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PHYSIOLOGICAL BALANCE

COMPOSITION OF THE PLANT

C  carbon
H  hydrogen
O  oxygen
lignin, cellulose, sugars (glucoses)
organic acids
92 %
N  nitrogen
P  phosphorus
K  potash
Mg  magnesium
S  sulphur
Ca  calcium

More than 90% of nutrients come from the atmosphere via photosynthesis,

So it is important :

- To encourage photosynthesis by ensuring a maximum penetration of light to the plant :
       = planting at sufficient distance
       = open-centre pruning

- Balanced feeding (depending on the age of the tree and its development)

 
7,4 %
0,6 %
trace elements

EVOLUTION OF THE C/N (Carbon/Nitrogen) RATIO OVER A TREE'S LIFE SPAN

Young tree

It needs a lot of nitrogen, that is a low C/N ratio (about 5). The root system is very active.
The synthesized carbonaceous material serves the development of the plant, as much for the roots as for the leafing system.
Wide, crinkled, dark green leaves, with elongated internodes.
Large proportion of suckers.
Very little, or no fruiting.
Light (formative) pruning or no pruning.
Adult tree

The C/N ratio is about 15 to 20
This ratio favours fruiting. Vegetative buds evolve into fruit buds.
Fairly vigorous growth with medium internodes.
Abundant, regular fruiting.
Maintain this balance for as long as possible.
Normal pruning (formative, regular, thinning out).
Older tree

The C/N ratio is high (about 100).

There is considerable leafing but the root system creates a lot of suberose (cork) cells and becomes less efficient : nitrogen and mineral deficiency.
There is abundant blossom but the flowers die or fall because of the nitrogen deficiency.
Pale, narrow leaves with dry ends, chlorosis.

This can be corrected by suitable fertilization with nitrogen. More severe pruning.
Bibliography : Memento sur la taille des arbres fruitiers à pépins, by Georges BAL.
Chambre d'agriculture de Haute Savoie
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