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parently similar conditions of soil, soil moisture, aspect of land, etc., and a separation even in the broadest sense would not be practical. The purpose in mind has been more to designate the conditions favorable for their best natural reproduction and develop. ment, than to separate them into localized areas.

PHYSICAL CHARACTERISTICS OF THE SOIL.

SOIL INGREDIENTS.

1. Sand.
2. Silt.
3. Clay.
4. Humus.

A mixture of these four ingredients makes a loam which is the most valuable of all soils.

CHARACTER OF INGREDIENTS.

Sand-Grains of quartz large enough to be seen with the naked

eye.

Clay_Very fine particles of rocks such as silica, limestone, mica and feldspar.

Silt-Soil particles intermediate between clay and sand. It holds water well and is rich in plant food.

Humus-Mostly decayed vegetation.

LEADING TYPES OF SOILS.

Classed according to the predominating ingredients.

Sandy soils—Contains 80 per cent. of sand and less than 10 per cent. of clay.

Clayey soils—Soils consisting mainly of silt.
Humus soils-Soils in which decayed vegetation predominates.

Loam soils—Combinations of sand, silt, clay and humus, the sand predominating in sandy loams and clay in clayey loams.

PER CENT. OF INGREDIENTS IN VARIOUS SOILS.

Sandy loams—60 to 70 per cent. sand.
Light sandy loam--70 to 80 per cent. sand.
The other ingredients of these soils are clay, silt and humus.

Clay soils—60 per cent. or more of clay and silt. Clay soils being exactly the reverse of sandy soils.

Clay loams-30 to 40 per cent. clay, 25 to 30 per cent. sand.
Heavy clay loam–10 to 25 per cent. sand.
Loess soils-Fine silt or clay, containing 55 to 75 per cent. of

silt and 6 to 15 per cent. of..clay. Found over considerable areas in southern Indiana.

In selecting a soil for any purpose special attention must always be given to its physical conditions. S. W. Fletcher says, in his treatise on "Soils, How to Handle and Improve Them," that the cause of the unproductiveness of soils is due to the physical conditions and not to the chemical contents. The problem of soil fertility for any growing form depending, not so much upon the amount of plant food present in the soil, as upon its physical character.

A mechanical analysis of many of the dominant soil types could be given, but would do little to assist the ordinary observer in any undertaking with forest plantings. Also the varying conditions and widely differing types of soils found in Indiana, in addition to the fact that they are most confusingly and miscellaneously distributed over the State, makes it absolutely impossible, and to a degree impracticable, to do more in such a limited time, than consider general and predominating types.

“The soils of Indiana may be roughly classified into three great groups, viz., drift soils, residual soils and alluvial soils. The drift soils are found in the northern three-fourths of the State, are extremely varied in depth and character and are formed of a mass of heterogenous material which was brought to its present resting place by a great glacier or slowly moving sheet of ice, which thousands of years ago covered the area mentioned.

"The residual soils are found in the counties south of the southern limit of the glacier. They were formed, for the most part, in the place where they are now found, by the decay of the underlying limestone or sandstone rocks." (See Fig. 20.) “The variety of materials entering into their composition is therefore limited, and they are, for this reason, among the poorer soils of the State."

"The alluvial soils are those of the river and creek bottoms throughout the State. Gentle rains and earthborn torrents, little trickling rills and strong streams are ever at work tearing down the soils and underlying clays from every slope, and bearing them away to lower levels. The small water-formed trench of today next year becomes a chasm and ages hence a hollow, and the transported material is gradually deposited as alluvial soil over the socalled 'bottom-land' which are annually overflowed.

“The drift soils cover the northern and central portion of Indiana, derived, as they were, from various primary and igneous rocks in the far north, ground fine and thoroughly mixed as they were

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by the onward moving force of a mighty glacier, are usually rich in all the necessary constituents of plant food. Neither they nor the alluvial soils require a large annual outlay for fertilizers, as do the residual soils of southern Indiana, over which the drift of the glacial period did not extend.”_Blatchley, 21st Annual Report of the Department of Geology and Natural Resources, 1896, pages 21 and 22, State of Indiana.

The soils of the northern and central counties assigned for investigation came under the class of drift soils, while those of the southern came under residual soils. The alluvial soils being distributed to some extent over the entire State, are found in each of the three groups of counties. These counties being assigned in groups of threes, each group representing consecutively northern, central and southern conditions, the soils and other topographical features will only be discussed for the groups, and not for each separate county.

The northern group therefore, consisting of Marshall, Starke and Kosciusko, lies in the northern central part of the State. Data collected by the United States bureau of soils shows a fairly uniform distribution of rainfall throughout the year, with a maximum during the growing season. The temperature is characterized by sudden changes and by alternating freezes and thaws, during the winter and early spring. From a tree planting standpoint these are unfavorable conditions and many reports were received where young growths of catalpa and black walnut were killed or “frozen back" to such a degree that the season's growth was indeed slight. See Fig. 30, which is a planting of black walnut where numerous trees were killed by severe and rapid changes in the temperature, and by the cold winds which sweep across this part of the State during the winter months. Soil conditions also played a most important part in the success of this planting, but will be discussed later. Specific examples cannot be considered at this point, but must give place to a more general description of soil and surface conditions.

This northern group of counties, falling as it did directly in the path of the glacier, is covered to a great depth by drift deposits. No outcrop of stratified rock is seen, nor has it been reached by the deepest borings. The character of the surface materials though not widely differing, is found to vary to a considerable extent with the general topography of the land.

Generally speaking, a line running north and south through the center of Marshall County separates the sandy soils from the clay soils. What are known as 'clay soils,” to which the government has given the name, Marshall loam, is found principally east of this line. The “sandy soils” occur west of this central line and are of several distinct types. Three of the principal ones are, Marshall sandy loam, Miami sand and Marshall sand.

The topography of this group of counties is quite level, with small areas of rolling country along Yellow River and in the vicinity immediately surrounding the lakes. That part lying east of the central line above mentioned is comparatively level or gently rolling, with scattered groups of low hills. Westward from thi; line the land takes on a more rolling topography, until well into Starke County, where with many intervening depressions or slight valleys it gradually assumes a low level aspect, characteristic of the Kankakee region. The so-called bowlder clay is in this part found at greater depths, while the sand increases until finally the sand barrens” are reached. These barrens seem to be wind-blown deposits and frequently take on the characteristics of sand dunes. They are also found in many places to have the appearance of old beach lines. There are many basins and depressions over the entire area, but are more extensive east of the central line. The basins are generally known as marsh, and the soil found within them is ordinarily classified as muck. In many parts bowlders are scattered over the surface of the ground and consist chiefly of granite, gneiss and other metamorphic rocks. From records obtained from borings these rocks seem to be more abundant near the surface. This is a natural result and accounts only to a very slight degree for the different classes of soils found in this region.

As many as nine types of soils have been classified and described from this region. They range in texture from sand to clay loam and are thus seen to offer a wide diversity as to productivity. Of these nine types, the Marshall loam occupies by far the largest and most uniform areas. It is found chiefly east of the dividing line, but occurs west of it in small areas. This type of soil was originally covered with a heavy growth of black walnut, and is still locally known as the “black walnut land.” Even now an occasional small patch is seen where the original timber has been reserved, but these patches are rapidly disappearing and in a few years will be entirely removed.

The sandy soils, found west of the central dividing line, are comparatively shallow and of medium texture. In the depressions and low valleys the soil becomes more loamy, darker and extends to greater depths. These sand soils, of which there are three prin

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