- •Department of Soil Science & Soil Conservation
- •Introduction
- •2. General scheme & processes of soil formation.
- •3. Morphological features of the soil profile.
- •4. Soil ecology.
- •Study outline:
- •1. Soil definition and the factors of plant growth.
- •2. Plant roots and soil relations.
- •3. Soil fertility and soil productivity.
- •4. Soil texture.
- •1. Sources and composition of som.
- •2. Residue decomposition and humus formation.
- •3. Agronomical and ecological roles of som.
- •4. Maintenance and balance of som.
- •2. Nature and properties of soil colloids.
- •3. Pole in soil genesis and soil productivity development.
- •4. Types and practical significance of soil absorbing capacity.
- •2. Soil Properties as Effected by Exchangeable Cations.
- •3. Soil Acidity & Acid Soil Amendment.
- •4.Soil Alkalinity & Sodic Soil Amendment.
- •5. Soil Buffer Capacity & Significance of Soil pH.
- •2. Managing soil structure.
- •3. Particle density and bulk density.
- •4. Soil porosity and aeration porosity.
- •5. Mechanical properties of mineral soils and their management.
- •2. Soil Water Movement.
- •3. Plant and Soil Water Relations.
- •4.Soil Water Regime.
- •6. Soil Water Management.
- •1.1. Composition and concentration of soil solution.
- •1.2. Osmotic pressure of soil solution.
- •1.3. Redox potential and redox processes in the soils.
- •2. Soil air, a gaseous phase of the soil.
- •2.1. Soil air composition and properties.
- •2.2. Plant requirements to soil aeration.
- •3. Management of soil redox and aeration regimes.
- •1. Soil temperature & modes of energy transfer.
- •2. Conduction of heat in soil. Heat-related soil properties.
- •3. Thermal conductivity of soil.
- •4. Thermal regime of soil profiles &its control.
- •2. Principles of soil cover zoning in Ukraine.
- •3. Soil Zoning in the Mountain regions.
- •4. Fao nomenclature of soils.
- •2. Soddy Podzolic and Soddy Podzolic Gleyed soils.
- •3. Soddy soils.
- •4. Bog and Peat soils.
- •5. Practices of soil management in Ukrainian Polissya.
- •2. Grey Forest and Podzolized soils.
- •3.Chernozems of the Steppe Zone.
- •2. Dark chestnut and chestnut soils.
- •3. Salt-affected soils.
- •4. Practices of soil amendment and land use improvement in the arid steppe zone.
2. General scheme & processes of soil formation.
General scheme of endogenesis, regard less of it's concrete form is composed of five component groups of processes: (1) transformation of minerals (weathering), (2) transformation of SOM consisting of decomposition, humification & mineralization, (3) formation of organic-mineral derivatives with varying extend of complexity, chemical & molecular bonding, (4) accumulation of nutrients & improving the condition of plant (root) growth in the upper, most rich in plant roots & microorganisms part of a soil profile, & (5) translocation of the products of soil formation in the profile by their vertical movement. All of these groups of processes possess certain specific features depending on the factors & conditions of soil formation.
From the information mentioned above, it follows, that any kind of a pedogenic macroprocess is the interaction between the great geologic and small biologic cycles of matter & energy on the earth.
In this country the theory of soil formation is based on genetic principles developed by V.V. Dokuchaev. Some processes are relatively simple: dissolution & precipitation, wetting & draying, freezing & thawing, microbial synthesis & decomposition, flocculation & deflocculation, etc. These are the pairs of dialectical opposites. They are termed microprocesses. Microprocesses, developing in time in some specific settings of the factors & conditions of soil formation become periodic & space-specific. They give rise to the mesoprocesses of soil formation, which are also called elementary processes of soil formation & which are responsible for the formation of specific horizons of soil profile. Mesoprocesses of varying intensity united in groups beget macroprocesses of soil formation responsible for the formation of specific soil profiles. Let’s briefly consider some of the most widespread mesoprocesses.
Humus formation (humification). The process whereby the carbon of organic residues is transformed & converted to humus substances through biochemical and/or chemical processes. Humus formation may be accompanied by humus accumulation when there is enough organic residues for the process.
Podzolization. Primary & secondary minerals are decomposed by the action of acidity formed from the decomposition of organic residues in the forest. Under conditions of high precipitation, iron & aluminum oxides (sesquioxides) are released in weathering. These oxides, according to I.S.Kurichev (1970), complex or chelate with OM and are transported to the subsoil, resulting in the formation of an illuvial horizon. The loss by eluviation of sesquioxides & clay during the podzolic process, tends to leave behind a light-colored (rich in amorphous SiO2 ) elluvial horizon.
Swamping is the formation of swamp or bog soils. The first stage of this process may be gleization. Gleization may be followed by the formation of histic horizon. Where soil development occurs under conditions of extreme wetness, as in swamps or lakes, epipedon (diagnostic surface horizon) is organic in nature. By the degree of decomposition of the OM in histic horizons, they may be fibric, hemic or sapric. Peat is unconsolidated soil material consisting largely of undecomposed, or only slightly decomposed, OM accumulated under conditions of excessive moisture.
Salinity development (salinization) is the enrichment of soil profile with soluble salts mainly by capillary rise. Saline soils contain sufficient soluble salt to adversely affect the growth of most crop plants.
Sodicity development (alkali soil development) is the adsorption of exchangeable sodium by the SAC leading to the drastic changes in profile features and productivity of soils. Sodic soils, according to K.K. Gedroiz, develop from the leaching by water of some saline soils, especially those containing Na2CO3. Excessive exchangeable sodium adversely affects crop production & soil structure.