The nitrogenous compound in dead materials in the soil is converted to

In the nitrogen cycle, when organisms die, their proteins and other nitrogenous compounds are broken down by decomposing bacteria in a process called ammonification (or decay). The first product of this decomposition is ammonia (NH₃).

The process occurs in stages:

1. Proteins in dead material are broken down into amino acids by proteolytic enzymes from decomposing bacteria and fungi.
2. The amino acids are further deaminated (the amino group -NH₂ is removed), releasing ammonia (NH₃).

After ammonia is produced, nitrifying bacteria can convert it further: first to nitrites (dioxonitrate(III), NO₂^-) by Nitrosomonas, then to nitrates (trioxonitrate(V), NO₃^-) by Nitrobacter. However, the question asks specifically about the first conversion product of nitrogenous compounds in dead materials, which is ammonia.