Winepress - July 2021

GROW

Living Plough Getting to the root cause of soil health SOPHIE PREECE

CONSTELLATION BRANDS is using nature to drive better soil health, with the Living Plough project helping develop a “subterranean ecosystem” at its Fairhall vineyard. Grower viticulturist Mel Pierce has two 7 hectare trials on the 70ha block, with an array of deep rooted cover crops planted in either ripped or drilled soil, to ease soil compaction and increase vineyard health. “The Living Plough trial is to see if you can break up the soil with cover crops as well as you can by mechanical means,” she says, explaining how compacted soils can restrict vine roots to a small area, preventing the plant from fully developing. This also results in less drainage and deep water storage, and increased risk of drought stress between rain events. “So you have starved the vine of oxygen, you’ve starved it of water and nutrients, and you have prevented the flow of all of your organisms,” she says. “If you imagine a vine trying to grow through concrete, that’s what compaction is.”

It essentially means a vine lives like a pot plant, says Constellation Brands New Zealand national technical viticulturist Jeff Sinnott, who compares soil to a sponge that, while compressed, can no longer hold water or nutrients.

Jeff and Mel both joined the company a little over a year ago, and were excited by the prospect of using their technical skills and knowledge to enhance vines and yields at the Fairhall block, which has been through “20-odd years of a little too much taking and not enough giving”, Jeff

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says. The vineyard’s clay subsoils exacerbate the challenge, because they are particularly vulnerable to compaction, especially when tractor passes follow rainfall, evacuating soil aeration and solidifying the sponge. “When we got here, we saw a big opportunity to enhance soil health and in turn increase yield,” says Jeff. “A win-win.”

The duo both come from backgrounds of “precision viticulture” where the process is about give and take, “not take and take”, says Mel, who worked 12 years in the United States, where soil health was a key aspect of a vineyard manager’s role, because of the commercial consequences of its decline. “The vine gets weak, it has weaker shoot growth, it has lower yields. The root systems just can’t develop properly – especially in compacted soils,” says Mel, describing exacerbated issues of pest and disease in unhealthy soils, as well as lower production. “If we can find a way of breaking compaction without turning the soil, that is a huge win.”

The cover crops are not just about changing the physical state of the soil, and Constellation is working with Linnaeus Laboratory to analyse changes in various microbiome dynamics in the soil as the trial progresses. “It is basically creating a self-sustaining subterranean ecosystem,” says Mel. “We look at all the different interactions - how the physical, chemical and biological aspects interact, including parent material, organic matter and the soil microbiome.”