Considerations about applying nitrogen fertilizers to our vineyard

When applying nitrogen to a vineyard to correct a deficiency or maintain its level in the vine at adequate levels, it is important to remember that the uncontrolled use of nitrogen has a decisive influence on grape composition and production. When the nitrogen content in plants is high, the composition of the grape is mainly affected by the consequences of increased vegetative growth (e.g. microclimate of the vegetative wall).

 

 

 

 

The increased density of vegetation leads to low light penetration and low temperatures in the fruiting zone, which can be beneficial or destructive depending on the prevailing climatic conditions.

 

 

In addition, changes in the microclimate of plants as a result of limited light penetration and temperature change, primarily, can affect the rate of photosynthesis and thereby the amount of photosynthesis products formed (Kriedemann 1968).

Given the characteristics of any support system, increasing vigorousness implies increased density resulting in differentiation of the microclimate of the vegetative wall (Smart et al. 1985, Wolf and Pool 1988, Bell and Robson 1999).

Increased density results in a decrease in the ratio between unshaded and shaded leaves (Bell 1994). This has the potential to limit the production of photosynthesis products because an increasing number of sheets do not photosynthesize to the maximum possible due to leaf shading (Mullins et al. 1992).

The change in the microclimate of the vegetative wall involves the differentiation of a number of environmental factors within the vegetative wall, such as solar radiation, temperature, wind speed and evaporation (Smart 1985). Light and temperature exert a strong influence on rail metabolism (Iland 1989a,b).

The increased density of vegetation leads to low light penetration and low temperatures in the fruiting zone, which can be beneficial or destructive depending on the prevailing climatic conditions.