Even if it is often colloquially formulated in this way: It's not the wine that gets fertilized, but the vines in the vineyard. Like all plants, the vine needs nutrients to grow. Since vineyards are large monocultures, these nutrients must be supplied at least partially from outside; this is the purpose of fertilization. Apart from the consumption of nutrients by the vines themselves, the soil is also washed out by precipitation and erosion.
Soil health is essential for the production of high quality wine. Biodiversity and organic farming are important factors that promote the health and humus content of the vineyard soil.
The legal basis for fertilisation in Germany is provided by the Fertilisation Act, the Fertilisation Ordinance and the Fertiliser Ordinance. In addition, the provisions of wine law and plant protection law apply.
The amount of fertiliser and the timing of fertilisation depends on the nutrient content of the soil. By means of soil analyses, the winegrower determines whether and in what form the vineyard soil has a nutrient deficiency. This determines when and how much fertilizer is applied. The amount of fertiliser used essentially depends on whether the winegrower works in a conventional, integrated or ecological way.
One of the most important nutrients for the vine is nitrogen. This element is essential for plant growth and is also involved in the formation of chlorophyll for photosynthesis. Furthermore, the vine needs minerals such as phosphorus, potassium, magnesium, calcium and others.
Fertilization can be done with organic or inorganic (mineral) substances; organic fertilizers are, for example, manure, slurry, compost, mulch, grapevine and pomace; inorganic fertilizers are mineral salts.