Browse Our Earth and Environmental Sciences Journals

Earth and environmental sciences cover all planetary and Earth science aspects, including solid Earth processes, development of Earth, environmental issues, ecology, marine and freshwater systems, as well as the human interaction with these systems.

Earth and Environmental Sciences

You are looking at 171 - 180 of 1,536 items for

  • Refine by Access: All Content x
Clear All
Agrokémia és Talajtan
Authors:
I. Potyó
,
I. Kása
,
Cs. Farkas
,
Gy. Gelybó
,
Zs. Bakacsi
,
M. Dencső
,
E. Tóth
, and
Á. Horel

The present study investigated the quantity of total suspended solids (TSS) in three small catchments and compared the data to turbidity measurements. The TSS data were based on filtration, drying and weight measurements, while the turbidity measurements were retrieved using a handheld device with a turbidity sensor. Water was collected daily at the catchment outlets from November 1, 2016 to May 31, 2017, representing the winter and spring seasons. The lowest quantity of TSS was detected at the catchment outlet of the Esztergályi Stream; however, there were two lakes close to the monitoring point where soil particles may have settled, possibly explaining the low TSS values. The Csorsza and Tetves streams had similar TSS values during winter, but in the spring samples the TSS values were approximately three times higher in the Csorsza Stream than in the Tetves Stream. The relationship between water discharge and TSS values was also investigated for the Tetves Stream, but no significant correlations were observed between them. The results suggested that the labour-intensive TSS measurements (e.g. filtration, soil weight measurements) could be replaced to a good approximation using the handheld device. The spatial heterogeneity within and between the catchments influences the amount of suspended sediment and hence the measurement accuracy. Therefore, the use of the handheld device should also be complemented with other methods, such as the filtration used in the present study, to attain more precise values.

Restricted access

The Micro-Deval test method is used for testing of aggregate durability. The present paper focuses on two Hungarian andesites obtained from the quarries of Recsk (Mátra Mountains, Hungary) and of Nógrádkövesd (Cserhát Mountains, Hungary). The aim of this study is to find a simple test method based on the original Micro-Deval test method to assess the long-term durability of aggregates. An additional part of the research was to develop suitable mathematical models that can describe the behavior of the andesite aggregates under continuous abrasive impact. The relevant standard (EN 1097-1:2012) recommends 12,000 rotations to determine the Micro-Deval coefficient required for classification of the aggregates. Within the framework of this research, a modified Micro-Deval test was applied: the number of rotations was increased in several steps and the degree of abrasion was measured afterwards. Regression analyses were used to outline mathematical forms which characterize the dependence between the number of rotations and the degree of abrasion. According to the results, the long-term Micro-Deval tests significantly modify the assessed durability and thus provide information on the long-term abrasive impact. The degree of change depends on the studied material: the ratio of the long-term Micro-Deval coefficients of the two studied andesite types is larger than 3. The regression analyses of the measured Micro-Deval coefficients revealed that quadratic curves are suitable to describe these tendencies for both andesite aggregates.

Open access

The aim of the research was to study the effect of N, P and K supplies on the nutritional status of faba bean in a long-term mineral fertilisation experiment and to determine the nutrient concentrations and nutrient ratios associated with satisfactory nutritional status. The long-term fertilisation experiment was set up in 1989 on chernozem meadow soil calcareous in the deeper layers, with all possible combinations of four levels each of N, P and K supplies, giving a total of 64 treatments. The present paper discusses the results obtained in 2001 and 2002, which can be summarised as follows:

Restricted access

Interactions between the elements N, Cu and Mo were studied on alfalfa in 1996-1999 in a field experiment set up on chernozem loam soil with lime deposits. The ploughed layer of the soil contained 3% humus, around 5% CaCO3 and around 20% clay. Soil analysis showed that the area was well supplied with Ca, Mg, K and Mn had satisfactory Cu content, but was only poorly or moderately supplied with P and Zn. The groundwater depth was 13–15 m and the area was prone to drought. The experiment was originally set up in a split-plot design with 4N × 3Cu = 12 treatments in three replications, giving a total of 36 plots. The N rates, applied as calcium ammonium nitrate, were 0, 100, 200 and 300 kg·ha−1 and the Cu rates, in the form of CuSO4, were 0, 50 and 100 kg·ha−1. In the 5th year of the experiment the 15 m long plots were halved and the two half-plots were separated by a 1 m path. The experiment thus became a strip-split-plot design, consisting of 4N×3Cu×2Mo = 24 treatments in three replications, giving a total of 72 plots. The 48 kg·ha−1 Mo was applied in the form of (NH4)6Mo7O24·4H2O. The main results were as follows:

