As podzol zone is very damp rain earthworm, mole and field mice have been spread most.
Relief of the zone is very complex. Surface here is very superficial low and it consists of heights. Being of such changeable the relief creates suitable conditions for spreading in the different forms of the dampness falling on soil. Or to be true, at low holes the dampness is less and in heights is very high comparatively. For this reason, we meet change in very different soil types in the podzol zone. Depending on factors forming soil that we noted above only podzol soils have been developed here. In general, depending on development of podzol soils of this zone sometimes under forest plants and sometimes under meadow plants soils of this place are divided into of 2 groups :1. Forest podzol soils. 2. Meadow podzol soil. Moreover in connection with passing the process of podzolling here, both groups are separated in semi types of soils, too:
1. Fatty podzol soils: Podzol layer is high in such soils.
2. Weak and middle podzolled soils: podzol layer in such soils are visible in the form of separate spots consist of full white layer of podzol of elluvial layer.
3. Strong podzol soil: elluvial layer of such soils consist of full white layer of podzol.
For its mechanical structure podzoil soils are divided to: clay, clayey, sandy soils and they differ from each other. In podzol zone soils in general had been developed on two basic rocks. First of them is sediments of clayey moren. And second one is generation of crystalloid rocks. It is necessary to note that mechanical composition of the podzolling process depends on mechanical composition of soil and nature of mother rocks. For its mechanical composition in light sandy soils podzolling process goes corporately strong than in clayey soils. In lands formed on moren sediments podzolling process passes comparatively stronger than soils formed on los rocks. Finally plant cover has direct influence on characteristic podzolling process. At result of researches carried out it has been clear that most typical podzolled soils had been developed under forest plants. But meadow plants have rather slow pozdolling process.
Morphology of podzol soils
In typical podzol soils one can find clear genetic layers separated one by one sharply in the soil in the general view of the soil. Here upper layer is "A" – rotten -elluvial, "B" is ellüvial, and "C" is illuvial layer. In podzol soils below given two following layers of "B" and "C" is considered as characteristic layers. Elluvial "B" layer is in white snow color in podzol soils and has been separated from upper rotten layer sharply. But illuvial "C" layer is sediment of iron compounds washed away from top. Therefore, iron compounds are scattered in separate nests in illuvial layer. This layer is called ortshtein layer. Undoubtedly depending on iron compounds the coloro of illuvial layer is yellowish and sometimes reddish. Humus’s amount in average is about one -4%. Reaction of the soil solution is acid. In podzol zone, especially in eastern part of the zone it is possible to note swampy soils from intrazonal soils. Here formation of such soils depends on such uneven soil and abundance of the rainfall. Swampy soils as spread among podzol soils, so they were also podzolled more or less. Such type of soil is called as podzolled swampy soils. One of features of podzolled swampy soils is presence of FeO layer under illuvial "C" layer.
Essence of the Podzolling process.
Depending on natural condition of the podzol zone land formation process here receives a special character, too. These sols always are under rainfall and evaporation influence being under forest so these soils were saturated by dampness and subjected to washing off process. When soils are washed off constantly from one side mineral matters in podzol soils are washed to lower layer from top layers in organic matters. First of all washable compounds and secondly hardly washable CaCO3 and Mg CO3 is washed off.
Plant layers form sour humus in such forests in the result of rotting. Gradually by filtering of similar acid solutions from soil layer washing off Ca, Mg cations from soils becomes stronger. So, Ca, Mg compounds when diminished in soil layer the influence of hydrogen ion passing to soil via waters gets increased even greater. As hydrogen ion cannot find anti cation inside the soil it is located in absorption complex of soil and so such type of soils turn to be unsaturated soils. Hydrogen ion creates acidity reaction in the soil environment. This acidity influencing absorbing complex of soil and loses its solidity and becoming broken to pieces gradually. Mineral part of absorbing complex faces with deep changes. Alimo and Fe silicates inside of it are separated O3, Al2 O3 and SiO2 compounds becoming broken to pieces.
