Natural landscapes in the Mediterranean ecosystem have experienced extensive changes over the last two centuries due to wildfire activity. Resulting interactions between climatic warming, vegetation species, soil natural, and meteorological condition before and after a wildfire create substantial abrupt landscape alterations. This study investigates the evolution (2 days, 3, 6, 9, and 12 months after a fire) of topsoil (0–5 cm) chemical properties in burned Cambisols (Zadar County, Croatia) with respect to different wildfire severities (HS—high severity, MS—medium severity, C—unburned) and vegetation species (Quercus pubescens Willd. and Juniperus communis L.). Soil pH, electrical conductivity (EC), calcium carbonates (CaCO₃), total organic carbon (TOC), total nitrogen (TN), total sulphur (TS), copper (Cu) and zinc (Zn) were significantly higher in HS than in MS and C. Total soil potassium (TK), Fe and Ni were significantly higher in C than in HS. The increase of TOC and TN was more pronounced in Quercus p. than Juniperus c., especially in the first three months. Soil pH, EC, CaCO₃, TOC, TN, and TS were most affected by wildfire severity. The distinction between C, MS and HS categories was less visible 9 and 12 months post-fire, indicating the start of the recovery of the soil system. Post-fire management and temporal recovery of the soil system should consider the obvious difference in soil disturbance under HS and MS between vegetation species.

Soil and water loss due to traditional intensive types of agricultural management is widespread and unsustainable in Croatian croplands. In order to mitigate the accelerated land degradation, we studied different cropland soil management strategies to obtain feasible and sustainable agro-technical practices. A rainfall simulation experiment was conducted at 58 mm h^–1 over 30 min on 10 paired plots (0.785 m²), bare and straw covered (2 t ha⁻¹). The experiment was carried out in maize cultivation (Blagorodovac, Croatia) established on Stagnosols on slopes. Measurements were conducted during April (bare soil, after seeding), May (five-leaves stage), and June (intensive vegetative growth) making 60 rainfall simulations in total. Straw reduced soil and water losses significantly. The highest water, sediment loss, and sediment concentrations were identified in tillage plots during May. Straw addition resulted in delayed ponding (for 7%, 63%, and 50% during April, May and June, respectively) and runoff generation (for 37%, 32%, and 18% during April, May and June, respectively). Compared with the straw-mulched plot, tillage and bare soil increased water loss by 349%. Maize development reduced the difference between bare and straw-mulched plots. During May and June, bare plots increase water loss by 92% and 95%, respectively. The straw mulch reduced raindrop kinetic energy and sediment detachment from 9, 6, and 5 magnitude orders in April, May, and June, respectively. Overall, the straw mulch was revealed to be a highly efficient nature-based solution for soil conservation and maize cultivation protection.

The research objective was to use proximal spectroscopy in visible and near infrared (VNIR) spectra to determine the total leaf nitrogen (TN) content and the above-ground biomass of Miscanthus × giganteus (MxG) grown in the open-roof greenhouse experiment on soil contaminated with cadmium and mercury (100 mg Cd/kg soil; 20 mg Hg/kg soil), in dependence of different soil amendments in four treatments (I-soil without amendment; II-sludge; III-mycorrhizae; IV-MxG ash). Leaf reflectance was acquired using a field spectroradiometer (350–1050 nm) at the end of the vegetation period between 2018 and 2019 (n = 24). TN content was determined using the dry combustion method, while biomass was weighted immediately after the harvest. In terms of the treatment effect, sludge showed the greatest contribution in TN content. Regarding the biomass quantity, MxG ash revealed the best results as soil amendment. Applying the partial least squares regression, complete correlation and low root mean squared error (RMSE) were obtained between predicted and measured values for the validation dataset of TN content (R² = 0.87, RMSE = 0.139%), while a strong correlation was calculated for biomass (R² = 0.53, RMSE = 0.833 t/ha). As an additional tool with analytical methods, proximal spectroscopy is suitable to integrate the optical and physiological properties of MxG, and to assess nutrient stress in crop grown on contaminated soils.

