Nick Paulin: Crimping, Cover Crops & the Undies Test

Nick Paulin: Crimping, Cover Crops & the Undies Test 2560 1709 Sectormentor

Regenerative Viticulture Series #7
Abby Rose in conversation with Nick Paulin

Nick Paulin, a creative viticulturist from New Zealand, joins Abby Rose in conversation. They discuss the successes and pitfalls of implementing regenerative techniques on the ground. 

Nick has been the Estate Manager of AONZ Vineyard and Fine Wines since 2017, gradually starting to experiment with regenerative techniques since then. This shift at the vineyard has led to significant innovations in their viticulture practices, particularly in subsurface irrigation, cover cropping, and crimping. Nick describes this three-pronged approach as the key to healthy soils and vines.

Key Takeaways:

Subsurface Irrigation

After observing impressive results from a local vineyard, subsurface irrigation became a new experiment for Nick and the team at AONZ. They implemented a copper-featured system designed to prevent roots from penetrating irrigation lines. Although it took a full season to see the benefits, the vineyard’s resilience to the summer months improved dramatically; both grass and cover crops survived, keeping soil activity alive even in dry conditions. The vines adapted by extending roots toward the irrigation lines in the centre of the rows, sitting comfortably underneath a carpet of rich cover crop. Despite initial fears of leaks, the system proved effective, with leaks easily identifiable by patches of squelchy ground or overgrown foliage.

Cover Crops

Nick’s cover crop strategy started with a basic two-species mix, evolving to a current 12-species blend, including grasses, brassicas, legumes, chenopods, and cereals. This mix, tailored by a seed supplier, has performed well across various vineyards owned by AONZ. Cover crops are re-seeded every two years, as trials undertaken by Nick have shown effectiveness diminishing after this period. Full cultivation is used to establish the crops, with autumn sowing yielding the best results due to warmer soil temperatures. This approach not only accelerates crop establishment but also enhances soil organic matter, as shown by a 0.5% increase in organic matter in cover-cropped rows compared to grasses-only rows.

Crimping over Mowing

Crimping has become the preferred method over mowing for Nick. Although initial results can be mixed, consistent crimping (repeated four or five times over the season) encourages the clover to thrive as larger plants are rolled down. This technique helps manage the cover crops effectively, reducing the need for mowing which Nick has found to negatively impact soil health. Crimping undervine, Nick elaborates, can also keep undervine weeds under control. 

The Undies Test

Nick has been keeping track of the soil health of the vineyard for many years now. He likes to carry out frequent ‘undies’ tests, involving burying a pair of cotton underpants to later dig up. The state of degradation of the underpants will reflect microbial activity in the soil, and therefore soil health. Nick carried out this test in two vineyard blocks, one with a grasses mix and the other with Nick’s diverse cover crop mix. They found that the underpants from the block with the cover crop mix had biodegraded significantly more than the underpants buried in the block with a simple grasses mix. This was a ‘lightbulb’ moment for Nick and the team, because they could see the tangible differences in soil health between blocks, depending on the plant diversity.

The combination of subsurface irrigation, cover cropping, crimping and soil testing has proved a success for Nick and the team at AONZ. These practices have led to the production of smaller, more concentrated grapes, enhancing flavour concentration and reducing the risk of water-diluted fruit. The vineyard has also seen impressive yields from 5 and 6 year old vines. Through these regenerative techniques, Nick and the team have cultivated a sustainable and thriving vineyard.

Thank-you to Nick for joining us for our first episode of this years installment of the Regenerative Viticulture Series!