Non-polluted vegetables refer to the content of various pollutants and harmful substances such as pesticide residues, heavy metals and nitrates in vegetables, which are controlled within the limits prescribed by the state, and vegetables that are not harmful to human health after consumption. What technical measures should be taken to produce pollution-free vegetables, especially how to apply scientific fertilization. The following is a brief description from four aspects:
First, the principle of fertilization of pollution-free vegetables is mainly organic fertilizer, supplemented by other fertilizers; mainly multi-component fertilizers, supplemented by single-factor fertilizers; mainly based on fertilizer, supplemented by topdressing. Try to limit the application of chemical fertilizers, and if necessary, a limited amount of selective application of some fertilizers.
1. In accordance with the national standard "Requirements for the safety and quality of agricultural products without pollution" (GB18406.1-2001) as the principle. Fertilization should not cause environmental pollution, and take into account high yield and high efficiency.
2. The principle of organic fertilizer and supplemented by chemical fertilizer. Pay attention to the application of high-quality organic fertilizer, rationally apply chemical fertilizer, the ratio of organic nitrogen to inorganic nitrogen is not less than 1:1, combined with land and land.
3. The principle of balanced fertilization. Based on the results of soil nutrient determination and the fertilizer requirement of vegetables, the application amount of fertilizer was determined according to the requirements of balanced fertilization. Although there are corresponding standards in all localities, the following principles are generally not exceeded: the maximum inorganic nitrogen nutrient application limit is 225 kg/ha, while the inorganic phosphate fertilizer and potassium fertilizer application rate are determined according to soil fertility conditions to maintain soil nutrient balance. quasi. It is forbidden to use chlorinated fertilizer on the avoidance of chlorine vegetables; no nitrate nitrogen fertilizer should be applied to leafy vegetables and root vegetables.
4, the principle of nutritional diagnosis and topdressing. According to the nutritional characteristics of vegetable growth and development, and the soil and plant nutrition diagnosis, the fertilizer is applied to meet the nutrient requirements of vegetables. For vegetables harvested at one time, especially leafy vegetables, nitrogen fertilizer should not be applied within 20 days before harvesting; for vegetables with continuous results, the number of top dressing should not exceed 4-5 times.
Second, pollution-free vegetable fertilization types In the production of pollution-free vegetables, the types and types of fertilizers allowed are:
1. High quality organic fertilizer. Such as compost, manure, biogas fertilizer, green manure, crop straw, mud fertilizer, cake fertilizer and so on. It should be fully decomposed before application.
2, biological fertilizer. These include humic acid fertilizers, rhizobial fertilizers, phosphorus bacterial fertilizers, and compound microbial fertilizers.
3. Inorganic fertilizers. Such as ammonium sulfate, urea, superphosphate, potassium sulfate and other NPK fertilizers that contain neither chlorine nor nitrate nitrogen, and vegetable fertilizers produced everywhere.
4. Trace element fertilizer. That is, copper, iron, boron, zinc, manganese, molybdenum and other trace elements and beneficial elements are mainly formulated fertilizers.
5. Other fertilizers. Such as bone meal, amino acid residue, livestock processing waste, sugar factory waste and so on.
Third, comprehensive implementation of soil testing formula balanced fertilization
In order to reduce pollution and give full play to fertilizer efficiency, balanced fertilization of soil testing formula should be implemented, that is, according to the nutritional and physiological characteristics of vegetables, the law of fertilizer absorption, soil fertility performance and fertilizer effect, the appropriateness of organic fertilizer, nitrogen, phosphorus, potassium and trace element fertilizers should be determined. The amount and proportion and the corresponding fertilization technology, to achieve symptomatic formula, symptomatic application. The specifics should include the variety and amount of fertilizer; the proportion of base fertilizer and top dressing; the number and period of top dressing; and the fertilization method used according to the characteristics of the fertilizer. Formulated fertilization is the basic fertilization technique for the production of pollution-free vegetables.
4. Precautions in fertilization of pollution-free vegetables
1. Organic fertilizers such as human excrement and manure should be fully fermented and decomposed, and rinsed with water after topdressing.
2, fertilizer, vegetable special fertilizer to deep application, early application, deep application can reduce nutrient volatilization, extend fertilizer time, improve fertilizer utilization. Early application is beneficial to early plant growth, prolonging fertilizer efficiency and reducing the accumulation of toxic substances such as nitrate. Generally, ammonium nitrogen is applied to the soil layer below 6 cm, urea is applied to the soil layer below 10 cm, phosphorus and potassium fertilizer is applied to the soil layer below 15 cm, and the special fertilizer for vegetables is applied to the soil layer below 15 cm.
3, according to the type of vegetables and cultivation conditions flexible fertilization, different types of vegetables, the accumulation of nitrates vary greatly, generally leafy vegetables are higher than melons, melons and vegetables are higher than fruit. In addition, the nitrate content of the same vegetable in different climatic conditions is also different, generally under high temperature and strong light, nitrate accumulation is less. Conversely, under low temperature and low light, nitrate is accumulated in large amounts. In the process of fertilization, the type of vegetables, cultivation season and climatic conditions should be considered, and the reasonable amount of chemical fertilizer should be mastered to ensure that the nitrate content is within the prescribed range of pollution-free vegetables.
