Earth and Environmental Sciences

The current Hungarian Soil Classification System (HSCS) was elaborated during the 1960s, based on the genetic principles of Dokuchaev. It was developed before sufficient data and modern data processing tools were available and served different purposes than current users need or apply it for.The central unit is the soil type, grouping soils that were believed to have developed under similar soil-forming factors and processes. The major soil type is the highest category that groups soils based on climatic, geographical and genetic bases. Subtypes and varieties are distinguished according to the assumed dominance of soil-forming processes and observable/measurable morphogenetic properties. STEFANOVITS (1963) defined the 23 soil-forming processes that have a dominant impact on the differentiation of the 39 soil types of the system.Based on accumulated data and experience, as well as on numerical tools for defining taxonomic relationships a modernization process was carried out. The process included: linking processes to diagnostics, review and numerical study of similarities and dissimilarities of existing units, development of new central units, development of a computer assisted key, and definition of methodology to derive the lower level units. The new, 15 soil types are defined by stronger morphogenetic and measurable criteria, but with the application of legacy data and the developed key, the earlier units can be converted to the new ones, hence the value of legacy data can be preserved.

Bedrock has an essential role in the formation of soils, it fundamentally determines mineral composition. The present research focuses on the minerals in forest soils formed in the Bükk Mountains (NE Hungary). The composition of soil minerals was in accordance with the geological features as well as with the changes in climate and vegetation, which provide a basis for tracking the past of the soil formation mechanisms (Nemecz, 2006). Thus, by studying the mineral composition the formation processes and development of the soils can be unveiled.According to the findings it can be assumed that the investigated soils, although formed primarily on solid limestone, cannot be the products of the weathering of limestone solely, as they also contain significant amounts of silicates. The major part of the soil forming materials presumably originates from earlier dust fallings or from alluvial deposits by erosion. The former assumption is confirmed by the fact that the investigated area is located at a high altitude, thus significant amounts of eroded material could only originate from a short distance, where the bedrock also consists of limestone. Further research is needed for more detailed knowledge on the mineral composition of the soils, thus on the development of the soils and the bedrock of the investigated area.

The obtained results of the present study showed the good applicability of the van Genuchten equation for parameterizing NAPL retention data of soils (R² = 0.99).Sufficient applicability of continuous PTFs for estimating the parameters of NAPL retention curves was found (R² for α, n and θ _s was 0.47, 0.84 and 0.86, respectively).The accuracy of parametric and point PTFs increased in case derived values of the independent variables in addition to the PSD (particle size distribution) fractions, bulk density, CaCO₃ and organic matter content (R² = 0.57–0.90 and RMSE = 2.43–5.67 vol%) were used, as compared to PTFs using only the original values of basic soil parameters as predictor variables (R² = 0,48–0.86; RMSE = 3.56–6.83 vol%).According to the gained results, PTFs seem to be similarly accurate if the particle size distribution of soils — determined by different standard methods — are applied as independent variables.

Three centrally edited nationwide soil maps were published in Hungary between 1953 and 1988. Each of these soil maps has advantages, but serious drawbacks as well. Authors’ hypothesis was that the drawbacks of the individual soil maps are correctable with the help of other soil maps and with ancillary data. Therefore, the oldest soil map was digitized and a study was conducted for the harmonization of data on a 266 km² area at Keszthely (near Lake Balaton) by using the CHAID classification tree method. CORINE land cover database, digital map of surface geology, digital elevation model and derived slope categories were used as ancillary data.The seven source maps contained 7–38 categories. After the intersection of all seven maps, the resulting file contained more than 50,000 polygons and nearly 14,000 category combinations. A variable — showing the probability of the category combinations in relation to the expected areas — was calculated. This was the target variable for classification by the CHAID method, using categories of the seven original maps as independent variables.0.5% of the total area was grouped into 13 less probable classes, which represent the inaccuracies of the initial maps. 99.5% of the total area was classified into 19 classes and some of them were further subdivided on the basis of the geological map. These classes were interpreted as eight WRB soil categories. The final soil map had much better spatial resolution than any of the initial soil maps, non-soil categories were interpreted as soil categories and spatial accuracy was successfully corrected with the proposed method.

