Fercal

Has the highest tolerance of limestone (CaCO3); it will tolerate up to 50% 'active' limestone (i.e. the limestone part of the soil which the vine can take up; this is very dependent on the composition and structure of the soil). Without a suitable rootstock, excess active limestone has a detrimental effect on growth and causes chlorosis (a physiological ailment, due to various causes, resulting in yellowing of leaves and other green parts of the plant).
Strength of growth is medium, less vigorous than SO4. Tolerant of wet soil, poor resistance to very dry soil, develops a 'creeping' root system (not deep rooted).
It favours fruit-set, encourages early development and maturity. The French claim it produces slightly higher ripeness and lower acidity than SO4.

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