Calcium Cvanamidr. 767 



as condemnatory to the use of canamide, for other fertilizers may act 

 similarly. Large applications of nitrate of soda, for example, retard 

 the maturity of such crops as sugar beet. Cyanamide does the same, 

 and its addition does not result in as large an increase of sug-ar per 

 acre of beet as the addition of nitrate of lime or nitrate of soda. 

 When added immediately hefnre the sowing of the seed cyanamide 

 was found to liasten tlie development of l)eets (E.xp. Sfn. Fee, vol. o4, 

 V. 431). 



Of course cyanamide sliould not be added in too larg-e (jUiintlties. 

 ))ut then over-manuring of ony kind is apt to be harmful. It is con- 

 sidered ad\isable to limit the addition of cyanamide to GO 11). i)er ton 

 of a fertilizer containing half a ton of superphosphate. 



The nltiinate action of cyanamide on vegetatioi] is virtually that 

 of ammonia and nitrates, for in the soil the cyanamide, in process of 

 time, becomes converted first into urea, then into ammonia, and 

 finally into nitrates, and these changes proceed more rapidly in 

 sterilized than in unsterilized soil. 



In mixed fertilizers cyanamide causes reversion of the phosphoric 

 oxide, but no loss of nitrogen is involved. If such a mixture however, 

 is left to stand, its fertilizing value has been found to become less. 

 Again, it must be remarked, other materials cause similar reversion; 

 lime, for example, but lime is not for that reason discarded as a 

 fertilizer 



A decidedly beneficial effect of cyanamide is that it retards 

 (lenitrification of other inorganic nitrogenous fertilizers, and so adds 

 to their durability '"while being itself also a nitrogenous fertilizer." 

 (Ej'p. Stn. Rec, vol 34, p. 220). 



An injurious effect has been noticed on acid meadow soils which 

 are excessively damp (Exp. Stn. Rec, vol 34, p. 820), but this, too, 

 cannot be counted to the discredit of cyanamide. 



C'yanamide has repeatedly been declared to possess a lower 



FKirriLizTNG Value 



than ammonium sulpliate or sodium nitrate as a constituent 

 of a mixed fertilizer, but it has been proved to be of special 

 value in increasing the yield of beets and potatoes, in which respect 

 it has been pronounced {Exp. Stn. Rec, vol. 34, p. 24), practically 

 equal to sodium nitrate, a mixture of cyanamide and sodium nitrate 

 being particularly recommended for all kinds of beet. 



When used alone cyanamide has been recommended as a top- 

 dressing for grains but not for potatoes. In the latter case it gives 

 best results if harrowed in before planting. Hoffmann (Deut. Landw. 

 Presse, 1915, pp. 489, 490) has compared the value of cyanamide as a 

 i op-dressing with that of sodium nitrate and ammonium sulphate as 

 follows, as the result of exjjeriments (Exp. Stn. Rec, vol. 34, p. 622). 



Sodium Ammonium 



Nitrati'. Sulphate. 



For rye 100 75.7 



,, wheat 100 75.7 



,, barley 100 77.1 



' ,, oats 100 132.5 



,, potatoes 100 85.0 



