Using of soil quality indicators to assess their production and ecological functions

The project dealt with an evaluation of the soil quality in the Central Bohemian Region in the Czech Republic. The relevant attributes and characteristics were found regarding the soils in this selected area. Based on the data from soil probes, climate characteristics, soil production function and data on the land use, the characteristics, known as soil quality indicators, were selected. Then the soils were sorted into groups which indicated their suitability for the best land use and planning. The characteristics of the soils that contributed the most to the ecosystem services provided by this part of the environment were chosen as the soil quality indicators. In order to find out how the soils are able to provide ecosystem services, two types of approaches were used – the average score and the total amount of points gained. Maps indicating the soil quality were created using the ArcGIS program. At the same time, research on the differences in the quality in two different layers of the soil was carried out. In most cases, there was a decrease in the soil quality with an increasing depth. The results of this project can be used as a basis for a new soil valuation in the Czech Republic.

An overview of a land evaluation in the context of ecosystem services

The environment is changing quickly and it is ever more burdened in connection with the greater needs of human society. This fact has increased efforts to improve the management of land and natural resources and the necessity to evaluate them. Land valuations become more important as the land consumption increases. Soil needs to be evaluated in the whole context of how its quality is affected and the values it provides. The concept of ecosystem services offers this holistic view. This paper defines ecosystem services (ES), the various linkages between soil properties, their functions and benefits, the assessment of soil quality using indicators and then briefly mentions EU environmental assessment methods and terms used in the context of ES. The article also mentions frameworks with which to assess and evaluate the soil quality that can be divided into two groups. The first group is comprised of a framework of indicators that describe the current state of the soil system assessment for evaluating the quality of the agricultural land. This is based on a detailed measurement of the terrain, a statistical analysis of soil databases or processing the status of specific threats to the soil. The second group is comprised of a framework of indicators focused on changes in the soil quality and applied soil management. These frameworks deal with the productivity of the soil in various systems of farming, compare agricultural systems or discuss the advantages of soil biota as indicators of soil quality in detail. Many of the designs of the soil quality indicators focus on the soil management in the context of a single discipline such as agriculture or water pollution. There are concepts for considering the soil quality in regional planning.

The influence of Shewanella oneidensis MR-1 on the transformation of iron oxides and phosphorus in a red soil

In this study, Shewanella oneidensis MR-1, an iron (Fe)-reducing bacterium, was inoculated to a red soil, which was then incubated. Soil samples were taken regularly to analyse the variation of iron oxides and phosphorus (P) fractions. The results showed that the MR-1 inoculation increased the content of the free iron oxides, but decreased the activity of the iron oxides in the soil, and had no significant influence on the amorphous iron oxides. The MR-1 inoculation increased the resin-P and residual-P, decreased the NaHCO₃-extracted inorganic P (NaHCO₃-P_i) and NaOH-extracted inorganic P (NaOH-P_i), but did not significantly influence the diluted HCl-extracted inorganic P (D.HCl-P_i) and concentrated HCl-extracted inorganic P (C.HCl-P_i). The presence of MR-1 influenced the correlation between the free iron oxides and NaOH-P_i. In the CK where deactivated MR-1 was applied, there was a significant positive correlation between the free iron oxides and the NaOH-P_i; in the treatment with the live MR-1 inoculation, there was no correlation between them. In addition, there was a significant positive correlation between the free iron oxides and the C.HCl-P_i, and there was a significant negative correlation between the NaHCO₃-P_i, resin-P, and residual-P. Therefore, the MR-1 inoculation improved the P availability by decreasing the activity of the iron oxides and consequently improved the P use efficiency in the red soil.

