H. W. CAMPBELL 363 
long been in the service of the railroads of the semi- 
arid region, yet it should be said in all fairness 
that the railroads and Mr. Campbell have had for 
their primary object the determination of methods 
whereby the farmers could be made sure of successful 
crops. 
Mr. Campbell’s doctrines of soil culture, based on 
his accumulated experience, are presented in Camp- 
bell’s ‘Soil Culture Manual,” the first edition of which 
appeared about 1904 and the latest edition, consider- 
ably extended, was published in 1907. The 1907 
manual is the latest official word by Mr. Campbell 
on the principles and methods of the ‘‘Campbell 
system.” The essential features of the system may 
be summarized as follows: The storage of water in 
the soil is imperative for the production of crops in 
dry years. This may be accomplished by proper 
tillage. Disk the land immediately after harvest; 
follow as soon as possible with the plow; follow the 
plow with the subsurface packer; and follow the 
packer with the smoothing harrow. Disk the land 
again as early as possible in the spring and stir the 
soil deeply and carefully after every rain. Sow 
thinly in the fall with a drill. If the grain is too 
thick in the spring, harrow it out. To make sure of 
a crop, the land should be ‘‘summer tilled,” which 
means that clean summer fallow should be practiced 
every other year, or as often as may be necessary. 
These methods, with the exception of the subsur- 
