Physical Description:
All Urea contains biuret, a phytotoxic impurity in urea that can cause agronomic problems. Ravensdown's Low Biuret Urea contains less than 0.4% biuret, therefore removing the potential harm that can be caused by this compound.
Uses:
Low Biuret Urea is mainly used as a foliar spray on high value tree crops such as avocados and citrus as a source of nitrogen and also to help reduce the risk of frost damage.
Benefits:
All Urea contains biuret, an impurity in urea that can cause agronomic problems. This is usually not a problem, as most crops grown in New Zealand have a biuret tolerance of 4-5%. However, some crops are sensitive to biuret, where high levels can cause leaf burn. To reduce this risk low-biuret urea is recommended for foliar applications on high value horticultural crops. Ravensdown's specification for low biuret urea is that the urea contains less than 0.4% biuret, with actual levels typically in the range of 0.2-0.3%. Standard urea has a biuret concentration of approximately 0.8%.
Application:
The rate of foliar applications will vary from crop to crop: for most tree crops (e.g. avocados, kiwifruit) the concentration of low biuret urea dissolved in water is 0.5-1.0%. If unsure, consult a field officer dealing with tree crops for guidance.
Storage & Handling:
As with most solid fertilisers, Low Biuret Urea can be stored over a season as long as it is kept in a cool, dry, well ventilated area.