70 THE GRAPES OF NEW YORK. 



total rainfall for the 3'ear be taken into consideration but its distribution 

 throughout the seasons must be considered. The grape does best with 

 comparatively little rainfall. When the rainfall is the least possible amount 

 for a good growth of vine the grape crop will be the largest, of best quality 

 and most free from fungi. Wet seasons, and especially wetness during 

 the months of maturing, are disastrous to both quantity and quality of 

 grapes. Thus, in New York it is not possible, with most varieties, to produce 

 good grapes if the average is above six inches each for the three growing 

 months and five inches each for the maturing months. It is far better for 

 the crop that it be as low as four inches for the first named period and two 

 inches for the second period. 



Superfluous moisture in the soil favors too great a growth of vine, checks 

 and weakens the root system, prevents proper setting of fruit, and favors 

 fungi, but hinders the multiplication of phylloxera. In particular, a com- 

 paratively dry soil is desirable for grapes because of its influence on the 

 development of the root system. In dry soils large root systems are devel- 

 oped in the search for the water that the plant must have. When intense 

 droughts occur plants that have stood in damp soils have not sufficient 

 roots to supply the necessary water to the aerial parts and the vines suffer 

 in consequence. Some species and varieties are better fitted for withstand- 

 ing an excess of moisture than others. 



The soil exercises a great influence in determining the suitability of 

 a region for viticulture. Several factors act as soil determinants: (i) Fer- 

 tility; (2) physical characters; (3) soil heat. It is necessary to study each 

 species, and even their varieties, to discover their powers of adaptation to 

 different soils and it is possible to indicate here the good and bad qualities 

 of soils only in the most general way. In the discussion of species and 

 varieties the soil preferences of the different botanical and horticultural 

 groups will be stated more fully. 



Great fertility, as a natural characteristic, is not necessarv in grape 

 regions. Fertilizers, and especially the use of stable manures and cover 

 crops, can be made to supply very largely a lack of fertility. Soils nat- 

 urally too rich produce an overdevelopment of vine. Some species, as 

 Vitis rupcstris, grow naturally in very poor soils, the habitat of the latter 

 being dry ravines and stony places having comparativelv little organic 



