What is the chemical uptake form of nitrogen in plants?

Plants primarily take up nitrogen in the forms of ammonium (NH4+) and nitrate (NO3-), but nitrate is the most common form used during the growth stages of many crops. Nitrate is highly soluble in water, allowing plants to absorb it readily from the soil solution. Once inside the plant, nitrate is converted into amino acids and other nitrogenous compounds that are essential for protein synthesis and overall plant growth.

While ammonium can also be taken up by plants, its uptake is typically slower and less favorable in certain soil conditions, such as those that are acidic or have high levels of moisture, where nitrification (the process that converts ammonium to nitrate) can occur. The gaseous form of nitrogen, N2, is not directly usable by plants and must be converted through biological nitrogen fixation. Nitrite (NO2-) is a transient form in the nitrogen cycle and is generally not utilized by plants for growth.

Understanding the primary form of nitrogen that plants take up helps in managing fertilization strategies and ensuring that crops receive the nutrients they need for optimal growth.