A TEST OF COMMERCIAL FERTILIZERS FOR 



GRAPES.* 



U. P. HEDRICK and F. E. GLADWIN. 



SUMMARY. 



i. There has been a decline in yields of grapes in the Chautauqua 

 Grape Belt, the chief grape-growing region of New York. This 

 bulletin is a report of several experiments to determine the value 

 of commercial fertilizers in increasing or restoring former yields. 



2. The experiments under discussion were carried on in a leased 

 vineyard near Fredonia, New York, and in six vineyards in various 

 parts of Chautauqua County in v/hich cooperative work was carried 

 on with the owners. The vineyards were selected to obtain fair 

 averages of soils and of health and vigor of the grape plantations 

 of this region. 



3. The treatments consisted of annual applications of nitrogen 

 at the rate of from 56 to 72 pounds per acre; phosphorus from 18.3 

 pounds to 25.3 pounds per acre; potassium from 52.7 pounds to 

 59.3 pounds per acre; and lime at the rate of 2000 pounds per acre. 

 The nitrogen was applied in nitrate of soda, dried blood and cotton- 

 seed meal, the phosphorus in acid phosphate and the potassium in 

 sulphate of potash. 



4. The results of the experiments are gauged by yield of fruit, 

 effects on the fruit, effects on the foliage and effects on the wood. 

 A brief summary of the results in the Fredonia vineyard is : 



Nitrogenous fertilizers had a marked beneficial effect upon the 

 yield and quality of fruit and upon leaf and wood growth, making 

 it certain that nitrogen is the limiting factor in this vineyard. 



Lime had no appreciable effect in this vineyard and phosphorus 

 and potassium had so small a beneficial effect that their use was 

 not profitable. 



5. In the cooperative experiments not only commercial fer- 

 tilizers but stable manure and green manure crops were used. The 

 results from the use of all are confusing and unsatisfactory, varying 

 greatly in any one vineyard or in the several vineyards compared 

 with one another. 



Reprint of Bulletin No. 381, March; for Popular Edition see p. 920. 



[572] 



