68 CYANAMID — MANUFACTURie, CHEMISTRY AND USES 



"When Prof. Frank requested me six years ago to test 

 Cyanamid as to the conditions under which it could be 

 used as a fertilizer and its relative fertilizing value, I had 

 already been preparing to undertake the test; but I had ex- 

 pected, on the ground of observations made with cyanides and 

 sulphocyanates, a completely negative result from the experi- 

 ments. 



"Our experiments carried out in the laboratory and on small 

 experimental plots have not confirmed my previous assump- 

 tion. Our field experiments have shown that the application 

 of lime nitrogen as a fertilizer was attended with less 

 difficulties than one could directly conclude from the experi- 

 ments carried out in the laboratory and on small experimental 

 plots. Very concentrated solutions of lime nitrogen or ex- 

 ceptionally large applications of this fertilizer act harmfully 

 upon the plants, as is clearly seen from our pot experiments 

 (see page 71 and Fig. 5). Under the normal conditions of 

 agricultural practice, however, a disadvantageous action does 

 not occur, if one follows the directions given for the applica- 

 tion of Cyanamid, and these consist essentially in this that the 

 lime nitrogen must not be applied in excessive quantities and 

 further must not be applied upon acid soils or soils which tend 

 to become acid; that it must be distributed as uniformly as 

 possible upon the surface of the field, and must then be worked 

 into the ground, when it is not used as a top dresser, by deep 

 acting tools, or be plowed under. 



"To illustrate, it should be noted that in our experiments 

 (see page 71) an application of i gram of nitrogen in the form 

 of lime-nitrogen upon 7 kilograms of soil contained in a 

 vessel 20 cm. in diameter did not act harmfully, but acted 

 favorably from the beginning to the end upon the plant growth 

 even when the lime nitrogen was mixed with the soil im- 

 mediately before planting of the seed. Upon a circumference 

 of 20 cm. diameter, however, one does not apply in agricultural 

 practice i gram, but only one-tenth or at the highest two-tenths 

 of a gram of nitrogen. It is therefore clear that one can 