This paper aims to evaluate the ability of VNIR proximal soil spectroscopy to determine post-fire soil chemical properties and discriminate fire severity based on soil spectra. A total of 120 topsoil samples (0–3 cm) were taken from 6 ha of unburned (control (CON)) and burned areas (moderate fire severity (MS) and high fire severity (HS)) in Mediterranean Croatia within one year after the wildfire. Partial least squares regression (PLSR) and an artificial neural network (ANN) were used to build calibration models of soil pH, electrical conductivity (EC), CaCO₃, plant-available phosphorus (P₂O₅) and potassium (K₂O), soil organic carbon (SOC), exchangeable calcium (^exCa), magnesium (^exMg), potassium (^exK), sodium (^exNa), and cation exchange capacity (CEC), based on soil reflectance data. In terms of fire severity, CON samples exhibited higher average reflectance than MS and HS samples due to their lower SOC content. The PCA results pointed to the significance of the NIR part of the spectrum for extracting the variance in reflectance data and differentiation between the CON and burned area (MS and HS). DA generated 74.2% correctly classified soil spectral samples according to the fire severity. Both PLSR and ANN calibration techniques showed sensitivity to extract information from soil features based on hyperspectral reflectance, most successfully for the prediction of SOC, P₂O₅, ^exCa, ^exK, and CEC. This study confirms the usefulness of soil spectroscopy for fast screening and a better understanding of soil chemical properties in post-fire periods.

A future radioactive waste management centre is under development in central Croatia. One of the activities in the centre’s development was to monitor environmental radioactivity before the disposal of radioactive materials. Part of the monitoring programme focused on soil characterisation in the municipality (total area 1308 km²) surrounding the centre, where about 40% of the soil is today used in organic farming. The study included a physico-chemical and radionuclide characterisation of the soil as well as ambient dose rate measurements. The aim of this study was to investigate how the physical and chemical composition of soil affects the concentration of radionuclides ²³⁸U, ⁴⁰K, and ¹³⁷Cs in soil, based on the measured radionuclide concentrations and values of selected soil parameters. Additionally, the ambient equivalent dose rate H*(10)/t was measured and the annual effective dose was calculated for the average person living in the area of interest. The observed ranges of radionuclide concentrations in the soil samples were: 9–72 Bq/kg for ²³⁸U, 65–823 Bq/kg for ⁴⁰K, and 4–80 Bq/kg for ¹³⁷Cs. Ambient dose equivalent rate measurements were in the range of 52–130 nSv/h. The highest measured values were in correlation with higher ²³⁸U activity concentrations in these parts of the investigated area. The results of this study showed that ²³⁸U had a significant correlation with pH; plant available P; sand, silt, and clay content; hydrolytic acidity; CaCO₃; total carbon, organic matter, and total inorganic and organic carbon; and concentrations of Al, Si, Fe, Ca, Ti, K, Rb, Zr, Nb, Y, Sr, Th, and W. ⁴⁰K showed a significant correlation with pH, sand content, hydrolytic acidity, total hydrogen, total nitrogen, CaCO₃, total carbon, total inorganic carbon, and concentrations of Al, Si, Fe, Ca, Ti, Rb, Zr, Nb, P, Y, Zn, and Th. ¹³⁷Cs showed a significant correlation with silt content, total nitrogen, and Si concentration.

In this study, the effect of ammunition on soil quality (physical and chemical indicators) at shooting ranges was investigated at four sites in Croatia. The sites differ in soil type (fluvisols, leptosols and terra rossa) and climatic conditions (Mediterranean and continental). The intensity of shooting range use (calculated from the age of the lane and the average number of targets used per year) and the distance from the shooting range (−40 m to +240 m) were examined in relation to soil chemical composition and soil quality. High contents of Pb and Sb at 100 m from the shooting position were observed in fluvisol and terra rossa soils, and the contamination factors (CFs) ranged from 6 up to 97. The study found high natural soil Cr and Ni content in leptosols and terra rossa due to paedogenic reasons (CFs < 1.3) and soil acidification (a decrease in soil pH_KCl) due to ammunition/target use. Long-term measures for sustainable soil management and environment protection must be taken at shooting ranges to minimise the potential risks to ecosystems, wildlife and human health (an EU strategy).