Rational use of chemical fertilizers has both safety and quality problems. Rational use of fertilizer refers to the establishment of plant nutrition, based on crops, soil, fertilizer traits to determine the amount of fertilizer used and rational use. Pollution-free agricultural products highlight the problem of pesticide safety. The key to the production of high-quality agricultural products lies in the rational use of chemical fertilizers.
The so-called rational fertilization is to select fertilizers for plant nutrient characteristics, soil characteristics, crop growth period, adhere to the combination of organic and inorganic fertilizers; adhere to soil, due to rational fertilization of crops, adhere to lack of supplements, balanced fertilization; determine reasonable Rotation of fertilization system, rational allocation of nutrients; using reasonable fertilization techniques to improve fertilizer utilization.
Select fertilizers for soil properties.
The soils in north and south of China vary greatly. Red soil, brick red soil, yellow soil, yellow brown soil and brown soil in the south are acidic or slightly acidic. Phosphate fertilizer should use alkaline calcium and magnesium fertilizer; northern soil chernoze, chestnut soil, Gray lime soil, cinnamon soil, etc. are mostly alkaline, phosphate fertilizer should use acidic calcium superphosphate; greenhouses and old vegetable fields that have been fertilized for many years are gradually acidified, and calcium and magnesium are deficient. Phosphate fertilizer should use alkaline calcium magnesium phosphate fertilizer and phosphorus. Mineral powder, etc., can not only adjust the acidity of the soil, but also supply calcium and magnesium elements; alkaline soils and saline soils with salinization characteristics, especially coastal saline soils, easy to apply phosphogypsum, potassium sulfate should be selected.
Select fertilizer for plant nutrient properties
Different plant types and varieties have different nutrient requirements. The same plant varieties have different nutrient requirements and proportions in different growth stages and different yield levels; different plants have special responses to nutrient types; different plants have different nutrient absorption and utilization capacities, and select fertilizer varieties. Scientific selection should be based on the nutritional characteristics of the crop. According to the study, there is no significant difference in the effects of ammonium nitrogen fertilizer and nitrate nitrogen fertilizer on nitrate content in vegetables.
Generally, vegetables are nitrogen-nitrogen crops. Nitrogen fertilizers should be selected from ammonium nitrate and calcium nitrate. Bulb vegetables require a large amount of sulfur. Fertilizers containing more sulfur, such as superphosphate, magnesium sulfate and potassium sulfate, should be used. Etc.; Brassica vegetables need a large amount of boron, it is better to use boric acid, borax, etc. containing more boron; fresh edible melons such as watermelon, melon and tea are sensitive to chlorine toxicity, and ammonium chloride should not be used. Potassium chloride and other chlorinated fertilizers; Chinese cabbage, tomato and other prone to calcium deficiency symptoms (dry heart, rot), it is advisable to use calcium superphosphate and calcium nitrate containing more effective calcium; fruit, tea needs a lot of organic fat.
Select fertilizer for crop growth period
Different periods of crop growth have different absorption of fertilizers, so different fertilizers need to be selected for different growth periods. The fertilizer is selected from the neutral high-concentration compound fertilizer, and the fertilizer is generally selected as the special fertilizer; the base fertilizer can be selected from the low-concentration fertilizer, and the high-concentration compound fertilizer can also be used; the high-concentration quick-acting fertilizer such as urea and diammonium phosphate is used for the top dressing. , potassium dihydrogen phosphate, etc.; fertigation and foliar spray fertilizer, the use of high concentration, easy to dissolve, less residue of fertilizers such as urea, ammonium nitrate, potassium dihydrogen phosphate and a wide variety of foliar fertilizer.
Organic fertilizer combined with chemical fertilizer
The addition of organic fertilizer is even more important for the development of sustainable agriculture and pollution-free agricultural production. Studies have shown that the combination of organic fertilizer and chemical fertilizer is beneficial to the renewal of soil organic matter, stimulate the activity of the original humus, increase the substitution of soil cations, improve the activity of soil enzymes, and increase the nutrient absorption and buffering performance of crops. And the stress resistance of crops; it is conducive to the coordination of nitrogen balance and stability, long-term effect, improve the utilization of nitrogen, phosphorus and potassium fertilizers, alleviate the imbalance of fertilization ratio; help improve crop quality, improve the content of nutrients such as protein and amino acids, and reduce vegetables. Nitrate and nitrite content in fruits and fruits.
