All forms are subject to leaching after they are converted into nitrate.
One reason nitrates leach or escape into the air is their electrical charge. Nitrate molecules have a negative charge that is similar to that of the soil particles. Therefore they are not held tightly by the soil. Molecules of ammonium-based fertilizers are held more tightly by most soils. Therefore, the loss of nitrate can be greatly reduced by use of ammonium-based fertilizers such as anhydrous ammonia, says Bauder.