Impact of Two Different Biochars on Earthworm Growth and Survival


  • Amanda M. Liesch Kansas State University, Manhattan, KS 66506, USA
  • Sharon L. Weyers USDA - Agricultural Research Service, North Central Soil Conservation Research Laboratory, Morris, Minn.
  • Julia W. Gaskin University of Georgia
  • K. C. Das University of Georgia


pyrolysis, biochar, Eisenia fetida, toxicity, artificial soil test


Interest in the use of biochar as a soil amendment to increase soil fertility and sequester carbon is increasing. However, the effects of biochar on the survival and reproduction of earthworms are unknown. The toxicity of two different biochars (pine chip and poultry litter char) on Eisenia fetida applied to an artificial soil (70% sand, 20% kaolin, and 10% sphagnum) was investigated at five different application rates of 0, 22.5, 45, 67.5, and 90 Mg ha-1. Earthworm mortality and weight loss reached 100% at the two highest application rates of poultry litter biochar, whereas mortality and weight loss with pine chip biochar did not differ from control treatments. Soil pH, which also increased in controls and pine chip biochar treatments over the course of the incubation, was the most likely cause of earthworm mortality in all treatments. However, it was apparent that poultry litter biochar provided a more stressful environment to earthworms since many worms died in the first five days of incubation. This stressful environment was most likely due to the presence of ammonia gas in addition to high pH, which increased from 7.2 to 8.9 with increasing application rates of poultry litter biochar (pH 10.3). Potentially toxic micronutrients, including As, Zn, Cu, Fe, and Al, present at sub-toxic levels in poultry litter biochar treatments on an individual basis were not likely to have contributed to earthworm mortality; additive effects, however, were not established. Poultry litter biochar also had high Na and Mg content, which could have led to high salinity. As biochar characteristics depend on the feedstock and conditions of pyrolysis, toxicity screening of biochars, particularly those likely to increase soil pH, prior to land application is recommended.

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How to Cite

Liesch, A. M., Weyers, S. L., Gaskin, J. W., & Das, K. C. (2010). Impact of Two Different Biochars on Earthworm Growth and Survival. Annals of Environmental Science, 4. Retrieved from