Restricted access

Interactions between the elements N, Cu and Mo were studied on rape in 2000 in a field experiment set up on chernozem loam soil with lime deposits. The ploughed layer of the soil contained 3% humus, around 5% CaCO3 and around 20% clay. Soil analysis showed that the area was well supplied with Ca, Mg, K and Mn, had satisfactory Cu content, but was only poorly or moderately supplied with P and Zn. The groundwater depth was 13–15 m and the area was prone to drought. The experiment was originally set up in a split-plot design with 4N × 3Cu = 12 treatments in three replications, giving a total of 36 plots. The N rates, applied as calcium ammonium nitrate, were 0, 100, 200 and 300 kg ha−1 and the Cu rates, in the form of CuSO4, were 0, 50 and 100 kg ha−1. In the 5th year of the experiment the 15 m long plots were halved and the two half-plots were separated by a 1 m path. The experiment thus became a strip-split-plot design, consisting of 4N×3Cu×2Mo = 24 treatments in three replications, giving a total of 72 plots. The 48 kg ha−1 Mo was applied in the form of (NH4)6Mo7O24·4H2O. The generative phases of flowering and ripening were characterized by drought and depression. The main results were as follows:

Restricted access

Cadmium accumulation in soils causes ecological, biological and human health risks. Previous studies have shown that reductions in the shoot height and fresh biomass of ryegrass (Lolium perenne L.) are a sensitive indicator of the cadmium pollution level in soils.

Four soils with different types and properties were included in the experiment. In the first period of the biotest, 2 g cotton-wool pads moistened with distilled water were planted with 2 g of perennial ryegrass seeds and the seedlings were grown for 6 days. On the 7th day the cotton-wool pads containing the seedlings were placed on soils polluted with four levels of cadmium: 0, 1, 2 and 4 mg Cd kg−1 soil, added to the soil in the form of cadmium acetate. After a first nutrient-deficient period, the seedlings took up nutrients and toxic substances intensively from the soil samples. After a 14-day period of soil–plant contact the fresh biomass, dry biomass and Cd concentration of the shoots were measured, in addition to which the shoot height was measured every 2 days.

Cadmium treatment significantly reduced the shoot height and fresh weight of ryegrass in all the tested soils, and the damaging effect was proportional to the applied dose. A reduction of more than 10% in the shoot height and fresh weight were observed even at a Cd pollution level of 1 mg Cd kg−1 soil. At the highest Cd level the decrease in shoot height was more than 40% and the decrease in fresh weight more than 35% in all the soils.

The increasing level of Cd application significantly increased the Cd concentration of the shoots. More Cd was accumulated in ryegrass shoots on soils with low pH and low organic matter content.

The results indicate that the ryegrass biotest method is suitable for the characterization of Cd contamination in different soils.

Restricted access

The particle size distribution (PSD) values obtained for a soil database representing the main Hungarian soil types using the Hungarian standard (MSZ-08-0205-78) and the international standard (ISO/DIS 11277:1994) were compared with the pipette method. The relationship between these PSDs and other physical soil characteristics (upper limit of plasticity according to Arany, water vapour adsorption according to Sík) was also analysed, and a suggestion was made of how these results could be converted into each other.

Experience showed that the pre-treatments applied as part of the ISO/DIS method may change the ratio of particle size fractions: there was a significant increase in the clay content, while the silt content decreased to a lesser and the sand content to a greater extent, possibly because some of the particles remain in microaggregate form when the MSZ method is used. The results confirmed the greater accuracy of the ISO/DIS method: the clay contents measured with the ISO/DIS method exhibited stronger correlations with the upper limit of plasticity according to Arany and with hygroscopicity values than those measured with the MSZ method.

