SUBMERSION OF VINEYARDS. 197 



But this fact is only of secondary importance from a 

 practical point of view, and one should not discard submer- 

 sion if the only reason against it is that water does not con- 

 tain fertilizing matters. 



2ND. SOIL. 



(A.) Permeability. Soils to which submersion is to be 

 applied must not be too permeable. The permeability of 

 the soil is not only an obstacle on account of the large quan- 

 tities of water required and the washing resulting from the 

 current taking place through the soil, but it also fixes in the 

 subsoil a number of small air bubbles on account of the 

 downward movement of the water. These bubbles, as we 

 have seen, enable phylloxera to live. Clayey-calcareous 

 and clayey-siliceous compact subsoils are those which 

 generally realize the best conditions. Those containing 

 pebbles or formed of disintegrated rock have, on the con- 

 trary, often resulted in failure. 



(B.) The contour of .the land. Land to be submerged must 

 be horizontal or only have a slope of 2 to 3 per cent. Greater 

 slopes render necessary the establishment of a large number 

 of banks. This is expensive, and has the disadvantage of 

 diminishing the area of the basins. Further, the surface of 

 the soil must be regular so as to have an even depth of 

 water right through. 



SRD. ADAPTATION OF C^PAGES TO SUBMERSION. 



No cepage to which submersion has been applied so far 

 seems to have suffered directly from its effects, but many 

 have been affected in a more or less acute way by certain 

 accidents to which they were predisposed by nature. 



Clairette and Garignane, for instance, which are sensitive 

 to anthracnosis, are often largely affected by this disease 

 when submerged.* Grenache and Alicante, which ripen 

 their wood late in the season, suffer greatly from the check 

 submersion gives to their vegetation, especially when it is 

 applied rather early in the season. 



Aramon, Mataro, Tinto, Malbeck, Cabernet, Shiraz, and 

 Chasselas may be submerged without detriment. 



*This is probably the result of the special situation of the vineyard rather than 

 of submersion itself. 