Aluminum and ferrum compounds and Ca, Mg, K compounds are washed from top layer of soil to lower layers due to influence of organic acids. These compounds, especially ferrum settle in illuvial layer of podzol soils and create afire mentioned ortshtein compounds. But SiO2 compound settles in top layer (illivial) in amorphous shape and creates podzol layer in special whitish color. So, is possible to say that forming of the podzol layers of these soils came forward due to broken absorbing complex and accumulation of SiO2 matters. Acidity reaction of podzol soils cause loses of organic matters and humus in soil. For this reason despite of plant remainders on podzol soils the level of humus is about 1 to 4% Podzol soils play big part in the agriculture. Therefore, to improve the property of the soil some chemical measures are carried out. High acidity of podzol soils is harmful for agriculture plants. Therefore, this is necessary to replace hydrogen ion in absorbing complex with another cation to neutralize acidity. It has been found in the result of carrying out experiment that to improve podzol soils they are calcified from time to time. Ca cation in lime replaces hydrogen ion in absorbing complex and causes gradual improvement of soil structure and neutralization of reaction. So, podzol soils are turned as cultural soils for agriculture
Black type soils
Plain zone has settled in the southern east part of the podzol zone. This is black type of soils that developed in the zone basically. Area of the grey zone is equal to 2.5 million km2. Therefore, black type soils take fewer places compared to podzol soils in the territory of the USSR. Climate condition of the zone is different. But north half part has moderate cold, south half part has comparatively moderate hot drought climate. But amount of the rainfall on average is till 420-500 mms, average annual temperature is 6°-8°. Climate condition of the zone creates conditions for washing of matters in the land with the help of rainfall. Therefore salts like NaCl, KCl and Na2 SO4 is sometimes seen in lower layers of soils. CaCO3 compounds are spread inside of "white peeps". Black soils have developed on lös and lös-like rocks mostly.
But moren sediments are considered as mother rock for black soil in the north part of the zone. At last at the edge of the zone in the shores of Azov Sea formations of black soil were noted on saline clayey rocks and on basaltic crystalloid rocks in Transcaucasia (Armenia). Lös and lös like rocks are considered as most typical rocks for black soils. As los rocks are rich of CaCo3 compounds the absorbing complex of soils formed on them are always in saturated condition. Regarding relief of zone its northern part is uneven and southern part has even relief. Such calamity of this zone creates suitable conditions for washing of the soil. It had been found in the result of wide investigations that this zone was without forest since ancient time. Therefore not forest plant but pedicel plant plays main role in forming of the black soil. Plain plants of the zone are very different.
Plants are divided into two semi-zones for cover. Meadow plants have spread in the north, and “plain” plants from typical grey plants are spread in south semi- zone. Richness of humus matter of black soils is explained with abundance of remainders of grass plants in this zone throughout the year and as plain plants have very deep root system it increases amount of organic remainders. Suitable condition of the climate turns fine plant gradually to humus by rotting them completely. Wide root system of the plain plants passing to land layer from width and depth, it plays big part in forming of the granular structure of the soil. Following features are typical for black soils.
1. Black soils are rich with rotten matters. Humus of typical black soil sometimes reaches 18-20%. Rich humus in this soil and falling of plant remainders on soil throughout a year and strong humus process in this zone depending on climate is explained with given factors. Humic acids take more places in composition of humus of black soil. As we know, humic acid as a whole gives durability to humus.
2. That black soils are rich of mineral matters.
As we mentioned above black soils are enriched with mineral matters depending on structure from level of mother rock. As we mentioned above black soils are created on rocks of lös or lös like rocks.
Therefore black soil become rich with mineral matters to composition depending on character of the mother rock, too.
3. That black soil is rich with bases enough. Ca cation is located in absorbing complex of these soils. Saturation of black soils with bases is explained with mother rocks rich with CaCo3 compounds. All black soil move from west to east and has different natural condition. Depending on this condition all zone is possible to split to separate type of black soils that we noted below:
1. Changed black soil
2. Washed black soil
3. Typical black soil
4. Simple black soil
5. Southern black soil
6. Azov shore black soil
Washed black soils
Humus of washed black soils reaches 4-6%. But thickness of humus ranges from 30-40 cms. Washed black soils are located at northern part of zone in the shape of one thin zone. As climate condition of this place is damp majority of parts undergo to washing process. Therefore, soils lose their humus matter gradually, and get weaken from point of view of Ca, Mg compounds. Therefore, such soils are called as black washed soils.
Typical black soils
These soils occupy major part of the zone. Such soils are found in Belorussia, Ukraine, Voronej, Penza oblasts. Characteristic signs of the typical black soil are rich humus content.
Average amount of humus reaches thickness 14-16% and thickness of humus layer – 1.1-1.1.5 meter Carbonate compounds are met seldom in lower part of typical black soils. Reaction is neutral. Soluble harmful salts are found in typical soils.
Simple black soils.
They organize passage zone between typical black soils and southern black soils. Therefore morphologic signs of these soils morphologic signs related to sometimes to typical and sometimes to southern black soils. Simple black soils differ from typical black soils for amount of humus and thickness of humus layer. Thus amount of humus reaches 6-10% and thickness of humus layer 40-50 cms.
