Grapes (Wine)
Basic Information
The qualitative potential of the grape can be achieved through moderate levels of vigor and yield. Therefore, the best terroirs are located in less fertile soils, with slopes and good sun orientation.
The optimum management systems are defined by a combination of different parameters. These include the density, which varies according to the climate of the vineyard, the desired yields, the orientation, the method of trellising as well as the type of pruning.
The vine's requirements for nutrients are low, particularly for phosphorus and nitrogen.
To ensure a good quality of the grape the vigor of the vine has to be limited and as a result, a moderate yield has to be accepted.
Detailed Description
Nitrogen is necessary for the growth of the vine, but only in small quantities. An excess of nitrogen can be harmful to the quality of the grape, as nitrogen promotes the production of proteins to the detriment of the phenolic compounds, on which the flavors are based. A nitrogen supply to the soil of about 30 - 50 kg/ha/year, depending on the variety and method of cultivation, can cover the nitrogen demands of the crop. The use of foliar sprays can also be considered.
Phosphorus plays an important role in the vegetative development of the vine. The presence of mycorrhizae and other micro-organisms at the root level allows a good utilization of the soil's phosphorus reserves.
An annual phosphate maintenance supply of around 15 - 20 units/ha should preferably be applied to the soil. Potassium influences the metabolism of the vine, as well as the acidity. The peaks of demand are at bud break and during the maturation phase. The negative effects of potassium deficiency on quality can occur even before we notice any visual symptoms. The sugar content of the grapes is reduced, the acidity remains high and the synthesis of phenolic compounds is limited. For an effective potassium application, it is recommended to apply an average of about 60 - 80 kg/ha/year, depending on the variety and the method of production.
It is suggested to have a balance in the potassium and magnesium applications on the basis of petiolar analysis from the K/Mg ratio. This avoids the competition between these two elements for absorption by the roots. Trace elements play an important physiological role in all plant metabolisms, like photosynthesis, respiration and energy transport. Iron deficiency occurs more often and is linked to the cultivation of vines on calcareous soils, where iron remains bound in the soil due to a high pH and is, therefore, not available for the plants.
The biostimulation (e.g. Basfoliar® Kelp SL) on table grapes begins with the correct fertilization to the soil, with complete fertigation programs with Hakaphos® or NovaTec® Solub. For foliar application Basfoliar® Boro SL and Fetrilon® are recommended.