Earthworm Field Study
Introduction
Earthworms are recognized as indicators of soil quality and soil management.
Therefore, the need to conduct environmental risk assessment on them is very vital and essential.
Earthworm niche groupings: The orange lines represent the types and depths of the various
burrows.
Study Design
- The study design is according to ISO 11268-3:2014 and ISO 23611-1:2018(E).
- The experimental design is a dose response with three treatment groups; a negative control (water treated control), a positive control (reference
substance) and the test item. - The test is designed as a randomized complete block with at least four replicates for each treatment (10 m * 10 m per plot), with at least 3 m distance between each plot.
Earthworm experimental field design
Sampling
Earthworms are sampled from the soil by combining two different methods:
1. Hand-sorting
2. Allyl-isothiocyanate (AITC) extraction
Identification
- Adults and young worms are counted separately.
- Adult earthworms are identified to species level.
- Young worms which are difficult to identify, a distinction between tanylobous and epilobous is made.
End Points
The following measurement endpoints are obtained:
- Abundance: Number of individuals per area or volume.
- Biomass: Fresh or dry mass of the earthworms per area or volume.
- Dominance ratio (in percentage of the population).
The results are carefully evaluated for possible differences between the
control, test and reference item treatments.
