Nitrogen may be obtained by applying sixteen grams of dried blood or twelve grams of nitrate of soda; phosphorus by applying twenty-four grams of acid rock phosphate or dissolved boneblack; and potassium by applying four grams of potassium chloride. The fertilizers should be thoroughly mixed with the soil to a depth of six inches.

433 INFLUENCE OF SIZE OF SEED ON EARLY STAGES OF PLANT GROWTH.Divide sample of oats into large, medium and small grains. This may be done by hand selection or by means of a nest of sieves. Obtain weight of fifty grains of

On the right, a nest of sieves for cleaning seeds; on the left, sieves with holes of various sizes, forms and positions. For further information see U. S. Dept. of Agr. Yearbook 1894, p. 406.

each and plant under similar conditions either in the field or in the plant house, taking care to cover the seeds a uniform depth. If in pots or trays in pot house, the soil can be removed more easily from the roots.

Note time required for plants to come up and number of plants produced. Obtain average height at end of each week. At end of three or four weeks, depending upon growth, obtain fresh and water-free weight of each lot of seedlings. Make sketches of the more important differences in roots and leaves of the different lots, if any.

434. INFLUENCE OF TREATMENT OF SEED UPON GERMINATION.-Having carefully graded a sufficient quantity of oats, treat fifty grains each of the following ways:

1. Nothing.

2. Immerse in water at 70° F. for four hours.
3. Immerse in water at 70° F. for ten minutes.
4. Immerse in water at 133° F. for ten minutes.

5. Immerse in water at 70° F. for forty hours, and then at 70° F. for five minutes

6. Immerse in one-fourth per cent solution of formalin for thirty minutes.

7. Immerse in one-half per cent solution of formalin for thirty minutes.

8. Sprinkle with No. 6 solution without immersing.

9. Immerse in two per cent solution of copper sulphate for ten minutes. 10. Nothing.

After treatment all lots are to be dried as much as they would need to be in order to be sown in a grain drill. Place in germinator at 70° F. and determine the number of seeds which have germinated at the end of twenty-four hours for five days. (475) Lots of seed may also be grown as in (433).

435. COLLATEral Reading.

The Leading Cereal Crops in Canada. By Wm. Saunders. Experimental Farris Rpt. 1903, pp. 6-33.

Farm Manure. By A. Hebart. E. S. R. V, pp. 139-158.

Origin of Cultivated Plants. By A. De Candolle. New York: D. Appleton & Co.

(1902), pp. 373-376.

XXI.

BARLEY.

1. STRUCTURE AND COMPOSITION.

436. Relationships. - Barley (Hordeum sativum Jensen) belongs to the same tribe as wheat and rye, and differs from both in that the spikelets are one-flowered, and in having more than one spikelet at the joint of each rachis.

437. The Plant.—Aside from the spike, the barley plant has much the same appearance and habit of growth as wheat. Usually the culms are not so tall, and are perhaps more variable on account of environment. Wisconsin Station found with several varieties during five years an average of one pound of straw for each pound of grain, there being considerably less straw than is usually obtained with wheat or oats. In a comparative trial the proportion of top to root in weight of dry matter was 3.3 to one in barley and 2.2 to one in oats. The indication is that it is more shallow rooted than wheat, maize or oats. Although the roots grow rapidly, they are comparatively feeble and short lived.

438. The Inflorescence. The spikelets are one-flowered, sessile, thus forming a spike. The outer glumes are almost awishaped, three-eighths inch long with flexible beard one-half to three-fourths inch long. Flowering glume, which with palea is adherent to fruit, is prolonged into a stiff beard six to eight inches long with strongly barbed edges, making barley a disagreeable crop to handle, although the objection to the beards

1 Wis. Rpt. 1903, p. 268.

2 Wis. Rpt. 1892, p. 119.

has been considerably lessened by the introduction of the selfbinding harvester, and in the Western States by the header and combined harvester and thresher. As there are three spikelets at each joint of the rachis, each joint bears six outer glumes. There are three stamens and a double feathery stigma similar to wheat. In the six-rowed type there are three spikelets at each joint of the rachis, and these joints are close together, thus forming a square, rather compact spike, which may be four or six-rowed, depending upon whether or not the side rows overlap.

439. The Grain. The barley kernel, like the oat kernel, remains enclosed, except in hull-less varieties, in the flowering glume and palea, from which it is with some difficulty removed. These parts are called the hull, sometimes the husk. In this book the caryopsis of the barley will be called the kernel, and the kernel plus the hull will be called the grain. (388) Although the grain of barley is quite different in appearance from

0004...

Selected grains of barley, natural size
(After Hicks and Dabney.)

a grain of wheat, when the hull is removed the resemblance is quite close, having like wheat a deep furrow on the side opposite the embryo. It is somewhat broader, with sides more rounded and upper end more pointed.

Barley grains are a little wider than thick, varying from onefifth to one-tenth of an inch in width, one-seventh to one-twelfth of an inch in thickness, and from one-fourth to one-half of an inch in length. The word barleycorn is sometimes used as a measure of length, meaning one-third inch. The weight of 100 grains varies from 2.5 to five grams, the average being about 3.5 grams, or about 1.300 grains to the pound. In the sixrowed barley the lateral grains are slightly smaller than the central ones. Two-rowed varieties have plumper and longer

grains than six-rowed varieties. Grains coming from the Rocky Mountain and Pacific Coast States are likewise longer and plumper than those from the North Central and North Atlantic States.

440. The Hull.—The hull or husk of barley may constitute less than ten per cent or as much as twenty-five per cent of the grain. The average is probably about fifteen per cent, or half that of the oat grain. Grains of the six-rowed barley have thicker hulls than the two-rowed barley. The hull of barley is of value in the process of malting by protecting the embryo during germination and subsequently acting as a filter when the malt is extracted. The rudiment of the second flower is attached at the base of the flowering glume and lies almost concealed in the furrow next the palea. This feathery appendage about half the length of the grain is said to be a ready channel for the conveying of moisture to the kernel.

441. The Character of the Endosperm.-The endosperm varies in texture (not structure) and color from mealy white to glassy or vitreous. (238) The character of the endosperm varies with (1) the variety, the two-rowed being more mealy than the six-rowed; with (2) the maturation, fully but not overripe grains being the most mealy; and with (3) the climate, a moist and insular climate being most conducive to complete maturation. (74) As in wheat and maize, a glassy or translucent endosperm is accompanied by high percentage of protein and a corresponding decrease of starch. The character of the endosperm may be determined by cutting the grain across with a sharp instrument. In an average of thirty-six samples of American barley, Wahl and Henius report sixteen per cent of the grains mealy; fifty-two per cent half glassy, and thirty-two per cent glassy. The character of the endosperm may also be determined by placing the grains of barley by suitable contrivance between the observer and a strong light, when the number of opaque, partly opaque and translucent grains may be determined.