How do plants get the nitrogen when they need to grow?

Plants primarily obtain nitrogen from the soil in the form of nitrate (NO3-) and ammonium (NH4+), which are produced through the decomposition of organic matter and the activity of nitrogen-fixing bacteria. Some plants, especially legumes, can also form symbiotic relationships with nitrogen-fixing bacteria, allowing them to convert atmospheric nitrogen (N2) into a usable form. Additionally, plants may absorb nitrogen through their roots from fertilizers added to the soil. This nitrogen is essential for synthesizing amino acids, proteins, and nucleic acids, supporting their growth and development.