Deep placement of nitrogenous fertilizer (N) is an alternative for increasing the N use $ ciency of wetland rice besides minimizing the adverse e!ects of fertilizers on the environment. It has been found to limit the loss of N due to surface runo!, leaching, volatilization and denitri"cation that lead to reduction in applied N. Di!erent
machines as well as N materials (granular, urea supergranules or briquettes, liquid N) have been introduced for this method. Although deep placement of fertilizer increased N use e$ciency in rice-growing countries, the machines meant for this purpose have not been well accepted due to problems in performance consistency and commercial unavailability or extra cost of recommended materials. Despite these problems, however, several prototypes have shown potential but their acceptance maybe limited unless these promising mechanisms are adapted into a system that addresses the "eld and socio-economic conditions of Asian farmers. A fertilizer management system that combines machine deep placement, crop establishment and farmers' timing of application using the commercially available materials could enhance adoption of the technology. Further
re"nements of the promising devices as well as addressing farmers' constraints are, thus, recommended fora better acceptance of deep placement in the rice-growing countries of Asia