Dragan Cakmak

Soil Properties and Trace Elements Contents Following 40 Years of Phosphate Fertilization

Long-term application of P fertilizers may eventually result in excess and/or toxic accumulations of trace elements and microelements in soil. The effect of monoammonium-phosphate (MAP) on basic soil properties (pH, CEC, texture), the total content of C, N, and F, hot acid-extractable Cu, Zn, Ni, Cr, Pb, Cd, Co, As, Hg, and F, and the content of extractable macro- and trace elements (P, K, Ca, Mg, Al, Fe, Zn, Cu, Ni, Pb, Cd, F) were studied on a Stagnosol soil. Phosphate fertilizer had been applied (26, 39, and 52 kg P ha(-1)) over a 40-yr period. Phosphorus fertilization significantly decreased pH and increased clay content of the soil. Increases were detected in available P, exchangeable Al, Ca, cation exchange capacity (CEC), and clay content. The content of hot acid-extractable Pb increased, whereas the content of diethylenetriaminepentaacetic acid-extractable Pb decreased in accordance with applied rates of MAP. The status of some hot acid-extractable trace elements (Cu, Zn, Ni, and Co) did not change after 40 yr of MAP application, whereas Hg and Cd increased. However, despite the statistically significant increases in the amounts of some potentially toxic elements, they did not accumulate to concentrations considered toxic as overall concentrations are far below the maximum allowed concentrations for natural unpolluted soils.

Contamination, risk, and source apportionment of potentially toxic microelements in river sediments and soil after extreme flooding in the Kolubara River catchment in Western Serbia

PurposeClimate change is contributing to an increase in extreme weather events. This results in a higher river flooding risk, causing a series of environmental disturbances, including potential contamination of agricultural soil. In Serbia, the catastrophic floods of 2014 affected six river basins, including the Kolubara River Basin, as one of the larger sub-catchments of the large regional Sava River Basin, which is characterized by large areas under agricultural cultures, various geological substrates, and different types of industrial pollution. The main aim of this study was to establish the sources of potentially toxic elements in soil and flood sediments and the effect of the flood on their concentrations.Materials and methodsField sampling was performed immediately after water had receded from the flooded area in May 2014. In total, 36 soil samples and 28 flood sediment samples were collected. After acid digestion (HNO3), concentrations of the most frequent potentially toxic elements (PTE) in agricultural production (As, Cd, Cr, Cu, Ni, Pb, Zn) and Co which are closely related to the geological characteristics of river catchments, were analyzed. The origin, source, and interrelations of microelements, as well as background values of the PTE of the river catchment, the pollution index (Pi), enrichment factor (Ef), and geological index (Igeo), were determined, using statistical methods such as Pearson correlations, principal component analysis (PCA), and multiple linear regression (MLRA).Results and discussionThe content of the hot acid-extractable forms of the elements, PCA, and MLRA revealed a heavy geological influence on microelement content, especially on Ni, Cr, and Co, while an anthropogenic influence was observed for Cu, Zn, and Cd content. This mixed impact was primarily related to mines and their impact on As and Pb content. The pseudo-total concentrations of all the analyzed elements did not prove to be a danger in the catchment area, except for Cu in some samples, indicating point-source pollution, and Ni, whose pseudo-total content could be a limiting factor in agricultural production. For the Ef, the Ni content in 59% soil and 68% flood sediment samples is classified into influence classes.ConclusionsThe similar pseudo-total contents of the elements studied in soil samples and flood sediment and their origin indicate that the long-term soil formation process is subject to periodic flooding in the Kolubara River Basin without any significant changes taking place. This implies that floods are not an endangering factor in terms of the contamination of soil by potentially toxic elements in the explored area.

Soil Organic Matter Stability as Affected by Land Management in Steppe Ecosystems

Soil organic matter (SOM) is most reactive and powerful factor in the formation of soil and in its fertility. Formation of soil and accumulation of organic matter are a function of interac‐ tions between biological factors and parent rocks under certain hydrothermal conditions and are one of the sections of a continuous chain of the trophic bounds between different life forms, serving as a first and a last section at the same time. The later is because SOM contain the main nitrogen stock, nearly the half of phosphorus, significant part of sulphur and other macroand micronutrients for sustaining life and productivity of plants. Although soil or‐ ganic matter comprise only five percent of total soil structure it has been a major research topic throughout the history of soil science, which is generally regarded to have been ongo‐ ing for approximately a century [1, 2].

ATMOSPHERIC DEPOSITION EFFECTS ON AGRICULTURAL SOIL ACIDIFICATION STATE - KEY STUDY: KRUPANJ MUNICIPALITY

Abstract Acidification, as a form of soil degradation is a process that leads to permanent reduction in the quality of soil as the most important natural resource. The process of soil acidification, which in the first place implies a reduction in soil pH, can be caused by natural processes, but also considerably accelerated by the anthropogenic influence of excessive S and N emissions, uncontrolled deforestation, and intensive agricultural processes. Critical loads, i.e. the upper limit of harmful depositions (primarily of S and N) which will not cause damages to the ecosystem, were determined in Europe under the auspices of the Executive Committee of the CLRTAP in 1980. These values represent the basic indicators of ecosystem stability to the process of acidification. This paper defines the status of acidification for the period up to 2100 in relation to the long term critical and target loading of soil with S and N on the territory of Krupanj municipality by applying the VSD model. The Inverse Distance Weighting (IDW) geostatistic module was used as the interpolation method. Land management, particularly in areas susceptible to acidification, needs to be focused on well-balanced agriculture and use of crops/seedlings to achieve the optimum land use and sustainable productivity for the projected 100-year period.

