Methods for fumigating soil include providing a fumigant including at least one volatile substance into or onto soil and applying over the soil a multilayer polymeric film to form a vapor barrier between the fumigant-treated soil and the atmosphere to at least partially contain the fumigant. The multilayer film includes at least one barrier layer comprising at least one vinylidene chloride polymer and protecting layers on each side of the barrier layer. The multilayer film preferably has at least one UV protecting layer and optionally at least one reflective layer.
