A THIRTY-YEAR FERTILIZER TEST. 129 



The plots were 18 by 121 feet in size, or exactly one-twentieth of an 

 acre. A strip 3 feet wide between plots was cultivated as though a part of 

 the adjacent plots, but yields on these strips were never recorded. 



Lime History. 

 Lime was applied in the following amounts : — 



Pounds 

 Year. per Acre. 



1899. Slaked lime . . . 2,000 



1904. Slaked lime, about 3,000 



1907. Agricultural lime, about . . 1,000 



1909. Agricultural lime 2,000 



1916. Ground limestone 4,000 



Precipitation and Frost Records. 



Tables II and III in the Appendix show the observations on tempera- 

 ture, frost and precipitation as taken by the Department of Meteorology 

 of the Experiment Station for the years from 1889 to 1921, inclusive. 



During this thirty-three-year period there have occurred certain fairly 

 definite weather cycles. For a period of eight years, 1897 to 1904, in- 

 clusive, the annual rainfall was consecutively above the mean for the 

 period. From 1907 to 1914, inclusive, with the exception of a single year, 

 the annual precipitation was below the mean of the period, and averaged 

 10 inches annually below that of the preceding period. From 1907 to 1913 

 the rainfall of the growing season, April to August, inclusive, averaged 

 14.7 inches; while for the succeeding seven years the average for the same 

 period was 20.3 inches. There were also in the whole period wide ex- 

 tremes in total precipitation, the least being 10.82 inches for the growing 

 period in 1894, and the highest 32.25 inches in 1892. The growing season, 

 or the time between the last killing frost of the spring and the first killing 

 frost of autumn, varied from 99 days in 1894 to 164 days in 1920. With 

 such wide variations in weather conditions, especially as regards the 

 dominant influence of precipitation, temperature and length of season, it 

 is not to be expected that results from fertilizer use would in all cases be as 

 expected, or show records always consistent one with the other. 



Yields. 



A complete statement of yields is given in Table I of the Appendix. 

 Corn was grown more often than any other single crop, there having been 

 a total of thirteen corn crops. For two years preceding the eleventh crop, 

 however, the land was practically fallow; while the twelfth and thir- 

 teenth crops followed partial or total crop failures. The best picture of 

 results, therefore, may be obtained by considering the corn crop as the 

 common denominator of all the crops, and dividing the corn yields into 

 three periods, including the first five crops in the first, the second five in 

 the second, and the last three somewhat abnormal crops in the third, as 

 shown in Table 1 : — 