First, the principle of fertilization of pollution-free vegetables is mainly organic fertilizer, supplemented by other fertilizers; mainly multi-component fertilizers, supplemented by single-factor fertilizers; mainly based on fertilizer, supplemented by topdressing. Try to limit the application of chemical fertilizers, and if necessary, a limited amount of selective application of some fertilizers.
1. In accordance with the national standard "Requirements for the safety and quality of agricultural products without pollution" (GB18406.1-2001) as the principle. Fertilization should not cause environmental pollution, and take into account high yield and high efficiency.
2. The principle of organic fertilizer and supplemented by chemical fertilizer. Pay attention to the application of high-quality organic fertilizer, rationally apply chemical fertilizer, the ratio of organic nitrogen to inorganic nitrogen is not less than 1:1, combined with land and land.
3. The principle of balanced fertilization. Based on the results of soil nutrient determination and the fertilizer requirement of vegetables, the application amount of fertilizer was determined according to the requirements of balanced fertilization. Although there are corresponding standards in all localities, the following principles are generally not exceeded: the maximum inorganic nitrogen nutrient application limit is 225 kg/ha, while the inorganic phosphate fertilizer and potassium fertilizer application rate are determined according to soil fertility conditions to maintain soil nutrient balance. quasi. It is forbidden to use chlorinated fertilizer on the avoidance of chlorine vegetables; no nitrate nitrogen fertilizer should be applied to leafy vegetables and root vegetables.
4, the principle of nutritional diagnosis and topdressing. According to the nutritional characteristics of vegetable growth and development, and the soil and plant nutrition diagnosis, the fertilizer is applied to meet the nutrient requirements of vegetables. For vegetables harvested at one time, especially leafy vegetables, nitrogen fertilizer should not be applied within 20 days before harvesting; for vegetables with continuous results, the number of top dressing should not exceed 4-5 times.
Second, pollution-free vegetable fertilization types In the production of pollution-free vegetables, the types and types of fertilizers allowed are:
1. High quality organic fertilizer. Such as compost, manure, biogas fertilizer, green manure, crop straw, mud fertilizer, cake fertilizer and so on. It should be fully decomposed before application.
2, biological fertilizer. These include humic acid fertilizers, rhizobial fertilizers, phosphorus bacterial fertilizers, and compound microbial fertilizers.
3. Inorganic fertilizers. Such as ammonium sulfate, urea, superphosphate, potassium sulfate and other NPK fertilizers that contain neither chlorine nor nitrate nitrogen, and vegetable fertilizers produced everywhere.
4. Trace element fertilizer. That is, copper, iron, boron, zinc, manganese, molybdenum and other trace elements and beneficial elements are mainly formulated fertilizers.
5. Other fertilizers. Such as bone meal, amino acid residue, livestock processing waste, sugar factory waste and so on.
Third, comprehensive implementation of soil testing formula balanced fertilization
In order to reduce pollution and give full play to fertilizer efficiency, balanced fertilization of soil testing formula should be implemented, that is, according to the nutritional and physiological characteristics of vegetables, the law of fertilizer absorption, soil fertility performance and fertilizer effect, the appropriateness of organic fertilizer, nitrogen, phosphorus, potassium and trace element fertilizers should be determined. The amount and proportion and the corresponding fertilization technology, to achieve symptomatic formula, symptomatic application. The specifics should include the variety and amount of fertilizer; the proportion of base fertilizer and top dressing; the number and period of top dressing; and the fertilization method used according to the characteristics of the fertilizer. Formulated fertilization is the basic fertilization technique for the production of pollution-free vegetables.
4. Precautions in fertilization of pollution-free vegetables
1. Organic fertilizers such as human excrement and manure should be fully fermented and decomposed, and rinsed with water after topdressing.
2, fertilizer, vegetable special fertilizer to deep application, early application, deep application can reduce nutrient volatilization, extend fertilizer time, improve fertilizer utilization. Early application is beneficial to early plant growth, prolonging fertilizer efficiency and reducing the accumulation of toxic substances such as nitrate. Generally, ammonium nitrogen is applied to the soil layer below 6 cm, urea is applied to the soil layer below 10 cm, phosphorus and potassium fertilizer is applied to the soil layer below 15 cm, and the special fertilizer for vegetables is applied to the soil layer below 15 cm.
3, according to the type of vegetables and cultivation conditions flexible fertilization, different types of vegetables, the accumulation of nitrates vary greatly, generally leafy vegetables are higher than melons, melons and vegetables are higher than fruit. In addition, the nitrate content of the same vegetable in different climatic conditions is also different, generally under high temperature and strong light, nitrate accumulation is less. Conversely, under low temperature and low light, nitrate is accumulated in large amounts. In the process of fertilization, the type of vegetables, cultivation season and climatic conditions should be considered, and the reasonable amount of chemical fertilizer should be mastered to ensure that the nitrate content is within the prescribed range of pollution-free vegetables.
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