Correct understanding of green vegetables and fertilizer application

Green vegetables in fertilization technology requirements: based on organic fertilizer to improve soil fertility level; insert legume crops to increase soil nitrogen content, reduce the amount of chemical nitrogen fertilizer; strictly control the nitrogen fertilizer top dressing time, control the nitrate content of the vegetable body. In the process of producing vegetables that meet the green food standards, there should be a correct understanding of the application of chemical fertilizers.

　　 1. Green food and fertilizer application are not contradictory. Do not oppose green foods with chemical fertilizers. Chemical nitrogen fertilizers are inorganic nitrogen sources that can be directly absorbed by vegetables. Organic fertilizers are decomposed by microorganisms to convert organic nitrogen into inorganic nitrogen. Finally, inorganic nitrogen is used for vegetables. Absorbed. Therefore, it is considered that "the vegetables using chemical fertilizers are not vegetables of green food standards", and the view that "the vegetables using organic fertilizers are the vegetables of green food standards" is incorrect. In fact, some vegetables that use organic fertilizers in large quantities have a lot of nitrate in the body.

　　 2. Properly control the amount of nitrogen fertilizer. In order to ensure that the green food standard vegetables have good yield and economic benefits, on the basis of the application of organic fertilizers, the necessary application of nitrogen fertilizer is necessary, but the dosage must be controlled. In the current situation where green food and vegetables are not based on quality, it is difficult to solve the contradiction between quality and yield, yield and benefit without applying chemical nitrogen fertilizer. Vegetable farmers are also unacceptable.

　　 3. Strictly master the time of topdressing of nitrogen fertilizer. The nitrate content of vegetable crops is constantly changing. Because the nitrogen that enters the vegetable body is further converted into amino acids and synthesized in the metabolic process. According to the research, with the passage of nitrogen fertilizer, the nitrate content in vegetables has gradually decreased. It has now been applied per acre organic fertilizer 5000 kg and 25 kg of ammonium sulfate fertilizer as an example oilseed rape, canola nitrate content from 3 days dressing 5372 mg / kg, 14 days down to 877.4 mg / kg, and 18 days 653.8 The mg / kg has been in line with the green food recommendation. Therefore, from the safety point of view, the topdressing time of green food vegetables should be 15-20 days before harvesting . In addition, nitrogen fertilizer combined with potassium fertilizer can promote protein synthesis and reduce nitrate content in the body.

In short, in order to obtain high-quality, non-polluting vegetables and develop green food production, there are many problems that should be paid attention to in fertilization. The key to this is to raise the awareness of the farmers on the above issues. (Ma Jing)

Source: Xingtang County Agriculture, Forestry and Animal Husbandry Bureau