Chapter 16

Vineyard Nutrient Management

Essential Plant Nutrients

When any essential element is in short supply, vine function is restricted. A severe shortage of an element typically produces a characteristic deficiency symptom exhibited by the leaves, which usually persists until the deficiency is corrected. Shoots, canes, and fruits may also exhibit characteristic symptoms. Sometimes two or three elements are deficient in varying degrees, resulting in confusing visual symptoms. Conversely, excessive amounts of some elements may be present in the soil and may prevent the vine from functioning properly. Visual symptoms and leaf and soil analysis are all useful to evaluate nutritional status.

Factors Impacting Plant-Nutrient Availability

Nutrient availability can be impacted by soil chemical and physical properties, including parent material and naturally occurring minerals; amount of organic matter; depth to bedrock, sand, or gravel; and permeability, water holding capacity, and drainage. In addition, environmental conditions and crop characteristics have an important impact on nutrient availability. It is not unusual for grapevines in the vineyard or portions of the vineyard to show nutrient deficiencies during periods of the growing season, even where an adequate nutrient management plan is followed. The fact that nutrients are applied does not necessarily mean they are available. Plants obtain most of their nutrients and water from the soil through their root system.

Climate Change and What it Means to for Grapevine Nutrition

Evidence suggests that climatic conditions are changing and will continue to do so, resulting in higher average temperatures and rates of evaporation, reduced rainfall and runoff with greater seasonal variability, and more frequent extreme weather events. With respect to grapevine nutrition, changes in temperature and evaporation are likely to affect the availability of soil water to the vines as well as the internal mechanisms of water movement through the vine.

Fertilizer Antagonisms

For optimum growth, it is not enough to simply have an abundance of available nutrients. Grapevine nutrients also need to be made available in the correct ratios to one another. This is because certain elemental fertilizer ions compete with others for uptake. Such a thing occurs with plant nutrients, in the soil or at the root zone. Many chemical reactions occur at the root zone; some are for the benefit of the plants, while some may be detrimental to plant nutrition.

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