Crops and Methods for Soil Improvement Part 5

The trailing habit is affected by the soil, the bunch varieties tending to trail when grown on fertile land. When the crop is wanted for seed, the peas that do not trail heavily will prove more satisfactory. The selection of variety is a matter of lat.i.tude and purpose, exactly as it is with corn.

Fertilizing Value.--A heavy growth of the cowpea is worth as much to the soil as a good crop of red clover. When the equivalent of two tons of hay is produced, the roots and vines contain nearly as much plant-food as the roots and first crop of medium red clover that makes two tons of hay. Some a.n.a.lyses show a higher percentage of protein in cowpea hay than in clover hay, and the experience of many stockmen indicates that such is the case. The roots and stubble have somewhat less fertilizing power than in the case of the clover, and all thin soils should have the entire plant, or the manure from the hay, saved without loss.

Comparison is made on the basis of equal adaptability of soil and climate to clover and the cowpea. Going southward, the cowpea has the advantage, and northward the clover gains. It is in the overlapping belt that both should be freely used. The cowpea has distinct advantage over the clover in its ability to supply nitrogen and organic matter within a few months, and in its adaptation to very poor soils where clover would not make much growth. As a catch crop it has great value.

Affecting Physical Condition.--The cowpea has marked influence upon the physical condition of heavy soils, even when the vines are not plowed down. This is due in some degree to the roots, and probably more to the mulching effect of the vines during their growth. Heavy soils are made much more mellow by the cowpea, and when the crop is removed for hay, the stubble-land is easily prepared for a seeding to gra.s.s or small grain. When the growth is plowed down, the soil may be made too loose for seeding to small grain, but is put into prime condition for a tilled crop.

Planting.--The land should be fitted as it is for corn. Light, sandy soils require little preparation, and too often the seeding is made in a woefully careless manner, the chief dependence being placed upon sufficiently deep covering to insure germination. The ground should be fitted as well as it is for a cash crop, being made fine and smooth. A grain drill makes the seeding in a satisfactory manner, and the seed may be drilled solid or in rows for cultivation. When the crop is grown as a fertilizer or for hay, solid drilling is good, and about five pecks of seed gives a good stand of plants if peas are sound. Much cowpea seed is low in germination power, and the buyer should exercise caution. When a seed crop is wanted, two to three pecks of seed per acre, placed in drills 28 to 32 inches apart, make an excellent seeding, as cultivation can be given. The amount of seed varies with the variety. In northern lat.i.tudes a warm soil is to be desired, and cultivation gives better results when a seeding to wheat will be made on the pea-stubble.

There is evidence that the cowpea can make a heavy growth in soils too deficient in lime for red clover, and it gained its first prominence in southern Ohio on land that was failing to grow clover. It is the plant of adversity as well as prosperity, adding rich organic matter to thin soils, but making its full returns under better conditions. Lime applications on acid soils give increase in yields. Its one absolute requirement is heat, and in a cold summer its northern limit is markedly depressed.

Inoculation.--The inoculation of the soil with cowpea bacteria is necessary to best results in most regions new to the plant.

Self-inoculation is quicker in the cowpea than in alfalfa because the vines carry some soil on them, and thus the dust in the seed crop may be rich in bacteria. However, most new seedings of the cowpea do not show a large number of nodules on the plant roots, and inoculation pays. In some cases it makes the difference between failure and success. Two hundred pounds of soil from an old field should be well harrowed into each acre of land when preparing for a cowpea seeding in a new region. The soils of the southern states contain the bacteria just as the states in the clover belt are supplied with clover bacteria.

Fertilizers.--The light soils of Maryland, New Jersey, and the southern states are not naturally rich in phosphoric acid or potash. The cowpea can draw its nitrogen from the air, but on all thin land it pays to use 200 to 300 pounds of acid phosphate and 50 pounds of muriate of potash per acre for this crop which should have a luxuriant growth for the soil's benefit. Such use of fertilizers is more profitable than their use on the crop which follows.

