Volume 24 (2021): Edition 1 (May 2021)

Rainwater-induced erosion in green geotechnical infrastructures such as a multilayered landfill cover system (MLCS) is a severe concern in the current era. Although vegetation is a proven measure to control erosion in the MLCS, there are other factors such as infiltration rate which influence the control of the phenomenon. Most of the existing studies are limited to understand influence of vegetation on erosion control or infiltration rate alone. In this study, an attempt is made to incorporate infiltration measurements alongside vegetation cover to understand erosion in surface layer of the MLCS. For this purpose, a pilot MLCS was constructed, and erosion of its surface soil was temporally evaluated through soil loss depth of eroded cover surface under the influence of natural as well as simulated rainfall conditions. Alongside erosion, the amount of vegetated cover was evaluated through photographic image analyses and infiltration rate was measured by mini disk infiltrometer. From the observed results, it is understood that soil erosion and infiltration rate depict a contrasting behaviour with growing vegetation. Antecedent moisture contents were observed to show greater influence on such erosion behaviour which was observed during the testing period. Such studies may be helpful to researchers and practicing engineers for understanding performance of various green geotechnical infrastructures and scheduling the maintenance services to increase the longevity of their layered soil systems.

The objective of the study was to quantify the differences in soil physical indicators between inter-track (uncompacted) zone and track (compacted) zone created by four passages of a wheeled tractor (Landini Globus 70/DBKL Techno). Field studies were carried out on plots of the Vicarello experimental station, Tuscany (43° 27‘ N, 11° 30‘ E). A local average annual precipitation is 678 mm and average annual air temperature is 12.7 °C with absolute extreme values -10 °C and 40 °C. Bulk density, moisture content, water-stable aggregation, and penetration resistance were determined by conventional methods in the 0–0.40 m soil layers. The results showed that the 0.05–0.10 m soil layer, compared to the 0.20–0.25 m and 0.35–0.40 m soil layers, showed a higher degree of compaction by tractor wheels. In this soil layer, significant (at P <0.05 and <0.01) differences between the inter-track and track zone were observed for bulk density (1.18 ±0.10 g.cm⁻³ and 1.35 ±0.10 g.cm-3) and moisture content (24.9 ±2.3% and 27.9 ±2.3% of volume). Passages of tractor even resulted in an insignificant increase of total amounts (from 66.2 ±4.7% to 68.6 ±2.7%) and mean weight-diameters (from 2.29 ±0.30 mm to 2.40 ±0.04 mm) of water-stable aggregates. There were no significant differences in average penetration resistance of the uppermost 0–0.10 m soil layers between the inter-track (0.77 ±0.26 MPa) and track zone (0.64 ±0.12 MPa). Average soil penetration resistance was significantly (P <0.001) higher in the 0–0.40 m layer of the track zone (1.07 ±0.23 MPa) than in that of the inter-track zone (0.76 ±0.11 MPa).

In this field study, under the soil conditions of southern Slovakia (Dolná Streda, sandy Haplic Arenosol), there were quantified the effects of biochar substrates (1. Effeco 50:50; 2. Effeco 33:33:33) in two rates (10 and 20 t.ha⁻¹) applied alone or in combination with mineral fertilization on soil organic matter (SOM) content and crop yields for period of 3 years (2018-2020) but also the linear relationships between SOM and crop yields depending on the application of biochar substrates and its combination with mineral fertilizers. The results showed that the content of soil organic carbon (SOC) increased from 8.5 g.kg⁻¹ in unfertilized control to 13.8 g.kg⁻¹ in Effeco 33:33:33 at 20 t ha⁻¹. However, SOC decreased from 13.6 g.kg⁻¹ in fertilized control to 10.1 g.kg-1 in Effeco 50:50 at 10 t.ha⁻¹. Biochar substrates and their combination with mineral fertilizers did not have a significant effect on changes in labile carbon in the soil. The effect on the crop yields was diametrically different in the first year after the application of biochar substrates compared to the second and third year. In the second and third year, the same trend was observed in the reaction to substrates – including a more robust effect on the increase in crop yields in the third year after the application of biochar substrates and also biochar substrates with mineral fertilizers. The linear relationships between SOC and crop yields were found only in biochar substrates alone treatments.

