The vine (Vitis vinifera) is a perennial deciduous plant. It is a woody plant with a very long life, including a long juvenile period (3-5 years) during which it cannot produce flowers. They are the most demanding woody plants, due to the need to keep them alive during times of cold or drought. Its economic importance is due to its fruit, the grape, which can be consumed directly or fermented to produce wine. The main nutritional needs of these crops are:

Macronutrients in vine

Nitrogen

This is an essential macro-element in the nutrition of the vine. It promotes budding, setting and flowering. A lack of nitrogen causes the lower leaves to turn yellowish, eventually drying out and displaying browner colours.

Phosphorous

This source of energy is needed to carry out all metabolic processes. Its supply is essential in the flowering and setting stages. It promotes resistance to drought and disease. A lack of phosphorus causes the plant to take on a dark green colour with yellowish leaves that turn brown or black when dry.

Potassium

Its main function is the transport of photosynthesised sugars. It also promotes the absorption of water by the roots and controls the opening and closing of stomata. A lack of potassium causes chlorosis in the leaves, with areas of dead tissue detectable at the edges and between the nerves.

Calcium

This is responsible for synthesising the structural components of the plant. This nutrient is needed throughout all stages of the cycle. Any lack of it may leave the plant vulnerable to fungal attack, due to hormonal imbalance. A lack of calcium may cause distortions in the apex and base of the leaves as a consequence of the death of the end-buds.

Micronutrients in vine

Magnesium

This nutrient is crucial to the effectiveness of photosynthesis, as it forms part of chlorophyll. It is involved in the accumulation and transport of sugars, and also contributes to the ionic balance within the cell. A lack of magnesium may cause the rachis to turn black. The leaves may redden, displaying necrotic areas, and their edges may bend upwards.

Microelements

Manganese

This is a fundamental nutrient for photosynthesis to take place. In addition to promoting the setting and fertility of the buds, it has positive effects on tolerance to diseases caused by fungi. A lack of manganese causes leaves with necrotic areas, and the thinnest veins will remain greenish, resulting in a reticulated appearance.

Iron

This element is crucial for the synthesis of chlorophyll, as is magnesium. It is involved in the respiration and redox processes in the plant. A lack of iron causes young leaves to develop chlorosis, with the main veins turning dark green. The stems will be thin and short.

Boron

This nutrient is fundamental, since it is involved in the synthesis of the cell wall, helps the mobilisation of sugars, and is crucial to setting, promoting the growth of the pollen tube. A lack of boron  may cause incorrect curdling. The leaves of the end-bud twist, ending with the death of the entire stem and end-bud.

Copper

This element, which is involved in the synthesis of lignin, provides stiffness to the tissues and optimises the transport of water, reducing water losses. It defends against pathogens such as fungi and bacteria by inducing synthesis of phytoalexins. A lack of copper causes constant withering of the youngest leaves. When the lack of this element is significant, the branches and stem will not be able to stand upright.

Zinc

This nutrient promotes fruit setting as well as protein synthesis. Zinc induces the synthesis of growth hormones in the plant and ensures proper maturation. It can provide advantages against fungal attacks. A lack of zinc may cause incorrect setting. In addition, a shortening of the stem internodes may be observed, along with ‘zig-zag’ growth patterns.