Ammonium nitrate is chosen as the main source of nitrogen for plants during the period of active growth by many gardeners and agronomists. This is due to its versatility: it can be used equally successfully for feeding almost all crops, and it is also suitable for most soil types.
A feature of the formula of ammonium nitrate is the presence of nitrogen in it in two forms - nitrate and amide - NH 4 NO 3 . Due to this, the period of assimilation of it from the soil by plants is somewhat extended. Nitrogen in the nitrate ion begins to be absorbed immediately after application under the root, but the amide is not earlier than a week after feeding.
Types of drugs
Usually this fertilizer is produced with the addition of various elements. This is due to the geographical extent of the use of ammonium nitrate, as well as the need to adapt to the needs of farmers in various climatic zones.
- Brand A. It is used in various industries. Must contain at least 98% ammonium nitrate and not more than 0.3% water. The content of conditioning (stabilizing) additives, which are usually used as magnesium and calcium nitrates, should be 0.2-0.5% for calcium oxide and 0.5-1.2% for P 2 O 5 .
- Brand B. Used exclusively for agricultural purposes. The nitrogen content in it should be at least 34%, and moisture, like brand A, should be no more than 0.3%. Ammonium nitrate of this particular brand is sold in garden shops and has a convenient packaging. It is divided into the highest, first and second grades, the main difference of which is the strength and size of the granules of the drug.
- Porous modified. This type of nitrate is used as raw material for the production of industrial explosives, which, in turn, are used in the mining, oil, gas, construction and other industries.
Ammonium nitrate production
The technological process of obtaining this fertilizer is quite complicated and includes several stages:
1. First get a solution of magnesium nitrate (magnesia supplement), which helps to improve the physico-chemical properties of nitrate:
Mg 2+ + 2HNO 3 → Mg (NO 3 ) 2 + H 2 O + Q.
This process takes 4 hours at a temperature of about 80 ° C and atmospheric pressure.
2. Nitric acid is neutralized with ammonia leading to the formation of ammonium nitrate in the form of a solution. This process is carried out at atmospheric pressure and a temperature of 148-165 ° C.
NH 3 + HNO 3 ↔ NH 4 NO 3 + Q.
3. A solution of ammonium nitrate enters the de-neutralizer, where the excess of nitric acid is neutralized by gaseous ammonia. To maintain an alkaline environment, a magnesia additive is introduced into the solution and sent to the stage of evaporation and granulation.
Storage and safety
Due to the fact that nitrogen, which is part of ammonium nitrate, has the ability to evaporate, the opened packaging with fertilizer must be used within a month. Nitrate sealed in a moisture-proof container is stored for no more than six months. At the same time, the room should be cool and there should be no direct sunlight.
This fertilizer is a fire and explosion hazard, its autoignition temperature is 350 ° C. But even at a temperature of 210 ° C it decomposes with the formation of nitrogen oxides and water vapor. And during the interaction of nitrogen oxides with nitrate, flammable oxygen and ammonia are released. When saltpeter is mixed with metal powders, sawdust or straw, sugar and some other organic substances, a large amount of heat is released, which can provoke the above process.
It is also recommended to protect the granules of the drug from mechanical influences, such as shock and friction, which can provoke an increase in their temperature.
Accumulation of nitrates in vegetables
Ammonium nitrate is a nitrate fertilizer. Thanks to the educational work of the media, many people have concluded for themselves that even a tiny amount of nitrates in products has a detrimental effect on the human body. And the reason for their accumulation in the fruits is exclusively mineral fertilizers, in particular, nitrate.
However, this view is erroneous. Firstly, nitrates not only come from food into living organisms, but also form in them during natural biochemical reactions. For comparison, the maximum allowable amount of nitrates that can be obtained with food without harm to health is 325 mg per day. And in the human body they form in the same day at least 100 mg.
Secondly, not nitrates themselves are harmful, but nitrites formed during their reduction. Symptoms of poisoning are nausea, weakness, diarrhea, shortness of breath. To alleviate the condition, it is necessary to rinse the stomach, take absorbents such as activated carbon, fresh air.
Thirdly, the accumulation of nitrates in fruits and vegetables can be triggered by shock doses of organic fertilizers, such as manure, bird droppings and even herbal infusions. It is important to feed the plants at certain periods of their growth and in the required quantities. As a rule, nitrogen fertilizers are stopped being applied 2-3 weeks before harvest.
