OBJECTIVES: As a liquid organic fertilizer used in agriculture, digestate is rich in many nutrients (i.e. nitrogen, phosphorus, sulfur, calcium, potassium); their utilization may be however less efficient in soils poor in organic carbon (due to low carbon:nitrogen ratio). In order to solve the disadvantages, digestate enrichment with carbon-rich amendments biochar or humic acids (Humac) was tested. METHODS: Soil variants amended with enriched digestate: digestate + biochar, digestate + Humac, and digestate + combined biochar and humic acids-were compared to control with untreated digestate in their effect on total soil carbon and nitrogen, microbial biomass carbon, soil respiration and soil enzymatic activities in a pot experiment. Yield of the test crop lettuce was also determined for all variants. RESULTS: Soil respiration was the most significantly increased property, positively affected by digestate + Humac. Both digestate + biochar and digestate + Humac significantly increased microbial biomass carbon. Significant negative effect of digestate + biochar (compared to the control digestate) on particular enzyme activities was alleviated by the addition of humic acids. No significant differences among the tested variants were found in the above-ground and root plant biomass. CONCLUSIONS: The tested organic supplements improved the digestate effect on some determined soil properties. We deduced from the results (carbon:nitrogen ratio, microbial biomass and activity) that the assimilation of nutrients by plants increased; however, the most desired positive effect on the yield of crop biomass was not demonstrated. We assume that the digestate enrichment with organic amendments may be more beneficial in a long time-scaled trial.

• MeSH
• Biomass * MeSH
• Charcoal * chemistry   pharmacology   MeSH
• Nitrogen * metabolism   MeSH
• Humic Substances * analysis   MeSH
• Fertilizers MeSH
• Soil * chemistry   MeSH
• Soil Microbiology * MeSH
• Carbon * metabolism   chemistry   MeSH
• Publication type
• Journal Article MeSH
• Retracted Publication MeSH
• Names of Substances
• biochar MeSH Browser
• Charcoal * MeSH
• Nitrogen * MeSH
• Humic Substances * MeSH
• Fertilizers MeSH
• Soil * MeSH
• Carbon * MeSH

Contamination of soil by copper (Cu) has become a serious problem throughout the world, causing the reduction of agricultural yield and harmful effects on human health by entering the food chain. A glasshouse pot experiment was designed to evaluate the potential use of halloysite as an immobilizing agent in the aided phytostabilization of Cu-contaminated soil, using Festuca rubra L. The content of Cu in plants, i.e., total and extracted by 0.01 M CaCl₂, was determined using the method of spectrophotometry. Cu content in the tested parts of F. rubra differed significantly when halloysite was applied to the soil, as well as with increasing concentrations of Cu. The addition of halloysite significantly increased plant biomass. Cu accumulated in the roots, thereby reducing its toxicity to the aerial parts of the plant. The obtained values of bioconcentration and translocation factors observed for halloysite treatment indicate the effectiveness of using F. rubra in phytostabilization techniques.

• Keywords
• aided phytostabilization, clay minerals, metal contaminated soil, red fescue, risk minimization,
• MeSH
• Biodegradation, Environmental MeSH
• Biomass MeSH
• Festuca growth & development   metabolism   MeSH
• Plant Roots growth & development   metabolism   MeSH
• Soil Pollutants chemistry   metabolism   MeSH
• Copper chemistry   metabolism   MeSH
• Aluminum Silicates chemistry   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Soil Pollutants MeSH
• Copper MeSH
• Aluminum Silicates MeSH