Accumulation of nitrates in plants
Nitrates are distributed unevenly in different plants, accumulating in certain zones. For example, cabbage accumulates nitrates in the stalk and upper leaves, cucumbers and squash in the peel, zucchini, beets, carrots in the lower part of the fruit, and potatoes in the middle. Experts recommend removing nitrate "zones", and pre-soak the potatoes.
To assess the suitability of vegetables for food, reference points were required. A large group of specialists created standards approved by the Ministry of Health. Here are these numbers: the permissible nitrate content (in mg per kg per nitration) in potatoes is 80, carrots - 300, cabbage - 300, onions - 60, tomatoes - 60. For early vegetables and grown in sheltered ground, these normative figures are doubled. But what if the permitted nitrate content in plants is significantly exceeded or there is a strong suspicion on this score? If the norm is exceeded to two times, vegetables are used in dispersal conditions, i.e., as part of dishes like salads. Or after boiling: up to 50% of the starting amount of nitrates or more is transferred to the broth, especially if the vegetables were chopped before cooking. Of course, the combination of these methods - dispersal and cooking - is quite acceptable and even useful, and not only in the catering, for which the recommendations are mainly designed, but also in home situations.
How to get rid of nitrates in products? Nitrates dissolve well. That is why vegetables should be boiled. The broth will leave most of the harmful compounds. When boiling potatoes and carrots in water it will be up to 60, for beets up to 40, and for cabbage up to 70% of nitrates contained in these products. In addition, it must be remembered that the roots and stems are more "rich" in nitrates, so it is better to cut them or cook longer than usual and also in large water.
© Rick Heath
There is another way to get rid of nitrates. When salting, pickling or pickling, their number is significantly reduced (up to 60% goes to brine). For example, sauerkraut contains much less nitrates than raw cabbage.
How does the nitrate content in vegetables change during storage? In the literature, the data are contradictory, but, in any case, a significant decrease in the level of nitrates can be expected only after a few months. And if so, then the time before harvesting becomes the main thing in nitrate control. According to the established procedure, a week and a half before harvesting in the fields and plantations, samples of vegetables are taken according to a certain scheme for research in specialized laboratories of regional and regional agricultural chemicalization stations.
An effective method of increasing the efficiency of agriculture and improving the use of fertilizers by plants is the use of irrigated and semi-cropped crops, which make good use of mobile residues of nitrate fertilizers.
Stable control of environmental pollution by chemicals used in agriculture has been established. Such control is entrusted to special agricultural departments existing in agrochemical laboratories and chemicalization stations.
Mineral fertilizers must not be completely excluded from agriculture completely and chemicalization in general cannot be. It is important to learn how to correctly use its achievements. If somewhere the negligent owner incorrectly disposed of the mineral fertilizers at his disposal, this should not mean that their use should be prohibited at all. This is the same as talking about the prohibition of the use of fire, as there are fires.
Many farms use biological methods to enrich the soil with nitrogen through perennial grasses. In a number of districts of Chuvashia, the crop structure has been changed: large areas are occupied by grasses. Changes have occurred in grass seed farms: the wedge of perennial grasses has been increased. This is the link that will stretch the whole chain: improve the structure, increase fertility, create the conditions for a complete transition to the production of biologically pure products. Many herbs well protect the soil from erosion, and at the same time improve it, enrich it with organic substances, especially clover, alfalfa, melilot. Clover on each hectare produces 150-200 kg of nitrogen, and taking into account the dry matter of root and crop residues, it replaces 30-40 tons of high-quality manure. This makes it possible to drastically reduce the application of nitrogen fertilizers.