Urea is a white crystal, which is stable at room temperature. When heated to more than 50 degrees, urea will decompose, resulting in the loss of its original effect. High temperature will trigger the chemical reaction inside urea molecules and destroy the structure and properties. Urea is one of the main components of agricultural chemical fertilizer, and the effective component is nitrogen-containing compound. Heating to high temperature will decompose urea, resulting in ineffective release of nitrogen and affecting its effect as fertilizer.