CHAPTER VI 

 FERTILIZERS FOR GRAPES 



As regards fertilizers, the grape-grower has much to learn 

 and in learning he must approach the problem with humility 

 of mind. For in his experimenting, which is the best way to 

 learn, he will no sooner arrive at what seems to be a certain 

 conclusion, than another season's results or the yields in an 

 adjoining vineyard will upset the findings of past seasons and 

 those obtained in other places. Unfortunately, there is little 

 real know^ledge to be obtained on the subject, for grape-growers 

 have not yet broken away from time-worn dictums in regard 

 to fertilizers and still follow recommendations drawn from work 

 with truck and field crops. This is excused by the fact that 

 there have been almost no comprehensive experiments in the 

 country with fertilizers for grapes. 



Xo fallacies die harder than the pronouncements of chemists 

 a generation ago that fertilizing consists in putting in the soil 

 approximately that which the plants take out ; and that the 

 chemical composition of the crop affords the necessary guide 

 to fertilizing. These two theories are the basis of nearly every 

 recommendation that can be found for the use of fertilizers in 

 growing crops. The facts applied to the grape,. however, are 

 that the average tillable soil contains a hundred or a thousand 

 times more of the chemical constituents of plants than the 

 grape can possibly take from the soil ; and many experiments 

 in supplying food to plants show that the chemical composi- 

 tion of the plant is not a safe guide to their fertilizer require- 

 H 97 