The study on long-term effects of various crops and fertilization practices on soil eco-chemical state was performed in the complex of Planosols at the Warsaw University of Life Sciences – SGGW experimental station in Skierniewice. The study covered three experiments – Ex-1 (established in 1923; no organic fertilization, cereals as a crop), Ex-2 (established in 1992; farmyard manure application every 4 years, cereals as a crop) and Ex-3 (established in 1975; no organic fertilization, blueberries as a crop). Additionally, each experiment covered three mineral fertilization options, including no fertilization, NPK and CaNPK. Soil samples were taken from A-horizons in 2017 and analysed using standard procedures. The results demonstrate considerable influence of crops and fertilization practices on soil eco-chemical state. Both mineral and organic fertilizers positively affected sorptive capacity as compared to control and modified ionic composition of soil sorption complex. Lower exchangeable acidity and higher sum of exchangeable basis and base saturation were noted in fertilized soils and cereals as a crop as compared to controls. Under blueberries there was observed strong acidification of the soil, in particular in combination with NPK fertilizers, as evidenced by the highest exchangeable acidity, hydrolytic acidity, and the lowest base saturation. Liming partially neutralized acidifying effect of blueberries. Fertilization and crops also strongly influenced buffering capacity of the soils. Extremely low ability to neutralize acidic ions was noted in unfertilized soils, whereas the highest at plots fertilized with Ca. The highest ability to neutralize alkaline ions was typical for NPK fertilized soils under blueberries.

Frequency of flash floods and droughts in the Mediterranean climate zone is expected to rise in the coming years due to change of its climate. The assessment of the climate change impact at a basin scale is essential for developing mitigation and adaptation plans. This study analyses the variation of the hydrologic regime of a small Mediterranean river (the Kalloni river in Lesvos Island, Greece) by the examination of possible future climate change scenarios. The hydrologic response of the basin was simulated based on Hydrologic Modeling System developed by the Hydrologic Engineering Center (HEC-HMS). Weather Generator version 6 from the Long Ashton Research Station (LARS-WG 6.0) was utilized to forecast climate data from 2021 to 2080. These forecasted climate data were then assigned as weather inputs to HEC-HMS to downscale the climate predictions of five large-scale general circulation models (GCMs) for three possible emission scenarios (such as RCP 2.6, RCP 4.5, and RCP 8.5). The alteration of the Kalloni hydrologic regime is evaluated by comparing GCMs based estimates of future streamflow and evapotranspiration with business as usual (BaU) scenario. Variation was noted in seasonal and in annual scale forecasting of long-term average discharges, which show increasing trend in autumn and decreasing in summer and there is observed a general upward trend of actual evapotranspiration losses.

The article aims to present a comparative study of two methods used to determine the particle size distribution of fine and medium coarse soils. These methods are used to determine the grain size distribution curve in practice; however, for different purposes. The classical sedimentation method, based on the Stoke’s sedimentation law (hydrometer, areometric, the Casagrande’s method), standardized for a geotechnical classification of soils was compared with the laser diffraction method on the Mastersizer 3,000 analyser used for soil science purposes. The first comparison on nine samples showed significant differences, especially for larger fractions above 0.01 mm. All measured values of falls from laser diffraction analysis (LDA) showed higher values of all analysed fractions. It was also interesting to follow the trend between the tests for the preparation of conversion factors. The analysis also outlined the direction for further comparison. For the geotechnical use of the LDA, it will be necessary to take into account the sample preparation and processing before analysis.

