Soil Flashcards
Why is soil important for the vine?
It anchors the vine and provides nutrients for growth.
Define soil’s origin and properties.
The result of physical, chemical, and biological processes acting on organic substances and inorganic weathered rock (mineral matter) that accumulate on Earth’s surface.
It is porous, containing water and air.
What are the general proportions of soil components?
40-60%
Mineral Matter
20-50%
Water
10-25%
Air
Remainder
Organic
How has old world winemaking influenced the perception of soil fertility and viticulture?
Experiential learning has shown that stony, low fertility soil with good drainage restricts vegetative growth, warms quickly and radiates heat. The latter attributes are particularly important in cooler, damper environments.
What are the physical properties of soil?
Texture
Structure
Color
Water Availability and Drainage
Air
What are the chemical properties of soil?
Soil Acidity/PH
Nutrient Status
What are the biological properties of soil?
Organic Matter
Humus
Micro-organisms
Organisms
What type of soil can vines grow in?
A wide range that can be ameliorated to provide sufficient nutrients to the vine.
What is an important consideration when planting a vine regarding the availability of water, nutrients, etc.?
That the rootstock is appropriate to the soil.
What properties of the soil do texture and structure affect?
Water Availability and Drainage
Nutrient Availability
Aeration
Root Growth
Erosion
Ease of Cultivation
What are common soil particles and their relative diameter, in millimeters?
Clay
<0.002mm
Silt
0.002-0.02mm
Fine Sand
0.02-0.2mm
Sand
0.2-2mm
Gravel / Grit / Stones
>2mm
What is a Colloid?
A particle smaller than 0.001mm (1 micrometer, 1μm)
What is Soil Texture?
A measure of the proportions of inorganic clay, silt and sand that soil contains.
These particles are graded by their size.
What are the classifications of soil texture and their parameters?
Sand: 5% Clay particles
Loam: 25% Clay particles
Clay: 50% Clay particles
Which soils are heaviest and which are lightest?
Clay soils are heaviest.
Sandy soils are lightest.
Which soils are typically preferred for viticulture?
Loam soils.
Which soils hold more water content and why?
Heavy soils due to their high clay or silt content. The smaller particles hold water tightly on their surface..
Which soils hold less water content and why?
Light soils due to their high sand and gravel content. The larger particles create space that allows water to drain freely.
What are the benefits and risks of using coarser soils?
The soil offers good drainage which can benefit vines in damp regions, though whatever water remains is easily accessible. They do not typically retain nutrients. In some places, both water and nutrition can be controlled.
Regarding Microclimate, why is the proportion of clay in a soil important?
1) Clays have a great capacity to bind and hold water and nutrients.
2) Clay particles are negatively charged, so they can hold more nutrient elements (minerals).
3) The water absobed by clay may not be available to the vine.
4) Clay tends to heat up slower in spring and be cooler year round due to its water retention.
Viticulturally, why is the proportion of clay in a soil important?
1) Clay is slippery and expands when wet but shrinks when it dries. This can crack the Clay which forces the water out and could hurt the vine’s roots.
2) Clay becomes sticky when wet, making it difficult to work and drive on with machinery.
3) The structure of clay deteriorates when it is worked.
4) Dry clay soils are hard and solid, making root penetration difficult.
When does the presence of clay best benefit a vine?
When there is a proportion of larger particles to aid aeration and drainage. Mixing Clay with larger particles pushes the soil type closer toward a preferred Loam style.
Describe the characteristics of predominantly Sandy soils.
Coarse textured
Allow easy root penetration
Low nutrition and high drainage
May collapse under excess water
Heat up more quickly in Spring and are generally warmer than Clay soils
Describe the characteristics of soil that is predominantly Clay and Silt.
Fine textured
Impede root growth
High nutrition, water retaining
More stable than Sandy soils
Describe the characteristics of Loam soils.
