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 UNITED STATES DEPARTMENT OF AGRICULTURE, 
 •I 
 
 DEPARTMENT CIRCULAR 43. 
 
 Contribution from the Bureau of Plant Industry, 
 (Forage-Crop Investigations). 
 
 WM. A. TAYLOR, Chief. 
 
 REDTOP {Agrostis alba). 
 
 Eedtop is the only grass of much prominence as a hay plant among 
 the many grasses belonging to the genus Agrostis. It was early 
 introduced into the American Colonies. This grass has been known 
 under many common names, such as whitetop, fiorin, white bent, and 
 herd's grass. As these names belong more properly to other grasses, 
 all of them should be dropped and the term redtop, by which it is 
 most commonly laiown, used exclusively. It is a perennial grass, 
 Avith a creeping habit of growth, which makes a coarse, loose turf. 
 It matures at about the same time as timothy. The leaves are about 
 one-fourth of an inch wide, and the stems small and wiry. The hay 
 is inclined to be tough and is generally unpopular on the market. 
 
 VALUE. 
 
 No grass will grow under a greater variety of conditions than red- 
 top. It is the best wet-land grass among the tame species. It will 
 grow on soils so deficient in lime that most other grasses fail. It is 
 strongly drought resistant and is often used for holding banks to 
 prevent erosion. Eedtop is second only to bluegrass as a pasture 
 plant in the northeastern part of the country. It is a vigorous grower 
 and will serve in a short time where a turf is desired. It will thrive 
 from Canada to the Gulf of Mexico and from New York to Cali- 
 fornia. Though often used in lawn mixtures, its use by itself for 
 that purpose is not to be recommended. The turf is unsightly after 
 the first year, and it tends to keep out more desirable species. It will 
 add to the yield of a timothy and clover hay crop, but is considered 
 objectionable by buyers of market hay. 
 
 USES. 
 
 The chief uses of this grass are (1) as a wet-land or sour-land hay 
 crop; (2) as a part of pasture mixtures under himiid conditions, 
 
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 especially on soils other than limestone; (3) as a soil binder; and 
 (4) as an ingredient in all hay mixtures which are to be fed at home. 
 It may be used for lawn purposes, especially on poor soils when 
 the finer species of Agrostis can not be obtained. It is not a com- 
 petitor of bluegrass for lawns, as the latter should be used on fertile 
 limestone soils. Kedtop is a valuable grass when used for the pur- 
 poses mentioned. 
 
 SEED. 
 
 Most of the seed of redtop is produced in southern Illinois. The 
 seed is smaller than that of any other commercial grass, and for that 
 reason should be comparatively free from impurities, as it is easily 
 separated from other seeds by screening. It is sold in two grades, 
 known as " chaffy " and " recleaned." The latter should be pur- 
 chased, as it is more economical and there is less danger of its contain- 
 ing noxious weed seeds. Redtop seed weighs about 14 pounds to 
 the bushel in the chaff, while the recleaned seed should weigh about 
 36 pounds. 
 
 SOILS AND CLIMATE. 
 
 Redtop is not only tolerant of a sour soil, but seems to prefer a 
 soil deficient in lime. It grows to perfection in the part of southern 
 IJlinois known locally as " Egypt," where many soils are very " sour " 
 and poorly drained, with impervious hardpan subsoils. In New 
 England it is the principal hay plant that is seeded, but it is fre- 
 quently crowded out of meadows by quack-grass and Rhode Island 
 bent. As previously stated, it is not particular in regard to climatic 
 conditions, but thrives best with an abundance of moisture. Lands 
 which are too wet for redtop are unsuited for nearly all other tame 
 
 grasses. 
 
 CULTURE. 
 
 On account of its small seed redtop should have a fine, mellow seed 
 bed, and care should be taken to prevent covering it too deeply in 
 the soil. It may be seeded either in early spring or late summer. 
 When seeded alone 10 pounds of good seed to the acre will insure a 
 stand. From 4 to 5 pounds are sufficient when used with other 
 grasses for hay, and 2 to 3 pounds are enough to use in pasture mix- 
 tures, as it spreads quite readily under favorable conditions. 
 
 Lyman Carrier, 
 
 Agronomist. 
 
 Washington, D. C, May 31, 1919. 
 
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 MENff PRINTING OFFICE : 1919 
 
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