Acid rain.
There are nitrogen fixing plants, such as legumes, that will add nitrogen to the soil naturally. When these plants die, they release nitrogen into the soil, making it available for other plants.
Soil bacteria are not responsible for fixing nitrogen from the atmosphere. This process is carried out by nitrogen-fixing bacteria like Rhizobium and cyanobacteria.
Nitrogen-fixing bacteria help cycle nitrogen through the ecosystems in a variety of ways. With plants, the nitrogen-fixing bacteria help ensure that nitrogen is cycled back into the soil.
Nitrogen-fixing bacteria in soil convert atmospheric nitrogen (N2) into ammonia (NH3) through a process called nitrogen fixation. This ammonia can then be utilized by plants as a source of nitrogen for growth and development.
Nitrogen-fixing bacteria convert atmospheric nitrogen into a form that plants can use for growth, helping to increase soil fertility.
nitrogen fixing - such as clover or lupins
they help balance the level of nitrogen in the soil and atmosphere.
Soil
The air is about 80% nitrogen- but cannot be used by plants for food. Nitrogen fixing bacteria transform nitrogen in the air to nitrogen in the soil that plants CAN use- resulting in greatly improved plant growth, and more fertile soil.
Bacteria in the soil called nitrogen-fixing bacteria go through a process called nitrogen-fixation which allows nitrogen to enter the atmosphere
they turn the nitogen gas into the nitrates and nitrites essential for the soil
The air is about 80% nitrogen- but cannot be used by plants for food. Nitrogen fixing bacteria transform nitrogen in the air to nitrogen in the soil that plants CAN use- resulting in greatly improved plant growth, and more fertile soil.