How fertilizer use affects the nitrogen cycle
Effect of Chemical Fertilizer Application on Nitrogen Cycle
In modern agriculture, the use of chemical fertilizers has become a common means of increasing crop yields, especially nitrogen fertilizers. Although nitrogen fertilizer is essential for crop growth, it has many negative effects on the nitrogen cycle. This article will discuss in depth the "impact of fertilizer use on the nitrogen cycle" and analyze how it interferes with the natural nitrogen cycle, causes environmental pollution and its long-term effects.
Nitrogen Cycle Basic Concepts
The nitrogen cycle refers to the conversion process of nitrogen in the ecosystem, involving multiple biological and chemical processes. Atmospheric nitrogen (N2) is converted by nitrogen-fixing microorganisms into plant-available ammonia (NH3) or nitrate (NO3-). These nitrogen compounds are taken up by plants and passed through the food chain. Eventually, the nitrogen is converted into nitrogen or other nitrogen-containing compounds by the action of plant and animal death, excreta, and microorganisms, which re-enter the atmosphere or soil.
In the natural environment, nitrogen transformation and recycling is a balanced process. The artificial application of fertilizers, especially those containing nitrogen, tends to upset this balance, leading to many negative consequences.
How doeschemical fertilizer application interfere with the nitrogen cycle?
1. Excessive fertilization caused by excess nitrogen
in agricultural production, excessive application of nitrogen fertilizer is the most common phenomenon. Excessive application of nitrogen fertilizer, especially when the soil is already rich in nitrogen, can lead to excessive nitrogen concentration in the soil. This will not only increase the burden of nitrogen absorption by plants, but also may cause nitrogen loss, such as leaching into groundwater or rivers, or even escape into the atmosphere in gaseous form.
2. Accelerate the volatilization and pollution of nitrogen
excess nitrogen fertilizers can be converted into gaseous ammonia (NH3) or nitrous oxide (N2O) by chemical reactions. Among them, nitrous oxide is a greenhouse gas that has a serious impact on climate change. The volatilization of ammonia not only causes air pollution, but also acidifies water and soil, which further aggravates environmental problems.
3. Destruction of soil microbial communities
nitrogen fertilizer application also affects microbial activity in the soil, especially the function of nitrogen-fixing bacteria. Excess nitrogen fertilizer inhibits natural nitrogen-fixing microorganisms in the soil, reduces their activity, and thus reduces the efficiency of the natural nitrogen cycle. This inhibitory effect means that the dependence of farmland on nitrogen fertilizer will increase, which is not conducive to the natural balance of nitrogen in the ecosystem.
Use of chemical fertilizers leads to environmental pollution
1. Water pollution
after the application of chemical fertilizers, excessive nitrogen compounds can be lost to rivers, lakes and groundwater through rain or irrigation water, resulting in eutrophication of water bodies. High nitrogen content in water promotes the rapid growth of algae, leads to the phenomenon of water bloom, and eventually leads to the deterioration of water quality, affecting the survival of aquatic organisms. Eutrophication not only destroys the water ecosystem, but also increases the cost of water treatment.
2. Greenhouse gas emissions
excessive use of nitrogen fertilizers increases the emission of nitrous oxide in the atmosphere. N2O is a greenhouse gas whose greenhouse effect is 298 times that of carbon dioxide and contributes significantly to global warming. Therefore, fertilizer use not only directly affects the nitrogen cycle, but also indirectly affects the ecological environment through climate change.
How to reduce the impact of fertilizers on the nitrogen cycle?
1. Scientific fertilization
in order to reduce the effect of chemical fertilizer on nitrogen cycle, agricultural producers should adopt scientific fertilization methods and avoid blind application of nitrogen fertilizer. Through the soil test to accurately measure the nitrogen content in the soil, reasonable adjustment of fertilization. Phased fertilization can avoid excessive nitrogen fertilizer into the soil at one time.
2. Adopting organic fertilizers and eco-agricultural methods
the use of organic fertilizers can increase the organic matter content of the soil, improve the structure and microbial activity of the soil, and promote the natural transformation process of nitrogen. Combining agro-ecological methods, such as crop rotation, intercropping and cover crops, can also reduce the amount of nitrogen fertilizer used and restore the natural nitrogen cycle in the soil.
Conclusion
The use of chemical fertilizers has a significant impact on the nitrogen cycle, especially excessive application of nitrogen fertilizer will lead to excess nitrogen, volatilization, pollution and imbalance of soil microorganisms, thus destroying the normal function of the ecosystem. In order to reduce these negative effects, more scientific and sustainable agricultural fertilization methods must be adopted to ensure the coordinated development of agricultural production and environmental protection.