All the grievances suffered by chemical fertilizers are written in this court defense statement
Preface to the defense statement
Chemical fertilizers originated in Europe and are a product of the Industrial Revolution.
In 1800, Britain was the first to recover ammonium sulfate from industrial coking as fertilizer
In 1908, Germany invented the modern synthetic ammonia process, achieving an adequate supply of chemical fertilizers. The application of chemical fertilizers rapidly raised living standards in Europe and made it the center of the world economy.
As the "grain" of grain, chemical fertilizers are the highly efficient nutrients that modern science and technology have brought us, providing agricultural products such as grain, cotton, oilseeds, fruits and vegetables with essential mineral elements including nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, manganese, copper, zinc, boron, molybdenum and chlorine, as well as beneficial elements such as silicon.
Over more than 200 years, while the population has doubled again and again, nutrition levels have risen substantially, human civilization has advanced at an exponential rate, and the bottleneck of traditional agriculture's reliance on the natural restoration of soil fertility has been completely broken through. All of this is thanks to our chemical fertilizers!
In view of the major contributions of chemical fertilizers to human civilization, the inventors of synthetic ammonia technology, Fritz Haber (1918) and Carl Bosch (1931) of Germany, were successively awarded the Nobel Prize in Chemistry.
First: The characteristics and historical achievements of chemical fertilizers
1. Chemical fertilizers come from nature and have high supply efficiency. The main raw material of nitrogen fertilizer comes from the atmosphere, while the raw materials of other chemical fertilizers are mainly minerals. Efficiency is about 1 million times higher than traditional biological nitrogen fixation. Chemical fertilizers have transformed farmland from the long cycle of fertility building plus production into a short cycle of continuous production, greatly improving the output efficiency of farmland.
2. Chemical fertilizers have a high nutrient concentration and strong effect, reducing labor intensity. Chemical fertilizers have freed farmers from heavy labor such as collecting and composting fertilizers, greatly improving farmers' labor productivity.
3. Chemical fertilizers themselves are harmless. Chemical fertilizers have high nutrient content and low impurities. Chemical fertilizers act quickly, helping crops absorb them in time. The nutrients in chemical fertilizers are mainly in inorganic form and do not need microbial transformation and decomposition; after being applied to the soil, they are quickly absorbed by crop roots. For example, after chemical nitrogen fertilizer is applied to the soil, it is generally fully released within 3 to 15 days, and during the vigorous growth stage of plants it can quickly meet crop needs. Chemical fertilizers can also be applied through irrigation and even through foliar spraying, greatly improving the efficiency of crop nutrient uptake.
4. Other phosphorus fertilizers, potassium fertilizers and medium and trace elements are all extracted from minerals, and their basic components are also harmless.
Second: Chemical fertilizers are an important guarantee for eating enough, eating well and eating healthily
According to statistics from the UN Food and Agriculture Organization (FAO), from the 1960s to the 1980s, developing countries increased grain crop yields by 55% to 57% through fertilization, and for China chemical fertilizers are even more significant.
1. Half of China's grain output comes from chemical fertilizers. For more than 2,000 years from the Qin and Han dynasties to the Qing dynasty, China always used traditional agricultural production methods, that is, using crop straw, human and livestock manure and urine, green manure and other methods to build soil fertility, and grain output remained at a relatively low level for a long time. The yield per mu of wheat and rice in China increased only from 106 jin and 80 jin to 195 jin and 291 jin.
In the more than 70 years since the founding of New China, the average yield per mu of wheat in China has reached 700 to 800 jin, and in high-yield areas it has reached 1,500 jin. Among these, the application of chemical fertilizers played a key role. Scientists have proven through research that the yield per unit area of crops without chemical fertilizer and with chemical fertilizer differs by 55% to 65%.
2. Chemical fertilizers have significantly raised the nutritional level of Chinese people. In recent years, the per capita supply of animal protein increased from 1.4 kg in 1961 to 15.5 kg in 2014. The increase in fruit and vegetable production was mainly achieved by raising output through modern production methods (greenhouses, irrigation, chemical fertilizers and pesticides). China's per capita supply of vegetables and fruits has continued to grow, enriching diets while also raising residents' nutritional levels. Chemical fertilizers have greatly enriched the nutrient supply in agricultural production systems, providing the foundation for producing more protein, energy and minerals needed by humans.
