Chemical reclamation of lands
Chemical land reclamation implies the system of measures of chemical effect on soil in order to improve its properties and raise the level of crop yield. At chemical reclamation, the salts harmful for crops are removed from the soil root layer, hydrogen and aluminum content will reduce in acid soils, and sodium content will decrease in saline soils. Presence of these elements in a soil absorption complex leads to deterioration of the chemical, physical-chemical, and biological properties of soil, and degrades soil fertility.
Chemical reclamation methods:
- Lime treatment of soils (mainly in non-chernozem/non-black soil areas) means application of calcareous fertilizers to change hydrogen and aluminum ions a soil absorption complex for calcium ions, which allow neutralizing soil acidity;
- Plastering of soils (saline and alkaline soils) means application of gypsum to reduce alkalinity: its calcium substitutes sodium in soil;
- Acidification of soils (with alkaline and neutral reaction) means acidation of the soils intended for cultivation of some plants (for example, tea plant) by applying sulphur, sodium disulphate, etc.
Chemical reclamation deals also with application of organic and mineral fertilizers in large quantities, which causes radical improvement of the nutrient status of reclaimed soils, e.g. sandy soils.
They have to resort to chemical reclamation in the cases when it is required to change the soil properties that are harmful to plants and improve its fertility. For this purpose, chemical compounds that improve or change soil properties are applied to soil. The most widely used method in agriculture is lime treatment of acid soils as well as plastering, and in some cases acidification of alkaline soils.
Chemical reclamation is advisable to be used for improvement of alkaline soil’s properties. Alkaline soils have the properties extremely unfavorable for crops which are due to the presence of significant number of sodium ions in the soil absorption complex (SAC) of these soils. It is higher concentration of sodium ions in soil that causes soil alkalinization process. As a result, saline soils with bad water-physical properties form. These soils are characterized by high viscosity, adhesiveness, heavy swelling of soil in wet condition and compactability in dried-up condition, as well as under low physiological availability of moisture.
Selected bibliography
Monographs and brochures
Kostyakov, A.N. - Fundamentals of land reclamation [in Russian] (1960) 
Textbooks and tutorials
Babikov, B.V. - Hydrotechnical reclamation [in Russian] (2002) 
Kolpakov, V.V., Sukharev, I.P. - Agricultural reclamation [in Russian] (1981) 
Regulatory and procedural guidelines and reference information