. Results. The agrotechnical requirements for the quality of technological operations for soil cultivation in the conditions of climate change to ensure sustainable environmentally responsible production of agricultural products are determined. The analysis of modern technologies for managing plant nutrition and soil health and their technical support is carried out. It has been established that one of the promising areas of greening soil cultivation technologies is vertical tillage, which creates favorable conditions for the accumulation and use of moisture in the soil and reduces the removal of weed seeds from the lower horizons to the surface. The requirements for the technical support of soil cultivation in Ukraine, the use of which in the context of climate change will help to reduce the anthropogenic load on the soil and its physical degradation, are outlined. Conclusions. Mechanical tillage is an important technological operation because in the process of interaction of working bodies with the soil environment, the physical state of the soil changes. The working bodies of tillage tools interacting with the soil should not allow its spraying and compaction in the seedbed should be at least 60 % of soil aggregates with a size of 10 mm to 0.25 mm. In the context of climate change, the paradigm for the development of tillage equipment should be to harmonise the interaction of working tools with the soil, which can be achieved through the automation of their operating modes. To implement energy-saving tillage technologies in the context of climate change, scientists of the Institute of Mechanics and Automatics of Agroindustrial Production of the National Academy of Agrarian Sciences of Ukraine in cooperation with specialists of plant «Krasnyansky JV «AGROMASH» have created and established industrial production of a complex of energy-efficient tillage equipment, including vertical tillage technology. Keywords: climate change, physical soil degradation, soil cultivation, requirements of agricultural technology, ecologization, technical support.

Effects of Land Use on Soil Physical-Hydric Attributes in Two Watersheds in the Southern Amazon, Brazil

Changes in land use can cause degradation of soil physical quality with negative effects on the environment and agricultural production. The effects of different land uses on soil physical-hydric attributes were studied in the Renato River and Caiabi River watersheds in the southern Brazilian Amazon. Three conditions of land use were evaluated: native forest, crops, and pasture in the headwater, middle, and mouth of each watershed. Particle size, particle density, bulk density, total porosity, macroporosity, microporosity, water contents at field capacity and permanent wilting point, and available water capacity in soil were evaluated in three soil layers down to 0.4 m. Data collected were subjected to the Kruskal–Wallis nonparametric test and Pearson’s correlations. Multivariate analyses were also performed using the principal component method. In the Renato watershed, in comparison with native forest, conventional management of pasture and crops caused soil physical degradation, increasing soil density in the surface layer and reducing macroporosity and total porosity. In the Caiabi watershed, converting native forest areas into pasture and crops altered water quality, influencing the water dynamics in the soil, by reducing soil water conductivity. Soil attributes varied by watershed, with texture variations between the headwater and mouth, indicating that changes in soil properties result from both management and the granulometric composition of the soil in different regions of the same watershed. Adoption of crop and pasture conservation practices can improve soil physical attributes in regions bordering agricultural areas in the southern Amazon.

A review on compaction and loosening of agricultural soils

Many soil experts and farmers are very concerned about the hard soil layers of agricultural soils. A layer known as hard soil is created when soil is compacted repeatedly over a long period of time. A type of physical soil degradation known as soil hardening modifies soil structure, restricts air and water penetration, and lessens root encroachment. These effects on the crust of the earth are still not fully understood. Therefore, to solve the worldwide dilemma of future food security, a thorough understanding of the subsurface processes is required. Compaction research must also be taken seriously because climatic conditions are shifting as a result of climate change, opening the door for the creation of novel mechanical tillers that can address compression problems. As a result, the focus of this study is on investigating the type, traits, causes, and effects of soil compaction on agricultural production as well as potential remedies using soil tillage.

