THE EXPERIMENT STATION 83 



obtained from the United States Department of Agri- 

 culture, of several varieties of mangolds, sugar beets, 

 turnips, and carrots. They were grown upon the Sta- 

 tion grounds, observations recorded of the methods of 

 cultivation, photographs taken and published of the 

 more promising varieties, and detailed chemical analy- 

 ses were made and published. 



XI. Experiments to study the economy of using differ- 

 ent commercial sources of phosphoric acid for manurial 

 purposes in farm practice (1890-1 897). * 



The soil had been in grass for a long time, and its 

 supply of available plant-food had become greatly 

 reduced. During 1887-1888-1889 it was planted with 

 crops to still further exhaust the phosphoric acid. The 

 field was divided into five plats, a definite amount of 

 the same form of nitrogen and potash added, and five 

 different sources of phosphoric acid applied on the 

 basis of their market value, namely, 127 pounds of 

 basic slag, 128 pounds of Mona guano, 304 pounds of 

 apatite, 2 131 pounds of South Carolina phosphate, and 

 78 pounds of dissolved boneblack. On the basis of one 

 acre, such applications were at the rate of 850 pounds 

 for slag, Mona guano, and South Carolina phosphate, 

 2000 pounds of apatite, and 500 pounds of boneblack. 

 In 1894 and thereafter the phosphoric acid application 



1 Goessmann discontinued this work with the season of 1896, and it was 

 brought to a conclusion in 1901 by Brooks. 



1 In 1891, apatite could not be secured, hence phosphoric acid was not 

 applied to this plat. In 1892, 129 pounds of Florida hard phosphate were 

 substituted equal to 850 pounds per acre. It could not be considered 

 fair to this phosphate to compare it with others which had been applied 

 two years longer. 