A largely balanced mix of Clay, Silt, and Sand.
Freely draining with large water retention capacity.
Possess some of the drainage of Sandy soils and a good proportion of the water and nutrient retaining Clay soils.
Fertile and can encourage too much vegetative growth.
True or False
Particles greater than 2mm are excluded from soil texture measurements.
True, though Gravel and larger stones have important effects on soil.
What effects do Gravels have on soils?
In the soil they reduce water retention and improve drainage
On the soil they reduce erosion and aid soil moisture conservation
What effect does Gravel have on Microclimate?
They store heat during the day and radiate it back into the canopy at night.
What is Soil Structure?
The Friability of the soil.
How clay, silt, and sand clump together to form aggregates and how readily the aggregates crumble.
How well the soil forms lumps and crumbs.
What are the characteristics of well structured soil?
Roots can easily penetrate
Water and air can access the soil
Resistant of wind and water erosion
What is a Soil Aggregate?
Groups of soil particles bound more strongly to each other than to surrounding particles. These aggregates form a matrix that creates the overall Soil Structure.
Why is organic matter important to the formation of Soil Aggregates and how does the process work?
Aggregates start to form when Colloidal Clay binds with organic matter such as water, microbial filaments, and organic secretions.
These then bind with silt, sand, and other organic particles to form Aggregates.
What is the effect of organic matter on Friability?
Organic matter improves Friability. The ideal level of organic matter in a soil is 3-10%, considered moderate to high.
What is the ideal level of Friabaility of a soil?
Aggregates up to 2cm that crumble easily increases the rate at which water and air move through soil and subsoil. Roots can also penetrate with ease.
What is the correlation between Friability and the access roots, water, and air have to a soil?
Direct positive correlation.
More Friability means more root, water, and air penetration.
Less Friability means less access as the Aggregates do not crumble easily.
What influences soil structure?
Organic matter
Earthworms and other soil organisms
Wetting and drying
Freezing and thawing
Presence of plant roots
Cultivation and other soil management practices
Texture
Drainage
Compaction
How can the stability of a soil be improved?
The addition of more organic matter
The activity of soil organisms
How do earthworms improve Soil Stability?
They help bind soil particles into stable aggregates
What can poor Soil Structure lead to?
Capping/Crusting: the hardening of the soil’s surface
Puddling: rainwater stays on the soil surface, causing extensive erosion
Sieving: Clay particles are carried down with the water through the soil, sometimes forming a layer that prevents drainage and aeration
Why is it important for air to penetrate into the soil?
The growing tips of vine roots and aerobic soil microbes require oxygen to grow
Why is water penetration important?
Root tips require water to obtain nutrients. Too much, however, will drown the tips and cut off their air supply.
What is Waterlogging?
inadequate drainage that decreases soil aeration, thus restricting root growth and the depth at which roots can reach.
Prolonged waterlogging can kill roots from lack of air.
How does subsoil help vines in regions with dry summers cope with the lack of water?
The roots can tap into water stored in the subsoil late in the season.
What soils are most fertile?
Loamy soils.
Those with a balance of freely draining soil structure and large water holding capacity.
How much water do vines need during the growing season?
500mm (more in hot conditions)
The rate of vine growth in many wine regions is largely determined by what?
The availability of water.
Why is aeration essential in soil?
Provides oxygen to aerobic organisms and suppresses growth of anaerobic organisms
Removes carbon dioxide and other waste gases formed by breakdown of organic matter and by plant roots
Provides roots with oxygen essential for respiration and growth
In what soils can air movement be severely restricted?
Poorly structured clay soils
Heavily compacted soils
Aeration is affected by the ability of the soil to do what?
Drain effectively
What determines a soil’s ability to drain water effectively?
Soil structure and depth of impermeable soil layers
Vines do not grow well on poorly drained soils. Why?
The soils are cooler and take longer to heat in the spring.
