Fertilizer and the problem of nitrates in fruits and berries
With the use of fertilizers, especially minerals, has recently attributed the emergence of environmental and toxicological and hygienic problems.Particularly acute problem has acquired accumulation of nitrates in crop production.
Nitrates are one of the main sources of nitrogen nutrition of plants.By doing it, they go through a series of complex transformations, including in the composition of proteins, nucleic acids and other compounds.Thus, the nitrate nitrogen is an essential component of natural and plant organism.Excessive accumulation of nitrate same indicates that the plant does not have time to use them for the biosynthesis of organic compounds.In this case the plants do not suffer from this, and can store a large number of them.
However, for a person consuming food such plants or products from them, it is by no means indifferent.Nitrates, getting into the human body with plant food, is reduced to nitrite, which lead to the formation of methemoglobin and disturbance of the transport function of
Therefore, the problem is not how to eliminate all flow of nitrates in the plant, and to their number in the product does not exceed the maximum allowable amount - an indicator of the MPC.It was found that the maximum allowed daily dose of nitrates to humans an average of 300 mg.Approximately 80% of the nitrate comes from vegetables, the rest - with drinking water, meat, bread and other products.
Receipt nitrate with fruits and berries is very small, becauseThese plants are not capable of their accumulation (PDK- 50-60mg / kg).
This is due to the biological characteristics of fruit and berry plants are not able to accumulate a lot of nitrates.Processing them nitrates occurs primarily in the roots and thus a significant accumulation in their bodies and the aboveground, primarily in fruit and berries should not take place.If this happens, then we can talk about violation of protective functions of the root systems and nitrogen metabolism in all plant organs.
excess nitrates in plants and products occurs when the soil is absorbed by them more than is required for the synthesis of protein compounds.This happens most often when applying excessive doses of nitrogen fertilizer, as well as due to the imbalance between the content of nitrogen, phosphorus and potassium.Greater nitrate accumulation contributes to the cultivation of plants in shaded conditions and cloudy weather, when the attenuated process of photosynthesis.
And no way to agree with the fact that mineral fertilizers can not be used in plant breeding.
Here are two examples.
1. With natural grass meadows took samples and analyzed it on the nitrate content.It turned out that in their samples is more than the maximum allowable amount.The question is: where are the fertilizer?- They had not been brought.However, the power plant has appeared unbalanced, and this has led to an excess of nitrates.
2. In the experiment with black currant studied different doses of mineral fertilizers - by the lack (so-called "zero control") to very high in various ratios.Where are nitrates above the allowable amounts were found?In the control variant - without fertilizer.And on plots with high doses of fertilizers, but in the right proportions, received the biggest crop of berries without nitrates.
To reduce the risk of accumulation of nitrates in fruits and berries must be observed fertilizer application technology and to create conditions conducive to the processing of nitrates in plants.
Factors that reduce the accumulation of nitrate in the production:
1. Exclusion of a unilateral and excessive (more than 20 gd.v. / m2), nitrogen fertilizer.Balancing supply by making phosphate, potash and other fertilizers in the recommended doses.
2. Exclusion of nitrogen fertilizing during ripening.
3. The combined use of mineral and organic fertilizers, improving conditions for the development of soil microflora, absorbing the excess of nitrogen in soil.
4. Maintaining optimal soil moisture.
5. Good lighting plants.
6. Using stored and processed products.
Years of experience shows that a balanced diet of garden plants with a rational use of organic and mineral fertilizers not only increases their productivity and resistance to adverse environmental factors, but also provides an environmentally safe products.