ANNUAL REPORT, 1933 9 



It may be noted that a distinct response to nitrogen and potash, but no re- 

 sponse to phosphoric acid, all as top-dressing, is indicated by these figures. 



Forms of Nitrogen. This experiment in the top-dressing of an old mowing 

 was started in 1932. Cyanamid came from last place last year to first place this 

 year in the order of effectiveness. The relative yields from the various treat- 

 ments for 1933 are as follows: 



Check (no nitrogen) 100 



Ammonium Sulfate 192 



Urea 193 



Nitrate of Soda 216 



Cyanamid 220 



This field has received no phosphatic or potassic fertilizers and no lime since 

 the experiment began. 



Experiments with the New£r Nitrogen Fertilizers. (A. B. Beaumont.) In the 

 spring of 1929 a field experiment was started with several of the new nitrogen 

 fertilizers, some of the old standard carriers being used for comparison. The 

 materials used were: 



Per cent Per cent 

 N P.Os 



Ammonium Sulfate (by-product) 20.5 



Ammonium Phosphate (Ammo-Phos) . ... 11 48 



Diammonium Phosphate (Di-ammonphos) 21 53.4 



Ammonium Chloride 26.2 



Calcium Nitrate 15.5 



Nitrate of Soda (Chilean) 15.5 



Nitrate of Soda (synthetic) 16.25 



Urea 46 



Calcium Cyanamid 22 



For the first two years of the experiment, the fertilizer used on all plots was 

 equivalent to 800 pounds of a mixture containing 4 per cent N, 17.45 per cent 

 P.2O5, and 6 per cent K.,0. No fertilizer was applied the third year when hay 

 was grown. The fourth and fifth years the fertilizer was equivalent to 1200 

 pounds of the mixture indicated. The reaction of the soil used was about pH 6.2 

 at the beginning of the experiment. Four crops of ear corn and one crop of 

 mixed grass and clover hay have been grown in the period 1929-1933. No signi- 

 ficant differences in yield have been obtained from the different fertilizers, although 

 the yield from ammonium sulfate is trending low. This material and ammonium 

 chloride have slightly lowered the pH value of the soil. The nitrates and calcium 

 cyanamid, particularly the latter, have somewhat raised the pH value. The 

 two ammonium phosphates and urea have not effected marked differences in 

 the soil reaction. 



This experiment indicates that on a soil of this character one may expect almost 

 identical results from the nitrogen fertilizers used for tilled crops having require- 

 ments similar to those of corn for a period of five years at least, without the use 

 of lime. If the experiment is to be continued on the same plan, further diver- 

 gence in soil conditions resulting from the use of the different nitrogen fertilizers, 

 and corresponding variations in yield of crops may be expected. 