They restrict root growth, leading to a reduced resistance to drought and an increased risk of mineral deficiency
How does drainage affect machinery in the vineyard?
Poor drainage reduces the bearing capacity of a soil.
What effect does soil compaction have in the vineyard?
Poor rain infiltration (increased erosion)
Poor soil structure (reduced drainage aeration, and root penetration.
What are the biological aspects of a soil attributed to?
The microscopic and visible organisms that are mostly active in the top 10cm of soil.
From where does the organic matter in soil originate?
Plant and animal remains, secretions, and excretions broken down in the soil by soil organisms.
What are some soil organisms?
Beetles
Mites
Earthworms
Fungi
Bacteria
What is the organic content in soil?
Sugars
Starches
Cellulose
Nitrogenous Compounds
Lignin
Mineral Matter
What organic content is rapidly broken down by soil organisms?
Sugars
Starches
Nitrogenous Compounds
Some Cellulose
What is Humus?
Residual organic matter composed of Lignin, Mineral Matter, and Cellulose not broken down by soil organisms. It decomposes much more slowly than other organic content and forms a significant portion of the soil’s organic material. It is a black or brown colored mixture.
What is the benefit of organic matter to soil?
Increases nutrient availability
Improves water permeability and retention
Makes heavy clay soils more friable
The major water and nutrient storing component of loose, free-draining sandy soils
What benefit does Humus have on soil?
Maintains soil structure by binding particles
Retains available nutrients
High water retention capacity
Small range of swelling and shrinking and easy to crumble
Gradually releases nutrients as the Humus is slowly mineralized
Darkens the color, increasing heat absorption
What are soil layers?
Stratifications of the soil texture and structure over time.
These can be investigated by digging a soil profile, revealing the depth of the layers, their drainage, and any root barriers.
Which soil organisms are considered Macrofauna?
Burrowing vertebrates
Moles, Rabbits, etc.
Which soil organisms are classified as Mesofauna?
Invertebrates
Slugs, snails, nematodes, worms, earthworms, wildlife, mites, insects, centipedes, millipedes
Which soil organisms are classified as Microorganisms?
Algae, Bacteria, Fungi
How do Microorganisms benefit soil?
They break down dead organic matter for their own growth, converting essential elements in organic matter into simple inorganic forms. These inorganic materials are important for the next generation of plants.
What is Mineralization?
The decomposition of chemical compounds in organic matter which are released by Microorganisms as soluble, inorganic forms.
Where does chemical activity occur in soil?
The colloidal fraction, the matrix of tiny clay particles and organic matter.
What are the chemical properties of soil?
Nutrient availability
Soil acidity and pH
What are Macronutrients? Name them.
Elements that plants require in relatively large quantities.
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Calcium (Ca)
Magnesium(Mg)
Sulfur (S)
How does Nitrogen appear in soil?
It is derived from decomposing organic matter and the fixation of atmospheric nitrogen.
How does Phosphorus appear in soil?
It is insoluble and, thus, poorly available. Microorganism activity helps make phosphorus more available.
How does Potassium appear in soil?
It is a constituent if clay minerals. Acidic soils may not have enough, thus requiring fertilization.
How does Calcium appear in soil?
It is found in limestone, typically as particles of Calcium Carbonate.
How does Magnesium appear in soil?
It is more common in loam and clay soils. Magnesium deficiency is more likely in sandy soils.
How does Sulfur appear in soil?
Naturally or by applications in the vineyard.
What are Micronutrients? Name them.
Nutrients that the vine needs in very small quantities.
Iron (Fe)
Manganese (Mn)
Molybdenum (Mo)
Copper (Cu)
Zinc (Zn)
Boron (B)
How does Iron appear in soil?
Iron is present and available in all soils except calcareous soils.
How does Manganese appear in soil?
Clay and Loam soils are typically well supplied with Manganese but its availability reduces as pH increases. Deficiency can occur in lime-rich soils.
