Natural Wine - Nutrients Necessary for Quality Grape Production
Providing nutrients is critical to maintain a healthy, productive, and sustainable vine which directly correlates to quality grape production. Supplying certain nutrients in appropriate levels encourages photosynthesis, and in turn healthy growth. These nutrients can be organized into Macronutrients and Micronutrients. Macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K) as primary, and Sulfur (S), Magnesium (MG), and Calcium (Ca) as secondary derived from fertilizers. Micronutrients are also sourced from fertilizers and are Zinc (Zn), Boron (B), Iron (Fe), Manganese (Mn), Copper (Cu), Molybdenum (Mo), Nickel (Ni), and Chlorine (Cl). The vine also requires oxygen (O), Carbon (C), and Hydrogen (H) from water and air. Each of these nutrients plays a vital role in supplying the vine with all the tools necessary to produce quality grapes during the entire cycle of the vine.
Nitrogen is the primary macronutrient and the most necessary to the vine, especially for early season growth as it is a major constituent of chlorophyll. It acts as an active part of growth for shoots, leaves, and clusters and is required for photosynthesis and ripe fruit. It is also necessary after harvest for building reserves in the vine, especially in the roots, to be used in the next growth cycle and dormancy. Nitrogen added to soils with low organic matter can increase vigour, this is done in the San Joaquin valley at Raisin vineyard which suffers from nitrogen deficiency derived from warmth and irrigation.
Potassium (K) is the most important metal element and is required for grape cluster growth and concentration as it regulates water movement in the plant. It also contributes to the maturation of canes after harvest. It promotes root growth, which in turn leads to the vines' ability to absorb water and other necessary nutrients. Varieties such as Cabernet Sauvignon and Syrah have high K demand and should not be grafted on K deficient rootstocks such as 420A or 110r unless the soil is high in K. Trials at Ridge in California have utilized these rootstocks in different aspects and blocks depending on the natural levels of potassium to avoid having to fertilize.
Phosphorus (P) is important for transport of energy through the plant, especially in leaves and clusters. It contributes to root development and membrane function which encourage photosynthesis and ripening. It also contributes to the reproductive function of the vine as well as the movement of sugars and carbohydrate storage. P is removed from the vineyard at a rate of 0.6 kg/ton of grapes and by erosion of topsoil. The use of water soluble P fertilizer at Paracombe in Adelaide, AUS is common practice as it releases P quickly back into the soil.
Sulfur acts as a fungicide as well as development of chloroplasts which conduct photosynthesis. This assists in leave and shoot development, fruit development, and ripeness. AlexEli Vineyard in the Willamette Valley blends sulfur with sea kelp which is sprayed throughout the vineyard in winter to promote overall growth and healthy bud development.
Calcium is relevant in organs (shoots, leaves, roots), especially leaves and is a constituent in cell membrane permeability. It is also important for survival during cold winter (dormant period) It is directly related to the strength of berry skins which can increase resistance to disease, mold, and frost. Foliar and soil treatments of calcium are common in Chile.
Magnesium is essential for photosynthesis, part of chlorophyll, therefore very important in leaves in the production of sugar which contributes to ripeness.
Micronutrients, such as Iron, synthesize the chlorophyll in the leaves, therefore are very important to photosynthesis. Boron and Zinc are important for cell division, especially at fruit set as deficiencies cause poor fruit set
Carbon forms the backbone of most plant biomolecules, including proteins, starches and cellulose. Carbon is fixed through photosynthesis; this converts carbon dioxide from the air into carbohydrates which are used to store and transport energy within the plant.
Hydrogen also is necessary for building sugars and building the plant. It is obtained almost entirely from water. Hydrogen ions are imperative for a proton gradient to help drive the electron transport chain in photosynthesis and for respiration
Oxygen is a component of many organic and inorganic molecules within the plant, and is acquired in many forms, mainly from the air via leaves and the soil water via roots.
Macronutrients, and some micronutrients, are necessary to quality grape production by encouraging and sustaining a healthy and productive environment. These essential nutrients can be found in soil and the use of fertilizers can reduce or eliminate deficiencies in the vine and encourage quality grape production.