SOME CONDITIONS AFFECTING THE VALUE OF 

 CALCIUM CYANAMIDE AS A MANURE. 



By T. DUNCAN MOSSCROP, B.Sc. (Agiic), Lond., C.D.A., Wye. 



[The following is an account of experiments carried out by the 

 author during the years 1913-14 in collaboration with Professor S. J. M. 

 Auld, D.Sc, Ph.D., F.I.C. , etc., of University College, Reading. Dr Auld 

 is now engaged in mihtary duties and the task of presenting this report 

 therefore devolves upon the author who wishes it to be clearly under- 

 stood that Professor Auld must not be held responsible for any in- 

 accuracies or other faults.] 



Although calcium cyanamide has now definitely estabhshed itself as 

 one of the nitrogenous manures no clear attempt appears to have been 

 made to ascertain the cause of the injurious effect which it is generally 

 recognised as having upon vegetation and germinating seeds. Hall^ 

 merely states that "the chief drawback to the practical employment of 

 calcium cyanamide as a manure is its light, blow-away character, and 

 the injurious effect upon germinating seeds of the ammonia and other 

 gases given off when it is first apphed to the soil." The first drawback 

 has now been overcome by the introduction of granular calcium 

 cyanamide. With the idea of settling definitely the cause and extent 

 of injury to germinating seeds the following experiments were under- 

 taken. 



The calcium cyanamide used was of the "blow-away" description 

 and was bought in the ordinary way from a manure merchant. 



Bell-jar Experiments. 



Twenty-five cos lettuce seeds w^ere placed on a porous tile under each 

 of four bell- jars which were sealed from the outer air by water. One was 

 used as a control and had no calcium cyanamide. Each of the others had 



^ Fertilisers and Manures, 1909 ed. p. 40. 



