8 BULLETIN 336, IT. S. DEPARTMENT OF AGBICULTTJEE. 



At Arlington also most of the field tests have been conducted on 

 twentieth-acre plats (16^ feet by 132 feet). During the earlier years 

 of the work tenth-acre plats (33 feet by 132 feet), and also a few 

 fortieth-acre plats (8| feet by 132 feet), were used. These plats also 

 lie in series running north and south, with 18-inch alleys between the 

 plats within the series. The series are separated by roadways 19-f 

 feet in width. 



TREATMENT AND CROPPING OF PLATS. 

 / 



The cereal experiments at Arlington Farm have been conducted 

 on land that is undergoing a system of soil renovation by the use of 

 green-manure crops, stable manure, commercial fertilizers, and lime. 

 Sufficient acreage has been available to allow the alternation of the 

 cereals, with other crops. By this method the mixing of varieties' 

 from volunteer plants is avoided, and there is opportunity to carry 

 out the general scheme of soil improvement. In general, the cereals 

 have followed crops of cowpeas or soy beans plowed under in late 

 August or early September. This is usually the third green-manure 

 crop to be plowed under during the 15 months that elapse between 

 the two grain crops, as the latter are always immediately followed as 

 well as preceded by cowpeas or soy beans with a crop of winter rye 

 between the two legume crops. 



In addition, a top-dressing of about 10 tons of stable manure per 

 acre is applied to the rye during the winter. At seeding time 200 

 pounds of acid phosphate, containing about 14 per cent of phos- 

 phoric acid, are applied. 



Immediately after plowing the plats are worked down with the 

 disk and acme harrows and allowed to remain until seeding time, 

 when a good seed bed is usually obtained by double disking and 

 harrowing. 



The seeding is done with an 8-foot single-disk drill. The disks 

 are 8 inches apart, with no chains or other leveling or compacting 

 device attached. After seeding, the plats receive no further treat- 

 ment, except that just prior to harvesting they are rogued in order 

 to keep the varieties as free as possible from mixtures. The har- 

 vesting is done with an ordinary grain binder. The bundles are 

 shocked, placing from 12 to 14 in a shock, and are allowed to stand 

 in the field until stored or thrashed. The grain in the shock usually 

 is protected from birds and the weather by canvas shock covers. 



The small-grain crops at College Park are included in a more or 

 less definite rotation, in which no hay or grass crop is used. The 

 scheme has been to grow corn two years, followed by wheat or other 

 small grains two years, with supplementary crops of crimson clover 

 and cowpeas for green-manuring purposes. 



Manure and commercial fertilizers also are used to maintain the 

 soil fertility. The former is used on the corn crop, while the latter 



