Nitrogen fixation is the process of changing free nitrogen gas into a nitrogen compound that plants can absorb and use. This process can be carried out by nitrogen-fixing bacteria in the soil or by lightning in the atmosphere. Once nitrogen is fixed into compounds such as ammonia or nitrate, plants can then absorb it through their roots and utilize it for growth and development. Nitrogen assimilation is the process by which plants take up and utilize nitrogen from these compounds to build proteins and other essential molecules. Ammonification is the process of converting organic nitrogen into ammonia, which can then be further converted into other nitrogen compounds by soil bacteria. Leaching is the process by which nitrogen compounds are washed away from the soil into water bodies, potentially leading to nutrient pollution.
