90 



MASS. EXPERIMENT STATION BULLETIN 204. 



Of the plots receiving ammonia, No. 8 made the poorest j^ield year 

 after year without regard to kind of crop. In 1897 and 1898 the seasons 

 were excessively wet, and plot 8 equaled or exceeded the other plots. It 

 has been mentioned that this plot has appeared to be a little drier than 

 the remainder of the field, which accords with its variable yields in the 

 different seasons. 



The sulfate of ammonia was beneficial in each year, but in 1893, a j^ear 

 of well-distributed average rainfall, the plots without nitrogen yielded 

 their maximum crop and nearly equaled the yields of the ammonia plots. 

 In 1897 and 1898 the ammonia produced marked increases in jdelds under 

 adverse conditions of heavy rainfall and wet soil. 



Table IV. ■ — Average Yield of Oats {Grain and Straiv) {Poimds per Acre). 



1 Limed in 1898 and 1905 over whole area, and in 1909 and 1913 over half area. 

 = Harvested as hay. 



Soy Beans. ■ — Five crops of soy beans were grown in this experiment. 

 Three of them (1892, 1894 and 1896) alternated with grain crops and 

 were cut and weighed green. The season of 1894 was extremely dry, with 

 but 9 inches of rain from April 1 to October 1; consequently the yield 

 in this season was much less than in the other two, when the rainfall was 

 about normal. Plot 8 was given a light dressing of lime in 1894, which 

 resulted in maximum yields on this plot in both 1894 and 1896. 



The other two crops were grown in 1901 and 1903 and followed potatoes 

 in each case. In 1898 the field had been limed over its entire area. The 

 two crops ripened their seed, and the weights of the combined straw and 

 beans are given. The rainfall was abundant as a whole, but June, 1901, 

 and May, 1903, were each dry months, and may have influenced the 

 yields somewhat. 



In the earlier period sulfate of ammonia produced a marked effect on 

 the crops, reaching a maximum of nearly 60 per cent increase in 1896. 

 The crops of the second period were benefited but little by the am- 

 monia. Probably by this time the soil had becom.e naturalh^ inoculated 

 with the soy bean bacteria for fixing nitrogen from the air, for the soy 

 beans grew nearly as well on the plots without nitrogen as on those which 

 received sulfate of ammonia. In 1901 it was recorded that nodules were 

 abundant on the roots. 



