New York Agricultural Experiment Station. 575 



Further examination of Table I shows that yearly yields are 

 exceedingly variable. A year of large yield is usually followed by 

 short crops for two or three years; these in turn are succeeded by 

 another yield considerably above the average. These variations 

 are attributed to many causes, among which are severe winters, 

 late spring frosts, summer drouths, cold, wet weather during the 

 growing season, insect depredations and lack of fertility. Undoubt- 

 edly any of the causes ascribed could materially affect the yield 

 but it is certain that decreasing yields in all vineyards are not due 

 to the same causes. Furthermore, vineyards that are in a weakened 

 condition because of some obscure trouble are less able to stand 

 low temperatures, drouths, and insect invasions, some one of 

 which are of almost annual occurrence. Again, some vineyards 

 produce very fair annual crops even though subjected to several 

 unfavorable conditions, while others, seemingly under the same 

 influences, are unprofitable. 



AN EFFORT TO STOP THE DECREASE. 



This Bulletin presents part of the results of five years of work 

 by this Station in an effort to find out how the decreasing yields 

 can be checked. Experiments in the control of insect and fungus 

 pests and with commercial fertilizers, stable manure, green manures 

 and lime have been made. The present report is an account of the 

 experiments with commercial fertilizers. 



A VINEYARD SURVEY. 



In order to obtain at first hand the experiences of vineyardists 

 with commercial fertilizers and stable manures, the junior author 

 made a farm-to-farm survey in 1909. Growers of grapes to the 

 number of 482 were interviewed and in most instances their vine- 

 yards were examined. The following statements sum up the infor- 

 mation obtained pertinent to the subject under discussion. 



The use of commercial fertilizers has been and is an extremely 

 irregular practice, irregular not only as to frequency of application, 

 but also as to the carriers and the elements used. Of the 482 growers 

 interviewed, only 46 had used commercial fertilizers in 1904, 49 in 

 in 1905, 102 in 1906, 107 in 1907 and 178 in 1908; or in all 252 used 

 commercial fertilizers one or more years during the five for which 