Related to ongoing (re)forestation in the Great Hungarian Plain the short-term influence of changing land cover was studied on the grains of skeletal sandy soils. In three sampling areas with forest and grassy/arable control plots, the 0.1–0.2 mm grain size fraction of samples taken every 20 cm from the 0–100 cm sandy soil layer (totalling 22,509 grains) were separated and described with optical mineralogical microscope. In order to distinguish sand grains of forest-covered and control areas (grassland/arable land), the results of mineralogical and morphological observations were compared. It was revealed that the amount of feldspar grains is 8–9 times less than the amount of the quartz ones. The increase in the quartz/feldspar (q/fp) ratio is tied to the “consumption” of feldspars: the intense consumption of potassium by trees. Under the forest-covered fields, the number of in-situ crushed grains increased. Grains with etch pits are frequent in samples from the grasslands (except in Hajdúsámson). In samples of forest-covered areas a greatly increased number of brown grains with limonite and/or humus films were observed. The gained results can be useful in proving earlier land use in forested fields.

Potassium uptake is the result of numerous simultaneous processes influencing the potassium dynamics in the rhizosphere.The presented research has focused on plant-soil interactions in the potassium supply of soil in the root environment of maize. It was assumed that: 1. roots promote the mobilization of K by the acidification of the rhizosphere soil, 2. roots increase wetting-drying cycles in their environment, and 3. soil total K content affects K release and fixation in the bulk of soil and the root environment.The promoting effect of root activity was detected on K release from soil when feldspar was added as K source to the root environment. A 2-unit reduction of soil pH multiplied K concentration in the soil solution, depending on the feldspar rate. Feldspar application significantly increased the solubility and release of potassium into the soil solution.The effect of pH reduction on the K concentration of soil solution was several magnitudes higher than that of the wetting-drying cycles both in the untreated and feldspar treated soils.Potassium uptake by maize over two generations greatly exceeded the exchangeable pool in the growing media. As a consequence of the exhaustive K uptake K release slowed down to the soil solution, as reflected in the H₂O extractable K and ExK contents.Significant K fixation was detected after the K removal of maize in feldspar treated soils. On the contrary, in the treatments without plants increasing feldspar rates increased both H₂O extractable K and ExK contents.One-term Langmuir equation, corrected with the originally sorbed amount of K, was fitted to measured data. The maximum amount of potassium adsorption (K_max, mg∙kg⁻¹) and the equilibrium constant (k) were calculated. The potassium buffering capacity was estimated at zero equilibrium concentration. Both K buffering capacity and the energy of K fixation were high for the rhizosphere soil. In rhizosphere soil samples the energy of K fixation was one magnitude higher as compared to the bulk soil and decreased substantially with feldspar addition. In soils without plants the k equilibrium constant did not change as the result of drying-wetting process only in the case of the 50% soil/feldspar mixture.In the liquid phase of the soil without feldspar application potassium concentration decreased in the one-year drying-wetting cycle, presumably it got into more strongly bounded forms in the low K status soil. In 50% feldspar enriched soil samples potassium concentration in the soil solution increased, likely as a consequence of a slow dissolution of the K content of feldspar.

Roadside dusts were studied to explain the spatial variation, and present level of contaminant elements (including Pt, Pd and Ir) in Budapest and Seoul, the capitals of Hungary and Seoul. Road dust samples were obtained twice from traffic focal points in Budapest centre (four bridges, Margaret Island, two main railway stations, main roads) and the agglomeration (suburbs) of Budapest. Similarly, samples were collected from six sites having high traffic volumes in Seoul metropolitan city and from two control sites within the suburbs of Seoul, for comparison. The samples were analysed for contaminant elements by ICP-AES and for Pt, Pd and Ir by ICP-MS.The level of contaminant elements in road dusts were in the range of 67.6 g∙kg⁻¹ and 0.6 μg∙kg⁻¹ for Budapest; 50.2 g∙kg⁻¹ and 0.5 μg∙kg⁻¹ for Budapest suburbs; 43.5 g∙kg⁻¹ and 3.3 μg∙kg⁻¹ for Seoul samples. The Geo-Accumulation Indexes (GAI) of contaminant elements for Budapest, Budapest suburbs and Seoul ranged between 3.88 and −0.03; 2.74 and −0.13; 4.23 and 1.22; Pollution Indexes (PI) of the contaminant elements were in the range of 4.2 and 0.6; 0.9 and 0.4; 7.8 and 2.7; Contamination Indexes (CI) of the contaminant elements ranged from 27.1 to 3.3; 4.9 to 2.7; 21.8 to 10.2, respectively.Pt, Pd and Ir concentration levels (μg∙kg⁻¹) were in the range of 133 and 1.9, 170 and 12.8, 4.5 and 0.4 for Budapest; 37 and 3.6, 39.4 and 11.3, 0.8 and 0.2 for Budapest suburbs; 98.5 and 25.6, 148 and 30.6, 5.6 and 2.1 for Seoul.Correlations between the Pollution Index (PI) and Contamination Index (CI) of the platinum metals in road dust samples were: −0.4090 (Ir), −0.3098 (Pd), −0.1994 (Pt) for Budapest centre; 0.8343 (Ir), −0.7652 (Pt), −0.7626 (Pd) for Budapest bridges; 0.5266 (Ir), −0.2863 (Pd), −0.0333 (Pt) for Budapest suburbs; and 0.3193 (Pd), 0.2874 (Ir), −0.0017 (Pt) for Seoul, respectively. The highest Pt, Pd and Ir levels in road dusts were found in samples originating from the major roads with high traffic volume. Significant differences in Pollution Index (PI) and Contamination Index (CI) between Seoul and Budapest were 4.0 and 5.9 for heavy traffic roads; 2.9 and 11.0 for roads with light traffic. Light traffic roads reflect that an important source of Pt, Pd and Ir in roadside environment is the automobile catalytic converter. Road dusts with high Pt, Pd and Ir levels were enriched with traffic-related contaminant elements as well.

