Modelling the flow and transport of fluids (water and non-aqueous phase liquids or NAPLs) in porous systems or soils requires the accurate and reliable determination of basic input modelling parameters, such as liquid retention (Pc–S) and conductivity (Ksat, Kh). Methods for the determination (measurement and estimation) of water retention and conductivity have improved enormously over the last 60 years (Table 1). Promising results verified the applicability of pedotransfer functions (PTF) and their incorporated versions into software and submodels. However, the development of models was only aimed at improving methods with which these hydrological parameters could be determined for water, while calculations for NAPLs can still only be made indirectly. Several studies (e.g. in the petroleum industry, and research for environmental or hydrological purposes) revealed differences in the relationship between the hydraulic properties and pore system of the porous solid phase. Interactions (swelling-shrinking, desaggregation, etc.) between the phases may be significantly different in water/soil and NAPL/soil systems, affecting the efficiency of modelling. However, relatively few well-documented results have been published on the measurement of these hydraulic properties for NAPL-type fluids using a sufficient number of real, especially undisturbed soils. The establishment of databases of this sort might provide a basis for creating and developing PTF-type estimation methods for predicting NAPL retention and conductivity. Furthermore, it might improve our knowledge on interactions specific to the solid and fluid phases of pore systems, and also on the soil properties influencing the pore size distribution of soils (e.g. soil structure, the size distribution, morphology or stability of aggregates) and their relationship with the hydrophysical properties of the soil.
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.
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:
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:
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:
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.
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.
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.