Harvesting with Livestock.--When the cowpea is made into hay, there is always danger that the most of the plant-food contained in it never will get back to the soil on account of a careless handling of the manure. The practice of pasturing with cows and hogs is excellent. The feed is rich, and the manure is left on the ground. There is a saving of labor.

If the full fertilizing value is wanted for the soil, the crop should be plowed down. The trailing varieties form a tangled ma.s.s that cannot be handled by an ordinary breaking-plow, but a stalk-cutter, run in the direction the plow will follow, makes plowing possible. Pasturing with cattle and hogs sufficiently to reduce the growth so that a plow can be used is good practice.

The Cowpea for Hay.--The hay is one of our most palatable feeding-stuffs. Livestock may reject it the first time it is put into the manger, but a taste for it is quickly acquired, and soon it is eaten greedily. The high content of protein makes it exceptionally valuable for young animals and milk cows, and the manure contains a high percentage of nitrogen. The difficulty in making the hay is a drawback, but this is over-rated. While rain discolors the vines and makes them unattractive in appearance, the hay remains more palatable and nutritious than good timothy, if the leaves are not lost in curing.

When the first pods turn yellow, the crop should be harvested. The vines can be left in the swath until the top leaves begin to burn and then be put into windrows with a sulky hay-rake. The windrows should be small, the rake merely serving to invert half the vines upon the other half, bringing new surface to the sun. After another day of curing, the windrows should be broken up into bunches no larger than can be pitched upon the wagon by a workman, thus saving the trouble of disentangling the vines. If rain comes, the bunches should be inverted the following day. In dry, hot weather the curing proceeds rapidly, while in cooler lat.i.tudes or cloudy weather the curing may require a week. The chief point is to prevent undue exposure of the leaves to the sun, and this is accomplished by the turning. The hay will mold in the mow if not thoroughly well cured, unless placed in a large body in a deep, close mow that excludes the air. Some farmers use the latter method successfully, but the experimenter with the cowpea usually will fail, and should prefer thorough field curing, at the risk of some damage from rain and sun. The leaves are the most nutritious part of the plant, excepting the seed.

As a Catch Crop.--A leading use of the cowpea is that of a catch crop, either between other crops or in a growing crop, such as corn. Early maturing varieties can be brought in between main crops of the rotation in warm lat.i.tudes. The growth prevents the leaching of plant-food, shades the ground, adds nitrogen to the soil, smothers weeds, and produces material that is valuable as feed for livestock or an addition of organic matter to the soil. When the time that can be devoted to the crop is short, an early variety should be selected because its vines are far more valuable to the soil than an equal volume of a rank-growing variety that is not near maturity.

[Ill.u.s.tration: The cowpea seeded at the last cultivation of corn in the Great Kanawha Valley, W. Va.]

If this legume were used whenever opportunity afforded along the southern border of our northern states, and throughout the south, the faded color of soils, resulting from leaching rains, would be replaced by the darker colors that mark the presence of rich organic matter. It is one of nature's best allies in the maintenance of soil fertility.

CHAPTER XI

OTHER LEGUMES AND CEREAL CATCH CROPS

The Soybean.--The soybean is gaining a place among the valuable legumes of the United States, and the acreage is increasing as its merits become known to all. Its northern limits of profitable production are much farther north than those of the cowpea, and approach those of corn. In the south it is gaining friends. Some of the advantages of the soybean over the cowpea, as found by the Tennessee station, may be stated as follows:

1. Greater seed production in case of fertile soils.

2. Less sensitiveness to cold in spring and fall.

3. Greater feeding value of the seed.

On the other hand, a stand of cowpea plants is surer in the case of soils that crust, and germination runs higher. Its climbing habit makes it better suited for growing with corn for forage. A less amount of leaves is lost in curing.

