03/11/2024
Earthworms as Indicators of Soil Health
Earthworms are the most common indicators of high-quality soils, as they’re visible to the naked eye. But what roles do they actually play? Earthworms actively modify soil structure by creating new aggregates and pores. This not only enhances soil tilth, aeration, infiltration, and drainage but also promotes root growth. Additionally, earthworm castings are nutrient-rich, which significantly contributes to soil fertility.
There are three main groups of earthworms, classified based on their habitats:
1. Litter Dwellers: These earthworms live in plant litter and feed on plant residue. They are absent in ploughed soils where plant litter is not present.
2. Mineral Soil Dwellers: Found in organic matter-rich topsoils, these worms create burrows as they feed on a mix of soil and plant residue.
3. Deep Soil Burrowers: These earthworms dig large, deep channels into lower soil layers, carrying plant residue with them as they feed.
Key Factors Affecting Earthworm Populations
Earthworm health and population are influenced by:
• Seasonal and climate variations
• Soil moisture, aeration, texture, and temperature
• Amount and quality of plant residue
• Soil pH
• Fertiliser application
• Fungicides
• Low Earthworm Populations
If you observe low earthworm populations in your soil, this often indicates minimal organic matter, elevated soil temperatures, or low moisture levels. In such cases, the soil’s nutrient cycling, drainage, and aggregate stability may be compromised. You can improve conditions by practicing no-till, incorporating legumes and cover crops, applying manure, managing pH, and adjusting irrigation and drainage.
Consult your Kynoch Agriculturist for guidance on enhancing soil quality and understanding its impact on crop yield and quality.
Compiled by: Lunay de K**k, Kynoch Fertilizer
Source: Soil Biology, UFS, 2021