Choose a reasonable fertilization method
The nitrate content in vegetables is related to the type, variety and different parts of vegetables, and is related to fertilization techniques and environmental conditions. In terms of breeding, it is meaningful to use low nitrate content as one of the breeding objectives; in terms of fertilization techniques and environmental conditions, the nitrate content in vegetables is closely related to the concentration of nitrogen in the soil and the type of nitrogen. The higher the concentration, the higher the nitrate content in the vegetables, especially in the later stages. Therefore, the application of nitrogen fertilizer should be early, and should not be too much.
Development of special, compound, special fertilizer
Because high-quality agricultural products have different requirements for soil and fertilizer, special fertilizers are needed. For example, the production of garlic requires a fertilizer with a high sulfur content. The production of beer barley requires a reduction in the proportion of nitrogen fertilizer, and the ratio of producing 500 kilograms of rice to 900 kilograms of rice is different.
Japanese fruit trees should be fertilized for leaf color diagnosis and symptomatic supplement fertilizer. In addition to nitrogen, phosphorus and potassium fertilizers, there are various calcium, magnesium, sulfur fertilizers, trace element fertilizers, and foliar fertilizers. The specialization, compounding and diversification of fertilizers are the development trend of fertilizers in the world.
In addition, special fertilizers can be produced for human nutrition needs. According to a survey by the Chinese Academy of Sciences, the Ministry of Health, the Ministry of Geology and the National Environmental Protection Agency, some parts of China's 22 provinces and cities and most of them lack selenium, affecting the health of 250 million people. Studies have shown that the application of selenium-containing organic compound fertilizer can increase the content of selenium in food. Applying selenium-containing organic compound fertilizer on cauliflower, the selenium content in cauliflower can reach 0.149mg/kg, which is 75 times that of common cauliflower containing 0.002mg/kg of selenium.
Improve fertilizer use efficiency
China now uses 42 million tons of fertilizer, accounting for about 30% of the world's total. However, the current fertilizer utilization rate is only about 35%, which is far from the world's 45% level. Therefore, it is particularly important to improve China's existing fertilizer production structure, improve fertilization structure, improve fertilization methods, rational use of chemical fertilizers, and increase fertilizer utilization rate, especially in the current oil crisis.
The so-called rational fertilization is to select fertilizers for plant nutrient characteristics, soil characteristics, crop growth period, adhere to the combination of organic and inorganic fertilizers; adhere to soil, due to rational fertilization of crops, adhere to lack of supplements, balanced fertilization; determine reasonable Rotation of fertilization system, rational allocation of nutrients; using reasonable fertilization techniques to improve fertilizer utilization.
Select fertilizers for soil properties.
The soils in north and south of China vary greatly. Red soil, brick red soil, yellow soil, yellow brown soil and brown soil in the south are acidic or slightly acidic. Phosphate fertilizer should use alkaline calcium and magnesium fertilizer; northern soil chernoze, chestnut soil, Gray lime soil, cinnamon soil, etc. are mostly alkaline, phosphate fertilizer should use acidic calcium superphosphate; greenhouses and old vegetable fields that have been fertilized for many years are gradually acidified, and calcium and magnesium are deficient. Phosphate fertilizer should use alkaline calcium magnesium phosphate fertilizer and phosphorus. Mineral powder, etc., can not only adjust the acidity of the soil, but also supply calcium and magnesium elements; alkaline soils and saline soils with salinization characteristics, especially coastal saline soils, easy to apply phosphogypsum, potassium sulfate should be selected.
Select fertilizer for plant nutrient properties
Different plant types and varieties have different nutrient requirements. The same plant varieties have different nutrient requirements and proportions in different growth stages and different yield levels; different plants have special responses to nutrient types; different plants have different nutrient absorption and utilization capacities, and select fertilizer varieties. Scientific selection should be based on the nutritional characteristics of the crop. According to the study, there is no significant difference in the effects of ammonium nitrogen fertilizer and nitrate nitrogen fertilizer on nitrate content in vegetables.
