24 EXPERIMENT STATION RECORD. 



<;eolo(;ic!il oriniii of the soils of this locality, their cLoiuical and physical character, 

 and the fertilizers needed. 



Concerning nitrification, G. Tolo:mki (Staz. Sper. Ar/r. IlaL, 26 (1894), No. 3, j)}). 

 24G-2G3). — A review of the suhject and a record of the author's experiments and 

 oltservations on the conditions under which nitrification occurs. 



On the utilization of marshes, U. Sverdkup (T((/«Av. norske Landhr., 1 (1894), i)p. 

 l.'>5-170). 



The valuation of arable soils on a scientific statistical basis, G. TiiOMS (Jour. 

 Landw., 42(1894), A'o. l,pp. 1-31, fig. 1, d(jm. i).— This is substantially a reprint of 

 an article published in MiU. kaiserl. livldnd. gemelniitz okon. Sac, 1893, No. IS, and 

 already abstracted (E. S. R., 5, p. 418). 



FERTILIZERS. 



Leather refuse, its value in agriculture, J. B. Ltndsey {Agricul- 

 tural tScience, 8 (ISOJ), Ko. 2, pp. 49-61; No. 3, pp. 98-108).— The author 

 reviews methods which have been employed to render the nitrogen of 

 leather available to growing- plants ; pot, plat, and field experiments with 

 leather waste as a fertilizer for different crops; and work on artificial 

 digestion and nitrification of leather. He then reports the results of 

 experiments by himself on the method (proposed by Dabney) of detecting 

 leather in fertilizers by means of a phosphoric acid solution of phosphate 

 of iron; on the digestibility in pepsin and pancreas solutions of raw 

 leather and leather which had been heated with water in a pressure 

 bottle at 110° C. for hours, as compared with that of tankage and dried 

 blood; and in treating leather with different amounts and strengths of 

 sulphuric acid and drying with bone ash or floats, tests being made in 

 the resulting product for tannic acid. 



"The results of the combined experiments in the field and in pots, together with 

 artificial digestion experiments and nitrification experiments, indicate that leather, 

 either raw, roasted, or steamed, is a very slow acting form of nitrogen as a source of 

 plant food. . . . Carefully conducted experiments by Wagner give it a relative 

 value of 20, nitrate of soda being equal to 100. From the mass of evidence at our 

 command it would seem that this figure about expresses its relative worth as a direct 

 source of plant food. ... 



"Artificial digestion experiments show that the nitrogen in either untreated, 

 steamed, or ro.'isted leather after being acted upon by sulphuric acid has a digesti- 

 bility of 70 per cent. If pot and field experiments corroborate the digestion experi- 

 ments, it would make plain that the nitrogen in leather after being thus treated 

 Avonld l)e as available :is a source of plant food as the nitrogen in the average fish, 

 blood, etc. 



" Wliether it would be practicable from au economical standpoint to thus utilize 

 the leather waste is of course another question which must be answered by practical 

 experiments. . . . 



"The various experiuients made would indicate that leather, sulphuric acid, water, 

 and floats should be mixed in about the following relative proportions: 

 2,000 lbs. 50" B. sulphuric acid. 

 GOO lbs. ground leather. 

 800 lbs. water. 

 2.700 lbs. floats. 