Reuse of industrial residues/wastes as a sustainable solution for landfill leachate contaminated groundwater

In order to increase the reuse of wastes and residues, as required by the Waste Framework Directive, the potential use of waste, residue and natural minerals as low-cost permeable reactive barrier (PRB) materials was investigated. The performance of a kitchen waste compost, sepiolite and steel slag was compared with that of volcanic slag, pumice and activated carbon in removing specific contaminants from landfill leachate. The experiments represented that the activated carbon removed 27% of the ammonium (NH4+), 75% of the chemical oxygen demand (COD) and 100% of the phosphate (PO43–), zinc (Zn2+) and nickel (Ni2+) from the landfill leachate. Volcanic slag exhibited removal efficiencies of 50% COD and 100% PO43– and pumice exhibited removal efficiencies of 20% NH4+, 27% Zn2+, 65% COD and 100% PO43–. The reactive materials were also checked for their potential in releasing unwanted constituents and represented different levels of the solute (e.g., PO43–, SO42–, NH4+) release. Among the reactives, sepiolite was found to be the reactive material reflecting a minor release (e.g., Zn2+, Cd2+ and Ni2+), but also delivering removal efficiencies of 40, 50, 65, 95, 97, 98, 98 and 100% for Ni2+, COD, Zn2+, SO42–, Cl–, F–, NH4+ and PO43–, respectively. The results show that the studied materials have the potential as reactives for PRB systems treating high strength contaminant plumes.

Effects of straw return and aeration on oxygen status and redox environment in flooded soil

To study the effects of straw return and aeration of the water layer on oxygen and redox status in the water column and at different depths in paddy field soil, a short-term incubation experiment was conducted with four treatments: (1) no straw return (NS); (2) straw return without aeration (S); (3) straw return and 30 minutes of aeration per day (SO30); and (4) straw return and 90 minutes of aeration per day (SO90). Compared to NS, S decreased dissolved oxygen (DO) and redox potential (ORP) by 23–58% and 47–53 mV, respectively, and increased active reducing substance (ARS) by 21–46% in the water and soil layers. The aeration treatments increased DO and ORP by 25–120% and 11–86 mV, respectively, and reduced ARS by 5–16% compared to S. The results indicated that straw return to paddy fields exacerbated hypoxia and reducing conditions in the soil. SO90 achieved better effects than SO30 in alleviating the negative impact of straw return by supplying more oxygen, but the effects weakened over time and with soil depth.

Soil water dynamics in drained and undrained meadows

Tile drainage belongs to one of the most important meliorative measures in the Czech Republic. It has been hypothesised that it may improve some soil properties which are influenced by the groundwater and their water regime. In the case of meadows, the used management method may also influence the soil properties. In this study, different physical soil properties (particle and bulk density, total soil porosity, maximum capillary water capacity, minimum air capacity, water retention capacity and saturated water content, volumetric water content and matric potential) at depths of 15, 35 or 40 and 60 cm in differently managed meadows (drained versus undrained) located near the village of Železná in the Czech Republic (mildly cold, humid climatic region) were investigated. The drained meadow is used mainly for grazing (extensively) and the undrained meadow is mown twice a year. In addition, the actual evapotranspiration was estimated for the 2018 vegetation season. The selected physical soil properties were significantly (P < 0.05) different between the experimental meadows, especially at depths of 0–28 versus 0–35 cm (particle and bulk density, total soil porosity, maximum capillary water capacity, water retention capacity and saturated water content) and 28–49 versus 35–45 cm (particle density, water retention capacity and saturated water content). In the case of all the studied soil depths, the volumetric water content and matric potential were significantly (P < 0.05) different between the experimental meadows in the years 2016–2019. The actual evapotranspiration was also significantly different (P < 0.05) between the meadows. The obtained differences in the measured soil properties and estimated actual evapotranspiration were probably influenced by the used tile drainage and also by the type of management of the meadow. It is necessary to obtain more research findings with respect to different types of management in the case of drained meadows and also undrained meadows to understand the role of both treatments (tile drainage, management).

Early changes in soil organic carbon following afforestation of former agricultural land

