Substrate (biology)

Substrate in the context of soil is top of the basic material for various natural processes and technical applications, is usually as Granular matter before and often consists of crushed rock.

In the geosciences, the substrate (Latin pad ) is the starting material for soil formation, for example, the source rock at the site.

In horticulture with the term substrate culture media of all kinds described, including the grown soil, which is characterized by its particular soil type.

At the same time the ground is also substrate ( ecology) in the sense of a material, and in which organisms live. It contains the respective substrate ( Biochemistry) in the sense of to be implemented by various biomolecules and microorganisms chemical compound.

Substrates in horticulture

These are made of various earth by adding aggregates, from Erdgemischen or soilless substrates to the use of liquid nutrient solutions.

In the outdoor cultivation of nursery plants in orchards and field vegetable cultivation, the plants are mainly grown in natural soil; in a greenhouse the plants grow mostly in substrates which are more or less separated from the substrate. This is a result of the intensive use under glass (optimal growth conditions are economically necessary ) - in conjunction with the arid climate conditions ( salt accumulation in the soil) - and the need of closed culture methods for groundwater protection.

Classification of soils ( substrates )

Usually mixtures are used for earth -containing substrates. A main ground earth are referred to those which form the major portion of the substrate; operating earth prepared therefrom together with auxiliary earth or aggregates.

• Compost earth hotbeds gestures and leaves the earth among the main earth;

• Auxiliary earth are blended dung earth, peat soils, needle earth, heath earth;

• Aggregates are admixtures of sand, loam, clay, crushed brick, charcoal, marine algae, rock meal, etc.

It is also common for classification into the humus content in mineral soils on the basis of clay, sand and humus soils or humus mineral earth ( compost ). Soils with low pH are produced by peat: Nasstorfe bog earth and Trockentorfe of deciduous and coniferous earth earth.

Through sand and peat can be the nutrient content of the substrate decrease. Sand are as potted plants better stability and supports the drainage in the substrate. Peat is used because of the excellent water holding capacity and for better ventilation at high soil moisture. The clay content in the substrate is used to provide buffering capacity for nutrient salts; This is needed for example in the cultivation of roses.

Severity substrates have a high clay content, light earths predominantly sand and peat.

Industrially produced earth, substrates, aggregates

Standard soil and Torfkultursubstrate be used in horticulture as industrially manufactured earth. They are standardized and free of pests and diseases and compared with self-made operating earth often of lesser weight (transport an advantage). Examples are standard soil P for seedlings and cuttings, potting soil ED73 with slow-release fertilizer for heavy Zehrer; Torfkultursubstrate TKS with peat in accordance with DIN 11542, enriched with Hauptnährelementen and trace nutrients.

• Expanded clay, also Lekaton is used as a firming aggregate with low density in the earth or earth -free substrate for hydroponics;
• Perlite, vermiculite, expanded shale can be used as a mineral supplement low density for better air circulation, for example, cuttings earth, sowing the earth and Pikiererden;
• Plastics such as polystyrene peat ( polystyrene, water-repellent ) or Hygromull, polyurethane foam, are mixed as synthetic aggregates with a high water absorption capacity;
• In recent years, soil additives have been increasingly developed that are constructed and highly porous mineral and serve as water storage or ground optimizer, especially in semi-arid and arid areas. Additions with superabsorbent polymers ( hydrogel polymer ) are common. This water and nutrients stored composite materials are also suitable as additives for planting and growing media.
• Other organic additives are mostly waste from other productions, such as grass husks, wood fibers, coconut fibers, bark, etc.
• Rock wool from heated dolomite is used as earth -free substrate in vegetable and ornamental plants;
• Saatgel: A process developed by NASA nutrient gel for plant breeding.