The aim of the present study is a better understanding of the distribution and formation of salt efflorescences by mineralogical examination. Dominant sodium sulphate and sodium chloride surface efflorescences were selected for investigation. 24 samples were collected between 1999 and 2005 from 16 sites. The soil types were solonchak and meadow solonetz.Basic soil and groundwater analyses were performed according to the standard methods. Minerals were determined by X-ray diffractometry and SEM combined with microanalysis. The evaporation experiments were carried out in a Sanyo Versatile 350 HT environmental test chamber.It was concluded that common sulphate salts form rare and unique mineral associations on salt affected soils in Hungary.Comparing the groundwater compositions and the mineral associations of surface efflorescences or that of precipitated evaporites of groundwaters, the conclusion can be drawn that groundwater composition is reflected much better by the mineral association of experimentally precipitated evaporates of the groundwater than by the mineral associations of surface efflorescences. These differences suggest that the soil matrix may have an effect on the crystallization of minerals (e.g. gypsum, thenardite) in the efflorescences. The differences also suggest that in the surface efflorescences the precipitation process does not come to the end in all cases (minerals with high solubility are missing).Concerning the data on groundwater level depths in case of different (sodium carbonate versus sodium sulphate and sodium chloride) efflorescences, there is a tendency of declining groundwater table in the sequence of these soils. This difference can be explained by the difference (increase) in the solubility of various salt minerals.It was recognized that the change in the major component of surface efflorescenes in time (i.e. the sodium carbonate and sodium carbonate chloride versus sodium sulphate efflorescences before and after 1998) can be explained by the decline of the groundwater level and by the decreasing hydromorphic influence in the lowland area during the 19^th and 20^th century.Finally it can be stated that the presented research — which mainly focused on mineralogical aspects — has contributed to the earlier knowledge on surface salt efflorescences, which was based only on their chemical composition.

Kutatásaink során tételesen megvizsgáltuk három tiszántúli mintaterület (Mikepércs, Hajdúsámson és Nyírbogát) erdős- és kontrollfúrásának felső egy méterén húsz cm-enként vett minták 0,1–0,2 mm-es homokfrakcióinak szemcséit, összesen 22.508 db szemcsét. Megállapítottuk a homokszemcsék ásványi összetételét, alakját és a felületükön látható bélyegeket. A vizsgálat célja az erdő- és kontrollterületi fúrásminták különbségeinek kimutatása, és a talajban végbemenő folyamatokkal történő összefüggésbe hozása.Mivel a területek földtani szempontból homogénnek tekinthetők, statisztikai módszerekkel vizsgáltuk, hogy a minták mennyiben hasonlóak fúrás és mintaterület szinten, és melyek azok a paraméterek, amelyek alapján az erdős és a kontrollminták elkülöníthetők.Az ásványi összetétel esetében összehasonlítottuk a kvarc/földpát részarányt (q/fp), a vas-hidroxidok és a gipsz mennyiségét. A szemcsemorfológia alapján a szögletes (éles, koptatásmentes) szemcsék részaránya, a szemcsefelület morfológiája esetében pedig a kioldás (korrózió), a gipszbevonatok és a szemcséket bevonó barna, limonitos/humuszos hártya gyakorisága hordoz információt a talajosodás során történő változásokról.Az erdővel huzamosan fedett területen az intenzívebb mállás miatt a q/fp arány nagyobb, mint a füves kontrollterületeken. A vas-hidroxid akkumuláció lényegesen nagyobb a folyamatosan tölgyerdővel borított területen, míg az akác- és a fiatal nyárerdő esetében csak a gyepterületek gyenge felszín közeli vasakkumulációja volt észlelhető. A tölgyes és a nyaras fás növényzet gyökérzónája alatt a szulfátok kismértékű feldúsulása észlelhető.A szemcsemorfológiailag éles-hegyes szemcsék az „in situ” felaprózódást jelzik, amelyek végig jelen vannak mind a hat fúrásmintában. A mikepércsi kontroll esetében pásztázó elektronmikroszkópos (SEM) vizsgálattal is valószínűsíthető a fagyhatás. A nyírbogáti 2. fúrás anyagában viszont feltételezhető, hogy a nyárerdővel való fedettség esetében a biológiai felaprózódás került előtérbe. A kontrollterületek fúrásaiban jól láthatók az eredeti (folyóvízi szállításra utaló) felületet felülíró korróziós kimarások, üregek, amelyek a hajdúsámsoni akácos 60 cm alatti mintájában is jelen vannak.Vizsgálatunk eredményeit összegezve megállapíthatjuk, hogy a homokos vázanyag részletekre kiterjedő vizsgálata felhívja a figyelmet a talajban végbemenő változásokra, ezen belül az erdős és a füves területek közötti különbségekre. Így az ilyen jellegű vizsgálatok jól kiegészítik a területekre vonatkozó cönológiai, talajtani és vízföldtani kutatásokat.Jelen munkát az OTKA NN79835 számú pályázata („Sekély talajvizű területen telepített ültetvények által a talajban és altalajban okozott sófelhalmozódás statisztikai és hidrológiai modellezése”) támogatta. Köszönet a NYÍRERDŐ Zrt-nek, hogy hozzájárult az általuk kezelt mikepércsi erdőterületen kitűzött fúrások kivitelezéséhez, valamint a jelen munkában szereplő további mintaterületek tulajdonosainak, akik engedélyezték a vizsgálatok elvégzését.

