Intercalation of magnesium–urea complex into swelling clay

Abstract N fertilization is considered as a main source of N 2 O and NO emission from agricultural soils. Especially, it is a great challenge to enhance urea efficiency without any deleterious effects on the environment because of massive application of urea. In this study, we attempted to stabilize urea in the interlayer space of montmorillonite (MMT) in order to reduce urea loss from soils. Urea was successfully intercalated in the form of urea–magnesium complexes. The stabilization of urea–magnesium complexes within the interlayer space was confirmed by a significant expansion of the interlayer space and the presence of urea–magnesium complexes. Urea degradation in soils was significantly delayed by application of the urea–magnesium complex intercalated into MMT. It is highly feasible that stabilization of urea within nanosized interlayer space would lead to considerable improvement of nitrogen efficiency in soils.