Reconnoissance soil survey of South Texas Page: 59 of 115
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RECONNOISSANCE SOIL SURVEY OF SOUTH TEXAS. 57
Owing to the sticky nature of this type when wet and the hard
condition when dry, cultivation is difficult, except when moisture
conditions are just right. If plowed when too moist it breaks up
into large clods or lumps which may require considerable work to
break down. New land, especially, is hard to plow and get in good
tilth. The soil, however, has a remarkable way of breaking up into
small granules and in a well-tilled field gives the fine, loose surface
so essential to conserve the moisture. This property of granulation
is doubtless due to the large amount of lime and humus present.
The following table gives the average results of mechanical analyses
of samples of the soil and subsoil of the Victoria clay:
Mechanical analyses of Victoria clay.
Number. Description. gravel ae Medium Fine Very fine Silt. Clay.
Per cent. Per cent. Per cent. Per cent. Per cent. Per cent. Per cent.
20324, 20795....... Soil......... 0.0 0.6 0.4 7.5 15.4 38.8 37.3
20325,20796....... Subsoil...... . 2 .3 7.0 15.9 34.1 42.5
The following samples contained more than one-half of 1 per cent of calcium carbonate (CaCOs): No.
20795, 2.38 per cent; No. 20796, 3.74 per cent.
Origin.-The Victoria clay has been derived through the general
processes of soil formation from the underlying calcareous clay of
Pleistocene age. The level topography, heavy texture, and calcareous
nature were all favorable to the formation and accumulation
of humus, which has given to it the characteristics of the typical
black prairie soils.
Location.-The type is found over a large part of San Patricio
County and also that part of Nueces County situated northeast of
Kmngsville and Alice. It occurs here in large connected areas,
covering a very large percentage of those two counties.
Topography.-The topography is level, and, where timber does
not obstruct the view, presents the characteristic level features of
the Gulf coast prairies. Very gentle undulations occur, but these
are often so slight as hardly to be detected with the eye. In a
region of greater rainfall the slope would not be sufficient to give
Proper drainage and would result in a swampy or marshy condition,
but in this region the level surface is an advantage, as the water
does not run off rapidly after heavy rains, but remains and is absorbed
by the soil, where it can be held by mulching for the use of crops.
A few drainage channels run through the type, but these are shallow
and carry water only after heavy rains.
Native vegetation.-The section mapped as Victoria clay was at
one time an open prairie covered with native grasses. During recent
years, or since the cessation of prairie fires, a large proportion has
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Soil map, reconnoissance survey, South Texas sheet (Map)
Map displays soil types along with arroyos, lakes, rivers, swamps, counties, towns, roads, railroads, and ranches. Includes legend and soil profiles.
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Coffey, George Nelson. Reconnoissance soil survey of South Texas, book, June 16, 1910; Washington D.C.. (https://texashistory.unt.edu/ark:/67531/metapth19753/m1/59/: accessed April 19, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu; crediting UNT Libraries Government Documents Department.