1912. 



PUBLIC DOCUMENT — Xo. 31. 



209 



blc the elements contained in the peat. The water used in flood- 

 ing and irrigating mav be regarded in a similar way, since it 

 is as pure as the average public water supply and often purer. 



Analyses of the cranberries and cranberry vines reveal an 

 unusually low proportion of nitrogen and ash constituents, espe- 

 cially in the fruit which, as a rule, is all that is removed from 

 the bog. 



Table I. — Composition of Cranberries and Vines. 



A crop of 100 barrels of cranberries per acre, weighing 10,- 

 000 pounds, will contain only 7 pounds of nitrogen, 3 pounds of 

 phosphoric acid and 8 pounds of potash. One ton of dried vines 

 would contain 15 pounds of nitrogen, 6.2 pounds of i)hosphoric 

 acid and 8 pounds of potash. These figures show clearly that 

 the cranberry crop will never exhaust the potential fertility of 

 the bog ; but it is equally plain that it has become accustomed to 

 a scanty nourishment, and they do not answer the question, 

 " Shall fertilizers be used ? " 



There are oil record only three series of fertilizer tests on 

 the cranberry crop. They are somewhat empirical and throw 

 little light on the problem. 



An experiment in New Jersey was reported in 1895.'"' A 

 com])lete fertilizer gave the best results, with the next best from 

 the nitrogen with phosphorus and nitrogen with potash. This 

 was indicative of the actual need of nitrogen ; but the soil was 

 described as a black sand somewhat too dry for a good bog. 



In Wisconsin Whitson began a series of fertilizer tests in 

 1904,^ the last detailed report of which was published in 1907.^ 



' Mass. State Exp. Sta. Rept., 1889, p. 274; 1893, pp. 330, 370. 



2 N. J. Agr. Exp. Sta. Rept., 1898, pp. 122, 123. 



3 Ann. Rept., N. J. Agr. Exp. Sta., 1895, p. 110. 



* Whitson, A. R., Ann. Rept., Wis. .\gr. Exp. Sta., 1905, pp. 291 and 292. 

 6 Ann. Rept., Wis. Agr. Exp. Sta., 1907, p. 305. 



