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  • Author: Zsuzsanna Ladányi x
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Abstract

Tree ring width is influenced by several internal and external factors, among which climate became one of the most dominant due to the altering conditions and patterns of precipitation and temperature. The study aims to analyse the interrelationship between tree ring-width and the dominant environmental parameters in a landscape exposed to water scarcity in the past decades due to climate change and human interventions. Scots pine (Pinus sylvestris), black locust (Robinia pseudoacacia) and white poplar (Populus alba) plantations were sampled to reveal their exposure to climatic forcing and water scarcity (different water availability). Correlation and similarity analysis were carried out to compare the calculated ring-width indices to climatic parameters and aridity indices. Tree ring sensitivity was assessed to reveal the impact of water scarcity on yearly ring-growth. Spatial overlapping of significance levels and mean sensitivity with the hydrological changes of the past decades were evaluated to reveal presumable spatial differences of the investigated samples. In the study area (South Danube-Tisza Interfluve) droughts and the deep groundwater table had both impacts on tree growth. The spectacular decrease of ring-width corresponds to the drought years determined by the investigated aridity indices. The relationship between the climate parameters and the ring-widths varies spatially with the changing site conditions. The highest level of correlation coefficients was experienced in areas with the lowest level of water availability. Ring-width sensitivity assessments showed an increasing tendency of sensitivity when comparing the consecutive decades, except for samples with favorable water availability.

Abstract

The riverbed morphology of sand-bedded rivers is dynamically changing as a consequence of quasi continuous bedload transport. In the meantime, the dimension, size and dynamics of developing bedforms is highly depending on the regime of the river and sediment availability, both affected by natural and anthropogenic factors. Consequently, the assessment of morphological changes as well as the monitoring of riverbed balance is challenging in such a variable environment. In relation with a general research on the longer term sediment regime of River Maros, a fairly large alluvial river in the Carpathian Basin, the primary aim of the present investigation was to assess uncertainties related to morphological monitoring, i.e. testing the reproducibility of hydromorphological surveys and digital elevation model generation by performing repeated measurements among low water conditions on selected representative sites. Surveys were conducted with the combination of an ADCP sonar, GPS and total station. The most appropriate way of digital elevation modelling (DEM) was tested and 30-point Kriging was identified to be optimal for comparative analysis. Based on the results, several uncertainties may affect the reproducibility of measurements and the volumetric deviation of DEM pairs generated. The mean horizontal difference of survey tracks was 3-4 m in case of each site, however this could not explain all the DEM deviation. Significant riverbed change between measurements could also be excluded as the main factor. Finally, it was found that results might be affected greatly by systematic errors arising during motor boat ADCP measurements. Nevertheless, the observed, normalised and aggregated DEM uncertainty (600-360 m3/rkm) is significantly lower than the changes experienced between surveys with a month or longer time lag. Consequently, the developed measurement strategy is adequate to monitor long term morphological and sediment balance change on sand bedded large river.

Abstract

Agriculture is one of the major fields, where sewage sludge can be used. Its high nutrient content can contribute to the improvement of important soil properties, such as nutrient content, water balance and soil structure. However, sewage sludge may contain hazardous components, such as pathogens and pollutants. Therefore, it is important to monitor the effects of its field application. In this paper, we assessed the impacts of two low-dose (2.5 m3/ha) municipal sewage sludge compost applications (in 2013 and in 2017) in a 5.6 ha arable land in southeast Hungary (near Újkígyós), located in the Hungarian Great Plain. The nutrient and the heavy metal contents in the upper soil layer (0-30 cm) of the studied Chernozem soils were compared between two sampling campaigns in 2013 (before the compost applications) and in 2018 (after the compost applications). Basic soil properties (pH, salinity, humus content, carbonate content, Arany yarn number) complemented with nutrient content (K2O, P2O5, NO2+ NO3) and heavy metal content (Cd, Co, Cr, Cu, Ni, Pb and Zn) analyses were performed. The results show that no significant change can be noticed in the baseline parameters over the 5-year period. The slight increase in the P2O5, NO2+ NO3 content is closely related to the beneficial effects of the sewage sludge deposition. The soil-bound heavy metal load did not increase significantly as a result of the compost treatments, only nickel showed a slight increase in the topsoil. In all cases the heavy metal concentrations did not reach the contamination thresholds set by Hungarian standards. The results provided positive evidences proving that low dose municipal sewage sludge compost disposal on agricultural land is safe, and can be considered as a sustainable soil amendment for agriculture in compliance with legal requirements.

