Sławomir S. Gonet

Chromatographic characteristics (HPLC, HPSEC) of humic acids of soil fertilised with various organic fertilisers

The aim of this study was to determine the effect of the size of the soil particle containing organic matter, the type of organic fertiliser (cattle manure, vermicompost, straw) and the decomposition time of these fertilisers in soil on the hydrophilic–hydrophobic properties and polydispersity of humic acid molecules. In the model incubation experiment, organic fertilisers (cattle manure, vermicompost and wheat straw) were mixed with soil material (sandy texture). The soil was sampled for testing after one and three years of incubation. Each sample was separated into two fractions according to graining, grain diameter>0.1 mm (sand fraction) and<0.1 mm (silt and clay fraction), and humic acids (HAs) were isolated. For the HAs isolated, hydrophilic–hydrophobic properties were defined using RP-HPLC, and the division was made into low- and high-molecular-mass fractions (HPSEC). It was demonstrated that introducing organic fertilisers into soil resulted in an increase in the proportion of hydrophobic and high-molecular mass fractions and a decrease in the proportion of hydrophilic and low-molecular mass fractions in the HA molecules. Highest values for the ratio HIL/ΣHOB and lowest values for S1/S2 were noted for HAs of soil mixed with straw. HAs isolated from the fine-grained soil fraction demonstrated a higher degree of ‘maturity’ than HAs from the coarse-grained fraction, which was seen as higher values for HIL/ΣHOB and lower values for S1/S2.

Soil transformations in catchment of disappearing Sumówko Lake (Brodnickie Lake District, Poland)

Soil transformations in catchment of disappearing Sumówko Lake (Brodnickie Lake District, Poland) Lake disappearing is a natural process which contemporarily escalates in consequence of human activity. It is estimated that within the area of Northern Poland from the last glaciation period (ca. 17 000 years ago) a half of lakes totally have disappeared. Areas exposed after water basins desiccation have become native rocks for new soils. Reduced water level results in changes of morphology and properties of the soils situated in direct vicinity of former water basins. The aim of this study was to estimate impact of the catchment groundwater level fall on morphology and properties of direct lake catchment soils, exemplified by the lake Sumowko (Northern Poland) as well as description of new soils formed of lake sediments. The analysis covered 11 soil profiles emerging within former lake basin (newly formed soils) and soils from direct vicinity of former lake (modified through ground water level fall). Obtained results prove that newly formed soils (Limnic Histosol Drainic and Haplic Gleysol) in majority are utilized as grasslands. Soils of the former lake surroundings prove relic features of gleying while they are also subject to mucking process because of dehydration.

Differentiation of soils and land use changes in the vicinity of the disappeared Gardeja lake (Northern Poland)

Abstract The aims of the study were to characterize shoreline soil development and evolution and to determine land use changes (19th to 20th centuries) in the direct catchment of the completely vanished Gardeja lake. The study was based on pedological research and analysis of cartographic materials. The main factor determining the current development of shoreline zone soil cover at the former Gardeja lake was human activity (lake dewatering, further drainage and human-induced erosion). Studied soil profiles were developed from mineral, non-lacustrine materials (upper parts of the slopes) and lacustrine sediments covered with colluvium. The analyzed soil catenas are representative for the undulated young glacial landscape of Northern Poland. The biggest changes of the land use were observed for the class of grasslands that is combined with shrubs (increase of cover area).

The Effect of Humic Substances from Oxyhumolite on Plant Development

The results of many investigations have shown that soil organic matter (OM) significantly affects the growth and yield of plants. This effect can be indirect because OM in general influences soil fertility by determining soil physical and chemical properties (air and water conditions, sorption properties and structure) or direct - connected with the uptake of many other processes, for example, protein and nucleic acids synthesis, enzymatic activity, photosynthesis and respiration (Chen and Aviad 1990, Vaughan and Malcolm 1985). Mechanisms of direct interaction between humic substances and plants are not fully explained yet. Many other problems require profound studies. They are, among others, explanation in which phases of plant development humic substances are important and the description of connections between the structure and chemical properties of humic substances and their effectiveness.