Soil erosion by wind is the primary land degradation process which affects natural environments and agricultural lands. In agricultural lands, soil erosion by wind mainly results from removing of the finest and most biologically active part of the soil richest in organic matter and nutrients. Repeated exposure to wind erosion can have permanent effects on agricultural soil degradation. Knowing spatial and temporal changes in soil conditions and soil erodibility is essential to understand wind erosion processes. There are many methodologies to predict the susceptibility of landscape to erosion. The more complex is the scheme combining multiple factors, the more accurate the estimate is. There are very few studies on mapping the changes in soil grain size and erodible fraction due to wind erosion. Existing studies only deal with eroded soil units (where particles are removed – deflation) and not the eroded units (areas) to which the eroded particles are wound – accumulated. Prevailing wind direction should also be taken into account when mapping changes in erodible fractions of wind-eroded soils and the nature of the soil (whether soil particles accumulate or deflate). In this study the “historical“ grain size distribution of the soil in three cadastral areas using data from complex soil survey (1968) and year 2018/2019 was analysed. Erodible fraction change was also calculated and compared for both time periods.

The erodible fraction (EF) of soil (soil aggregates and particles <0.84 mm) is one of the basic factors according to which the susceptibility of soil to wind erosion can be assessed. The standard method for determining the EF content is the use of a rotary sieve. Nevertheless, its availability is limited by its price and the fact that it is not mass-produced and is necessary to build the sieve to order. An alternative method of determining the EF content is to use an equation based on knowledge of the content of sand, silt, clay, organic carbon, and calcium carbonate. However, this equation has only been tested for US conditions. Therefore, the research focuses on the validation of the equation for the conditions of the Czech Republic, specifically in the territory of Southern Moravia. The results show that the equation validated for the USA cannot be used to determine the EF content in soils of the Czech Republic. Using the statistical program Unistat©, a new equation was proposed with correlation coefficient R = 0.8238 which means good applicability of the equation for the local soils at least in the area of Southern Moravia.

The process of integration into the European Union (EU) requires from new member states significant efforts; not only harmonizing legislation but also respecting all posed standards. Among numerous issues, wastewater purification represents a significant request. To achieve the goal of discharging good-quality water into natural water bodies as recipients, various methods have been used. The method of constructed wetland (CW) is based on wastewater purification by using wetland plants. The method of CWs shows the best results for small settlements for up to 5,000 inhabitants and can be nicely integrated within the landscape of a plain where waterbodies’ banks are overgrown by wetland plants. Such facilities have been used for decades in the territory of the EU, and only a few have been built in the Republic of Serbia. Since the Republic of Serbia is a candidate country for the EU, there is a strong intention to take action focused upon solving wastewater purification from various sources. Therefore, this paper aims to examine favourable locations for CW installations within the rural area of the South Bačka District. Geographic information system was applied for examination of the basic spatial criteria (distance from the settlement, distance from water bodies, elevation, and land use). These were presented in separate maps and finally in one joint map of favourability for establishing CWs in the vicinity of 35 villages within the District. The obtained results have fulfilled the basic spatial preconditions, but further analyses should be conducted to precisely position the location of each CW concerning land ownership criterion.

The COVID-19 pandemic represented a global phenomenon during 2020. It has spread over most of the countries in the world, leading to the infection of millions of people with a death rate of 2-3% simultaneously causing a serious economic crisis. It resulted in significant pollution reduction, but effects to combat COVID-19 led to an increase of some special pollutants. In such circumstances water can be considered as a cleaning and diluting agent for pollutants, providing hygienic conditions, as well as valuable raw material for the production of a variety of goods necessary for combating COVID-19. On the contrary, water can be viewed as a potential threat in relation to the virus spreading. Within the context of the human water cycle, we have identified possible hotspots related to risks of infection spreading. It may occur when contaminated water is reused (grey and black water), or insufficiently purified water enters the environment, which might interfere with drinking water.