Analysis of Physical Characteristics and Soil Degradation Due to Erosion and Rehabilitation Recommendation Based on GIS in Protected Forest Area of Mount Sirimau

Forest areas are designated as protected forests if they function as a provider of clean water reserves, erosion control, city lungs or other functions. Disruption of forest land resources has an impact on changes in the physical properties of the soil and soil degradation due to erosion. Objectives of this study were: 1) to examine the relationship between soil physical properties, 2) to determine soil degradation due to erosion, 3) to examine the relationship between soil physical properties and the level of soil degradation due to erosion, 4) to determine recommendations for land rehabilitation. Research observations were made based on 15 sample areas representing 212 land units. All analyzes were carried out based on Geographic Information Systems (GIS). The physical properties of the soil studied included texture, structure, pore distribution, permeability, particle density and oven dry mass density; whereas soil degradation analysis was based on RUSLE: A=RKLSCP (Renard et al., 1997), and correction of the erosion model A=0.2547RKLSCP (Talakua S.M. and Osok, 2017. The rehabilitation recommendations analyzed were erosion tolerance, potential erosion and CP-maximum. Study results were: 1) The correlation between physical properties was significant (P-value = 0.000*-0.018*) with a positive correlation coefficient (0.163-0.999) and negative one (0.199-0.998); 2) The average erosion rate was: light 3.60 t/ha/year (1425.20 ha), moderate 32.03 t/ha/year (410.28 ha), heavy 108.95 t/ha/year (946 .2 ha), very heavy 426.83 t/ha/year (457.44 ha); 3) There was a significant correlation between the physical properties of the soil and the amount of erosion with a P-value = 0.000*–0.029* with a positive (0.152-0.161) and a negative (0.150-0.151) correlations; 4) Recommendation for rehabilitation are agroforestry patterns combined with tillage and planting of plants according to contour lines on slopes of 0–8%, planting grass in strips, planting low ground cover on high density plantation crops and maintaining secondary and primary forests.

Responses of soil organic carbon cycle to land degradation by isotopically tracing in a typical karst area, southwest China.

The loss of soil organic carbon (SOC) under land degradation threatens crop production and reduces soil fertility and stability, which is more reflected in eco-sensitive environments. However, fewer studies simultaneously compared SOC variations and δ13CSOC compositions under diverse land uses, especially in karst areas. Soil profiles from two agricultural lands and a secondary forest land were selected to analyze SOC contents and their stable isotope composition (δ13CSOC) in a typical karst area located in southwest China to understand the response of the SOC cycle to land degradation. Moreover, the relationships between SOC contents and mean weight diameter (MWD) and soil erodibility (K) factor were comprehensively analyzed for assessing the response of SOC to soil degradation risk. The mean SOC content was found to be the lowest in abandoned cropland (6.91 g/kg), followed by secondary forest land (9.31 g/kg) and grazing shrubland (34.80 g/kg), respectively. Meanwhile, the δ13CSOC values exhibited the following trend: secondary forest land (mean: -23.79‰) ≈abandoned cropland (mean: -23.76‰) >shrubland (mean: -25.33‰). The isotopic tracing results suggested that plant litter was the main contributor to SOC in the secondary forest land. Whereas abundant nitrogen from goat feces enhanced plant productivity and resulted in additional accumulation of SOC in the grazing shrubland. Conversely, long-term cultivation led to the depletion of SOC sequestration by the loss of calcium. In surface soils, the fractionation of δ13CSOC were considerably affected by the decomposition of SOC by soil microorganisms and covered vegetation rather than agricultural influences. The findings indicate that the cycling of SOC and soil stability in the calcareous soil of southwest China are largely regulated by different land uses and the presence of vegetation cover. The depletion of SOC and soil physical degradation pose significant challenges for abandoned cropland, particularly in the karst area, where land degradation is inevitable. Nevertheless, moderate grazing enhances SOC levels, which is beneficial to the land fertility maintenance in the karst region. Therefore, more emphasis should be placed on the cultivation methods and management strategies for abandoned cropland in the karst area.