Generally, vegetables are nitrogen-nitrogen crops. Nitrogen fertilizers should be selected from ammonium nitrate and calcium nitrate. Bulb vegetables require a large amount of sulfur. Fertilizers containing more sulfur, such as superphosphate, magnesium sulfate and potassium sulfate, should be used. Etc.; Brassica vegetables need a large amount of boron, it is better to use boric acid, borax, etc. containing more boron; fresh edible melons such as watermelon, melon and tea are sensitive to chlorine toxicity, and ammonium chloride should not be used. Potassium chloride and other chlorinated fertilizers; Chinese cabbage, tomato and other prone to calcium deficiency symptoms (dry heart, rot), it is advisable to use calcium superphosphate and calcium nitrate containing more effective calcium; fruit, tea needs a lot of organic fat.
Select fertilizer for crop growth period
Different periods of crop growth have different absorption of fertilizers, so different fertilizers need to be selected for different growth periods. The fertilizer is selected from the neutral high-concentration compound fertilizer, and the fertilizer is generally selected as the special fertilizer; the base fertilizer can be selected from the low-concentration fertilizer, and the high-concentration compound fertilizer can also be used; the high-concentration quick-acting fertilizer such as urea and diammonium phosphate is used for the top dressing. , potassium dihydrogen phosphate, etc.; fertigation and foliar spray fertilizer, the use of high concentration, easy to dissolve, less residue of fertilizers such as urea, ammonium nitrate, potassium dihydrogen phosphate and a wide variety of foliar fertilizer.
Organic fertilizer combined with chemical fertilizer
The addition of organic fertilizer is even more important for the development of sustainable agriculture and pollution-free agricultural production. Studies have shown that the combination of organic fertilizer and chemical fertilizer is beneficial to the renewal of soil organic matter, stimulate the activity of the original humus, increase the substitution of soil cations, improve the activity of soil enzymes, and increase the nutrient absorption and buffering performance of crops. And the stress resistance of crops; it is conducive to the coordination of nitrogen balance and stability, long-term effect, improve the utilization of nitrogen, phosphorus and potassium fertilizers, alleviate the imbalance of fertilization ratio; help improve crop quality, improve the content of nutrients such as protein and amino acids, and reduce vegetables. Nitrate and nitrite content in fruits and fruits.
Choose a reasonable fertilization method
The nitrate content in vegetables is related to the type, variety and different parts of vegetables, and is related to fertilization techniques and environmental conditions. In terms of breeding, it is meaningful to use low nitrate content as one of the breeding objectives; in terms of fertilization techniques and environmental conditions, the nitrate content in vegetables is closely related to the concentration of nitrogen in the soil and the type of nitrogen. The higher the concentration, the higher the nitrate content in the vegetables, especially in the later stages. Therefore, the application of nitrogen fertilizer should be early, and should not be too much.
Development of special, compound, special fertilizer
Because high-quality agricultural products have different requirements for soil and fertilizer, special fertilizers are needed. For example, the production of garlic requires a fertilizer with a high sulfur content. The production of beer barley requires a reduction in the proportion of nitrogen fertilizer, and the ratio of producing 500 kilograms of rice to 900 kilograms of rice is different.
Japanese fruit trees should be fertilized for leaf color diagnosis and symptomatic supplement fertilizer. In addition to nitrogen, phosphorus and potassium fertilizers, there are various calcium, magnesium, sulfur fertilizers, trace element fertilizers, and foliar fertilizers. The specialization, compounding and diversification of fertilizers are the development trend of fertilizers in the world.
In addition, special fertilizers can be produced for human nutrition needs. According to a survey by the Chinese Academy of Sciences, the Ministry of Health, the Ministry of Geology and the National Environmental Protection Agency, some parts of China's 22 provinces and cities and most of them lack selenium, affecting the health of 250 million people. Studies have shown that the application of selenium-containing organic compound fertilizer can increase the content of selenium in food. Applying selenium-containing organic compound fertilizer on cauliflower, the selenium content in cauliflower can reach 0.149mg/kg, which is 75 times that of common cauliflower containing 0.002mg/kg of selenium.
Improve fertilizer use efficiency
China now uses 42 million tons of fertilizer, accounting for about 30% of the world's total. However, the current fertilizer utilization rate is only about 35%, which is far from the world's 45% level. Therefore, it is particularly important to improve China's existing fertilizer production structure, improve fertilization structure, improve fertilization methods, rational use of chemical fertilizers, and increase fertilizer utilization rate, especially in the current oil crisis.
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