Certified Crop Advisor Practice Exam

Soil organic matter is a source of _____ for crops?

1. Phosphorus

2. Potassium

3. Nitrogen

4. Calcium

The correct answer is: Nitrogen

Soil organic matter plays a crucial role in providing essential nutrients to crops, with nitrogen being one of the most significant. Organic matter is formed from decomposed plant and animal materials, which contain nitrogen in stable forms that can be beneficial for crops. When organic matter breaks down in the soil, it releases nitrogen in a form that is available for plant uptake, contributing to their growth and overall health. Nitrogen is vital for various plant processes, including the formation of amino acids, proteins, and chlorophyll, which are necessary for photosynthesis. Unlike some nutrient sources, the contribution of nitrogen from soil organic matter is both immediate and sustained over time, as organic matter continues to decompose and release nutrients slowly. In contrast, phosphorus, potassium, and calcium, while important for plant health, are typically derived from different sources such as fertilizers or mineral sources rather than being primarily associated with soil organic matter.