CYANAMIDE AND NITEATE OF LIME. 275 



Muntz and E. Laine, peat is au excellent means for bringing 

 nitrifying bacteria to very great activity. For this purpose the 

 peat is moistened with a solution of an ammoniacal salt after having 

 mixed it with lime to fix the nitric acid formed. From very de- 

 tailed comparative experiments by P. Wagner, B. Dorsch, S. Mais 

 and M. Popp, ''Land Versucht," 1907 (Vol. LXVI, p. 285), with 

 .cyanamide and various nitrogenous manures, it follows that : — 



1. Sulphate of Ammonia and Nitrate of Ammonia have not shown 

 great differences in their mode of action. 



2. Carbonate of Ammonia produced in loamy soils exactly the 

 same results as sulphate and nitrate of ammonia. In sandy soils 

 it did not act normally on the culture in pots except at a dose of 

 •0"75 grammes applied once ; stronger doses were injurious. 



3. Nitrate of Lime acts normally up to the second dose (1'5 

 grammes) in loamy soil and up to the third dose in sandy soil 

 (2-25 grammes). But from that moment there is an injurious action, 

 •especially in loamy soils. The high percentage of basic nitrate of 

 lime and the still higher percentage of nitrate of lime produce in- 

 jurious effects. 



4. Cyanamide in a dose of 0*75 grm. once applied has given 

 •a favourable result in pots, although a little less than other nitro- 

 genous manures of equal dose. 



5. Fish Guano produced an average useful effect of 78, the 

 action of nitrate of ammonia and of sulphate of ammonia being 

 supposed to equal 100. 



6. Green Manures have produced on sandy ground the same use- 

 ful effect as fish guano in loamy soils ; they were slightly less effective. 



7. Nitrate of Soda, Chili Saltpetre and Sulphate of Ammonia 

 have regularly produced higher yields and a better utilization of the 

 nitrogen than cyanamide. 



The general result of all these agricultural experiments is the 

 following : — 



If the value of nitric nitrogen be expressed by 100, the value 

 of the nitrogen in cyanamide is represented by 90. The lime 

 nitrogen acts a little more feebly when its decomposition in the soil 

 gives rise to the formation of dicyanamide resulting from the action 

 ■of carbonic acid, humic acid, heat and the absence of bacteria. The 

 factors which favour the action of cyanamide are uniform distribu- 

 tion (fifteen days before the time of sowing), perfect mixing of 

 the manure with the soil, sufficient moisture to the soil, a loamy 

 soil rich in bacteria, spreading at the latest on 15th February for 

 ^vinter plants. 



Bules for the use of Cyanamide. — Immendorf has drawn up 

 the following rules for the use of cyanamide : — 



1. Cyanamide does not suit humic acid soils, w^here its action 

 ds uncertain and whei'e it may poison plants. 