Fertility Value.--There are so many varieties of the soybean and the cowpea, and adaptation to soil and climate varies so widely, that a fair comparison is difficult to make. In cool lat.i.tudes the soybean is recognized as distinctly more profitable, making larger yields of vines and of seed. Where adaptation is equal, the cowpea makes a slightly larger growth of vines for hay, but the soybean gives a much richer lot of seed for use as grain.

When soil fertility is the chief consideration, the adaptation of climate and soil should decide our choice between these two legumes.

There is no serious difference where conditions for each are equally good. In cool lat.i.tudes the soybean should be chosen. In the Ohio Valley it is usually to be preferred. The greater part of the organic matter and the plant-food is stored in the vines and seed.

Feeding Value.--The soybean makes a rich hay, surpa.s.sing clover, but it is coa.r.s.e, and its unattractive appearance has caused many farmers to condemn it without trial. Livestock eat it greedily, and it is one of our richest coa.r.s.e feeds. The curing is more difficult than in the case of the cowpea because the leaves drop early, and the plants must be harvested before they approach maturity.

Probably the large yield of rich seed is the most important feature of the soybean crop. A ton of the seed contains as much protein as a ton of old-process oil meal, and three fourths as much as a ton of cottonseed meal. A good crop of the soybean will yield 18 to 20 bushels of seed, and as the nitrogen may be obtained chiefly from the air, the protein from this crop will come to be a leading subst.i.tute for purchased protein feeds.

Varieties.--There are many varieties of the soybean, and their characteristics are modified by climatic conditions. Each region will find the varieties best suited to its purposes by tests. When hay is wanted, the variety should have fine stems and a leafy habit of growth.

It may not be a good producer of seed, or able to hold the seed unshattered. The harvesting should be done when some lower leaves turn brown and before the pods are half filled. This stage of maturity should be reached early enough in the fall to insure some hot days for making the hay, and to permit harvesting in time for seeding to wheat.

The preparation for wheat is made with the harrow and roller or plank drag.

When the soybean is grown for seed, the variety should hold the peas without undue shattering, and an erect grower is more easily handled without loss of the crop. Varieties for regions will vary, as do varieties of corn, according to climate.

The Planting.--Early varieties of the soybean in the south can be planted as late as mid-summer, but farther north a profitable crop requires nearly all of the summer heat. The planting may be made soon after the usual time of planting corn, or whenever the ground has become warm. The preparation of the soil should be more thorough than that often given the cowpea. Solid drilling of five pecks of seed per acre is satisfactory when the crop is for fertilizing purposes only, and gives an excellent hay on land free of weeds. When the crop is wanted for hay, however, wheat usually will follow, and it is much better to plant in rows and to give two or three cultivations so that the ground may be easily prepared for the wheat.

A seed crop should be grown in rows. Three pecks of seed in rows 28 inches apart is the usual amount.

The soybean does not come up through a crusted surface as well as most other plants, and planting should not be made immediately before a rain. The plants are tender and easily injured by use of a weeder.

The fertilizer requirement is like that of the cowpea. An application of 200 pounds of acid phosphate per acre should be given, and the addition of 50 pounds of muriate of potash often pays.

Harvesting.--The soybean is not an easy crop to handle without loss.

When grown for seed, the tendency of the pods to split and to drop the seed compels early cutting, and that makes curing more difficult. The mower is the only practical harvester on most farms, and the swath must be turned out of the way of the horses to save tramping. A side-delivery attachment can do the work. This is the best practice when cut for hay. When used for mixing with corn in a silo, the self-binder is satisfactory. The hay and seed crop must have thorough field-curing in windrow and bunches, and the harvest comes in a season when cold rains may prevail. This disadvantage of one of our most valuable crops is to be taken into account, but it will not prevent rapid increase in acreage as the merit of the soybean becomes known.

