The influence of soil load with polycyclic aromatic hydrocarbons (PAHs) on their contents in selected plants was investigated. A set of experiments was realized in three years. The influence of extreme soil load with PAHs (soil contaminated by floods and sludge application) on their content in plants was observed in a pot trial. A laboratory column extract trial investigated PAHs transfer from the soil into soil solution in different conditions. The results showed that the transfer of PAHs into plants is influenced mainly by chemical characteristics of the substances (the number and position of aromatic nuclei); by soil characteristics (content and quality of soil organic matter) and by plant characteristics (plant species and plant bodies). The roots of tested plants were loaded with PAHs thanks to the transfer of less-nuclei compounds (2–3 nuclei) in soil solution into the roots and thanks to the binding of more nuclei compounds (4–6 nuclei) on organic substances in epidermis and primary bark of roots. These results were confirmed by a laboratory column trial.

Agricultural production is influenced by the water content in the soil and the availability of nutrients. Recently, changes in the quantity and seasonal water availability are expected to impact agriculture due to climate change. This study aimed to test an agricultural product with promising properties to improve soil quality and water-holding capacity during agricultural application. Most of the traditional hydrogels are low-biodegradable synthetic materials with under-researched long-term fate in field soil conditions. The novel, biodegradable hydrogel made from acid whey and cellulose derivatives cross-linked with citric acid was used. The soil-improving effects were tested under controlled experimental conditions with the sandy artificial soil consisting of 10% finely ground sphagnum peat, 20% kaolinite clay, and 70% quartz sand. Soil pH, the content of organic carbon (Cox), total nitrogen (N), available forms of the essential macronutrients (P, K, Ca, and Mg), the cation exchange capacity (CEC), the maximum water capacity (MWC) and water holding capacity (WHC) were determined. The results showed a positive effect on water retention and basic soil properties after the different levels of hydrogel had been introduced into the soil. Generally, the addition of whey-based hydrogel increases the available nutrients concentration and water retention in soil.

The proposal of hierarchical limit system of risk elements (RE) and persistent organic pollutants (POPs) for agricultural soils is presented. The system is not proposed for forest soils (limits are still missing in the Czech Republic). Two levels of limit values were proposed. The first one is the prevention limit statistically derived from the background values of RE and POPs in Czech agricultural soils. The second one is indication limit derived from the risk of plant growth inhibition (RE phytotoxicity effects where the results of experimental trials were utilised), the risk of food chain contamination (RE transfer from the soil into the plants where the results of experimental trials testing the transfer of RE from soils into plants were used) and human health risks (RE and POPs inhalation, dermal and oral intake where the model following US EPA methodology was calculated). The limit values system should replace current version of legislative norm – Decree No. 13/1994 Coll. The principles of limit values assessment for individual levels of the limits are described.

The contamination of agricultural soils by heavy metals is one of the most important methods of soil degradation (EU Soil Thematic Strategy)

A set of 29 pond sediments samples was collected. The sediments were separated into three groups, field, village, and forest pond sediments. The sediment samples were taken from pond bottoms and sediment heaps. The sediment characteristics (pH, CEC, Al-exchangeable, Cox, humus substances), the content of potentially toxic elements and persistent organic pollutants were analysed in the sediments and compared between sediment groups. The comparison of sediment contamination with Czech legislation for sediment use in agriculture was conducted. The village sediments were more loaded by potentially toxic elements and persistent organic pollutants than the others. The pH value of sediments was considered as the properties regulating the retention of potentially toxic elements and their mobility (Al, Cd, Zn). Polycyclic aromatic hydrocarbons (PAHs) were the most problematic POPs group in the sediments. The correlation showed poor dependency of POPs (especially PAHs) content on the content and quality of sediment organic matter.