ROOT CROPS. Figs. 774-785.
The growing of roots for stock-feeding has never taken the place in American agriculture that its merits deserve, largely because of the ease and cheapness with which grain crops can be raised and the amount of hand labor involved in the production of roots. There is every indication that the culture of these forage plants will in crease, particularly in the East. The reason why the production of roots is of special interest in the north Atlantic states and in eastern Canada is that these regions raise a comparatively large amount of roughage and a small amount of con centrates, while the north-central states raise a large amount of cereals or concentrates in propor tion to hay and forage as shown in the following table. The following table shows the ratio of con centrates to roughage in the north Atlantic and north-central states according to the Census of 1900 : The significance of this table is further empha sized when the superior feeding value of concen trates is fully understood. For example, experi ments made by Zuntz, of Germany, show that when clover hay was fed to horses, 41 pounds were digested out of each hundred pounds of hay fed, while, when oats were fed, 62 pounds were digested, or 50 per cent more. It was found, however, that it required the energy of 24 pounds of the 41 pounds of hay digested to supply energy to chew and digest the hay, leaving the net nutritive value at 17 pounds. On the other hand, it required only 12 pounds of the 62 pounds of oats to masticate and digest the oats, leaving 50 pounds of oats available for pro ducing energy or work. In other words, the oats had three times the value of the clover hay for the production of work in horses. The energy used up in chewing and digesting food is manifested in heat and helps to keep the animal warm, and is therefore not entirely lost when the ration is merely for maintenance. But since in any liberal feeding for the production of work, the production of meat, or of milk, the amount of heat thus pro duced is sufficient to keep the animal warm, the figures given above may be taken as representing their true food value. Rather extensive Danish experiments indicate that a pound of dry matter in roots is about equal to one pound of the cereal grains, or to three-fourths of a pound of cottonseed meal, when fed to milch cows. Roots, like the cere
als, are highly digestible, perhaps even more digest ible than the cereal grains, and herein probably lies their high value. From the standpoint of the results which they produce, the roots may be looked on as watered concentrates. They have apparently a high net available energy.
The yield of dry matter.
One of the objections to roots as a food product lies in their high water content. This limits the quan tity which may be fed and becomes of special impor tance where they are fed in connection with silage. Because of this high water content it will not be practicable to feed a sufficient amount entirely to take the place of the cereals, even should this he desirable for other reasons. The trend of experi mental evidence is that the feeding value of the dif erent types and varieties of root crops depends more largely on the percentage of dry matter than any other factor ; for example, the percentage of dry matter apparently modifies their feeding value more largely than the percentage of sugar. In comparing these yields with the yields of corn, it must be remembered that it is more difficult to handle a root crop than a corn crop; more hand labor is required per acre and the land must be in good condition. The thorough farmer who manures and fits his land on a timely and intensive system is the one who may succeed in growing root crops.
The following table shows the minimum, average and maximum number of pounds of dry matter per acre which was obtained at the Cornell Experiment Station in 1904, 1905 and 1906, from sowings made in May : Appleton & Co., New York (1892); E. L. Sturtevant, History of Garden Vegetables, American Naturalist (1887, 1888,1S90); Improvement of the Carrot, see L. de Vilmorin, Transactions of the London Horticul tural Society, Ser. 2, Vol. 2, p. 348; John Percival, Agricultural Botany, London (1900); L. H. Bailey, Botany of Turnips, etc., Garden and Forest, 1897, pp., 321, 322 ; James Buckman, Science and Prac tice of Farm Cultivation, London (1865). The most recent studies in this country are by Hunt, Fraser, Gilmore and Clark in Cornell Bulletins Nos. 243 and 244, from which extracts are made above.