Soil representation on topographic map

Top-soil. Top layer of the earth's crust with depth of some meters is called ground. Top mellow layer of ground (with depth 1-1,5 meters) which is fertile is called soil. Ground is divided into rocky and mellow. Rocky ground is a monolith of firm rock (granites, basalts, sandstones). They are widely spread in mountains. Mellow ground is formed as a consequence of decay. It can be loose, medium and firm.

Types of soils

Main types of soils are formed as zones, which are situated from poles to equator under the influence of climate.

Tundra soils can be found in north regions with humid and cold climate. It is usually full of water, to a high degree waterlogged, at some particular depth always frozen, in summer is difficult to traverse.

Podzol soils can be found in forests of temperate climate, where the amount of precipitation(s) is greater than the amount of moisture evaporation. Top layers of podzol soils have small amount of salt, limes, iron, aluminum, but have big amount of quartz, which gives it whitish color, similar to the color of ashes. Lower layers contains larger number of clay parts than top layers, they are much thicker, hardly permeable for water that give possibility to form marshes. Locality with podzol soils, especially sabulous is well passable.

Black earth is characterized by black color, good fertility, according to the consistence predominantly from clay, loamy. In seasons of bad roads they are almost impassable for wheeled cars. There are a few elements that are able to form induced radiation in the consistence of black earth, but a little bit more than in podzol soils.

Chestnut soils are situated further south than black earth, according to the consistence predominantly clayey and loamy, in humid condition possess considerable plasticity and adhesiveness, and according to the passability are similar to black earth. Chestnut soils are salt, in the region of its spreading saline lands can be met.

Sierozem – is soil of near deserts or deserts, in the region of its spreading there are a lot of saline lands. Passability of sierozem soils is quite satisfactory. But in autumn and spring, when there is a lot of water in the upper layer they become almost impassable for wheeled cars.

Red soils are widely spread in subtropical and tropical regions.

Big squares of sandy deserts occupy sand. It can be met as a hillock, bed or hill. Hilly sand is typical in regions with unsteady wind direction, changing within a year. They gather near bushes in the form of chaotically situated hillocks of roundish or elongated size. There are quick hillocks with the height up to 1,5 meter, and packed with height of 14 meters. Its skids are usually loping, covered with moss or lichen. Hilly sands can be found predominantly in lower edges of mountain plain in regions where there is fresh or salty ground water. The largest hillocks have proper name and serve as reference points. Bed sands represent as narrow, long (up to a few kilometers) parallel waves, often fixed by growth. The height of bed sands is from 1 to 70 meters, bald up to 200 meters. The distance between crests is from ten meters up 2-4 kilometers. They are formed in the regions of desert, where winds of one direction prevail. Transported by wind sand is deposited in the form of billows – the most invariable formunder such winds. Usually beds have round crests, slopes depending on the size of sand grains have ascent 10-20 %. Between beds descents are formed with the width of 50-200 meters or more with firm clay or stony solid. These descents make it possible for troops to move. Sandy beds can serve as shelters for troops from ground-based observation. Sandy hills (sand dunes) are usually dry, blow with wind, not covered with growth. Sand dunes blow on firm soil (with deficient quantity of sand) are usually not high (from 0,5 to a few meters), but since can obtain the height of more than 100 meters. In the regions of sand-fields are formed simple-formed sand dunes of small or medium size (with height up to 20 meters), as well as complex-formed sand dunes of large size (with height up to 300 meters and more).

Depending on wind climate clusters of sand dunes have different shapes: of sand dune beds, situated according to the direction of predominate winds, stretched out along its resultant force; of sand dunes chains cross to opposite one another winds; of sand dune pyramids in the places of convection of votical flows, etc. Sand dunes without growth can move with wind with the speed of several tens of centimeters to several hundreds of meters a year.

Tykyry, solonetz, saline lands, blinders are found in deserted locality. Tykyry represent as horizontal clay-like places, situated in relief descents of sandy and stony deserts. They always appear to be the bottom of flat hollows. Sometimes lakes are formed in these hollows, supplied by water from melted snow and rainwater. While water drying, the tykyry surface turns into very smooth place, consisted of cracked plate. The sizes of tykyry vary from small place of several square meters to huge squares of several square kilometers. There no growth on tykyry. In dry season they are well passable; in rainy seasons they become limp on the depth of several centimeters and become almost impassable for wheeled cars. The surface of small water-tight tykyry can be used for gathering water from melted snow and rainwater. Solonetz represents as a region with salt soil. It is typical for solonetz to be boggy, sticky, swelling in humid condition, strongly packed and firm in dry condition. Very salty regions are called saline lands. After rain they turn into viscous, salty marshes. Blinkers are wet saline lands, situated in deep descents. In such places ground waters are situated high to the ground surface. In rainy seasons the bottom of blinkers is muddy, covered with salty mud or water, in dry seasons soil is tussocky, formed by dried mud and salt. Usually under the crust of dried mud, which breaks easily while troops and cars move is situated loose radial layer of soil, under which is extremely viscous layer. In rainy seasons blinkers are almost impassable for all means of wheeled and caterpillar cars. In dry seasons blinkers are passable for foot-passengers and pack animals.

Soil representation

Sands are showed on topographic maps when they have square more than 1 square centimeter in map scale. While representing on topographic map with scale 1:50 000 and 1:100 000 sands are divided into plain, hilly, bed, dune, cellular and sand dunes. All sands on topographic map with scale 1:25 000 are represented as plain; its relief is shown my means of horizontals.

Saline lands are represented on topographic map when they have square no less than 25 square meters in map scale. Herewith they are divided into passable and impassable. Impassable saline lines are showed by means of contours. Passable saline lines are showed by means of contours if they have square of 1 square centimeter in map scale, tykyry – with square of 25 square millimeters and more in map scale.

Marshes are represented on topographic maps by means of blue horizontal shading. According to the degree of passability for foot-passengers they are divided into passable, hardly passable, and impassable. Passable are marshes, where foot-passengers in summer can move in any direction. To such marshes belong mossy marshes with tight peat on the surface or under little layer(o,3-0,4 meter) of water, covered with grassy growth, and also marshes covered only with moss and a lot of shrubs (Labrador tea, heather, blueberry, etc.).

Hardly passable are marshes, where foot-passengers move with some difficulties (legs sink in the mud, footprint is quickly filled up with water). To this group belong marshes with a lot of hollows – places with water, loose layer of peat with big amount of sedge, cotton grass, flood plains, overgrowed with cane and rid, tussocky marshes with birches or alders, not covered with grassy growth.

Impassable marshes are deep muddy marshes, where foot-passengers cannot move and also with viscous soil, covered in summer with water. While representing marshes on topographic map plant formation is showed: grassy, mossy, cany, reedy. Different according passability and growth marshes are not divided by contours on topographic map. Marshes are represented on topographic maps if their square is 25 millimeters square or more in map scale. Hardly passable, impassable and passable marshes that serve as a reference point are represented even if they have smaller square. Marshes with depth from 0,5 to 2 meters are represented on topographic map with sign of its depth up to tenth parts of a meter. If a marsh has depth more than 2 meters there is a sign “deeper than 2 meters”. The bathymetry is indicated by point.