It is not advisable to fertilize the vegetable land.

Vegetables are indispensable non-staple foods in people's daily life. However, when vegetables are grown, due to improper use of fertilizers, the quality is not good, and the quality and quality of vegetables are often poor. Chemical substances and toxic substances are seriously exceeded, which affects human health. After investigation, the author believes that to truly produce pollution-free vegetables, the use of fertilizers should be "five should not be".
It is not advisable to apply unfertilized raw manure. The so-called raw manure is a variety of organic fertilizers that have not been thoroughly decomposed, such as manure and human waste. These fertilizers are the bulk fertilizers in vegetable cultivation and the most common, most common and most easily accumulated fertilizer. If these fertilizers are not piled up, the eggs, germs and weed seeds in the fertilizer will not be killed by the high temperature. The eggs and germs will directly pollute the vegetables, affecting people's health, and the seeds of the weeds will grow at any time. Conquering water with vegetables will also affect the growth of vegetables.
It is not advisable to apply waste fertilizer. At present, garbage has become a major public hazard in the city. In some areas, it has become a reality to use garbage as a fertilizer to grow vegetables. Garbage can be divided into three categories, one is domestic garbage. Such as kitchen waste soup water, rotten melon vegetables, dead leaves and grass, these garbage can be used for composting, can increase the nutrient effect on vegetable growth; second, industrial waste. This kind of garbage contains bricks, sand, cement, plastic bags, glass shards, etc. Once turned into the soil, there is no effect of improving the soil, no nutrients for the supply of vegetables, and it is easy to cause the soil to deteriorate, and even cause the grass to grow. The situation; the third is hospital waste. Although it contains leftover soup, rotten rice, and fruit, it also contains wastes from various patients. Because the patients are mostly carriers, some germs are not easily killed after general treatment. If used as vegetable fertilizer, it will cause direct pollution to vegetables. This directly harms human health.
It is not suitable to apply nitrate nitrogen fertilizer. The fertilizer containing nitrate nitrogen in chemical fertilizer mainly includes ammonium nitrate and compound fertilizer containing nitrate nitrogen. These fertilizers will produce a large amount of nitrate ions when applied to vegetable fields, and vegetables need to absorb a large amount of nitrogen during growth. Fertilizer, nitrate ion is needed for vegetable growth, which increases the nitrate content of vegetables. This vegetable can be converted into nitrite into human gastrointestinal tract. Nitrite is a highly toxic substance. And carcinogens. Therefore, vegetable planting should be applied with ammonium nitrogen fertilizers such as: urea, ammonium sulfate, ammonium bicarbonate, etc., and should be re-applied to the base fertilizer, early application of top dressing, in addition, vegetables should not be applied to chemical fertilizers before harvest, to prevent vegetables Chemical substances exceeded the standard.
20 days before harvest, it is not suitable for foliar spray. There are quite a lot of vegetables for people to eat, such as cabbage, rape, cabbage, spinach, kale, leeks and sage. If the nitrogen fertilizer solution is applied to the foliage during its growth, the photosynthesis of the plant can make the leaves fresh and bright, and the color of the leaves will not increase due to the application of foliar fertilizer, but if Spraying the nitrogen fertilizer solution on the foliar surface within 20 days before harvesting will not only be beneficial to the growth of vegetables, but also increase the content of nitrate in the leaves, which will eventually cause the chemical substances in the vegetables to exceed the standard seriously. In addition, this "nitrogen vegetable" loses balance due to nitrogen and carbon, so that the water content of vegetables is increased, and the quality of the vegetables is deteriorated, which is not only resistant to storage, but also extremely perishable.
It is not appropriate to water the polluted water saying: water vegetables, water vegetables, no water, no vegetables, watering vegetables is a matter of course. Watering the vegetable fields requires pouring clean well water or unpolluted rivers and lakes and potholes. Some industrial wastewater, sewage from baths, sewage from hospitals or medical research institutions, some contain mercury, some contain cyanide, some contain a lot of lye, some contain infectious bacteria, if you use these waste water to water vegetables, In addition to directly causing pollution of vegetables, it can also destroy the structure of the soil, making the fertile soil worse and losing the value of planting.

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