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| Map courtesy of Cittavino |
Sunday, October 10, 2021
Idda: The Gaja-Graci Mt Etna joint venture
Wednesday, October 6, 2021
Throwback: Vineyard visit and lunch at Masseria Setteporte (Biancavilla, Mt. Etna), source of a portion of the land that comprises the Gaja-Graci Idda joint venture
| Piero (top middle) along with Brandon Tokash and Benjamin North Spencer (New Wines of Mt. Etna) |
Sunday, October 3, 2021
Trees in the vineyard (Agroforestry) and the impact on soil-based nutrients
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| Source: Compiled from LGRGP.org and others |
Sources
Rocks
The earth is made up of varying proportions of the 90 or so naturally occurring elements but, according to Alex Maltman (Vineyards, Rocks, & Soils), four of these -- oxygen at 48%, silicon at 28%, aluminum at 8%, and iron at 6% -- are responsible for 88% of its composition. In most geological materials, these elements combine to form minerals -- "a naturally occurring combination of specific elements that are arranged in a particular repeating three-dimensional structure or lattice" (opentextbc.ca, Minerals and Rocks).
In nature, minerals are found in rocks "and the vast majority of rocks are composed of at least a few different minerals." Jackson (Wine Science: Principles and Applications) stipulates that (p. 245) "... the mineral content of soil is primarily derived from the parental rock substrate." The figures below show the weathering of rocks into minerals.
Decaying Organic Material
Jamie Goode (Rescuing Minerality) contends that the bulk of soil mineral content comes "from decaying organic material, not decomposed rock and it is microbial activity in the soil that affects the ability of soil to break down organic matter into mineral ions that can be used by the plant." Maltman agrees with Goode: "... in practice, it's the humus that's more important, indeed essential."
Atmosphere
According to Schwarcz and Schoeninger (Stable Isotope Analysis in Human Nutrition, Yearbook of Physical Anthropology 34, pp. 293-321), almost 100% of exchangeable nitrogen is found in the atmosphere or dissolved in the world's oceans and is transferred from these environments into the biological system through the terrestrial nitrogen cycle.
Cation Exchange
Soil-based nutrients are resident either in the soil solution (water and dissolved minerals in the soil pores) or in the soil matrix (mineral particles and organic matter). Two problems present themselves, however: (i) the concentration of nutrients in the soil solution is low and (ii) the nutrients resident in the soil matrix are immobile. Plant roots have developed adaptions to allow growth into the soil matrix and capture of the nutrients needed for metabolic activity (Dr. Paul Schreiner, USDA-ARS) and we will discuss these later.
The Effect of Trees on Vine Nutrition Parameters
- Agroforestry systems have the potential to increase this material by 50 to 100%
- They return an average of 7.4 tons of organic matter/ha/year in the form of prunings
- They also produce organic matter through litterfall, root slough, and root exudates
- Nutrients that take the form of organic matter are released slowly at rates comparable to rates of plant absorption
- They also present in a stable molecular form that is resistant to leaching
- Organic matter produced by trees serves as a source of food for microbes
- Results in increased microbial populations (by as much as 30%)
- Microbes excrete enzymes that mineralize nutrients, stabilize carbon and N in the soil, and decompose organic matter into simple, plant-available forms
- Results in higher plant nutrient uptake
- Results in increased cation exchange capacity
- Translates to a greater ability of soil to hold onto exchangeable cations
- Better retention of applied nutrients
- Resistance from nutrient leaching
- Nutrients that take the form of organic matter are released slowly at rates comparable to rates of plant absorption
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Source: http://tolweb.org/notes/?note_id=3920 |
- Agroforestry systems increase soil organic by as much as 100% with as little as a 10% increase decreasing soil erodibility by between 13 and 23%
- Litterfall increases ground cover which reduces runoff and erosion
- Surface mulch associated with agroforestry systems reduces the kinetic impact of rainfall, retaining the soil surface structure.
Thursday, September 30, 2021
Regenerative Agriculture and Agroforestry: The effect of trees on water parameters in the vineyard
- stunt vegetative growth
- reduce fruit quality
- completely suppress fruit production
- yield expensive water bills in the cases where irrigation is practiced
- dry up the groundwater.
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| Soil matrix cross-section (Source: serc.carletoon.edu) |
Stage | Effects |
Bud Break |
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Post-Berry Set |
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Post-Fruit Set |
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Post-Harvest |
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- reducing the number of bunches per vine
- reducing photosynthesis (reduced leaf area and increased stomatol closure yield lower berry sugar levels)
- reducing both fruit and vegetative growth
- negatively affecting sugar metabolism and flavor development.
- For a given berry size, vines grown with low irrigation have a higher anthocyanin concentration (between 15% and 33%) than those grown under higher irrigation conditions
- There is a higher concentration of skin tannins in low- versus high-irrigation environments
- Water deficits result in lower yields which, in turn, results in lower veggie characteristics and fruitier wines.
- Improve wine quality by increasing the sugar:acid ratio, lowering malate and total titratable acid concentrations, and increasing total soluble solids
- Increase grape phenological profiles
- Increase sugar concentration in berries
- In a study comparing the effects of 25%, 50%, 70%, and 90% soil moisture regimes, the 25% regime was found to produce the smallest berries and the highest concentrations of sugars and phenological compounds.
