162 SOILS AND FERTILIZERS 



merely a trade name. Another name that has been used is 

 lime nitrogen. The latter is good because it emphasizes the 

 fact that the fertilizer contains lime, which is a point in its 

 favor, as the lime helps to overcome soil acidity. There is 

 about 26 percent of caustic lime in the fertilizer. How- 

 ever, in the quantities in which fertilizers are used the 

 sweetening effect of the lime would not go very far. The 

 fertilizer usually contains between 15 and 16 percent of nitro- 

 gen, which puts it on a par with nitrate of soda in this 

 respect. 



211. Changes in the soil. — Cyanamid must be decom- 

 posed in the soil before its nitrogen becomes available to 

 plants. It is, therefore, not as rapid in its effects as is nitrate 

 of soda, but resembles sulfate of ammonia in this respect. 



Under some conditions products may be formed during its 

 decomposition that are more or less injurious to plants. 

 This is said to be true when the fertilizer is incorporated 

 with water saturated soil or very acid soil. As decomposi- 

 tion proceeds these injurious substances are destroyed. In 

 order to be sure that no injury will be done to plants, cyan- 

 amid should be applied at least a week before planting. 



It is not well adapted to use on very sandy soils, nor does 

 it give its best results when used as a top dressing, as it re- 

 quires incorporation with the. soil for its proper decomposi- 

 tion. Ordinarily its fertilizing value is not greatly below that 

 of sodium nitrate, and is about equal to that of sulfate of 

 ammonia. 



212. Fertilizers containing organic nitrogen. — There are 

 a great many materials containing organic nitrogen that 

 are used as fertilizers. As many of them are of little or no 

 value for other purposes they would be wasted if not used to 

 benefit the land. There is very great diversity as to their 

 fertilizer value, but in general the availability of the nitrogen 

 to* plants is less than that of nitrate of soda. In order that 



