After spreading moisture in the soil induces calcium cyanamide to convert over several intermediate stages into fertilizing lime and plant-accessible ammonium nitrogen. In the first partial reaction calcium cyanamide is converted into lime and cyanamide. The intermediate product cyanamide is then converted via urea fully into plant-accessible ammonium. Contrary to widespread opinion when calcium cyanamide converts no poisonous cyanide gas is produced that might leak from the soil. What is produced is actually cyanamide, which remains in the aqueous soil solution and which is responsible for the special effectiveness of the calcium cyanamide.
The decomposition of calcium cyanamide in soil:
A part of the cyanamide reacts further into dicyandiamide (DCD). This DCD has nitrification inhibitory properties, i.e. it delays the conversion of the ammonium nitrogen into nitrate that is caused by certain soil bacteria (Nitrosomonas and Nitrobacter).
Schema of nitrification:
Dicyandiamide inhibits soley the activity of the Nitrosomonas bacteria, and not that of Nitrobacter. This means that no plant-damaging nitrite can accumulate in the soil. Generally speaking, calcium cyanamide converts in the soil via two phases:
Reaction phase and fertilizing phase
During the reaction phase calcium cyanamide undergoes the first steps of decomposition and develops a strong alkalinity. This creates a favourable environment for beneficial soil microbes and for a healthy growth of the crop. This phase continues for between 8 to 14 days in the soil depending on reaction conditions. The reaction rate depends on the moisture, temperature and activity of the soil, its humus content and the quantity of fertilizer applied.
It should be emphasized that no harmful residues remain in the soil. The cyanamide is completely transformed into urea, thereby improving the nitrogen nutrition of the plants. The nitrification inhibitor dicyandiamide also slowly decomposes into urea. This means that in the end everything is made available as a nutrient to the plants in the form of nitrogen and lime, with no non-soil decomposition products formed.