Availability of NH4+ N in the surface soil (0-15 cm) was initially lower from deep-placed USG compared with prilled urea split and neem-coated urea, but increased up to 45 d after transplanting (Patel et al 1989).
Prilled is a term used in mining and manufacturing to refer to product that has been pelletized. The pellets are a neater, simpler form for handling, with reduced dust. Certain agrochemicals such as urea are often supplied in prilled form