1916] SHULL—SOILS 7 
more uniform behavior might be obtained under experimental con- 
ditions. The other seeds used were obtained from local seedsmen 
under the names given. 
The soils used in the major portion of the work will be charac- 
terized briefly. As a representative of heavy clay soil, the subsoil 
of the Oswego silt loam was chosen. Specimens of this subsoil were 
obtained from Riley County, Kansas, on an area about 2 miles 
west of Manhattan. The Oswego silt loam is a residual soil derived 
by weathering from underlying unbedded shales and sandstone, 
with the shales predominating. Its subsoil forms a hard, compact, 
brittle soil, with a gray to dark brown color. The average com- 
position as determined by mechanical analysis is given in table I. 
TABLE I 
SAND 
SILT Cray 
Coarse | Medium | Fine | Very Fine 
o.4 per cent | 0.5 per cent | 4.4 per cent | 3-2 per cent | 61.3 per cent | 30.4 per cent 
The moisture equivalent is 35.2 per cent, and the wilting 
coefficient is 19.1 per cent. The general details in regard to the 
Oswego silt loam and its subsoil may be obtained from the Eighth 
Report, Field Operations of the Bureau of Soils (11). 
As a contrast to the heavy silt clay, a fine quartz sand, the 
no. 2/0, which is manufactured by the Wausau Quartz Company 
from quartz rock, was chosen. This grade passes through a 124- 
mesh screen, and over a 147-mesh screen. The average diameter 
of the particles is very close to 0.10 mm. The chemical analysis 
given below shows it to be a very pure quartz sand. 
REPEC os io os ce cs 99.07 per cent 
Pe Es ike bs Paes ee ews 0.17 
PO, Os ie cee cena Q.52 
Hygroscopic Re eee ks ress es 0.06 
Bp Dy are car el eee 0.18 
100.00 
The moisture oo is 2.41 per cent and the wilting co- 
efficient 1.3 per cent. 
