Air and greenhouse gas emissions

Increase in soil bound carbon content

Carbon in the soil occurs in two forms: in mineral compounds, which include carbonates, and in organic compounds derived from the decomposition of plants, bacteria and animals. In simple terms, organic carbon is called soil organic matter, of which humus, or humus, is an essential part.

Adequate carbon, especially in organic form, is essential for plant growth and development and consequently for profitable crop production. However, as a result of intensive agrotechnical measures, the removal of biomass from fields and the natural oxidation of carbon by soil micro-organisms, the amount of carbon may decrease significantly, leading to significant soil degradation. Hence, it is necessary to take measures to restore the soil to as high a content of this macronutrient as possible.

The simplest way to increase organic carbon is to deliver it to the field. This can be done in two ways:

  • providing, among other things, organic matter as fertiliser. We are talking about fertilisers such as compost, manure, slurry, slurry, but it is also possible to take plant residues to the field or leave them there. The use of components made from young lignite – lignite – is also becoming increasingly widespread.
  • the use of so-called green manures, i.e. crops grown as intercrops or catch crops that are shallowly ploughed in or mixed into the topsoil.

Both methods mentioned are beneficial, as both animal and green manures can, in addition to lignite, be rich sources of nitrogen. It is the carbon/nitrogen ratio that is one of the important parameters informing soil fertility.

The provision of plant residues to the soil or the cultivation of plants for green manure is always a positive measure aimed at increasing the humus content of the soil. However, it is worth knowing that the decomposition of plant residues and the consequent positive effects of the presence of organic carbon for crop plants depend on the biomass used. Green manures, which contain less so-called lignins that decompose slowly in the soil, have a much faster effect. An example of lignin-rich biomass is cereal straw. Fabaceous plants, on the other hand, contain significantly less lignins and therefore decompose much faster. In addition, faba bean plants fix nitrogen from the air and effectively compensate for nitrogen deficiencies in the soil. This group of plants is therefore particularly predestined for use as green manure. Any type of organic matter is valuable, and increasing the organic matter content of the soil always pays off. At the same time, it must be remembered that while soil degradation involving a reduction in humus content can occur very quickly, it can take up to several years to rebalance and restore the soil’s optimum carbon content. The use of lignite components improves soil quality in a long-term and stepwise manner.

Increasing the humus content of the soil improves soil fertility and the efficiency of the carbon fixation process from the air. More on this topic on the following pages: