How Fertilizers Affect the Nitrogen Cycle

How do fertilizers affect the nitrogen cycle?

Nitrogen is one of the essential elements for plant growth, and the nitrogen cycle plays a vital role in nature. With the rapid development of modern agriculture, the use of fertilizers has become a common means of increasing crop yields. The use of fertilizers, especially nitrogenous fertilizers, is having an important impact on the nitrogen cycle. This article will delve into how fertilizers affect all aspects of the nitrogen cycle and the environmental and agricultural effects they have.

1. Nitrogen cycle basic concept

The nitrogen cycle refers to the cycle of nitrogen between the atmosphere, soil and organisms. This cycle ensures that nitrogen is continuously reused in the ecosystem. Nitrogen enters the soil from the atmosphere and is converted into a form that plants can absorb through the action of some microorganisms. Then, plants absorb nitrogen, animals obtain nitrogen through the food chain, and finally nitrogen is returned to the atmosphere through organic matter decomposition or through denitrification process.

2. Fertilizer effects on nitrogen cycling

Fertilizer is a commonly used supplementary nitrogen source in agricultural production, especially chemical fertilizers (such as urea, ammonia, etc.) have a significant effect on improving crop yield. Excessive or inappropriate use of nitrogen fertilizers can significantly alter the natural balance of the nitrogen cycle.

2.1 provides external nitrogen source

The nitrogen element in fertilizers is mostly present in the form of nitrates (NOelevated) or ammonium salts (NHOSEX), and these forms of nitrogen can be quickly absorbed by plants. A large amount of nitrogen fertilizer will lead to the accumulation of nitrogen in the soil, change the form of nitrogen source in the soil, and affect the activity of microorganisms. For example, nitrogen in the form of ammonium salts inhibits the activity of denitrifying bacteria and reduces the rate of nitrogen transformation in the soil, resulting in the accumulation of nitrogen.

2.2 exacerbates nitrogen loss

Improper use of fertilizers can lead to increased nitrogen loss. When excessive fertilization or fertilizer is applied in an unsuitable environment (such as after heavy rain), nitrogen in the soil is prone to loss, mainly nitrogen oxides (NOx) and nitrate loss. Nitrogen oxides (NOx) affect air quality through atmospheric deposition, while nitrates easily enter groundwater, causing eutrophication and affecting water quality.

3. Fertilizer on soil microbial effects

Microorganisms in the soil play an important role in the nitrogen cycle, and the application of fertilizers directly affects the activity of these microorganisms. Excessive use of nitrogenous fertilizers, in particular, can lead to structural changes in soil microbial communities.

3.1 Microbial Community Alterations

The nitrogen composition of the fertilizer changes the species and quantity of nitrogen-transforming microorganisms in the soil. For example, ammonia nitrogen inhibits the activity of denitrifying bacteria, which in turn reduces the denitrification process of nitrogen, resulting in nitrogen accumulation. Nitrate nitrogen may promote the activity of nitrifying bacteria and accelerate the production and accumulation of nitrate.

3.2 increase greenhouse gas emissions

One negative effect of fertilizer use is the emission of greenhouse gases, especially nitrogen fertilizers. When fertilizers are overapplied, nitrogen is converted to nitrogen oxides (N₂ O), a potent greenhouse gas, through the denitrification process in the soil. Excessive use of nitrogen fertilizer not only affects the stability of the nitrogen cycle, but also exacerbates the trend of global warming.

4. How to reduce fertilizer on nitrogen cycle negative impact?

Although fertilizers have some negative effects on the nitrogen cycle, rational use of fertilizers can reduce these effects. Here are some suggestions:

4.1 moderate fertilization

Excessive fertilization not only wastes fertilizer resources, but also may cause serious negative impact on the environment. Reasonable fertilization, scientific calculation of fertilizer application and avoiding excessive use of nitrogen fertilizer are the keys to ensure the health of nitrogen cycle.

4.2 the use of organic fertilizers and biological fertilizers

Organic fertilizers contain more organic nitrogen, and release nitrogen sources after decomposition, which can slowly release nitrogen and help to maintain the stability of the nitrogen cycle in the soil. The microorganisms in bio-fertilizers can help improve the soil and increase the efficiency of nitrogen conversion, thereby reducing the negative impact on the environment.

4.3 precision fertilization technology

Through soil detection and precision fertilization technology, scientific fertilization can be applied according to crop demand and soil conditions, reduce excessive nitrogen application, and reduce nitrogen loss and greenhouse gas emissions.

5. Conclusion

The effects of fertilizers on the nitrogen cycle are complex and far-reaching. Appropriate fertilization and rational use of different types of fertilizers can effectively promote the reduction of agricultural production and the impact on the ecological environment. With the development of agricultural science and technology, the concept of precision fertilization and sustainable agriculture has gradually become the mainstream. We have reason to believe that in the future, the use of fertilizers will be more efficient and environmentally friendly.