Siklus Nitrogen

Summary

This video explains the nitrogen cycle in detail, starting with nitrogen falling to the ground with rain and being absorbed by plants. Nitrogen is not directly usable by plants, except for those with a symbiotic relationship with Rhizobium bacteria. Through nitrogen fixation, the bacteria convert nitrogen into ammonia, which is then transformed by other bacteria into nitrites and nitrates, usable by plants. As plants and animals die, decomposers break down organic matter, releasing ammonia, which can be converted back into nitrites and nitrates. Eventually, excess nitrates are converted into free nitrogen in the atmosphere, completing the cycle.

Takeaways

• 😀 The nitrogen cycle begins when nitrogen falls to the ground with rain and is absorbed into the soil.
• 😀 Nitrogen cannot be directly absorbed by plants; only plants that form symbiosis with Rhizobium bacteria can take it up.
• 😀 The Rhizobium bacteria in plants with nitrogen-fixing nodules convert nitrogen into ammonia, a process called nitrogen fixation.
• 😀 The ammonia is then converted into nitrite by Nitrosomonas bacteria, and further transformed into nitrate, which is usable by all plants.
• 😀 Plants absorb the nitrate to perform photosynthesis through a process known as assimilation.
• 😀 When plants or animals that consume them die, their bodies are decomposed by fungi and bacteria.
• 😀 The decomposition process turns organic matter into ammonia, a process known as ammonification.
• 😀 The ammonia is then converted back into nitrite and nitrate through nitrification.
• 😀 Nitrate that isn't absorbed by plants for photosynthesis is converted back into free nitrogen by denitrifying bacteria.
• 😀 The free nitrogen in the atmosphere will continue the cycle, repeating over time in a continuous loop.

Q & A

What is the nitrogen cycle?

The nitrogen cycle is the process by which nitrogen moves through the atmosphere, soil, and living organisms in various chemical forms. It includes processes like nitrogen fixation, assimilation, nitrification, and denitrification.

How does nitrogen enter the soil?

Nitrogen enters the soil when it falls with rain, which absorbs the nitrogen from the atmosphere and brings it into the ground.

Why can't plants directly absorb nitrogen from the soil?

Plants cannot directly absorb nitrogen in its gaseous form. It needs to be converted into usable compounds like ammonia, nitrite, and nitrate.

Which plants can absorb nitrogen directly from the soil?

Plants that have a symbiotic relationship with nitrogen-fixing bacteria, such as Rhizobium, or those that have nitrogen-fixing root nodules can absorb nitrogen from the soil.

What is nitrogen fixation?

Nitrogen fixation is the process by which nitrogen in the air is converted into ammonia by nitrogen-fixing bacteria like Rhizobium, making it available for plants.

What happens after nitrogen is fixed into ammonia?

Once nitrogen is fixed into ammonia, it is then converted by bacteria like Nitrosomonas into nitrite, and further into nitrate, which is a form that plants can absorb for their growth.

What role does nitrate play in the nitrogen cycle?

Nitrate is a key form of nitrogen that plants use for photosynthesis. It is absorbed by plants to help with their growth and energy production.

What happens when plants or animals die in the nitrogen cycle?

When plants or animals die, their bodies are broken down by decomposers, like fungi and bacteria, releasing ammonia back into the soil through a process called ammonification.

What is nitrification, and how does it contribute to the nitrogen cycle?

Nitrification is the process by which ammonia is converted into nitrite and then into nitrate by specific bacteria. This makes nitrogen available to plants and continues the nitrogen cycle.

How is nitrogen returned to the atmosphere?

Nitrogen is returned to the atmosphere through the process of denitrification, where nitrate that plants did not absorb is converted back into nitrogen gas by denitrifying bacteria, completing the cycle.