In recent years, the society has talked about the abnormal phenomenon of "changing" the discoloration, and even the "we hate the chemical" such as ignorant speech, as an important petrochemical products, fertilizer, in the pursuit of high quality of life today, is subject to criticism.Can modern agriculture leave fertilizer?Farmland non-point source pollution, air pollution, fertilizer to bear the primary responsibility?Melon is not fragrant, fruit is not sweet is caused by fertilizer?
China Agricultural University Resources, Environment and Food Security Research Center Director Professor Zhang Fu lock entitled "Fertilizer - industrial revolution results of modern agriculture support" heavy article, elaborated why the farmland is inseparable from the fertilizer? Eat, eat, health, fertilizer ye keep? At the same time, it clarified the air pollution: nitrogen fertilizer is not the biggest contributor; soil compaction: unreasonable farming caused; low quality of agricultural products: unreasonable fertilization affect the view.
In the public on the misunderstanding of chemical fertilizers and doubts, and even the demonization of fertilizers in front of Professor Zhang Fu lock pointed out: high blood pressure, high blood lipids, high blood sugar and a series of health problems, food intake is a problem, not the food itself is a problem. And the same diet, the application of excessive fertilizer, nutrients with unreasonable, extensive use of the wrong way will have a negative impact, but the need for scientific analysis, a correct understanding, rational treatment. Professor Zhang Fu lock pointed out that the transformation of fertilizer production and application, is to ensure food supply and sustainable development of the event. It is necessary to change the "more fertilizer and more yield" "water fat do not ask people" and other misconceptions, can not demonize the fertilizer. Scientific rational understanding of chemical fertilizers, the correct and rational use of fertilizers, based on modern agricultural innovative products and services, is the right direction.
Why is farmland inseparable from fertilizer?
Fertilizer from nature, the supply of high efficiency. The main raw material of nitrogen fertilizer from the atmosphere, other chemical raw materials are mainly minerals. Nitrogen fertilizer production and biological nitrogen fixation mechanism similar to high temperature, high pressure and catalysis, the inert nitrogen in the atmosphere can be used as a crop can be active nitrogen (ammonium salt, nitrate). In a 10 hectares of land on the establishment of the ammonia plant, the daily production of 3,000 tons of nitrogen, one year to meet the 10 million mu of farmland to maintain the yield of 400 to 500 kg per mu, than the traditional biological nitrogen fixation efficiency increased by about 100 million times. Fertilizers have allowed farmland to shift from a long period of fertilizers to production to a short cycle of continuous production, which has greatly improved farmland output efficiency.
Fertilizer nutrient concentration is high, fresh, reducing the labor intensity. Fertilizer nutrient content is generally more than 40%, more than 10 times the traditional organic fertilizer. Urea nitrogen 46%, to meet the acres of farmland 10 kg of nitrogen supply, only about 25 kg of urea, a labor force hand half a day to complete. The traditional agricultural collection, pile retting, transportation, application of organic fertilizer, many people need to spend a few months. Fertilizers greatly improve labor productivity.
High fertilizer fertilizer, conducive to timely absorption of crops. Fertilizer nutrients are mainly inorganic, into the soil will be quickly absorbed by the crop roots. Nitrogen fertilizer applied to the soil after 3 to 15 days will be completely released in the plant growth stage can quickly meet the needs of crops. Fertilizers can also be applied by irrigation, even through foliar spraying, which greatly improves the nutrient uptake efficiency of the crop.
Fertilizer itself is harmless. Fertilizer high nutrient content, low impurity. For example, urea contains 46% nitrogen, nitrogen is the crop of nutrients needed, the rest are mainly CO2, applied to the soil will be released again after the return to the atmosphere, is harmless. In addition, urea also contains about 1% water and about 1% biuret. Biodegradation is limited to 1.5% or less, and is decomposed in the soil and is used by crops and microbes. Other phosphate fertilizer, potash and trace elements are extracted from the minerals, the basic ingredients are also harmless.
