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

1. Analyze the Question

The question asks about the biological and chemical process that occurs when organic matter (dead plants and animals) containing nitrogenous compounds (like proteins) decomposes in the soil. Specifically, it asks for the primary product formed during the initial stage of this decomposition.

2. Explain the Concept

This process is part of the Nitrogen Cycle, specifically the stage known as Ammonification.

• When plants and animals die, their bodies contain complex nitrogenous compounds such as proteins and amino acids.
• Decomposers, such as bacteria and fungi in the soil, break down these complex organic nitrogen compounds.
• The first major inorganic nitrogen product released into the soil during this microbial breakdown is ammonia ($NH_3$).
• In the presence of soil moisture, this ammonia quickly reacts to form ammonium ions ($NH_4^+$), but the primary conversion product from the organic material is ammonia.

3. Show the Solution

• Step 1: Identify the source material. Dead materials contain organic nitrogen (proteins).
• Step 2: Identify the process. Microorganisms (decomposers) act on these proteins.
• Step 3: Determine the product. The enzymatic breakdown of proteins by soil bacteria releases nitrogen in the form of ammonia ($NH_3$).
• Step 4: Evaluate the options. While ammonia can later be converted into ammonium salts or nitrates (through nitrification), the immediate conversion product from the nitrogenous compound in dead matter is ammonia.

4. Identify the Answer

The correct option is A.

5. Exam Tip

Remember the sequence of the Nitrogen Cycle: Nitrogen Fixation → Ammonification → Nitrification → Denitrification.

• Ammonification = Dead matter to Ammonia.
• Nitrification = Ammonia to Nitrites ($NO_2^-$) then to Nitrates ($NO_3^-$).
• If you see "dead materials," always look for ammonia as the starting point of the cycle in the soil.