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in the yield has been obtained. In a number of experiments the influence of the number of seeds per acre has not been eliminated.
If the grains of the spikelets of wheat be designated by numbers according to the distance from the spikelet, it has been found that grains occupying the second place are the heaviest; that those in the first and the third place are about equal in weight; while grains in the fourth and the fifth place, if any, are still lighter. It is also found that of grains occupying the same relative position, those on the lower half of the spike are the larger. The following table gives results with two varieties of wheat:1
It would thus appear that small and large grains come from the same plant, varying in size because of their position, as do the grains of maize on the ear. If the plant and not the individual seed is the unit of reproduction, small seeds from productive plants will be better than large seeds from unproductive plants, provided productivity is due to heredity and not to environment, except in so far as large seeds may give the plant a more vigorous start in life. (43) It has been shown, however, that on an average, the larger spikes contain the larger grains, so that in selecting the larger grains the larger number of them would come from the larger spikes.?
134. Treatment of Seed.—Before sowing, the seed should be carefully screened in a fanning mill, or wheat grader, or
1 Kurt Rumker: Jour. of Landw. 38 (1890), p. 309. 3 Seed Wheat, pp. 1-60: Sidney, 1903.
preferably both, not only to eliminate all small and unde veloped grains, but to remove weed seeds and diseased grains, if any.
If seed comes from plants that have been affected with stinking smut (149), the seed should be immersed in cold water and
stirred, when the smut balls will rise to the surface and can be skimmed off. The seed should then be sprinkled or immersed thirty minutes in a solution of formalin mixed at the rate of fifty gallons of water to one pound of formalin (forty per cent solution of formaldehyde).
Blue stone solution or hot seed wheat grader suitable for use by wheat water may be used in place growers. Wheat is sorted according to size of grains and not according to specific gravity.
of the formalin. (149) In The screen is a cylinder of perforated sheet case wheat has been af. metal, actuated by the crank E. A brush, AA, an important feature, is held against the screen fected with the loose smut by the springs, BB. Meshes ranging from two the wheat may be given to three millimeters may be used; where only one size is supplied, 2.5 millimeters (one-tenth the modified hot water inch) should be used for American wheat. (After treatment. (148) It is Cobb.)
necessary in such case to use one-half more seed to replace seed injured by treatment. Since loose smut is usually not very destructive, it will probably be rarely advisable to resort to treatment of seed for loose smut.
135. Wheat Seeding Machinery.—For broadcasting small areas, the hand grass seeder will do satisfactory work when it is not too windy. The usual horse broadcast seeder is not unlike the wheat drill, except the wheat is scattered directly from the hopper onto the surface of the ground instead of being conveyed by means of hoes underground. Standard widths are eight,
The broadcast grain seeder,
eleven and fourteen feet. The wheat drill is made in three general forms : (1) hoe drills, (2) disk drills, and (3) drills with runners or shoes. The drill with runners also usually has a wheel behind each runner which is designed to press the earth firmly about the seed. Wheels are also sometimes used on disk drills. Where these wheels are used they are known as press drills.
The first form of drill is made with shovels, called hoes, which open the ground and permit the seed to be introduced in a stream into the soil behind each hoe. The hoe drills will operate
under a larger number of conditions, but are heavy of draft and are liable to clog when the soil contains much rubbish. The disk drills draw easier, and are not so liable to be clogged with rubbish, but are not so well adapted to stony or hilly land and will not work so well in wet soil. The drills with runners
have not been extensively Grain drill. Three methods employed in opening
employed. The hoes are the soil for the introduction of the seed are
made so as to run either
seven or eight inches apart. When the hoes are seven inches apart, nine, ten and eleven hoes, and when eight inches apart, six and eight hoes, are standard sizes.
There is no evidence to show that one width of seeding is better than another. Eight-inch drills are less liable to clog
with rubbish than seven-inch, although the zigzag arrangement on both sizes lessens the importance of this difference.
Wheat drills may be purchased with and without grass seeder attached, and with and without fertilizer drill. The grass seeder
scatters the seed broadcast either in front or behind the drills as preferred, while the fertilizer is conveyed into the ground by the same channel as the grain. There are a number of different methods of conveyirg the
grain and the fertilizers from their The hand seeder. respective hoppers, most of which are
satisfactory. Those forms which vary the amount sown by means of variation in the sizes of cog wheels used are probably the best. These drills are usually intended to sow the seeds of all ordinary field crops.
136. Cultivation.—The cultivation of wheat much as we cultivate maize in this country was formerly vigorously advocated and somewhat practiced in England. This practice has never been common in the United States, and only one station (Alabama) out of seven which have reported trials has found it beneficial as compared with the usual method. In most cases it has been found decidedly detrimental. A number of stations have reported in favor of harrowing wheat drilled in the ordinary manner one or two weeks after seeding. The Ohio Station reports that harrowing winter wheat in the spring did no harm.
137. Rolling.–Winter wheat may be rolled in the spring, when there is much heaving of soil, in order to pack the soil about the roots. The cost of thus smoothing the surface may often be repaid by the increased facility with which the crop can be harvested. When grass seed is sown with the grain, rolling should never be neglected.
I. WEEDS, FUNGOUS DISEASES AND INSECT ENEMIES.
138. Weeds.—A great variety of weeds occur in the wheat field which may reduce the yield or injuriously affect the quality of the grain. In general they are to be avoided by those conditions which best promote the growth of wheat, and by sowing wheat that is free from foreign seeds. · There are a few species of plants that are so associated with the raising of wheat as to deserve special mention. The presence of a considerable quantity of any of these weeds in a wheat field must, of course, somewhat reduce the yield of wheat. But the principal injury, perhaps, is in the reduction in the quality of the grain, due to the presence of the weed seeds.
(1) Chess or cheat (Bromus secalinus L.) (2) Darnel (Lolium temulentum L.)
Cockle (Agrostemma githago L.) (4) Wild garlic (Allium vineale L.) (5) Wheat-thief (Lithospermum arvense L.)
139. CHESS.—Chess belongs to a different tribe (Festuceae) of the grass family from that of wheat (Hordeae), which includes, also, some of our best known pasture and meadow grasses. It is an annual and so closely resembles wheat while young as not to be distinguished from it by the ordinary observer. It will stand more cold than the wheat plant, is not attacked by insects especially injurious to wheat, is a less vigorous grower than the wheat plant, but is much more prolific than wheat when its development is not prevented by the growth of the more vigorous wheat plant. The author sowed one pound of chess on one-twentieth of an acre and reaped ninety-nine pounds of seed. A single plant has been known to produce 3,000 seeds. The seeds which adhere to the paleae are so small that a pound of chess may contain as many seeds as a bushel of wheat. Experiment has shown that chess seed will grow when sown, and that the young plants can be distinguished from wheat plants. It has also been shown that when wheat only is sown in clean ground only wheat is obtained; that when wheat and chess are sown both wheat and chess