456 INVESTIGATION BY CULTURE EXPERIMENTS 



have been removed, including the grain, hay, straw, and corn 

 fodder, from 1879 to the present time, but records of yields are 

 lacking in some cases. 



Originally, these plots were one half acre each in size, being 5 

 rods wide (north and south) by 16 rods long (east and west), but 

 in 1904, because of the enlargement of the University campus, it 

 became necessary to reduce the length to 9 rods in the central 

 part of the original plots. At the same time one-half rod division 

 strips were established between the plots, also a one-fourth rod 

 cultivated or cropped protecting border around the plotted area, 

 and each of the three plots was also divided in four quarters by 

 half-rod division strips through the center in both directions. 

 Thus, from each of the original plots four plots of one-twentieth 

 acre each have been formed, with half-rod protecting strips. In 

 each case the two plots on the north are continued as a duplicate 

 test of the original system, without the use of manure or commercial 

 fertilizers, while the two plots on the south are cropped the same, 

 but they are now being improved by such applications of farm 

 manure as can well be made from the crops grown, by the use of 

 legume catch crops, applications of ground limestone to correct 

 possible soil acidity, and by the use of phosphorus, applied for each 

 year in the rotation in 200 pounds of steamed bone meal (on the 

 east plot), or in 600 pounds of rock phosphate (on the west plot), 

 per acre. 



The original plot numbers are 'retained, the untreated north 

 part being known as 3N, 4N, and 5N; and the treated south part 

 as 38, 48, and 58, respectively; and to each of these may be added 

 W or E to designate the west or east half. 



InTable 85 are recorded the yields of these old plots for the last 

 twenty-two years, from 1888 to 1909, including, since 1904, for each 

 rotation system, the average of the untreated duplicates and of 

 the treated parts. 



Seasonal influences are so great that no very satisfactory com- 

 parison can be made between different years for the sake of deter- 

 mining the effect of the different systems upon the productive 

 power of the soil, 'and the thorough underdrainage provided for 

 in 1904 must be expected to markedly increase the crop yields in 

 subsequent seasons of excessive rainfall, such as 1907, for example, 



