The Vineyards at Dodon – Healthy soils to sequester carbon in vineyards
COMPANY SUMMARY:
The Vineyards at Dodon is a family-owned vineyard and winery producing Sauvignon Blanc, Chardonnay, Merlot, and Cabernet Sauvignon-driven wines on the western shore uplands of the Chesapeake Bay.
Dodon relies largely on ecological methods to manage its 6.4-hectare vineyard. Mycorrhizal fungal populations are encouraged by diverse perennial grasses and forbs supplemented with annuals to address specific challenges between and within vine rows. Compost is produced on the farm in a static aerobic system that relies on ramial wood chips inoculated with indigenous microorganisms. Dormant pruning wood is mulched in situ, and sheep and chickens are grazed within the vineyard during the winter. Tall cover crops are terminated at bloom using a custom roller-crimper, and no herbicides are used.
These regenerative practices in the vineyard are complemented by highly diverse plantings of native grasses, forbs, hedgerows, and forests adjacent to the vineyard. These pollinator “sanctuaries” provide protected breeding and overwintering habitat for natural predators and parasites of insect pests. Taken together, these agricultural methods allow Dodon to reduce pesticide use and tractor passes while improving plant health and resilience, and wine quality.
ABSTRACT
Healthy soils – those that function as a vital living ecosystem – have been shown to enhance water infiltration and holding capacity, reduce microbial pathogens, weeds, and herbivory, and improve plant health in agricultural systems. Soil organic matter is both a foundational component and an indicator of soil health, and because it stores three times more carbon than the atmosphere, increasing soil carbon content by even a small percentage represents a substantial mechanism to reduce atmospheric carbon dioxide and reverse global warming. The objectives of this ongoing project are to apply agroecological principles to:
(1) increase soil organic matter,
(2) enhance above and below ground ecosystem services,
(3) reduce pesticide use, and
(4) improve wine depth, longevity, balance, and harmony.
STARTING DATE: — | ENDING DATE: ongoing
SUSTAINABLE TARGET
Ecosystem resilience and regeneration, carbon sequestration
REASON WHY/ MOTIVATION
Carbon pollution, warmer temperatures, and changing weather patterns make winegrowing difficult in the mid-Atlantic region of the United States. For example, following heavy rain during the 2018 harvest, we were unable to produce red wine from our vineyard. Regenerative agricultural practices, such as no-till and diverse cover crops, can capture atmospheric carbon and store it in soil, make crops healthier and farms more resilient, and help address climate change.
DESCRIPTION and STRATEGIES
Soil with structural integrity, a diverse microbiome, and high levels of organic matter carry out many vital functions. It provides essential support for plants, protects against both drought and flood, removes environmental toxins, and improves water quality. Particularly important in today’s world, soil stores large quantities of carbon – more than twice the amount found in the atmosphere. Putting more carbon in soil will play a crucial role in addressing the underlying cause of climate change.
To achieve these goals, we embrace the core practices of regenerative agriculture – disturbing the soil as little as possible, maintaining diverse perennial plants throughout the year, and integrating livestock using holistic grazing techniques. We have done so in the context of the overall landscape of our farm which includes 400 acres of natural areas and riparian buffers, 120 acres of pasture and cropland, and extensive hedgerows and meadows of native grasses and forbs that provide sanctuary for beneficial insects.
Because different plants provide diverse nutrients to soil microbes, we enhance plant diversity within the vineyard using perennial cover crops supplemented by various annual grasses and forbs selected to address specific challenges such as compaction and plow pan. Instead of mowing, we use a custom-made roller-crimper. Crimping inhibits the hormonal signals that stimulate regrowth and terminates the growth of tall species while allowing low-growing varieties to flourish. It also adds a mulch layer that cools the soil, creating an optimal environment for fungal growth.
Reasoning that grapevines would likely be healthiest in a forest-like setting supported by nutrients and microbes that are common in that ecosystem, we emphasize growth of diverse fungal species that prefer woody food sources. Dodon’s compost program uses ramial wood chips that result in high carbon to nitrogen ratios of about 40:1. While most compost is produced in windrows that require regular turning, we have also constructed a static, aerobic composter inoculated with soil from the woods just outside the vineyard. We believe that this system encourages native mycorrhizal fungal species that will interact with the vines to produce better soil, healthier plants, and better fruit.
ACHIEVEMENTS SO FAR
CO2 SEQUESTRATION BY SOIL ORGANIC MATTER INCREASE:
Between 2012 and 2019, soil organic matter in the vineyard increased from 0.3% to 2.8%, raising soil organic carbon stocks by 44 tons per acre to a depth of 18 inches. Across the 16-acre vineyard, we can estimate that about 2,550 tons of carbon dioxide have been sequestered and stored over seven years.
Reduction the use of insecticide:
We have improved vineyard water infiltration, eliminated mowing and herbicide use, and reduced annual insecticide use by 70-100% depending on the vintage.
Nitrogen content:
Grape must acid balance has trended toward optimal levels, reducing the need for acidification. We have not observed changes in vine vigor, but yeast assimilable nitrogen has declined from 75 mg N/L to 44 mg N/L, suggesting that the increase in soil carbon is associated with declines in plant-available nitrogen and may require additional legumes and other nitrogen-fixing species in the cover crop.
LESSONS LEARNED
Ecosystem restoration is not a straightforward process. Rather it requires perseverance and experimentation.
For example, because of competition from existing perennial cover crops, we have not yet determined the best time or method to plant supplemental annuals. Because of persistent seed banks of undesirable plant species such as Johnson grass (Sorghum halepense), horseweed (Conyza canadensis), and dock weed (Rumex spp.), establishing and maintaining the pollinator meadows has taken the constant effort to maintain desirable species.
