What is organic nitrogen derived from?

Organic nitrogen is derived from biological sources, primarily found in manures and crop residues. This form of nitrogen is a crucial component of organic matter, which plays an essential role in soil health and fertility. When organic materials such as animal manure and plant residues decompose, microorganisms break down these substances, releasing nitrogen in forms that can be utilized by plants.

Manures, which include animal waste, are rich in organic matter and contribute significantly to soil nitrogen levels when appropriately managed. Crop residues, the remains of harvested crops, also provide organic nitrogen as they decompose in the soil. This process enhances soil structure, increases nutrient availability, and stimulates microbial activity, which further supports plant growth.

In contrast, other sources mentioned in the options, such as chemical fertilizers or industrial waste products, typically contain inorganic forms of nitrogen rather than organic ones. While atmospheric sources can contribute nitrogen through processes like nitrogen fixation, they are not specifically categorized as organic nitrogen sources. Understanding the origin of organic nitrogen is vital for effective nutrient management strategies in agriculture, as it helps promote sustainable practices and improve soil health.