From waste to the land: Reuse vineyard waste as compost | Local news


Napa County winemakers are constantly looking for innovative ways to reduce waste while increasing the productivity of their vineyards, but not all of these methods are high tech or brand new. For many, the act of accumulating, turning and spreading compost is a fundamental but essential part of their vineyard management strategy, and has been practiced ever since ancient civilizations prioritized agriculture.

“Composting has always been seen as the key to better agriculture and is a key practice used in Napa Valley wineries,” said Michael Silacci, Winemaker for Opus One and President of the Napa Valley Grapegrowers. “When composting is done correctly using good management techniques and temperature control, the result is a good source of nutrients for the plants and it has a positive impact on preventing soil erosion by rebuilding the soil. soil structure and supporting plant growth. “

By increasing the microbial activity of this waste – think oak leaves, grape stems, manure – extracted from their property, wine growers are able to not only improve soil health, but also conserve as much of the soil. waste on site as possible.

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“The mission of the Napa Valley winemakers is to preserve and promote the world-class wineries of Napa Valley, [and] the watermark that hangs behind this statement is to protect. Given the impact of climate change on Napa Valley, it is imperative to go beyond simple recycling to reuse, ”said Silacci.

The actual distribution of what winemakers choose to compost varies from year to year and from vineyard to vineyard, but it is usually a mixture of different organic plant and animal wastes. According to Gustavo Avina, director of viticulture at Pine Ridge Vineyards, the ratio of plant and animal waste directly correlates to the types of nutrients that will be distributed on the property and therefore differs depending on growing conditions.

“For example, vine-based compost can be high in potassium and some heavy types of manure can be very high in nitrogen,” Avina said. “On the same note, poorly produced and poorly produced animal-based compost can be rich in salts… The quality of the compost is the driving force here, as both types of compost are invaluable tools in viticulture.”

In addition to the differences in the composition of the materials, there are also different methods of spreading compost. Some winemakers prefer compost teas – made by literally brewing a bag of compost in water – so they can apply compost the same way as irrigation, while others opt for physical spreading. solid matter on the ground and its incorporation by discarding or other intervention.

“For existing vineyards, I really prefer compost tea, [because] it goes straight to the root zone and it starts working right away, ”Avina said.

Since Pine Ridge started using compost tea, Avina estimates that she has reduced her water use by almost 40% and that the canopy of her vines has improved significantly.

“In addition, we have also observed a dramatic improvement in the way the vines handle heat events,” said Avina. “The point is that many wineries that we buy from that do not use tea injections have more shriveling, leaf burns, damage from exposure to clusters such as rosettes or stroke. pinkish sun, and in some cases, canopy collapse. “

However, for vineyard development, Avina suggests solid compost as you can add it as the soil needs.

At Seavey Vineyard, Fred Seavey and the rest of his team take it a step further by incorporating biochar into their compost. In addition to a mixture of manure from the estate’s goats and sheep, grape skins and fallen leaves, Seavey also burns dead vines and other woods to capture carbon in the vineyard.

“The Napa RCD taught us how to do the burns in a way that produces this biochar so that we can recycle it in our compost and in our soil,” Seavey said. “By heating it in the absence of oxygen, you turn all that material into almost pure carbon, and then you can put the carbon in the soil.”

Using biochar in this manner thus sequesters carbon – in turn mitigating climate impacts – as Seavey would otherwise have to ignore or burn any fallen wood or dead vines on the property.

“If we were to just leave the wood on the forest floor, it would eventually decompose and decompose and send that carbon back to the atmosphere as CO2,” Seavey said. “It also improves the water-holding capacity of the soil, which makes us more drought tolerant, and helps us to be a place of microbial life. “

In general, while wine growers use compost in slightly different ways depending on their soil needs, property size, or even rainfall, the general consensus is that reusing this waste is a benevolent act, which could also lead to to a more delicious wine.

“The more we do to isolate a vineyard’s inputs, the more authentic the reflection of the place,” said Silacci. “Allowing the wild yeast from the vineyard to ferment the grape juice, using composted materials from the vineyard, and understanding the site all lead to a greater sense of belonging to the wine.”

The proposed Walt Ranch vineyard project in Napa County remains a controversial issue and has sparked a recent protest.

You can reach Sam Jones at 707-256-2221 and [email protected]


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