A barlangi üledékek vizsgálatát 2008-ban kezdtük meg. Mivel konkrét információink az esetleges szennyezőkről nem voltak, így az első három év folyamán (2008, 2009 és 2010 években) elsősorban a potenciális szennyező anyagokat vettük számba, így vizsgáltuk az üledékek nehézfémtartalmát, szerves szennyezőit és mikrobiológiai állapotát. Az első három év adatai alapján a következő négy környezeti problémát azonosítottuk:

1. — Nehézfém-szennyezettség szempontjából a barlangi üledékek tisztának mondhatók, kivéve a kadmiumot, melynek értéke gyakran megközelíti, ritkán meg is haladja a talajokban megengedett környezetvédelmi határértéket.
2. — Szerves szennyezők szempontjából szinte minden évben megjelenik a ftalátok csoportja, melyek műanyaglágyítóként használt vegyületek, és ezáltal jól jelzik a barlangba bejutó vizek szeméttel történő találkozását. Itt elsősorban a patakmedrekbe öntött hulladékból visszamaradó műanyag zsákokból és palackokból kioldódó anyagait értjük, valamint a szennyvíz bekeveredésének lehetőségét.
3. — Nem állandó, de sajnos gyakran visszatérő probléma az olajszármazékok megjelenése a barlangi üledékekben, melyeket elsősorban a nedves években lehet kimutatni. Sajnos, az olajszármazékok okozta szennyezések mértéke nagyon komoly szintet érhet és ért is el az elmúlt három évben megmintázott talajokban, kiküszöbölésükhöz részletes szennyező forrás vizsgálatokra volna szükség.
4. — A ftalátok kvantitatív vizsgálata igen komoly környezeti terhelést jelez, mind a barlangi üledékek, mind a felszíni és a felszín alatti vizek esetében. A folyóvízi üledékek - elsősorban a felszíni patakok, de sajnos a barlangi patakok egy részében is - gyakran a határértéket többszörösen meghaladó koncentrációt mutat. A felszíni vízfolyások esetén a határérték több mint 20-szorosát is elérhetik a mért koncentrációértékek.

1. 1. Javasoljuk a barlangok felszíni vízgyűjtő területeit érintő talajmintázás elindítását a nagy kadmiumtartalom megmagyarázása, illetve az esetleges felszíni és a felszín alatti Cd-tartalom összevetésére.
2. 2. Javasoljuk a ftalátok rendszeres mérését, monitorozását a barlangi talajokban, illetve a felszíni vizekben, azok üledékeiben, illetve a vízgyűjtő terület talajain, elsősorban a szennyezés forrásának tisztázása és kiküszöbölése céljából.
3. 3. Javasoljuk továbbá a felszíni olajszennyezési „utak” feltárását, azon olajforrások lokalizálását (pl. utak, létesítmények), melyek tényleges hatást gyakorolnak a barlangok vízminőségére. Ezek a területek, illetve szennyező források aztán a Bükki Nemzeti Parkon belüli szabályozások okszerű és helyspecifikus újragondolását segíthetik elő a karsztvizek védelme érdekében.