SULFATE OF AMMONIA. 



87 



The crop of 1906 followed the 1905 crop of oats and peas when the 

 land was limed. The sulfate of ammonia ])lots produced about 20 per 

 cent more weight than the plots without nitrogen. In 1911 the corn 

 followed four successive years of hay production, including some clover, 

 and an application of lime over the east half of the plots in the fall of 

 1909. The yields without nitrogen exceeded those with ammonia by a 

 small amount, between 2 and 3 per cent. Corn was raised again the next 

 3''ear, and the results were changed, the ammonia plots producing about 

 7 per cent more weight. The spring months of 1911 were dry, also June 

 and July of 1912. In 1918 corn was the last crop of this period. It had 

 been preceded by potatoes in 1917, millet in 1916 and clover in 1915, 

 previous to which (in 1913) the east half of the plots had been heavily 

 limed. The crop from the limed and unlimed areas was harvested sepa- 

 rately. In the presence of lime, the ammonia plots produced an increase 

 of 28 per cent over the no-nitrogen plots, while without lime they were 

 slightly inferior to the plots without nitrogen. 



Table III. — Average Yield of Corn {Ears and Stover-) (Pouvds per Acre). 



1 After oats and peas with lime. 



- After clover with lime applied to half area. 



3 Last limed in 1913 over half area. 



Oats. — Seven crops of oats were grown during the years covered by the 

 experiment. The first crop (1890) followed the continuous corn culture 

 practiced for seven years. The next three crops (1893, 1895, 1897) 

 alternated with crops of soy beans. In 1898 the crop followed the oats 

 of 1897, but the land was limed before seeding at the rate of 2,000 pounds 

 per acre of air-slaked lime, and the oats were sown as a nurse crop for 

 clover. In 1905 oats were combined with field peas and followed a crop 

 of potatoes, and the land was again limed at the rate of 2,000 pounds of 

 air-slaked lime per acre. Up to this point the land had been plowed 

 every year since 1883, except 1899. In 1914 oats were sown as a nurse 

 crop for clover, after three years of tilled crops, — two of corn and one 

 of Japanese millet. The east half of the plots had been limed in 1909 

 and 1913. The last two crops of oats were cut for hay and the others 

 were permitted to ripen the grain. The rainfall in 1890, 1893 and 1895 

 had been well distributed during the months of growth, and was about 

 normal in amount. 