Spatio-temporal analysis of land use/land cover change and its effects on soil erosion (Case study in the Oplenac wine-producing area, Serbia)

In this paper, various spatial modelling techniques were applied to analyse changes in soil cover and their impact on soil erosion in the Oplenac wine-producing area in Serbia in the past (1985 and 2013) and in the future (with predictions for 2041). The Integrated Valuation of Ecosystem Services and Trade-offs Sediment Delivery Ratio (InVEST SDR) model and the Modules for Land Use Change Evaluation (MOLUSCE) model, integrated with methods of remote sensing, were successfully applied and were shown to be valid tools for predicting the impact of Land Use Land Cover (LULC) changes when estimating soil loss. The results revealed that the greatest impact of land use changes between 1985 and 2013 was on a reduction in areas under vineyards and an extension of meadow and pasturelands as an individual and social response to economic conditions during the research period. The forecast for 2041 reflected the trends observed in the previous period, with the greatest changes witnessing an increase in urban areas and a decrease in areas of arable land. It was also found that the effect of LULC changes on spatio-temporal patterns in the Oplenac wine-producing area did not have a major impact on soil loss, meaning this area, with its good agro-climatic characteristics, is suitable for the intensification of agricultural production.

Impact of a severe flood on large-scale contamination of arable soils by potentially toxic elements (Serbia)

Extreme flooding in May, 2014 affected the sub-catchments of six major rivers in Serbia. The goal of the study was to evaluate the contents of potentially toxic elements (PTEs) As, Cd, Pb, Cr, Ni, Cu, and Zn in flood sediments and arable soils within the affected sub-catchments using regulatory guidelines and background levels. The sub-catchment of West Morava was selected to assess the degree of sediments and soils contamination and environmental risk [using the Pollution index (Pi), Enrichment factor, Geo-accumulation index, and Potential ecological risk index (PERI)] as well as to identify main PTEs sources by Principal component (PCA) and cluster analysis. Contents of Ni, Cr, As, Pb, and Cu above both guidelines and background levels, and of Zn and Cd above background levels were detected in the sediments and soils from all the sub-catchments. Pi indicted that about 95% of the soils and sediments were extremely polluted by Ni and about 65% slightly polluted by Cr, whereas about 90% were not polluted by As, Cd, Pb, Cu, or Zn. Ef indicated minor to moderate enrichment of the soils and sediments by Ni, and Cr. PCA differentiated a geogenic origin of Ni, Cr, As, and Pb, a mixed origin of Cd and Zn, and a predominantly anthropogenic origin of Cu. PERI of the soils and sediments suggested a low overall multi-element ecological risk. The ecological risk of the individual elements (Eri) for soils was Zn < Cr < Pb < Ni < Cu < As < Cd.

Fractionation, Mobility, and Contamination Assessment of Potentially Toxic Metals in Urban Soils in Four Industrial Serbian Cities

The main soil properties, concentrations of selected elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), and the chemical speciation of each element were determined in urban soil samples taken from urban parks in four Serbian cities (Belgrade, Pančevo, Obrenovac, and Smederevo) exposed to different sources of pollution. Pollution indices (PI, PIN) and factors (MF, ICF, GCF) also were evaluated. The study revealed As and Cd concentrations below the detection limit, whereas the content of Cr, Cu, Fe, Mn, Ni, Pb, and Zn at some sites exceeded the limits established by local regulations, as well as the background values, which may represent an environmental threat. Sequential extraction results show that Fe, Cr, Cu, and Ni were predominantly in the residual fraction at most sites; however, Ni from Pančevo and Smederevo also was bound to the reducible fraction. The presence of Pb at all sites and Zn in Smederevo and Belgrade was mainly associated with the reducible and residual fractions. The highest Mn content was found in the reducible fraction, followed by the acid soluble/exchangeable and residual fractions. Based on the obtained indices and factors, the overall soil status at the selected sampling sites was found to range from the warning limit to slightly polluted, whereby Smederevo had the highest risk, and Pančevo and the control site the lowest risk of contamination by toxic metals.

Soil acidification as a limiting factor to agricultural production in the Municipality of Ljubovija.

The process of soil acidification means, above all, a reduction of soil solution pH. It can be the result of slow, years-long natural process or considerably accelerated due to a combination of natural processes and anthropogenic influences. Acidification is a very important factor in the permanent degradation of the fertility of soil, as the most important and hardly renewable natural resource. Studies on soil susceptibility to the process of acidification were carried out in the Municipality of Ljubovija, using three methods. Defining of the degree of soil susceptibility to the process of acidification allows timely activities aimed at the reduction of overall soil acidity. Management of agricultural land, in isolated areas, must be focused on a balanced use of fertilizers and agrotechnical measures, using proper planting /crops to achieve the optimum use of resources and sustainable soil fertility.