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The aim of the research was to investigate interactions between pendimethalin (PE), an active substance of plant protection products, and the humin fraction (HM), which is the most recalcitrant component of soil organic matter. The soil material used for the study was collected from the mollic horizon of two Chernozems different in physicochemical properties. HM was obtained in the solid state after discarding humic acid (HA) and fulvic acid (FA) and digesting the mineral fraction in an HF-HCl mixture. Pure PE and two commercial products containing the substance (Penfox 330 EC and Stomp Aqua 455 SC), dissolved in hexane and added to the HM, were used in the research. The batch sorption experiment was carried out in accordance with OECD Guidelines for the Testing of Chemicals No.106. Spectroscopic methods (UV-Vis-nearIR and fluorescence) were used to assess the molecular characteristics of HM exposed to pesticides. The study showed significant differences in the molecular structures of the tested HM as a result of interactions with the pesticides used. The results revealed that PE had a different effect than the commercial products, and proved that the composition of commercial products significantly modified the strength and ability of organic matter to bind pesticides. This is probably related to the presence of adjuvants that are more competitive in forming bonds with the active sorption sites of HM, and thus strengthen or weaken the process of forming pesticide-HM complexes. As a result, the diversity of the molecular structure of HM and the presence of accompanying substances in commercial pesticide products interact, leading to different sorption mechanisms and durability of the resulting products. [ABSTRACT FROM AUTHOR]

The goal of this study was to evaluate the impact of alkaline fly ash on selected microbiological properties of soils in the vicinity of an electric power plant. The specific objectives were as follows: first, to determine the metabolic activity and functional diversity of soils, such as biological indicators of acidic soil; second, to compare the changes in microbial diversity indicators based on the distance from dumping site of fly ash located in the vicinity of electric power plant; third, to determine the metabolic profile pattern in soils with different pH levels. The study revealed the stimulation of dehydrogenases activity (DHA) and microbial respiration (RESP) by fly ash. It contributed to the increase in metabolic profile expressed as community-level physiological profile differences. The enrichment of fly ash affected the soil microbial characteristics. The values of DHA and RESP decreased with increasing distance from the emission source, whereas the number of utilized substrates (R) increased. However, the utilization of carbohydrates and carboxylic and ketone acids was enhanced with decreasing distance from the emission source, while the utilization of polymers and amino acids was reduced. Furthermore, the forests ectohumus horizons near the emission source were characterized by significantly increased pH level, due to the alkalinity of fly ash particles. [ABSTRACT FROM AUTHOR]

Phosphorus (P) sorption processes in soils contribute to important problems in agriculture: a deficiency of this plant nutrient and eutrophication in aquatic systems. Soil organic matter (SOM) plays a major role in sorption processes, but its influence on P sorption remains unclear and needs to be elucidated to improve the ability to effectively manage soil P. The aim of this research was to investigate the influence of SOM on P sorption. The study was conducted in sandy soil profiles and in topsoils before and after removal of SOM with H2O2. The results were interpreted with the Langmuir and Freundlich isotherms. Our results indicated that SOM affected P sorption in sandy soils, but that P sorption also depended on specific soil properties (e.g. values of the degree of P saturation (DPS), P sorption capacity (PSC) and pH) often related to land use. Removal of SOM decreased PSC in most of the topsoils tested; other soil properties became important in controlling P sorption. An increase in P desorption observed after SOM removal indicated that SOM was potentially that soil constituent which increased P binding and limited P leaching from these sandy soils. [ABSTRACT FROM AUTHOR]

We investigated properties of soil materials derived from reclamation and revegetation on fly ash used to fill-in an area excavated during earlier mining. Changes in the soil environment that take place after this practice have to be well recognized, since knowledge of all aspects of fly ash revegetation is essential to sustainable reclamation. Fly ash was a by-product of lignite-burning in an electric power plant, and it was mixed with biosolids (3000 tonnes of sewage sludge per ha) or boulder clay (4000 tonnes per ha). Eight non-native tree and shrub species were planted in a random pattern on several areas reclaimed in different ways. Raw fly ash and fly ash mixed with biosolids or clay were amended with a mineral fertilizer (yearly doses of 300 kg ha − 1 N, 100 kg ha − 1 P 2 O 5 , 100 kg ha − 1 K 2 O) in years 2000–2003 and in 2006. Eleven years after revegetation, main physical and chemical properties of newly formed soil substrate were determined. Raw fly ash, due to its alkaline character, high salinity, and ability to cement, constituted unfavorable environment for plant growth. However, fly ash with the addition of biosolids or boulder clay exhibited granular soil structure in the surface layers, which facilitated plant root penetration and created favorable conditions for plant growth. In contrast, raw fly ash had lamellar structure, typical for materials of sedimentary origin. The soil substrates investigated on the reclaimed and revegetated materials did not reveal any features of genetic soil horizons, and we concluded that 11 years was insufficient to develop regosols or technosol. However, introduced vegetation resulted in an improvement of the structure of the soil substrate. Mixing of the surface fly ash with biosolids and boulder clay clearly improved several substrate properties, including neutralization of the reaction, a decrease of salinity level, and improvement in physical properties; these effects contributed to an increase in efficiently useful water retention and the amount of water available for plants. [ABSTRACT FROM AUTHOR]