122 MANUAL OF MODERN VITICULTURE. 



C. ESTABLISHMENT OF A VINEYARD. 



CHAPTER VII. 

 PREPARATION OF SOIL. 



IST. TRENCHING. 



Soils in which American vines are to be planted must be 

 prepared with great care. From the different facts already 

 mentioned in this book, it results that with regard to 

 adaptation to soil the greatest obstacle is, on the one hand, 

 excessive moisture in winter and the cooling of the soil re- 

 sulting from it. and, on the other hand, considerable loss 

 of water through evaporation in dry summers. The best 

 and the only remedy for both these obstacles is deep 

 and thorough trenching. As a matter of fact, if the excess 

 of water percolates easily through well-divided soil, it also 

 remains longer under these circumstances, for the capillary 

 attraction drawing it towards the surface where it evaporates 

 is less felt than in compact soils. Finally, the roots can 

 penetrate deeper, and find moister surroundings in soils 

 deeply disturbed. 



(A) Depth of trenching. Trenching previous to planting 

 is, therefore, essential, but the depth of this cultural opera- 

 tion naturally varies with the nature of the soil. Soils 

 naturally dry and poor must be disturbed deeper than fresh 

 and fertile soils. In the first case the depth should be 24 

 inches, while in the second 16 or 20 inches might be sufficient. 

 However, if the arable soil is shallow, and rests on permeable 

 limestone subsoil, the latter must not be disturbed, for the 

 roots can naturally penetrate it and get sheltered against 

 drought. 



Trenching must be done much deeper when a new vineyard 

 is planted on the site of an old vineyard immediately after 

 it has been uprooted. This is generally the case with 

 American vines. Under these circumstances a depth oj 30 

 to 32 inches is required. 



