SIBUR Modernized Glycol Production SIBUR Modernized Glycol Production
The SIBUR holding company completed a modernization of its production processes at its facilities in the Central region, reducing ethylene consumption in the...
Chemical Materials in Agriculture Chemical Materials in Agriculture:
Science does not stand still, and in agriculture new fertilizers are constantly being invented — formulations to improve the quality of grown produce,...
Overview Article: Ammonium Bifluoride We have prepared an overview article on the chemical properties of Ammonium bifluoride.
The article gives a general description of ammonium bifluoride from the standpoint of chemical reactivity. It...
How to Increase the Fire Resistance of Materials?
Flame retardants are used to improve the fire resistance of materials.
Flame retardants are substances added to materials of organic origin to increase their fire-resistant properties. They slow down the combustion and ignition of the material.
The action of flame retardants is based on:
1. melting...
Classification of dangerous goods by hazard level (ADR hazard class) in Russia is based on GOST 19433-88 "Dangerous goods. Classification and labeling," introduced in 1990.
Classes of Dangerous Goods:
Class
Subclass
Name
1
explosive materials
1.1
explosives with a mass explosion hazard
1.2
explosives with no mass explosion...
Mineral Fertilizers
Everyone knows that various fertilizers, both mineral and organic, are introduced into soil to increase its fertility.
Today the market offers a huge variety of products for mineral soil enrichment. Science continually studies and invents new and new combinations of mineral components, such as potassium, phosphorus, ammonia,...
Carbamide (Urea) is the most commonly used solid nitrogen fertilizer.
In nature, it occurs naturally in the urine of animals.
Urea is usually spread over the field, and plants break it down to absorb ammonia and ammonium.
This fertilizer moves fairly easily through the soil together with water. Leaching of the fertilizer depends largely on moisture levels until it breaks down into ammonia, ammonium (bicarbonate) and nitrate.
Urea in soil
As a rule, the breakdown of urea after application in the soil takes only a few days. Urea is capable of moving with water within a period of a few hours to two days after application, depending on the composition of the soil and the rate of breakdown.
Here are the main factors affecting the breakdown of urea:
The enzyme released by plants and/or microbes, urease, has its highest activity at the soil surface and decreases with depth. It should not be considered a significant factor when comparing different soils.
Soil temperature can affect the rate of breakdown — at 7 degrees Celsius, for example, the process proceeds much more slowly and can take up to a week, compared with 24 degrees. Studies give an approximate estimate that for every 10 degree increase in temperature, the reaction rate doubles.
Soil acidity — pH — the rate of breakdown increases as pH rises from 5 to 9. However, this is a conditional factor, since the onset of urea breakdown raises the soil pH to values above 9 — during breakdown to ammonium carbonate. However, nitrate is then formed, oxidation occurs, and the soil pH decreases back to its initial values. The overall effect of urea application on soil acidity is acidification. It is not recommended to apply urea to the surface without irrigation and/or place it next to seeds — this increases the rate of breakdown and results in loss of gaseous ammonia.
Moisture can strongly affect breakdown — for example, in very dry soil, breakdown stops. However, under normal agricultural conditions this is not a limiting factor. The higher the moisture level, the more active the breakdown reaction.
Foliar feeding with urea also gives good results — most of such feeding (up to 80%) is actively absorbed by the leaves. However, excessive application leads to necrosis or leaf burn.
When urea is applied, gaseous ammonia is released, which leads to its loss for uptake by plants. Studies have found that such losses can reach up to a quarter of the total volume of ammonia released. Therefore, all factors should be taken into account and urea should be applied to the soil correctly.
The plant enzyme urease accelerates the breakdown reaction the most — increasing the reaction rate by up to 800 times. Therefore, one direction for reducing ammonia losses is a urease inhibitor. Various additives are used for this.
One such additive, which is a natural material that does not pollute the soil or the plants themselves, is finely dispersed clay powder, for example Cambrian clay.
