How to reduce the nitrate content of vegetables

Nitrate has been shown to be reduced to nitrite by microbial action in and out of animals, which indirectly binds to secondary amines to form strong carcinogenic nitrosamines. Of the more than 120 nitrosamines currently found, 75% cause cancer in animals. 81.2% of the nitrates ingested by the human body come from vegetables. Therefore, researching and controlling the accumulation of nitrate in vegetables is of great significance for the protection of human health.

According to the agricultural biology classification of vegetables, the degree of accumulation of nitrate is as follows: root vegetables, yam, leafy vegetables, onion and garlic, beans, melons, solanaceous fruits, perennial vegetables, mushrooms . Fertilization techniques have the greatest impact on nitrate accumulation. Delayed harvesting reduces nitrate levels in vegetables. If nitrogen fertilizer is applied during the ripening period, it will increase the nitrate content in the vegetables. With the application of greenhouses, plastic greenhouses, plastic film and other equipment, if the fertilizer is not properly applied, it will increase the accumulation of nitrate in vegetables. Soil physical and chemical properties, vegetation cover conditions, etc., all affect the degree of nitrate pollution. The accumulation of clay loam is more, the accumulation of sandy loam soil is less; the soil temperature is reduced, the nitrification is inhibited, and the accumulation is increased; when the soil pH is high, the accumulation of nitrate is relatively small; for the soil with better vegetation, the nitrate content is relatively increased.

How can we control the pollution of nitrate to vegetables?

First, scientific fertilization. Green leafy vegetables should not be sprayed with nitrogen fertilizer such as urea or ammonium sulfate to avoid nitrate pollution. It is necessary to increase the application of farmyard manure or compound fertilizer, and pay attention to the supplement of potassium fertilizer and the utilization of micro-fertilizer, which can reduce the accumulation of nitrate.

Secondly, the vegetables produced in the protected area should increase the number and time of sheds, sheds and windows when they do not affect the temperature, so as to increase the light intensity, which is conducive to the assimilation of nitrates and the reduction of nitrate content.

Again, select vegetable varieties with high vitamin C content, such as tomatoes, peppers, and mushrooms. Because vitamin C can block or slow the formation of nitrate, inhibit the synthesis of nitrosamines.

Finally, vegetables should be avoided during harvesting and transportation, and should not be stacked for long periods of time at high temperatures. The rotted and degraded vegetables have an elevated content of nitrite and are not suitable for consumption.