Plants get nitrogen for making proteins through the process of nitrogen fixation, which involves converting atmospheric nitrogen into a form that plants can use. This process occurs naturally through the action of certain bacteria in the soil, which convert nitrogen gas (N2) into ammonia (NH3) or nitrate (NO3-) ions.

Factors Affecting Nitrogen Fixation

Several factors can affect the rate of nitrogen fixation in soil, including the presence of certain bacteria, the pH level of the soil, and the availability of other nutrients like phosphorus and potassium.

Role of Legumes

One important way that plants obtain nitrogen is through the use of legumes, which are plants that have a special relationship with nitrogen-fixing bacteria. These bacteria live in nodules on the roots of legumes, where they convert atmospheric nitrogen into a usable form for the plant. When the legume plant dies, the nitrogen that has been fixed in the soil is available for other plants to use.

Other Ways to Obtain Nitrogen

In addition to nitrogen fixation, plants can also obtain nitrogen through the use of fertilizers that contain nitrogen compounds like urea or ammonium nitrate. However, excessive use of nitrogen fertilizers can lead to environmental problems like eutrophication, which can harm aquatic ecosystems.

Conclusion

In summary, plants obtain nitrogen for making proteins through the process of nitrogen fixation, which involves converting atmospheric nitrogen into a usable form. This process occurs naturally in the soil through the action of certain bacteria, and can also be facilitated through the use of legumes. Other sources of nitrogen include fertilizers, but care must be taken to avoid overuse and environmental damage.

Plant get nitrogen naturally as well as artificially.
1) by the bacterium rhizobium that is commonly present in rot nodules of leguminous plant that can take atmospheric nitrogen and convert it into soluble form like nutrates.
2) and artificially by spreading manure & fertilizers that contain nutrients such as nitrogen in the fields.