Polluting the environment? Destroying the ecology? Fertilizers feel wronged

Since the birth of the first chemical fertilizer, superphosphate, in the UK in 1843, fertilizer, an artificial synthetic product known as "food of food", has played an important role in the development of human society.

After World War II, global food production increased from 630 million tons to 2.59 billion tons in 2018, and the population increased from 2.52 billion in 1950 to 7.58 billion today. The popularization and application of fertilizers was one of the important driving forces.

Image source: Veer Gallery

Fertilizers play an irreplaceable role in agricultural production. However, in recent years, some people have said that fertilizers are useless or harmful, and that fertilizers should be phased out in the future, and that organic agriculture should replace inorganic agriculture. Is this really the case?

First, let us take a closer look at the true nature of fertilizers.

About Fertilizer - Food for Food

Chemical fertilizer is the abbreviation of chemical fertilizer, which is a fertilizer made by chemical and/or physical methods and contains one or several nutrients required for the growth of crops.

Fertilizers are man-made products and have not existed since ancient times. In 1840, the mineral nutrition theory founded by German scientist Liebig laid the theoretical foundation for the rise of the fertilizer industry. The nutrient return theory among Liebig's three major nutrition theories believes that "plants absorb nutrients from the soil, and each harvest must take away certain nutrients from the soil, which reduces the nutrients in the soil and impoverishes the soil. To maintain soil fertility and crop yields, it is necessary to return the nutrients taken away by the plants ." The nutrients such as nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, zinc, and iron absorbed by plants must be replenished artificially, otherwise the deficiency of these irreplaceable nutrients will directly cause a decrease in yield, until the nutrients are exhausted and the yield is completely cut off.

The application of chemical fertilizers is the most cost-effective and simple way of supplementation worldwide . Over the past 100 years, scientists around the world have been constantly exploring to find lower energy consumption, cleaner production technologies and more scientific application methods.

Based on Liebig's theory, scientists began to develop chemical fertilizers. In 1843, the first chemical fertilizer, superphosphate, was born in Britain; in 1861, potash mines were first mined in Germany. However, the application of these fertilizers was very small and did not play a revolutionary role in promoting global food and population. The synthetic ammonia technology from Hable-Bosch was the starting point for truly increasing global food production and changing the agricultural landscape.

Fritz Haber (1868-1934) (Source: Wikipedia)

In 1909, German chemists Haber and Bosch invented a method of synthesizing ammonia using nitrogen from air while studying explosives. The invention and application of this technology marked a huge step for agricultural production to break away from complete dependence on nature and begin to transform towards industrialization. In 1913, Haber and BASF cooperated to establish the first synthetic ammonia production line with an annual output of 30,000 tons.

The site of BASF's first synthetic ammonia reaction tower in Ludwig, Germany (Source: Wikipedia)

Since nitrogen fertilizers were already being mass-produced in 1913, why did the global population only start to grow rapidly after 1950? This is because, on the one hand, the popularization and application of technology takes time, and on the other hand, World War I and World War II disrupted the global promotion of synthetic ammonia technology. After the end of World War II, synthetic ammonia technology began to spread rapidly around the world. It was also at this time that my country began to build synthetic ammonia plants, achieving a leap forward in the development of nitrogen fertilizers.

What would happen if there were no fertilizers? If we turn back the clock to 1900, when fertilizer use was negligible, the world's population was only 1.63 billion. Today, nitrogen fertilizers alone indirectly feed 48% of the world's population. So we have to thank nitrogen fertilizers and fertilizers.

There is something wrong with fertilizers, but it’s not their fault

As people pay more and more attention to environmental pollution, there are opinions that chemical fertilizers will aggravate environmental pollution, are harmful to the human body, and that organic fertilizers are better than chemical fertilizers. This has also caused the impression of chemical fertilizers to decline in people's minds. Although chemical fertilizers do affect the environment, it is not entirely the fault of chemical fertilizers.

For a long time, there have been some serious problems with the application of fertilizers in China's agricultural production . According to research, winter haze in northern China, excessive nitrates in groundwater, eutrophication of surface water bodies, and even soil compaction, acidification, and secondary salinization are all related to fertilizers, especially nitrogen fertilizers. For China's three major grain crops, the utilization rate of nitrogen fertilizers in the season is only 37.8% (statistics from the Ministry of Agriculture in 2018). Wasted nitrogen fertilizers enter water bodies or the atmosphere, increasing the nitrogen content, and a series of problems arise when the nitrogen content exceeds the body capacity.

But we must realize that this is a problem caused by the irrational use of chemical fertilizers, not a problem with chemical fertilizers themselves. Just like the seasonings such as oil, salt, and sugar in our daily lives, these materials themselves are harmless, useful, and beneficial, but if the intake exceeds the standard for a long time, it will cause corresponding symptoms. This is a problem caused by irrational intake of oil, salt, and sugar, but it is not a problem with oil, salt, and sugar themselves. The root of the problem lies in the fact that people do not use and mix oil, salt, and sugar scientifically. Similarly, compared with organic fertilizers, chemical fertilizers are purer, single, and well-known materials, but humans do not use these materials scientifically.

Moreover, it is impossible to completely abandon chemical fertilizers. If only organic fertilizers are used for organic agricultural production, human food production may return to the level of the 19th century, and it will become a pipe dream to feed such a large population in the world.

Decomposing animal manure is a source of organic fertilizer (Source: Wikipedia)

In order to ensure food security and reduce environmental impact, we need to find ways to use fertilizers more efficiently, which has always been the research focus of scientists around the world. Currently, there are two main ways to improve fertilizer utilization:

The first is to transform and upgrade conventional fertilizer products , mainly through biological methods (stable fertilizers), chemical methods (urea-formaldehyde fertilizers), physical methods (coated fertilizers), etc., aiming to delay the impact of the external environment on sensitive and active chemical nutrients and reduce spillover to the external environment. In particular, stable fertilizer technology is becoming the mainstream of new fertilizers in the world because of its natural technical advantages in reducing the possibility of environmental pollution such as ammonia volatilization and nitrous oxide farmland emissions.

The conversion process of nitrogen fertilizer and the mechanism of stable fertilizer technology (Source: Homemade)

The second is to find a more scientific and complementary fertilization method . Based on factors such as the crop's nutrient demand, demand type, demand pattern, and regional environment, explore the rules of matching nutrient demand and supply at each point in crop growth. The ultimate ideal state is that at any point in crop growth, the type and amount of nutrients required are exactly the same as the type and amount of nutrients supplied, no more and no less.

The contribution of fertilizers to human society is self-evident, but we must know that the fault of fertilizers does not come from fertilizers, but from the way people use them. Learning to use fertilizers more scientifically and maximize their effectiveness is the key to achieving green agricultural development and ensuring food security.