Discovered urea In 1773, the French chemist Hilaire Maren Rouel, isolating a certain compound from a liquid human vital product - urine. That is why the compound was called urea. In 1818, William Praout identified this substance, and in 1828 a German physician and chemist Weler obtained a substance similar to urea by evaporation of ammonium cyanate dissolved in water. The special significance of urea is that it is the first organic compound that was synthesized from inorganic, and from this event the history of organic chemistry begins.
What is urea (urea)?
Urea, or urea, is a chemical compound, carbonic acid diamide. It looks like odorless colorless crystals that dissolve in water, liquid ammonia, and ethanol. Technical urea is a white or yellow crystals. Pure urea contains more than 46% nitrogen.
Today, urea is used in a variety of industries. In the medical industry, it is the raw material for the manufacture of dehydration agents that remove water from the human body and are prescribed for cerebral edema. Urea is also used for the production of sleeping pills.
The use of urea as a food additive E927b enhances the taste and aroma of food. Most often it is added to bakery products, flour and used in the manufacture of chewing gum.
In the oil industry, urea is needed to remove paraffin substances from fuels and oils, as well as to clean smoke from nitrogen pipes of boiler houses, waste disposal plants and thermal power plants.
But the main part of the substance is used for agricultural needs: the urea fertilizer, made from urea, supplies nitrogen to the soil, which significantly increases its fertility and, consequently, contributes to an increase in crop yields. For example, feeding wheat with urea increases the protein content in it, as in other crops. Urea has a high activity and is quickly absorbed by plants. The use of urea is necessary first of all at the stage of pre-sowing tillage and during the period when the plants gain green mass, but urea top dressing during budding can subsequently negatively affect the amount of yield.
Urea solution preparation
How to dilute urea
The urea solution is used to feed almost all garden crops. Urea is produced in two forms:
- under the marking “A”, raw materials are sold for the production of feed additives for animals, as well as for the manufacture of glue and resin;
- urea is sold under the label “B” for use as a fertilizer.
However, despite the versatility and effectiveness of urea, which is used both as a main fertilizer and as a top dressing, it is very important to observe the correct proportions of urea for each plant when preparing the solution. For example, urea foliar dressing of ornamental trees and shrubs requires a solution of 18-32 g of urea in 10 l of water, and spring and summer leaf dressing of urea of vegetable crops is carried out with a solution of 51-62 g of fertilizer in 10 l of water at a flow rate of 3 l of solution per 100 m² of plantings .
The principle of preparing the solution is very simple: since urea dissolves well in water, pour the required amount of granules with 2 liters of water and stir until the carbamide is completely dissolved, then add water to the volume required by the instructions.
Urea plants are sprayed on the leaves to achieve maximum effect compared with the introduction of fertilizer granules into the soil, however, foliar treatment does not replace the root, just for each case you need to choose the most effective method.
Urea fertilizer - application in the garden
The introduction of urea into the soil is usually used when planting seedlings, although some gardeners prefer this method for further dressing, and plants treat only trace elements with leaves. Since urea, under the influence of soil bacteria, emits ammonium carbonate, which instantly decomposes in the open air, the surface application of urea granules is not effective. They need to be immediately planted into the soil to a depth of 7-8 cm. In autumn, under digging into the trunk circles of trees and bushes, 60% of the amount of granular urea necessary for plants in the season is added to the season. The remainder of the dose is closed in the spring. In order not to make a mistake in the dosage, you should know that 11 g of granulated urea will fit in one tablespoon, 14 g in a matchbox, and 131 g of urea in a two-gram glass. After applying dry fertilizer and incorporating it into the soil, plentiful watering is required. If you added compost or humus to the soil, then the dose of urea should be reduced by a third or half - it depends on the amount of organic matter added.
To fertilize the soil for vegetable crops, urea in dry form is introduced in the autumn for digging. Fertilizer consumption during the main application for tomato , garlic , potato , wild strawberry , flower plants and fruit crops, depending on the fertility of the soil, is from 130 to 200 g per m² of plot, but cucumbers and peas need only 5-8 g per unit area.
Processing the garden with urea in the form of a solution requires the observance of the correct dosage. To water the soil in the area where the roots of trees and bushes are located, you will need a concentrated solution. For example, for one adult apple tree , 200-250 g of urea must be dissolved in 10 liters of water, 120-130 g of urea per 10 liters of water will be enough for plums and cherries .
To water the soil under the currant bushes before sap flow, you need a solution of 20 g of urea in 10 liters of water, and urea treatment in the spring of gooseberries requires 10 liters of urea in the same 10 liters of water. During the growth of shoots of currants and gooseberries, the soil under the bushes is watered with a solution of 10 g of urea in 10 l of water.
Urea is very useful for tomatoes , cucumbers and cabbage , and the concentration of the nutrient solution should be the same as for trees, at a rate of 1 liter per plant. The prepared solution is poured in the required amount as close as possible to the root system.
However, keep in mind that urea acts acidifying on the soil, so acidic soils must be neutralized, that is, two weeks before or two weeks after feeding urea, chalk should be added to the soil at the rate of 400 g for every 500 g of urea. It is not possible to mix urea with chalk in the same way as with simple superphosphate, dolomite and lime.
Urea is sprayed early in the morning or after sunset, especially if the weather is hot. A urea solution for feeding plants on leaves during the spring-summer period is prepared at the rate of 30-40 g per 10 l of water. If you did not apply nitrogen fertilizers to the soil, then you can make the solution for spraying plants on leaves more saturated: the urea consumption in this case is about 100 g per 10 liters of water.
To spray vegetables, you need to dissolve 8-14 urea granules in 10 l of water. Feeding strawberries with urea requires a solution of 10 g of urea in 2 liters of water.
Urea for plants can serve not only as a nitrogen fertilizer, but also as an excellent means of combating some pests. Many gardeners prefer to use nitrogen in the plants as feeds and at the same time to kill insects spraying the urea of the garden in the spring, before the buds and trees begin to swell. For this, a seven percent urea solution is used. Spraying bushes and trees with a solution of urea is effective when the appearance of an apple beetle, aphid, weevil, and honeydew.
Urea also protects plants from pests: in autumn, it is recommended to treat scab apple and other fruit trees with a five percent urea solution: urea, penetrating the leaf tissue, deprives pathogens of the ability to form fruit bodies that cause primary infection of apple trees in spring. And from diseases such as monilial burn and purple spotting, urea with copper sulfate is effective: 700 g of urea and 50 g of copper sulfate are dissolved in 10 liters of water.
Keep in mind that if it rains after treating the plants with urea, you will have to spray again.
Urea for seedlings
Some vegetable crops are fed urea in the seedling period for an early harvest. After planting tomato seedlings in open ground or in a greenhouse, foliar feeding is carried out weekly, spraying the seedlings in turn with a solution of urea, potassium monophosphate and potassium nitrate. Three weeks after transplanting, urea is introduced under the root.
In total, during the season, plants can be fed with urea from 1 to 3 times under the root or 1-2 times on the leaves.