ioo6 The New Nitrogenous Fertilisers, [march, 



THE NEW NITROGENOUS FERTILISERS- 

 CALCIUM, CYANAMIDE, AND NITRATE OF LIME. 



A. D. Hall, M.A., F.R.S., 



Director of the Rothamsted Experimental Station. 



In view of the importance of the two new fertilisers con- 

 taining nitrogen extracted from the atmosphere— calcium 

 cyanamide or nitrolim and nitrate of lime — both of which are 

 now becoming regular articles of commerce, the results of a 

 comparative trial of these manures against sulphate of 

 ammonia and nitrate of soda, made at Rothamsted in 1909, 

 may not be without interest. The experimental plots were 

 situated in Little Hoos field, the soil of which, as of the other 

 Rothamsted fields, is a heavy clay loam containing between 

 1 and 2 per cent, of carbonate of lime in the surface soil; 

 the land was in poor condition, and had not received dung 

 for many years previously. The land was given a uniform 

 manuring of 336 lb. of superphosphate (37 per cent, soluble) 

 per acre, then each plot, except the two control plots, received 

 50 lb. of nitrogen per acre in one of the selected forms — 

 nitrate of soda, nitrate of lime, sulphate of ammonia, and 

 calcium cyanamide. 



The crop selected for experiment was barley — Archer's stiff 

 straw ; but owing to the cold and wet character of the season, 

 the amount of nitrogen applied was too large, despite the 

 poor condition of the soil, so that the plant on all the plots 

 receiving nitrogen became much laid during July. In con- 

 sequence, the plots had to be cut by the scythe, and the 

 weights of straw are not very trustworthy owing to the diffi- 

 culty of cutting them uniformly. 



The manures were applied on March 8th and ploughed in, 

 but showery weather followed, and it was not possible to sow 

 the barley until April 6th. Germination was even and 

 regular; all through the early part of the season growth was 

 good, and the plots looked uniform ; the plots receiving either 

 nitrate of soda or nitrate of lime always appeared to be a little 

 better and taller, this being usually the case at Rothamsted, 

 where nitrate of soda always produces more straw than do 

 ammonium salts. The following table gives the details of 

 the yield on the ten plots, there being duplicate plots for 

 each manure ; — - 



