Question

Atmospheric nitrogen isn't directly usable by plants. What types of fixation help create addtional usable nitrogen in soil? a) Industrial fixation. b) Atmospheric fixation. c) Mineral fixation. d) Biological fixation.

Answer 1

The types of fixation contributing to usable nitrogen in soil include industrial, atmospheric, and biological fixation, with the latter being the process where microorganisms convert atmospheric nitrogen into ammonia. Biological fixation, conducted by bacteria like rhizobia in legume root nodules, is directly beneficial to plant growth and is the correct answer to the student's question.

Step-by-step explanation:

Atmospheric nitrogen isn't directly usable by plants; it needs to be converted into a form that plants can use. Types of fixation that help create additional usable nitrogen in soil include:

• Industrial fixation, which is the man-made process of converting nitrogen gas into ammonia using the Haber-Bosch process.
• Atmospheric fixation occurs when lightning breaks nitrogen molecules, allowing them to combine with oxygen to form nitrogen oxides, which are then deposited into the soil by rainfall.
• Biological fixation, primarily the process by which certain microbes, such as rhizobia in the root nodules of legumes, convert atmospheric nitrogen into ammonia that plants can incorporate into proteins.

The correct answer to the question is d) Biological fixation. This process is crucial for agriculture as it contributes significantly to the nitrogen used in farming, improving agricultural production by supplying the essential nutrient for nucleotide and protein formation in plants.

Answer 2

Biological and industrial nitrogen fixation are essential methods in converting atmospheric nitrogen into forms that plants can use, mainly as ammonia for biological processes and plant growth.

Step-by-step explanation:

The types of nitrogen fixation that help create additional usable nitrogen in soil include biological fixation, which is the process where organisms, particularly symbiotic bacteria associated with legume plants, convert atmospheric nitrogen into ammonia (NH3). This is a key part of the nitrogen cycle and is critical for agricultural productivity as plants use this fixed nitrogen to form nucleotides and proteins necessary for their growth.

Industrial fixation also contributes to the availability of usable nitrogen through the Haber-Bosch process, which synthesizes ammonia from nitrogen and hydrogen gases under high temperatures and pressures. Atmospheric fixation occurs during lightning strikes, which produce enough energy to naturally convert nitrogen gas into nitrates, though this accounts for a smaller portion of nitrogen fixation.