Global food demand is increasing rapidly, which consequently leads to intensive soil treatment and the use of different pesticides and fertilizers to enrich the soil with nutrients that are needed by plants in order to grow. With intensive usage of soil in agriculture and horticulture, the use of calcium cyanamide as fertilizer is recommended, however, it shall be used with certain restrictions. Calcium cyanamide is a slow-release fertilizer made from natural compounds. The use of calcium cyanamide can have negative effects on some soil organisms such as for instance earthworms, which are considered one of the most important terrestrial organisms, as they represent a major share of organisms in the soil and are important decomposers. The effects on organisms are checked with standardized ecotoxicological tests, and in this master's thesis, these are the guidelines of the standardized tests OECD no. 222 and ISO 17512-1.
This master’s thesis compares the effects of commercial formulation of calcium cyanamide on earthworms Eisenia andrei. In determining its effects on the growth and mortality of earthworms, it was discovered that the commercial formulation of calcium cyanamide at higher concentration negatively affects the growth of earthworms and increases their mortality. Negative effects of commercial formulation of calcium cyanamide were also detected with regard to earthworm reproduction. The second part of master's thesis explores how earthworms avoid the commercial formulation of calcium cyanamide.
It has been established that low concentrations of commercial formulation of calcium cyanamide most probably create favourable pH for earthworms which therefore prefer to choose contaminated soil, while higher concentrations of commercial formulation of calcium cyanamide cause earthworms to avoid contaminated soil.
It can be concluded from the results that higher amounts of commercial formulation of calcium cyanamide are toxic for earthworms.
|
