Fertilizer Treatment 307 
FIGURE II. 
Comparison of Crop Preduction with an Efficiency Factor. 
as 100. The intervening plots Nos. 2, 3, and 4 were then compared to 
this standard. 
This efficiency factor was determined for all plots in a similar 
manner. The graphic crop yields based on a similar method of calcu- 
lation were compared to the efficiency factor in Figure II. It is readily 
seen from this graph that there is a correlation of crop yield with 
biological activities and nitrate production. The closest correlation is 
shown by the oats and timothy yields. The yield of corn shows the 