Abstract

An integrated approach was applied in this article to provide a medium-scale map of land use intensity for Hungary. The main goal was to estimate its value by a small set of parameters, which are freely available and have a high resolution. The basis of the evaluation was the CORINE 2012 dataset, and a matrix method was applied to integrate the ratio of natural/semi-natural vegetation, woody vegetation and the Natural Capacity Index in the assessment to describe the complex approach of land use intensity. The medium level land use intensity map provides information for decision makers/landscape planners on the current status and spatial pattern of anthropogenic impact and indicates those hot-spots where land use intensity is high and should be focused research and management to intervene in order to encourage sustainable land use. 46% of the arable lands in Hungary show the most intensive land use. Comparing the map with the previously published hemeroby map of Hungary, more intensive impact on landscape transformation through human action was found. In agricultural areas both researches agree that the intensity and human activity is really high, and the lowest intensity class is rare in Hungary except for mountain regions and protected areas.

Abstract

Several environmental and economic consequences of drought and the accompanying water shortage were observed in the plain area of the Carpathian Basin in the last decades. This area is mostly used for agriculture, thus it is a key problem in the future to maintain food safety in the changing circumstances. Therefore, involvement and identification of areas affected by drought hazard and revealing steps of efficient adaptation are of high importance. In this study influence of drought severity on agricultural production is investigated in the Hungarian-Serbian cross-border area. The tendency in drought severity was analysed by PaDI and MAI drought indices. The effect of drought on agricultural production is evaluated on maize yield data as the most drought sensitive crop in the region. Increasing drought frequency and severity was indicated for the study area for the period of 1961-2012. The spatial assessment of annual PaDI maps revealed the higher exposure of the north and northeastern part of the study area to drought, where drought frequency was also experienced to be the highest. Increased sensitivity was detected based on maize yield loss after the early 1990s and annual yields were in strong connection with d rought severity. In spite of the technological development of agriculture, environmental factors still substantially affect crop yie lds. The observed unfavourable changes in the region mean that water management and spatial planning faces conceptual challenges to prevent and mitigate the damages of drought.

Abstract

Grain-size distribution has become in the last years an important indicator in the analysis of periglacial processes and landforms. However, as they exhibit a complex sedimentology, careful sampling is required to draw meaningful conclusions. The aim of the present study was therefore to validate the sampling procedure carried out on solifluction forms and to evaluate the effect of sampling pretreatment during grain size analysis. A comparison between multiple measurements of grain size distribution using the laser diffraction method (LDM) was performed on 54 sediment samples collected from different solifluction landforms at different depths in the alpine area of the Southern Carpathians. The results of parallel measurements were compared using textural and statistical indicators. The received distributions reinforced the properness of field sampling procedure in most of the cases. The results of textural classification and fractional composition showed a high consistency between the two parallel measurements made on untreated and pretreated samples. An overall fining as a matter of etching was identified. Relative deviation increased and correlation decreased as pretreatment advanced. HCl etching resulted a greater deviation and variability in case of the sand fraction, H2O2 rather affected the silt fraction. The greatest deviations were experienced in case of landforms developed on crystalline limestone. Pretreatment of samples introduced a major uncertainty to further comparison and interpretation. Thus, multiple LD measurements on a representative group of samples from the entire sample set were suggested before the geomorphological or environmental interpretation of results to decrease the uncertainties and to validate the processes