234 



EXPERIMENT STATION RECORD. 



castor pomace, steamed horn ami hoof, and lish, and about one-third of that of tank- 

 age. The hone used was very dense and hard, unlike most of the ground hone which 

 is sold in our market as a fertilizer, and presumably less readily available. The 

 subject is further discussed in the following paper. . . . 



"The nitrogen of tankage (which contains considerable bone, 'hone tankage') 

 lias an availability, compared with that of nil rate-nitrogen, of 49 per cent, while the 

 nitrogen of cotton seed, linseed, and castor pomace, as well as that of horn and hoof 

 and in lish, had an availability of from 64 to 69 per cent. 



' The experiments of 1897 show but little difference in the availability of nitrogen 

 in cotton seed, Linseed, castor pomace, horn and hoof, and fish* In this year the 

 nitrogen of blood had a higher availability than that of the materials just named." 



Iii the second series of experiments (with Hungarian grass) "the 

 apparatus and method, kind and amount of soil, method of mixing and 

 filling, watering and care during growth " were the same as in the above 

 experiments. With the soil of each pot were carefully mixed 50 gm. of 

 carefully precipitated calcium carbonate and 5 gm. of potassium phos- 

 phate containing 0.1971 gm. of phosphoric acid and 0.2620 gm. of potash. 

 The nitrogenous materials used were nitrate of soda, cotton-seed meal, 

 and bone in three different grades of fineness ( T £„ in., ^ in., and jk- in.). 

 Detailed data are given in a table. The principal results may be sum- 

 marized as follows : 



Percenta;/? availability of different forms of nitrogen in pot experiments with Hungarian 



grass. 



Nitrogen 

 availa- 

 bility 

 reckoned 



Nitrate of soda. . 

 Cottonseed meal 

 Bone, grade A... 

 Bone, grade B. .. 

 Bone, grade C... 



nitrate. 



Per cent. 



100.0 



57.9 



11.3 



8.5 



5.6 



a Excluded from the average. 



"It thus appears that in these cultures, while 95.3 per cent of the nitrogen of 

 nitrate of soda and 57.9 per cent of that of cotton-seed meal were taken up by the 

 crop, under similar conditions, only 11.3 per cent of the nitrogen of the finest bone 

 flour was taken by the crops and still less than that percentage from coarser grades. 



"These figures do not indicate that the nitrogen of bone is always or generally 

 inferior to that of other animal and vegetable materials. 



"Bone fiuds its most profitable use on crops like grass and clover, which are not 

 annuals, but whose roots occupy the soil through the whole year and are more or 

 less active at all seasons. 



"The best grass lands, too, are loams inclined to be heavy or clayey rather than 

 sandy and, in consequence, retentive of moisture. On such soils it is very likely that 

 hone decomposes more rapidly than in the sandy loam of our experiment and the 

 perennial roots of the crops named would certainly be more efficient in taking up 

 the nitrogen of fertilizers than those of the short-lived plants (oats and Hungarian 

 grass) used in our experiments. It should also he noted that the hone used by us 

 was of the hardest kind, such as is used for the manufacture of ' ivory ' goods, which 

 is presumably more slowly decomposed and dissolved in the soil than other sorts." 



