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Biochar, as an organic amendment, could positively change soil properties, especially soil with low organic matter and/or poor structure. Biochar application in sandy soil with low organic matter could be an effective tool for improving hydro-physical parameters of the soil economically and ecologically as well. The effect on bulk density, particle density, porosity, saturated hydraulic conductivity and available water content for plants of two biochar types applied at three different particle sizes in a sandy soil was examined. The results confirmed previous studies, showing decreased bulk density, particle density and saturated hydraulic conductivity and partially increased available water content for plants and porosity. Both biochar type and particle size affected the studied soil hydro-physical parameters. After analysis and comparison of two different types of biochar and three particle sizes, the most effective treatment for sandy soil was proved by the biochar produced from willow with the smallest particle size (

Intense floods represent a challenge to risk management. While they are multivariate in their nature, they are often studied in practice from univariate perspectives. Classical frequency analyses, which establish a relation between the peak flow or volume and the frequency of exceedance, may lead to improper risk estimations and mitigations. Therefore, it is necessary to study floods as multivariate stochastic events having mutually correlated characteristics, such as peak flood flow, corresponding volume and duration. The joint distribution properties of these characteristics play an important role in the assessment of flood risk and reservoir safety evaluation. In addition, the study of flood hydrographs is useful because of the inherent dependencies among their practice-relevant characteristics present on-site and in the regional records. This study aims to provide risk analysts with a consistent multivariate probabilistic framework using a copula-based approach. The framework respects and describes the dependence structures among the flood peaks, volumes, and durations of observed and synthetic control flood hydrographs. The seasonality of flood generation is respected by separate analyses of floods in the summer and winter seasons. A control flood hydrograph is understood as a theoretical/synthetic discharge hydrograph, which is determined by the flood peak with the chosen probability of exceedance, the corresponding volume, and the time duration with the corresponding probability. The framework comprises five steps: 1. Separation of the observed hydrographs, 2. Analysis of the flood characteristics and their dependence, 3. Modelling the marginal distributions, 4. A copula-based approach for modelling joint distributions of the flood peaks, volumes and durations, 5. Construction of synthetic flood hydrographs. The flood risk assessment and reservoir safety evaluation are described by hydrograph analyses and the conditional joint probabilities of the exceedance of the flood volume and duration conditioned on flood peak. The proposed multivariate probabilistic framework was tested and demonstrated based on data from two contrasting catchments in Slovakia. Based on the findings, the study affirms that the trivariate copula-based approach is a practical option for assessing flood risks and for reservoir safety.

The application of biochar is considered to be a beneficial strategy for improving soil ecosystem services. The objectives of this study are to evaluate the differences in the soil erosion of silt loam soil with or without the application of biochar and to compare the impact of the application of biochar on soil erosion for different agricultural practices, namely, bare soil, silage corn, and sown peas. Specifically, the physically-based EROSION 3D model was used to estimate the soil erosion of small plots of sloping agricultural land. In considering various combinations of agricultural practices and rainfalls with different durations and intensities, several scenarios were used to assess the impact of the application of biochar on soil erosion.

Microplastics (particles of plastics

The aim of this work was to analyze and statistically confirm the relationship between the computed daily values of the Effective Precipitation Index (EP365) and the measured moisture content of the topsoil of a research site near Nitra, Slovakia. The statistical analysis (coefficients of determination) confirmed the strong correlation. Subsequently each day’s mean of EP365 (MEP) was used to quantify the long-term deficit or surplus of the soil water supply in the individual years. The daily values of the EP365 index provide a more detailed view of the development of the topsoil’s moisture regime. According to the deviation of EP (DEP) from the 14-year MEP, the most extreme dry periods prevailed during the years 2015, 2017 and 2018. Therefore, the 2012–2018period was evaluated as dry, and the topsoil moisture regime described through the MEP index was compared with the course of the MEP index from the normal (slightly humid) period of the years 2005 – 2011.