Tuesday, September 28, 2021
Piccolo Derthona: A Colli Tortonesi Timorasso entry point for the impatient
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| Piccolo Derthona wines currently produced in Colli Tortonesi (Picture courtesy of Conrad Mattern) |
- Hand-harvesting
- Maceration on the skins in concrete vessels for 48 to 60 hours without sulfuring
- Soft pressing
- Fermentation with indigenous yeasts in stainless steel tanks (20 - 25ºC)
- Spontaneous malolactic fermentation after temperature reduced to 10 - 18ºC
- Wine aged in stainless steel tanks for one year (with batonnage)
- Light filtration prior to bottling
- Minimum 6 months bottle aging.
Sunday, September 26, 2021
Regenerative Agriculture: Agroforestry for improved soil health and as a foil against climate change
Although the story varies greatly from one place to another, the practice of maintaining or integrating trees in the agricultural landscape has existed from ancient times around the world and has constituted the default practice in terms of land use management. It was only during the last centuries that farming and trees became disassociated as monocropping became more common, in an effort to intensify food production.
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| Alley cropping (Source: yaleclimateconnections.org) |
Existing studies reveal that the presence of trees in vineyards imparts a neutral to positive effect on parameters surrounding grapevine water status and water stress despite competition, due to trees’ ability to reduce evaporation and transpiration, modify the microclimate, and distribute water through hydraulic lift. Studies show that trees likely have a slight negative effect on grapevine nutrient status within 4 m of trees; however, trees also have been proven to significantly improve vineyard soil quality. Trees may also potentially increase vine rooting depth and density by improving soil structure and inducing root plasticity. Overall, the positive below-ground services that trees provide in vineyards, paired with the ecological and cost-saving benefits that trees impart to a viticultural ecosystem as a whole, might very well balance out these negative effects.
The existing research on integrated pest management in vineyard agroforestry systems demonstrates the effectiveness of utilizing agroforestry to create heterogeneous vineyard landscape designs as a way to combat pests and diseases. Monocultural vineyard designs are associated with numerous pest management issues that leave vineyards vulnerable to losses, dependent on pesticides, and economically less-resilient. Creating diverse vineyard agroforestry systems by incorporating trees into vineyards has been shown to benefit insect pest management efforts by providing habitat for natural enemy insects and vertebrates, which results in increased abundance of natural enemies, increased parasitism rates, reduced insect pest pressure, and subsequently, reduced yield losses. Although vineyard agroforestry systems can cause increases in pest insect abundance as well, the existing literature shows that the accompanied increases of natural enemy populations result in overall increased insect pest control and reduced herbivore damage. Vineyard agroforestry systems may also control bacterial and viral infections by controlling the insect vectors that transmit these pathogens, however, great care must be taken to avoid intercropping grapevines with trees that could be hosts for harmful viral and bacterial vectors. The prevalence of fungal infections in vineyard agroforestry systems may be increased by the increased shade that trees impart, but may be reduced by trees’ windbreak effects and by the beneficial reductions 52 in vine vigor that occur as a result of below-ground competition between trees and vines. The presence of trees in vineyards also facilitates the proper timing of precision pesticide applications by slowing wind and creating conditions conducive to pesticide application at the precise moment when pest pressure is at the proper threshold.
The presence of trees in vineyard agroforestry systems impacts light patterns, which, in turn, affect wine grape physiological, production, and quality parameters in both positive and negative ways. Trees reduce the quality and quantity of light that reaches understory crops, trees reflect light from their canopies onto understory crops, and tree shade reduces temperature ... In wine growing regions impacted by high temperatures and more frequent heat waves, shade from trees may benefit grapevines by reducing sunburn from UV radiation, maintaining photosynthesis rates, preventing yield losses from shriveling, maintaining adequate sugar levels, preventing acid degradation, allowing anthocyanin development, and promoting synchronized development of flavor profiles for an overall balanced and high-quality wine. In wine growing regions that are less impacted by climate change, shade may have opposite effects, and may reduce levels of SS, acids, anthocyanins, and yield. In all regions, regardless of the predicted impact of climate change, shade is speculated to have a negative impact on flavonols and long-term anthocyanin stability.
As regards microclimate:
Trees benefit vineyards by positively affecting wind patterns and the viticultural microclimate. Although incorporating trees into vineyards can increase management complexity, can reduce yields nearest to trees, and can negatively affect certain grape quality parameters, research suggests that the many above-ground benefits of vineyard agroforestry may very well outweigh their costs. The positive above-ground services that trees provide, such as preventing wind damage and erosion, increasing stomatal aperture and leaf area, increasing photosynthetic capacity, protecting against heat, protecting against frost, and reducing water stress suggest that vineyard agroforestry systems may be a wise solution to the many problems facing modern viticulture, especially considering the extreme temperatures, weather events, pest and disease pressure, and micro- and macro-climatic shifts that are predicted to come in the following years with climate change.
Sunday, September 19, 2021
Corsica's Corse-Calvi AOC, the grape source for Etienne Suzzoni's Clos Culombu Blanc
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| Corsican wine regions (Wikipedia) |
- Extremely sandy soils in the foothills
- Increasingly loamy -- sometimes even clayey -- soils in the plains.














