Urea 46% Nitrogen Fertilizer Bulk Granular Urea Urea fertilizer provides a rich source of nitrogen for crops. It is highly soluble and can be applied to the soil or used as a foliar spray for some plants (such as wheat and vegetables). It is important to incorporate urea fertilizer into soil rather than leaving it on top, especially when using it with high pH soils. Due to the chemical makeup of urea, nitrogen can be lost to the atmosphere in the form of ammonia gas if the fertilizer is not mixed in or irrigated heavily. Urea fertilizer can be mixed with calcium cyanamide, mono- or diammonium phosphate, or sulphate of potash. It is not recommended for mixing with superphosphate fertilizers.