Project Raumatatiki
As rain bucketed down on their Marlborough vineyard in May, Bridget Ennals and Steve Pellett pulled on gumboots and coats for a stroll around the vines.
In 2024 Hill Labs introduced New Zealand’s first earthworm environmental DNA (eDNA) soil test, using quantitative PCR to measure tiny traces of genetic material left behind as earthworms move through the soil.
The molecular technology measures the abundance of the shallow-burrowing Aporrectodea caliginosa, which makes up 70-80% of the total earthworm population of New Zealand soils.
Erin McIlmurray, Hill Labs’ Market Sector Manager, Agriculture, says earthworms need healthy soil conditions to thrive, so are an important indicator of soil health.
“Often referred to as the ecological engineers of soil, earthworms contribute to the aeration and cycling of nutrients in soil, as well as helping create good soil structure and breaking down organic matter.”
The eDNA test was developed for pastoral soils, in collaboration with Dr Nicole Schon, an AgResearch senior scientist and leading earthworm specialist, who provided “invaluable background and guidance”, Erin says.
The research team believe it has equal application in viticulture and horticulture, with calibration work underway to relate the eDNA levels to earthworm numbers in the deeper soil core used in viticulture.
Winegrowers collect soil samples as they would for a soil fertility test, with the optimum time during winter to mid spring, when earthworms are more active, and ideally the same time each year, to enable comparisons.
The test complements a visual soil assessment (VSA), Erin says.
“VSAs can be labour intensive and require specialist knowledge. This test provides an easier alternative and another tool in the toolbox for monitoring soil health. The fact that it can be performed on the same sample that is taken for assessing soil fertility is a definite benefit.”
Hill Labs founder and executive director Dr Roger Hill, who has played a large role in developing the test, says it is just the beginning.
“We’re dedicated to exploring the full potential of this technology across different crops and farming methods to support New Zealand’s farmers and growers.”
Our Land and Water provided funding for the initial stages of development of the eDNA test.
