240 MASS. EXPERIMENT STATION BULLETIN 194. 



of soda indicated by plots 2 and 3 is contradicted by the results from 

 plots 31 and 34 when they are compared in like maimer. The soil con- 

 ditions on the latter plots have been already mentioned and should be 

 taken into account. Its poorer quality may have offset the increased 

 amount of nitrate. 



The relative effects of manure and chemicals were compared on plots 

 13 to 16, and the comparison may also be extended to plots 11 and 12 

 adjacent to 13. The best interpretation of the results is to say that 

 manure alone and chemicals alone were equally effective, and that the 

 respective quantities of each were sufficient for the soil conditions in 

 producing a crop. There is also no appearance of any cumulative 

 effect of the manure in increasing the crop. The gains of 1914 over 1910 

 were as follows: plot 11, 72 per cent; plot 12, 74 per cent; plot 13, 82 

 per cent; plot 15, 74 per cent; plot 16, 79 per cent. This is of interest 

 when one considers the sandy soil and low humus content. 



Table III. — Chemicals supplying Nitrogen, Phosphoric Acid and Potash 

 in Connection with Manure (Pounds). 



Plots 21 to 30, inclusive, were fertilized to determine the value of nitrate 

 of soda as a top-dressing in addition to an application of 10 tons of manure. 

 The value of the added nitrate was rendered questionable by the rust 

 which has been shown to have severely reduced the yields of plot 21 even 

 in 1914, when most plots had apparently recovered. The yield on plot 

 13, receiving manure alone, was increased 82 per cent in 1914 over the 

 yield in 1910. If the 1910 yield of plot 21 is increased by 75 per cent and 

 compared with the actual yield in 1914 it is seen to be 415 pounds instead 

 of 373.8, which would bring it up to a full equaUty with the yields of the 

 plots which received nitrate of soda. The economy of the added nitrate 

 is made doubtful. 



