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The database of Polish arable mineral soils is presented. The database includes a lot of information about the basic properties of soils and their dynamic characteristics. It was elaborated for about 1 000 representative profiles of soils in Poland The database concerns: particle size distribution, organic carbon content, acidity-pH, specific surface area, hydrophobicity - solidliquid contact angle, static and dynamic hydrophysical properties, oxidation-reduction properties and selected biological (microbiological) properties of soils. Knowledge about soil characteristics is indispensable for description, interpretation and prediction of the course of physical, chemical and biological processes, and modelling these processes requires representative data. The utility of simulation and prediction models describing phenomena which take place in the soil-plant-atmosphere system greatly depends on the precision of data concerning characteristics of soil. On the basis of this database, maps of chosen soil properties are constructed. The aim of maps is to provide specialists in agriculture, ecology, and environment protection with an opportunity to gain knowledge of soil properties and their spatial and seasonal variability.

The cyanobacterium (blue‐green alga) Oscillatoria perornata is the major cause of musty off‐flavor in farm‐raised channel catfish Ictalurus punctatus in western Mississippi. Currently, the only federally approved compounds for use as selective algicides in catfish aquaculture ponds in the southeastern United States are the herbicide diuron and copper‐based products (e.g., copper sulfate). Due to environmental issues and the broad‐spectrum toxicity of these synthetic algicides to nontarget organisms, there is a need for environmentally safe algicides for controlling O. perornata in catfish ponds. Laboratory bioassay screening of the natural product SeaKleen, a quinone‐based biocide used to treat the ballast water from ships, found that it is selectively toxic towards O. perornata compared with the green alga Selenastrum capricornutum. Subsequently, efficacy testing of SeaKleen was performed using limnocorrals placed in catfish aquaculture ponds containing O. perornata blooms. Two studies were performed: a dose–response study and a single‐effective‐concentration study. For both studies, water samples were removed from inside the limnocorrals before and after the application of SeaKleen. These water samples were monitored for levels of the musty off‐flavor compound 2‐methylisoborneol (MIB), chlorophyll‐a levels, and phytoplankton community structure. Results from both studies found that approximately 1.3 mg/L SeaKleen was effective in significantly reducing the levels of chlorophyll a and MIB compared with controls. In addition, the abundance of O. perornata and other predominant species of filamentous cyanobacteria were significantly reduced compared with controls. Green algae and diatoms were not significantly affected. Additional studies are needed to determine the potential of SeaKleen as a selective algicide in commercial catfish aquaculture.

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The changes of Eh and pH in soil suspension (Ah-horizon of a Mollic Gleysol) and Mn" or Fe2+ concentrations in the equilibrium soil solution at different levels of glucose (0%. 0.5% and 1%) and MnOl (0%.0.025%.0.05%and 0.1%) orFe20, (0%,0.025%,0.0S% and 0.1%) were examined. It was found that the degree of Mn-and Fe-reduction in soil depends mainly on the presence and the amount of an easily decomposable carboo source and to a minor degree on the content of native or added forms of Mn02 or Fe203 in the soil.