20 BULLETIN &74, U. S. DEPARTMENT OF AGEICULTUEE. 



stocky growth and lay down many more fruit buds for the succeeding 

 year. 



On an area at Whitesbog in which the proportion of peat to sand 

 was too small to bring about the most vigorous growth of the bushes, 

 an experiment was made in the application, at the rate of 600 pounds 

 per acre, or one-eighth of a pound per square yard, of a special fer- 

 tilizer which is in successful use in cranberry culture as the result 

 of a series of experiments by the New Jersey State Agricultural Ex- 

 periment Station. Important characteristics of this fertilizer are 

 its acidity and its comparative freedom from residues of sulphur. 

 The blueberry bushes to which this fertilizer was applied made con- 

 spicuously better growth than those that were not fertilized, but 

 they neither grew better nor fruited better than bushes mulched 

 with 1 to 2 inches of rotted peat. 



In 1919 and 1920 Mr. Charles S. Beclrwith, of the New Jersey 

 Agricultural Experiment Station, conducted a series of fertilizer 

 experiments with blueberries at T\'liitesbog. The most successful 

 results were obtained with a fertilizer applied in the spring of 1919, 

 made up as follows : 



Pounds. 



Nitrate of soda 170 



Dried blood 230 



Steamed bone 340 



Ptiosphate roclf 340 



Potash 170 



The yield in 1920 from bushes thus fertilized was more than three 

 times as great as from unfertilized bushes in the same very sandy 

 soil. On the basis of this experiment Mr. Beckwith has recommended 

 the application of this fertilizer at the rate of 600 pounds per acre, 

 or an eighth of a pound per square yarcl.'^ 



As a result of these preliminary fertilizer experiments and in view 

 of the fact that the swamp blueberry fruits abundantly and con- 

 tinuously in soils containing the proper proportion and quality of 

 peat and sand, the use of manure or any chemical fertilizer in such 

 plantations is not at present advocated. But if the proportion of 

 peat to sand is so low that the bushes appear to be suffering for 

 nourisliment a mulch of rotted surface peat or half-rotted oak leaves 

 should be applied, or a chemical fertilizer similar in character to 

 the one described above, or some organic nitrogenous substance, such 

 as soy-bean meal or cottonseed meal. 



The swamp blueberry does not require a j^early pruning. When 

 one of the stems of a bush becomes unproductive from injury or old 

 age it should, of course, be cut out. If a large part of a bush needs 

 removal it is better to cut all the stems to the ground and let the 



^ For the details of this experiment, see " The Effect of Fertilizers on Blueberries," 

 published in Soil Science, v. 10, pp. 309 to 312, with plate, October, 1920. 



