106 MANUAL OF AMERICAN GRAPE-GROWING 



in vineyards in which the soil is as uneven as in these, which 

 were in every case selected because there was an appearance 

 of uniformity. A problem before grape-growers is to make 

 uniform all conditions in their vineyards, and the vines must 

 be kept free from pests if fertilizers are to be profitably used. 



Hoiv a grape-grower may know when Jiis vines need fertilizers. 



A grape-grower may assume that his vines do not need fer- 

 tilizers if they are vigorous and making a fair annual growth. 

 When the vineyard is found to be failing in vigor, the first step 

 to be taken is to make sure that the drainage is good ; the second 

 step, to control insect and fungous pests; the third, to give 

 tillage and good care ; and the fourth step is to apply fertilizers 

 if they be found necessary. Few vineyards will be found to 

 require a complete fertilizer. What the special requirements 

 of a vineyard are can be ascertained only by experiment and 

 are probably not ascertainable by analyses of the soil. This 

 experiment furnishes suggestions as to how the grape-grower 

 may test the value of fertilizers in his own vineyard. 



Applying frrtiJlzrrs. 



When it is certain that vines need fertilization, and what is 

 wanted is known, the fertilizers should be put on in the spring 

 and be worked in by the spring cultivation. Stable manure 

 should be plowed under. Grape roots forage throughout the 

 whole top layer of soil so that the land should be covered with 

 the fertilizer, whether chemical or barnyard manure. Applica- 

 tions of commercial fertilizers are generally spread broadcast, 

 though it is better to drill them in if the foliage is out on the 

 vines and thus avoid possible injury to tender foliage. Com- 

 mercial fertilizers should be mixed thoroughly and in a finely 

 divided state. In leachy soils, nitrate of soda ought not to be 

 applied too early in the season, as it will quickly wash down 

 out of reach of the grape roots. 



