1194 
Journal of Agricultural Research 
Vol. XXXI, No. 12 
Spring Wheat 
For spring wheat Figure 1 shows but little difference in the moisture 
content of the plots continuously cropped and those growing spring 
wheat alternating with fallow. The difference up to June 28 is not 
sufficient to cause any difference in the rate of growth. It must be 
noted, however, that after June 28 there was a more decided drop in 
the moisture content of the alternate fallow and crop plots than in the 
plots continuously cropped. It is quite possible that the greater 
/**77e& o/ !r &*s//v./A/0 
Fig. 1—Moisture content of the soil in several plots at different periods of plant growth 
growth of the spring wheat, as shown by the yields, brought about 
this change. If this be true, then it is quite certain that some factor 
in addition to moisture was responsible for the difference in plant 
growth. This difference can not be attributed to any difference in 
climatic conditions. A study of Figure 2 shows that the summer- 
fallowed plot contained much more nitrate nitrogen than the plot 
continuously cropped. In Table III the plot yields are calculated to 
bushels per acre, and -these calculations show that the average of 
seven years’ yield of winter wheat is 24 bushels on the continuously 
cropped land and 40 % bushels on the alternate fallow and cropland. 
