The secret of success in tree growing on dry-farms seems to lie, first, in planting a few trees per acre,—­the distance apart should be twice the ordinary distance,—­and, secondly, in applying vigorously and unceasingly the established principles of soil cultivation.  In a soil stored deeply with moisture and properly cultivated, most plants will grow.  If the soil has not been carefully fallowed before planting, it may be necessary to water the young trees slightly during the first two seasons.

Small fruits have been tried on many farms with great success.  Plums, currants, and gooseberries have all been successful.  Grapes grow and yield well in many dry-farm districts, especially along the warm foothills of the Great Basin.  Tree growing on dry-farm lands is not yet well established and, therefore, should be undertaken with great care.  Varieties accustomed to the climatic environment should be chosen, and the principles outlined in the preceding pages should be carefully used.

Potatoes

In recent years, potatoes have become one of the best dry-farm crops.  Almost wherever tried on lands under a rainfall of twelve inches or more potatoes have given comparatively large yields.  To-day, the growing of dry-farm potatoes is becoming an important industry.  The principles of light seeding and thorough cultivation are indispensable for success.  Potatoes are well adapted for use in rotations, where summer fallowing is not thought desirable.  Macdonald enumerates the following as the best varieties at present used on dry-farms:  Ohio, Mammoth, Pearl, Rural New Yorker, and Burbank.

Miscellaneous

A further list of dry-farm crops would include representatives of nearly all economic plants, most of them tried in small quantity in various localities.  Sugar beets, vegetables, bulbous plants, etc., have all been grown without irrigation under dry-farm conditions.  Some of these will no doubt be found to be profitable and will then be brought into the commercial scheme of dry-farming.

Meanwhile, the crop problems of dry-farming demand that much careful work be done in the immediate future by the agencies having such work in charge.  The best varieties of crops already in profitable use need to be determined.  More new plants from all parts of the world need to be brought to this new dry-farm territory and tried out.  Many of the native plants need examination with a view to their economic use.  For instance, the sego lily bulbs, upon which the Utah pioneers subsisted for several seasons of famine, may possibly be made a cultivated crop.  Finally, it remains to be said that it is doubtful wisdom to attempt to grow the more intensive crops on dry-farms.  Irrigation and dry-farming will always go together.  They are supplementary systems of agriculture in arid and semiarid regions.  On the irrigated lands should be grown the crops that require much labor per acre and that in return yield largely per acre.  New crops and varieties should besought for the irrigated farms.  On the dry-farms should be grown the crops that can be handled in a large way and at a small cost per acre, and that yield only moderate acre returns.  By such cooperation between irrigation and dry-farming will the regions of the world with a scanty rainfall become the healthiest, wealthiest, happiest, and most populous on earth.