Soil Survey of Cass County, Indiana. 193 
Physical Properties.—In former years it was thought that the chem- 
ical analysis of a soil was of the most importance; but since the subject 
has been better understood, the physical side has gained in emphasis. 
A factor of prime importance to the agriculturist is the absorbing ca- 
pacity of a soil and its ability to retain and furnish moisture to the 
growing plant as needed. In fact the ability of a soil to furnish an 
adequate amount of water to the growing crop is of far more importance 
than its chemical ingredients. Pure sand holds water poorly, so that 
sand is ordinarily a dry soil. At the other extreme, clay holds moisture 
very tenaciously, so that a pure clay soil is soggy and apt to be very 
wet. A mixture of the two, forming a loam, is not subject to either 
objections and is an ideal soil. 
Liberation of Plant Food—Ground limestone and decaying organic 
matter are the principal materials which the farmer can utilize most 
profitably to bring about the liberation of plant food. The ground lime- 
stone corrects the acidity of the soil and thus encourages not only the 
nitrogen-gathering bacteria which live in the nodules found on the 
growing roots of the growing plants of clovers, cow peas, alfalfa and 
other leguminous plants, but also the nitrifying bacteria in the soil, 
which have the power to make into plant food the insoluble and un- 
available organic products. At the same time the products of this 
decomposition also make available the insoluble minerals found in the 
soil, such as the potassium and magnesium, as well as the insoluble lime- 
stones and phosphates, which can be applied by the agriculturist in a 
very low-priced form. 
One of the chief sources of loss of organic matter in the corn belt 
is the burning of the corn stalks. If the farmers would only realize 
the loss they incur they certainly would discontinue the practice. Prob- 
ably no form of organic matter acts to form good tilth better than the 
plowing under of corn stalks. It is true they decay slowly, but that 
only prolongs the desired conditions of the soil. The nitrogen in a ton 
of stalks is one and a half times that of a ton of manure, while a ton 
of dry stalks when ultimately incorporated with the soil is equal to four 
times that amount of average farm manure, but when they are burned 
the humus-making element and nitrogen are both gone and lost to 
the soil. 
Upland Soils.—The upland soils of Cass County are mapped in three 
series, namely: Clyde, Miami and Dunkirk types, and, in addition, the 
miscellaneous type known as Muck. These types are all due to a dif- 
ference in soil content and color and to surface conditions resulting from 
erosion. The Miami and Clyde series occur side by side, perhaps coming 
from a similar glacial till, but those areas having a better natural 
drainage and smaller amount of organic remains for humus become the 
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