44 EXPERIMENT STATION. [Jan. 



pendent of a supply of iiiiniediat'ely available phosphoric acid. 

 The result with potatoes offers a striking contrast to the result 

 obtained in 1908 with cabbages, with which the crop on some of 

 the best jihosphate plots was more than six times greater than 

 that produced on the no-phosphate plots. 



(2) Although the phosphate used affected the total yield 

 but little, it was noticed that during the first few weeks of their 

 growth the vines on the plots to which the more available phos- 

 jihates had been applied (phosphatic slag, dissolved bone black, 

 dissolved bone meal and acid phosphate), made a much more 

 rapid growth than on the other plots. The use of a little phos- 

 phoric acid, therefore, in highly available form, seems likely to 

 prove a distinct advantage by pushing the crop more rapidly 

 forward, so that it may better resist attacks of insects or un- 

 favorable conditions which may occur later. It seems likely, 

 further, that where the crop is cultivated for an early market the 

 use of moderate amounts of highly available phosphoric acid 

 may prove beneficial. 



(3) The potatoes produced on the plot to which phosphatic 

 slag has been annually applied for so many years were very 

 scabby, although the seed planted was treated with formalin, 

 as was that planted on the other plots also. So serious was 

 this trouble that the market value of the crop was very greatly 

 reduced, and the conclusion appears justified that a free use 

 of phosphatic slag in the same season that land is to be planted 

 with potatoes must in general prove highly undesirable. Slag 

 meal is a strongly alkaline fertilizer, and this is undoubtedly 

 the cause of the very scabby crop produced, since the scab 

 fungus is known to be most troublesome in soils which are 

 alkaline. 



VI. Manuee Alone compaeed with Manttee and Sulfate 



OF Potash. 

 This experiment, which occupies what is known as the south 

 corn acre, has been in progress since 1890. The field is divided 

 into four plots of one-fourth acre each. Good barnyard manure 

 from milch cows, at the rate of 6 cords per acre^ has been ap- 

 plied annually, with the exception of those years when it was 



