20 
SOIL SURVEY OF JACKSON COUNTY 
and the surface soil in such places is somewhat deeper than the 
average. On some slopes the soil is somewhat darker in color 
and contains more organic matter than typical. "W hile a num¬ 
ber of such minor variations occur, this soil—as a whole is 
remarkably uniform.' 
Topography and drainage .—The Knox silt loam occupies a 
section of country which consists of a series of hills and ridges. 
The typical Knox silt loam is found occupying the tops of these 
hills and ridges where the surface is nearly level to gently roll¬ 
ing, and also the more gentle slopes where erosion is not a serious 
problem, and where all ordinary farm operations can be carried 
on without difficulty. On the steeper phase, the fields are sub¬ 
ject to erosion, and in some places deep ravines and gullies 
have been formed, causing considerable damage. Practically all 
of this phase can be cultivated, though some of it is sufficiently 
steep to make the operation of farm machinery difficult. Ero- 
i 
sion is the most serious problem to be considered in the cultiva¬ 
tion of the steep phase. On account of the uneven character of 
the surface, the natural drainage is good. The type is quite 
retentive of moisture, and suffers from drought only during long 
dry spells. 
The topography is such that drainage on this soil is almost 
always efficient, and only in isolated spots will the drainage 
ever need to be improved. 
* 
Origin .—The Knox silt loam in Jackson County lies directly 
over sandstone rock which underlies all the ridges and knolls 
at from two to ten feet beneath the surface. The surface soil is 
partly of loessial origin, having been deposited as fine dust by 
winds from the south and west in past geological ages. It is 
often noticeable that slopes which would be exposed to such 
winds are but thinly covered with the silt loam or the soil is 
sandy while in the lee of hills and ridges, the silt loam surface 
soil is often deeper than ordinary. This soil is also derived 
in part from shale associated with the sandstone. 
Most of this soil shows varying degrees of acidity; so much 
so that difficulty in getting alfalfa started will generally be 
experienced unless the soil is limed, heavily manured, and inocu¬ 
lated. 
Native vegetation .—The natural timber on this soil in Jackson 
County consisted mainly of wdiite, black and bur oaks, with 
