Nitrogen cycle: A natural process that sustains the continuous life on Earth.

Author: Zhu Zhaoliang
Publisher:
Publish Date: 2002-07-01
Features: It is often said that nitrogen, phosphorus, and potassium are the three essential nutrients for plants; while protein, carbohydrates, and fat are the three major nutrients for humans and animals. Nitrogen is one of the main constituent elements of protein. Although nearly a quarter of the air is nitrogen gas, it cannot be directly utilized by plants and must be converted into NH4 through chemical engineering or soil nitrogen-fixing microorganisms N2 before absorption. Humans and animals cannot utilize NH4 and can only become nutrients for them after plants convert it into protein and amino acids. After chemical fertilizer nitrogen enters farmland, part of it undergoes various transformation processes driven by microorganisms along with nitrogen from entering soil organic matter and animal and human excrement, forming various nitrogen-containing gases. This book covers topics such as nitrogen, the layers of nature and the nitrogen cycle, how nitrogen cycles in nature—nitrogen transformation and migration, the geochemical distribution of nitrogen in nature, and the exchange of nitrogen between the atmosphere, land, and oceans.