The soil composition of vineyards
is one of the most important viticultural
consideration when planting grape vines. The soil
supports the root
structure of the vine and influences the drainage levels and amount of minerals
and nutrients that the vine is exposed to. The ideal circumstance for a vine is an area of thin topsoil
that sufficiently retains waters but also has good drainage so that the vine roots don't become overly saturated. The ability of the soil to retain heat and/or reflect it back up to the vine is also an important consideration that affects the ripening of the grape.
There are several minerals that are vital to the health of vines that all good vineyard soils have. These include calcium which helps to neutralize the Soil pH levels, iron which is essential for photosynthesis, magnesium which is an important component of chlorophyll, nitrogen which is assimilated in the form of nitrates, phosphates which encourages root development, and potassium which improves the vine metabolisms and increases it health for next year's crop.
List of Soil Terms
Unless otherwise noted the primary reference for this list is Sotheby's Wine Encyclopedia 2005
- Dolomite - Calcium-magnesium carbonate soil.
- Flint - Siliceous stone that reflects and retain heat well. The Pouilly-Fumé wine of the Loire Valley is generally produced on Flint-based soil and is said to have "gun-flint" smell in the wine.
- Galestro - Schist based soil found in the Tuscany region of Italy.
- Granite - Composed of 40-60% quartz, 30-40% Orthoclase and various amounts of hornblende, mica, and other minerals. This soil warms quickly and retains heat well. The soil's high level of acidity works to minimize the acid levels in the grapes which works well with acidic grapes like Gamay. It is the main soil type of the Brand region of Alsace.
- Gravel - Loose siliceous pebble soil that has good drainage but poor fertility. Vines planted in this type of soil must penetrate deeply to try to and find nutrients in the subsoil. Wine made from vines produces on clay gravel beds have less acidity then those planted on limestone gravel beds. The Graves region of Bordeaux and Sauternes is dominated by gravel based soil.
- Greywacke - Sedimentary soil formed by rivers depositing quartz, mudstone and feldspar. It is found in vineyards of Germany, New Zealand and South Africa.
- Gypsum - Calcium sulfite based soil that is formed through the evaporation of seawater. It is a high absorbent soil that has average drainage ability.
- Hardpan - A dense layer of clay that is impenetrable by roots and water. In some areas of Bordeaux, a sandy iron-rich layer is located deep enough below the surface to act as a water table for the vine.
- Keuper - Soil type consisting of marl and limestone common in Alsace dating back from the Upper Triassic period.
- Kimmeridgian soil - A gray colored limestone based soil originally identified in Kimmeridge, England. Kimmeridgian clay is calcareous clay containing Kimmeridgian limestone. This is the principle soil type of the Loire Valley, Champagne and Burgundy regions.
- Lignite - soil type used as fertilizer in Germany and Champagne. It is a brown colored carbonaceous soil that is an intermediate between peat and coal.
- Limestone - Sedimentary based soil consisting of carbonates. The most common colored limestone found in wine producing area is buff-gray in color (with the exception of white chalk). The water retention abilities vary from composition but limestone is consistently alkaline and is generally planted with grapes of high acidity levels. This is the main soil type in the Zinnkoepflé region of Alsace.
- Llicorella - A soil type found in the Montsant region of Spain. The soil is a mix of slate and quartz that dates back to the Paleolithic era. The soil is very porous and drains well. Syrah, Grenache and Carignan have done well in this soil type.
- Loam - Warm, soft, fertile soil composed of roughly equal amounts of silt, sand and clay. It is typically too fertile for high quality wines that need to limit yields in order to concentrate flavors.
- Loess - A silt-based soil composed of wind borne materials that are normally weathered and decalcified. The soil has good water retention and warming properties.
- Marl - Calcerous clay-based soil that is cold and adds acidity to the wine. Vine planted in this type of soil normally ripening later than in other soil types. Marlstone is a limestone based clay that acts similar to Marl.
- Mica - Silicate based soil composed of fine, decomposed rock formations.
- Muschelkalk -Soil type consisting of various compositions of sandstone, marl, dolomite, and shingle common in Alsace dating back from the Middle Triassic period.
- Perlite - A volcanic soil type that is light, powdery and lustrous in characteristic with properties similar to diatomaceous earth.
- Quartz - Common material found in most vineyard soils-especially sand and silt based soils. The high Soil pH of quartz can reduce the acidity of the resulting wines but its heat retaining properties that stores and reflect heat can increase ripening of the grape which normally results in wine of higher alcohol content.
- Sand - warm, airy soil that is composed of tiny particles of weathered rocks. One of the few soils that the phylloxera louse does not thrive in, the soil drain wells but does not have good water retention. Sandstone is a sedimentary soil composed of sand particles that has been pressured bound by various iron based minerals. This is the main soil type of Kitterlé in Alsace.
- Schist - Laminated, crystalline rock based soil that retains heat well and is rich in magnesium and potassium but is poor in organic nutrients and nitrogens.
- Shale - Fine grain sedimentary based soil that can turn into slate when under pressure. The soil is moderately fertile and retains heat well.
- Siliceous soil - Soil composed of acid rock that are crystalline in nature. The soil has good heat retention but needs the added composition of silt, clay and other sedimentary soils to have any kind of water retention. The range of this soil can include organic materials like Kieselguhr and flint or inorganic materials like quartz. This soil type covers half of the wine regions of Bordeaux.
- Silt - Soil type consisting of fine grain deposits that offer good water retention but poor drainage. It is more fertile the sand.
- Silex - A flint and sand based soil type found primarily in the Loire Valley that is a formed from a mixture of clay, limestone and silca.
- Slate - Soil type that is the most common found in the Mosel region that is a dark gray, plate like rock that formed when clay, shale, siltstone and other sediments are subjected to pressure. The soil retains heat well and warms up relatively quickly.
- Steige - A schist based soil found in the Andlau region of Alsace. In the Alsace Grand Cru AOC of Kastelberg the soil has metamorphosed with granite sand to form a hard, dark slate like stone.
- Terra Rossa - A sedimentary soil, known as "Red Earth", that is created after carbonates have been leached out of limestone. The breakdown leaves behind iron deposits which oxidizes and turns the soil a rustic red color. This soil type is found in some areas along the Mediterranean and in Coonawarra, Australia. The soil drains well and is relatively high in nutrients. Australian winemakers have found some success with Cabernet Sauvignon plantings.
- Volcanic soil - Soil that is created by one of two volcanic activities. 1.) Vent-based soil is material that has been ejected into the air, cooled and settled to the earth. These include pumice and tufa. 2.) Lava-based soil are the product of lava flows from the volcano. 90 percent of lava-based soil is composed of basalt with the other ten percent including andesite, pitchstone, rhyolite, and trachyte.