Fertilizers occupy an important position in agricultural production. Agrochemical experts at home and abroad generally believe that fertilizers can increase yield by 40% to 60% when other production factors remain unchanged. As Chinese farmers use more fertilizer to stay at the level of empirical fertilization, the utilization rate of fertilizer is only 30% to 40%, so waste and loss are amazing. This paper introduces the basic knowledge of scientific fertilization and practical techniques that are easy to operate, combined with the reality of agricultural production. Applying this knowledge to guide fertilization can reduce investment, increase output, improve soil fertility, and achieve better economic and social benefits.
There are many Chinese people, and the per capita cultivated land only accounts for 1/3 of the world average; most of the cultivated land has long-term investment, low output, and low potential fertility; the organic matter circulation and reuse rate in cultivated land are not high. Therefore, in order to produce more, it needs more fertilizer input. The main functions are as follows:
1. Provide a large number of high quality agricultural products
A large number of field trials in China have shown that chemical fertilizers can be properly applied, and the energy per kilogram of nutrients can be increased by 8.5 to 9.5 kg, with good economic returns. In 1992, the application rate of chemical fertilizers in China was 29.3 million tons, N:P2O5:K2O=1:0.39:0.14. If 80% of chemical fertilizers were used in food crops, only grain yield increased by 45% of the total. ~50%.
From the energy point of view: 1g fertilizer N (nitrogen) increased production yield of 24g, 4.2kcal per gram of bio-energy, that is, lg fertilizer N can convert bio-energy 100.8kcal. However, the energy consumption of synthesizing 1g of fertilizer N is only 24kcal, which is more than three times. Of course, some farmers have not increased their production after adding fertilizer. There are many reasons, but not the fertilizer itself but the unscientific fertilization.
2, let more organic fertilizer return to the field
The effects of organic fertilizers and fertilizers are consistent and can be transformed into each other. The addition of chemical fertilizers increased yields, not only increased grain but also increased straw. The increase of grain and straw; the relaxation of the tension of feed, fuel and fertilizer is also conducive to the development of animal husbandry, not only satisfying the demand for non-staple food, but also increasing the source of organic fertilizer returning to the field.
In some areas, the soil organic matter content has indeed decreased. The main reason is that farming does not apply fertilizer, less fertilization, or excessive application of nitrogen fertilizer and neglect of organic fertilizer returning to the field.
3. Improve soil nutrient status
According to the positioning test of 30 consecutive fertilizations in different regions for 5-10 years, the results were as follows: 1 application of phosphate fertilizer (P2O5) 3 to 5 kg per season, soil available phosphorus content ratio test The former increase of 40% to 90%; without the application of phosphate fertilizer, it decreased by 23% to 54%. 2 Apply potassium fertilizer (K2O) 5-10 kg per mu, and the soil available potassium increased by about 20% on average. 3 Adding NP (nitrogen phosphorus) or NPK (nitrogen, phosphorus and potassium) fertilizer, the soil organic matter content is small and the impact is small. The area of ​​soils deficient in phosphorus and potassium in China is increasing. The return of organic fertilizers alone cannot meet the demand of crops. The above shows that the application of NP or NPK fertilizers will not cause soil organic matter decline, improve soil nutrient status, and improve soil phosphorus and potassium content. Especially obvious.
We should also see that the unreasonable use of fertilizer does have a negative impact on the soil and the environment. For example, long-term single application of nitrogen fertilizer on the same plot, especially ammonium sulfate, often causes soil compaction and fertility decline; continuous application of physiological acid fertilizer on acidic soil will increase soil acidity and affect normal crop growth; Fertilizer will not only affect the product quality of the chlorine-removing crops; it will also deepen the salinization of the saline-alkali soil; excessive application of nitrogen fertilizer will also cause environmental pollution. These problems can be alleviated or completely avoided by rational use of fertilizer.
In summary, chemical fertilizer plays a big role in China's agricultural production, not only provides a large number of high-quality agricultural and sideline products to the society, but also helps more organic fertilizers return to the fields and improve soil fertility. At the same time, the rational application of chemical fertilizers can also avoid the destruction of soil structure and environmental pollution.
There are many Chinese people, and the per capita cultivated land only accounts for 1/3 of the world average; most of the cultivated land has long-term investment, low output, and low potential fertility; the organic matter circulation and reuse rate in cultivated land are not high. Therefore, in order to produce more, it needs more fertilizer input. The main functions are as follows:
1. Provide a large number of high quality agricultural products
A large number of field trials in China have shown that chemical fertilizers can be properly applied, and the energy per kilogram of nutrients can be increased by 8.5 to 9.5 kg, with good economic returns. In 1992, the application rate of chemical fertilizers in China was 29.3 million tons, N:P2O5:K2O=1:0.39:0.14. If 80% of chemical fertilizers were used in food crops, only grain yield increased by 45% of the total. ~50%.
From the energy point of view: 1g fertilizer N (nitrogen) increased production yield of 24g, 4.2kcal per gram of bio-energy, that is, lg fertilizer N can convert bio-energy 100.8kcal. However, the energy consumption of synthesizing 1g of fertilizer N is only 24kcal, which is more than three times. Of course, some farmers have not increased their production after adding fertilizer. There are many reasons, but not the fertilizer itself but the unscientific fertilization.
2, let more organic fertilizer return to the field
The effects of organic fertilizers and fertilizers are consistent and can be transformed into each other. The addition of chemical fertilizers increased yields, not only increased grain but also increased straw. The increase of grain and straw; the relaxation of the tension of feed, fuel and fertilizer is also conducive to the development of animal husbandry, not only satisfying the demand for non-staple food, but also increasing the source of organic fertilizer returning to the field.
In some areas, the soil organic matter content has indeed decreased. The main reason is that farming does not apply fertilizer, less fertilization, or excessive application of nitrogen fertilizer and neglect of organic fertilizer returning to the field.
3. Improve soil nutrient status
According to the positioning test of 30 consecutive fertilizations in different regions for 5-10 years, the results were as follows: 1 application of phosphate fertilizer (P2O5) 3 to 5 kg per season, soil available phosphorus content ratio test The former increase of 40% to 90%; without the application of phosphate fertilizer, it decreased by 23% to 54%. 2 Apply potassium fertilizer (K2O) 5-10 kg per mu, and the soil available potassium increased by about 20% on average. 3 Adding NP (nitrogen phosphorus) or NPK (nitrogen, phosphorus and potassium) fertilizer, the soil organic matter content is small and the impact is small. The area of ​​soils deficient in phosphorus and potassium in China is increasing. The return of organic fertilizers alone cannot meet the demand of crops. The above shows that the application of NP or NPK fertilizers will not cause soil organic matter decline, improve soil nutrient status, and improve soil phosphorus and potassium content. Especially obvious.
We should also see that the unreasonable use of fertilizer does have a negative impact on the soil and the environment. For example, long-term single application of nitrogen fertilizer on the same plot, especially ammonium sulfate, often causes soil compaction and fertility decline; continuous application of physiological acid fertilizer on acidic soil will increase soil acidity and affect normal crop growth; Fertilizer will not only affect the product quality of the chlorine-removing crops; it will also deepen the salinization of the saline-alkali soil; excessive application of nitrogen fertilizer will also cause environmental pollution. These problems can be alleviated or completely avoided by rational use of fertilizer.
In summary, chemical fertilizer plays a big role in China's agricultural production, not only provides a large number of high-quality agricultural and sideline products to the society, but also helps more organic fertilizers return to the fields and improve soil fertility. At the same time, the rational application of chemical fertilizers can also avoid the destruction of soil structure and environmental pollution.
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