1 



622 EXPERIMENT STATION RECORD. [Vol.38 



p. 513) are reported dealing with ammonification in Caribou silt loam and 

 Washburn silt loam from Maine, Superior clay from Wisconsin, Scottsburg 

 silt loam from Indiana, and soil from the Arlington Farm, Virginia. Leucine 

 and tyrosine were used as the chemicals to be ammonified and were added to 

 100 gm. of soil in amounts equivalent to 100 mg. of nitrogen. 



It was again confirmed that " the process of ammonification is an autocatalytic 

 chemical reaction and that the increase of ammonia in the process is in accord- 



ance with the formula: Log-; =K(* — U). 



A — X 



" The total amount of nitrogen added to be ammonified does not transform 

 into the nitrogen in the form of ammonia in the process of ammonification. 

 The amount of nitrogen transformed into ammonia nitrogen is greatly influenced 

 by both the soils and chemi-cal compounds used." 



Total nitrogen and carbon in cultivated land and land abandoned to 

 grass and weeds, A, W. Blaib and H. C. McLean [Soil ScL, 4 {1011), No. 4. 

 pp. 283-293, fig. 1 ) . — " It is pointed out that the average nitrogen content of 

 land which was allowed to run wild from 1908 to 1916, and which during that 

 period received annual applications of dried fish amounting to 600 lbs. per acre, 

 was essentially the same in 1916 as in 1913. (No samples were collected previ- 

 ous to 1913.) The carbon content of this same land was increased slightly 

 during the period 1913 to 1916. 



" The average nitrogen content of adjoining cultivated plats, under a 5-yeai 

 rotation, was 0.02 per cent less in 1913, and 0.023 per cent less in 1916, than the 

 nitrogen content of the corresponding plats that were allowed to run wild. 

 The average nitrogen content of the cultivated plats was slightly less in 1916 

 than in 1913.' 



" The average carbon content of the cultivated plats was approximately 0.27 

 per cent less in 1913 and 0.3 per cent less in 1916 than the average carbon 

 content of the corresponding plats allowed to run wild. The average cax'bon 

 content of the cultivated soils was slightly less in 1916 than 1913. 



"The two cultivated plats which received no nitrogen (the check plats) 

 yielded, in the crops from these plats, an average total of 196.13 lbs. of nitrogen 

 for the 9 years. The six nitrogen-treated plats yielded, during the same period, 

 an average total of 329.94 lbs. of nitrogen in the crops from these plats. There 

 was recovered from the six nitrogen-treated plats for the 9-year period an 

 average of 36.36 per cent of the nitrogen that was applied. 



" The percentage of nitrogen and carbon in the cultivated soils is decreasing, 

 even where dried fish is applied at the rate of 600 lbs. per acre annually. The 

 percentage of nitrogen in the soils allowed to run wild, and which have received 

 annual applications of nitrogen, appears to run about constant, but the per- 

 centage of carbon is increasing slightly. Much volunteer white clover is appear- 

 ing on the two plats which receive minerals but no nitrogen." 



Loss of organic matter in clover retvirned to soil, G. E. Boltz and C J. 

 ScHOLLENBEKGER (J/o. Bul. OMo Sta., 2 (1917), No. 12, pp. 397-400).— Ex-peri- 

 ments somewhat similar to those previously noted (E. S. R., 36, p. 324) were 

 made to determine the loss of organic matter and nitrogen in a crop of clover 

 subjected to different methods of farm practice. A quantity of dried and finely 

 cut clover amounting to 4 tons per acre was thoroughly mixed with the surface 

 6 in. of soil of duplicate plats, and the same amount of uncut clover spread upon 

 the surface of each of two other plats after spading, all plats being covered 

 with a wire screen immediately after treatment. The experiment extended 

 over a period of 187 days, and samples of soil, clover, and clover residues were 

 analyzed at the beginning and at the end of the period. 



