Recycling eutrophic lake sediments into grass production: A four-year field experiment on agronomical and environmental implications

• Published in: The Science of the total environment Vol. 870; p. 161881
• Main Authors: Kiani, Mina, Zrim, Jure, Simojoki, Asko, Tammeorg, Olga, Penttinen, Petri, Markkanen, Tuuli, Tammeorg, Priit
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.04.2023
• Subjects: aggregate stability; Agriculture; application rate; Bacteria; Biochar; Carbon Dioxide; case studies; China; Chloroflexi; environment; Eutrophication; field experimentation; fungal communities; Geologic Sediments - chemistry; grasses; Greenhouse gas emission; Greenhouse Gases; growth performance; lakes; Lakes - chemistry; Microbial community; Nutrient leaching; Nutrient recycling; organic matter; phosphorus; Phosphorus - analysis; plant growth; Poaceae; Proteobacteria; risk; Sediment removal; sediments; Soil; soil biota; solubilization; Sustainable ecosystem; China; Greenhouse gas emission; Sustainable ecosystem; Sediment removal; Nutrient leaching; Biochar; Microbial community; Nutrient recycling
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.161881

Inefficient use of phosphorus (P) fertilizers leads to the transfer of P into water bodies, causing their eutrophication. Sediment removal is a promising lake restoration strategy that removes nutrients including P accumulated in lake sediments, and opens the opportunity to use removed nutrients in agriculture. In the present study, we investigated the effects of using a thick layer of sediment from the eutrophic Lake Mustijärv on plant growth, and estimated the environmental impacts of different sediment application methods by analyzing greenhouse gas emissions, N and P leaching, aggregate stability, and soil biota. The field experiment (2017–2020) was established on the lake shore with the following treatments: the agricultural control soil (Soil) surrounding the lake, pure sediment (Sed), biochar-treated sediment (SB), and biochar and soil mixed with sediment (SSB). The sediment-based treatments resulted in a similar grass growth performance to the Soil. The availability of most macro- and micronutrients including P (75 vs. 21 g m−3) were far greater in the Sed compared to the Soil. The sediment-based growing media emitted more CO2 than the Soil (579 vs. 400 mg CO2 − C m−2 h−1) presumably due to the high rate of organic matter decomposition. The bacterial and fungal community structures of the Sed were strongly differentiated from those of Soil. Also, Sed had lower bacterial diversity and a higher abundance of the bacterial phyla associated with solubilizing P including Proteobacteria and Chloroflexi. Sediment-based growing media increased more than seven times the risk of mineral N and P leaching, and the biochar treatment only had a short-lived beneficial effect on reduction of the sediment's leached P concentration. The sediment application rate should be adjusted to match the crop requirements to minimize greenhouse gas emissions and nutrient leaching when upscaling the case study to larger lakes with similar sediment properties. [Display omitted] •Plant growth in excavated lake sediment was comparable to that in agricultural soil.•The Sed had higher CO2 and N2O emissions than the Soil in the first year.•N and P uptakes were higher in biochar-treated sediment than in the Soil.•More N and P leached from the lake sediment than from the Soil.•Sediment and soil have contrasting bacterial and fungal community structures.