The Canada Pea.--Among field peas there are many varieties, but the one chiefly grown in the United States under the general name of the Canada pea is the Golden Vine. It makes a green forage or hay that is rich in protein. Usually it is grown with oats, giving a hay nearly as nutritious as that of clover. The crop is adapted to cold lat.i.tudes, and the planting should be made as early in the spring as possible.

Fall-plowing of the land is to be advised on this account. A good method of seeding is to drill in six pecks of the pea seed to a depth of four inches, and then to drill in six pecks of oats.

The crop should be cut for hay when the oats are in the milk stage. At this time the peas are forming pods. The hay is not easily made, but is specially valuable for dairy cows.

There is no profitable place for the Canada pea in crop-rotations farther south than the true oat-crop belt, except as a green-forage crop. The soybean and red clover have greater usefulness in the center of the corn belt.

Vetch.--A variety of vetch known as winter, sand, or hairy vetch is coming into great usefulness as a catch crop. It is a winter annual, and being a legume, it has special value as a fertilizing crop. It is more hardy than crimson clover, and is grown as far north as winter wheat. The seeding is made in August in the north, and when grown for hay or seed, it needs rye or wheat to hold it up. Rye and vetch make a rich and early green forage crop, and the proportion in which they are seeded varies widely in practice. Six pecks of rye and 15 pounds of vetch make an excellent seeding per acre.

When grown for seed, one to two pecks of rye and 20 to 30 pounds of vetch may be used. The rye can be fairly well separated from the vetch by use of a fanning-mill or an endless belt of felt so inclined that the round vetch seed will roll down, while the rye sticks to the felt and is carried over.

Vetch is excellent as a fertilizing crop, adding a great amount of nitrogen to the soil when plowed down in May. If the seed were cheap, its use would become much more common. Thirty pounds should be used when seeding alone after summer crops or in corn. Farmers should produce the seed for their farms, and use it freely. When sown for seed, September first is a good date for the north. The seed matures in June.

As vetch matures with wheat, it may easily become a weed on farms devoted largely to small grain, but it is not to be feared where tilled crops and sods are the chief consideration. Inoculation is needed for best results, as in the case with other legumes new to a region.

Sweet Clover.--Much interest has been aroused within recent years in sweet clover, a legume that formerly was regarded as a more or less pernicious weed. Its friends regard it as a promising forage crop, but too little is definitely known to permit its advocacy here except as a soil-builder in the case of poor land that is not too deficient in lime to permit good growth. Experiments have shown that a taste for this bitter plant can be acquired by livestock, and it is nearly as nutritious as alfalfa when cut before it becomes coa.r.s.e and woody. It is a strong grower, sending its roots well down into the subsoil, and its great ability to secure nitrogen from the air enables it to make a very heavy growth of top. The yield in forage usually exceeds that of the clovers.

Its most peculiar characteristic is its ability to thrive in a poor, compact soil that contains little humus. It may be seen in thrifty condition on roadsides and in waste places that seemingly would not support other plants. Laying aside all consideration of its possibilities as a forage crop, it will come into greater popularity as a soil-builder on thin land. It is found usually on land of limestone formation, and shares with other legumes a liking for lime, but it has been grown successfully in regions that are known to have a lime deficiency.

There are two biennial varieties and one annual. The biennial having white blossoms is the one most commonly seen, but the smaller variety with yellow blossoms is more leafy and palatable. The larger variety is the better fertilizer.

The seed does not germinate readily, and 20 to 30 pounds is used per acre. The soil should be compact, and the seeding can be made in the spring with a cover crop, or in August by itself. Inoculation is necessary if the right bacteria are not present. Soil from an alfalfa field will serve for inoculation.

An effort should be made to grow sweet clover on all infertile hillsides that are lying bare. It stops was.h.i.+ng and paves the way for a sod of nutritious gra.s.ses.

Rye as a Cover Crop.--As has been stated elsewhere, the plant that stores nitrogen in its organic matter is most desirable, but the greater part of the soil's stock of humus did not come through legumes.