190').] PUBLIC DOCUMENT — No. 33. 117 



rials is as follows : barnyard manure, nitrate of soda, dried 

 blood, sulfate of ammonia. The nitrate ranks relatively 

 lower this year than in any previous year of the experiment 

 except last. On the basis of increases in all the crops grown 

 since the experiment began, as compared with the no-nitrogen 

 plots, the materials rank as follows : nitrate of soda, 100 ; 

 barnyard maniu'e, 83.0; dried blood, (56.9; sulfate of am- 

 monia, 56.9. In this experiment we are also testing the 

 stubble value to succeeding crops of legumes on the no-nitro- 

 gen plots. The results of this 3^ear indicate the soy bean 

 crop stubble to have been of little value. 



II. — To determine the relative value of muriate, as com- 

 pared with high-grade sulfate of potash, for field crops. The 

 results of this year indicate the sulfate to be considerabl}^ 

 superior to the muriate both for rhubarb and for cabbages. 



III. — To determine the relative value of difl'erent potash 

 salts for field crops. The salts under comparison are high- 

 grade sulfate, low-grade sulfate, kainit, muriate, nitrate, car- 

 bonate and silicate. The crops of this year were cabbages, 

 field corn and ensilao-e corn. The most strikinof results 

 of the comparison are the relatively very low yield of the 

 silicate of potash and the relatively high yields obtained on 

 the nitrate and the carbonate. 



IV. — To determine the relative value of phosphates used 

 in quantities furnishing equal phosphoric acid to each plot. 

 The crop of this year was corn. The most striking result 

 was the very inferior yield produced on the plot where 

 Florida soft phosphate is used. This result, in exact agree- 

 ment with results with different crops in earlier years, in- 

 dicates a very low degree of availability for this phosphate. 



V. — A. Soil test with corn. The crop of this year, the 

 sixteenth during which the experiment has continued, was 

 excellent on all plots to which potash has been annually 

 api)lied. Where muriate of potash alone has been continu- 

 ously used, the yield was at the rate of about 47 bushels 

 per acre. Where nmriate of potash and dissolved bone- 

 black have been continuously used, the yield was at the rate 

 of 53 bushels per acre, which is the best crop produced on 

 any ctmibination of fertilizers, and actually exceeds the yield 



