174 The Principles of Agronomy

wheat has spread rapidly into drier districts until it is

the principal crop on the dry-farm. It is only of late

years that crops of higher acre returns have driven it

from irrigated farms.

Whether a crop yielding at he.st only a few doUars to

the acre can be profitably grown on high-priced land is

Fig. 60. — Wheat fanoa should be large to be most economical.

questionable. The opinion of the best informed men

seems to be that wheat should gradually pass to the

less valuable areas everywhere, making room for the

higher producing crops on land that bears high rent.

About all it requires as to soil is fair fertility and tilth.

It grows on sands, loams, clays, and silts, avoiding the

muck soils, which are too rich in organic matter. Deep,

uniform loams, however, generally give the best yields

where there is about twenty-five inches of rainfall. Good

fields of wheat are shown in Figs. 48, 49, and 50.

Hard and soft spring, hard and soft winter, and white

Wheat 175

wheats have adapted themselves to climatic conditions.

These variations illustrate only a few of the attempts of

the crop to suit more rigorous climates. Strains are

continually becoming adapted to drier or to colder dis-

tricts, where they were not successfully grown before. It

is because of this widely increasing variation coupled with

its manifold uses, that wheat has become such a general

crop.

183. Preparation of seed-bed. — The preparation of

land for planting differs with the region. The chief

difference is in amount of seed and time of sowing; the

methods of cultivation are primarily the same.

In general, the methods include plowing in the autumn

or late summer as soon after the crop is taken off as pos-

sible ; leaving the land rough over winter so as to prevent

run-off of rain or melting snow and to permit frost to break

clods or sod into finer particles; and harrowing in the

eariy spring to prevent loss of moisture by evaporation

and to keep down weeds. Fall-plowing ought to be as

deep as the machinery and the horses or other power at

the farmer's command will permit. Increased depth

of plowing makes a better home for the plant and stores

a greater quantity of moisture. In regions where spring

planting is practiced, deep fall-plowing is still valuable,

but in most cases the grain is not sown until it becomes

warm the next spring.

184. Seed and seeding. ВЂ” Farmers had better use

seed that is adapted to their system of farming. The

stubble ought to be turned under as eariy as possible

after harvest. Sometimes the land should lie through

the winter without harrowing. If farmers disk it, and

harrow after every rain that crusts the land or starts

weeds, they have a loose, moist seed-bed free from weeds

when planting time comes.

The Principlea of Agronomy

The grain ought to be

screened to remove weed

seed, rubbish, and

shrunken kernels. Large,

plump kernels give bet-

ter yields than small or

shrunken ones, because

of the better start they

give the young plants.

But more than screening

is necessary. For smut,

the grain should be

treated with formalde-

hyde, one pint to fifty

gallons of water, or with

blue vitriol (copper sul-

fate), one pound to five

gallons of water. A good

way is to dip a bag of

wheat into a solution

contained in a half barrel.

About ten minutes is re-

quired to wet all the

grain. In the meantime,

another sackful might be

screened and filled to

economize time.

From three to six

pecks of seed have given

the best crops where no

irrigation is practiced,

while under irrigation

four to eight pecks are

used. For spring-plant-

178 The Principles of Agronomy

lug, earliness is essential. Fall-plowing makes possible

earlier seeding, since disking is then all that is necessary

before planting. During growth about all that can be

done is to harrow.

186. Harvestiiig, — There is no month in the year

that is not a harvest season in some part of the earth.

The season varies in the United States from May in

Texas, to September in parts of the Northwest, Fall-

planted grain ripens early and spring-planted grain late

where the weather is cool or moist.

Methods differ as widely as seasons. In many parts

of the world, peasants still use the sickle or old-fashioned

Fia. 53. — ^ Thresher at work.

cradle, but modem harvesters are rapidly winning in all

progressive countries. In parts of western United States

the binder has given way to the header, which removes

the heads and elevates them into tight wagon-beds to be

hauled off and stacked until ready for threshing. The

header has been supplanted on some large farms by the

combined-harvester, a machine that cuts, threshes, and

sacks the grain in one operation.

Wheat 179

Binder-cut grain is shocked in the field where the straw

dries sufficiently to permit easy separation of the grain

from chaff. In some localities the wheat cut green is

ripened by the translocation of starch from the straw,

for which a long time in the shock is necessary. When

threshing time approaches the farmer hauls and stacks

the bundles, or he hauls directly to the thresher. When

grain is stacked, the bundles are usually placed with heads

in, so a^ to shed rain and resist the attack of fowls or

rodents.

186. Diseases. — Wheat is attacked by glume spot,

wheat scab, rust, leaf blight, powdery mildew, and loose

and closed smut. Of all these, however, rust and closed

smut are most serious.

187. Closed smut is a black,- thread-like fungus which

is spread by tiny, black spores that fly through the air

arid attach themselves to the wheat kernel. Sprouting

about the same time as wheat, the long, slender tube of

the smut enters the young plant and grows inside. It

follows up the green, growing plant, dying in the lower

part of the stem, as the straw hardens. At the time the

heads form, the smut enters the kernel and grows inside.

