3rd Edition of Agriculture, Forestry, and Horticulture World Conference 2027

Abstract

Background
Soil degradation is recognized as one of the most pressing global environmental issues, reducing agricultural productivity and threatening food security. Heavy metals, unlike many organic pollutants, do not degrade over time, making their accumulation in soils a long-term challenge. Earthworms act as bioindicators and ecological engineers in soil remediation. Their sensitivity to pollutants enables heavy metal bioaccumulation and reduces contaminant mobility. Through burrowing, feeding, and life cycle activities, they restructure soil environments, stimulate microbial growth, and enhance bioremediation efficiency. Soils face increasing pressures from climate change, land degradation, and biodiversity loss, while heavy metals remain persistent pollutants threatening ecosystem stability and human health. Soil biodiversity, particularly earthworms, plays a critical role in nutrient cycling, organic matter decomposition, and resilience.
Methods and Study 
Georgia, within the Caucasus biodiversity hotspot, hosts about 90 earthworm species across 13 genera, more than half endemic, providing a unique baseline for ecological studies. Experimental evidence shows species-specific differences in heavy metal accumulation: Aporrectodea rosea, Eisenia veneta, and Allolobophora chlorotica retain varying amounts of copper, zinc, and lead, with larger individuals accumulating more zinc and releasing metals differentially in clean water.
Complementary studies focused on Eisenia andrei populations isolated in Georgia. Eisenia andrei was selected as a model species due to its adaptability and widespread use in vermicomposting research, making it ideal for assessing substrate effects on growth and reproduction. During experiments, worms were adapted to different substrates for food, including cattle manure and poultry litter. Significant differences were observed in growth rates and reproductive characteristics, suggesting that substrate selection plays a crucial role in optimizing worm health and productivity.
Findings
The rates of substrate processing, as well as the composition and quality of the produced compost, were compared. In the intestines of earthworms, partial humification of plant tissues and the formation of clay-humic complexes occur, forming the basis of stable humus. Along with plant remains, worms ingest mineral particles and mix them, producing coprolites that are highly water-resistant and contribute to soil structure. Active mixing of forest litter with soil by earthworms leads to the formation of typical forest soil profiles.
The nutrient-rich compost produced by earthworms not only improves soil fertility but also reduces reliance on chemical fertilizers, offering a sustainable alternative for agriculture.
Results showed that particular types of substrates stimulated worm growth and improved the nutrient composition of compost. This emphasizes the importance of selecting appropriate organic ingredients for vermicomposting to maximize worm productivity and the quality of the final product.
Conclusions
Integrating faunistic diversity, bioaccumulation studies, and substrate adaptation experiments underscores the dual importance of earthworms: they serve both as indicators of contamination and as remediation agents enhancing soil fertility. This methodological model links local biodiversity data to broader remediation strategies and demonstrates how experimental findings can inform practical applications in vermicomposting, sustainable agriculture, and waste management.
Future studies could explore optimal substrate combinations and long-term monitoring of earthworm-mediated remediation, providing transferable models for other regions facing similar soil contamination challenges. The presentation highlights how Georgian earthworm diversity and experimental evidence contribute to sustainable soil management and ecological restoration under conditions of climate change and land degradation. By combining biodiversity baselines with applied vermicomposting practices, the research shows how earthworm-mediated processes support resilience, remediation, and sustainability in soil ecosystems.

The study is part of the project “Healthy Soil for Food Safety” [FR-23-268], funded by the Shota Rustaveli National Science Foundation of Georgia.