Earthworm research offers real potential for better soil assessment

Hill Labs from Hamilton have introduced a new test to detect earthworm eDNA levels in soils, marking a significant development in soil health assessment. 

The test, developed in collaboration with AgResearch, is a New Zealand first and represents the beginning of an array of potential applications to provide real benefits across the agricultural sector. 

“Earthworms are often seen as indicators of healthy soil because they need good soil conditions to thrive,” Hill Labs said  this week. 

“They also aid in aeration and nutrient mixing. 

“In high-quality soil, a typical New Zealand paddock would usually have earthworm populations exceeding 400 per square metre and 250 per square metre in arable land.” 

Hill Labs’ earthworm eDNA test measures environmental DNA (eDNA) – tiny traces of genetic material left behind as earthworms move through the soil. 

“Existing methods to assess earthworm populations are labour-intensive and require specialist knowledge, limiting the number of samples and convenience.” 

“A typical field visual assessment involves digging down about 20cm with a spade, then taking a second slice about 35cm away to get a clear sample,” Hill Labs said. 

The soil is broken apart with all worms picked out, counted and the species identified. 

“The new eDNA test, used in tandem with existing field visual assessments, offers a convenient way to enhance soil health monitoring.” 

Hill Labs founder and executive director Dr Roger Hill, who has played a large role in developing the test, said soil remained “the foundation of all life, essential for productive farming, healthy plants and clean waterways”. 

“Our new earthworm eDNA test gives farmers an additional tool to better monitor soil health, helping to promote sustainable farming in New Zealand and beyond. 

“The biological component of soil health is difficult to measure and measuring earthworms provides a high-level view of a soil’s biological health ... and this successful earthworm eDNA soil test is just the beginning,” Hill said. “We’re dedicated to exploring the full potential of this technology across different crops and farming methods.”