80 CHARLES ANTHONY GOESSMANN 



of the experiment in 1888, the following facts were 

 clearly in evidence: 



(1) The soil was found to be especially deficient in 

 available potash as a result of the continued close rota- 

 tion of grasses and corn. 



(2) The plats to which potash only was applied re- 

 sponded readily with increased yields. After three 

 years these plats began to show a decided shrinkage in 

 crop-production and more complete fertilizers were 

 needed to maintain the yield. 



(3) Allowing land to be fallow does not materially 

 benefit its productiveness, and should be discour- 

 aged. (Photographs of the yield on the different plats 

 appear in the sixth report of the Station.) The 

 above experiment was considered at the time a very 

 striking illustration of the exhaustion of available 

 soil potash by the continued cropping with grass and 

 corn. 



VIII. Field experiments to compare the influence of an 

 addition of nitrogen in different combinations to the soil 

 under cultivation on the general character of the crop and 

 the annual yield (1889-1892). 



The same field (A) which was used for the previously 

 described experiment was employed in the present 

 case. All of the 11 plats received an equal amount of 

 potash in the form of muriate or double sulphate of 

 potash and magnesia, and of phosphoric acid as dis- 

 solved boneblack. The nitrogen was supplied in the 

 forms of barnyard manure, nitrate of soda, sulphate of 

 ammonia, and dried blood. Three plats did not re- 