How does Molybdenum appear in soil?
It is available in more basic (higher pH) soils.
How does Copper appear in soil?
Rarely deficient due to copper-containing fungicide sprays (Bordeaux Mixture). It is less available in low pH soils.
How does Zinc appear in soil?
It is available in most soils and may be unavailable to vines in calcareous soils.
How does Boron appear in soil?
It is readily available but may be restricted by dry soils.
What depletes the pool of available minerals in soil?
Vine growth
What augments the pool of available minerals in soil?
Weathering of rock minerals
Precipitation and deposition from the atmosphere
Mineralization of organic matter
Application of mulches and inorganic fertilizers
Which elements are necessary for vine growth that are not considered in soil analysis? Why?
Carbon (C), Hydrogen (H), and Oxygen (O) are supplied atmospherically as Carbon Dioxide and Water.
Chlorine (Cl) is widely available.
What is pH?
A logarithmic scale of the acidity or alkalinity of a solution.
The lower the number, the more acidic the solution is.
What are the ideal pH level and range for viticulture?
Ideal
~7
Optimum Range
5.5 - 8
What is the effect that pH has on viticulture?
pH affects the solubility of nutrients and, thus, their availability to the vine.
What effect does acidic soil have on vine growth?
They are detrimental to vine growth, causing notable nutrient deficiencies such as Nitrogen and Phosphorus.
Soils with pH <5 cause Aluminum and Manganese toxicity.
At pH 4.5, the soil becomes too acidic for vines to perform.
How can soils be made less acidic?
Applying lime or dolomite can increase alkalinity. This should be done before planting vines as it will take time for the minerals to reach the root zone.
What level of soil pH typically occurs in regions where rainfall exceeds 500mm?
Acidic soils are typically associated with such excessive rainfall and may need soil treatments for amelioration.
Rain leeches basic elements such as lime and chalk from the soil in runoff.
Bordeaux is an example.
What level of soil pH typically occurs in regions with less than 500mm of rainfall?
Alkaline soils. There is less runoff due to rain and, thus, more availability of chalk and lime.
What conditions show the most noticeable influence of bedrock?
Temperate regions
Young soils
What is the main determinant of the mineral composition of soil?
The parent material, though parent rock does not necessarily dictate quality of fruit.
What are the three main rock types?
Igneous
Sedimentary
Metamorphic
(heated and/or pressurized sedimentary rock)
What are the viticulturally important bedrocks?
Limestone
Chalk
Slate
Schist
Granite
Volcanic rocks
What is the effect of cultivation on soil pH?
Soils tend to become more acidic due to the release of organic acids on the breakdown of organic material.
What is Limestone? Where is it commonly found?
A sedimentary rock formed mainly of calcium carbonate.
Jerez, Spain
Limestone Coast, Australia
Burgundy, France
St. Emilion, Bordeaux, France
What is Chalk? Where is it commonly found?
A soft, fine-grained, sedimentary type of limestone
Champagne, France
Chablis, France
Portlandian Limestone can be found in
Central Vineyards, Loire Valley, France
Touraine, Loire Valley, France
Southern England, U.K.
What is Kimmeridgian Limestone?
A limestone deposited in the Kimmeridgian period, 157-152 million years ago. Kimmeridgian limestone is rich with fossilized seashells and minerals.
What is Kimmeridgian Soil?
A gray colored soil based on Kimmeridgian limestone. Kimmeridgian Clay is a clay-based soil containing the same limestone. It is soft and water retaining.
The principal soil type of the Loire Valley, Chablis, Champagne, and Burgundy.
What is Portlandian Limestone?
A limestone deposited in the Portlandian period, 120-130 million years ago. It has a higher lime content than Kimmeridgian limestone and is susceptible to fracturing and shattering. It does not contain fossilized seashells characteristic of Kimmeridgian limestone.
What is Portlandian Soil?
