38 EXPERIMENT STATION. [Jan. 



yield on the no-potasli plots was no doubt in considerable 

 measure due to the relatively early death of the foliage. 



NTo explanation can be offered at this time for the ob- 

 served phenomena. Earlier observers, among them Dr. 

 Goessmann and Professor Ma^^nard, have held that a liberal 

 supply of potash has in some cases exercised a marked influ- 

 ence in enabling the foliage of fruits to resist fungous dis- 

 eases. Some European investigators have attributed a sim- 

 ilar effect to potash in connection with potato diseases. This 

 matter should evidently receive further and most careful 

 study, for, if potato blight can be in a measure controlled 

 through more liberal use of potash salts, this will afford a 

 comparatively easy method of reducing the amount of injury 

 due to the fungi attacking the foliage of this important crop. 



IV. — N^ORTH CoEN Acre. — Special Fertilizer v. Fer- 

 tilizer RICHER IN Potash. 



This experiment was begun in 1891. It occupies an acre 

 of ground, divided into four equal plots. Plots 3 and 4 

 were sown to millet during the first two years of the experi- 

 ment, but Avith this exception their treatment has been the 

 same as that of plots 1 and 2, 3 being a duplicate of 1, and 

 4 a duplicate of 2, both as regards fertilizer application and 

 crops produced. During the period under consideration the 

 entire area with the exception noted for plots 3 and 4, has been 

 in corn, with the exception of three two-year periods, 1897 

 and 1898, 1899 and 1900, and the past two years, during 

 which periods the land has been in mixed grass and clover. 

 The method of seeding in every instance has been by sowing 

 in the corn of the year preceding the first of each of the 

 three two-year periods during which hay has been the crop. 



The object in this exj^eriment is to test the question whether 

 the special corn fertilizers offered in our markets are of such 

 composition as seems to be best suited for the production 

 of corn and mixed hay in rotation. Plots 1 and 3 have yearly 

 received an application of fertilizers (a home mixture) fur- 

 nishing per acre the same amount of nitrogen, phosphoric 

 acid and potash as w^ould be furnished by 1,800 pounds of 

 fertilizer having the composition of the average of the spe- 



