Biuret缩二脲
Biuret is an impurity formed when two molecules of urea condense at elevated temperature during urea manufacture. At excessive concentrations it inhibits seed germination and seedling growth, making it a critical quality risk indicator for urea.
Key points
- Under GB/T 2440-2017, agricultural urea must contain no more than 0.9% biuret at premium grade and 1.5% at qualified grade; where prices are close, premium grade is the better choice.
- Risk is highest where urea is used as a starter fertilizer or placed in the seeding band — in those situations premium grade should be used, or a different nitrogen form substituted.
- Biuret also causes leaf scorch in foliar urea sprays, so a lower-biuret grade should be selected for that use.
- Under GB 38400-2019, the limits on toxic and harmful substances in fertilizers include biuret at no more than 1.5%.
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Category and source
- Category：Quality and labelling
- Definition basis：GB/T 2440-2017 Urea
Updated：Oct 16, 2026