1889.] PUBLIC DOCUMENT — Xo. 4. 527 



IV. Experiments with Potatoes. 



The experiments reported in this connection are continua- 

 tions of those described under the same heading in our last 

 annual report. 



One of the experiments has been carried on upon the 

 same portion of jfield "D" since 1884. It was originally 

 instituted for the purpose of studying the effects of high- 

 grade German potash salts, muriate of potash and potash 

 magnesia sulphate, as the main potash source of plant food, 

 on the quantity and the quality of potatoes raised by their 

 assistance. 



The second one, observations with scabby potatoes, owes 

 its origin to the interest created by some observations made 

 in connection with the former ; it was carried on, for impor- 

 tant reasons, upon a different part of the farm. 



A. Observations upon Field ♦' Z>." 



[Variety : Beauty of Hebron.] 



An examination of the preceding records of this experi- 

 ment cannot fail to show that our original plan has been 

 seriously interfered with by an early and persistent appear- 

 ance of either scab or blight, or of both combined. The 

 scab appeared in some parts of the field sooner than in 

 others. — in the fertilized part of the soil sooner or more ex- 

 tensively than in the unfertilized soil. The results in 1884 

 were not as bad as in 1885. The seed potatoes used in 1885 

 were selected from our own crop ; they were planted upon 

 the same part of the field where they had been produced the 

 preceding season. The system of manuring and of general 

 treatment was the same as in the previous year. A blight 

 on the leaves appeared that year in August, and terminated 

 the experiment prematurely. The crop, when harvested 

 August 2Q, was found suffering from scab in all parts of the 

 field engaged in the experiment. 



It was decided, in sight of these tacts, to continue the 

 experiment in 1886 upon the same field, with some modifica- 

 tions, to ascertain, if possible, whether the main influence 

 regarding the results in our past observation had to be 