Black south soils
These soils are located at drought zone of south. Depending on natural condition humus of black southern soils is not more than 4-5%. But thickness of humus is till 40-45 cms. Carbonate compounds in southern soils are met on top layers. But reaction of the soil is weak alkali.
And being typical gypsum sediments are found in”C” layer of southern black soils. Such new formations are sometimes in crystalloid dots forms and sometimes in thin vein form. Southern black soils are found in major cases like lose and sometimes on formations of saline clays. Therefore, saline black soils like separate spots were spread on southern black soils, too.
Azov shore black soils.
Such black soils stretch from eastern shores of Azov Sea till east foothill of the Caucasian mountains. But amount of Humus is 5-6% and thickness of humus layer is till 1.5-2 metres. Depending on comparatively less humus soils in shores of Azov Sea are dark grey and brownish colors. Southern black soils are rich with CaCo3 compounds. So separate spot like of vein shape CaCo3 compounds are found at top layer of soil. Such soils are mainly located in Rostov and Northern Caucasus.
Changed black soils.
Changing of the black soils has come forward from the influence of the foreign factors. Changed black soils have been located in the northern edge part of the zone in the neighbourhood of the podzol zone. As podzol forest soils change forest plants in the Podzol zone and covered by grey zone forests plants here are changed deeply.
As we know, forest cover will change condition of climate of the zone in the first place. Forest Cover increases dampness in the soil and also it creates suitable conditions for appropriate approbation of rainfall falling on soil. Therefore, it creates deep changes in black soils with passed dampness. At first stage rotten matters of black soils are divided under influence of dampness and being washed. Humus of the soil diminishes gradually, but the color of top layer is lightened from this reason. Later neutral reaction in black soils like in podzol soils turns to acid reaction under influence of dampness. Under influence of this reaction silicate and alimo –silicate parts of absorption complex are divided in small compounds (SiO2 Al2 O3, Ca, Mg and etc.) Here divided Al, Fe compounds are washed from top layer to lower layer and accumulated there.
But SiO2 compound begins gathering in the layer of upper eluvial. This case is similar process like formation of podzol soils. When this process continues, and as SiO2 compound increases in changed black soils, these soils can turn to podzol soils. Therefore, podzol soils created from changed black soils are called as repeated podzol soils.
The importance: (Of black type soils) as black type soils are rich in matters, and as water-air regime is sufficient, they are considered as productive soils compared to other soils. One of positive peculiarities of the soil is presence of very thick humus. Therefore, plant root has found corresponding condition for development. As black soils are rich in mineral matters there is no need for artificial fertilizers. It is necessary to guard from dampness of the soil as far as possible for increasing productivity of the soil. This helps to keep snow cover on soil in the artificial way, and to carry out tillage in time.
Formation of desert-plain type soils.
In the south and south -east of black soil zone wide desert plain or dry plain zone is located. Climate of the zone is continental. So, summer months are hot for long time and winter months are short cold. Absolute dampness of the air and dampness is low, too. Constant winds blowing here increase the drought of the zone even greater. Desert-plain zone in the territory of the USSR occupy around Volga, Kazakhstan and eastern parts of Azerbaijan. Moreover this zone occupies small areas in foothills of the Caucasian mountains and the Crimea, too. Soil cover of this zone is different. Types of land which have been spread basically are chestnut in desert-plain zone, grey and brown soils. From geographical view point soil types noted by us occupy various areas inside zone. Chestnut soils in the north side of the desert-plain zone, brown soils in south and grey soils in southern part of zone are located. Moreover depending on climatic condition and structure of mother rock irregular, saline soils are spread her.
Chestnut and brown soils.
Such type of soils occupies major part of desert-plain zone. Such type of soils is found in northern part of Crimea, in Azov and Black Seas, in eastern part of Northern Caucaus, at bottom of the Volga, northern Kazakstan and in the Uzbekistan.
But these soils are spread in the east part of the territory of the USSR in the surroundings of the Ural, Altay, the Balkhash, Turan plain and then in Buryatua and Mongolia. Besides plain places brown, chestnut soils are found in mountainous parts of Turkmenistan and Kyrgyzstan, too.
Area of spreading of brown chestnut type soils is specified by natural condition. Amount of the rainfall is less (200-350 mms) here comparatively. The highest average annual temperature is available here. (20—25C) main mother rock reddish, brown clay los and Caspian Sea sediments.