Controlled traffic farming maintains soil physical functionality in sugarcane fields

The disorderly machinery traffic has been one of the main causes of soil physical degradation in sugarcane fields. In this sense, the adoption of strategies for machinery traffic control has been a viable alternative to reduce the risk of soil compaction and minimize physical restrictions to plant growth. However, the impact of traffic control on soil physical properties is still unknown in sugarcane fields. In this study, we investigated the impacts of machinery traffic control on soil physical properties and functions under contrasting soil textures (clayey and sandy clay), assessed at row and inter-row sugarcane planting positions. Bulk density, soil porosity, soil penetration resistance, the weighted average diameter of aggregates and visual assessment of soil structure (VESS) were measured. In addition, the soil physical quality index (SPQI) was assessed for the following soil functions: support root growth, ability to resist erosion and physical degradation, water supply for plants, edaphic fauna, and its relationship with the exchange of gases between soil and atmosphere. The results revealed that uncontrolled traffic farming increased bulk density, soil penetration resistance, and VESS scores as well as reduced total porosity mainly in the 0–10 cm soil layer. Controlled traffic farming supported soil functions in relation to uncontrolled traffic. Uncontrolled traffic caused a reduction by 12% on the SPQI at row position in both clayey and sandy clay soils, whereas for inter-row position, no difference was observed between the treatments. Controlled traffic in sugarcane fields was able to reduce soil physical degradation induced by agricultural machinery traffic, whose mitigation of compaction occurs mainly at row-position. These results suggest that controlled traffic farming may be a strategy to reduce soil physical restrictions for root growth in sugarcane fields.

A conceptual modelling framework for assessment multiple soil degradation: A case study in the region of Šumadija and Western Serbia

Soil degradation is a global problem and researchers are facing the challenge of assessing the scale, trends, and consequences of contributing processes. With this in mind, this study implemented the new concept of multiple soil degradation indices (MSDI) for the first time in the region of Šumadija and Western Serbia (SWS). This concept enables the simultaneous integration of several environmental components that can act separately or synergistically and offers concrete answers and information on the state and distribution of physical (PSDI), chemical (CSDI) and biological (BSDI) soil degradation. Using several different geospatial-modelled approaches, results indicated that physical degradation was the greatest contributor to soil degradation in the SWS region with an impact of 55%, followed by chemical degradation at 16%, while biological degradation only had a 6% impact. The dominant indicator of physical degradation was the vegetation cover management factor with an impact of approximately 58%, while for chemical degradation it was soil organic matter, with a relative impact of almost 49%. Total microflora and total number of fungi were the most significant biological indicators with an average impact of approximately 43%. In addition, this study indicated that about 59% of the region is currently degraded, with about 44% of it classified as moderately degraded. The results of this study offer new insights into the geospatial dynamics of interactive degradation processes in Serbia and can form the basis for strengthening scientific, expert, and political support when implementing international and national policies concerned with protecting soil from degradation.

IMPACT OF TILLAGE PRACTICES ON PROPERTIES OF SOIL, EVAPOTRANSPIRATION AND PRODUCTIVITY OF COWPEA IN NIGERIA

<p><strong>Background</strong>: Tillage is one of the major threats to soil health which often results into soil physical degradation if not properly managed. Zero tillage is an alternative option from both economic and environmental protection of our soil resources points of view. <strong>Objective. </strong>To evaluate responses of cowpea (<em>Vigna unguiculata</em>) yield and evapotranspiration to different tillage practices.<strong> Methodology</strong>. The study was conducted in Obafemi Awolowo University, Ile-Ife Osun State, Nigeria using a replicated randomized complete block design with treatments consisting of Zero-tillage (ZT), Reduced tillage (RT), Conventional tillage + Mulch (CT + ML) and Conventional tillage (CT). <strong>Results. </strong>Soil penetration resistance (SPR) increased with the degree of soil manipulation during tillage practices. Penetration resistance (PR) across 15-30 cm in 2019 alone resulted in higher PR of 2.26 MPa for RT compared to 0.71, 0.72 and 0.79 MPa for ZT, CT + (ML and CT), respectively, approximately 218 %, 213 % and 186 % greater in RT than ZT, CT + ML and CT respectively. <strong>Implications. </strong>Cowpea production on sandy loam soil can be optimized with Zero tillage. <strong>Conclusion.</strong> Over a period of two years, ZT practice had the highest profit margin of $ 573, among the practices. </p>