It is also worth noting that not all plants with equal strength accumulate nitrates. Champions in their content are greens: dill, lettuce, parsley, as well as beets. But watermelons and melons with proper agricultural practices store nitrates even less than white cabbage.
Advantages
The popularity of using ammonium nitrate for fertilizing plants is due to a number of indisputable advantages:
- affordable cost of the drug;
- the possibility of using both in dry and in dissolved form;
- suitable for root and foliar top dressing;
- works well on cold soils in early spring;
- good diffusion ability.
The last property of ammonium nitrate allows the granules to dissolve perfectly in moist soil and penetrate into it quite deeply, providing nutrition to plants with a powerful root system. However, it is also included in the list of cons.
disadvantages
Due to the high solubility in too wet soils and in areas with a high level of groundwater, the application of this fertilizer is impractical, since it will immediately be washed out. Also, feeding performed before heavy rain will be ineffective.
Also, a significant disadvantage of the drug is its physiological acidity. Regular use on soils with a low base content (podzolic soils, subtropical red soils) provokes an increase in their acidity, and, consequently, a decrease in productivity. To neutralize this effect, it is recommended to add dolomite or lime to the soil.
Fertilizing Tomatoes
The introduction of ammonium nitrate during the cultivation of tomatoes can be done at the seedling stage. It promotes the growth of strong seedlings. Fertilizing tomato seedlings with nitrogen preparations is carried out three times:
- after picking: 10 g of ammonium nitrate is mixed with 10 g of potassium salt (KCl) and 40 g of superphosphate, and then the resulting mixture is dissolved in a bucket of water;
- 2 weeks after the first feeding: 15 g of saltpeter, 20 g of KCl and 70 g of superphosphate are dissolved in 10 liters of warm water;
- a week before disembarkation in the soil: 40 g of superphosphate and 60 g of potassium salt are taken per 10 g of ammonium nitrate, the mixture is dissolved in a bucket of water.
So that young plants do not receive chemical burns, it is important to pour them with plain water before dressing, and then with a solution of the drug. In this case, you must avoid getting it on the stems and leaves of seedlings. If drops of fertilizer have fallen on young herbs, then immediately rinse it with clean water.
The next top dressing is carried out already in the open ground and its duration depends on the quality of preparation of the planting holes. With proper agricultural technology, it is carried out after the seedlings adapt in a new place and its active growth begins. With the appearance of flowers and ovaries, fertilizing with ammonium nitrate should be stopped.
Feeding cucumbers
This culture is fed with ammonium nitrate as part of a mixture with other mineral fertilizers, providing potassium and phosphorus. Do this at least twice a season:
- After the appearance of two pairs of true leaves: 10 g of water should take 10 g of nitrate, KCl and superphosphate.
- At the beginning of flowering: 30 g of ammonium nitrate, 20 g of potassium salt and superphosphate in an amount of 40 g are dissolved in a bucket of water.
Since cucumbers develop quite quickly, this is enough to get a good harvest. Overfed with nitrogen, they will be reluctant to form ovaries, and this will affect the reduction in the number of fruits.
Potato dressing
A feature of this culture is underdeveloped roots and very large tubers, which accumulate various nutrients that enter and form in the plant. It is easy to imagine that when growing potatoes in the same place from year to year, the soil loses enormous amounts of trace elements. If you do not make their replenishment, then over time the tubers become smaller due to lack of nutrition.
When preparing a field for planting potatoes, it is necessary to disperse granules of ammonium nitrate at a rate of 30 g per 1 square meter immediately after snow melts. Dissolving in rainwater, it seeps to the desired depth, and subsequent harrowing of the site contributes to its uniform distribution. It is also recommended to combine nitrate with superphosphate, which is consumed in an amount of 15 g per 1 m 2 .
Root top dressing of potatoes with ammonium nitrate is carried out before hilling and after plentiful watering. A working solution is prepared at the rate of 20 g of nitrate and 40 g of superphosphate per 10 l of water.
The effect of the drug on the body
Ammonium nitrate can enter the body through the respiratory system, the gastrointestinal tract, getting on the skin and eyes. Nitrate dust when inhaled has an irritating effect on the upper respiratory tract, mucous membranes of the eye, skin (especially if there are cracks and wounds). Affected areas should be rinsed liberally with running water for 15 minutes. Rinse the nose and mouth thoroughly and provide the affected person with fresh air.
If nitrate enters the digestive tract, it causes dizziness, nausea and vomiting. As first aid, activated charcoal, a plentiful drink and saline laxative are used.