Sandy areas occupy a huge amount of land worldwide, but due to their characteristics, they are mostly low in fertility and low in organic matter. Sandy soils have coarse texture, high saturated hydraulic conductivity, low soil organic carbon, and poor aggregate stability and water retention capacity; therefore, it is necessary to add organic additives to them. The objective of this study was to assess the effect of particle size and application rate of biochar (BC) produced under different pyrolysis temperatures on the porosity P, available water content for plants AWC, saturated hydraulic conductivity Ks, and contact angle CA of sandy soil. The results show that an application of BC to sandy soil significantly increased AWC by 76–168%, CA by 252–489%, P by 6–11%, and significantly reduced Ks by 37–90%. Statistical analysis of the effect of three examined factors (BC application rate, particle size, and pyrolysis temperature) revealed that P, AWC, and Ks were affected by all three factors, while CA was affected only by BC application rate and particle size. The statistically significant interaction between the two factors was found for P (temperature × rate and size × rate), AWC (temperature × size), and Ks (size × rate). Statistically significant interaction among the three factors was not found for any hydrophysical parameter. The application of BC to amend sandy soils can be seen as a strategy to mitigate drought conditions and to reduce the amount of irrigation, saving water. Further investigations are needed with regard to the BC application under climate conditions with long hot and dry periods, which may promote soil water repellency. [ABSTRACT FROM AUTHOR]

Low water availability is a significant constraint on global crop production. Exploration is needed regarding plant responses to drought in interaction with biochar, encompassing optimised water use and carbon allocation strategies. The size of the biochar particles also plays an important role, especially in influencing the dynamics of water and plant growth. This study explored the potential impact of biochar treatment on radish growth and drought tolerance. Finer biochar particles lead to the most substantial available water content for plants, increasing at around 30%, while medium and larger fractions increase by about 22% and 16%, respectively, compared to control soil. The chlorophyll fluorescence technique showed improved water management of drought stress at larger fractions of biochar. Our research underscores the potential of biochar treatments for environmental stresses and water scarcity in modern agriculture. [ABSTRACT FROM AUTHOR]

Application of soil modifiers is a widely used practice in agriculture to improve soil quality in support of good agricultural practices. This paper presents an assessment of the effect of zeolite modifiers combined with four soils of Polish and Slovakian origin on their hydrophysical properties. Under laboratory conditions, the characterization of the applied soil additives was carried out along with particle soil analysis. In addition, the prepared soil mixtures were examined using contact angle and saturated hydraulic conductivity. The results suggest that the increase in hydrophobicity occurred mainly after the application of fly ash, and the values for Polish Silty clay soil and Slovak soils: Sandy soil, Silt loam soil, and Silty clay soil compared to the control changed from 73.02° to 96.22°; 8.67° to 24.88°; 29.23° to 33.94° and 19.9° to 26.16° respectively. The increase in hydrophobicity could be explained by the higher CaO content of the high-carbon fly ash compared to the other materials. The parameters of saturated hydraulic conductivity were reduced after the application of all zeolite materials in the case of Polish Silty clay and Slovak Sandy soils. By filling the space between the soil particles, the porous soil additives decreased the hydraulic conductivity. In Slovak soils such as Silty loam soil and Silty clay soil, the opposite effect was observed. The soil additives increased the number and size of pores, which resulted in faster filtration of water and thus an increase in the saturated hydraulic conductivity value. [ABSTRACT FROM AUTHOR]

Forest fires are a common ecological disturbance affecting soil properties and hydrological processes. In this study, we investigated the impact of fire on surface runoff and soil water repellency (SWR) in beech forest through a laboratory experiment. Our main goals were to quantify the severity of SWR caused by low-intensity fires (simulated at 300°C in a muffle furnace) using contact angle measurements with an optical goniometer and to analyze the relationship between heat-induced alterations in SWR and subsequent surface runoff generated by a rainfall simulator in laboratory conditions. The secondary goal of this study was to propose an innovative laboratory approach as an alternative for fire experiments in real forest environments. We collected six monoliths, each with a forest soil surface layer measuring 20 cm x 15 cm x 10 cm, from the ZvolenBudča site. These monoliths were heated at 300°C for 20 minutes in a muffle furnace to simulate the impact of lowintensity wildfires. Subsequently, the burnt monoliths and the Control were exposed to artificial rain from a rainfall simulator, and surface runoff was measured. The results showed a significant increase in surface runoff from the burnt monoliths compared to the Control, indicating the impact of fire-induced changes in soil structure and SWR. Additionally, contact angle measurements using an optical goniometer showed increased SWR in the burnt disturbed samples. The findings of our study underscore the significance of the interplay between fire-induced alterations in SWR and surface runoff. They offer valuable insights into the post-fire hydrological responses and erosion risks in forest ecosystems. These insights could help develop effective strategies to mitigate the environmental impacts of forest fires. [ABSTRACT FROM AUTHOR]