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cause changes in the imported variety, and it may require several years to determine its merits.

Instead of scientific agriculture having "almost reached the limit of its development," it has just fairly begun to develop. This statement is especially applicable to the careful selection of seed. "In Germany, where the percentage of sugar in sugar beets is high, they deem it necessary to adopt the following plan to improve the standard. Ten thousand beets say, all perfect, are selected from a field where the choicest strain was sown and carefully tended. A small section is taken from each beet and tested to determine the percentage of sugar it contains. The hundred beets of the highest quality are selected and planted the next season for seed. The seed from these, is, of course, very valuable, representing hundreds of dollars worth of work, and it is used simply for growing seed beets. From the seed beets thus grown only one hundred of the best are again selected as stock to grow seed beets from, while the rest of the 10,000, though grown from the same strain of seed, are considered only good enough for growing seed for the man who raises sugar, and not sugar beet seed.''' Seed which is good enough for growing beets for seed is considered much too valuable to use in growing beets for sugar. The beet grower has made more progress in this respect in one century than the wheat grower has in many centuries. It should, nevertheless, be said that the improvement in beets was partly the unforeseen result of European legislation. By a peculiar tax, whatever sugar above a certain per cent was extracted from beets paid no tax, or a smaller rate. To increase profits by increasing this excess proved such an additional stimulus to improve the sugar content of beets that the legislators apparently could not modify the laws fast enough to keep pace with the advance.3

While the past importance of introducing new varieties is conceded, it is said that "the time will soon arrive when there will be no further varieties to introduce better than we already have." Unquestionably, the breeding of wheat will have an increasing importance. As wheats may be developed, so they may deteriorate, on account of soil and climate, and in such cases there must perhaps be a periodical importation of seed.

'Proc. TH-State Grain Grow. Ass'n. 1900, p. 170.

2 Handworterbuch der Staatswissenschaften, 7:997-1009.

CHAPTER IV.
CULTIVATION OF WHEAT

SOIL PREPARATION

The cultivation of wheat is coeval with agriculture itself. No land was alone the ground of Ceres where the human race learned to plow and sow, nor was it the task of any one race or nation to tutor mankind in the agricultural arts. How the nations of antiquity tilled, sowed and reaped would be of great interest, but the records which time has bequeathed to us are all but silent upon these homely topics.

Climatic Effects.—The soil in nature is more uniformly covered with vegetation throughout the year than it is under cultivation. Dark, exposed soil absorbs more heat than soil covered with vegetation. Thus cultivation is supposed to moderate climate and there is a widely prevalent opinion that it also lessens frosts, humidity and rainfall.

Plant and Soil Effects.—Soil alterations of the highest importance are made by means of tillage, fertilizing and irrigation. The resulting variations in wheat are quantitative rather than qualitative, except in the case of irrigation, which is practiced on a comparatively small part of the wheat area. This process and that of fertilizing are discussed in later chapters. Cultivation, as here used, refers only to the mechanical operations connected with raising wheat in the natural environment treated in the previous chapter. It renders this natural environment artificial to the degree in which it alters the mechanical arrangement of the soil in nature and eliminates from the competition of life other species of plants which would naturally compete with wheat in the struggle for obtaining the sustenance held by soil and atmosphere. This sets the wheat plant free from many natural conditions which tend to destroy unfit variations and to force wheat to assume one type. Thus cultivation, while it has no direct influence in increasing variation, by removing conditions which exert a selective influence, is indirectly the means by which a greater number of variations survive. In cultivation itself, as above defined, there is no selection. less developed agriculturally and horses in the more developed ones. For example, oxen were preferred to horses in England from 1250 to 1650.

The principal effect of cultivation on the growth of wheat is through its influence upon the physical condition of the soil, to which great importance is attached. By physical condition is meant friability or openness, capacity for absorbing and retaining water and heat, and permeability to roots. Air, which is necessary to the roots, is excluded by hard, water-soaked, baked or puddled soils, and such soils are also impermeable to roots. Stirring or cultivating the soil enables the air to circulate and the roots to penetrate through it. Tillage has been known to increase the yield of wheat over eight bushels per acre.1 Richardson claimed that it increased the nitrogen content of wheat. Generally about 50 per cent of the volume of soils is empty space. That is, in one cubic foot of soil there is about a half a cubic foot of space into which air and water can enter.

The Motor Power first utilized was the muscular energy of man himself. Its application requires the least intelligence. The abundance of human labor, and hence its cheapness, coupled with a lack of intelligence to utilize other forces, are conditions still existing in vast regions of the earth where it is impossible for any other motor power to compete successfully with man himself. India, largely using human labor, often at a cost of but 4 to 8 cents per day, has been so successful in competing with more civilized nations using other forms of power as to assume fourth rank among the wheat raising nations, and to be able to undersell many of them in the world markets. Hand labor is used almost exclusively in raising wheat in China, Japan, Siam, Syria and Colombia, and very extensively in Egypt and parts of Greece, Spain, Mexico, and some of the South American republics.2

Animal Power.—The first one of the forces of nature which man subdued and utilized in relieving himself of some of the drudgeries incidental to agriculture was that of the domesticated beast. There are no marked periods of progress in this. Animal power is by far the most universally used in agricultural operations. As a rule, oxen are found in communities

1 s. C. Bui. 56, p. 12.

'U. S. Daily Consular Repts., Oct. to Dec, 1903.

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Steam.—After nearly two centuries of projection and invention, steam was successfully used for agricultural operations in England in 1832. The system adopted was that of dragging the implements by the aid of pulleys and a cable revolved by a stationary steam engine. This method in improved form is still found in Europe. The movable engine appeared before 1850. In the United States, activity in the invention of steam plows began in 1861, and it was perhaps entirely confined to the use of the traction engine. On the Pacific coast, steam is used quite extensively in the cultivation of wheat, especially on the larger farms. In Germany and Hungary there was about one steam plow to every 10 small plows in 1900. There have also been experiments with electricity as a motor power in agriculture.

Plowing.—The first plow was simply a "sharpened piece of wood or the crotched limb of a tree," and was evolved from the hoe. Some of the earliest plows were drawn by two men, while two others kept them in the ground. The form represented on Egyptian monuments (3,000 B. C.) is an improvement on the hooked stick. Chinese historians say that the first plows in China were made 2,737 B. C. The plow described by Homer was a composite piece drawn by oxen or mules. The early Romans had no cast steel or iron, and their implement was essentially like that of the Germans. The first use of metal on a plow is unknown, but before the time of Christ the Romans yoked the steer to one with a "shining share." The ancient Egyptians and Assyrians had plows pointed or edged with iron. These primitive implements turned no furrow, but simply stirred the ground. Those of the Greeks 2,000 years ago had wheels supporting the beams, and similar forms are found depicted in Saxon manuscripts.

The rude primitive plow seems to have been almost universally the first agricultural implement drawn by beasts of burden. The constancy of the type among different peoples is remarkable. Under uncivilized or frontier conditions it nearly always appears, and its persistence is very great. In the United States plows were worked in Virginia as early as 1617.

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