Soil Strength and Structural Stability Are Mediated by Soil Organic Matter Composition in Agricultural Expansion Areas of the Brazilian Cerrado Biome

A growing demand for resources has led to the expansion of agricultural areas worldwide. However, land conversion associated with poor soil management might lead to soil physical degradation. We investigated the effects of land conversion on soil physical properties in the Brazilian Cerrado region, under native Cerrado vegetation (NV)—pasture (PA) and NV—cropland (CL) conversion scenarios. Soil physical properties related to compaction, pore size distribution, and structure stability were assessed up to a 30 cm depth. Additionally, carbon levels of soil organic matter fractions (particulate and mineral-associated organic matter) were determined. Our results indicate that the compaction process equivalently reduced the soil porosity in PA and CL. However, soil penetration resistance was higher in PA (~2.5 MPa) than in CL (~1.5 MPa), as well as the stable mean weight diameter of soil aggregates. The highest total and labile organic carbon levels were observed in CL, while the lowest levels of total and labile organic carbon occurred in PA (smaller than in CL). These results suggest that the higher structural stability found in PA was mediated by the predominance of stabilized carbon (a decrease in the proportion of soil labile carbon), causing the gaining of soil strength under negligible soil volume variation (in comparison with CL). Our results suggest that the reduction in the soil porosity by compaction due to PA and CL uses can equivalently reduce macropore space and soil hydraulic functioning, and that soil carbon quality alterations (i.e., labile vs. stabilized fractions) are responsible for the gain in soil strength in long-term degraded PA areas. Future research should focus on understanding the magnitude in which soil organic matter controls soil physical attributes, such as soil strength in these expansion areas, and whether this gain in soil strength limits plant development and compromises productivity in the long term.

Cover crops effects on anisotropy of unsaturated soil hydraulic properties

No tillage (NT) is frequently implemented in simplified agricultural systems, which has negative effects on soil physical quality. Among the suggested practices to preserve the physical fertility of soils under NT are winter cover crops (CC). Soil physical degradation affects the soil pore configuration and therefore it can generate a change in the directionality of the properties that depend on it. The objective of this study was to determine the effect of cover crop incorporation under NT on the soil pore system configuration and on the anisotropy of the unsaturated hydraulic properties in a Typic Argiudoll. The results showed that the inclusion of cover crops modifies the soil pore configuration increasing the structure porosity. The inclusion of CC modifies the anisotropy of unsaturated hydraulic conductivity in the medium saturation region. The pore size distribution behaves as isotropic as expected for a scalar variable.

Variability of Hydraulic Properties and Hydrophobicity in a Coarse-Textured Inceptisol Cultivated with Maize in Central Chile

The O’Higgins Region, located in Central Chile, concentrates 40% of the country’s maize production, mainly under conventional tillage. This has generated soil physical degradation, modifying water movement on it, which varies even in short distances. In this study, we wanted to evaluate the spatial variability of different physical and hydraulic properties in relation to the agricultural use of Inceptisol. The study was conducted on a farm in Central Chile, in a fallow–maize rotation under conventional tillage. Penetration resistance (PR) was measured by using systematic sampling, defining areas of high and low PR, where soil samples were collected in places with frequent crossing of machinery (+M) and places without crossing (−M) and on topsoil and subsoil, establishing four treatments: +M—topsoil, +M—subsoil, −M—topsoil, and −M—subsoil. Organic matter (OM), texture, bulk density (BD), hydraulic conductivity (K), and hydrophobicity (R) were measured. The soil order was Inceptisol with a sandy-loam texture. The PR ranged from 200,000 to 2,000,000 Pa on topsoil and 600,000 to 2,400,000 Pa in subsoil, and the OM content was higher with a low PR. The K varied from 0.6 to 18 cm h−1, being greater in depth, as tillage disturbs the topsoil stabilized during the season. A linear relationship was found between the K and R, explaining differences between high- and low-PR sites. There was an association between Ksat with position (subsoil/topsoil) and PR (high/low) that may allow us to use the PR as a proxy for K.