Afforestation of less productive, risky and degraded agricultural land is one of the methods which is recommended for practical agriculture to increase the carbon sequestration. In this study, we have attempted to determine the effect of afforestation of agricultural land (warm, mildly dry climatic region of the Czech Republic) on the soil organic carbon (C_ox) concentrations in the mineral soil. Two soil types (Haplic Chernozem and Haplic Cambisol) were afforested. Both an indirect estimation (loss-on-ignition method) as well as chromsulfuric acid mixture oxidation were used to determine the organic carbon content in the soil samples and the methods were compared. In the case of the Haplic Chernozem, the C_ox concentration at a depth of 0–10 cm after 1–3 years of afforestation with pedunculate oak or Scots pine significantly decreased (P < 0.01 and P < 0.004, respectively) with the stand age. Similar to the case of the Haplic Chernozem, the C_ox concentration in the Haplic Cambisol also significantly decreased in the variants with Scots pine (P < 0.003) or a mixture of forest tree species (P < 0.006); no significant (P > 0.05) decrease was found in the case of a mixture of forest tree species on the Haplic Chernozem or with Douglas fir on the Haplic Cambisol. Significantly higher (P < 0.05) C_ox concentrations were typically found in the case of 1-year-old stands compared to 2-year-old or 3-year-old stands. A higher C_ox loss than the quantity of residues returned to the soils may be the reason the soil C_ox concentration significantly (P < 0.00001 and P < 0.000001) decreased for the control agricultural plots (Haplic Chernozem and Haplic Cambisol). The carbon stock in the upper 10 cm of the 5-year-old stands was higher on the Haplic Chernozem and lower on the Haplic Cambisol compared to the control agricultural plots.

Insights into the development of electrokinetic remediation technology: A bibliometric analysis

Electrokinetic remediation (EKR) is a powerful technique aimed at pollutant removal in soil, sludge, mine tailings, and so on. In the current work, we performed a bibliometric analysis of the research on EKR for the period of 1900–2018 on the basis of the core database of the Science Citation Index Expanded. In addition to a basic analysis of the research characteristics, keywords were analysed for four major participants: USA, China, Spain, and South Korea. The periods of 1990–2001, 2002–2008, and 2009–2018 were studied using the keyword analysis method to gain insights into the development of EKR and predict its future trends. The results revealed that the related research field in the USA was broad during the study periods. Meanwhile, China was interested in fluorine pollution and contamination in red soil. Spain paid close attention to pollution due to agricultural contamination. South Korea focused on radioactive element pollution. The number of papers published over a period of 28 years increased steadily and continued to rise after 2008. The combined techniques of EKR + phytoremediation and EKR + bioremediation were successively utilised by scholars over time, and the latter is expected to demonstrate vitality in the future.

Effects of freeze-thaw on soil properties and water erosion

Freeze-thaw erosion occurs primarily at high latitudes and altitudes. Temperature controlled freeze-thaw events dislodge soil particles and serve as a catalyst for erosion. This review paper provided an overview of the effects of freeze-thaw on soil properties and water erosion. The process of freeze-thaw cycles results in temporary and inconsistent changes in the soil moisture, and affects the soil’s mechanical, physical and chemical properties, such as the soil moisture content, porosity, bulk density, aggregates stability, shear strength and organic matter content and so on. The variation trend and range of the soil properties were related to the soil texture, water content and freeze-thaw degree. Furthermore, the soil erosion was affected by the freeze-thaw processes, as thawing and water erosion reinforce each other. However, research of different experimental conditions on indoor simulations have numerous limitations compared with field experiments. The use of indoor and field experiments to further reveal the freeze-thaw effect on the soil erosion would facilitate improved forecasting.

Determining the effects of the forest stand age on the soil quality index in afforested areas: A case study in the Palandöken Mountains

Afforestation is an essential strategy for erosion control. The objective of this study was to determine the soil quality index (SQI) in established afforested areas of different ages for erosion control in Erzurum, Turkey. Three afforested areas were selected as plots considering their establishment periods: + 40 years old (AA_>40), 10–40 years old (AA_10–40), and less than 10 years old (AA_<10). Forty soil samples were taken in each plot area over the 0–15 and 15–30 cm depths. The soil samples were analysed for the texture, mean weight diameter, aggregate stability, pH, electrical conductivity, total nitrogen, total carbon, and total sulfur contents. These properties were used as the soil quality indicators, whereby the analytic hierarchy process (AHP) and principal component analysis (PCA) were used to establish their relative importance for describing the soil quality. The indicators were scored using the linear score functions of “more is better” and “optimum value”. For determining the SQI, the additive method (SQI_A), the weighted method with AHP (SQI_AHP), and the weighted method with PCA (SQI_PCA) were used. The SQI scores of the plots showed statistically significant differences. In all three methods, the highest SQI value was obtained from the AA_>40 plots.