1. What are the ammonium nitrogen fertilizers
There are many kinds of ammonium nitrogen fertilizers, mainly ammonium sulfate, ammonia, ammonium bicarbonate, liquid ammonia, ammonium chloride and so on. They have many things in common. For example, they are easily adsorbed by soil colloids, and will become nitrates after oxidation.
This kind of fertilizer is particularly easy to volatilize in an alkaline environment. When used, if the plant or crop absorbs too much, it will have an inhibitory effect, and if the concentration is too high, it will cause toxicity.
Ammonium nitrogen fertilizers are generally water-soluble fertilizers. The ammonia molecules or ammonium ions in them are easily oxidized to nitrate nitrogen under good aeration conditions, and they are easily leached out by water after oxidation. If you want to weaken nitrification, you can use it with a nitrification inhibitor.
Second, why should ammonium nitrogen fertilizer be deep-covered?
1. Ammonium nitrogen fertilizer is easier to decompose ammonia under alkaline conditions and cause volatilization, so it is generally necessary to apply deep cover soil when applying it on calcareous soil or alkaline soil.
In acidic conditions, ammonium nitrogen fertilizer will exist in the form of ammonium ions (nh4+). At this time, it will not volatilize, but if it is applied shallowly on dry land, it is prone to nitrification and further denitrification, which will cause nitrogen loss. . Therefore, when applying on acid soil, cover soil must be applied deeply.
2. Ammonia nitrogen fertilizer will easily cause ammonia volatilization after being applied to the soil. If it is used in an alkaline environment, the volatilization loss will be more serious.
The fertilizer will be converted into nitrate nitrogen after nitrification by nitrifying bacteria in the soil, which will produce biological acidity, leading to the loss of soil base ions, and long-term large-scale application is easy to acidify the soil.
3. Ammonium nitrogen fertilizers are relatively soluble in water, and can produce ammonium ions and corresponding anions, so that they can be directly absorbed and utilized by crops.
The ammonium ions in the ammonium nitrogen fertilizer can be exchanged with the cations on the soil colloidal particles, and then they can be adsorbed on the soil colloidal particles to form exchangeable nutrients.
After ammonium ions are adsorbed, the mobility will be relatively small and not easy to lose. It can be gradually absorbed and utilized by crops, so it has a longer fertilizer effect than nitrate nitrogen fertilizer.
3. Precautions for the use of ammonium nitrogen fertilizer
1. Ammonia molecules or ammonium ions in ammonium nitrogen fertilizers are easily oxidized to nitrate nitrogen under good aeration conditions, and are easily leached out by water after oxidation. In order to weaken the nitrification effect, it can be used in conjunction with a nitrification inhibitor.
2. The ammonium ions in ammonium nitrogen fertilizer can be adsorbed by soil colloid, and the fertilizer effect is stable after adsorption.
3. Ammonium nitrogen fertilizer is volatile in alkaline environment, so it should be avoided as much as possible to mix with alkaline fertilizer.
