At present, the types of urea in the fertilizer market are also diverse, including large particle urea, small particle urea, polypeptide urea, slow release urea, coated urea, urea formaldehyde urea and the like. I will introduce them separately today.
1. Ordinary urea
The nitrogen content in urea is higher, and the nitrogen content of qualified products is 46.0%. The first-class product requirements are 46.2%, and the superior products are 46.4%, which can be used as base fertilizer and top dressing. It can also be sprayed on the foliar surface after dissolution, but the concentration must be paid attention to when spraying. Field crops are sprayed at concentrations ranging from 1% to 2%. The spraying concentration of vegetables such as open vegetables, melons and fruits is 0.5%-1%. The concentration of greenhouse vegetables sprayed is 0.2%-0.4%. Urea is also divided into large granular urea and small granular urea. Large particle urea generally has a particle size of 2-4 mm. Small particle urea has a particle size of 1-2 mm. Because of the large size of the particles, the large-particle urea dissolves slowly in the soil, and is generally used as a raw material for the fertilizer and the fertilizer plant. Small granular urea is generally used as a top dressing. Urea is an organic nitrogen that cannot be directly absorbed by crops and needs to be converted to ammonium bicarbonate by urease before it can be absorbed by crops. The activity of urease is related to soil temperature, humidity, pH, and microbial activity. When the temperature is 10 ° C, urea needs 7-10 days of conversion. When the temperature is 20 degrees, it takes 4-5 days. When the temperature is 30 degrees, it takes 2 days. When selecting urea, it is also necessary to pay attention to the content of biuret. Biuret is a crop growth disorder agent. When the biuret content exceeds 2%, seed germination is inhibited. Poisoning can occur after the crop is absorbed.
2. Polypeptide urea
The nitrogen content of the peptide urea is still 46-46.4% as the normal urea content. However, the fertilizer is longer than ordinary urea and can be used as a base fertilizer, top dressing and production of slow release fertilizer. However, when it is used as a top dressing, it is better to mention the date than the normal topdressing. In terms of production process, the polypeptide urea refers to the addition of metalloproteinase or polyaspartic acid to the urea production process. As a plant nutrient absorption enhancer in agriculture, polyaspartic acid can effectively promote the absorption of trace elements such as iron, zinc and manganese by crops. Metalloproteinases can stimulate the synthesis of sugar and vitamins in plant cells, and also promote the development and enhance the resistance of crops. Therefore, the addition of these two substances to the polypeptide urea has the effect of promoting early maturity, root development, and improving the stress resistance of the crop. Indirectly, it also increases the utilization rate of fertilizer and prolongs the fertilizer efficiency.
3. Slow release urea
Slow release urea is a certain proportion of urease inhibitor added in the ordinary urea production process. It can reduce the loss of nitrogen, thereby improving fertilizer efficiency and prolonging fertilizer efficiency. The amount of inhibitor added in slow release urea is small, and has little effect on the physical and chemical properties of urea. Therefore, the nitrogen content is the same as the ordinary urea content, but the fertilizer effect is longer, generally 80-120 days. Slow-release urea is mainly used to produce slow-release nitrogen in slow-release fertilizers.
4. Coated (controlled release) urea
The coated urea is coated with a semi-permeable or impervious material on the surface of the urea, so that themicropores and gaps through which the nutrients pass are slowly released. Thereby, the controlled release of nitrogen nutrients is slowly released, and the fertilizer utilization rate is improved. The coated urea mainly has sulfur-coated urea and resin coated urea. Sulfur-coated urea generally has a nitrogen content of 36-37%. The urea nitrogen content of the resin coating is 38-42%, and the fertilizer efficiency is generally 80-120 days. The two ureas are mainly used to produce controlled release nitrogen in controlled release blended fertilizers. Although resin urea has long-term fertilizer efficiency, it also has some problems in fertilizer production. 1. Some coated urea coatings are very brittle and tend to fall off during transportation. 2, some coatings are not thick and uneven, the rate of release of fertilizer effect is not the same. 3. Some resin materials are not easy to degrade and easily pollute the environment.
5. Urea formaldehyde urea
Urea formaldehyde urea is a product of the reaction of urea with formaldehyde at high temperatures. However, this product is not a single substance, and mainly consists of two colloids of 1 methylene 2 urea and 2 methylene 3 urea. The effect of 1 methylene 2 urea is 40 to 80 days, and the effect of 2 methylene 3 urea is 80 to 120 days. The length of urea formaldehyde fertilizer is mainly achieved by controlling the temperature at which the reaction takes place and the amount of urea. Urea formaldehyde urea has a long-lasting effect and is generally used as a raw material for producing urea-formaldehyde fertilizer nitrogen fertilizer.
Lianyungang JM Bioscience NBPT Manufacturer supplies a variety of urea fertilizer. If you need, please contact us.