MANAGEMENT OF GENERAL FARMS IN OREGON. 3 
farming crop yields gradually declined. The average yield of wheat 
for the Willamette Valley during the early eighties was not far from 
17 bushels per acre. The United States Census report shows that the 
average yield of wheat for Benton, Clackamas, Lane, Linn, Marion, 
Multnomah, Polk, Washington, and Yamhill Counties for the year 
1880 was 14.9 bushels per acre. 
The practice of summer fallowing from one-fourth to one-third of 
the land each year and the production of wheat and oats to the 
exclusion of almost all other field crops has prevailed on the red hill 
or clay type of soil to the present time. On the silt loam or "val- 
ley" soil, on the other hand, radical changes in the type of farming 
have taken place. Clover and vetch were introduced during the 
eighties and early nineties, and the practice of summer fallowing 
has practically been abandoned on this type of soil. The influence 
of these leguminous crops on crop yields and the efficient management 
of these farms will be shown in the tables which follow. 
TYPES OF SOIL. 
The 212 farms which constitute the basis of this study are located 
on two distinct types of soil, Salem silt loam and Salem clay. l The 
Salem silt loam is locally known as "valley" or "prairie" soil. It 
occupies the level and gently rolling valley lands. The soil is a brown 
to black silt loam, 18 to 24 inches deep. The subsoil is a yellowish 
to red clay loam which becomes heavier with the depth. The Salem 
clay type is locally known as "red hill" soil. It occupies a series 
of ro ling hills on either side of the "valley" or silt loam soil. The 
Salem clay soil consists of 12 to 15 inches of red clay, which is under- 
lain by a clay of much the same color and texture as the surface 
soil. 
DEFINITIONS OF TERMS USED. 
Definitions of some of the terms used in this discussion may be 
found helpful in studying the tables which follow. 
Improved land. — The usable portion of the farm. It includes the 
tillable area and any portion of the farm that has been improved 
sufficiently to furnish fairly good pasturage. 
Rotation area. — That portion of the farm upon which field crops 
are changed about from year to year. It includes the areas in field 
crops, summer fallow, and pasture in rotation. It does not include 
the area in fruit and garden. 
Field-crop area. — That portion of the farm occupied by the field 
crops. 
i Salem silt loam and Salem clay are terms applied to these soils by the Bureau of Soils, U. S. Depart- 
ment of Agriculture, when making a soil survey in Marion and Polk Counties, 1903. 
