Recultivation of lands

Recultivation of lands implies a package of measures aimed at the restoration of productivity of the lands disturbed in the course of nature management as well as improvement of environmental conditions.

Disturbance of lands means the process occurring during mining operations, carrying out of geological survey, exploration, construction and other works and causing disturbance of topsoil, hydrological regime of a given area, formation of anthropogenic relief, and other quality changes of land conditions.

Recultivated land is disturbed land the productivity and economic value of which is restored and its environmental conditions are improved.

Land restoration is divided into two stages:

1. Technical stage deals with preparation of lands for further intended use.

2. Biological stage involves fertility restoration performed after the technical stage; it includes a package of agrotechnical and phytomelioration measures aimed at restoration of historically established system of flora, fauna, and microorganisms.

The recultivation works consists of the following stages:

  • Design and survey works (soil surveys and other field investigations, laboratory analysis, mapping);
  • Determination of the characteristics of the site cleaned: engineering-geological measures, qualitative and quantitative pollution indices, microbiological and agrochemical measures of the cleaned soil;
  • Pollution localization;
  • Bunding, application of sorbent agents;
  • Cleaning of the area from pollution;
  • Mechanical, sorption and microbiological cleaning;
  • Chemical and microbiological control of the cleaning process;
  • Purchase of fertile soil layer (if needed);
  • Putting of potentially fertile rocks and fertile soil layer on the lands being restored;
  • Liquidation of industrial sites, transport communications, electric networks, buildings and structures, and other facilities (if needed);
  • Cleaning of the recultivated area from industrial waste;
  • Installation of drainage and water supply network for further use of the recultivated lands (if needed);
  • Purchase and planting of seedlings;
  • Preparation of bottom, installation of borrow cuts and other excavations for making water bodies in them (if needed);
  • Rehabilitation of the fertility of recultivated lands made available for agricultural, forestry and other uses (purchase of seeds, fertilizers, ameliorants, and their use, etc.).

Causes of occurrence of disturbed lands and water bodies

There are the following types of the human activities leading to the need for recultivation of lands and water bodies:

  • economical activity
    • mining operations, especially opencast mining;
    • deforestation;
    • appearance of dumps;
    • urban planning;
    • construction of hydraulic works and similar facilities;
  • conduction of military tests, including nuclear weapon tests.

Two basic stages of recultivation

Recultivation works are usually divided into two basic stages: technical and biological. At the technical stage, landscape preparation is carried out (filling up of ditches, trenches, pits, depressions, ground gaps, leveling off, and terracing of industrial waste banks), hydraulic and reclamation facilities are constructed, toxic waste is buried, fertile soil layer is applied. As a result, land reclamation is provided. At the biological stage, land treatment works are carried out to improve soil properties.

Directions of land recultivation

Depending on the purposes set, they distinguish between the following directions of land recultivation:

  • nature conservation;
  • for recreational purpose;
  • for agricultural purpose;
    • plant growing;
    • grassland development;
  • forestry;
  • for hydroeconomic purpose.

Plants used at land recultivation

Among the plants used to improve land quality were first herbaceous plants of legume family that can fix air nitrogen. For example, for recultivation of the territories of coal mines in Australia ternate clitoria (Clitoria ternatea) is used. Another plant regularly used for land recultivation is black poplar (Populus nigra).

Recultivation period can last ten years and more. It includes technical and biological stages.

Technical recultivation stage (technical recultivation and mining engineering recultivation when rehabilitating the lands disturbed by mining works) includes the following types of works: stripping and storing of fertile soil layer; surface leveling; transportation and application of fertile soil on the surface being reclaimed; construction of drainage and water delivery canals network; installation of soil-saving facilities. The technical stage of restoration is performed by mining enterprises.

Biological recultivation stage (biological recultivation) includes the measures aimed at rehabilitation of the fertility of recultivated lands and restoration of flora and fauna. At this stage, the works are executed by forestry or agricultural enterprises to which a given land parcel will be assigned for permanent use after its technical recultivation.

There are several directions or types of recultivation which are characterized by specific approaches and methods depending on the use of the restored area for intended purpose. The following directions of recultivation have become the most popular: agricultural; forestry; fishery; hydroeconomic; recreational; sanitary and hygienic; and construction.

Recultivation of lands should have integrated nature, i.e. to provide for their further use for various purposes.