New Legumes for the South

by ROLAND McKEE

IT IS JUST as big an accomplishment to introduce a new and suitable legume into any area as it is to build a highway or perfect a new kind of airplane. The same degree, if not type, of knowledge and skill is needed------basic information about weather and soil, the uses to which the project is to be put, fundamental natural and physical laws and sciences, and adaptation. Adaptation means suitability; in the case of plants, it means suitability to the usual farm operations of a locality, its rainfall, fertility, length of season, temperatures, incidence of diseases, topography, and market requirements. It would not do to plant a crimson clover adapted to Carroll County, Iowa, in Carroll County, Ga., and expect it to do equally well in both places.

In recent years several new legumes have been added to southern agriculture. They fit into places and uses for which other legumes were not available. Some of them are new varieties of familiar crops—lespedeza, field peas, crimson clover, vetch, crotalaria, and lupines. Others, hairy indigo and big trefoil, are new to southern farmers. Lespedeza is perhaps the, most important.

Korean lespedeza now covers millions of acres in the United States, but it was unknown to agriculture only 25 years ago. But despite its newness, selection of improved strains has been possible, and two varieties of special value have been perfected. One, known as Early Korean, is recognized as superior for northern parts of the lespedeza area, and has extended the use of the crop farther north. It was first selected 15 years ago, but its increase and extension of use are a current development. The other, even more recent, is a high-yielding, late-maturing strain that has been named Climax. Climax was released in 1946 after experimental tests so the amount of seed could be increased. It is adapted to southern sections and will help extend the use of Korean lespedeza in the South. Furthermore, the habit Climax has of maturing late will extend the grazing season and give larger hay yields.

Both strains have outyielded unselected commercial lespedeza in the region of their adaptation. The Early Korean variety not only yields well, but can be grown farther north than commercial Korean. It also makes earlier growth and thus affords earlier grazing. Climax, on the other hand, produces heavy hay yields, makes late growth, and affords later pasturing than other Korean varieties.

Austrian Winter fieldpeas are used extensively for soil improvement, but diseases have greatly reduced their value. After several years of breeding work and study of these diseases, investigators have evolved varieties with partial resistance to disease. Seed of them is now being increased for more general use. Unfortunately, fieldpeas do not develop seed well in the South, and it is necessary to depend on other regions for seed. In developing disease-resistant strains, hybrid seed selected in the South is sent to other areas for increase and commercial production.

With any legume, old or new, it is desirable or essential that seed be available at low cost. If a crop must be seeded every year, the cost of seed and preparation of land must be given consideration. If a crop can be volunteered from seed produced on the land by a preceding crop, the cost of seeding is cut way down—an especially desirable factor in the case of soil-improving crops. Spotted bur-clover, crotalaria, and roughpea are three such crops that can be handled in this way. Spotted bur-clover has been grown a number of years, but the use of crotalaria and roughpea is recent. Of interest in this connection is a variety of crimson clover that has recently been developed, Dixie crimson clover.

Another winter legume that produces seed well in the South and can be readily volunteered is big-flower vetch. It has proved its worth in experimental tests, and growers have made commercial plantings of it. When once established, it persists without further cost for seed, and because it makes good winter growth it is a promising winter cover crop for soil improvement. Like most commercial vetches, it is of European origin. When the plant is ripe the seed shatters easily—a deterrent to seed increase. High cost of seed, however, is of minor importance when one considers that when vetch is once established it will last 5 years or more.

Although crotalaria has been grown widely since 1930, it is a comparatively new crop. It is of special interest for soil improvement because it makes good growth on poor, sandy soils and does not harbor nematodes.

For that reason, crotalaria helps rid the land of this pest, and can be used to advantage in rotation with crops susceptible to nematode damage. Crotalaria also keeps down weed plants that are hosts to nematodes. In orchards, susceptible trees can be protected from infection by keeping a covering of crotalaria on the land during the season when weeds or other susceptible plants might be growing. The full value of crotalaria for use in reducing nematode damage has not been fully appreciated, but with extended use its value for the purpose will be further demonstrated.