Optimizing biochar addition for vermicomposting: a comprehensive evaluation of earthworms’ activity, N2O emissions and compost quality
Biochar addition has been widely used in the field to mitigate soil nitrous oxide (N 2 O) emissions, and can be considered as a potential method to reduce N 2 O emissions during vermicomposting. However, excessive biochar addition may inhibit earthworms’ activity. Thus, it is crucial to clarify the...
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Published in | Biochar (Online) Vol. 5; no. 1; pp. 1 - 12 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Singapore
Springer Nature Singapore
17.01.2023
Springer |
Subjects | |
Online Access | Get full text |
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Summary: | Biochar addition has been widely used in the field to mitigate soil nitrous oxide (N
2
O) emissions, and can be considered as a potential method to reduce N
2
O emissions during vermicomposting. However, excessive biochar addition may inhibit earthworms’ activity. Thus, it is crucial to clarify the optimum addition volumes of biochar during vermicomposting. This study evaluated the impact of addition of various amounts of biochar (0, 5, 10, 15, 20 and 25% of total amount of feedstock) on earthworms’ (
Eisenia
fetida
) activity, N
2
O emission and compost quality during vermicomposting. Compared with the treatment without biochar added, 5% of biochar application significantly increased earthworm total biomass (from 177.5 to 202.2 g pot
−1
), and cumulative burrowing activity (from 47.0% to 52.2% pixel per terrarium). The increased earthworms activity stimulated the vermicomposting process and led to the best quality of compost, which showed the highest total nutrient content (5.38%) and a significantly higher germination percentage of seeds (88%). Although N
2
O emissions were slightly increased by 5% biochar addition, a non-significant difference was found between the treatment with 5% biochar and the treatment without biochar added. On the contrary, 20% and 25% biochar addition not only lowered N
2
O emissions, but also significantly decreased the quality of compost. The results suggest that 5% biochar application is an appropriate amount to improve the quality of compost without significant N
2
O emissions.
Graphical Abstract
Highlights
Cattle dung can be effectively managed through vermicomposting
Biochar showed both positive and negative effects on earthworms’ performance
5% biochar addition promoted compost quality by stimulating earthworms’ activity
Higher doses of biochar were not suitable for vermicomposting
Available N and functional genes drove compost quality and N
2
O emissions
Biochar increased AOB but decreased
nirS
gene numbers in fresh cast of earthworms |
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ISSN: | 2524-7867 2524-7867 |
DOI: | 10.1007/s42773-022-00203-9 |