These rocks have well soluble salts in contents except los rocks. Plant cover is very weak for black soil zone. But plain plants in chestnut soil, desert plants on brown soils are spread. Depending on less remainders and drought of climate these remainders are not subjected to process of rotting and as it mineralized quickly the humus in these soils are formed less.
Structure of earth consists of even and weak wavy plains.
Non-strike, small slope, hole and hills were separated on these plains. Such small relieves play big role in formation of chestnut and brown soils. Because small hole and hills cause even spreading of dampness and create very different soil changes.
Therefore the characteristic feature for this zone is complexity of soil. That is in very short distances one soil replaces other. Chestnut soils took its name from color of soil. Therefore typical color for chestnut type soils is dark brown and brown color. Amount of humus is 3-3%. Depending on humus amount chestnut type soils generally are: dark chestnut, chestnut and light strong chestnut and they differ from one by one. According to chemical composition decreasing gradually humus amount in separate generic layers is possible. For instance:
Humus in "A" layer -4.2 %
3.2% in "A2" layer
2.8 % in "A3" layer
2.2 % in "B" layer
But 0. 9%" in C" layer
Thickness of humus reaches to 40-60 cms in the dark strong chestnut soils. Absorbing complex of the chestnut soil is saturated by Ca, Mg cations. Sometimes Na cation is met in absorbed conditions, too.
It shows salinity of the chestnut soils, too. Presence of Na cation in absorbing complex influences structure of soil. Due to unstable structure of soil in saline and chestnut soils, it quickly violated under water influence, and turns sometimes to layer and sometimes to clear unstructured shape. Brown soils differ from chestnut soils for less humus and lightness of color. Thickness of humus layer is 30-35 cms in brown soils and amount of humus is 2-3%. Amount of humus in soils, while passing from top to lower layer like in chestnut soils diminishes gradually. e.g. it is 1.8% in A layer, 1.2 in B layer and 0.8% in C layer.
Depending on amount of humus, brown soils are divided into following soils changes: dark brown, brown, light brown. Brown soils are weak for agricultural purposes compared to chestnut soils. For effective usage of these soils there is certain need for artificial fertilization and irrigation.
Grey soils.
These soils have been located in the South side of the plain zone. Grey soils especially have been spread in the Central Asia and Transcaucasia widely. Natural condition of the grey soils consists of our below given notes. Here amount of the rainfall is 100-120 mm. and evaporation is very high. Plant cover consists of xerophytes plants from the minority of the dampness. Plants like camel prickle, wormwood and salt loving plants were developed especially. Plants here have not organized full cover and it has developed irregularly. But mother rock consists of lös and saline sea sediments. Morphologically grey soils were developed weakly. Depending on natural condition, land formation process in grey soils passes weakly. Therefore for outward appearance it is not possible to select separate genetic layers in profiles of grey soils. Color of the grey soils is light grey, whitish. It is explained with minority of humus in soils. By average humus of grey soils is one - two percentages. In some cases it is les than 1%. Grey soils are considered from soils which have been saturated by bases.
Therefore calcium cation has been located in the absorption complex. But in solutions of grey soils Na cation plays big role. In some cases Na cation if predominating then the grey soils can turn to saline grey soils. . Characteristically in desert and zone saline soils were spread. These soils are considered from introzonal soils. Forming of saline differs with being of the salty soils waters and salty rocks.
Grey soils are considered weak soils like brown soils. Especially food stock of the grey soils is less compared to brown and chestnut soils. From this reason grey soils need irrigation and nitrogenous, phosphorus fertilizers.
Formation processes of the saline soils
We have noted above formation of saline soils on black or chestnut soils in desert and plain zones, on grey and brown soils. According to researches carried out by academician Prosolov saline soils occupy 10% of area of the USSR. Saline soils were spread in drought zones in the USSR. These oils occupy 1 million km2 of area. Transcaucasia and Central Asia occupy big areas. In studying of saline soils works of scholars like Hedroyds, Prasolov, Kovda, Dimo will be useful. Saline type soils have very various changes. Among most spread from them: saline, malt
Saline soils: Saline or salty soils are said to be the most salty soils in the upper layer. Such salts harm to cultured plants. In general, amount of the salts on top layer of saline soils is more than 3%. Forming of the saline soils passes in the very different condition. At first salted mother rocks have influence on creation of salts in saline soils in such amount. Such mother rocks are found in Central Asia and Caspian Sea in Azerbaijan and Aral seas. Moreover winds in these drought places take from sea coast and deliver to top of soils and it plays a big part in increasing of salts. Finally salty soil water have great role in formation of saline soils in plains. Under influence of high evaporation soil waters, which are not in depth take salts to upper layers via soil capillaries and create saline soils here.
