1907.] PUBLIC DOCUMENT — No. 33. 37 



salt and tlie average yield proJuecd by the low-grade and 

 high-grade sulfate and the nitrate are small. Carbonate 

 ranks next, followed by kainit and silicate. The past season 

 (Jnne 1 to August 15) was characterized by rainfall con- 

 siderably below the average. Previous exjDeriments have 

 shown that in such seasons muriate of potash can usually be 

 dej)ended upon to give crops equal to those produced where 

 the sulfates are used. Lime, moreover, is known to offset 

 in a measure the unfavorable results consequent upon con- 

 tinued use of muriate; and the entire field, as stated, was 

 limed this season. 



We are unable at this time to make a report in relation 

 to the quality of the tubers produced on the different fertiliz- 

 ers, but the different lots have been carefully sampled, and 

 such a report will be made later. 



The Effect of the Liming. — Attention is called to the fact 

 that in using lime immediately preceding the potato crop we 

 departed from the usually accepted rule. Such use of lime 

 is not regarded as desirable on account of the chances that 

 the immediately following crop of potatoes will be scabby. 

 This result was noted upon a j^oi'tion of the plots in this 

 field, principally 1 to 8. The amount of scab, however, was 

 not on the whole serious. 



The Relation vf the Potash to Potato Blight. — As has 

 been stated in the description of the general care given the 

 crop, the potatoes in this field were repeatedly and carefully 

 sprayed with Bordeaux mixture. The dates of the succes- 

 sive applications were as follows: June 27, July 7, August 

 2-3, August 10. Early in August it was noticed that the 

 leaves of all the no-potash potato plants were beginning to 

 blight, while the foliage on all the plots to which potash has 

 been annually applied still appeared to be practically unaf- 

 fected. The blight made rapid progress on each of the five 

 no-potash plots, while the foliage of the vines upon all the 

 other plots for the most part ripened normally. Practically 

 all the leaves on the no-]3otash plots were dead by the end of 

 August, at which date there was still considerable living 

 foliage on the other plots. There was no decay of the tubers, 

 however, on any of the plots; but the marked inferiority in 