3. Chemical fertilizers have improved soil fertility. Cultivated land quality is the basic guarantee of food security. In traditional agriculture, the nutrient content of cultivated land was mainly determined by soil-forming minerals, and the vast majority of soils showed varying degrees of nutrient deficiency. For example, the available phosphorus content of China's soils was relatively low. Through the application of phosphate fertilizer, over the past 30 years China's soil available phosphorus content has risen to 23 mg/kg.
Third: A scientific understanding of several issues in the use of chemical fertilizers
It is easier to understand if chemical fertilizers are compared to the food of food. A series of health problems such as high blood pressure, high blood lipids and high blood sugar caused by unreasonable diet and excess nutrition are problems of the way food is consumed, not problems of the food itself. As with diet, incorrect methods such as excessive application of chemical fertilizers, unreasonable nutrient combinations and extensive application methods will also produce negative effects, but these need scientific analysis, correct understanding and a rational approach.
1. The relationship between chemical fertilizer application and non-point source pollution.
In 2014, the total ammonia nitrogen emissions in the country's wastewater were 2.385 million tons, of which domestic sources emitted 1.381 million tons, agricultural sources emitted 755,000 tons, industrial sources emitted 232,000 tons, and centralized emission sources emitted 17,000 tons.
It can be seen that agricultural sources were lower than domestic source emissions. Agricultural non-point source pollution also includes the loss of chemical fertilizers and the loss of nitrogen and phosphorus nutrients caused by livestock and poultry breeding and aquaculture.
According to research, the contribution of chemical fertilizer nutrient loss to agricultural source nitrogen and phosphorus emissions was 11.2% and 25.7% respectively, which is generally relatively low.
In fact, most of the phosphorus and potassium elements in chemical fertilizers that are not absorbed by the current season's crops will remain in the soil and be used by the next season's crops.
2. The relationship between chemical fertilizer application and air pollution.
Generally speaking, if nitrogen fertilizers applied in agricultural production, such as ammonium-based nitrogen fertilizers including urea, ammonium bicarbonate and diammonium phosphate, enter the soil and are not absorbed and used by crops, part of the nitrogen will be emitted into the atmosphere in the form of reactive nitrogen such as ammonia and nitrogen oxides, causing air pollution.
If deep application with soil covering, split application and the selection of reasonable products are adopted, these losses are very small.
Research shows that at present nitrogen fertilizer contributes about 5% to China's total nitrogen oxide emissions. With changes in fertilization methods, this proportion will gradually decrease further.
3. Soilcompaction is not caused by chemical fertilizers.
When farmers intuitively feel that the soil has become compacted or polluted, they simply attribute it to the effect of chemical fertilizers. In fact, soil compaction is mainly caused by flood irrigation, submerged irrigation and unreasonable tillage.
Rational use of chemical fertilizers, especially combined application with organic fertilizers, can improve soil structure. One point that needs to be emphasized is that the amount of cadmium brought in by industrial and mining extraction and sewage irrigation is far higher than that from fertilizers.
4. Melons not being fragrant and fruits not being sweet is due to unreasonable element combinations, and chemical fertilizers cannot be blamed
"After using chemical fertilizers, melons are not fragrant and fruits are not sweet" is the result of unreasonable application of chemical fertilizers. The appearance, nutrition, internal component composition and storage traits of agricultural products are directly related to chemical fertilizer application! Some fruit growers blindly pursue large fruit and super-high yields, investing large amounts of nitrogen fertilizer and ignoring the coordination of other elements, resulting in very large fruit with a lot of water, while soluble solids and sugar content lag behind, reducing flavor.
In fact, crop quality is related to the proportion of nutrient uptake. If the nutrient structure of chemical fertilizers and the application methods are reasonable, melons and fruits that grow healthily will be more fragrant and sweeter.
In short, at present in China, comprehensively understanding the role of chemical fertilizers and actively and reasonably transforming fertilization methods is a major matter for ensuring food supply and sustainable development.
It is necessary both to change erroneous ideas such as "the more fertilizer applied, the more output increases" and erroneous methods such as "with plenty of water and frequent fertilizer, there is no need to ask anyone," and also not to go to extremes by demonizing chemical fertilizers and thus completely negating them.
Understanding chemical fertilizers scientifically and rationally, applying them correctly and reasonably, and developing and innovating chemical fertilizer products based on modern agriculture are the correct direction.