Understanding What You Read About Soils and Fertilization

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Understanding What You Read About Soils and
Fertilization

• Stephen Eng, Evergro Canada
• 630 Garbally Rd. 381-2281
• WIGA Meeting
• April 21,2004

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Oregon Winegrape Growers GuidePublished by
The Oregon WinegrowersAssociation Portland,OR
503-228-8403

• Chapter 3
• Soils and Fertilization

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Basics

• Find out about the soils in your area
• Why are they different?
• What is the significance of the different soils
  and areas?

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Soil pH

• The normal process is for the rain to leach the
  basic elements such as K, Ca, Mg, Na from the
  topsoil.
• Upland native soils are generally slightly to
  strongly acidic in high rainfall areas
• Farming and most fertilizers accelerate
  acidification

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Soil pH Adjustment

• Ideal pH is 6.2
• A pH below 5.2 or gt7.6 would be expected to
  cause reduced growth and yield, and grape quality
  problems.
• Finely ground limestone is generally used to
  reduce acidity ( raise pH ).
• Lime should be spread evenly and mixed into the
  plough layer. This can be done most effectively
  prior to the establishment of the vineyard

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Soil Productivity

• A less productive soil gives the grower a tool
  to control vine growth
• The benefits of growing grapes on productive
  soils should not be overlooked Cultural
  techniques like trellising, hedging, and leaf
  removal may allow the manager to handle excess
  growth on productive soils and still produce
  premium wine.

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Soil Moisture

• AWHC is an important soil feature AWHC is the
  water held in the soil available to the vine.
  Starting in May or June, moisture consumption
  exceeds normal precipitation.
• The amount of soil moisture that is necessary
  or desirable is hard to quantify
• Most vineyards in W. Oregon are purposely grown
  on soils that have limited AWHC to restrict
  growth and produce a specific quality of wine.

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Soil Moisture

• Winegrapes have a remarkable ability to
  function with moisture deficiency, But there is a
  limit
• Severe deficiency limits yield and can reduce
  fruit quality.
• Severe deficiency also limits the vines ability
  to produce a good crop next year.

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Nutrient Testing

• Nutrition, as well as any other input, can be a
  limiting factor for yield or quality
• The effects of a shallow soil, wet soil, soil
  compaction, weed competition, disease and insects
  need to be considered in relation to plant
  nutrition. All these factors can reduce the
  vines ability to utilize or compete for
  nutrients.

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Nutrient testing

• There are systematic ways to analyze a vineyard
  or potential vineyard for nutrient levels
• Soil Testing
• Tissue Testing

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Deficiency Symptoms

• In addition to soil and tissue analysis, visual
  symptoms can be useful in managing vine
  nutrition.
• Nitrogen - acute angle between leaf blade and
  petiole, red petioles,older leaves are light
  green or yellow and vine lack vigour.

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Deficiency Symptoms

• Boron stunted or deformed early shoot growth,
  terminal die-back on shoot tips, poor set, rough
  leaf surface, leaf deformity or interveinal
  chlorosis.
• Potassium light green to yellow leaf margins
  hen marginal leafburn on older leaves, upward or
  downward curl of the leaf margins. Small berries,
  delayed maturity and low sugar.

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Deficiency Symptoms

• Phosphorus small dark green leaves. With
  severe deficiency, red dots appear on the centre
  lobe on basal leaves, and later red dots fill in
  between the veins. Even the smallest veins remain
  green.
• Magnesium early season leaf necrosis or
  reddish-yellow colour between the major veins of
  the leaf in summer or fall.

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Deficiency Symptoms

• Zinc small leaf blades, open sinuses ( leaf
  area near petiole ), asymmetrical leaves, small
  berries from fewer seeds.
• One problem is that deficiencies can occur
  before symptoms appear, and similar symptoms can
  be confusing
• Problems such as wet or compacted soils, root
  diseases and soil insect damage can also look
  like nutrient deficiencies.

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Nutrient Adjustments-Nitrogen

• The most natural source of most nitrogen comes
  from the breakdown of organic matter.
• the grape plant will generally respond to
  nitrogen fertilizer with increased growth. This
  is desirable in establishing a vineyard, but may
  not be desirable in a bearing one.
• A good approach to N fertilization would be to
  fertilize young plants for optimum growth.
  Bearing vines should be fertilized modestly, if
  at all, to achieve the best balance of yield and
  quality.

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Boron

• There is a history of B deficiency problems in
  fruit crops in OR, and winegrapes are having the
  same kinds of problems.
• Cold weather and wet cold soils in the early
  spring can reduce a plants ability to take-up
  and utilize B. Drought the preceding year, and
  late fall or early winter pruning have been
  associated with B problems in winegrapes.
• Boron can be applied to the soil but spray
  applications to the vines are more effective.

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Boron

• Recent research showed a Boron spray after
  harvest that actually wets the bud is the most
  effective way to prevent early spring
  shoot-stunting Boron type deficiencies.
• Delayed pruning until March also improves the B
  level in the developing shoot.
• Pre-bloom B spray may still be an effective way
  to get boron into the flower parts.
• Boron can be toxic, so care should be taken not
  to overdo boron nutrition.

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Boron

• The rate of one pound per acre per year will
  maintain levels without building up excesses.
• The concentration of 2 lb of a 20 soluble B
  per 100 gallons of water is safe and double that
  amount would be safe for a post harvest spray
• Solubor is 20 boron

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Potassium

• Potassium deficiency is aggravated by drought
  and can be confused with symptoms of severe
  drought.
• Potassium fertilizer could raise the pH of the
  grape juice
• Remember The 4 Rs of Fertilization

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• Potassium Chloride can burn.
• Potassium Sulphate is safe to apply at any time
  of year.
• Evergros VI Blend uses potassium sulphate as the
  K source

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Phosphorus

• Phosphorus deficiency in grapes has not been
  identified in Oregon
• P is not available in cold soils.
• P is critical for root development, especially
  for new plantings

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Sulphur

• This element can be deficient if S isnt
  contained in other fertilizers or if S sprays are
  not used for mildew control
• Our soils are deficient in S
• Evergros VI Wine Grape Blend has 11S

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Calcium and Magnesium

• These elements are generally associated with
  adjusting pH
• Dolomite lime contains both Ca and Mg
• pH adjustments are not always done yearly so
  additional Mg fertilizers may be necessary

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Zinc

• Zinc may be deficient in high pH soils or sandy
  soils and high P can accentuate a Zinc
  deficiency
• Evergros VI Wine Grape Blend contains Zn

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VI Wine Grape blend

• 8-17-2011S3Mg0.3B0.3Zn
• A new lower N formula
• 4-18-2412S2.9Mg.25B.25Zn
• ( Strawberry Topdress)

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Nutrient Sprays

• There are situations in which sprays might have
  an advantage over soil applied nutrients.
• Root uptake is the main way to supply these ( N,
  P, K, Mg, Ca ) nutrients.

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Nutrient Sprays

• Commercial nutrient sprays containing multiple
  nutrients are available. Plant Scientists dont
  generally recommend these. The reason is that
  these materials typically dont contain enough of
  a specific element to correct a recognizable
  deficiency and there is no reason to apply a
  nutrient if there isnt a deficiency
• Agree or Disagree?

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PHOSPHORUS NEEDS
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POTASSIUM NEEDS