The Role of the Specific Properties of an Andosol as a Water Reservoir to Improve Pasture Growth and Prevent Soil Physical Degradation in Irrigated Grazing Systems

The Role of the Specific Properties of an Andosol as a Water Reservoir to Improve Pasture Growth and Prevent Soil Physical Degradation in Irrigated Grazing Systems

Multi-Sensor Approach Combined with Pedological Investigations to Understand Site-Specific Variability of Soil Properties and Potentially Toxic Elements (PTEs) Content of an Industrial Contaminated Area

A combination of indirect soil investigation by proximal soil sensors (PSS), based on geophysical (ARP, EMI), physical (Cone Index –CI– by ultrasound penetrometry) and spectrometric (γ-rays) techniques, as well as pedological surveys, was applied in the field to assess the spatial variability of soil pollution and physical degradation in an automobile-battery recycling plant in southern Italy. Five homogeneous zones (HZs) were identified by the PSS and characterized by soil profiles. CI measurements and field analysis showed clear features of physical (i.e., soil compaction, massive structure) degradation. XRF in situ (on profiles) analysis using portable equipment (pXRF) showed Pb, Cd and As concentrations exceeding the contamination thresholds provided by the Italian regulation for industrial land use up to 20 or 100 cm of depth. Hence, a validation procedure, based on pXRF field survey, was applied to the PSS approach used for the HZs identification. High consistency was found between the HZs and the PTEs in the most contaminated areas. Significant negative Pearson correlation coefficients were found between γ-rays dose rate and Pb, Cu, Zn, As and Ni; positive ones were found between γ-rays and autochthonous lithogenic elements (V, Ti, Mn, K, Sr, Nb, Zr, Rb, Th), confirming that higher radionuclide activity correlated with lower pollution levels.

Soil-degradation zoning of Lviv Oblast


 
 
 
 We propose a scheme of soil-degradation zoning of Lviv Oblast, which comprehensively illuminates the problem of degradation and focuses on regional differences in the manifestation and complexity of dominant degradation processes. The highest taxonomic unit of soil-degradation zoning is the soil-degradation country, which in turn is divided into a soil-degradation zone, province, county and district. This classification is based on the landscape features of the study area, the dominant types and kinds of degradation processes. In accordance with the zoning of Lviv Oblast, we have identified the following soil degradation taxa: 2 countries, 3 zones, 5 provinces, 14 counties and 31 districts. The soil-degradation country of the East European Plain unites two soil-degradation zones: Polissia mixed forests and broad-leaved forest zones. The soil-degradation zone (Polissia mixed forests) is best characterized by the processes of deflation and physical degradations. The processes of water erosion and physical degradation of soils dominate within the soil degradation zone (broad-leaved forest zone). Those zones also manifest pyrogenic and chemical degradations. The Carpathian soil-degradation country within Lviv Oblast (the Ukrainian Carpathian zone) is characterized by the distribution of geo-ecological anomalies, mechanical and physical soil degradations. The complex lithological features and geomorphology of the territory in the context of uneven anthropogenic impact determine the intensity of manifestation of degradation. Disturbing the natural stability of the soil cover in the conditions of the mountainous terrain contributes to the activation of the manifestation of degradation processes of geo-ecological anomalies. The problem of soil degradation in Lviv Oblast in the conditions of long-term, intense, and often consumer-orientated agricultural use is considered one of the most urgent tasks of modern agricultural production, soil science, ecology, land management, and environmental protection in general. In addition to arable land, the soils of the Carpathians are degrading due to excessive and often predatory deforestation, recreation and pressure from tourists. As evidenced by numerous scientific publications and our own research, soils are subject to water and wind erosions, overconsolidation and loss of structure, dehumification, depletion, desiccation and aridisation, pyrogenic degradation, contamination by agrochemicals, domestic and industrial wastes, etc. The status of the soils and land resources of the study area is close to critical.