242 Fertilizers 



the second application contains nitrogen drawn from sol- 

 uble sources. The second application is made when the 

 vines are three or four inches high and the fertilizer is 

 dropped right on them and then the entire plant is covered 

 with soil. When this method is practiced, it is believed 

 that more efficient use is made of the nitrogen, and that 

 the vines have ample opportunity for increased root 

 development. While this method is successful in Maine, 

 it has not proved to be superior in New Jersey and warmer 

 climates. It is applicable to both early and late potatoes. 



Form of the constituents. 



In the growing of potatoes, sulfate of potash is generally 

 recommended in preference to the muriate, owing to the 

 supposedly deleterious effect on the quality of the tubers 

 resulting from the large quantities of chlorids contained 

 in the muriate, though the different forms, when properly 

 applied, do not seem to materially influence the yield. 

 That is, if muriate or kainit is applied previous to the 

 planting of potatoes, the deleterious chlorids derived from 

 the muriate may be washed from the soil. There is no 

 doubt that the sulfate improves the appearance of the pota- 

 toes, making them more clean and uniform in size, though 

 experiments that have been conducted do not show a 

 material difference in the chemical composition of the 

 tubers grown with any of the forms. The tendency on 

 the part of the muriate seems to be to diminish the amount 

 of dry matter, and inasmuch as the dry matter is mostly 

 starch, the latter is thereby slightly reduced, though it 

 has not yet been demonstrated that the good quality of 

 the potatoes is measured by the content of starch. 1 



1 Bulletin No. 137, N. Y. State (Geneva) Exp. Sta. ; Bulletin 

 No. 80, N. J. Exp. Sta. 



