The spring development of roots

The spring development of roots

In spring, up to the moment of pre-veraison, the roots develop at the same time as the increase in vegetation. This phase takes place with different speeds until the green mass of the row is completed, followed by the progressive arrest of the development of the shoots. The phenomenon is not of equal linearity every year, as it is also conditioned by climatic trends and soil conditions: humidity and temperature.

Before reaching the ripening of the bunches and the setting of the shoots, the large quantity of substances synthesized by the foliage are largely translocated towards the root systems, which complete their spring formation by adapting to the new dimensions of the plant.

The factors of rhizogenesis

The elongation zones of the root systems are the most delicate parts of the entire plant. In fact, they live in the depths of the ground sheltered from the variability of atmospheric agents.
The fundamental factors for their development are water, oxygen and heat. The first two represent limiting factors on the phenomenon, while heat can be more or less favorable to the speed of development.

 Water and air occupy the empty spaces in the ground between the solid parts. These spaces can be of different sizes and quantities, depending on the physical and structural characteristics of the land itself. In relation to these elements, the root systems select themselves, spreading to the layers where they find the most suitable balance. Thus it may happen that in soils with a certain type of texture the roots are more superficial than in others.
The greatest sufferings that the roots may incur in this phase are mostly induced involuntarily by the winegrower with the cultivation operations.

The tillage of the land

The decision to work the land is part of a precise and traditional technique which still maintains its validity today. It is advisable to till the soil considering the physical state of the soil, which must be dry on the surface and with a moderate reserve of humidity in the underlying layers. In any case, it is important to avoid the formation of asphyxiated areas, where the empty spaces are occupied to a greater extent by water and less by oxygen: the growth of the roots would be forcibly hindered in these conditions. In severe cases, it could even lead to the death of the most delicate parts. The functions of assimilation of the nutritive elements could stop and the damages also appear at the level of the hair.

In many vineyards, following these difficulties, the technique of permanent grassing of the soil was adopted.
Another basic element is the phenological and physiological condition of the plants. Theoretically, this aspect may not be relevant, provided that hoeing is carried out perfectly and in ideal soil conditions. Since it is never possible to have such certainty, it becomes important not to change the balance of the soil when the vines interact intensely with it.

Time of intervention

Interpreting and knowing in the summer the moments of greatest sensitivity of the plants towards the processes is difficult. In fact, the temporary vegetative arrest does not imply the slowing down of the plant’s functions. In many cases it can instead indicate the change of the activities carried out, therefore the consequent potential suffering due to the sudden variations of external factors. Among the latter, mechanical surface processing has, as already mentioned, a considerable weight. A confirmation of all this is recurrent in soils rich in limestone, where it can happen that, following a process carried out in this period, the vines turn yellow very quickly, without having complete recovery in the season.

Soil tillage is often an obstacle to the roots and their well-being. Summer hoeing, aimed at conserving underground humidity and interrupting cracks in clayey soils, can be useful but not in all situations.
Suffering induced to the root system could partially alter the phenological cycle of the year with various types of repercussions on the ripening of the bunches and shoots.