modern plow should not be replaced by some machine even more suitable for the proper turning and stirring of the soil.  The moldboard plow is, everything considered, the most satisfactory plow for dry-farm purposes.  A plow with a moldboard possessing a short abrupt curvature is generally held to be the most valuable for dry-farm purposes, since it pulverizes the soil most thoroughly, and in dry-farming it is not so important to turn the soil over as to crumble and loosen it thoroughly.  Naturally, since the areas of dry-farms are very large, the sulky or riding plow is the only kind to be used.  The same may be said of all other dry-farm implements.  As far as possible, they should be of the riding kind since in the end it means economy from the resulting saving of energy.

The disk plow has recently come into prominent use throughout the land.  It consists, as is well known, of one or more large disks which are believed to cause a smaller draft, as they cut into the ground, than the draft due to the sliding friction upon the moldboard.  Davidson and Chase say, however, that the draft of a disk plow is often heavier in proportion to the work done and the plow itself is more clumsy than the moldboard plow.  For ordinary dry-farm purposes the disk plow has no advantage over the modern moldboard plow.  Many of the dry-farm soils are of a heavy clay and become very sticky during certain seasons of the year.  In such soils the disk plow is very useful.  It is also true that dry-farm soils, subjected to the intense heat of the western sun become very hard.  In the handling of such soils the disk plow has been found to be most useful.  The common experience of dry-farmers is that when sagebrush lands have been the first plowing can be most successfully done with the disk plow, but that after. the first crop has been harvested, the stubble land can be best handled with the moldboard plow.  All this, however, is yet to be subjected to further tests.

While subsoiling results in a better storage reservoir for water and consequently makes dry-farming more secure, yet the high cost of the practice will probably never make it popular.  Subsoiling is accomplished in two ways:  either by an ordinary moldboard plow which follows the plow in the plow furrow and thus turns the soil to a greater depth, or by some form of the ordinary subsoil plow.  In general, the subsoil plow is simply a vertical piece of cutting iron, down to a depth of ten to eighteen inches, at the bottom of which is fastened a triangular piece of iron like a shovel, which, when pulled through the ground, tends to loosen the soil to the full depth of the plow.

The subsoil plow does not turn the soil; it simply loosens the soil so that the air and plant roots can penetrate to greater depths.

In the choice of plows and their proper use the dryfarmer must be guided wholly by the conditions under which he is working.  It is impossible at the present time to lay down definite laws stating what plows are best for certain soils.  The soils of the arid region are not well enough known, nor has the relationship between the plow and the soil been sufficiently well established.  As above remarked, here is one of the great fields for investigation for both scientific and practical men for years to come.