Carbon stabilisation in soil is the result of interaction between the chemical and physical mechanisms of protection and the dominance of the mechanism depends not only on the long-term constant characteristics of soil but also on the properties, which can be partly influenced by human activities. In this study, the potential of the soil for stabilisation of carbon (Ps) in different soil types depending on soil properties was compared. Experiment included six soils (Eutric Fluvisol, Mollic Fluvisol, Haplic Chernozem, Haplic Luvisol, Eutric Cambisol, and Rendzic Leptosol) of different land uses (forest, meadow, urban, and agro-ecosystem) in Slovakia. Ps was determined with dependence on the ratio of labile and stable fractions of carbon in the soil macro-aggregates. Ps was in an exponential dependence (r = 0.942; P < 0.01) with production potential of the soil, and the fractions of dry-sieved aggregates larger than 3 mm play an important role in the first stages of the carbon stabilisation. The suitable parameter, which reflects the changes in carbon stability in the soil is the ratio of the labile carbon and non-labile carbon in the soil macro-aggregates (L/NL). Lower values of L/NL that indicate a higher stability of carbon were determined at a higher pH, at the higher content of carbonates and exchangeable basic cations, and at a higherportion of humic acids free and bound with mobile sesquioxides R2O3.
In this study, the soil structure of two soil types (Haplic Chernozems and Eutric Fluvisols) in four ecosystems (forest, meadow, urban and agro-ecosystem) with dependence on humus substances were compared. The stability of dry-sieved and waterresistant macro-aggregates and micro-aggregates with a dependence on the proportion of humus substance fractions was determined. Quantity of humus substances influenced mainly water-resistant aggregates. A positive correlation was recorded between size fraction of 2.3 mm and contents of humus substances (P < 0.01; r = +0.710) and fulvic acids (P < 0.05; r = +0.634), and negative correlation between size fraction of 0.5.1 mm and contents of humus substances (P < 0.05; r = -0.613) and fulvic acids (P < 0.01; r = -0.711). Humic acids influenced mainly the formation of dry-sieved aggregates and fulvic acids played an important role in micro-aggregate formation. The quality of humus substances influenced more intensively the formation of dry-sieved aggregates. There were positive correlations between optical parameters of humus substances and humic acids and larger dry-sieved aggregates (3.7 mm) and negative correlations with smaller (0.5.3 mm). The highest proportions of larger size of water-resistant aggregates (1. 20 mm) were in forest ecosystem, but smaller (0.25.1 mm) agreggates were dominated in agro-ecosystem.
The effect of different doses of NPK fertilizer on the changes in quantity and quality of soil organic matter (SOM) in Rendzic Leptosol was evaluated. Soil samples were taken from three treatments of different fertilization: (1) control - without fertilization, (2) NPK 1 - doses of NPK fertilizer in 1st degree intensity for vine, and (3) NPK 3 - doses of NPK fertilizer in 3rd degree intensity for vine in the vineyard. Soil samples were collected in years 2008-2011 during the spring. The higher dose of NPK fertilizer (3rd degree intensity of vineyards fertilization) was responsible for the higher content of labile carbon (by 21% in 0-0.3 m and by 11% as average of the two depths 0-0.3 m and 0.3-0.6 m). However, by application of a higher dose of NPK (1.39%) in comparison to no fertilizer treatment (1.35%) or NPK 1 (1.35%) the tendency of total organic carbon content increase and hot-water soluble carbon decrease were determined. Fertilization had a negative effect on SOM stability. Intensity of fertilization affected the changes in quantity and quality of SOM; therefore it is very important to pay attention to the quantity and quality of organic matter in productive vineyards.
In this study, differences in soil structure in different ecosystems (forest, meadow, urban, and agro-ecosystem) and soil types (Haplic Chernozem, Haplic Luvisol, Haplic Stagnosol) with a dependence on the influence of quantity and quality of soil organic matter and the particle size distribution on fraction composition of soil aggregates were compared. Soils had different productive capacity and particle size distribution. The most favourable soil structure was in the agro-ecosystem, then in forest, meadow, and urban ecosystem. The worst soil structure was in Haplic Stagnosol. An important indicator in assessing of ecosystem influence, water-resistant macro-aggregates of the 0.5-1 mm size fraction seems to be. This fraction was the only one which was statistically significantly influenced by the ecosystem, and also the only one which was not statistically significantly influenced by the soil type. This fraction also was not influenced either with the quantity and quality of soil organic matter, or with the particle size distribution. The quantity of soil organic matter is reflected in relation to the fractional composition of dry-sieved aggregates and its quality in relation to waterresistant aggregates. Large fractions of water-resistant macro-aggregates were in positive correlation with C : N ratio, the amount of extracted humus substances, or stability and quality of humic acids; while smaller fractions were in negative correlation just with these parameters. Clay and silt fractions had a positive influence on waterresistant macro-aggregates formation, while sand fraction had negative and vice versa.
The countries of the European Union have joined, inter alia, soil protection in the Common Agricultural Policy (hereinafter referred to as CAP). Accelerated soil erosion is a problem resulting from inappropriate land management, which affects both the presence of organic matter and the soil structure. The tool for elimination of negative impacts on soil can be its sustainable use. This requires the use of an accurate system to improve its condition. The first step should be problem identification and localisation. The research is aimed at the identification of water erosion risk areas by using selected methodological procedures. The research area was located at the intensively used hilly land of the Southwestern Slovakia. The digitisation of the manual interpretation of erosion risk areas with the use of aerial photos, erosion modelling, chemical analysis of soil organic matter (SOM) and analysis of soil structure were used. Verification was implemented via the field research with the use of the soil probes. Methods affirmed significant presence of the water erosion in the area. Efficient identification of erosional processes is possible via combination of presented methods by taking into consideration geological, geomorphological, pedological and geographical conditions and the use of the area over a longer period of time. The results of using methods that ensure accurate and effective localisation of erosion surfaces can be used for sustainable land use and its conservation.
Soil organic carbon (SOC) in agricultural land forms part of the global terrestrial carbon cycle and it affects atmospheric carbon dioxide balance. SOC is sensitive to local agricultural management practices that sum up into regional SOC storage dynamics. Understanding regional carbon emission and sequestration trends is, therefore, important in formulating and implementing climate change adaptation and mitigation policies. In this study, the estimation of SOC stock and regional storage dynamics in the Ondavská Vrchovina region (North-Eastern Slovakia) cropland and grassland topsoil between 1970 and 2013 was performed with the RothC model and gridded spatial data on weather, initial SOC stock and historical land cover and land use changes. Initial SOC stock in the 0.3-m topsoil layer was estimated at 38.4 t ha−1 in 1970. The 2013 simulated value was 49.2 t ha−1, and the 1993–2013 simulated SOC stock values were within the measured data range. The total SOC storage in the study area, cropland and grassland areas, was 4.21 Mt in 1970 and 5.16 Mt in 2013, and this 0.95 Mt net SOC gain was attributed to inter-conversions of cropland and grassland areas between 1970 and 2013, which caused different organic carbon inputs to the soil during the simulation period with a strong effect on SOC stock temporal dynamics.