542 EXPERIMENT STATION RECORD. 



Relative availability and solubility of different nitrogenous fertilizers. 



"In these cases the treatment with au acid solution of potassium permanganate 

 has given the closest approximation to the results of maize cultures." 



A series of pot cultures with oats ami corn to determine the availa- 

 bility of nitrogen in bone of different degrees of fineness are also 

 reported. The pots used were of stout galvanized iron 9.75 in. in 

 diameter and 20 in. long, open at both ends. These were sunk in the 

 soil to within 2 in. of their upper edges. The pots were filled with soil 

 from the station grounds which had not been cultivated for If years or 

 manured for 9 years. The soil of each pot received G.5 gm. acid phos- 

 phate (14.28 per cent of available phosphoric acid), 10 gm. precipitated 

 calcium carbonate, and 5 gm. of a mixture of sulphate of potash, 

 double sulphate of potash and magnesium, and muriate of potash con- 

 taining 47.38 per cent potash. A preliminary crop of oats was grown 

 in the different pots in order to test the uniformity of the soil and to 

 determine the amount of available nitrogen present. 



In the succeeding experiment with corn 5 grades of bone were tested: 

 (1) Bone which passed bolting cloth with holes T ^ in. in diameter and 

 contained 3.38 per cent of nitrogen; (2) that which passed circular 

 holes between 5 ' T| and yio i' 1 - 1]1 diameter and contained 3.90 per cent 

 nitrogen; (3) that which passed circular holes between 2 \- and - b \- in. in 

 diameter and contained 4.07 per cent of nitrogen; (4) that which passed 

 circular holes between -^ and .r- 5 in. in diameter and contained 4.05 per 

 cent nitrogen; (5) that which passed circular holes between 4, and - 1 1 2 - 

 iu. in diameter and contained 4.08 per cent nitrogen. 



Comparative tests were also made of nitrate of soda and cotton-seed 

 meal as sources of nitrogen. The results may be briefly summarized 

 as follows: 



Availability of bom nitrogen. 



Maximum. 



Minimum. 



Grade 1, passed fine bolting cloth 



Grade 2, smaller than ^ in 



Grade 3, B \, to ,,', in 



Grade 4, ^ to JV in 



Grade 5, j' 2 to J in 



Per cent. 

 22, 7 

 7! 5 

 9.2 



5.4 

 7.5 



Per cent. 

 0.0 



_ 2 

 A) 

 .0 

 .0 



"These experiments of a single year have shown that, under the conditions speci- 

 fied, fine bone Hour prepared from the hardest bones (selected raw knuckle bones 