Eat, eat, health, fertilizer ye keep?
The first green revolution in the 1960s was an important milestone in the history of human development, and the supply of agricultural products was improved through high-yielding varieties, irrigation, mechanization and extensive use of fertilizers. According to the Food and Agriculture Organization of the United Nations (FAO), developing countries increased their yields by 55% to 57% by fertilization in the 1960s to the 1980s. And fertilizer for China, the significance is more significant.
Half of China's grain output comes from fertilizers. Before the founding of new China, China follows the traditional agricultural production methods, that is, the use of crop stalks, human and animal waste, green manure and other fertility, food production is low. Qin Han to the Qing Dynasty more than 2,000 years, China's wheat yield per mu from only 53 kg to 97.5 kg. Since the founding of new China more than 70 years, wheat yield reached 350 ~ 400 kg, high yield area reached 750 kg. Among them, fertilizer application has played a key role. Scientists have shown that the yield of non-chemical fertilizers and fertilizers is 55% to 65%.
Fertilizer significantly improved the nutritional level of Chinese people. In recent years, China's per capita vegetable and fruit supply continued to grow, while rich recipes, but also improve the nutritional level of residents. Per capita animal protein supply increased from 1.4 kg in 1961 to 15.5 kg in 2014. Fruit and vegetable production, mainly through modern means of production to improve output. The growth of meat products and dairy products comes from the increase in feed supply, while feed production also relies on the application of fertilizers. Fertilizers provide the basis for the production of more protein, energy, and minerals needed by humans.
Fertilizers improve soil fertility. The quality of cultivated land is the basic guarantee of food security. The nutrient content of traditional agricultural cultivated land is mainly determined by the formation of minerals, the vast majority of soils have varying degrees of nutrient deficiency. For example, soil available phosphorus content is relatively low. According to the last 80 years of the last soil survey data, the average content of only 7.4 mg / kg. Through the application of phosphate fertilizer, the soil available phosphorus content in China increased to 23 mg / kg in the past 30 years. Fertilizer application can also increase the crop biomass, improve the surface coverage, reduce soil erosion. The soil itself is also carbon sinks, which can store greenhouse gases and reduce the negative effects of industrialization. By increasing crop yields, land space can also be provided for urban construction, industrial and commercial development.
Air pollution: nitrogen is not the biggest contributor
Agricultural use of nitrogen fertilizer, such as urea, ammonium bicarbonate and diammonium and other ammonium nitrogen into the soil, if not absorbed by the crop, part of the nitrogen will be ammonia and nitrogen oxides and other active nitrogen emissions, causing the atmosphere Pollution. If the use of deep soil, sub-application, the choice of reasonable products, these losses are very small. Studies have shown that the current nitrogen fertilizer contribution to China's total nitrogen oxides emissions of about 5%.
Soil compaction: caused by unreasonable farming
Farmers intuitively feel the soil compaction, pollution, and simply attributed to the chemical fertilizer caused. In fact, soil compaction is mainly flood irrigation, flood irrigation, irrational farming caused by. Reasonable application of chemical fertilizers, especially with organic fertilizers, can improve the soil structure. In addition, only ammonium phosphate in the fertilizer will bring a certain amount of heavy metals, heavy soil pollution on the soil is very small. China's phosphate rock is very low, according to the current fertilizer (50 kg / mu, according to the average cadmium 10 mg / kg), the annual intake of cadmium is only 0.5 grams / mu. While the amount of cadmium in mining and sewage irrigation is much higher than that of fertilizer.
Low quality of agricultural products: unreasonable fertilization effect
People often said, "with the fertilizer, melon is not fragrant, fruit is not sweet," is actually part of the fruit of the blind pursuit of large fruit and super high yield, a large number of nitrogen fertilizer, ignoring the other elements, resulting in a lot of fruit, Soluble solids, sugar but not keep up, the flavor is reduced. Fertilizer nutrient structure, the application of reasonable and healthy growth of fruit, fruit is more fragrant, melon more sweet.
