It is not possible to make accurate compari sons as to composition of wheats grown in dif ferent countries. It will frequently be found that wheats grown in different localities of the same country vary as much in composition as do wheats grown in different countries.
Wheat contains slightly more protein and less starch than corn, oats, rye or barley. Oats from which the hulls have been removed con tain more protein and fat than wheat. The difference in composition between wheat and the other cereals is not large and occasionally indi vidual samples of corn or rye will be found containing more protein than individual samples of wheat. Wheat differs in composition from all other cereals in that its gluten is composed of the two proteids, gliadin and glutenin. This gives flour its bread-making value. It has also been found that the wheat proteins contain both different kinds and amounts of anitno acids from the proteins of other curds. No other cereal except rye contains a gluten that is capa ble of expanding and forming a light porous loaf. Because of its unique composition no other cereal can take the place of wheat for bread-making purposes.
Numerous experiments have been made to improve the quality of wheat by selection of seed, and by breeding and crossing of standard varieties. Wheat responds readily to such tests, but unless great care is taken it as readily re verts to its original condition. In the United States two main classes of wheat are produced, namely : winter and spring wheat, of which there are a member of varieties, as white and red winter wheat, 'Turkey Red," Oregon Club, Blue Stem, Scotch Fife, Marquis, etc. Minnesota, North and South Dakota, and Montana consti tute the main spring wheat region: spring wheat is, however, grown in other localities.
The wheat plant assimilates its mineral food and nitrogen from the soil at a rapid rate. In the case of spring wheat, by the time the crop is half grown, over three-fourths of the min eral food and nitrogen needed for construction purposes have been taken from the soil. Wheat is not a strong feeding plant and taking its food from the soil in so comparatively short a time, the soil must be in a high state of pro ductil mess in order to yield a good crop. The
wheat plant needs greatest assistance in securing its nitrogen, hence fertilizers for wheat should be nitrogenous in character. Wheat also needs a good supply of available mineral food as phos phoric acid and potash, but is better able to secure these elements from the soil than it is nitrogen..
The flour yield of wheat is determined ap proximately from the size and weight of the kernels. Light weight wheat has a low flour content.
Because of its usually high price, wheat has never been extensively used as animal food, but at times when it has been cheap and abundant, it has been used for the feeding of all farm animals and has proven equally as valuable as other grains for the production of beef, pork, mutton and milk. In the feeding of wheat to farm animals, the best results are secured by coarsely grinding or pulverizing the grain in stead of feeding it whole. The main use of wheat, however, is to manufacture flour for hu man food. It is used more extensively as human food than any other cereal.
It has been found from extensive experi ments conducted by the United States Depart ment of Agriculture that the highest degree of digestibility and nutritive value of wheat are secured when the bran and indigestible fibre are removed from the flinty portions of the kernel. The human digestive tract is unable to digest wheat bran; animals, however, with greater digestive powers are capable of doing so. Wheat produces one of the cheapest, most nutritious and most wholesome of foods.
Bibliography.— Dondlinger. P. T., 'The Book of Wheat' (New York 1908); Hunt, T. F., 'The Cereals in America' (ib. 1904); Rutter, W. P.. 'Wheat-Growing in Canada, the United States, and the Argentine, including Comparisons with Other Areas' (London 1911) : Smith, R. E., 'Wheat Fields and Mar kets*.of the World' (Saint Louis 1908); Ten Eyck, A. M., 'Wheat : A Practical Discussion of the Raising. Marketing. Handling, and Use of the Wheat Crop, relating largely to the Great Plains Region of the United States and Canada' (Lincoln, Neb., 1914) ; also Bulletins of the United States Department of Agriculture, Nos. 534, 5%, 616, 678, 680, etc.