4 How TO MAKE GRAPE CULTURE PROFITABLE IN CALIFORNIA 



their own, California, Riparia or Rupestris roots are twelve or 

 more years old, but where at present no disease exists, by causing 

 the greatest possible difference through cultivation and irrigation 

 methods between moisture contents of soil during May and June, 

 so that the vine throws out immense foliage and sets a heavy crop, 

 and moisture contents of soil during July and August, within three 

 years from commencement'of treatment. This would be easy work 

 indeed, but I may be able to do the same thing with a five-year-old 

 vineyard, at least in some localities. 



The greater the difference in the moisture contents of a soil be 

 tween spring and fall, the greater the liability of the vines to at- 

 tack, not considering the slight resistance which some varieties of 

 Vinifera possess. Such is generally the case in all rich clayey or 

 loamy soils, as these have the greatest capacity for holding mois- 

 ture and at the same time offer the greatest facility for the complete 

 escape of moisture through capillary attraction. The vine on such 

 soils causes its own destruction by evaporating and depleting the 

 soil moisture through its excessive foliage and crop. Like a good 

 many, I have been under the impression that on rich ground the 

 moisture supply never gave out. Digging down once during August 

 and September in places where I knew the ground was heavil} 

 charged with moisture during spring and had been carefully culti- 

 vated and the vines made immense growth, I found the ground 

 just as dry or drier than in the poorer places, where the growth was 

 much smaller. The change from wet to dry was much greater on 

 the rich than on the poor ground and therefore the vines suc- 

 cumbed more quickly. 



Different from countries with summer rains, a distinct differ- 

 ence must be made in California in regard to soils between the. 

 terms "rich" and "moist," and "poor" and "dry." A rich soil is gen- 

 erally wet or moist in the spring and by careful cultivation remains 

 moist if there is not much growing on it, but if any vines or 

 trees with large top-growth are drawing from its mois- 

 ture supply, it may become exceedingly dry. A poor soil 

 is not necessarily dry during the latter part of the sum 

 mer, unless it is shallow or clayey at the same time. 

 If it is loose, deep an4 mixed with gravel and small rocks, 

 which form an impediment to the rising of the moisture to the sur- 

 face, it generally remains much moister than richer soils. As vines 

 do not grow so exuberantly on such soils, the moisture supply is 

 not depleted. Very deep, coarse soils in valleys may become dry, 

 as the moisture sinks away out of reach of the roots and what is 

 left near the surface, is soon exhausted by the vines. 



The trouble, of course, is greatly augmented by excessive bear- 

 ing of a vine and by irregular moisture contents of a soil from year 

 to year, very dry seasons following wet ones and vice versa. It is 

 simply a collapse, paralysis of the vital energy of the vine, brought 

 about as mentioned. It is not an infectious disease ; no vine will 

 take it from another. If the trouble was of such a nature, there would 

 not be any vines left, even in northern California, at this time, as the 

 disease has been found and identified already sixteen years ago in 