Infected kernels are like sound ones except they are dull

in color, light in weight, and hollow. They break easily

during threshing and when handled later, they scatter

spores which cling to the sound kernels. On account of

the resemblance in appearance to clean grain, the farmer

may not notice this smut, though he finds when threshing

a loss of from 10 to 40 per cent of the crop. This loss

can be prevented by treatment described (Par. 184). Care

should be taken that the formalin is 40 per cent for-

maldehyde. After the grain is treated, it is hung up

in bags or spread out on the barn floor to dry before

planting.

180 The Principles of Agronomy

188. Loose smut enters the plant at flowering time, and

lives inside of the kernel. The disease is less prevalent

than is that caused by closed smut. Treatment, however,

is more difficult, since the spores are inside the kernels

and cannot be reached by poisons. The only method is

one known as the hot-water treatment, which is extremely

hard to use successfully since, if the water be a few degrees

too warm, the germination quality of the wheat is injured

or destroyed. The grain is soaked for four hours in cold

water, since heat more readily penetrates wet grain.

To kill the smut, the wheat is immersed for ten minutes

in water maintained at 133^ F. The addition of the

cold wheat makes constant heating necessary. Because

of the difficulties, only small quantities of seed can be

treated. This is then sowed on a seed plat which will

yield clean seed for next season.

189. Rust is a fungous disease which attacks the stem

and leaf; that on the stem is the more serious. The

spores live over winter in the standing straw or even in

some other plant. In the spring, after germination, the

fungi attack the wheat at any time. The injury consists

in a failure of the grain to fill. Although considerable loss

results, about all that can be done is to choose rust-re-

sistant varieties, to rotate crops, to drain the land, and

to avoid over-irrigation.

190. Insects. — Hessian flies and chinch-bugs are the

worst of the insect enemies of wheat. The chinch-bug

attacks other crops, while the Hessian fly confines its work

mostly to wheat. The latter is a fly which lays its eggs

in the young plant. When the maggots hatch they rasp

the young tissue and drink the sap. The chinch-bug^ is

a beetle that eats the tender plants. They pass through

no true larval stage, but hatch continuously throughout

the early summer. Altogether these insects cause a loss

Wheat 181

of 10 per cent of the wheat crop. Spraying and catching

in plow furrows are advocated, but perhaps clean farming

and rotation are the better methods of control.

In so'me districts, wheat suffers considerable loss from

the wheat straw worm, which lays its eggs in the head and

stem of the plant. The wheat joint worm works in the

joints causing the grain to grow in bent positions, and

therefore to be missed by the header.

191. Weeds. — There are a few plants that have

become such nuisances to wheat that they have gained

reputations as pests. They steal plant-food and moisture,

shade and crowd out the crop, hinder harvest, and lower

the value of the grain by adding impurities. The weeds

most common in wheat-fields of the Mountain states

are the mustards, Russian thistle, sweet clover, and

June grass {Bromus tectorum). Chess or cheat is com-

mon in some parts of the East and middle West.

The mustards cause considerable trouble in some dis-

tricts. Since the seed lies for years in the ground, it

accumulates strength under single-cropping. Rotation

with intertilled crops is, therefore, an effective method of

combating it.

Russian thistle, a tumbleweed, and, for a long time,

almost master of the Nebraska wheat farms, is now spread

widely throughout the country. It scatters great num-

bers of seeds by rolling them before the wind. Rail-

roads introduce it into new localities; irrigation water

carries it to the fields ; sheep carry it in their wool ; and

soon the whole region is sown. It is especially trouble-

some on the dry-farm, but no matter where it exists it is

a pest to be reckoned with. For protection, it is covered

with sharp, spiny leaves.

Sweet clover and June grass are easily controlled by

thorough tillage, but they bother in haphazard farming,

182 The Principles of Agronomy

often increasing the labor and unpleasantness of harvest.

Careful seed selection and proper tillage will lessen in-

jury from chess.

192. Quality in wheat consists of the ability its flour

has to absorb large quantities of water thereby producing

larger leaves. This is because of the presence of a nitrog-

enous substance called gluten which, when wet, becomes

sticky. Generally, the more gluten present and the

more nearly it consists of 65 per cent gliadin and 35 per

cent glutenin, the lighter is the bread made from a flour.

Manifestly, however, stickiness cannot of itself cause

bread to rise. Hard wheats produce angular flour particles

rather than spherical or flat ones as does soft wheat.

The edges permit the sticky gluten to take hold of the

flour grains and to hold them more firmly together.

When the yeast added to the dough " works," it produces

carbon dioxide. Any substance in changing from a solid

or a liquid to a gas expands. As carbon dioxide is liber-

ated it needs more room; hence, it pushes the dough

aside, making it porous. Thus bread '' rises,'' that is, the

loaf increases in size but not in weight. The size and the

lightness of the loaf depend largely on the quality of the

wheat furnishing the flour.

Considerable skill is required to pick out the best wheat

from a number of samples. A clear, semi-transparent

amber color and a horny, brittle interior indicate high

percentage of protein. High nitrogen content gives any

cereal a greater food value, and it gives wheat flour more

desirable bread-making qualities. Shrunken kernels con-

tain much protein, but the gluten is poor. Maturity,

then, is also an essential characteristic of best quality