The estimated ISO/DIS fractions became much closer to the measured ones when the suggested pedotransfer functions were applied. The conversion method proved to be more reliable for the prediction of clay and sand content than for silt content. In its present form the estimation method is not suitable for replacing the ISO/DIS method, but it could be of good service in research and comparative analysis in cases where only the MSZ method can be used or where only old MSZ PSD data exist.

Open access
Agrokémia és Talajtan
Authors:
Eszter Draskovits
,
Barbara Németh-Borsányi
,
Pierre-Adrien Rivier
, and
Anita Szabó

Agricultural utilisation is one of the most promising uses of sewage sludge in Hungary. Sewage sludge can be applied to agricultural fields in two ways: the injection of dewatered sewage sludge and the application of sewage sludge after composting. Vermicomposting is a special type of composting, where the organic residues are broken down by earthworms. The worms facilitate the decomposition process both by mixing the sludge and by physically degrading it. Earthworm species have various morphotypes requiring different habitats. Compost worms have great adaptability to extreme conditions and are capable of exploiting organic matter in a state of decomposition. Eisenia sp., Eudrilus eugeniae and Perionyx excavatus are important species for vermicomposting.

When examining the role and possibilities of vermicomposting, it is important to compare it with traditional composting methods.

The most important aspect of producing vermicompost is to ensure optimum environmental conditions for the earthworms, especially in terms of temperature, humidity and aeration, which requires constant attention.

An important feature of traditional composting is the thermophilic phase, during which the pathogenic organisms in sewage sludge are destroyed. The thermophilic phase is omitted during vermicomposting due to the thermal sensitivity of the earthworms, but the presence and activity of the earthworms results in similar sterility.

Regarding its nutrient content, vermicompost contains larger quantities of total and plant-available macroelements than conventional composts. A further advantage is the presence of the plant hormone agents excreted by earthworms.

From the environmental point of view, the ability of earthworms to accumulate heavy metals and the role of their special gut flora in the decomposition of organic pollutants could contribute to the wider use of vermicomposting to dispose of sewage sludge.

While vermicompost has many advantages, a number of obstacles need to be overcome before it can be routinely used in Hungary. Many landowners regard sewage sludge compost as hazardous waste that could contaminate their soil and crops rather than as a nutrient and soil amendment. Although numerous studies have been published on sewage sludge, the assessment of long-term effects, including the issues currently of most concern in Hungary, is still lacking.

Vermicomposting is therefore a promising, innovative technology for sewage sludge recycling. Sewage sludge and sewage sludge composts with pollutant contents greater than the limits laid down in Government Regulation 50/2001. (IV.3.) can be made suitable for agricultural use by vermicomposting.

Restricted access
Central European Geology
Authors:
János Haas
,
Tamás Budai
,
István Dunkl
,
Éva Farics
,
Sándor Józsa
,
Szilvia Kövér
,
Annette E. Götz
,
Olga Piros
, and
Péter Szeitz

The 1,200-m-deep Budaörs-1 borehole provided important data for our understanding of the stratigraphy and tectonic setting of the southern part of the Buda Hills. Although previous reports contained valid observations and interpretations, a number of open questions remained. The importance of this borehole and the unsolved problems motivated us to revisit the archived core. The new studies confirmed the existing stratigraphic assignment for the upper dolomite unit (Budaörs Dolomite Formation) as the dasycladalean alga flora proved its late Anisian to Ladinian age assignment. An andesite dike was intersected within the Budaörs Dolomite. U–Pb age determination performed on zircon crystals revealed a Carnian age (~233 Ma), and settled the long-lasting dispute on the age of this dike, proving the existence of a Carnian volcanic activity in this area after the deposition of the Budaörs Dolomite. Palynostratigraphic studies provided evidence for a late Carnian to early Norian age of the upper part of the lower unit (Mátyáshegy Formation). This result verified an earlier assumption and reinforced the significance of the tectonic contact between the upper unit (Budaörs Formation) and the lower unit (Mátyáshegy Formation). Based on structural observations and construction of cross sections, two alternative models are presented for the structural style and kinematics of the contact zone between the Budaörs and Mátyáshegy Formations. Model A suggests a Cretaceous age for the juxtaposition, along an E–W striking sinistral transpressional fault. In contrast, model B postulates dextral transpression and an Eocene age for the deformation. The latter one is better supported by the scattered dip data; however, both scenarios are considered in this paper as possible models.

Open access