Azotomineralnotrofni micro-organisms in the vineyard soil

Abstract

Nitrogen is an element necessary for micro-organisms, plants and animals because it is a component part of or takes part in the biosynthesis of organic substances (albumins - proteins and proteids, carbohydrates - glicidi and fat substances - lipids) and macromolecules biocatalysts (ferments, vitamins, fito and cytohormones).

In the course of a year a vine (Vitis vinifera L.) produces about 20 tons of organic substances per a hectare (root, shoot, leaves and grapes) which is, calculated as dry substance, about 8.000 kg/ha. In order to synthesize that quantity of organic substances, about 4000 kg of carbon is reduced from atmospheric CO, from the atmosphere, for the production of which is used about 100 kg/ha of soil nitrogen in its mineral form. If the biomass produced by annual biochemical activity of micro-organisms is added as well, the nitrogen amounts are considerably larger. To provide nitrogen in the form of plant assimilative is, therefore, of a great importance for a successful wine growing production.

Plants use nitrogen through the root system but only in it’s mineral form dissolved in water forming NH₄ and NO₃. These nitrogen forms reach the soil mainly in three ways, these being: biochemical activity of soil micro-organisms - ammonification, nitrification (nitrite and nitrate) and the addition in the form of nitrogen mineral fertilizers. There is the fourth way as well - soil microflore in nitrogen fixation process, with the micro-organisms able to create ferment nitrogenase. Since there is no nitrogen in minerals and rocks, i.e. in the mineral part of the soil, the supply of plant nitrogen assimilative for the plants nutrition is very important, because the total contents of pedosphere contains 99% of its organic form the one not usable for the plants nutrition. Unlike plants, the soil micro-organisms can use nitrogen from the organic forms as well, these being fresh organic residues and humus. These micro-organisms are called azotoheterotrofni. However, together with plants, the mineral nitrogen form in the soil i.e. adsorption complex (1%), is used by the soil microorganisms (azotomineralnotrofni), too. The organisms using NH₄OH are called ammonium, NO₂ nitrite and NO₃ nitrate.

It is important to point out that the available quantities of the mineral nitrogen forms are used as food both to plants and these groups of micro-organisms. When these assimilative lack, there is a competitive relation between the plants and micro-organisms
in the soil considering the great presence of the micro-organisms in 1g of soil, they have the advantage, thus leaving the plants in shortage of these assimilative.