Chapter 35

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 latitudes 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 latitudes 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, surpassing clover, but it is coarse, and its unattractive appearance has caused many farmers to condemn it without trial. Livestock eat it greedily, and it is one of our richest coarse 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 substitute 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 latitudes, 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 coarse 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 washing and paves the way for a sod of nutritious grasses.

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. Among the good cover crops is rye, both on account of its ability to grow under adverse conditions and because it produces a large amount of material for the soil. When seeded in the early fall, its roots fill the soil the following spring, and the tops furnish all the material that can be plowed down with safety. In northern latitudes it is the most dependable of all winter cover crops, making some growth in poorly prepared seed-beds and on thin land. The most value is obtained from early seedings, thus securing a good fall growth. Two bushels of seed are sufficient in good ground seeded ten weeks before winter begins, but two or three pecks should be added to this amount if the rye can be given only a few weeks of growth before frost locks up the soil. Rye can grow in warm spells of winter, and starts early in the spring. It uses up some available fertility that might otherwise be lost, and releases it when it rots in the ground.

When to plow Down.--If rye has made a good growth before spring, the roots run deeper than the plow goes, and holds the soil much like a grass sod. In such a case the plowing may be made early in the spring without regard to the rye, though organic matter increases rapidly day by day if the rye is permitted to grow. As a rule, it is safest to plow down before the plants are eighteen inches high. They dry land out rapidly, and any mass of matter in the bottom of the furrow interferes with the rise of water from the subsoil. When the land is wanted for oats or corn, a jointer should be used on the plow to insure burying all the crop.

Buckwheat.--An excellent crop for green-manuring is buckwheat. It has such unusual ability to grow in a poor soil that the farmer who makes free use of it as a grain crop never boasts of acreage planted, assuming that his land will not be highly regarded if known to be devoted chiefly to buckwheat. It does not withstand heat well, especially from period of blossoming to maturity, and therefore is restricted to cool latitudes. When grown for grain, it usually is not planted until July, and matures a crop in a shorter period than any other grain. It is sensitive to frost, but may be planted as soon as the ground is warm, and will give a good body of matter for plowing down within eight weeks. The root growth is not extensive, but the crop leaves naturally heavy soils more mellow, and it is an excellent cleansing crop for weed-infested fields. It makes a less heavy growth than rye, but can be used at a time of the year that rye would fail. There is time in a single season to grow two crops of buckwheat for green-manuring, turning the first crop down when the blossoms appear.

Oats.--When a fall growth is wanted for the soil, and it is preferred that the plants be dead in the spring, oats make a good catch crop.

Thin land which is wanted for seeding to wheat and grass in the fall, or for timothy and clover seeding in August, may use oats as a spring cover crop. A large amount of humus-making material may be gained by this means. The only danger lies in the effect upon soil moisture. The oat crop uses up the water freely in its growth, and when permitted to form heads before being plowed down, the mass of material in the bottom of the furrow does not rot quickly enough to induce the rise of water from the subsoil. The land should be plowed early enough to permit a solid seed-bed to be made.