In the south of Great Britain rye is chiefly or solely cultivated as a forage-plant for cattle and horses, being usually sown in autumn for spring use, after the crop of roots, turnips, etc., is ex hausted, and before the clover and lucerne are ready. For f or age purposes it is best to cut early, before the leaves and haulms have been exhausted of their supplies to benefit the grain. In northern Europe, and more especially in Scandinavia, Russia and parts of north Germany, rye is the principal bread-corn; and in nutritive value, as measured by the amount of nitrogenous material it contains, it stands next to wheat, a fact which fur nishes the explanation of its cul ture in northern latitudes ill suited for the growth of wheat. It is one of the hardiest of cer eals. The straw, which is prized on account of its length, is used for making hats and in the manu facture of paper. The bran is utilised for cattle-food, and the grain in the distillery. No well marked races of rye are found and the number of fixed varieties is small. Rye is uniform over a very large area.
For further details see W. W. Robbins, The Botany of Crop Plants (Philadelphia, 1924), and R. Percival, Agricultural Botany (1926).
Even as late as 1760, rye formed the general food of one seventh of the British population. In modern British husbandry, however, pure cultures of rye occupy only about 4 ac. in every 1,000 ac. of arable land : it has been almost entirely displaced by wheat, which not only produces corn that is preferred to rye for milling purposes but also yields a heavier crop of grain.
In northern Russia, Germany and Scandinavia, where black bread is still in demand, rye is extensively grown for milling pur poses. This crop can be grown, however, on soils that are too poor, too sour, or too light and dry for wheat production. Rye is also capable of growth and ripening at altitudes and in latitudes that are too cold for other cereals. These characteristics of rye are well exploited in the countries of continental Europe. In Britain, however, rye-growing is not a feature of upland or north erly farming, but the crop is grown to a limited extent on soils too poor for the other cereals.
The straw of rye is remarkable for its length and toughness, hence it is valuable for thatching and for packing purposes, espe cially for saddlery work. For the same reasons rye may be a valu able component of a mixed crop grown for green soiling or for silage, as it supports the climbing leguminous components of the mixture. The earliness of the spring growth of rye is another economic quality of which advantage is taken : rye sown in Sep tember and suitably treated, will yield grazing material in March and April when other green food is scarce.
There are few commercial varieties of rye in Great Britain. Common rye, or rye without varietal description, iS the sort used for autumn sowing where the crop is intended to be harvested for grain. "Giant" is a descriptive name used by seedsmen in respect of an earlier and taller-growing strain that is recommended for straw production or for forage purposes. On the Continent a greater range of varieties is recognized. Special sorts are used for growing in districts that necessitate spring instead of autumn sowing; there are also sorts which may successfully be sown in summer, grazed in the autumn, and then left to be harvested for grain in the following year. The fundamental difficulty in devel oping and maintaining special strains of rye, however, lies in the fact that the plant is mainly cross-pollinated and almost self sterile ; hence new varieties tend to revert to the type common in the district. On account of this mode of pollination, also, rye is
very dependent on suitable weather conditions at the time of flowering, and as the entire head of florets opens at the same time, not gradually and extending over a period of two or three weeks as in wheat, the set of grain is good or bad according to the weather at the time the crop reached the flowering stage.
When cultivated for grain, rye occupies the same place as wheat (q.v.) in the rotation; but it is a better crop than wheat as a suc cessor to other straw crops on poor land or on land that is not very clean. Rye is often grown continuously on outlying parts of German farms. Except that less liberal manuring is required for this crop than for wheat, the general rules for cultivating the two crops are the same. The seed is, however, smaller, and re quires shallower covering and a smaller quantity per acre suffices —typically two bushels when drilling in October. Summer rye is sown in March or April and requires a little more seed. Rye is ripe for cutting about a week or a fortnight earlier than wheat. The yield varies widely, from 12 to 25 cwt. of corn per acre, the quan tity of straw being from two and a half to three times that of the grain. The composition of the grain is very similar to that of wheat, but the straw is more fibrous and less digestible.
Although rye is used extensively in many European countries for bread-making, there is only a comparatively small trade in this cereal in Great Britain. About one-fourth of the small area cropped is grazed or cut green for fodder, and only about 15,000 tons per annum of home-grown rye is marketed. The United King dom imported an annual average of 696,00o bushels of rye in 1925 29 and 494,000 bushels a year in 1930-34. The principal rye exporting countries are Canada, Hungary, Poland, Argentina, Bul garia and Rumania. (J. R. B.; H. C. L., X.) United States.—The production of rye in 1937 was bushels from 3,839,00o acres, the second largest crop since 1927, when the yield was 51,076,000 bushels. In 1935, production was 58,597,000 bushels, the largest since 1922, when a record crop of 100,986,000 bushels was harvested.
Since then annual production has been as low as 17,070,000 bushels, in 1934.
The average annual production of rye was 40,305,000 bushels for 1925-30 and 31,272,000 bushels for 1930-35. Prior to 1928 the United States was a leading exporter of rye, exceeding even Poland. Average annual exports for 1925-29 were 19,063,000 bushels, but in 193o-34 net imports of rye, annual average, were about 2,800,000 bushels. The United States exported 3,889,000 bushels in 1936.
The average yield per acre for 1930-35 was 10.7 bushels. Rye is grown in all parts of the United States. (X.) Hardy varieties of winter (fall-seeded) rye are the most com mon. The date of seeding winter rye varies from late August in the northern parts of North Dakota and Minnesota to October in States south of Kansas. Spring rye is sown as early as soil condi tions permit.
Rye should be sown 1221 in. deep by means of a grain drill.
The customary rate of seeding is pecks per acre in semi-arid regions, 5 pecks in subhumid regions, and 6 in humid or irrigated regions. It should be harvested when the first kernels are ripe. Either a header or a binder may be used. Most of the rye in the United States is threshed with the ordinary threshing machine, though a special machine exists which ensures unbroken straw.
(N. A. C.)