Mr. Campbell’s doctrines of soil culture, based on his accumulated experience, are presented in Campbell’s “Soil Culture Manual,” the first edition of which appeared about 1904 and the latest edition, considerably 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 subsurface packing, are sound and in harmony with the experience of the great dry-farm sections and with the principles that are being developed by scientific investigation.  The “Campbell system” as it stands to-day is not the system first advocated by him.  For instance, in the beginning of his work he advocated sowing grain in April and in rows so far apart that spring tooth harrows could be used for cultivating between the rows.  This method, though successful in conserving moisture, is too expensive and is therefore superseded by the present methods.  Moreover, his farm paper of 1896, containing a full statement of the “Campbell method,” makes absolutely no mention of “summer tillage,” which is now the very keystone of the system.  These and other facts make it evident that Mr. Campbell has very properly modified his methods to harmonize with the best experience, but also invalidate the claim that he is the author of the dry-farm system.  A weakness of the “Campbell system” is the continual insistence upon the use of the subsurface packer.  As has already been shown, subsurface packing is of questionable value for successful crop production, and if valuable, the results may be much more easily and successfully obtained by the use of the disk and harrow and other similar implements now on the market.  Perhaps the one great weakness in the work of Campbell is that he has not explained the principles underlying his practices.  His publications only hint at the reasons.  H. W. Campbell, however, has done much to popularize the subject of dry-farming and to prepare the way for others.  His persistence in his work of gathering facts, writing, and speaking has done much to awaken interest in dry-farming.  He has been as “a voice in the wilderness” who has done much to make possible the later and more systematic study of dry-farming.  High honor should be shown him for his faith in the semiarid region, for his keen observation, and his persistence in the face of difficulties.  He is justly entitled to be ranked as one of the great workers in behalf of the reclamation, without irrigation, of the rainless sections of the world.