Chapter 8 - Part 1: Hazards Flashcards
Drought management
- Irrigation esp in initial vineyard design
- Using drought resistant rootstock ie 110R, 140R
- Growing drought resistant varietals ie Grenache
Excess water management
- Constructing a drainage system
- Planting on a slope
- Planting on free draining soil
- Using water-log resistant rootstock
Untimely Rainfall management
- Nothing you can do at the moment but during vineyard establishment, if you know that the area is prone to high volumes of rainfall, you can plant on a slope, on free draining soil, put in a drainage system
- You can closely monitor the weather forecast and consider harvesting earlier (if this is during harvest month)
Freeze management - site selection
- Plant on hillside sites rather than valley floor
- Plant near a body of water
- Plant where snow settles most thickly as it can provide insulation
Freeze management - choice of varieties
- Plant more winter freeze resiliant varietals (cab franc, riesling)
- Plant hybrids with v. amurensis (an american adn mongolian species). It is very hardy and can withstand temps down to -30C
Freeze management - protecting vines
- Build up soil around the vine graft to help insulate the vine (the graft is the most at risk part of the vine)
- burying the vine - but exztremely expensive
- Prune vines to have several trunks to if one dies, it can be replaced
2 types of frost
- Advective frost - caused by large volumes of cold air moving in from very cold areas
- Radiative frosts - caused by heat being lost on still, cool nights as the cold air collects just above the surface of the soil (common on valley floors)
Frost management - When frost threatens
- Water sprinklers - when water freezes, laent heat is released. ONLY method that works against advective frost
- Wind machines - works if there is warm air above
- Oil or propane gas burning heaters and wax candles. However, fuel and labor cost is high. Also pollutes the air
Frost management - Reducing the risk
Frost occurs when cold air below 0C collect at ground level. Freezes the water in teh vine’s growing buds and shoots
- Train the vines higher off the ground
- Pruning later in the winter - delays budburst
- Choose to plant on hillsides and avoid frost pockets
- Choosing a late budding varietal like Riesling
- Having bare soil between the vines rather than cover crops - bare soil absorbs heat better
Hail management
- Netting - can only be used in areas with high sunlight though as netting causes shading
- Shooting rockets into the thunderclouds and seeding them with silver iodide to cause rain to fall instead of hail
- Plant many plots to diversify risk (hail is very localized)
- Buying crop insurance
Sunburn management
This happens because grape transpiration is less efficient than leave transpiration and so grapes reach higher temps. Worse when the vines are already water stressed
Leads to browning, bitter taste, and inc susceptibility to rot
- Shading
- Row orientation and aspect consideration during vineyard planning (avoid east/west orientation)
- Irrigate, if possible
- Special agricultural sunscreen spray or netting
Fire management
Cover crops and mulch provide fuel to fires. Fires spread less easily on bare, cultivated soils
Install fire detectors and sprinklers
Install and maintain a water tank
Provide employee traning for action in the event of an emergency
Smoke taint
Worse effect on fruit if happens during or after verison - the smoke binds with sugars and form aroma-less precursors
- Test affected musts analytically or by micro-vinification in the days leading up to harvest to establish the exztent of the problem
- Avoid skin contact/fermentation - hand harvesting, whole bunch pressing, low ferm temp, reduced maceration times (bc smoke aroma precursors are present on the inside of the skin of the grapes
- Flash detente and reverse osmosis can help but not completely remove
