54 Maine Agricultural Experiment Station. 1919. 



the potash reduced the yield 6 hundredweight. This is in ac- 

 cord with the results that have been obtained in the so-called 

 no-potash experiments conducted the past 4 years on Cari- 

 bou loam on Aroostook Farm. The application of as little as 

 30 pounds of potash per acre increased the yield about 20 per 

 cent. The application of larger amounts gave no further in- 

 crease. 



These results for the 2 years seem to warrant the tenta- 

 tive conclusions that on Caribou loam on Aroostook Farm 

 while nitrogen is the limiting fertilizing factor, a small amount 

 of potash* is also needed to produce maximum yields. 



The Results from the Plots are Uneven. 



The field selected for this soil test experiment was . care- 

 fully considered before the soil test was begun. The first year 

 the Station had the farm ( 1914) this field was in potatoes. 

 Fifteen hundred pounds per acre of 5-8-7 fertilizer was used- 

 The yield while not very large was apparently even over the 

 whole piece. The next year it was seeded to oats and timothy. 

 The yield of oats in 191 5 and of timothy in 1 91 6 Seemed to 

 be uniform over the piece. The field was plowed soon after 

 haying in 191 6 and the plots were laid out. It was hoped that 

 a detailed soil survey would be made by the experts of the 

 Federal Department of Agriculture. But such a study has not 

 as yet been practicable. A preliminary survey that was made 

 confirmed the opinion formed from the ' 3 crops that had 

 been harvested by the Station as to its probable uniformity. 

 Nothing was known of the treatment of the field prior to its 

 purchase by the State. The former owner carried quite a num- 

 ber of head of dairy animals and applied the manure to the 

 land. This was applied in the convenient, but not from the 

 standpoint of uniform application desirable, way of drawing 

 into piles in the field and later distributing it. Such a practice 



*The fact is well known that during the past few years partial or 

 almost entire crop failures have been experienced on certain other types 

 of soil not only in Aroostook County but in other parts of Maine and 

 the remainder of New England as well, where no-potash fertilizers 

 have been used for potatoes. In Aroostook these crop failures due to 

 lack of potash are almost wholly confined to the Washburn loam or 

 closely related soils. 



