Grasses for Hay and Pasture

by M. A. HEIN

THERE ARE about six thousand different species of grass. They are, in the words of Judge Ingalls, the benediction of nature. They are also, as 20 years of drought, insect plagues, and war have demonstrated, of unmeasured value to agriculture and the Nation's economic life.

Grass has gained this new importance and versatility from programs of breeding, introduction, and adaptation that a number of men and institutions have carried on. In 1928 the Department of Agriculture started an intensive effort to improve grass and pastures to help control the corn borer. Beginning in 1933, the Soil Conservation Service and the Agricultural Adjustment Administration developed projects to save soil and stabilize farming by planting more land to hay and forage crops. During the years of drought, special attention was given to the search for hardy, drought-resistant plants of all kinds from foreign sources. We also stressed improvement of grasses by breeding the materials at hand.

Through the Division of Plant Exploration and Introduction we have been extremely fortunate in obtaining a large number of grasses to supplement our native and naturally introduced grasses. Conspicuous examples of this are Sudan grass and crested wheatgrass. Their value and widespread use are already well understood. Many others, brought in more recently, are proving their worth. I give a few examples to illustrate the use that can be made of them under our wide variety of soil and climatic conditions.

Pangola grass (Digitaria decumbens), introduced from South Africa in 1936, has shown promise in Florida. It was first released to farmers by the Florida Agricultural Experiment Station in 1942. It produces little viable seed and must be propagated vegetatively. It is a rapid-growing perennial, withstands grazing well, and is quite drought-resistant, but it is sensitive to frost and has not proved winter hardy north of Florida. More information, however, is needed on its range of adaptation.

Russian wild-rye (Elymus junceus) was first introduced in 1928 from the Soviet Union. It has about the same range of adaptation as crested wheatgrass and can best be compared with it. Failure to produce seed consistently has been its principal weakness and has limited its use to the Northern Great Plains, where it is best adapted.

Intermediate wheatgrass (Agropyron intermedium), another introduction from Russia, has shown considerable promise in the Northern Great Plains and the Intermountain region. The original introduction was a mixture of two species, A. intermedium and A. trichophorum. As a result, it has shown considerable variation. It is less drought-resistant than crested wheatgrass and more drought-resistant than bromegrass. The South Dakota Agricultural Experiment Station has increased it under the name of Ree wheatgrass.

Turkestan bluestem. (Andropogon ischaemum) and Caucasian blue-stem (A. intermedius caucasius), also introductions from Russia, show promise in the Southern Great Plains. They are vigorous, high-producing plants with fair production of seed. Both are finer stemmed and of better texture than our native bluestems.

Three lovegrasses, weeping lovegrass (Eragrostis curvula), Lehmann's lovegrass (E. lehmanniana), and Boer lovegrass (E. chloromelas), all introductions from Africa, have proved to be valuable. Weeping love-grass, well adapted to the Southern Great Plains, has been widely distributed, and is the most winter-hardy of the three. Lehmann and Boer lovegrass are promising in semiarid parts of the Southwest, southern New Mexico, and Arizona.

From these examples of introductions and their development it is apparent that we cannot depend entirely on introductions to meet our changing agricultural needs. Plant breeding is essential in developing species and strains for a grass and pasture program adapted to the conditions where it is to be grown.

Objectives in the improvement program vary within different grasses and regions and include one or more of the following: Resistance to diseases, insects, drought, heat, or cold; seed production; seasonal growth; compatibility; recovery value after grazing or mowing; palatability and nutritive value; aggressiveness; and high yield. It must be recognized that the improved characters desired in any particular grass will depend largely upon the climate of the region in which it is to be grown and the purpose for which it is to be used.

Almost 70 different species of grass are included in some kind of selection, improvement, or breeding program conducted by the Department alone or by the Department in cooperation with States or State experiment stations. This program also includes increasing field-selected material of native and introduced species for conservation and soil-improvement purposes. These lines have not necessarily been selected for type, but rather on the basis of regional adaptation. That is an important factor, because even in field-selected material that has been growing for many years under a particular environment there has been some natural selection by processes of the survival of the fittest.

Some examples of different species adapted to broad climatic regions of the United States will illustrate the advantages of improved varieties.