Fundamental Principles.— The principles that have been developed have undergone an evolution. It was at first believed by many that spring plowing was most advantageous, so as to open up the soil for moisture, but it developed that the best results were had by fall plowing, which allowed the snow and water to gather and lie in the furrows through the winter, and to follow with regular cultivation in the spring, especially after rains. It also developed that deep plowing secured better results than shallow plowing, and that the sooner after harvest the plowing was done, the more moisture was con served.
As soon as the crop is harvested, in fact on the same day, the stubble should be disced so as to again create a mulch and check evapora tion from below. When a hot July sun falls upon the open surface of a grain field that has been protected by the grain itself from the sun's direct rays for so long, the rapidity with which moisture leaves the soil and is absorbed by the atmosphere is incredible. As soon as possible after the work of discing has been completed the field should be plowed to a depth of eight or nine inches, the sub-surface packer again brought into use, the surface harrowed, and the crop planted.
Late winter seeding is now strongly urged, and is becoming the established practice. It has been demonstrated that thin seeding is far bet ter than strewing plenty of seed, on the theory that the plants, having scanty moisture to draw upon, should not be crowded.
In western Kansas and Nebraska and east ern Colorado and northern New Mexico fall wheat should be sown from the 1st till the 20th of September. Early the following spring the field should be harrowed several times till the wheat is large enough to shade the ground well. A light steel frame harrow with levers to ad just the teeth should be used and the teeth should be set so they will lie nearly flat This work of harrowing will not, as many suppose, destroy the growing wheat plants. On the con trary,. it loosens the surface, increases the rapidity of the movement of moisture to the roots of the plants and checks evaporation at the surface due to the creation of the soil mulch, and at the same time puts the soil in such condi tion that it rapidly drinks in whatever moisture falls. For it is apparent that a much larger percentage of a rainfall will enter into the sub surface of a field when the surface is loose than when it is hard and packed.
Experiment The United States Department of Agriculture has established a series of experiment stations for testing methods and problems connected with dry farm ing; several of the semi-arid States have made appropriations for assisting the work; the Agri cultural Colleges have lent their aid and ad vice; and a number of the great western rail way companies have contributed funds to as sist the scientific study of farming in these regions where the rainfall is slight and where artificial irrigation is impracticable. The dry farming experiment stations are increasing in number, as their value is shown. Utah has six, supported partly by the State and partlya the Federal government. It costs about $3, a year to run a station, which is virtually a small farm, managed by an educated man, usually a graduate of an agricultural col lege, whose time is devoted to whatever lines of experiment are laid out for him. The Depart ment of Agriculture, which guides the work of these experiment stations, bends its energies mainly to soil management, cereal investigation, plant breeding, meteorological research, soil moisture determination, and bacterial studies.
The bureau of plant industry has been of great assistance, and the more hardy cereals have been determined, and are generally utilized. Very numerous tests have been made of foreign cereals, known to do well on poorly watered soils.
Those types of seed that have proven themselves drought-resistant are selected. What is known as the durum wheat, imported from the semi-arid regions of Russia, or the turkey red winter wheat, are the varieties that thrive best. Kherson oats, bald barley, emmer, proso, brome grass and native blue stem are all es pecially well adapted to the soil and climatic conditions that prevail west of the 97th meri dian.
To protect crops in flat regions, Gifford Pinchot strongly urges the planting of several rows of trees at intervals as windbreaks. This tends to decrease evaporation in the vicinity as well as affording a safeguard in heavy wind storms.
The following out of the theories thus scientifically developed has accomplished splen did results in Utah, Colorado and Montana, where there are large areas of unirrigated lands that have been utilized by dry farming methods. A great deal of land, formerly held to be un saleable, or offered at the nominal price of 50 cents or $1 an acre, has risen in value to $5 and $10 an acre simply because of the demonstration of successful dry farming in the vicinity. In Colorado, with only a foot of annual rainfall, the 1915 wheat crop was over 12,000,000 bushels, the corn crop was nearly as great, and the oats production attained 12,600,000 bushels, while the hay crop of ,238,000 tons was worth $17, 000,000. Utah, with 16 inches of rainfall, has an annual production of over 8,000,000 bushels of oats and $8,500,000 worth of hay. Montana, with a rainfall of 13 to 19 inches, produced in 1915 26,000,000 bushels of oats and nearly 31, 000,000 bushels of wheat, besides over $15,000, 000 worth of hay. Such results speak volumes for intelligent methods.
Dr. John A. Wiltsoe, president of the State Agricultural College of Colorado, and author of the arid-farm law of Utah, advises that profitable farming by dry methods should be possible anywhere with 12 or more inches of rainfall. He is a strong advocate of deep plowing in the fall, and emphasizes the im portance of cultivation of the soil in the early spring and after every rain, in order that the moisture may be well distributed and carry the plant food where it can be reached by the young rootlets. He mentions wheat, oats, bar ley, rye and lucerne as the crops that yield best returns on dry soils.
A few years ago the government of British South Africa sent William Macdonald on a tour through the semi-arid regions of the United States to study dry farming, and report whether the methods used here were applicable to South Africa, where there is much semi-arid land. Mr. Macdonald was intensely impressed with the accomplishments here, and wrote an en thusiastic report to his home government, com mending the of annual dry farming congresses as is done in the States; advising the establishment of five dry farm experiment sta tions in 'Pretoria, modeled after the American stations; and urging the scientific study of crops suitable for South African soils.