A sandy limestone soil found above Portlandian Limestone in Chablis. It lacks the mineral content of and does not retain water as well as Kimmeridgian Soil.
What is Slate? Where is it commonly found?
A metamorphic rock mostly derived from shale usually formed into flat sheets
Mosel, Germany
What is Shale?
A sedimentary rock formed from compacted clay, silt, or sand. It can from Slate when exposed to low-grade pressure or heat.
What is Schist? Where is it commonly found?
A metamorphic rock composed largely of parallel layers. The composition of these layers varies but include Chlorite, Talc, and Graphite.
Douro, Portugal
Cote-Rotie, Northern Rhone, France
What is Granite? Where is it commonly found?
A volcanic rock formed beneath the earth’s surface, giving it a medium to coarse-grained composition
Beaujolais, France
Alsace, France
What are Volcanic Rocks? Where are they commonly found?
Igneous rocks formed at the earth’s surface, giving it a fine grained composition
Etna, Sicily
Madeira, Portugal
Kaiserstuhl, Southern Germany
What depth of a soil profile is most critical and why?
The top meter as it contains the most nutrients and the bulk of the root zone.
What pests can be found in soil?
Phylloxera
Nematodes
What soils are the least preferred habitat of Phylloxera?
Sandy soils
How does Phylloxera affect the vine?
It borrows into the vine’s root system and feeds off of its carbohydrates and water.
What Nematodes are dangerous to grapevines that can be found in soil?
Root-knot Nematodes
Dagger Nematodes
How do Root-knot Nematodes affect the vine? Where are they found?
They cause root damage, impeding water and nutrient uptake. This restricts growth, vigor, and yield.
Found primarily in Australian vineyards.
How do Dagger Nematodes affect the vine? Where are they found?
They are implicated in the spread of diseases such as fanleaf virus
Found in vineyards around the world
What choices are available to combat Nematodes in the vineyard?
Leaving vineyards fallow as the spread of infection by Nematodes is slow. The eggs, however, can survive for a long time so this expensive proposition may not be effective.
Nematocides can control Nematodes, but they kill both harmful and helpful Nematodes and can fail to eradicate the problem.
What effect does high levels of salts in soil have on the vine?
Reduction of grapevine growth and yield
What part of the world has issues with salinity in vineyards?
Australia
What is the correlation between Calcium (Ca) in a soil and its pH?
Direct Correlation.
More Calcium = More Alkalinity
Less Calcium = More Acidity
What is calcareous soil?
Soil with a high lime content
What benefit does calcareous soil offer?
It can restrict Potassium (K) uptake into ripening fruit, maintaining lower juice pH.
Potassium increases pH, making the juice less acidic and, therefore, less desirable.
What risks are associated with calcareous soil?
A lack of available Iron (Fe), Manganese (Mn), and Zinc (Zn)
Lime-induced Chlorosis is a visible symptom of Iron deficiency
What is the role of Calcium in the soil?
It is an important component of soil structure and helps maintain the stability of soil aggregates.
The amount of Calcium in a soil also determines the soil’s pH. Too much creates alkaline soils while too little creates acidic soils
What is Calcite?
A limestone also known as Calcium Carbonate
What is Dolomite?
A limestone that is a mixture of Magnesite (Magnesium Carbonate) and Calcite (Calicium Carbonate)
What is Magnesite?
A limestone also known as Magnesium Carbonate
What is Gypsum?
A fairly soluble calcium mineral that helps keep soil aggregates together. It also prevents them from breaking down into their constituent parts (sand, silt, clay particles) and reduces susceptibility to waterlogging.
What is Marl?
A crumbly mix of clay and limestone
Where does most biological activity in a soil take place?
The upper 10cm
How does drainage work?
Water infiltrates the soil profile and is held temporarily according to the soil’s storage capacity. It is here where the water is available to the vine’s roots.
The water is then drained downward to the water table.
