What is the function of nitrogen fertilizer? How to choose?

Nitrogen fertilizer refers to nitrogen (N) as the main component, with N marked amount, applied to the soil can provide plant nitrogen nutrition unit fertilizer. In the agricultural production process, plant growth cannot be separated from nitrogen fertilizer. What is the role of nitrogen fertilizer? How to choose?

What is the role of nitrogen fertilizer?

The effect of nitrogen on plant growth and development is very obvious. When nitrogen is sufficient, plants can synthesize more protein, promote cell division and growth, so plant leaf area increases, and more leaf area can be used for photosynthesis.

In addition, the abundance or deficiency of nitrogen was closely related to the chlorophyll content in leaves. The supply of nitrogen can be judged from the size of leaf area and leaf color. In the seedling stage, nitrogen deficiency in general plants is often manifested as slow growth, short plants, thin and small leaves, and green and yellow leaves. Gramineous crops showed less segregation. When nitrogen deficiency was serious in late growth stage, panicle was short and grain was not full. After increasing nitrogen fertilizer, it has obvious effect on promoting plant growth and health. Often after application, leaf color quickly turned green, growth increased.

How to choose nitrogen fertilizer?

There are many varieties of nitrogen fertilizer, which can be divided into ammonium nitrogen fertilizer, nitrate nitrogen fertilizer and amide nitrogen fertilizer according to the form of compounds. Ammonium nitrogen fertilizer includes ammonium bicarbonate, ammonium sulfate, ammonium chloride, ammonia, liquid ammonia, etc.; nitrate nitrogen fertilizer includes ammonium nitrate, sodium nitrate, calcium nitrate, etc.; amide nitrogen fertilizer includes urea, calcium cyanamide (lime nitrogen), etc. In order to improve the effect of nitrogen fertilizer application, scientific selection of nitrogen fertilizer varieties is very important.

Generally speaking, crops with high carbohydrate content such as potatoes are suitable for ammonium nitrogen application. Ammonium nitrogen and nitrate nitrogen were equally effective in wheat and maize, but ammonium nitrogen was still recommended in rainy areas to prevent nitrogen leaching.

Urea and ammonium chloride are better than ammonium sulfate and nitrate nitrogen fertilizer in paddy field. Because sulfate is easy to reduce to hydrogen sulfide in paddy field, it makes rice root black or even rotten, nitrate is easy to leach with water in paddy field and denitrification causes nitrogen loss.

Hemp crops should choose ammonium chloride, because chloride ions can increase fiber toughness and tensile force. Nitrate nitrogen could improve the combustibility of tobacco, while ammonium nitrogen could promote the formation of aromatic volatile oil in tobacco leaves and increase the flavor of tobacco. Therefore, the combination of two forms of nitrogen fertilizer could improve the quality of tobacco.

Ammonium sulfate applied to sulfur-deficient soils helps to improve sulfur nutrition of crops. Ammonium chloride should not be applied to tobacco, grape, potato, sweet potato, beet, citrus, tea, sugarcane, watermelon, melon and other chlorine-sensitive crops, otherwise it will obviously affect their yield and quality.